JP2010079270A - Method of forming pattern, and photosensitive composition to be used therefor - Google Patents

Abstract

Kind Code: A1 A pattern forming method and a photosensitive composition used therefor, which are used for forming a fine pattern in semiconductor manufacturing, can form a pattern with reduced line width roughness (LWR), and enable a wide exposure latitude. To do.
A process of forming a photosensitive film from a photosensitive composition, a process of irradiating the photosensitive film with actinic rays or radiation, a heating process (PEB process), a developing process, a rinsing process, and a post-baking process. A pattern forming method comprising: at least one resin contained in the photosensitive composition, wherein the glass transition temperature is within the range of the formula (1), and the photosensitive composition used therefor.
Formula (1): Heating temperature in post-baking process + 20 ° C ≧ Glass transition temperature of resin> Heating temperature in PEB process [selection figure] None

Description

  The present invention relates to a pattern forming method using a photosensitive composition used in a semiconductor manufacturing process such as an IC, a manufacturing process of a circuit board such as a liquid crystal and a thermal head, and other photofabrication processes. More specifically, the present invention relates to a pattern forming method using a photosensitive composition suitable for the case where far ultraviolet rays or electron beams of 250 nm or less, preferably 220 nm or less are used as an exposure light source.

The chemically amplified photosensitive composition generates an acid in the exposed area by irradiation with radiation such as far ultraviolet light, and the acid-catalyzed reaction causes the solubility of the active radiation irradiated area and non-irradiated area in the developer. This is a pattern forming material for changing the pattern to form a pattern on the substrate.
When a KrF excimer laser is used as an exposure light source, a resin having a basic skeleton of poly (hydroxystyrene) having a small absorption mainly in the 248 nm region is used as a main component, so that high sensitivity, high resolution, and good A pattern is formed, which is a better system than the conventional naphthoquinone diazide / novolak resin system.

On the other hand, when a further short wavelength light source, for example, an ArF excimer laser (193 nm) is used as an exposure light source, the compound having an aromatic group exhibits a large absorption in the 193 nm region. It wasn't.
For this reason, an ArF excimer laser resist containing a resin having an alicyclic hydrocarbon structure has been developed. For example, Patent Documents 1 and 2 describe a composition containing a resin having a repeating unit having an acid-decomposable group having a polycyclic structure and a non-acid-decomposable repeating unit. Patent Document 3 discloses a resist composition containing a specific sulfonic acid generator.
The resists described in these publications are chemically amplified resists containing a resin having a protecting group unstable to an acid, which is dissociated by an acid. However, further miniaturization of the resist pattern is required. Improving line edge roughness has become an urgent issue. For example, in a line and space pattern with a pitch of 100 nm, when the line pattern is 50 nm, the line width roughness (LWR) is required to be 5 nm or less. That is, as the miniaturization progresses, it is necessary to control the LWR to 10% or less with respect to the line width.

Further, when LWR is suppressed, there is a tendency that the pattern size tends to fluctuate due to the fluctuation of the exposure amount, that is, the exposure latitude tends to narrow.
A conventional pattern formation method using a resist composition is not yet sufficient, and it has been desired to achieve both LWR and exposure latitude in a trade-off relationship.

JP 2003-167347 A Japanese Patent Laid-Open No. 2003-223001 JP 2005-173549 A

  The present invention has been made in view of the above-described background, and its purpose is to form a pattern with reduced line width roughness (LWR), which is used for fine pattern formation in semiconductor manufacturing, and has a wide exposure latitude. An object of the present invention is to provide a pattern forming method that can be performed and a photosensitive composition suitable for the method.

As a result of intensive studies to solve the above problems, the present inventors combined a photosensitive composition containing a resin having a specific glass transition temperature range and a process focusing on the temperature of the PEB process and the post-bake process. Thus, it was found that a pattern excellent in LWR and exposure latitude was obtained.
The present invention has been developed in view of the above findings, and the object of the present invention has been achieved by the present invention shown below.

(1) including a step of forming a photosensitive film from the photosensitive composition, a step of irradiating the photosensitive film with actinic rays or radiation, a heating step (PEB step), a developing step, a rinsing step, and a post-baking step. It is a pattern formation method, Comprising: The glass transition temperature of at least 1 resin contained in this photosensitive composition exists in the range of Formula (1), The pattern formation method characterized by the above-mentioned.
Formula (1): Heating temperature in the post-baking process + 20 ° C. ≧ glass transition temperature of the resin> heating temperature in the PEB process

(2) The pattern forming method as described in (1) above, wherein the heating temperature in the PEB step is 115 ° C. or lower and the heating temperature in the post-baking step is 115 ° C. or higher.

(3) The pattern forming method as described in (1) or (2) above, wherein the film thickness of the photosensitive film is in the range of 5 nm to 300 nm.
(4) Any of the above (1) to (3), characterized by containing a resin that satisfies the following condition: heating temperature in post-baking process + 20 ° C. ≧ glass transition temperature of resin> heating temperature in PEB process The photosensitive composition used in the pattern formation method of description.

  According to the present invention, LWR and exposure latitude performance are improved, and it is possible to provide a method for forming a fine pattern in semiconductor manufacturing and a photosensitive composition that can be suitably used for pattern formation.

  Hereinafter, the present invention will be described in detail.

The pattern forming method of the present invention includes a step of forming a photosensitive film with a photosensitive composition, a step of irradiating the photosensitive film with actinic rays or radiation, and a subsequent heating step (Post Exposure Bake: hereinafter referred to as PEB step). , Development step, rinsing step, and heating step (Post Bake: hereinafter referred to as a post-bake step), wherein the glass transition temperature of at least one resin contained in the photosensitive composition is a formula It is characterized by being in the range of (1).
Formula (1): heating temperature in post-baking process + 20 ° C. ≧ glass transition temperature of resin> heating temperature in PEB process Resin having a predetermined glass transition temperature satisfying formula (1) is a resin contained in the photosensitive composition The total content is preferably 20% by mass or more, more preferably 30 to 100% by mass, and most preferably 40 to 100% by mass. It is considered that the predetermined resin is preferably present in the vicinity of the pattern surface in order to reduce LWR.

The resin having a predetermined glass transition temperature satisfying the formula (1) may be any resin contained in the photosensitive composition such as resins (A), (D), and (HR) described later.
The glass transition temperature of the resin can be measured, for example, by the following method.
When a polymer substance is heated, a phenomenon that changes from a glassy hard state to a rubbery state is called a glass transition, and a temperature at which the glass transition occurs is defined as a glass transition point (Tg). As a method for measuring Tg, a method based on differential scanning calorimetry (DSC method) can be used. In DSC method, the test piece is heated from room temperature at a rate of 20 ° C / min, the calorific value is measured with a differential scanning calorimeter, and two extension lines are added to the created endothermic curve (two-stage exothermic curve). Tg can be obtained from the intersection of the ½ straight line between the extension lines and the endothermic curve.

In the pattern forming method of the present invention, the heating temperature in the PEB process is preferably 115 ° C. or lower, and the heating temperature in the post-baking process is preferably 115 ° C. or higher.
Moreover, it is preferable that the film thickness of this photosensitive film exists in the range of 5 nm-300 nm.
Moreover, Tg of resin is 135 degreeC-220 degreeC, the heating temperature of PEB process is 60 degreeC-180 degreeC, the heating temperature of a post-baking process is 115 degreeC-200 degreeC, and each temperature which satisfies general formula (I) Preferably there is.

[Pattern formation method]
Hereinafter, in the pattern forming method of the present invention, a step of forming a photosensitive film with a photosensitive composition, a step of irradiating the photosensitive film with actinic rays or radiation, a PEB step, a developing step, a rinsing step, and post-baking The process will be described in detail.
In the step of forming a photosensitive film with the photosensitive composition, the photosensitive composition is applied to a spinner, coater, etc. on a substrate (eg, silicon / silicon dioxide coating) used for manufacturing a precision integrated circuit device. The photosensitive film is formed by coating and drying by an appropriate coating method.
The drying temperature is preferably 60 ° C to 180 ° C, more preferably 65 ° C to 150 ° C, and most preferably 70 ° C to 140 ° C. The drying time is preferably 30 seconds to 120 seconds, more preferably 40 seconds to 110 seconds, and most preferably 50 seconds to 100 seconds.

Before forming the photosensitive film, an antireflection film may be coated on the substrate in advance.
As the antireflection film, any of an inorganic film type such as titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, and amorphous silicon, and an organic film type made of a light absorber and a polymer material can be used. In addition, as the organic antireflection film, commercially available organic antireflection films such as DUV30 series, DUV-40 series manufactured by Brewer Science, AR-2, AR-3, AR-5 manufactured by Shipley, etc. may be used. it can.

In order to form a pattern, the photosensitive film is usually irradiated with actinic rays or radiation through a predetermined mask.
Examples of the actinic ray or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, X-rays, and electron beams. The photosensitive composition of the present invention does not depend on the light source, and LWR and exposure. A pattern with improved latitude is obtained. The actinic ray or radiation is preferably 250 nm or less, more preferably 220 nm or less, particularly preferably far ultraviolet light having a wavelength of 1 to 200 nm, specifically KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ₂ excimer laser (157 nm), X-ray, electron beam, etc. ArF excimer laser, F ₂ excimer laser, EUV (13 nm), and electron beam are preferable.
It has a heating process (PEB process) after the process of irradiating actinic rays or radiation.
The temperature in the PEB process is preferably 60 ° C to 180 ° C, more preferably 65 ° C to 150 ° C, and most preferably 70 ° C to 115 ° C. The PEB time is preferably 30 seconds to 120 seconds, more preferably 40 seconds to 110 seconds, and most preferably 50 seconds to 100 seconds.

Examples of the developer used in the development process include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, and primary amines such as ethylamine and n-propylamine. Secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, etc. Alkaline aqueous solutions of quaternary ammonium salts, cyclic amines such as pyrrole and pihelidine can be used.
Furthermore, an appropriate amount of alcohol or surfactant can be added to the developer.
The alkali concentration of the developer is usually from 0.1 to 20% by mass.
The pH of the developer is usually from 10.0 to 15.0.
Furthermore, an appropriate amount of alcohol or surfactant may be added to the alkaline aqueous solution.
The development time is preferably 5 seconds to 200 seconds, more preferably 6 seconds to 150 seconds, and most preferably 10 seconds to 130 seconds.

The rinsing liquid used in the rinsing step contains water as a main component, usually pure water, and an appropriate amount of a surfactant can be added.
Further, after the development step or the rinsing step, a process of removing the developer or the rinsing solution adhering to the pattern with a supercritical fluid can be performed.
The rinsing time is preferably 5 seconds to 500 seconds, more preferably 10 seconds to 300 seconds, and most preferably 10 seconds to 150 seconds.
And in a post-baking process, in order to remove the water | moisture adhering after the rinse process, it heats.
The temperature in the post-baking step is preferably 80 ° C to 200 ° C, more preferably 90 ° C to 180 ° C, and most preferably 115 ° C to 160 ° C. The post-bake time is preferably 30 seconds to 120 seconds, more preferably 40 seconds to 110 seconds, and most preferably 50 seconds to 100 seconds.

In the above-described processes requiring heating, means that can be normally used for patterning, such as a hot plate, can be used.
Note that exposure (immersion exposure) may be performed by filling a liquid (an immersion medium) having a higher refractive index than air between the photosensitive film and the lens during irradiation with actinic rays or radiation. Thereby, resolution can be improved. As the immersion medium to be used, any liquid can be used as long as it has a higher refractive index than air, but pure water is preferred.

The immersion liquid used for the immersion exposure will be described below.
The immersion liquid is preferably a liquid that is transparent to the exposure wavelength and has the smallest possible temperature coefficient of refractive index so as to minimize distortion of the optical image projected onto the photosensitive film. When the light source is an ArF excimer laser (wavelength; 193 nm), it is preferable to use water from the viewpoints of availability and ease of handling in addition to the above-described viewpoints.
Further, a medium having a refractive index of 1.5 or more can be used in that the refractive index can be further improved. This medium may be an aqueous solution or an organic solvent.

When water is used as the immersion liquid, the photosensitive film on the wafer is not dissolved and the influence on the optical coating on the lower surface of the lens element is ignored in order to reduce the surface tension of the water and increase the surface activity. A possible additive (liquid) may be added in a small proportion. The additive is preferably an aliphatic alcohol having a refractive index substantially equal to that of water, and specifically includes methyl alcohol, ethyl alcohol, isopropyl alcohol and the like. By adding an alcohol having a refractive index substantially equal to that of water, even if the alcohol component in water evaporates and the content concentration changes, an advantage that the change in the refractive index of the entire liquid can be made extremely small can be obtained. On the other hand, when an opaque material or impurities whose refractive index is significantly different from that of water are mixed in with 193 nm light, the optical image projected on the photosensitive film is distorted. preferable. Further, pure water filtered through an ion exchange filter or the like may be used.

The electrical resistance of water as the immersion liquid is preferably 18.3 MQcm or more, the TOC (organic substance concentration) is preferably 20 ppb or less, and deaeration treatment is preferably performed.
Moreover, it is possible to improve lithography performance by increasing the refractive index of the immersion liquid. From such a viewpoint, an additive for increasing the refractive index may be added to water, or heavy water (D ₂ O) may be used instead of water.

[Photosensitive composition]
The photosensitive composition used in the pattern forming method of the present invention is not particularly limited, but generally contains an acid generator, a resin, and an organic solvent, and preferably further contains an acid diffusibility inhibitor and a surface activity. An agent may be contained, and other additives may be contained.

<1. Acid generator>
As an acid generator, photo-initiator of photocation polymerization, photo-initiator of photo-radical polymerization, photo-decoloring agent of dyes, photo-discoloring agent, or irradiation with actinic ray or radiation used for micro-resist etc. Known compounds that generate acids and mixtures thereof can be appropriately selected and used.

  Examples thereof include diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imide sulfonates, oxime sulfonates, diazodisulfones, disulfones, and o-nitrobenzyl sulfonates.

  Further, a group that generates an acid upon irradiation with these actinic rays or radiation, or a compound in which a compound is introduced into the main chain or side chain of the polymer, such as US Pat. No. 3,849,137, German Patent No. No. 3914407, JP-A 63-26653, JP-A 55-164824, JP-A 62-69263, JP-A 63-146038, JP-A 63-163452, The compounds described in JP-A-62-153853 and JP-A-63-146029 can be used.

  Furthermore, compounds capable of generating an acid by light described in US Pat. No. 3,779,778, European Patent 126,712, etc. can also be used.

  Preferred compounds among the acid generators include compounds represented by the following general formulas (ZI), (ZII), and (ZIII).

In the general formula (ZI),
R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents an organic group.
The carbon number of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ is generally 1 to 30, preferably 1
~ 20.
Two of R _{201 to} R ₂₀₃ may be bonded to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group. The two of the group formed by bonding of the R ₂₀₁ to R _203, there can be mentioned an alkylene group (e.g., butylene, pentylene).
Z ⁻ represents a non-nucleophilic anion.

Examples of the non-nucleophilic anion as Z ⁻ include a sulfonate anion, a carboxylate anion, a sulfonylimide anion, a bis (alkylsulfonyl) imide anion, and a tris (alkylsulfonyl) methyl anion.

  A non-nucleophilic anion is an anion that has an extremely low ability to cause a nucleophilic reaction, and is an anion that can suppress degradation over time due to an intramolecular nucleophilic reaction. Thereby, the temporal stability of the photosensitive composition is improved.

  Examples of the sulfonate anion include an aliphatic sulfonate anion, an aromatic sulfonate anion, and a camphor sulfonate anion.

  Examples of the carboxylate anion include an aliphatic carboxylate anion, an aromatic carboxylate anion, and an aralkylcarboxylate anion.

  The aliphatic moiety in the aliphatic sulfonate anion may be an alkyl group or a cycloalkyl group, preferably an alkyl group having 1 to 30 carbon atoms and a cycloalkyl group having 3 to 30 carbon atoms such as methyl. Group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group , Tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, adamantyl group, norbornyl group, bornyl group and the like.

  The aromatic group in the aromatic sulfonate anion is preferably an aryl group having 6 to 14 carbon atoms, such as a phenyl group, a tolyl group, and a naphthyl group.

The alkyl group, cycloalkyl group and aryl group in the aliphatic sulfonate anion and aromatic sulfonate anion may have a substituent. Examples of the substituent of the alkyl group, cycloalkyl group, and aryl group in the aliphatic sulfonate anion and aromatic sulfonate anion include, for example, a nitro group, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), carboxyl group , Hydroxyl group, amino group, cyano group, alkoxy group (preferably having 1 to 15 carbon atoms), cycloalkyl group (preferably having 3 to 15 carbon atoms), aryl group (preferably having 6 to 14 carbon atoms), alkoxycarbonyl group ( Preferably 2 to 7 carbon atoms, acyl group (preferably 2 to 12 carbon atoms), alkoxycarbonyloxy group (preferably 2 to 7 carbon atoms), alkylthio group (preferably 1 to 15 carbon atoms), alkylsulfonyl group (Preferably having 1 to 15 carbon atoms), alkyliminosulfonyl group (preferably having 2 to 15 carbon atoms), aryl Ruoxysulfonyl group (preferably having 6 to 20 carbon atoms), alkylaryloxysulfonyl group (preferably having 7 to 20 carbon atoms), cycloalkylaryloxysulfonyl group (preferably having 10 to 20 carbon atoms), alkyloxyalkyloxy group (Preferably having 5 to 20 carbon atoms), a cycloalkylalkyloxyalkyloxy group (preferably having 8 to 20 carbon atoms), and the like. About the aryl group and ring structure which each group has, an alkyl group (preferably C1-C15) can further be mentioned as a substituent.

  Examples of the aliphatic moiety in the aliphatic carboxylate anion include the same alkyl group and cycloalkyl group as in the aliphatic sulfonate anion.

  Examples of the aromatic group in the aromatic carboxylate anion include the same aryl group as in the aromatic sulfonate anion.

  The aralkyl group in the aralkyl carboxylate anion is preferably an aralkyl group having 6 to 12 carbon atoms, such as benzyl group, phenethyl group, naphthylmethyl group, naphthylethyl group, naphthylbutyl group, and the like.

  The alkyl group, cycloalkyl group, aryl group and aralkyl group in the aliphatic carboxylate anion, aromatic carboxylate anion and aralkylcarboxylate anion may have a substituent. Examples of the substituent of the alkyl group, cycloalkyl group, aryl group and aralkyl group in the aliphatic carboxylate anion, aromatic carboxylate anion and aralkylcarboxylate anion include, for example, the same halogen atom and alkyl as in the aromatic sulfonate anion Group, cycloalkyl group, alkoxy group, alkylthio group and the like.

  Examples of the sulfonylimide anion include saccharin anion.

  The alkyl group in the bis (alkylsulfonyl) imide anion and tris (alkylsulfonyl) methyl anion is preferably an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, An isobutyl group, a sec-butyl group, a pentyl group, a neopentyl group, and the like can be given. Examples of substituents for these alkyl groups include halogen atoms, alkyl groups substituted with halogen atoms, alkoxy groups, alkylthio groups, alkyloxysulfonyl groups, aryloxysulfonyl groups, cycloalkylaryloxysulfonyl groups, and the like. Alkyl groups substituted with fluorine atoms are preferred.

  Examples of other non-nucleophilic anions include fluorinated phosphorus, fluorinated boron, and fluorinated antimony.

Examples of the non-nucleophilic anion of Z ⁻ include an aliphatic sulfonate anion in which the α-position of the sulfonic acid is substituted with a fluorine atom, an aromatic sulfonate anion substituted with a fluorine atom or a group having a fluorine atom, and an alkyl group. A bis (alkylsulfonyl) imide anion substituted with a fluorine atom and a tris (alkylsulfonyl) methide anion wherein an alkyl group is substituted with a fluorine atom are preferred. The non-nucleophilic anion is more preferably a perfluoroaliphatic sulfonic acid anion having 4 to 8 carbon atoms, a benzenesulfonic acid anion having a fluorine atom, still more preferably a nonafluorobutanesulfonic acid anion, a perfluorooctanesulfonic acid anion, It is a pentafluorobenzenesulfonic acid anion and 3,5-bis (trifluoromethyl) benzenesulfonic acid anion.

Examples of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ include the corresponding groups in the compounds (ZI-1), (ZI-2) and (ZI-3) described later.

In addition, the compound which has two or more structures represented by general formula (ZI) may be sufficient. For example, the general formula at least one of R ₂₀₁ to R ₂₀₃ of a compound represented by (ZI), the structures attached to at least one of R ₂₀₁ to R ₂₀₃ of another compound represented by formula (ZI) It may be a compound.

  More preferred (ZI) components include compounds (ZI-1), (ZI-2), (ZI-3) and (ZI-4) described below.

The compound (ZI-1) is at least one of the aryl groups R ₂₀₁ to R ₂₀₃ in formula (ZI), arylsulfonium compounds, namely, compounds containing an arylsulfonium as a cation.

In the arylsulfonium compound, all of R _{201 to} R ₂₀₃ may be an aryl group, or a part of R _{201 to} R ₂₀₃ may be an aryl group with the remaining being an alkyl group or a cycloalkyl group.

  Examples of the arylsulfonium compound include triarylsulfonium compounds, diarylalkylsulfonium compounds, aryldialkylsulfonium compounds, diarylcycloalkylsulfonium compounds, and aryldicycloalkylsulfonium compounds.

  The aryl group of the arylsulfonium compound is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The aryl group may be an aryl group having a heterocyclic structure having an oxygen atom, a nitrogen atom, a sulfur atom or the like. Examples of the aryl group having a heterocyclic structure include a pyrrole residue (a group formed by losing one hydrogen atom from pyrrole) and a furan residue (a group formed by losing one hydrogen atom from furan). Groups), thiophene residues (groups formed by the loss of one hydrogen atom from thiophene), indole residues (groups formed by the loss of one hydrogen atom from indole), benzofuran residues ( A group formed by losing one hydrogen atom from benzofuran), a benzothiophene residue (a group formed by losing one hydrogen atom from benzothiophene), and the like. When the arylsulfonium compound has two or more aryl groups, the two or more aryl groups may be the same or different.

  The alkyl group or cycloalkyl group that the arylsulfonium compound has as necessary is preferably a linear or branched alkyl group having 1 to 15 carbon atoms and a cycloalkyl group having 3 to 15 carbon atoms, such as a methyl group, Examples thereof include an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a t-butyl group, a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.

Aryl group, alkyl group of R ₂₀₁ to R _203, cycloalkyl group, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (for example, 6 to 14 carbon atoms) , An alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, or a phenylthio group may be substituted. Preferred substituents are linear or branched alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 3 to 12 carbon atoms, and linear, branched or cyclic alkoxy groups having 1 to 12 carbon atoms, more preferably carbon. These are an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms. The substituent may be substituted with any one of the three R _{201 to} R ₂₀₃ , or may be substituted with all three. When R _{201 to} R ₂₀₃ are an aryl group, the substituent is preferably substituted at the p-position of the aryl group.

Next, the compound (ZI-2) will be described.
Compound (ZI-2) is a compound in which R _{201 to} R ₂₀₃ in formula (ZI) each independently represents an organic group having no aromatic ring. Here, the aromatic ring includes an aromatic ring containing a hetero atom.

The organic group having no aromatic ring as R ₂₀₁ to R ₂₀₃ generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.

R _{201 to} R ₂₀₃ are each independently preferably an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group, more preferably a linear or branched 2-oxoalkyl group, 2-oxocycloalkyl group, alkoxy group. A carbonylmethyl group, particularly preferably a linear or branched 2-oxoalkyl group.

The alkyl group and cycloalkyl group of R ₂₀₁ to R _203, preferably a linear or branched alkyl group having 1 to 10 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group, pentyl group), carbon Examples thereof include cycloalkyl groups of several 3 to 10 (cyclopentyl group, cyclohexyl group, norbornyl group). More preferred examples of the alkyl group include a 2-oxoalkyl group and an alkoxycarbonylmethyl group. More preferred examples of the cycloalkyl group include a 2-oxocycloalkyl group.

The 2-oxoalkyl group may be either linear or branched, and a group having> C = O at the 2-position of the above alkyl group is preferable.
The 2-oxocycloalkyl group is preferably a group having> C═O at the 2-position of the cycloalkyl group.

  The alkoxy group in the alkoxycarbonylmethyl group is preferably an alkoxy group having 1 to 5 carbon atoms (methoxy group, ethoxy group, propoxy group, butoxy group, pentoxy group).

R _{201 to} R ₂₀₃ may be further substituted with a halogen atom, an alkoxy group (for example, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

  The compound (ZI-3) is a compound represented by the following general formula (ZI-3), and is a compound having a phenacylsulfonium salt structure.

In general formula (ZI-3),
R _1c to R _5c each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group or a halogen atom.
R _6c and R _7c each independently represents a hydrogen atom, an alkyl group or a cycloalkyl group.
R _x and R _y independently represents an alkyl group, a cycloalkyl group, an allyl group or a vinyl group.

Any two or more of R _{1c to} R _5c , R _6c and R _7c , and R _x and R _y may be bonded to each other to form a ring structure, and this ring structure includes an oxygen atom and a sulfur atom. , An ester bond and an amide bond may be included. Examples of the group formed by combining any two or more of R _{1c to} R _5c , R _6c and R _7c , and R _x and R _y include a butylene group and a pentylene group.

Zc ⁻ represents a non-nucleophilic anion, and examples thereof include the same non-nucleophilic anion as Z ^{− in} formula (ZI).

The alkyl group as R _1c to R _7c may be linear or branched may be any of, for example, alkyl group having 1 to 20 carbon atoms, preferably 1 to 12 linear or branched alkyl group having a carbon number ( Examples thereof include a methyl group, an ethyl group, a linear or branched propyl group, a linear or branched butyl group, and a linear or branched pentyl group. Examples of the cycloalkyl group include cyclohexane having 3 to 8 carbon atoms. An alkyl group (for example, a cyclopentyl group, a cyclohexyl group) can be mentioned.

The alkoxy group as R _{1c to} R _{5c may} be linear, branched or cyclic, for example, an alkoxy group having 1 to 10 carbon atoms, preferably a linear or branched alkoxy group having 1 to 5 carbon atoms. (For example, methoxy group, ethoxy group, linear or branched propoxy group, linear or branched butoxy group, linear or branched pentoxy group), C3-C8 cyclic alkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group) ).

Preferably, any of R _{1c to} R _5c is a linear or branched alkyl group, a cycloalkyl group, or a linear, branched or cyclic alkoxy group, and more preferably the sum of the carbon number of R _{1c to} R _5c. Is 2-15. Thereby, solvent solubility improves more and generation | occurrence | production of a particle is suppressed at the time of a preservation | save.

_Examples of the alkyl group and cycloalkyl group as R _x and R _y include the same alkyl group and cycloalkyl group as in R _{1c to} R _7c , such as a 2-oxoalkyl group, a 2-oxocycloalkyl group, an alkoxy group. A carbonylmethyl group is more preferred.

Examples of the 2-oxoalkyl group and 2-oxocycloalkyl group include a group having> C═O at the 2-position of the alkyl group or cycloalkyl group as R _{1c to} R _7c .

Examples of the alkoxy group in the alkoxycarbonylmethyl group include the same alkoxy groups as in R _{1c to} R _5c .

R _x and R _y are preferably an alkyl group or cycloalkyl group having 4 or more carbon atoms, more preferably 6 or more, and still more preferably 8 or more alkyl groups or cycloalkyl groups.

  The compound (ZI-4) is a compound represented by the following general formula (ZI-4).

In general formula (ZI-4),
R ₁₃ represents a hydrogen atom, a fluorine atom, a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, or an alkoxycarbonyl group.
When a plurality of R ₁₄ are present, each independently represents an alkyl group, a cycloalkyl group, an alkoxy group, an alkylsulfonyl group, or a cycloalkylsulfonyl group.
R ₁₅ each independently represents an alkyl group or a cycloalkyl group. Two R ₁₅ may combine with each other to form a ring.
l represents an integer of 0-2.
r represents an integer of 0 to 10.
Z ⁻ represents a non-nucleophilic anion, and examples thereof include the same non-nucleophilic anion as Z ^{− in} formula (ZI).

In formula _(ZI-4), the alkyl group of R _{13, R 14} and _{R 15,} may be linear or branched, preferably has 1 to 10 carbon atoms, a methyl group, an ethyl radical, n -Propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, n-pentyl group, neopentyl group, n-hexyl group, n-heptyl group, n -An octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group etc. can be mentioned. Of these alkyl groups, a methyl group, an ethyl group, an n-butyl group, a t-butyl group, and the like are preferable.
Examples of the cycloalkyl group of R ₁₃ , R ₁₄ and R ₁₅ include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclododecanyl, cyclobenenyl, cyclohexenyl, cyclooctadienyl and the like. In particular, cyclopropyl, cyclopentyl, cyclohexyl and cyclooctyl are preferred.

The alkoxy group of R ₁₃ and R ₁₄ is linear or branched and preferably has 1 to 10 carbon atoms, such as methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n -Butoxy group, 2-methylpropoxy group, 1-methylpropoxy group, t-butoxy group, n-pentyloxy group, neopentyloxy group, n-hexyloxy group, n-heptyloxy group, n-octyloxy group, 2-ethylhexyloxy group, n-nonyloxy group, n-decyloxy group and the like can be mentioned. Of these alkoxy groups, a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, and the like are preferable.

The alkoxycarbonyl group for R ₁₃ is linear or branched and preferably has 2 to 11 carbon atoms, and examples thereof include an alkoxycarbonyl group corresponding to the alkoxy group exemplified as R ₁₃ . Of these alkoxycarbonyl groups, a methoxycarbonyl group, an ethoxycarbonyl group, an n-butoxycarbonyl group, and the like are preferable.

The alkylsulfonyl group and cycloalkylsulfonyl group of R ₁₄ are linear, branched, or cyclic, and preferably those having 1 to 10 carbon atoms. For example, the alkyl group or cycloalkylsulfonyl group exemplified as R ₁₃ And alkylsulfonyl groups and cycloalkylsulfonyl groups corresponding to.
Of these alkylsulfonyl groups and cycloalkylsulfonyl groups, a methanesulfonyl group, an ethanesulfonyl group, an n-propanesulfonyl group, an n-butanesulfonyl group, a cyclopentanesulfonyl group, a cyclohexanesulfonyl group, and the like are preferable.

  l is preferably 0 or 1, and more preferably 1. As r, 0-2 are preferable.

Examples of the substituent that each group of R ₁₃ , R ₁₄ , and R ₁₅ may have include a halogen atom (for example, a fluorine atom), a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkoxy group, and an alkoxy group. Examples thereof include an alkyl group, an alkoxycarbonyl group, and an alkoxycarbonyloxy group.
Examples of the alkoxy group include methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, 2-methylpropoxy group, 1-methylpropoxy group, t-butoxy group, cyclopentyloxy group, Examples thereof include a linear, branched or cyclic alkoxy group having 1 to 20 carbon atoms such as a cyclohexyloxy group.
Examples of the alkoxyalkyl group include straight chain having 2 to 21 carbon atoms such as methoxymethyl group, ethoxymethyl group, 1-methoxyethyl group, 2-methoxyethyl group, 1-ethoxyethyl group, and 2-ethoxyethyl group. Examples thereof include a chain, branched or cyclic alkoxyalkyl group.
Examples of the alkoxycarbonyl group include linear, branched or cyclic alkoxycarbonyl groups having 2 to 21 carbon atoms. Examples of the alkoxycarbonyl group include alkoxycarbonyl groups corresponding to those exemplified above. Can do.
Examples of the alkoxycarbonyloxy group include linear, branched or cyclic alkoxycarbonyloxy groups having 2 to 21 carbon atoms, and alkoxycarbonyloxy corresponding to those exemplified as the alkoxy group. The group can be mentioned.

As the ring structure that two R ₁₅ may be bonded to each other, a 5- or 6-membered ring, particularly preferably a 5-membered ring (that is, a 5-membered ring together with the sulfur atom in the general formula (ZI-4) (that is, A group that forms a tetrahydrothiophene ring) is desirable. Examples of the substituent for the divalent group include a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkoxy group, an alkoxyalkyl group, an alkoxycarbonyl group, and an alkoxycarbonyloxy group. R ₁₅ in the general formula (ZI-4) is preferably a methyl group, an ethyl group, a divalent group in which two R ₁₅ are bonded to each other to form a tetrahydrothiophene ring structure together with a sulfur atom.
The alkyl group, cycloalkyl group, alkoxy group, or alkoxycarbonyl group of R _13, the alkyl group, cycloalkyl group, alkoxy group, alkylsulfonyl group, and cycloalkylsulfonyl group of R ₁₄ may be substituted as described above. The substituent is preferably a hydroxyl group, an alkoxy group, an alkoxycarbonyl group, or a halogen atom (particularly a fluorine atom).

  Below, the preferable specific example of the cation in the compound represented by general formula (ZI-4) is shown.

In the general formulas (ZII) and (ZIII),
R ₂₀₄ to R ₂₀₇ each independently represents an aryl group, an alkyl group or a cycloalkyl group.

Phenyl group and a naphthyl group are preferred as the aryl group of R ₂₀₄ to R _207, more preferably a phenyl group. Aryl group R ₂₀₄ to R ₂₀₇ represents an oxygen atom, a nitrogen atom, may be an aryl group having a heterocyclic structure having a sulfur atom and the like. Examples of the aryl group having a heterocyclic structure include a pyrrole residue (a group formed by losing one hydrogen atom from pyrrole) and a furan residue (a group formed by losing one hydrogen atom from furan). Groups), thiophene residues (groups formed by the loss of one hydrogen atom from thiophene), indole residues (groups formed by the loss of one hydrogen atom from indole), benzofuran residues ( A group formed by losing one hydrogen atom from benzofuran), a benzothiophene residue (a group formed by losing one hydrogen atom from benzothiophene), and the like.

The alkyl group and cycloalkyl group in R ₂₀₄ to R _207, preferably a linear or branched alkyl group having 1 to 10 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group, pentyl group), carbon Examples thereof include cycloalkyl groups of several 3 to 10 (cyclopentyl group, cyclohexyl group, norbornyl group).

Aryl group, alkyl group of R ₂₀₄ to R _207, cycloalkyl groups may have a substituent. Aryl group, alkyl group of R ₂₀₄ to R _207, the cycloalkyl group substituent which may be possessed by, for example, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms ), An aryl group (for example, having 6 to 15 carbon atoms), an alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, and a phenylthio group.

Z ⁻ represents a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of Z ^{− in} formula (ZI).

Examples of the acid generator further include compounds represented by the following general formulas (ZIV), (ZV), and (ZVI).

In general formulas (ZIV) to (ZVI),
Ar ₃ and Ar ₄ each independently represents an aryl group.
R ₂₀₈ , R ₂₀₉ and R ₂₁₀ each independently represents an alkyl group, a cycloalkyl group or an aryl group.
A represents an alkylene group, an alkenylene group or an arylene group.

Among the acid generators, compounds represented by the general formulas (ZI) to (ZIII) are more preferable.
Further, the acid generator is preferably a compound that generates an acid having one sulfonic acid group or imide group, more preferably a compound that generates monovalent perfluoroalkanesulfonic acid, or a monovalent fluorine atom or fluorine atom. A compound that generates an aromatic sulfonic acid substituted with a group that contains a monovalent fluorine atom or an imido acid that is substituted with a group containing a fluorine atom, and even more preferably, a fluorinated compound It is a sulfonium salt of a substituted alkanesulfonic acid, a fluorine-substituted benzenesulfonic acid, a fluorine-substituted imide acid or a fluorine-substituted methide acid. The acid generator that can be used is particularly preferably a fluorinated substituted alkane sulfonic acid, a fluorinated substituted benzene sulfonic acid or a fluorinated substituted imido acid whose pKa of the generated acid is pKa = -1 or less, and the sensitivity is improved. .

  Among acid generators, particularly preferred examples are given below.

  Moreover, the compound represented by the following general formula (N1) can be mentioned as a preferable compound in an acid generator.

In formula (N1),
R ¹ is —R ⁵ , —COR ⁶ , —COOR ⁶ , —CON (R ⁶ ) (R ⁷ ), —N (R ⁶ ) (R ⁷ ), —N (R ⁶ ) CO (R ⁷ ), — ^{N (R 6) COOR 7,} -N (COR 6) (COR 7), - SR 6, -SOR 6, represents -SO ₂ R ⁶ or -SO ₂ (oR ^6), wherein R ¹ there are a plurality of In the case where the R ¹ is contained in the norbornane structure, they may form a ring together with the carbon atom, and when two or more R ¹ are present, The above R ¹ may be bonded to each other to form a ring, and R ⁵ is a linear, branched or cyclic monovalent hydrocarbon group having 1 to 30 carbon atoms, or 6 to 30 carbon atoms. An aryl group or a monovalent heterocyclic organic group having 4 to 30 atoms, wherein R ⁶ and R ⁷ are each independently a hydrogen atom, a linear or branched one having 1 to 30 carbon atoms. Or a cyclic monovalent hydrocarbon group, an aryl group having 6 to 30 carbon atoms, or a monovalent heterocyclic organic group having 4 to 30 atoms, wherein R ² , R ³ and R ⁴ are independently hydrogen. Represents an atom or a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, k is an integer of 0 or more, n is an integer of 0 to 5, M ⁺ represents a monovalent onium cation, For example, the onium cation in the compound represented by the general formula (ZI) or (ZII) can be given.

  Specific examples of the compound represented by the formula (N1) include, for example, the onium cation in the above-described specific examples z1 to z91 of the compound represented by the general formula (ZI) or (ZII) and the norbornane in the formula (N1). Examples of the structure include compounds having the following.

An acid generator can be used individually by 1 type or in combination of 2 or more types.
The content of the acid generator in the photosensitive composition is determined based on the total solid content of the photosensitive composition.
1-40 mass% is preferable, More preferably, it is 0.5-25 mass%, More preferably, it is 1-20 mass%.

<2. Resin>
As the resin contained in the photosensitive composition used in the pattern forming method of the present invention, a resin whose solubility in an alkaline developer increases by the action of an acid (hereinafter also referred to as resin (A)), the main chain or side chain of the resin Alternatively, a resin having a group capable of decomposing by the action of an acid to generate an alkali-soluble group (hereinafter also referred to as “acid-decomposing group”) is preferably used in both the main chain and the side chain.
The alkali-soluble group is not particularly limited as long as it is a group that dissociates and becomes an ion in an alkali developer, but a phenolic hydroxyl group, a carboxyl group, a fluorinated alcohol group, a sulfonic acid group, a sulfonamide group, a sulfonylimide group, (Alkylsulfonyl) (alkylcarbonyl) methylene group, (alkylsulfonyl) (alkylcarbonyl) imide group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) ) Imido group, tris (alkylcarbonyl) methylene group, tris (alkylsulfonyl) methylene group and the like.
Preferred alkali-soluble groups include carboxyl groups, fluorinated alcohol groups (preferably hexafluoroisopropanol), and sulfonic acid groups.
A preferred group as the acid-decomposable group is a group obtained by substituting the hydrogen atom of these alkali-soluble groups with a group capable of leaving with an acid.
Examples of the group leaving with an acid include -C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), -C (R ₃₆ ) (R ₃₇ ) (OR ₃₉ ), -C (R ₀₁ ) (R ₀₂ ). ) (OR ₃₉ ) and the like.
In the formula, R _{36 to} R ₃₉ each independently represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R ₃₆ and R ₃₇ may be bonded to each other to form a ring.
R _{01 and} R ₀₂ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkenyl group.
The acid-decomposable group is preferably a cumyl ester group, an enol ester group, an acetal ester group, a tertiary alkyl ester group or the like. More preferably, it is a tertiary alkyl ester group.

  The repeating unit having an acid-decomposable group that can be contained in the resin (A) is preferably a repeating unit represented by the following general formula (AI).

In general formula (AI),
Xa ₁ represents a hydrogen atom, a methyl group which may have a substituent, or a group represented by —CH ₂ —R ₉ . R ₉ represents a hydroxyl group or a monovalent organic group, and examples of the monovalent organic group include an alkyl group having 5 or less carbon atoms and an acyl group, preferably an alkyl group having 3 or less carbon atoms, More preferred is a methyl group. Xa ₁ preferably represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.
T represents a single bond or a divalent linking group.
Rx _{1 to} Rx ₃ each independently represents an alkyl group (straight or branched) or a cycloalkyl group (monocyclic or polycyclic).
Two of Rx _{1 to} Rx ₃ may combine to form a cycloalkyl group (monocyclic or polycyclic).

Examples of the divalent linking group for T include an alkylene group, —COO—Rt— group, —O—Rt— group, and the like. In the formula, Rt represents an alkylene group or a cycloalkylene group.
T is preferably a single bond or a —COO—Rt— group. Rt is preferably an alkylene group having 1 to 5 carbon atoms, more preferably a —CH ₂ — group or a — (CH ₂ ) ₃ — group.
The alkyl group of Rx _{1 to} Rx ₃ is preferably an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or a t-butyl group.
Examples of the cycloalkyl group represented by Rx _{1 to} Rx ₃ include monocyclic cycloalkyl groups such as cyclopentyl group and cyclohexyl group, polycyclic cycloalkyl groups such as norbornyl group, tetracyclodecanyl group, tetracyclododecanyl group, and adamantyl group. Groups are preferred.
Examples of the cycloalkyl group formed by combining two of Rx _{1 to} Rx ₃ include a monocyclic cycloalkyl group such as a cyclopentyl group and a cyclohexyl group, a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, an adamantyl group A polycyclic cycloalkyl group such as a group is preferred. A monocyclic cycloalkyl group having 5 to 6 carbon atoms is particularly preferable.
An embodiment in which Rx ₁ is a methyl group or an ethyl group, and Rx ₂ and Rx ₃ are combined to form the above-described cycloalkyl group is preferred.
Each of the above groups may have a substituent. Examples of the substituent include an alkyl group (1 to 4 carbon atoms), a halogen atom, a hydroxyl group, an alkoxy group (1 to 4 carbon atoms), a carboxyl group, An alkoxycarbonyl group (C2-C6) etc. are mentioned, C8 or less is preferable.

  The content of the repeating unit having an acid-decomposable group as a total is preferably 20 to 70 mol%, more preferably 30 to 50 mol%, based on all repeating units in the resin.

Although the specific example of the repeating unit which has a preferable acid-decomposable group is shown below, this invention is not limited to this.
In specific examples, Rx and Xa ₁ represent a hydrogen atom, CH ₃ , CF ₃ , or CH ₂ OH. Rxa and Rxb each represents an alkyl group having 1 to 4 carbon atoms. Z represents a substituent containing a polar group, for example, a hydroxyl group, a cyano group, an amino group, an alkylamide group or a sulfonamide group, or a linear or branched alkyl group or cyclohexane having a group selected from these groups. An alkyl group is mentioned, and when there are a plurality of alkyl groups, each is independent. p represents 0 or a positive integer.

In the following chemical structural formula, Xa ₁ is synonymous with Rx in the chemical structural formula, and Z and p are synonymous with Z and p in the chemical structural formula.

  The resin (A) is a resin having at least one of the repeating unit represented by the general formula (1) and the repeating unit represented by the general formula (2) as the repeating unit represented by the general formula (AI). More preferably.

In formulas (1) and (2),
R ₁ and R ₃ each independently represents a hydrogen atom, an optionally substituted methyl group or a group represented by —CH ₂ —R ₉ . R ₉ represents a hydroxyl group or a monovalent organic group.
R ₂ , R ₄ , R ₅ and R ₆ each independently represents an alkyl group or a cycloalkyl group.
R represents an atomic group necessary for forming an alicyclic structure together with a carbon atom.

R ₁ preferably represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.

The alkyl group in R ₂ may be linear or branched, and may have a substituent.
The cycloalkyl group in R ₂ may be monocyclic or polycyclic and may have a substituent.
R ₂ is preferably an alkyl group, more preferably one having 1 to 10 carbon atoms, still more preferably 1 to 5, and examples thereof include a methyl group and an ethyl group.

  R represents an atomic group necessary for forming an alicyclic structure together with a carbon atom. The alicyclic structure formed by R is preferably a monocyclic alicyclic structure, and the carbon number thereof is preferably 3 to 7, and more preferably 5 or 6.

R ₃ is preferably a hydrogen atom or a methyl group, more preferably a methyl group.
The alkyl group in R ₄ , R ₅ and R ₆ may be linear or branched and may have a substituent. As the alkyl group, those having 1 to 4 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group and t-butyl group are preferable.
The cycloalkyl group in R ₄ , R ₅ and R ₆ may be monocyclic or polycyclic and may have a substituent. The cycloalkyl group is preferably a monocyclic cycloalkyl group such as a cyclopentyl group or a cyclohexyl group, or a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group or an adamantyl group.

  The repeating unit represented by the general formula (2) is preferably a repeating unit represented by the following general formula (2-1).

In formula (2-1),
R < ₃ > -R < ₅ > is synonymous with the thing in General formula (2).
R ₁₀ represents a substituent containing a polar group. When a plurality of R ₁₀ are present, they may be the same as or different from each other. Examples of the substituent containing a polar group include a hydroxyl group, a cyano group, an amino group, an alkylamide group or a sulfonamide group, or a linear or branched alkyl group or cycloalkyl group having a group selected from these groups. An alkyl group having a hydroxyl group is preferable. A branched alkyl group having a hydroxyl group is more preferable, and an isopropyl group is particularly preferable as the branched alkyl group.
p represents an integer of 0 to 15. p is preferably 0 to 2, more preferably 0 or 1.

In the resin (A), preferred combinations of repeating units whose alkali solubility is increased by the action of at least two acids are listed below, but the present invention is not limited thereto. R in the following is each independently H or CH ₃ .

The resin (A) preferably contains a repeating unit having a lactone group.
Any lactone group can be used as long as it has a lactone structure, but it is preferably a 5- to 7-membered ring lactone structure, and forms a bicyclo structure or a spiro structure in the 5- to 7-membered ring lactone structure. The other ring structure is preferably condensed. It is more preferable to have a repeating unit having a lactone structure represented by any of the following general formulas (LC1-1) to (LC1-17). The lactone structure may be directly bonded to the main chain. Preferred lactone structures are (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13), (LC1-14), and (LC1-17). By using this lactone structure, LWR and development defects are improved.

The lactone structure moiety may or may not have a substituent (Rb ₂ ). Preferred substituents (Rb ₂ ) include an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, and a carboxyl group. , Halogen atom, hydroxyl group, cyano group, acid-decomposable group and the like. More preferably, they are a C1-C4 alkyl group, a cyano group, and an acid-decomposable group. n ₂ represents an integer of 0-4. When n ₂ is 2 or more, a plurality of substituents (Rb ₂ ) may be the same or different, and a plurality of substituents (Rb ₂ ) may be bonded to form a ring. .

  As the repeating unit having a lactone structure, a repeating unit represented by the following general formula (AII) is also preferable.

In general formula (AII),
Rb ₀ represents a hydrogen atom, a halogen atom or an optionally substituted alkyl group having 1 to 4 carbon atoms. Preferred substituents that the alkyl group represented by Rb ₀ may have include a hydroxyl group and a halogen atom. Examples of the halogen atom for Rb ₀ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Rb ₀ is preferably a hydrogen atom, a methyl group, a hydroxymethyl group, or a trifluoromethyl group, and particularly preferably a hydrogen atom or a methyl group.
Ab represents a single bond, an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, or a divalent linking group obtained by combining these. Preferably a single bond, -Ab ₁ -CO ₂ - is a divalent linking group represented by.
Ab ₁ is a linear, branched alkylene group, monocyclic or polycyclic cycloalkylene group, preferably a methylene group, an ethylene group, a cyclohexylene group, an adamantylene group or a norbornylene group.
V represents a group having a structure represented by any one of the general formulas (LC1-1) to (LC1-17).

  Specific examples of the repeating unit having a lactone group are listed below, but the present invention is not limited thereto.

  Particularly preferred repeating units having a lactone group include the following repeating units. By selecting an optimal lactone group, the pattern profile and the density dependency are improved.

The resin (A) has a lactone group represented by the following general formula (3) in order to achieve a glass transition temperature in the range of the glass transition temperature of the resin <the heating temperature used in the post-baking step + 20 ° C. It is preferable to include a repeating unit.
The repeating unit having a lactone group represented by the general formula (3) is effective for lowering the Tg of the resin, and in particular, the Tg can be controlled to 175 ° C. or lower. And the repeating unit which has a lactone group represented by General formula (3) can provide resin with low Tg which does not degrade LWR and EL. The content of the repeating unit having a lactone group represented by the general formula (3) is preferably 15 to 60 mol%, more preferably 20 to 50 mol%, still more preferably based on all repeating units in the resin (A). 30 to 50 mol%.
The Tg of the resin is preferably 80 ° C to 250 ° C, more preferably 100 ° C to 240 ° C, and most preferably 135 ° C to 220 ° C.

In formula (3),
A represents an ester bond (—COO—) or an amide bond (—CONH—).
R ₀ represents an alkylene group, a cycloalkylene group, or a combination thereof independently when there are a plurality of R ₀ .
Z is independently an ether bond, an ester bond, an amide bond, a urethane bond, or a urea bond when there are a plurality of Z.
R ₈ represents a monovalent organic group having a lactone structure.
n is the repeating number of the structure represented by —R ₀ —Z— in the repeating unit represented by the formula (3), and represents an integer of 1 to 5.
R ₇ represents a hydrogen atom, a methyl group or a group represented by —CH ₂ —R ₉ . R ₉ represents a monovalent organic group

The alkylene group and cycloalkylene group represented by R ₀ may have a substituent.
Z is preferably an ether bond or an ester bond, and particularly preferably an ester bond.

R ₇ is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group,
A methyl group is most preferred. The group in R ₇ may be substituted. Examples of the substituent include halogen atoms such as fluorine atom, chlorine atom and bromine atom, mercapto group, hydroxy group, methoxy group, ethoxy group, isopropoxy group, t-butoxy group. Groups, alkoxy groups such as benzyloxy group, and acetoxy groups such as acetyl group and propionyl group.
Preferable chain alkylene group in R ₀ is preferably a chain alkylene having 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and examples thereof include a methylene group, an ethylene group, and a propylene group. Preferred cycloalkylene is cycloalkylene having 4 to 20 carbon atoms, and examples thereof include cyclohexylene, cyclopentylene, norbornylene, adamantylene and the like. In order to exhibit the effects of the present invention, a chain alkylene group is preferable, and a methylene group is particularly preferable.

The substituent having a lactone structure represented by R ₈ is not limited as long as it has a lactone structure, and specific examples include lactones represented by general formulas (LC1-1) to (LC1-17). The structure is mentioned, Of these, the structure represented by (LC1-4) is particularly preferable. Further, n ₂ in (LC1-1) to (LC1-17) is more preferably 2 or less.
R ₈ is preferably a monovalent organic group having an unsubstituted lactone structure or a monovalent organic group having a lactone structure having a methyl group, a cyano group or an alkoxycarbonyl group as a substituent. A monovalent organic group having a lactone structure (cyanolactone) as is more preferable.

Specific examples of the repeating unit having a group having a lactone structure represented by the general formula (3) are shown below, but the present invention is not limited thereto.
In the following specific examples, R represents a hydrogen atom, an alkyl group which may have a substituent or a halogen atom, preferably a hydrogen atom, a methyl group, a hydroxymethyl group which is an alkyl group having a substituent, acetoxy Represents a methyl group.

  The repeating unit having a lactone structure is more preferably a repeating unit represented by the following general formula (3-1).

In general formula (3-1),
R ₇ , A, R ₀ , Z, and n are as defined in the general formula (3).
When there are a plurality of R _{9 s} , each independently represents an alkyl group which may have a substituent,
Which may have a substituent cycloalkyl group, substituents which may an ester group have, or cyano group, a hydroxyl group, an alkoxy group, in the presence of two or more bonded two R _9, A ring may be formed.
X represents an alkylene group, an oxygen atom, or a sulfur atom.
m is the number of substituents and represents an integer of 0 to 5. m is preferably 0 or 1.

The alkyl group for R ₉ is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and most preferably a methyl group. Examples of the cycloalkyl group include cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups. Examples of the ester group include a methoxycarbonyl group, an ethoxycarbonyl group, an n-butoxycarbonyl group, and a t-butoxycarbonyl group. Examples of the substituent include an alkoxy group such as a hydroxy group, a methoxy group, and an ethoxy group, and a halogen atom such as a cyano group and a fluorine atom. R ₉ is more preferably a cyano group.
R ₉ is more preferably a methyl group, a cyano group or an alkoxycarbonyl group, and even more preferably a cyano group.
Examples of the alkylene group for X include a methylene group and an ethylene group. X is preferably an oxygen atom or a methylene group, and more preferably a methylene group.
When m is 1 or more, at least one R ₉ is preferably substituted at the α-position or β-position of the lactone carbonyl group, particularly preferably at the α-position.

  Specific examples of the repeating unit having a group having a lactone structure represented by General Formula (3-1) are shown below, but the present invention is not limited thereto.

  The repeating unit having a lactone group usually has an optical isomer, but any optical isomer may be used. One optical isomer may be used alone, or a plurality of optical isomers may be mixed and used. When one kind of optical isomer is mainly used, the optical purity (ee) thereof is preferably 90 or more, more preferably 95 or more.

As for the content rate of the repeating unit which has a lactone group, 15-60 mol% is preferable with respect to all the repeating units in resin (A), More preferably, it is 20-50 mol%, More preferably, it is 30-50 mol%.
In order to enhance the effects of the present invention, two or more lactone repeating units selected from the general formula (3) can be used in combination. When using together, it is preferable to select and use 2 or more types from the lactone repeating unit in which n is 1 in general formula (3). Moreover, it is also preferable to use together the lactone repeating unit whose Ab is a single bond in General Formula (AII), and the lactone repeating unit whose n is 1 among General Formula (3).

The resin (A) preferably has a repeating unit having a hydroxyl group or a cyano group as a repeating unit other than the repeating units represented by the general formulas (2-1) and (3-1). This improves the substrate adhesion and developer compatibility. The repeating unit having a hydroxyl group or a cyano group is preferably a repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group, and preferably has no acid decomposability. The alicyclic hydrocarbon structure in the alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably an adamantyl group, a diamantyl group, or a norbornyl group. Preferred examples of the alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group include a monohydroxyadamantyl group, a dihydroxyadamantyl group, a monohydroxydiamantyl group, a dihydroxyadamantyl group, and a norbornyl group substituted with a cyano group.
As the alicyclic hydrocarbon structure substituted with a preferred hydroxyl group or cyano group, partial structures represented by the following general formulas (VIIa) to (VIId) are preferred.

In general formulas (VIIa) to (VIIc),
R ₂ c to R ₄ c each independently represents a hydrogen atom, a hydroxyl group or a cyano group. However, at least one of R ₂ c to R ₄ c represents a hydroxyl group or a cyano group. Preferably, one or two of R ₂ c to R ₄ c are a hydroxyl group and the remaining is a hydrogen atom. In general formula (VIIa), more preferably, _two of R ₂ c to R ₄ c are hydroxyl groups and the remaining are hydrogen atoms.

  Examples of the repeating unit having a partial structure represented by the general formulas (VIIa) to (VIId) include the repeating units represented by the following general formulas (AIIa) to (AIId).

In the general formulas (AIIa) to (AIId),
R ₁ c represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.
R ₂ c to R ₄ c are in the general formula (VIIa) ~ (VIIc), same meanings as R ₂ c~R ₄ c.

The content of the repeating unit having a hydroxyl group or a cyano group is preferably from 5 to 40 mol%, more preferably from 5 to 30 mol%, still more preferably from 10 to 25 mol%, based on all repeating units in the resin (A).

  Specific examples of the repeating unit having a hydroxyl group or a cyano group are given below, but the present invention is not limited thereto.

  The resin used in the photosensitive composition of the present invention may have a repeating unit having an alkali-soluble group. Examples of the alkali-soluble group include a carboxyl group, a sulfonamide group, a sulfonylimide group, a bisulsulfonylimide group, and an aliphatic alcohol (for example, hexafluoroisopropanol group) substituted with an electron withdrawing group at the α-position. It is more preferable to have a repeating unit. By containing the repeating unit having an alkali-soluble group, the resolution in contact hole applications is increased. The repeating unit having an alkali-soluble group includes a repeating unit in which an alkali-soluble group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid or methacrylic acid, or an alkali in the main chain of the resin through a linking group. Either a repeating unit to which a soluble group is bonded, or a polymerization initiator or chain transfer agent having an alkali-soluble group is introduced at the end of the polymer chain at the time of polymerization, both of which are preferable, and the linking group is monocyclic or polycyclic It may have a cyclic hydrocarbon structure. Particularly preferred are repeating units of acrylic acid or methacrylic acid.

  As for the content rate of the repeating unit which has an alkali-soluble group, 0-20 mol% is preferable with respect to all the repeating units in resin (A), More preferably, it is 3-15 mol%, More preferably, it is 5-10 mol%.

Specific examples of the repeating unit having an alkali-soluble group are shown below, but the present invention is not limited thereto. In specific examples, Rx represents H, CH ₃ , CH ₂ OH, or CF ₃ .

  The resin (A) of the present invention preferably further has a repeating unit that has an alicyclic hydrocarbon structure having no polar group and does not exhibit acid decomposability. This can reduce the elution of low molecular components from the resist film to the immersion liquid during immersion exposure. An example of such a repeating unit is a repeating unit represented by the general formula (4).

In general formula (4), R ₅ represents a hydrocarbon group having at least one cyclic structure and having neither a hydroxyl group nor a cyano group.
Ra represents a hydrogen atom, an alkyl group, or a —CH ₂ —O—Ra ₂ group. In the formula, Ra ₂ represents a hydrogen atom, an alkyl group or an acyl group. Ra is preferably a hydrogen atom, a methyl group, a hydroxymethyl group or a trifluoromethyl group, particularly preferably a hydrogen atom or a methyl group.

The cyclic structure possessed by R ₅ includes a monocyclic hydrocarbon group and a polycyclic hydrocarbon group. Examples of the monocyclic hydrocarbon group include cycloalkenyl having 3 to 12 carbon atoms such as cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group and the like, and cycloalkyl groups having 3 to 12 carbon atoms and cyclohexenyl group. Groups. Preferable monocyclic hydrocarbon groups are monocyclic hydrocarbon groups having 3 to 7 carbon atoms, and more preferable examples include a cyclopentyl group and a cyclohexyl group.

The polycyclic hydrocarbon group includes a ring assembly hydrocarbon group and a bridged cyclic hydrocarbon group, and examples of the ring assembly hydrocarbon group include a bicyclohexyl group and a perhydronaphthalenyl group. As the bridged cyclic hydrocarbon ring, for example, bicyclic such as pinane, bornane, norpinane, norbornane, bicyclooctane ring (bicyclo [2.2.2] octane ring, bicyclo [3.2.1] octane ring, etc.) Hydrocarbon rings and tricyclic hydrocarbon rings such as homobredan, adamantane, tricyclo [5.2.1.0 ^2,6 ] decane, tricyclo [4.3.1.1 ^2,5 ] undecane ring, tetracyclo [ 4.4.0.1 ^2,5 . 1 ^7,10 ] dodecane, and tetracyclic hydrocarbon rings such as perhydro-1,4-methano-5,8-methanonaphthalene ring. The bridged cyclic hydrocarbon ring includes a condensed cyclic hydrocarbon ring such as perhydronaphthalene (decalin), perhydroanthracene, perhydrophenanthrene, perhydroacenaphthene, perhydrofluorene, perhydroindene, perhydroindene. A condensed ring in which a plurality of 5- to 8-membered cycloalkane rings such as a phenalene ring are condensed is also included.

Preferred examples of the bridged cyclic hydrocarbon ring include a norbornyl group, an adamantyl group, a bicyclooctanyl group, a tricyclo [5,2,1,0 ^2,6 ] decanyl group, and the like. More preferable examples of the bridged cyclic hydrocarbon ring include a norbornyl group and an adamantyl group.

  These alicyclic hydrocarbon groups may have a substituent, and preferred substituents include a halogen atom, an alkyl group, a hydroxyl group protected with a protecting group, an amino group protected with a protecting group, and the like. It is done. Preferred halogen atoms include bromine, chlorine and fluorine atoms, and preferred alkyl groups include methyl, ethyl, butyl and t-butyl groups. The above alkyl group may further have a substituent, and the substituent which may further have a halogen atom, an alkyl group, a hydroxyl group protected with a protecting group, an amino protected with a protecting group The group can be mentioned.

  Examples of the protecting group include an alkyl group, a cycloalkyl group, an aralkyl group, a substituted methyl group, a substituted ethyl group, an alkoxycarbonyl group, and an aralkyloxycarbonyl group. Preferred alkyl groups include alkyl groups having 1 to 4 carbon atoms, preferred substituted methyl groups include methoxymethyl, methoxythiomethyl, benzyloxymethyl, t-butoxymethyl, 2-methoxyethoxymethyl groups, and preferred substituted ethyl groups. 1-ethoxyethyl, 1-methyl-1-methoxyethyl, preferred acyl groups include formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, pivaloyl groups, etc., aliphatic acyl groups having 1 to 6 carbon atoms, alkoxycarbonyl Examples of the group include an alkoxycarbonyl group having 1 to 4 carbon atoms.

The content of the repeating unit represented by the general formula (4) having neither a hydroxyl group nor a cyano group is preferably from 0 to 40 mol%, more preferably based on all repeating units in the resin (A). 0 to 20 mol%.
Specific examples of the repeating unit represented by the general formula (4) are listed below, but the present invention is not limited to these.
Specific examples of the repeating unit having an alicyclic hydrocarbon structure having no polar group and not exhibiting acid decomposability are shown below, but the present invention is not limited thereto. In the formula, Ra represents H, CH ₃ , CH ₂ OH, or CF ₃ .

  Resin (A) adjusts dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and resolution, heat resistance, sensitivity, etc., which are general required characteristics of resist, in addition to the above repeating structural units. For this purpose, various repeating structural units can be included.

  Resins used in the photosensitive composition of the present invention, in addition to the above repeating structural units, dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and further, resolving power which is a general necessary characteristic of resist, Various repeating structural units can be included for the purpose of adjusting heat resistance, sensitivity, and the like.

  Examples of such repeating structural units include, but are not limited to, repeating structural units corresponding to the following monomers.

As a result, the performance required for the resin, especially
(1) Solubility in coating solvent,
(2) Film formability (glass transition temperature),
(3) Alkali developability,
(4) Membrane slip (hydrophobic, alkali-soluble group selection),
(5) Adhesion of unexposed part to substrate,
(6) Dry etching resistance,
Etc. can be finely adjusted.

  As such a monomer, for example, a compound having one addition polymerizable unsaturated bond selected from acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, etc. Etc.

  In addition, any addition-polymerizable unsaturated compound that can be copolymerized with monomers corresponding to the above various repeating structural units may be copolymerized.

  In the resin (A), the molar ratio of each repeating structural unit is such as dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and general resist performance such as resolving power, heat resistance, sensitivity, etc. It is set appropriately to adjust.

When the composition of the present invention is for ArF exposure, the resin (A) used in the composition of the present invention preferably has no aromatic group from the viewpoint of transparency to ArF light. ) Preferably has a monocyclic or polycyclic alicyclic hydrocarbon structure.
In addition, it is preferable that resin (A) does not contain a fluorine atom and a silicon atom from a compatible viewpoint with the hydrophobic resin (HR) mentioned later.

  In the case of patterning by irradiation with ArF excimer laser light, the resin (A) is preferably one in which all of the repeating units are composed of (meth) acrylate-based repeating units. In this case, all of the repeating units are methacrylate repeating units, all of the repeating units are acrylate repeating units, or all of the repeating units are methacrylate repeating units and acrylate repeating units. Although it can be used, the acrylate-based repeating unit is preferably 50 mol% or less of the total repeating units. More preferably, the (meth) acrylate repeating unit having an acid-decomposable group represented by the general formula (AI) is 20 to 50 mol%, the (meth) acrylate repeating unit having a lactone group is 20 to 50 mol%, and a hydroxyl group. Alternatively, it is a copolymer containing 5 to 30 mol% of (meth) acrylate-based repeating units having an alicyclic hydrocarbon structure substituted with a cyano group, and further containing 0 to 20 mol% of other (meth) acrylate-based repeating units.

  In the case of patterning by irradiating the photosensitive composition of the present invention with KrF excimer laser light, electron beam, X-ray, high energy beam (EUV, etc.) having a wavelength of 50 nm or less, the resin (A) is represented by the general formula (AI). In addition to the repeating unit represented by the formula, it is preferable to further have a hydroxystyrene-based repeating unit. More preferably, it has a hydroxystyrene-based repeating unit, a hydroxystyrene-based repeating unit protected with an acid-decomposable group, and an acid-decomposable repeating unit such as a (meth) acrylic acid tertiary alkyl ester.

  Preferred repeating units having an acid-decomposable group include t-butoxycarbonyloxystyrene, 1-alkoxyethoxystyrene, (meth) acrylic acid tertiary alkyl ester repeating units, and the like. 2-alkyl-2 -Repeating units based on adamantyl (meth) acrylate and dialkyl (1-adamantyl) methyl (meth) acrylate are more preferred.

Resin (A) can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, a monomer polymerization method in which a monomer species and an initiator are dissolved in a solvent and heating is performed, and a solution of the monomer species and the initiator is dropped into the heating solvent over 1 to 10 hours. The dropping polymerization method is added, and the dropping polymerization method is preferable. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethylformamide and dimethylacetamide, Furthermore, the solvent which melt | dissolves the composition of this invention like the below-mentioned propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and cyclohexanone is mentioned. More preferably, the polymerization is performed using the same solvent as the solvent used in the photosensitive composition of the present invention. Thereby, generation | occurrence | production of the particle at the time of a preservation | save can be suppressed.
The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As a polymerization initiator, a commercially available radical initiator (azo initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is preferable. Preferred examples of the initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. If desired, an initiator is added or added in portions, and after completion of the reaction, it is put into a solvent and a desired polymer is recovered by a method such as powder or solid recovery. The concentration of the reaction is 5 to 50% by mass, preferably 10 to 30% by mass. The reaction temperature is usually from 10 ° C to 150 ° C, preferably from 30 ° C to 120 ° C, more preferably from 60 ° C to 100 ° C.

The weight average molecular weight of the resin (A) is preferably 1,000 to 200,000, more preferably 2,000 to 20,000, and even more preferably 3,000 to 15 in terms of polystyrene by GPC method. 1,000, particularly preferably 3,000 to 10,000. By setting the weight average molecular weight to 1,000 to 200,000, deterioration of heat resistance and dry etching resistance can be prevented, and developability is deteriorated, and viscosity is increased, resulting in deterioration of film forming property. Can be prevented.
The degree of dispersion (molecular weight distribution) is usually 1 to 3, preferably 1 to 2.6, more preferably 1 to 2, and particularly preferably 1.4 to 1.7. The smaller the molecular weight distribution, the better the resolution and pattern shape, the smoother the side wall of the pattern, and the better the roughness.

In the photosensitive composition of the present invention, the content of the resin (A) in the entire composition is preferably from 50 to 99.9% by mass, more preferably from 60 to 99.0% by mass, based on the total solid content.
In the present invention, the resin (A) may be used alone or in combination.

<3. Resin (resin (D)) that does not have a group that decomposes by the action of an acid>
The photosensitive composition of this invention may contain resin (resin (D)) which does not have the group decomposed | disassembled by the effect | action of an acid with resin (A). “No acid-decomposable group” means that the photosensitive composition of the present invention has no or very little decomposability due to the action of an acid in an image forming process in which the photosensitive composition of the present invention is usually used. It does not have a group that contributes to image formation. Examples of such a resin include a resin having an alkali-soluble group and a resin having a group that is decomposed by the action of an alkali and improves the solubility in an alkali developer.
The resin (D) is preferably a resin having at least one repeating unit derived from a (meth) acrylic acid derivative and / or an alicyclic olefin derivative.
Examples of the alkali-soluble group that can be contained in the resin (D) include a carboxyl group, a phenolic hydroxyl group, an aliphatic hydroxyl group substituted at the 1- or 2-position with an electron-withdrawing group, and amino substituted with an electron-withdrawing group. A group (for example, a sulfonamide group, a sulfonimide group, a bissulfonylimide group), a methylene group substituted with an electron withdrawing group or a methine group (for example, a methylene group substituted with at least two selected from a ketone group and an ester group) , A methine group).
The group that can be contained in the resin (D) and decomposes by the action of an alkali and increases the solubility in an alkali developer is preferably a lactone group or an acid anhydride group, and more preferably a lactone group. Specific examples of the repeating unit having a group that decomposes by the action of an alkali and increases the solubility in an alkali developer include the following repeating units.

The resin (D) may have a repeating unit having a functional group other than the above. As the repeating unit having another functional group, an appropriate functional group can be introduced in consideration of dry etching resistance, hydrophilicity / hydrophobicity, interaction property and the like.
Specifically, a repeating unit having a polar functional group such as a hydroxyl group, a cyano group, a carbonyl group, or an ester group, a repeating unit having a monocyclic or polycyclic hydrocarbon structure, a silicon atom, a halogen atom, or a fluoroalkyl group. Or a repeating unit having a plurality of these functional groups.

  Specific examples of preferred repeating units that can constitute the resin (D) are shown below.

The weight average molecular weight of the resin (D) is preferably from 500 to 50,000, more preferably from 800 to 10,000, particularly preferably from 1,000 to 8,000 as a polystyrene-converted value by the GPC method. By setting the weight average molecular weight to 500 to 50,000, a decrease in heat resistance and dry etching resistance can be further prevented, and developability is deteriorated, and viscosity is increased so that film-forming property is deteriorated. Can be prevented more.
The degree of dispersion (molecular weight distribution) is usually 1 to 3, preferably 1 to 2.6, more preferably 1 to 2, and particularly preferably 1.4 to 1.7. The smaller the molecular weight distribution, the better the resolution and pattern shape, the smoother the side wall of the pattern, and the better the roughness.
The suitable addition amount of resin (D) is 0-30 mass% with respect to resin (A), More preferably, it is 0-20 mass%, More preferably, it is 0-15 mass%.

<4. Solvent>
The photosensitive composition of the present invention may contain a solvent. The solvent may be any solvent that can be used for preparing the photosensitive composition by dissolving the above-described components, such as alkylene glycol monoalkyl ether carboxylate, alkylene glycol monoalkyl ether, alkyl lactate ester. , Alkyl alkoxypropionate, cyclic lactone (preferably having 4 to 10 carbon atoms), monoketone compound (preferably having 4 to 10 carbon atoms) which may contain a ring, alkylene carbonate, alkyl alkoxyacetate, alkyl pyruvate, etc. Mention may be made of solvents.

Examples of the alkylene glycol monoalkyl ether carboxylate include propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl Preferred examples include ether propionate, ethylene glycol monomethyl ether acetate, and ethylene glycol monoethyl ether acetate.
Preferred examples of the alkylene glycol monoalkyl ether include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether.

Preferred examples of the alkyl lactate include methyl lactate, ethyl lactate, propyl lactate and butyl lactate.
Preferable examples of the alkyl alkoxypropionate include ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, and ethyl 3-methoxypropionate.

  Examples of the cyclic lactone include β-propiolactone, β-butyrolactone, γ-butyrolactone, α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone, γ-caprolactone, and γ-octano. Preferred are iclactone and α-hydroxy-γ-butyrolactone.

  Examples of the monoketone compound which may contain a ring include 2-butanone, 3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone, 3-methyl-2-pentanone, 4-methyl-2-pentanone, 2 -Methyl-3-pentanone, 4,4-dimethyl-2-pentanone, 2,4-dimethyl-3-pentanone, 2,2,4,4-tetramethyl-3-pentanone, 2-hexanone, 3-hexanone, 5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-methyl-3-heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4-heptanone, 2-octanone, 3-octanone, 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone, 3-decanone, 4-decanone, 5-hexen-2-one, -Penten-2-one, cyclopentanone, 2-methylcyclopentanone, 3-methylcyclopentanone, 2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone, cyclohexanone, 3-methyl Cyclohexanone, 4-methylcyclohexanone, 4-ethylcyclohexanone, 2,2-dimethylcyclohexanone, 2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone, 2-methylcycloheptanone, 3-methylcyclo A preferred example is heptanone.

Preferred examples of the alkylene carbonate include propylene carbonate, vinylene carbonate, ethylene carbonate, and butylene carbonate.
Examples of the alkyl alkoxyacetate include 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 2- (2-ethoxyethoxy) ethyl acetate, 3-methoxy-3-methylbutyl acetate, and 1-methoxy-acetate. 2-propyl is preferred.
Preferred examples of the alkyl pyruvate include methyl pyruvate, ethyl pyruvate, and propyl pyruvate.
As a solvent which can be preferably used, a solvent having a boiling point of 130 ° C. or higher under normal temperature and normal pressure can be mentioned. Specifically, cyclopentanone, γ-butyrolactone, cyclohexanone, ethyl lactate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, ethyl 3-ethoxypropionate, ethyl pyruvate, acetic acid-2
-Ethoxyethyl, 2- (2-ethoxyethoxy) ethyl acetate, propylene carbonate are mentioned.
In the present invention, the above solvents may be used alone or in combination of two or more.

In this invention, you may use the mixed solvent which mixed the solvent which contains a hydroxyl group in a structure, and the solvent which does not contain a hydroxyl group as an organic solvent.
Examples of the solvent containing a hydroxyl group include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethyl lactate, and the like. Particularly preferred are propylene glycol monomethyl ether and ethyl lactate.
Examples of the solvent not containing a hydroxyl group include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, butyl acetate, N-methylpyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide and the like. Among these, propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, and butyl acetate are particularly preferred, and propylene glycol monomethyl ether acetate, ethyl ethoxypropionate. 2-heptanone is most preferred.

  The mixing ratio (mass) of the solvent containing a hydroxyl group and the solvent not containing a hydroxyl group is 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 60/40. . A mixed solvent containing 50% by mass or more of a solvent not containing a hydroxyl group is particularly preferred from the viewpoint of coating uniformity.

  The solvent is preferably a mixed solvent of two or more containing propylene glycol monomethyl ether acetate.

<5. Acid diffusibility inhibitor>
The photosensitive composition of the present invention further contains two or more acid diffusibility inhibitors that can control the diffusibility of the acid generated from the acid generator in order to reduce the change in performance over time from exposure to heating. obtain.
The ability to suppress acid diffusibility can be determined by using as an index that the optimum exposure amount has decreased in sensitivity when a pattern is formed after exposure processing and development.
Moreover, "pattern collapse" which is one of litho performance can be suppressed by containing two or more types of acid diffusion inhibitors. Although the details of the reason are unknown, it is an effect of being able to control the diffusion of the generated acid stepwise and in multiple stages by using many different types of acid diffusion inhibitors in combination. Estimated.
For example, a combination of acid diffusion inhibitors having different molecular weights is preferable. As a guide, a molecular weight of 350 or more is classified as large, and the following molecular weight is classified as small. Moreover, the combination of the acid diffusibility inhibitor from which basic intensity | strength differs is preferable. As a guide, the basicity higher than pKa5 is classified as large, and the basicity below is classified as small.
With respect to the acid diffusion inhibitor having the largest addition amount, the further acid diffusion inhibitor is preferably used in an amount of preferably 5 to 40% by mass, more preferably 10 to 40% by mass and 15 to 40% by mass. it can.
Examples of the acid diffusibility inhibitor include basic compounds and carboxylic acid onium salts.

<5a. Basic compounds>
Preferred examples of the basic compound include compounds having structures represented by the following formulas (A) to (E).

In general formulas (A) and (E),
R ²⁰⁰ , R ²⁰¹ and R ²⁰² may be the same or different, and are a hydrogen atom, an alkyl group (preferably having 1 to 20 carbon atoms), a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (having a carbon number). 6-20), wherein R ²⁰¹ and R ²⁰² may combine with each other to form a ring.
R ²⁰³ , R ²⁰⁴ , R ²⁰⁵ and R ²⁰⁶ may be the same or different and each represents an alkyl group having 1 to 20 carbon atoms.
About the said alkyl group, as an alkyl group which has a substituent, a C1-C20 aminoalkyl group, a C1-C20 hydroxyalkyl group, or a C1-C20 cyanoalkyl group is preferable.
The alkyl groups in the general formulas (A) and (E) are more preferably unsubstituted.

  Preferred compounds include guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, piperidine and the like, and more preferred compounds include imidazole structure, diazabicyclo structure, onium hydroxide structure, onium carboxylate Examples thereof include a compound having a structure, a trialkylamine structure, an aniline structure or a pyridine structure, an alkylamine derivative having a hydroxyl group and / or an ether bond, and an aniline derivative having a hydroxyl group and / or an ether bond.

  Examples of the compound having an imidazole structure include imidazole, 2,4,5-triphenylimidazole, benzimidazole, and 2-phenylbenzimidazole. Examples of the compound having a diazabicyclo structure include 1,4-diazabicyclo [2,2,2] octane, 1,5-diazabicyclo [4,3,0] non-5-ene, and 1,8-diazabicyclo [5,4,0. ] Undecar 7-ene etc. are mentioned. Examples of the compound having an onium hydroxide structure include tetrabutylammonium hydroxide, triarylsulfonium hydroxide, phenacylsulfonium hydroxide, sulfonium hydroxide having a 2-oxoalkyl group, specifically, triphenylsulfonium hydroxide, tris ( and t-butylphenyl) sulfonium hydroxide, bis (t-butylphenyl) iodonium hydroxide, phenacylthiophenium hydroxide, 2-oxopropylthiophenium hydroxide, and the like. As the compound having an onium carboxylate structure, an anion portion of the compound having an onium hydroxide structure is converted to a carboxylate, and examples thereof include acetate, adamantane-1-carboxylate, and perfluoroalkylcarboxylate. Examples of the compound having a trialkylamine structure include tri (n-butyl) amine and tri (n-octyl) amine. Examples of the aniline compound include 2,6-diisopropylaniline, N, N-dimethylaniline, N, N-dibutylaniline, N, N-dihexylaniline and the like. Examples of the alkylamine derivative having a hydroxyl group and / or an ether bond include ethanolamine, diethanolamine, triethanolamine, N-phenyldiethanolamine, and tris (methoxyethoxyethyl) amine. Examples of aniline derivatives having a hydroxyl group and / or an ether bond include N, N-bis (hydroxyethyl) aniline.

Preferred examples of the basic compound further include an amine compound having a phenoxy group, an ammonium salt compound having a phenoxy group, an amine compound having a sulfonic acid ester group, and an ammonium salt compound having a sulfonic acid ester group.
As the amine compound, a primary, secondary or tertiary amine compound can be used, and an amine compound in which at least one alkyl group is bonded to a nitrogen atom is preferable. The amine compound is more preferably a tertiary amine compound. As long as at least one alkyl group (preferably having 1 to 20 carbon atoms) is bonded to a nitrogen atom, the amine compound has an cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (preferably having 3 to 20 carbon atoms). Preferably C6-C12) may be bonded to a nitrogen atom. The amine compound preferably has an oxygen atom in the alkyl chain and an oxyalkylene group is formed. The number of oxyalkylene groups is 1 or more, preferably 3 to 9, more preferably 4 to 6 in the molecule. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.

As the ammonium salt compound, a primary, secondary, tertiary, or quaternary ammonium salt compound can be used, and an ammonium salt compound in which at least one alkyl group is bonded to a nitrogen atom is preferable. As long as at least one alkyl group (preferably having 1 to 20 carbon atoms) is bonded to a nitrogen atom, the ammonium salt compound has a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group in addition to the alkyl group. (Preferably having 6 to 12 carbon atoms) may be bonded to a nitrogen atom. The ammonium salt compound preferably has an oxygen atom in the alkyl chain and an oxyalkylene group is formed. The number of oxyalkylene groups is 1 or more, preferably 3 to 9, more preferably 4 to 6 in the molecule. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.
Examples of the anion of the ammonium salt compound include halogen atoms, sulfonates, borates, and phosphates. Among them, halogen atoms and sulfonates are preferable. As the halogen atom, chloride, bromide, and iodide are particularly preferable. As the sulfonate, an organic sulfonate having 1 to 20 carbon atoms is particularly preferable. Examples of the organic sulfonate include alkyl sulfonates having 1 to 20 carbon atoms and aryl sulfonates. The alkyl group of the alkyl sulfonate may have a substituent, and examples of the substituent include fluorine, chlorine, bromine, alkoxy groups, acyl groups, and aryl groups. Specific examples of the alkyl sulfonate include methane sulfonate, ethane sulfonate, butane sulfonate, hexane sulfonate, octane sulfonate, benzyl sulfonate, trifluoromethane sulfonate, pentafluoroethane sulfonate, and nonafluorobutane sulfonate. Examples of the aryl group of the aryl sulfonate include a benzene ring, a naphthalene ring, and an anthracene ring. The benzene ring, naphthalene ring and anthracene ring may have a substituent, and the substituent is preferably a linear or branched alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms. Specific examples of the linear or branched alkyl group and cycloalkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, i-butyl, t-butyl, n-hexyl, cyclohexyl and the like. Examples of the other substituent include an alkoxy group having 1 to 6 carbon atoms, a halogen atom, cyano, nitro, an acyl group, and an acyloxy group.

The amine compound having a phenoxy group and the ammonium salt compound having a phenoxy group are those having a phenoxy group at the terminal opposite to the nitrogen atom of the alkyl group of the amine compound or ammonium salt compound. The phenoxy group may have a substituent. Examples of the substituent of the phenoxy group include an alkyl group, an alkoxy group, a halogen atom, a cyano group, a nitro group, a carboxyl group, a carboxylic acid ester group, a sulfonic acid ester group, an aryl group, an aralkyl group, an acyloxy group, and an aryloxy group. Etc. The substitution position of the substituent may be any of the 2-6 positions. The number of substituents may be any in the range of 1 to 5.
It is preferable to have at least one oxyalkylene group between the phenoxy group and the nitrogen atom. The number of oxyalkylene groups is 1 or more, preferably 3 to 9, more preferably 4 to 6 in the molecule. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.

In the amine compound having a sulfonic acid ester group and the ammonium salt compound having a sulfonic acid ester group, the sulfonic acid ester group may be any of alkyl sulfonic acid ester, cycloalkyl group sulfonic acid ester, and aryl sulfonic acid ester. In the case of an alkyl sulfonate ester, the alkyl group has 1 to 20 carbon atoms. In the case of a cycloalkyl sulfonate ester, the cycloalkyl group has 3 to 20 carbon atoms. In the case of an aryl sulfonate ester, the aryl group has 6 carbon atoms. ~ 12 are preferred. Alkyl sulfonic acid ester, cycloalkyl sulfonic acid ester, and aryl sulfonic acid ester may have a substituent. Examples of the substituent include a halogen atom, a cyano group, a nitro group, a carboxyl group, a carboxylic acid ester group, and a sulfonic acid. An ester group is preferred.
It is preferable to have at least one oxyalkylene group between the sulfonate group and the nitrogen atom. The number of oxyalkylene groups is 1 or more, preferably 3 to 9, more preferably 4 to 6 in the molecule. Among the oxyalkylene groups, an oxyethylene group (—CH ₂ CH ₂ O—) or an oxypropylene group (—CH (CH ₃ ) CH ₂ O— or —CH ₂ CH ₂ CH ₂ O—) is preferable, and more preferably oxy Ethylene group.

  These basic compounds are used alone or in combination of two or more.

  The usage-amount of a basic compound is 0.001-10 mass% normally on the basis of solid content of a photosensitive composition, Preferably it is 0.01-5 mass%.

  The use ratio of the acid generator and the basic compound in the composition is preferably acid generator / basic compound (molar ratio) = 1.0 to 300. That is, the molar ratio is preferably 1.0 or more from the viewpoints of sensitivity and resolution, and is preferably 300 or less from the viewpoint of suppressing the reduction in resolution due to the thickening of the resist pattern over time until post-exposure heat treatment. The acid generator / basic compound (molar ratio) is more preferably 1.5 to 200, still more preferably 2.0 to 150.

<5b. Carboxylic acid onium salt>
Examples of the carboxylic acid onium salt include a carboxylic acid sulfonium salt, a carboxylic acid iodonium salt, and a carboxylic acid ammonium salt. In particular, as the carboxylic acid onium salt, an iodonium salt and a sulfonium salt are preferable. Furthermore, it is preferable that the carboxylate residue of the carboxylic acid onium salt of the present invention does not contain an aromatic group or a carbon-carbon double bond. As a particularly preferable anion moiety, a linear, branched, monocyclic or polycyclic alkylcarboxylic acid anion having 1 to 30 carbon atoms is preferable. More preferably, an anion of a carboxylic acid in which some or all of these alkyl groups are fluorine-substituted is preferable. The alkyl chain may contain an oxygen atom. This ensures transparency with respect to light of 220 nm or less, improves sensitivity and resolution, and improves density dependency and exposure margin.

Fluoro-substituted carboxylic acid anions include fluoroacetic acid, difluoroacetic acid, trifluoroacetic acid, pentafluoropropionic acid, heptafluorobutyric acid, nonafluoropentanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, perfluorocyclohexanecarboxylic acid, 2 , 2-bistrifluoromethylpropionic acid anion and the like.

  These carboxylic acid onium salts can be synthesized by reacting sulfonium hydroxide, iodonium hydroxide, ammonium hydroxide and carboxylic acid with silver oxide in a suitable solvent.

  The content of the carboxylic acid onium salt in the composition is generally 0.1 to 20% by mass, preferably 0.5 to 10% by mass, more preferably 1 to 7% by mass, based on the total solid content of the composition. %.

<6. Surfactant>
A surfactant may be added to the photosensitive composition of the present invention, and in the case of adding a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant, silicon-based surfactant, fluorine atom) Or a surfactant having both silicon atoms and two or more thereof.

When the photosensitive composition of the present invention contains the above-mentioned surfactant, it provides a resist pattern with less sensitivity and development defects with good sensitivity and resolution when using an exposure light source of 250 nm or less, particularly 220 nm or less. Is possible.
Examples of the fluorine-based and / or silicon-based surfactant include, for example, JP-A No. 62-36663, JP-A No. 61-226746, JP-A No. 61-226745, JP-A No. 62-170950, JP 63-34540 A, JP 7-230165 A, JP 8-62834 A, JP 9-54432 A, JP 9-5988 A, JP 2002-277862 A, US Patent Nos. 5,405,720, 5,360,692, 5,529,881, 5,296,330, 5,436,098, 5,576,143, 5,294,511, 5,824,451 Surfactant can be mentioned, The following commercially available surfactant can also be used as it is.

  Examples of commercially available surfactants that can be used include F-top EF301, EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431, 4430 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176, F189 , F113, F110, F177, F120, R08 (Dainippon Ink Chemical Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troisol S-366 (Manufactured by Troy Chemical Co., Ltd.), GF-300, GF-150 (manufactured by Toagosei Chemical Co., Ltd.), Surflon S-393 (manufactured by Seimi Chemical Co., Ltd.), F-top EF121, EF122A, EF122B, RF122C, EF125M , EF135M, EF351, 352, EF801, EF802, EF 01 (manufactured by Gemco), PF636, PF656, PF6320, PF6520 (manufactured by OMNOVA), FTX-204G, 208G, 218G, 230G, 204D, 208D, 212D, 218D, 222D (manufactured by Neos) Fluorine type surfactant or silicon type surfactant can be mentioned. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon-based surfactant.

In addition to the known surfactants described above, surfactants are derived from fluoroaliphatic compounds produced by the telomerization method (also referred to as the telomer method) or the oligomerization method (also referred to as the oligomer method). A surfactant using a polymer having a fluoroaliphatic group can be used. The fluoroaliphatic compound can be synthesized by the method described in JP-A-2002-90991.
As the polymer having a fluoroaliphatic group, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate and / or (poly (oxyalkylene)) methacrylate is preferable and distributed irregularly. Or may be block copolymerized. Examples of the poly (oxyalkylene) group include a poly (oxyethylene) group, a poly (oxypropylene) group, a poly (oxybutylene) group, and the like, and a poly (oxyethylene, oxypropylene, and oxyethylene group). A unit having different chain lengths in the same chain length, such as a block link) or poly (block link of oxyethylene and oxypropylene) may be used. Furthermore, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate (or methacrylate) is not only a binary copolymer but also a monomer having two or more different fluoroaliphatic groups, Further, it may be a ternary or higher copolymer obtained by simultaneously copolymerizing two or more different (poly (oxyalkylene)) acrylates (or methacrylates).

Examples of commercially available surfactants include Megafac F178, F-470, F-473, F-475, F-476, and F-472 (Dainippon Ink Chemical Co., Ltd.). Further, a copolymer of an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxyalkylene)) acrylate (or methacrylate), an acrylate (or methacrylate) having a C ₃ F ₇ group and (poly (oxy And a copolymer of (ethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate).

  In the present invention, other surfactants other than fluorine-based and / or silicon-based surfactants can also be used. Specifically, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether, etc. Sorbitans such as polyoxyethylene alkyl aryl ethers, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate Fatty acid esters, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopa Mite - DOO, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, may be mentioned polyoxyethylene sorbitan tristearate nonionic surfactants of polyoxyethylene sorbitan fatty acid esters such as such.

  These surfactants may be used alone or in several combinations.

  When adding surfactant, it is 0.0001-2 mass% with respect to the photosensitive composition whole quantity (except a solvent), More preferably, it is 0.001-1 mass%.

<7. Dissolution inhibitor compound>
The photosensitive composition of the present invention may contain a dissolution inhibiting compound having a molecular weight of 3000 or less (hereinafter also referred to as “dissolution inhibiting compound”) that decomposes by the action of an acid and increases the solubility in an alkaline developer. Good.
The dissolution inhibiting compound contains an acid-decomposable group, such as a cholic acid derivative containing an acid-decomposable group described in Proceeding of SPIE, 2724,355 (1996), in order not to lower the permeability of 220 nm or less. Preferred are alicyclic or aliphatic compounds. Examples of the acid-decomposable group and the alicyclic structure are the same as those described for the resin (A).

When exposing the photosensitive composition of this invention with a KrF excimer laser, or irradiating with an electron beam, what contains the structure which substituted the phenolic hydroxyl group of the phenol compound by the acid-decomposable group is preferable. The phenol compound preferably contains 1 to 9 phenol skeletons, more preferably 2 to 6 phenol skeletons.

  The molecular weight of the dissolution inhibiting compound in the present invention is 3000 or less, preferably 300 to 3000, and more preferably 500 to 2500.

  The addition amount of the dissolution inhibiting compound is preferably 3 to 50% by mass, more preferably 5 to 40% by mass, based on the solid content of the photosensitive composition.

  Specific examples of the dissolution inhibiting compound are shown below, but the present invention is not limited thereto.

<8. Other additives>
In the photosensitive composition of the present invention, if necessary, a dye, a plasticizer, a photosensitizer, a light absorber, and a compound that promotes solubility in a developer (for example, a phenol compound having a molecular weight of 1000 or less, a carboxyl An alicyclic or aliphatic compound having a group) or the like.

Such a phenol compound having a molecular weight of 1000 or less is described in, for example, JP-A-4-1222938, JP-A-2-28531, US Pat. No. 4,916,210, European Patent 219294, and the like. It can be easily synthesized by those skilled in the art with reference to the method.
Specific examples of alicyclic or aliphatic compounds having a carboxyl group include carboxylic acid derivatives having a steroid structure such as cholic acid, deoxycholic acid, lithocholic acid, adamantane carboxylic acid derivatives, adamantane dicarboxylic acid, cyclohexane carboxylic acid, cyclohexane Examples thereof include, but are not limited to, dicarboxylic acids.

<9. Hydrophobic resin (HR)>
When exposing the photosensitive film | membrane which consists of a photosensitive composition of this invention through an immersion medium, hydrophobic resin (HR) can be further added as needed. As a result, the hydrophobic resin (HR) is unevenly distributed on the surface of the photosensitive film, and when the immersion medium is water, the receding contact angle of the photosensitive film surface with respect to the water when the photosensitive film is formed is improved, and the immersion water is followed. Can be improved. As the hydrophobic resin (HR), any resin can be used as long as the receding contact angle of the surface can be improved by addition, but a resin having at least one of fluorine atom and silicon atom is preferable. The receding contact angle of the photosensitive film is preferably 60 ° to 90 °, more preferably 70 ° or more. The addition amount can be adjusted as appropriate so that the receding contact angle of the photosensitive film falls within the above range, but is preferably 0.1 to 10% by mass based on the total solid content of the photosensitive composition, More preferably, it is 0.1-5 mass%. Hydrophobic resin (HR) is ubiquitous at the interface as described above, but unlike a surfactant, it does not necessarily have a hydrophilic group in the molecule, and polar / nonpolar substances are mixed uniformly. There is no need to contribute.
The receding contact angle is the contact angle measured when the contact line at the droplet-substrate interface recedes,
It is generally known to be useful in simulating the ease with which a droplet moves in a dynamic state. In simple terms, it can be defined as the contact angle when the droplet interface recedes when the droplet discharged from the needle tip is deposited on the substrate and then sucked into the needle again. It can be measured by using a contact angle measuring method generally called an expansion / contraction method.
In the immersion exposure process, the immersion head needs to move on the wafer following the movement of the exposure head to scan the wafer at high speed to form the exposure pattern. In this case, the contact angle of the immersion liquid with respect to the photosensitive film becomes important, and the photosensitive composition as a resist is required to follow the high-speed scanning of the exposure head without remaining droplets.

  The fluorine atom or silicon atom in the hydrophobic resin (HR) may be contained in the main chain of the resin or may be substituted on the side chain.

The hydrophobic resin (HR) is preferably a resin having an alkyl group having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom as a partial structure having a fluorine atom.
The alkyl group having a fluorine atom (preferably having 1 to 10 carbon atoms, more preferably 1 to 4 carbon atoms) is a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, It may have a substituent.
The cycloalkyl group having a fluorine atom is a monocyclic or polycyclic cycloalkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and may further have another substituent. Examples of the aryl group having a fluorine atom include those in which at least one hydrogen atom of an aryl group such as a phenyl group or a naphthyl group is substituted with a fluorine atom, and the aryl group may further have another substituent.

  Preferred examples of the alkyl group having a fluorine atom, the cycloalkyl group having a fluorine atom, or the aryl group having a fluorine atom include groups represented by the following general formulas (F2) to (F4). The present invention is not limited to this.

In general formulas (F2) to (F4),
R _{57 to} R ₆₈ each independently represents a hydrogen atom, a fluorine atom or an alkyl group. However, at least one of R _{57 to} R ₆₁ , R _{62 to} R ₆₄ and R _{65 to} R ₆₈ is a fluorine atom or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom (preferably having a carbon number of 1 ~ 4). R _{57 to} R ₆₁ and R _{65 to} R ₆₇ are preferably all fluorine atoms. R ₆₂ , R ₆₃ and R ₆₈ are preferably an alkyl group (preferably having 1 to 4 carbon atoms) in which at least one hydrogen atom is substituted with a fluorine atom, and preferably a perfluoroalkyl group having 1 to 4 carbon atoms. Further preferred. R ₆₂ and R ₆₃ may be connected to each other to form a ring.

Specific examples of the group represented by the general formula (F2) include a p-fluorophenyl group, a pentafluorophenyl group, and a 3,5-di (trifluoromethyl) phenyl group.
Specific examples of the group represented by the general formula (F3) include trifluoromethyl group, pentafluoropropyl group, pentafluoroethyl group, heptafluorobutyl group, hexafluoroisopropyl group, heptafluoroisopropyl group, hexafluoro (2 -Methyl) isopropyl group, nonafluorobutyl group, octafluoroisobutyl group, nonafluorohexyl group, nonafluoro-t-butyl group, perfluoroisopentyl group, perfluorooctyl group, perfluoro (trimethyl) hexyl group, 2,2 1,3,3-tetrafluorocyclobutyl group, perfluorocyclohexyl group and the like. Hexafluoroisopropyl group, heptafluoroisopropyl group, hexafluoro (2-methyl) isopropyl group, octafluoroisobutyl group, nonafluoro-t-butyl group and perfluoroisopentyl group are preferable, and hexafluoroisopropyl group and heptafluoroisopropyl group are preferable. Further preferred.
Specific examples of the group represented by the general formula (F4) include, for example, —C (CF ₃ ) ₂ OH, —C (C ₂ F ₅ ) ₂ OH, —C (CF ₃ ) (CH ₃ ) OH, -CH (CF ₃₎ OH and the like, -C (CF _{3) 2} OH is preferred.

Hereinafter, although the specific example of the repeating unit which has a fluorine atom is shown, this invention is not limited to this.
In specific examples, X ₁ represents a hydrogen atom, —CH ₃ , —F or —CF ₃ .
X ₂ represents —F or —CF ₃ .

The hydrophobic resin (HR) may contain a silicon atom. The partial structure having a silicon atom is preferably a resin having an alkylsilyl structure (preferably a trialkylsilyl group) or a cyclic siloxane structure.
Specific examples of the alkylsilyl structure or the cyclic siloxane structure include groups represented by the following general formulas (CS-1) to (CS-3).

In general formulas (CS-1) to (CS-3),
R _{12 to} R ₂₆ each independently represents a linear or branched alkyl group (preferably having 1 to 20 carbon atoms) or a cycloalkyl group (preferably having 3 to 20 carbon atoms).
L < ₃ > -L < ₅ > represents a single bond or a bivalent coupling group. Examples of the divalent linking group include an alkylene group, a phenylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, a urethane group, or a urea group, or a single group of two or more groups. A combination is mentioned.
n represents an integer of 1 to 5.

Hereinafter, although the specific example of the repeating unit which has group represented by general formula (CS-1)-(CS-3) is given, this invention is not limited to this. In specific examples, X ₁ represents a hydrogen atom, —CH ₃ , —F or —CF ₃ .

Furthermore, the hydrophobic resin (HR) may have at least one group selected from the following groups (x) to (z).
(X) an alkali-soluble group,
(Y) a group that decomposes by the action of an alkali developer and increases the solubility in the alkali developer;
(Z) A group that decomposes by the action of an acid.

(X) Alkali-soluble groups include phenolic hydroxyl groups, carboxylic acid groups, fluorinated alcohol groups, sulfonic acid groups, sulfonamido groups, sulfonylimide groups, (alkylsulfonyl) (alkylcarbonyl) methylene groups, (alkylsulfonyl) ( Alkylcarbonyl) imide group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene group, tris (alkylsulfonyl) ) And a methylene group.
Preferred alkali-soluble groups include fluorinated alcohol groups (preferably hexafluoroisopropanol), sulfonimide groups, and bis (carbonyl) methylene groups.

Examples of the repeating unit having an alkali-soluble group (x) include a repeating unit in which an alkali-soluble group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid or methacrylic acid, or a main group of the resin via a linking group. Examples include repeating units in which an alkali-soluble group is bonded to the chain. Furthermore, a polymerization initiator or a chain transfer agent having an alkali-soluble group can be used at the time of polymerization to be introduced at the end of the polymer chain. Is also preferable.
The content of the repeating unit having an alkali-soluble group (x) is preferably from 1 to 50 mol%, more preferably from 3 to 35 mol%, still more preferably from 5 to 20 mol%, based on all repeating units in the polymer.

  Specific examples of the repeating unit having an alkali-soluble group (x) are shown below, but the present invention is not limited thereto.

(Y) Examples of the group that decomposes by the action of an alkali developer and increases the solubility in the alkali developer include a group having a lactone structure, an acid anhydride group, an acid imide group, and the like, and preferably a lactone A group having a structure.
Group (y) which decomposes by the action of an alkali developer and increases the solubility in the alkali developer
As the repeating unit having a group (y), which is decomposed by the action of an alkali developer on the main chain of the resin and increases the solubility in the alkali developer, such as a repeating unit of an acrylic ester or a methacrylic ester. It is preferable to use a polymerization initiator or a chain transfer agent having a repeating unit that is bonded or a group (y) that increases the solubility in an alkaline developer at the end of the polymer chain during polymerization.
The content of the repeating unit having a group (y) whose solubility in an alkali developer is increased is preferably 1 to 40 mol%, more preferably 3 to 30 mol%, still more preferably based on all repeating units in the polymer. 5 to 15 mol%.

  Specific examples of the repeating unit having a group (y) that increases the solubility in an alkali developer include the same repeating units as those having a lactone structure exemplified in the resin (A).

  In the hydrophobic resin (HR), examples of the repeating unit having a group (z) that is decomposed by the action of an acid are the same as the repeating unit having an acid-decomposable group listed for the resin (A). In the hydrophobic resin (HR), the content of the repeating unit having a group (z) that is decomposed by the action of an acid is preferably 1 to 80 mol%, more preferably 10 to 10%, based on all repeating units in the polymer. 80 mol%, more preferably 20 to 60 mol%.

  The hydrophobic resin (HR) may further have a repeating unit represented by the following general formula (III).

In general formula (III):
R _{c 31} represents a hydrogen atom, an alkyl group, or an alkyl group which may be substituted by fluorine, a cyano group or -CH ₂ -O-Rac ₂ group. Wherein, Rac ₂ represents a hydrogen atom, an alkyl group or an acyl group. R _c31 is preferably a hydrogen atom, a methyl group, a hydroxymethyl group or a trifluoromethyl group, particularly preferably a hydrogen atom or a methyl group.
R _c32 represents a group having an alkyl group, a cycloalkyl group, an alkenyl group, or a cycloalkenyl group. These groups may be substituted with a fluorine atom or a silicon atom.
L _c3 represents a single bond or a divalent linking group.
In general formula (III), the alkyl group represented by R _c32 is preferably a linear or branched alkyl group having 3 to 20 carbon atoms.
The cycloalkyl group is preferably a cycloalkyl group having 3 to 20 carbon atoms.
The alkenyl group is preferably an alkenyl group having 3 to 20 carbon atoms.
The cycloalkenyl group is preferably a cycloalkenyl group having 3 to 20 carbon atoms.
R _c32 is preferably an unsubstituted alkyl group or an alkyl group substituted with a fluorine atom.
The divalent linking group of L _c3 is preferably an ester group, an alkylene group (preferably having a carbon number of 1 to 5), an oxy group, a phenylene group, or an ester bond (a group represented by —COO—).

  The hydrophobic resin (HR) is also preferably a repeating unit represented by the following general formula (CII-AB).

In the formula (CII-AB),
R ₁₁ ′ and R ₁₂ ′ each independently represents a hydrogen atom, a cyano group, a halogen atom or an alkyl group.
Zc ′ represents an atomic group for forming an alicyclic structure containing two bonded carbon atoms (C—C).
Specific examples of the repeating unit represented by the general formulas (III) and (CII-AB) are shown below, but the present invention is not limited thereto. In the formula, Ra represents H, CH ₃ , CH ₂ OH, CF ₃ or CN.

When the hydrophobic resin (HR) has a fluorine atom, the fluorine atom content is preferably 5 to 80% by mass, and 10 to 80% by mass with respect to the molecular weight of the hydrophobic resin (HR). Is more preferable. Moreover, it is preferable that the repeating unit containing a fluorine atom is 10-100 mass% in hydrophobic resin (HR), and it is more preferable that it is 30-100 mass%.
When the hydrophobic resin (HR) has a silicon atom, the content of the silicon atom is determined by the hydrophobic resin (HR).
) Is preferably 2 to 50% by mass, more preferably 2 to 30% by mass. Moreover, it is preferable that it is 10-100 mass% in hydrophobic resin (HR), and, as for the repeating unit containing a silicon atom, it is more preferable that it is 20-100 mass%.

  The weight average molecular weight of the hydrophobic resin (HR) in terms of standard polystyrene is preferably 1,000 to 100,000, more preferably 1,000 to 50,000, and even more preferably 2,000 to 15,000. is there.

  As in the case of the resin (A), the hydrophobic resin (HR) preferably has 0 to 10% by mass of residual monomer and oligomer components, and more preferably has few impurities such as metals. 0-5 mass% and 0-1 mass% are still more preferable. Thereby, a resist having no change over time such as foreign matter in liquid or sensitivity can be obtained. The molecular weight distribution (Mw / Mn, also referred to as dispersity) is preferably in the range of 1 to 5, more preferably 1 to 3, and still more preferably from the viewpoints of resolution, resist shape, resist pattern sidewall, roughness, and the like. It is the range of 1-2.

  As the hydrophobic resin (HR), various commercially available products can be used, or they can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, a monomer polymerization method in which a monomer species and an initiator are dissolved in a solvent and heating is performed, and a solution of the monomer species and the initiator is dropped into the heating solvent over 1 to 10 hours. The dropping polymerization method is added, and the dropping polymerization method is preferable. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethylformamide and dimethylacetamide, Furthermore, the solvent which melt | dissolves the composition of this invention like the below-mentioned propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and cyclohexanone is mentioned. More preferably, the polymerization is performed using the same solvent as the solvent used for preparing the photosensitive composition. Thereby, generation | occurrence | production of the particle at the time of a preservation | save can be suppressed.

  The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As a polymerization initiator, a commercially available radical initiator (azo initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is preferable. Preferred examples of the initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. The concentration of the reaction is 5 to 50% by mass, preferably 30 to 50% by mass. The reaction temperature is usually from 10 ° C to 150 ° C, preferably from 30 ° C to 120 ° C, more preferably from 60 ° C to 100 ° C.

  After completion of the reaction, the mixture is allowed to cool to room temperature and purified. Purification can be accomplished by a liquid-liquid extraction method that removes residual monomers and oligomer components by combining water and an appropriate solvent, and a purification method in a solution state such as ultrafiltration that extracts and removes only those having a specific molecular weight or less. , Reprecipitation method that removes residual monomer by coagulating resin in poor solvent by dripping resin solution into poor solvent and purification in solid state such as washing filtered resin slurry with poor solvent A normal method such as a method can be applied. For example, the resin is precipitated as a solid by contacting a solvent (poor solvent) in which the resin is hardly soluble or insoluble in a volume amount of 10 times or less, preferably 10 to 5 times that of the reaction solution.

The solvent (precipitation or reprecipitation solvent) used in the precipitation or reprecipitation operation from the polymer solution may be a poor solvent for the polymer, and may be a hydrocarbon, halogenated hydrocarbon, nitro, depending on the type of polymer. A compound, ether, ketone, ester, carbonate, alcohol, carboxylic acid, water, a mixed solvent containing these solvents, and the like can be appropriately selected for use. Among these, as a precipitation or reprecipitation solvent, a solvent containing at least an alcohol (particularly methanol or the like) or water is preferable.

  The amount of the precipitation or reprecipitation solvent used can be appropriately selected in consideration of efficiency, yield, and the like, but generally 100 to 10000 parts by mass, preferably 200 to 2000 parts by mass with respect to 100 parts by mass of the polymer solution, More preferably, it is 300-1000 mass parts.

  The temperature for precipitation or reprecipitation can be appropriately selected in consideration of efficiency and operability, but is usually about 0 to 50 ° C., preferably around room temperature (for example, about 20 to 35 ° C.). The precipitation or reprecipitation operation can be performed by a known method such as a batch method or a continuous method using a conventional mixing vessel such as a stirring tank.

  The precipitated or re-precipitated polymer is usually subjected to conventional solid-liquid separation such as filtration and centrifugation, and dried before use. Filtration is performed using a solvent-resistant filter medium, preferably under pressure. Drying is performed at a temperature of about 30 to 100 ° C., preferably about 30 to 50 ° C. under normal pressure or reduced pressure (preferably under reduced pressure).

  The resin may be once deposited and separated, and then dissolved again in a solvent, and the resin may be brought into contact with a hardly soluble or insoluble solvent. That is, after completion of the radical polymerization reaction, a solvent in which the polymer is hardly soluble or insoluble is brought into contact, the resin is precipitated (step a), the resin is separated from the solution (step b), and dissolved again in the solvent. (Step c), and then contact the resin solution A with a solvent in which the resin is hardly soluble or insoluble in a volume amount less than 10 times that of the resin solution A (preferably 5 times or less volume). This may be a method including precipitating a resin solid (step d) and separating the precipitated resin (step e).

  Specific examples of the hydrophobic resin (HR) are shown below. Table 1 below shows the molar ratio of repeating units in each resin (corresponding to each repeating unit in order from the left), the weight average molecular weight, and the degree of dispersion.

In the pattern forming method of the present invention, the photosensitive film formed from the photosensitive composition is preferably used at a film thickness of 5 to 300 nm, and preferably at a film thickness of 20 to 200 nm, from the viewpoint of improving resolution. Is more preferable. Such a film thickness can be obtained by setting the solid content concentration in the photosensitive composition to an appropriate range to give an appropriate viscosity and improving the coating property and film forming property.
The total solid content concentration in the photosensitive composition is generally 1 to 20% by mass, more preferably 1 to 15% by mass, and still more preferably 1 to 10% by mass.

  The photosensitive composition of the present invention is used by dissolving the above components in a predetermined organic solvent, preferably the above mixed solvent, filtering the solution, and then applying the solution on a predetermined support as follows. The pore size of the filter used for filter filtration is preferably 0.1 μm or less, more preferably 0.05 μm or less, and still more preferably 0.03 μm or less made of polytetrafluoroethylene, polyethylene, or nylon.

In order to prevent the resist film from coming into direct contact with the immersion liquid between the photosensitive film (hereinafter also referred to as a resist film) of the photosensitive composition of the present invention and the immersion liquid, Hereinafter, the top coat may also be provided. Functions necessary for the top coat are suitability for application to the upper layer of the resist film, transparency to radiation, particularly 193 nm, and poor solubility in immersion liquid. It is preferable that the top coat is not mixed with the resist and can be uniformly applied to the upper layer of the resist.
From the viewpoint of 193 nm transparency, the top coat is preferably a polymer that does not contain abundant aromatics. Specifically, the polymer contains a hydrocarbon polymer, an acrylate polymer, polymethacrylic acid, polyacrylic acid, polyvinyl ether, and silicon. Examples thereof include a polymer and a fluorine-containing polymer. The aforementioned hydrophobic resin (HR) is also suitable as a top coat. From the viewpoint of contaminating the optical lens when impurities are eluted from the top coat into the immersion liquid, it is preferable that the residual monomer component of the polymer contained in the top coat is small.

When peeling the top coat, a developer may be used, or a separate release agent may be used. As the release agent, a solvent having a small penetration into the resist film is preferable. It is preferable that the peeling process can be performed with an alkali developer in that the peeling process can be performed simultaneously with the resist film development process. From the viewpoint of peeling with an alkaline developer, the topcoat is preferably acidic, but may be neutral or alkaline from the viewpoint of non-intermixability with the resist film.
The resolution is improved when there is no difference in refractive index between the top coat and the immersion liquid. In the case of using water as the immersion liquid in an ArF excimer laser (wavelength: 193 nm), the top coat for ArF immersion exposure is preferably close to the refractive index of the immersion liquid. From the viewpoint of making the refractive index close to the immersion liquid, it is preferable to have fluorine atoms in the topcoat. A thin film is more preferable from the viewpoint of transparency and refractive index.

  The top coat is preferably not mixed with the resist film and further not mixed with the immersion liquid. From this point of view, when the immersion liquid is water, the solvent used for the top coat is preferably a water-insoluble medium that is hardly soluble in the solvent used for the resist composition. Furthermore, when the immersion liquid is an organic solvent, the topcoat may be water-soluble or water-insoluble.

[Examples 1 to 20, Comparative Examples 1 to 4]
<Resin synthesis>
(Resin (A1))
Under a nitrogen stream, 78.1 g of cyclohexanone was placed in a three-necked flask and heated to 80 ° C. Monomer A 18.3 g, monomer B 3.8 g, monomer C 5.5 g, monomer D 11.8 g, polymerization initiator (dimethyl-2,2′-azobis (2-methylpropionate (V-601)) (Manufactured by Wako Pure Chemical Industries, Ltd.) A solution prepared by dissolving 2.418 g in 145.0 g of cyclohexanone was added dropwise over 6 hours, followed by further reaction for 2 hours at 80 ° C. The reaction solution was allowed to cool and then heptane / acetic acid The solution was dropped into an ethyl mixed solution (1290 g / 551 g) over 20 minutes, and the precipitated powder was collected by filtration and dried to obtain 35 g of the desired resin (A1), and the weight average molecular weight (Mw) of the obtained resin was It was 9200 in terms of standard polystyrene, and the dispersity (Mw / Mn) was 1.55.

(Resin (A2) to (A16))
Resins (A2) to (A16) were synthesized using the same method as the synthesis method of the resin (A1).
The structural unit and composition ratio (molar ratio) used for the production of the resin (A), and the weight average molecular weight (Mw) and dispersity (Mw / Mn) of the obtained resin (A) are shown in Table 1 below. .

The compounds corresponding to the abbreviations in Table 1 are the compounds shown below.
[Resin unit]

<Preparation of photosensitive composition>
The components shown in Table 2 below were mixed in a propylene glycol monomethyl ether acetate (PGMEA; 1-methoxy-2-acetoxypropane) / propylene glycol monomethyl ether (PGME; 1-methoxy-2-propanol) in a mass ratio of 6/4. A solution having a solid content concentration of 3.5 mass% was prepared by dissolving in a solvent, and this was filtered through a polyethylene filter having a pore size of 0.03 μm to prepare a photosensitive composition (positive resist solution). The prepared positive resist solution was evaluated by the following method.
In addition, the addition amount of resin, an acid generator, an acid diffusibility inhibitor, and surfactant is as follows.
Resin: 50g
Acid generator: 4g
Acid diffusibility inhibitor: 0.12 g
Surfactant (PF6320 (manufactured by OMNOVA, fluorine-based)): 0.05 g
Solvent: PGMEA / PGME = 60% by mass / 40% by mass

<Evaluation>
An organic antireflection film ARC29A (Nissan Chemical Co., Ltd.) was applied on a silicon wafer and baked at 205 ° C. for 60 seconds to form an antireflection film having a thickness of 78 nm. The prepared photosensitive composition was applied thereon, and baked at 100 ° C. for 60 seconds to form a resist film having a thickness of 100 nm. The obtained wafer ArF excimer laser scanner (PAS5500 / 1100 manufactured by ASML, NA0.75) was used to expose through a 6% halftone mask with a 72 nm 1: 1 line and space pattern. After heating at an arbitrary PEB temperature for 60 seconds, developing with an aqueous tetramethylammonium hydroxide solution (2.38% by mass) for 30 seconds, rinsing with pure water, spin drying, and post-baking at an arbitrary temperature for 90 seconds A post resist pattern was obtained.

[Exposure latitude (EL)]
The exposure amount that reproduces a line-and-space mask pattern with a line width of 72 nm is taken as the optimum exposure amount, and when the exposure amount is changed, an exposure amount width that allows a pattern size of 72 nm ± 10% is obtained, and this value is optimum exposure. Divided by the amount and expressed as a percentage. The larger the value, the smaller the change in performance due to the change in exposure amount, and the better the exposure latitude (EL).
[LWR evaluation]
In the standard resist evaluation, the line pattern finished to 72 nm was observed with a scanning microscope (S9380 manufactured by Hitachi, Ltd.), and the distance between both edges in the vertical direction of the line pattern in the range of 2 μm edge in the longitudinal direction of the line pattern. Was measured 50 points, the standard deviation was obtained, and 3σ was calculated. A smaller value indicates better performance.
〔Glass-transition temperature〕
The Tg of the resin shown in Table 2 was determined by heating the resin sample at a rate of 20 ° C./min from room temperature by DSC method, measuring the calorific value with a differential scanning calorimeter, Two extension lines were drawn on the exothermic curve), and Tg was determined from the intersection of the 1/2 line between the extension lines and the endothermic curve.

(Acid diffusion inhibitor)
X-1: 2,6-diisopropylaniline X-2: 2-phenylbenzimidazole X-3: Tri-n-octylamine

  As shown in Table 2, it was confirmed that the combination of the photosensitive composition of the present invention and the pattern formation process was superior in exposure latitude and LWR as compared with the patterns shown in Comparative Examples 1 to 4. Furthermore, in the sulfonic acid generator that generates sulfonic acid contained in the photosensitive composition, by using a structure that does not contain a benzene ring structure in the generated acid generated by irradiation with actinic rays or radiation, an optimum exposure amount can be obtained. High sensitivity was achieved.

Example 21
Further, a photosensitive composition was prepared and coated in the same manner as in Example 5 except that 0.10 g of the following polymer was added as a hydrophobic resin to obtain a resist film. Further, the obtained resist film was subjected to pattern exposure with an ArF excimer laser immersion stepper (NA 0.85) using ultrapure water as an immersion liquid to form a pattern in the same manner as in Example 1, and the LWR and It was confirmed that the exposure latitude performance was reproduced.

[Example 22]
Further, a photosensitive composition was prepared and coated in the same manner as in Example 1 except that 0.10 g of the following polymer was added as a hydrophobic resin to obtain a resist film. Further, the obtained resist film was subjected to pattern exposure using an ArF excimer laser immersion stepper (NA 0.85) using ultrapure water as an immersion liquid, and a pattern was formed in the same manner as in Example 1 to perform LWR and exposure. It was confirmed that the latitude performance was reproduced.

  As described above, it was confirmed from Examples 21 and 22 that the photosensitive composition of the present invention can be suitably used for pattern formation by ArF excimer laser immersion exposure.

Example 23
When the pattern formed in Comparative Example 1 was further heated at 140 ° C./60 seconds, a pattern with an exposure latitude (EL) of 13.3% and an LWR of 5.8 nm was obtained. It was confirmed that only the LWR performance could be improved without deteriorating the exposure latitude performance.

Claims (4)

A pattern forming method including a step of forming a photosensitive film with a photosensitive composition, a step of irradiating the photosensitive film with actinic rays or radiation, a heating step (PEB step), a developing step, a rinsing step, and a post-baking step The pattern forming method is characterized in that the glass transition temperature of at least one resin contained in the photosensitive composition is in the range of the formula (1).
Formula (1): Heating temperature in the post-baking process + 20 ° C. ≧ glass transition temperature of the resin> heating temperature in the PEB process   The pattern forming method according to claim 1, wherein the heating temperature in the PEB process is 115 ° C. or lower, and the heating temperature in the post-baking process is 115 ° C. or higher.   The pattern forming method according to claim 1, wherein the photosensitive film has a thickness in a range of 5 nm to 300 nm. The pattern forming method according to any one of claims 1 to 3, comprising a resin that satisfies a condition of a heating temperature in a post-baking step + 20 ° C ≥ a glass transition temperature of the resin> a heating temperature in the PEB step. The photosensitive composition used in.