JP2014012807A - Resin composition for forming pattern and pattern forming process - Google Patents

Abstract

Provided is a resin composition for pattern formation that can form a sea-island structure consisting of an island part phase-separated into a hole in a hole and a sea part surrounding it.
Hole shrink pattern formation comprising a block copolymer I containing an aromatic ring-containing polymer a and a (meth) acrylate polymer b and a (meth) acrylate polymer II composed of repeating units of the (meth) acrylate polymer b W _I / W _II ≧ 1 when the mass of the block copolymer I is W _I and the mass of the (meth) acrylate polymer II is W _II, and the mass of the aromatic ring-containing polymer a is W _a , when the mass of the (meth) acrylate polymer b is W _b , 1 ≦ W _a / W _b ≦ 9, the number average molecular weight of the (meth) acrylate polymer b is M _{n (b),} and (meth) It is _{0.01 ≦ M n (II) /} M n (b) ≦ 2 when the number average molecular weight of acrylate polymer (II) was _{M n (II)} Narubutsu.
[Selection figure] None

Description

  The present invention relates to a resin composition for pattern formation of a nanoscale structure. More specifically, the present invention relates to a pattern-forming resin composition capable of forming a sea-island structure composed of island portions phase-separated in a cylindrical shape in a hole and a sea portion surrounding the island portion.

According to the International Semiconductor Technology Roadmap (ITRS), it is said that fine processing technology exceeding 22 nm node will be required in 2014. However, it is expected that exceeding the 22 nm node using conventional photolithography is difficult even if a complicated double patterning process or an expensive EUV exposure apparatus is used.
In recent years, attention has been focused on a method of forming a smaller pattern by using DSA (Directed Self-Assembly) using a block copolymer. DSA is a technique that is expected to increase the resolution compared to the original pattern by forming a microphase separation structure of a block copolymer on a substrate patterned by lithography. As described in Patent Document 1 below, for example, a DSA technique is used to embed polystyrene (PS) -block-polymethyl methacrylate (PMMA) in a hole having a critical dimension (CD) of 60 nm to 110 nm, and self-organization. It has been studied that PMMA forms a micro phase separation structure at the center of a hole to manufacture a hole shrink.

JP 2010-269304 A

The inventor of the present application forms a microphase separation structure when a block copolymer is embedded in a hole and performs a specific treatment. However, a plurality of phase separations may occur in the hole (opening), and a plurality of sea island structures may be formed. (See FIG. 1 (a)). That is, according to the prior art, it has been found that a desired hole shrink may not be formed, and that homogeneous phase separation may not occur in a plurality of holes.
In view of such a situation, the problem to be solved by the present invention is to form a homogeneous phase separation structure in a plurality of holes, and to form an island portion that is phase-separated into a single cylindrical shape in the hole and a sea portion surrounding it. It is providing the resin composition for pattern formation which can form the sea island structure which consists of (refer FIG.1 (b)).

As a result of intensive studies and experiments, the inventor has added a specific polymer in a specific ratio to a block copolymer of the prior art, thereby forming a single cylinder without forming a plurality of sea-island structures in the hole. A sea-island structure consisting of island portions that are phase-separated in a shape and a sea portion surrounding them is formed, thereby unexpectedly discovering that a hole shrink can be formed at the center of the hole. It came to complete.
That is, the present invention is as follows.

[1] A (meth) acrylate polymer comprising a block copolymer (I) containing an aromatic ring-containing polymer (a) and a (meth) acrylate polymer (b), and a repeating unit of the (meth) acrylate polymer (b) ( II) and at least a resin composition for forming a pattern for hole shrinking, wherein the mass of the block copolymer (I) is W _I and the mass of the (meth) acrylate polymer (II) is W _II W _I / W _II ≧ 1, where W _{a is} the mass of the aromatic ring-containing polymer (a), and W _b is the mass of the (meth) acrylate polymer (b), 1 ≦ W _a / W _b ≦ 9 and is, and the a (meth) number average molecular weight _{M n} of acrylate polymer (b) _(b), the (meth) acrylate polymer (II Number when the average molecular weight was _{M n (II),} said composition characterized in that it is _{0.01 ≦ M n (II) /} M n (b) ≦ 2 in.

  [2] The resin composition for pattern formation according to [1], wherein the aromatic ring-containing polymer (a) constituting the block copolymer (I) is polystyrene.

  [3] The pattern forming resin composition according to [1] or [2], wherein the block copolymer (I) is a diblock copolymer of polystyrene and polymethyl methacrylate.

[4] The pattern-forming resin composition according to any one of [1] to [3], wherein the block copolymer (I) has a number average molecular weight ( _{Mn (I)} ) of 500,000 or less.

  [5] A pattern-forming solution containing the pattern-forming resin composition according to any one of [1] to [4] and a solvent, wherein a mass ratio of the resin composition to the solution is 0.1 to 0.1. The pattern forming solution which is 30% by mass.

  [6] When the critical dimension (CD) is less than 200 nm, the circular or minor axis is a, and the major axis is b, the pattern forming solution described in [5] is 1 < A method for producing a hall shrink, comprising: applying onto a substrate having a plurality of individual openings having an oval shape of b / a ≦ 5, filling the openings with the solution, and then removing the solvent.

  According to the present invention, without forming a plurality of sea-island structures in a hole (opening), a sea-island structure including an island part phase-separated into a single cylinder and the sea part surrounding it is generated at the center of the hole. This makes it possible to form a homogeneous hole shrink.

It is the schematic explaining the improvement effect in hall shrink manufacture. (A) shows a state in which a plurality of sea-island structures are formed in a hole (opening). (B) shows the sea island structure which consists of the island part phase-separated into one cylinder shape formed in the hole center part by this invention, and the sea part surrounding it. It is the schematic of the hall shrink manufacturing process which concerns on this invention.

Hereinafter, the resin composition for pattern formation which concerns on this invention is demonstrated in detail.
The resin composition for pattern formation according to the present invention comprises a block copolymer (I) containing an aromatic ring-containing polymer (a) and a (meth) acrylate polymer (b), and a (meth) acrylate polymer ( (meth) acrylate polymer (II) containing the monomer which comprises b).

[Block copolymer (I)]
The block copolymer (I) contained in the resin composition for pattern formation according to the present invention includes an aromatic ring-containing polymer (a) and a (meth) acrylate polymer (b).
The ratio of the monomer unit of the aromatic ring-containing polymer part (a) and the (meth) acrylate polymer part (b) to the entire block copolymer (I) can be 50 mol% or more.
Further, when the mass of the aromatic ring-containing polymer (a) is W _a and the mass of the (meth) acrylate polymer (b) is W _b , 1 ≦ W _a / W _b ≦ 9.
In the present invention, when phase separation is performed using the resin composition for pattern formation, the (meth) acrylate polymer (b) derived from the block copolymer (I) and the (meth) acrylate polymer (II) are cylindrical island phases. And the lower limit of W _a / W _b is 1 or more, preferably 2 or more so that the aromatic ring-containing polymer (a) part derived from the block copolymer (I) is a sea phase so as to surround the island phase. . On the other hand, the upper limit of W _a / W _b is 9 or less, preferably 6 or less.
The number average molecular weight of the block copolymer (I) used in the present invention is 500,000 or less, preferably 300,000 or less, more preferably 200,000 or less from the viewpoint of forming a fine pattern, and the (meth) acrylate polymer (II ) And (meth) acrylate polymer (b) of block copolymer (I), and a portion of block copolymer (I) comprising an aromatic ring-containing polymer (a) are phase-separated from 20,000 That's it.

Next, the constituent components of the resin composition for pattern formation according to the present invention will be described in detail.
First, the block copolymer (I) will be described.
The aromatic ring-containing polymer (a), which is one of the essential components of the block constituting the block copolymer (I) used in the present invention, is a homopolymer of a vinyl monomer having a heteroaromatic ring such as an aromatic ring or a pyridine ring. Yes, for example, polystyrene (hereinafter also referred to as PS), polymethylstyrene, polyethylstyrene, polyt-butylstyrene, polymethoxystyrene, polyN, N-dimethylaminostyrene, polychlorostyrene, polybromostyrene, poly Examples include trifluoromethylstyrene, polytrimethylsilylstyrene, polydivinylbenzene, polycyanostyrene, poly α-methylstyrene, polyvinyl naphthalene, polyvinyl biphenyl, polyvinyl pyrene, polyvinyl phenanthrene, polyisopropenyl naphthalene, polyvinyl pyridine, etc. It is possible. Here, the aromatic ring-containing polymer that is more preferably used in the present invention is polystyrene from the viewpoint of excellent phase separation, availability of raw material monomers, and ease of synthesis.

  The (meth) acrylate polymer (b), which is another essential component of the block constituting the block copolymer (I) used in the present invention, is at least one kind selected from the group consisting of the following acrylate monomers and methacrylate monomers. It is a polymer or a copolymer. Examples of the group consisting of acrylate monomers and methacrylate monomers that can be used here include methyl methacrylate (hereinafter also referred to as MMA), ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, and n-butyl methacrylate. , Isobutyl methacrylate, t-butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, acrylic Examples thereof include t-butyl acid, n-hexyl acrylate, cyclohexyl acrylate, and the like. The poly (meth) acrylate used most preferably in the present invention is a methyl methacrylate homopolymer polymethyl methacrylate (from the viewpoint of excellent phase separation, availability of raw material monomers, and ease of synthesis. Hereinafter, it is also referred to as polymethyl methacrylate or PMMA.)

The block copolymer (I) used in the present invention is a diblock, triblock or more multiblock in which one end or both ends of the aromatic ring-containing polymer and one end or both ends of the poly (meth) acrylate are bonded. From the viewpoint of ease of synthesis, the copolymer is preferably a diblock copolymer in which one end of an aromatic ring-containing polymer and poly (meth) acrylate are bonded to each other, more preferably polystyrene (PS) and polymethyl methacrylate. (PMMA) diblock copolymer.
In addition to the aromatic ring-containing polymer part (a) and poly (meth) acrylate part (b), the block copolymer (I) contains other polymer component blocks in a proportion not exceeding 50 mol% in terms of monomer units. Can also be included. That is, as described above, the resin composition for pattern formation according to the present invention is the total of the aromatic ring-containing polymer part (a) and the poly (meth) acrylate part (b) with respect to the entire block copolymer (I). The ratio is 50 mol% or more in monomer units. Specific examples of other polymer components include polyethylene oxide, polypropylene oxide, polytetramethylene glycol, and the like.

The block copolymer (I) can be synthesized by living anion polymerization, living radical polymerization, or coupling of polymers having reactive end groups. For example, in living anionic polymerization, an aromatic ring-containing polymer is first synthesized by synthesizing an aromatic ring-containing polymer using an anionic species such as butyl lithium as an initiator, and then polymerizing a (meth) acrylate monomer using the terminal as an initiator. Block copolymers of polymers and poly (meth) acrylates can be synthesized. At this time, the number average molecular weight of the resulting polymer can be increased by lowering the amount of initiator added, and the number average molecular weight of the polymer can be set as designed by removing impurities in the system such as water and air. Can be controlled. Moreover, when superposing | polymerizing a poly (meth) acrylate part, a side reaction can be suppressed by reducing the temperature of a system to 0 degrees C or less. In living radical polymerization, first, a halogen compound such as bromine is added to the double bond of the (meth) acrylate monomer, the terminal is halogenated, and poly (meth) acrylate is synthesized using a copper complex as a catalyst. A block copolymer (I) of an aromatic ring-containing polymer (a) and a poly (meth) acrylate (b) can be obtained by synthesizing an aromatic ring-containing polymer.
Alternatively, an aromatic ring-containing polymer is synthesized by living anionic polymerization, and the terminal is halogenated, and then a (meth) acrylate monomer is reacted in the presence of a copper catalyst, and the aromatic ring-containing polymer (a) and poly (meth) acrylate ( The block copolymer (I) of b) can also be synthesized.

Coupling of polymers having reactive end groups described above is, for example, an aromatic ring-containing polymer obtained by reacting an aromatic ring-containing polymer having an amino group at the terminal with a poly (meth) acrylate having maleic anhydride at the terminal. A method of preparing a block copolymer (I) of (a) and poly (meth) acrylate (b) can be mentioned.
The number average molecular weight of the block copolymer (I) is determined by the following method. First, the number average molecular weight of the aromatic ring-containing polymer (a) portion is measured by the following method (1), and then the number average molecular weight of the poly (meth) acrylate (b) portion by the following method (2). Measure. When the block copolymer (I) is composed only of the aromatic ring-containing polymer (a) portion and the poly (meth) acrylate (b) portion, the number average molecular weight of the block copolymer (I) is the fragrance obtained in (1). It is calculated as the sum of the number average molecular weight of the ring-containing polymer (a) portion and the number average molecular weight of the poly (meth) acrylate (b) portion obtained in (2).
Alternatively, when the block copolymer (I) includes an aromatic ring-containing polymer (a) part, a poly (meth) acrylate (b) part, and other polymer parts, (3) other Measurement is performed by a method for measuring the number average molecular weight of the polymer portion. In this case, the number average molecular weight of the block copolymer (I) is the same as the number average molecular weight of the aromatic ring-containing polymer (a) portion obtained in (1) and the poly (meth) acrylate (2). b) Calculated as the sum of the number average molecular weight of the portion and the number average molecular weight of the other polymer portion obtained in (3).

(1) Method for measuring the number average molecular weight of the aromatic ring-containing polymer (a) portion in the block copolymer (I) When the block copolymer (I) is synthesized by living anionic polymerization, generally the aromatic ring-containing monomer is first polymerized. The (meth) acrylic monomer is polymerized from the end. When the aromatic ring-containing monomer is polymerized, a part thereof is taken out and the reaction is stopped, so that the aromatic ring-containing polymer in the block copolymer (I) ( a) Only part can be obtained. The aromatic homopolymer thus obtained is measured for elution time distribution using gel permeation chromatography (hereinafter also referred to as GPC). Next, the elution time of several kinds of standard polystyrenes having different number average molecular weights is measured, and the elution time is converted into the number average molecular weight.

(2) Method of measuring number average molecular weight of poly (meth) acrylate (b) moiety in block copolymer (I) The block copolymer is dissolved in a deuterated solvent such as deuterated chloroform, and ¹ H NMR spectrum is measured. At that time, by comparing the number of protons derived from the aromatic ring-containing polymer and the number of protons derived from the poly (meth) acrylate, the aromatic ring-containing polymer (a) portion in the block copolymer (I) and the poly (meth) acrylate ( b) The molar ratio of the part can be determined. Therefore, as described above, the number average molecular weight of the poly (meth) acrylate (b) portion can be determined from the number average molecular weight of the aromatic ring-containing polymer (a) portion determined in advance by GPC.

(3) Method for measuring number average molecular weight of other polymer portion in block copolymer (I) The block copolymer is dissolved in a deuterated solvent such as deuterated chloroform, and a ¹ H NMR spectrum is measured. At that time, by comparing the number of protons derived from the aromatic ring-containing polymer and the number of protons derived from the other polymer part, the molar ratio of the aromatic ring-containing polymer part and the other polymer part in the block copolymer in the monomer unit is obtained. It is done. Therefore, as described above, the number average molecular weight of the other polymer portion can be obtained from the number average molecular weight of the aromatic ring-containing polymer obtained in advance by GPC.

[(Meth) acrylate polymer (II)]
The resin composition for pattern formation which concerns on this invention is characterized by further adding (meth) acrylate polymer (II) to said block copolymer (I). Hereinafter, the (meth) acrylate polymer (II) will be described.
In the present invention, when the mass of the block copolymer (I) is W _I and the mass of the (meth) acrylate polymer (II) is W _II , the mass ratio is W ₁ / W _II ≧ 1. This is a condition required from the viewpoint of preventing macrophase separation, and W ₁ / W _II is more preferably 1.5 or more.
In the present invention, the number average molecular weight ( _{Mn (II)} ) of the (meth) acrylate polymer (II) to be added and the number average molecular weight of the (meth) acrylate polymer (b) constituting the block copolymer (I) ( M _{n (b)} ) must have a relationship of 0.01 ≦ M _{n (II)} / M _{n (b)} ≦ 2.
From the viewpoint of preventing macrophase separation, the upper limit of M _{n (II)} / M _{n (b)} is preferably 2 or less, more preferably 1.1 or less. On the other hand, in order to form a sea-island structure consisting of one island in the sea, the lower limit is 0.01 or more, preferably 0.1 or more, and more preferably 0.15 or more.

The poly (meth) acrylate polymer (II) has a homopolymer as a main component.
The poly (meth) acrylate polymer (II) can be synthesized by anionic polymerization or radical polymerization. In anionic polymerization, for example, an anionic species such as butyllithium can be reacted with diphenylethylene, and a poly (meth) acrylate monomer can be polymerized using a diphenylethylene terminal as an initiator. In radical polymerization, for example, polymerization can be performed by using 2,2′-azobis (isobutyronitrile) or 2,2′-azobis (dimethyl isobutyrate) as a polymerization initiator and using methyl ethyl ketone as a solvent. it can.
The number average molecular weight of the poly (meth) acrylate polymer (II) can be determined by the following measuring method.
First, the elution time distribution of the poly (meth) acrylate polymer (II) is measured using GPC. Next, elution times of several types of standard PMMA having different number average molecular weights are measured, and the elution times are converted into number average molecular weights. From this result, the number average molecular weight can be determined.
As long as the formation of a desired Shanghai island structure is not hindered, anything other than the above-described components may be added to the resin composition for pattern formation according to the present invention.

Hereinafter, a method for producing hole shrink using the resin composition for pattern formation of the present invention will be described.
The pattern forming resin composition according to the present invention can be dissolved in a solvent to form a pattern forming solution. Any solvent can be used as long as it can dissolve the resin composition for pattern formation. For example, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, cyclohexane Pentanone, cyclohexanone, isophorone, N, N-dimethylacetamide, dimethylimidazolinone, tetramethylurea, dimethyl sulfoxide, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol Monomethyl ether, propylene glycol monomethyl ether acetate (hereinafter also referred to as PGMEA), methyl lactate, lactate ester , Butyl lactate, methyl-1,3-butylene glycol acetate, 1,3-butylene glycol-3-monomethyl ether, and methyl-3-methoxypropionate. These may be used alone or in combination of two or more. It can be used as a solvent. Specific examples of more preferable solvents include N-methylpyrrolidone, cyclopentanone, cyclohexanone, γ-butyrolactone, ethyl lactate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and PGMEA. The mass ratio of the resin composition to the solution is preferably 0.1 to 30% by mass from the viewpoint of forming a thin film.

The resin composition solution prepared as described above is filled into one or a plurality of openings arranged on the substrate in advance, and a hall shrink is manufactured through a subsequent phase separation process.
The substrate includes an organic material, an inorganic material, a metal material, and the like, and is not limited to a substrate used in the semiconductor industry, but a silicon wafer or the like is preferable among the substrates used for semiconductor applications.
The shape of the opening on the substrate is not limited to a circle, an ellipse, or a polygon, but a circle is preferable in the manufacture of hole shrink. Moreover, an elliptical hole can be manufactured by hole-shrinking an elliptical or rectangular opening. The upper limit of the diameter (critical dimension) of the circular opening can be less than 200 nm, preferably 100 nm or less, while the lower limit can be 20 nm or more, preferably 30 nm or more. When the minor axis of the oval opening is a and the major axis is b, the upper limit of a can be 100 nm or less, preferably 80 nm or less, more preferably 60 nm or less, and the ratio of a and b is 1 < b / a ≦ 5, preferably 1.1 ≦ b / a ≦ 4.5, more preferably 1.2 ≦ b / a ≦ 4.
The upper limit of the depth of the opening can be 300 nm or less, preferably 200 nm or less, and the lower limit can be 10 nm or more, preferably 30 nm or more. From the viewpoint of ease of phase separation when the resin composition of the present invention phase-separates, the material constituting the opening on the substrate may be organic, inorganic, metal, or any material. Organic and inorganic substances are preferred.
The performance of hole shrink is not limited to the number of holes in the plane.
The above-mentioned opening refers to a hole on the order of nm formed on the substrate by photolithography or the like, and is also referred to as a hole or a pre-pattern. Here, the method of creating the opening is not limited to photolithography.

Next, a method for forming hole shrink will be described.
In the present invention, the term “hole shrink” refers to further reducing the diameter of the opening provided in advance on the substrate.
In the formation of the hole shrink using the resin composition for pattern formation of the present invention, at least a step of filling the above-mentioned pattern formation solution in one or a plurality of openings arranged on the substrate by a coating method or the like, heating is performed. The steps are performed in order.
As a filling method, the pattern forming solution is applied by a spin coater, a bar coater, a blade coater, a curtain coater, a spray coater, an ink jet method, a filling method, a screen printing machine, a gravure printing machine, an offset printing machine, etc. The method of filling with can be mentioned. From the viewpoint of easy control of the film thickness, spin coating is preferred, and the rotation speed is preferably 30 rpm to 5000 rpm.
Next, the substrate in which the opening is filled with the pattern forming coating solution is dried by heating or vacuum drying using an air dryer, an oven, a hot plate or the like to remove the solvent.

The method for removing the solvent can be roughly classified into a method of transferring heat directly from the lower side of the substrate like a hot plate and a method of convection of a high-temperature gas like an oven. Direct heat transfer is preferable because phase separation proceeds in a shorter time and a sea-island structure can be obtained.
After removing the solvent, heat treatment is performed to form a sea-island structure. The heating temperature is preferably 130 ° C. or higher and 280 ° C. or lower, more preferably 140 ° C. or higher and 270 ° C. or lower, and further preferably 150 ° C. or higher and 260 ° C. or lower. The heating time is 10 seconds or more and 100 hours or less, preferably 10 hours or less, and more preferably 1 hour or less. In the case of direct heat transfer, it is preferably from 10 seconds to 1 hour, more preferably from 10 seconds to 30 minutes. If the heating temperature is 130 ° C. or higher, a phase separation structure can be formed higher than Tg, and if it is 280 ° C. or lower, polymer decomposition is suppressed. In the case of direct heat transfer, a phase separation structure can be formed if the heating time is 10 seconds or longer, and decomposition of the polymer is suppressed if it is 1 hour or shorter. The sea-island structure pattern can be obtained in a shorter time as the heating temperature is higher. In the present invention, a sea-island pattern is obtained in which the aromatic ring-containing polymer is the sea and the poly (meth) acrylate polymer is the island.
The atmosphere during the heat treatment is not particularly limited, such as Air, nitrogen, or vacuum.

When the above operation is performed, the resin composition for pattern formation proceeds from the phase separation in the opening, and is derived from the island portion (block copolymer (I) phase-separated into one cylindrical shape without forming a plurality of sea-island structures. (Meth) acrylate polymer (b) and (meth) acrylate polymer (II) are formed at the center of the opening to form and surround the sea portion (containing aromatic ring derived from block copolymer (I)) A sea-island structure composed of polymer (a)) is formed.
In order to make a hole shrink, it is necessary to remove the phase-separated cylindrical island portion by etching. Examples of the etching method include a dry etching method and a wet etching method (such as a UV exposure method and an electron beam exposure method).
By removing the cylindrical island portion thus phase-separated by etching, the opening on the substrate can be made smaller than the initial diameter.

The outline of the etching method in the present invention will be described below with reference to FIG.
First, a solution obtained by dissolving the pattern forming resin composition of the present invention in an organic solvent is applied to the layer (i) having an opening disposed on the substrate (ii) by a spin coating method, and this is applied to a hot plate. The opening is filled with the resin composition for pattern formation (iii) by performing heat treatment until the organic solvent is removed (step (1)). Thereafter, the pattern forming resin composition is phase-separated by heat treatment (annealing) in a oven or on a hot plate at a temperature higher than the glass transition temperature of the polymer species constituting the pattern forming resin composition (step (2) )). At this time, the obtained phase separation pattern is a cylinder pattern oriented perpendicular to the substrate (ii), and the resin forming the cylinder part is (meth) acrylate polymer (b) derived from the block copolymer (I). (Meth) acrylate polymer (II) (denoted by (iv) in FIG. 2). (V) around (iv) is the aromatic ring-containing polymer (a) derived from the block copolymer (I). Since the (meth) acrylate polymer ((iv) in FIG. 2) has a lower etching resistance than the aromatic ring-containing polymer (v), (iv) constituting the cylinder part is selectively removed by etching (step ( 3)).
Subsequently, the pattern is transferred by dry etching or wet etching of the layer (ii) using (i) and (v) as a mask (step (4)).

Hereinafter, synthesis examples of the block copolymer (I) and the poly (meth) acrylate homopolymer (II) will be specifically described.
[Synthesis Example 1: Synthesis of block copolymer (I)]
In a 2 L flask, 490 g of dehydrated and degassed tetrahydrofuran (hereinafter also referred to as THF) as a solvent, and a hexane solution (about 0.16 mol / L) of n-butyllithium (hereinafter also referred to as n-BuLi) as an initiator. ): 2.23 mL, dehydrated and degassed styrene as monomer: 20.8 g was added, stirred for 30 minutes while cooling to −78 ° C. in a nitrogen atmosphere, and then dehydrated and degassed methyl methacrylate as the second monomer : 9 g was added and stirred for 2 hours. Thereafter, the reaction solution was added to a container containing 3 L of methanol while stirring, and the precipitated polymer was vacuum-dried overnight at room temperature.
After the polymerization of styrene was completed, 3 ml of the reaction solution was collected before adding MMA. GPC analysis identified the polystyrene with a number average molecular weight of 114,000.
<Method for measuring number average molecular weight of polymer>
The number average molecular weight of the polymer was measured using the following GPC (gel permeation chromatography) apparatus, column, and standard polystyrene.
Device: HLC-8220 manufactured by Tosoh Corporation
Eluent: Chloroform 40 ° C
Column: Tosoh Corporation, trade name: TSKgel SuperHZ2000, TSKgel SuperHZM-N series
Flow rate: 1.0ml / min
Standard substance for molecular weight calibration: TSK standard polystyrene (12 samples) manufactured by Tosoh Corporation

<Measurement method of ratio of block part of block copolymer (I)>
From the results of analysis of the measured values obtained using the following nuclear magnetic resonance (NMR) apparatus, the molar ratio of the PS part and the PMMA part of the block copolymer (I) was obtained. The NMR apparatus and solvent used are as follows.
Apparatus: JNM-GSX400 FT-NMR manufactured by JEOL Ltd.
Solvent: heavy dichloroethylene Combined with the GPC results described above, the block copolymer, the main product, was identified as having a number average molecular weight of 114,000 for the PS moiety and a number average molecular weight of 50,000 for the PMMA moiety. The obtained block copolymer was designated as BC-1.
BC-2 and BC-3 were synthesized in the same manner as in Synthesis Example 1 except that the amounts of monomers and initiator used were changed. BC-2 is identified with a PS moiety number average molecular weight of 100,000 and a PMMA moiety with a number average molecular weight of 67,000, BC-3 is PS moiety with a number average molecular weight of 47,000 and the number of PMMA moieties. The average molecular weight was identified as 32,000. The amounts of initiator and monomer used in the synthesis are shown in Table 1 below.

[Synthesis Example 2: Synthesis of poly (meth) acrylate homopolymer (II)]
Diphenylethyllithium in which 2 L flask was reacted with dehydrated and degassed THF: 0.5 L, diphenylethylene: 0.8 ml as an initiator and n-BuLi hexane solution (about 1.65 mol / L): 2.73 mL 47 ml of dehydrated and degassed methyl methacrylate as a monomer was added and stirred for 30 minutes while cooling to -78 ° C. under vacuum. Thereafter, the polymerization was stopped with methanol, and a polymer was precipitated from methanol. The reprecipitated polymer was vacuum dried at room temperature for 24 hours. As a result, polymethyl methacrylate having a number average molecular weight of 11,000 was obtained. The obtained homopolymer was designated as PMMA-1. (At this time, the GPC was measured under the same conditions as the block copolymer BC-1, but the standard PMMA M-H-10 (10 samples) manufactured by Polymer Laboratories was used as the standard substance for molecular weight calibration).

[Synthesis Example 3]
Polymethyl methacrylate was synthesized and characterized in the same manner as in Synthesis Example 2 except that 40 ml of methyl methacrylate, 0.13 ml of diphenylethylene, and 0.45 ml of n-BuLi were used. As a result, polymethyl methacrylate (PMMA-2) having a number average molecular weight of 54,000 was obtained.

[Synthesis Example 4]
Methyl ethyl ketone: 390 g as a solvent in a 1 L flask, 37 g of 2,2′-azobis (dimethyl isobutyrate) as an initiator, and methyl methacrylate: 65 g as a monomer were placed in a nitrogen stream, stirred at 70 ° C. for 5 hours, and then stirred. Allowed to cool to room temperature.
This reaction mixture was added to 3 L of hexane to precipitate a polymer. As a result of vacuum-drying the filtered solid content overnight, polymethyl methacrylate (PMMA-3) having a number average molecular weight of 2,300 was obtained.

[Example 1]
BC-1 obtained in the above synthesis example and a PGMEA 1.5% by mass solution of PMMA-1 were respectively prepared, and 8 g of the obtained BC-1 solution and 2 g of the PMMA-1 solution were mixed. Was prepared. The W _I / W _II of this solution was 4, W _a / W _b was 2.33, and M _{n (II)} / M _{n (b)} was 0.22.
This solution was spin-coated on a substrate having a hole having a circular hole diameter (critical dimension) of 130 nm and prebaked at 110 ° C. for 90 seconds to embed the polymer composition in the hole. Subsequently, it heat-processed for 10 minutes on the hot plate made from ASONE company set to 190 degreeC, and cooled to room temperature. This wafer was subjected to O ₂ plasma etching using a plasma etching apparatus EXAM (manufactured by Shinko Seiki Co., Ltd.) at a pressure of 30 Pa and a power of 133 W, and a field emission scanning electron microscope (FE-SEM) S-4800 (Hitachi Co., Ltd.). When the surface was observed with a high technology, only one shrink hole was found in the pre-pattern, and the hole diameter was 50 nm.

[Example 2]
Except for using 8 g and 2 g of PGMEA 1.5 mass% solutions of BC-1 and PMMA-2 obtained in the above synthesis example (that is, PMMA-2 was used instead of PMMA-1), The same operation as in Example 1 was performed. W _I / W _II of this solution was 4, W _a / W _b was 2.33, and M _{n (II)} / M _{n (b)} was 1.08.
When observed in the same manner as in Example 1, only one shrinked hole was confirmed in the pre-pattern, and the hole diameter was 50 nm.

[Example 3]
The same operation as in Example 1 was performed except that 6 g and 4 g of PGMEA 1.5 mass% solutions of BC-1 and PMMA-1 obtained in the above synthesis example were used. The W _I / W _II of this solution was 1.5, W _a / W _b was 2.33, and M _{n (II)} / M _{n (b)} was 0.22. When observed in the same manner as in Example 1, only one shrinked hole was confirmed in the pre-pattern, and the hole diameter was 45 nm.

[Comparative Example 1]
The same operation as in Example 1 was performed except that the PGMEA 1.5 mass% solution of PMMA-1 was not used. When observed in the same manner as in Example 1, three holes were observed in the prepattern.

[Example 4]
A solution was prepared by mixing 9 g and 1 g of a PGMEA 1.5 mass% solution of BC-2 obtained in Synthesis Example 1 and PMMA-3 obtained in Synthesis Example 4. W _I / W _II of this solution was 9, W _a / W _b was 1.49, and M _{n (II)} / M _{n (b)} was 0.03.
Example 1 except that this solution was spin-coated on a substrate having an elliptical shape (b / a = 3) with a minor axis of 100 nm and a major axis of 300 nm, and was etched with CF ₄ plasma instead of O ₂ plasma. When the surface was observed by the above operation, only one shrinked hole was confirmed in the pre-pattern, and the minor axis was 40 nm and the major axis was 210 nm.

[Comparative Example 2]
When the same operation as in Example 4 was performed except that the PGMEA 1.5 mass% solution of PMMA-3 was not used, a plurality of holes were observed in the prepattern.

[Example 5]
A solution was prepared by mixing 9 g and 1 g of a PGMEA 1.5 mass% solution of BC-3 obtained in Synthesis Example and PMMA-3 obtained in Synthesis Example 4, respectively. The W _I / W _II of this solution was 9, W _a / W _b was 1.47, and M _{n (II)} / M _{n (b)} was 0.06.
This solution was spin-coated on a substrate having an elliptical shape (b / a = 1.5) having a minor axis of 60 nm and a major axis of 90 nm, and surface observation was performed in the same manner as in Example 4. Only one shrunken hole was confirmed in the pattern, and the minor axis was 25 nm and the major axis was 35 nm.

  According to the present invention, a fine hole shrink can be accurately and easily formed at the center of a hole, and therefore, the present invention can be widely used in fields requiring precision processing, such as the semiconductor field.

Claims (6)

A block copolymer (I) comprising an aromatic ring-containing polymer (a) and a (meth) acrylate polymer (b); a (meth) acrylate polymer (II) composed of repeating units of the (meth) acrylate polymer (b); the a resin composition for forming the Hall shrink containing at least, mass W _I of the block copolymer _(I), when the mass of the (meth) acrylate polymer (II) was W _II, W _I / W _II ≧ 1, when W _{a is} the mass of the aromatic ring-containing polymer (a) and W _b is the mass of the (meth) acrylate polymer (b), 1 ≦ W _a / W _b ≦ 9 There, and the number of the (meth) the number average molecular weight of acrylate polymer (b) and _{M n (b),} the (meth) acrylate polymer (II) When the average molecular weight was _{M n (II),} said composition characterized in that it is _{0.01 ≦ M n (II) /} M n (b) ≦ 2.   The resin composition for pattern formation according to claim 1, wherein the aromatic ring-containing polymer (a) constituting the block copolymer (I) is polystyrene.   The resin composition for pattern formation according to claim 1 or 2, wherein the block copolymer (I) is a diblock copolymer of polystyrene and polymethyl methacrylate. The number average molecular weight ( _{Mn (I)} ) of the said block copolymer (I) is 500,000 or less, The resin composition for pattern formation as described in any one of Claims 1-3.   It is a pattern formation solution containing the resin composition for pattern formation and the solvent as described in any one of Claims 1-4, Comprising: The mass ratio of the said resin composition with respect to the said solution is 0.1-30 mass%. A certain pattern forming solution.   When the critical dimension (CD) is less than 200 nm, the circular shape or the minor axis is a, and the major axis is b, the pattern forming solution according to claim 5 is 1 <b / a ≦ 5. A method for producing a hall shrink, comprising: applying the substrate on a substrate having a plurality of elliptical individual openings, and filling the openings with the solution, and then removing the solvent.

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