HK1065860A - Protecting groups in polymers, photoresists and processes for microlithography - Google Patents

Description

Protective group in polymer, photoresist and method for fine photoetching

Background

1. Field of the invention

The present invention relates to photoimaging, and in particular, to imaging in the manufacture of semiconductor devices using photoresists (positive and/or negative). The present invention also relates to novel fluoropolymer compositions having high UV transparency, particularly at short wavelengths, e.g., 157nm, which are useful as binder resins in photoresists and potentially in a wide variety of other applications.

2. Description of related Art

Polymeric products are used as components of imaging and photosensitive systems, particularly in photoimaging systems, such as l.f. thompson, c.g. willson and m.j. bowden inMicro light Introduction to microligraphy (Introduction to microligraphy)2nd Edition, American Chemical Society, Washington, DC, 1994). In these systems, Ultraviolet (UV) light or other electromagnetic radiation impinges on a material containing a photoactive component, causing a physical or chemical change in the material. Thereby making a usefulOr latent image, which can be processed into an image useful for making semiconductor devices.

While the polymer product itself may be photoactive, typically the photosensitive composition will contain one or more photoactive components in addition to the polymer product. Upon exposure to electromagnetic radiation (e.g., UV light), the photoactive component acts to change the rheological state, solubility, surface properties, refractive index, color, electromagnetic properties, or other such physical or chemical properties of the photosensitive composition as described in the above-mentioned monographs, et al.

Electromagnetic radiation in the extreme ultraviolet or extreme ultraviolet region is required to image very fine features in semiconductor devices at the submicron level. For the manufacture of semiconductor devices, positive photoresists are generally used. UV lithography with 365nm (I-line) using novolak polymers and diazonaphthoquinones as dissolution inhibitors is currently an established technique with a resolution limit of about 0.35-0.30 microns. Photolithography with p-hydroxystyrene polymers in the extreme ultraviolet region at 248nm is a known technique with a resolution limit of 0.35-0.18 nm. Since the lower resolution limit decreases with decreasing wavelength (i.e., resolution limit of 0.18-0.12 microns for 193nm imaging and about 0.07 microns for 157nm imaging), future lithographic processes are strongly driven to proceed at shorter wavelengths. Photolithography using 193nm exposure wavelength (obtained from an Ar-F excimer laser) is the first choice for future microelectronic fabrication with 0.18 and 0.13 μm design dimensions. Photolithography with 157nm exposure wavelength (obtained from a fluorine excimer laser) is the first choice for future microlithography to be much longer (after 193 nm), provided that suitable materials with sufficient transparency and other desirable properties at this very short wavelength can be found. The opacity of conventional near and far uv organic photoresists at 193nm or shorter wavelengths prevents their use at such short wavelengths in a single layer.

Development of photoresist compositions containing one or more protected acidic groups can be catalyzed by an acid or base generated by photolysis of a photoactive compound (PAC) that produces hydrophilic acidic groups. For aqueous development, the choice of the designated protected acidic group is generally based on its acid lability, so that when imagewise exposure produces a photoacid, the acid will catalyze the deprotection and production of the hydrophilic acidic group.

The protected acidic groups will generate acidic groups as hydrophilic groups upon contact with photoacid, and examples of components having such protected acidic groups include, but are not limited to: A) esters capable of forming or rearranging to a tertiary cation, B) esters of lactones, C) acetal esters, D) β -cyclic ketoesters, E) α -cyclic ether esters, F) MEEMA (methoxyethoxyethyl methacrylate) and other esters which are easily hydrolyzed due to ortho-promotion, G) carbonates formed from fluorinated alcohols and tertiary aliphatic alcohols. A) Some specific examples of classes are tert-butyl esters, 2-methyl-2-adamantyl esters, and isobornyl esters. B) Some specific examples of such groups are gamma-butyrolactone-3-yl, gamma-butyrolactone-2-yl, mevalonolactone, 3-methylgamma-butyrolactone-3-yl, 3-tetrahydrofuranyl and 3-oxocyclohexyl. C) Specific examples of such groups are 2-tetrahydropyranyl, 2-tetrahydrofuranyl and 2, 3-propylenecarbonate-1-yl. C) Other examples of classes include esters resulting from the addition of vinyl ethers, for example, ethoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, and acetoxyethoxyethyl vinyl ether.

It has been found that these protecting groups may be subject to volatile generation during exposure due to deprotection prior to the post-exposure heating stage, especially as the exposure wavelength for new imaging systems decreases. The generation of volatiles during exposure is undesirable because these volatiles can cover the exposure apparatus lens, adversely affect its imaging performance, and require expensive cleaning processes. The loss of volatile materials can also cause shrinkage of the imaging area of the photoresist, which can adversely affect imaging quality.

JP 11012326 discloses the following reaction:

this indicates that the lactone ring can be opened by catalysis by the photoacid, but it also clearly indicates that the reaction requires the presence of moisture and that the reaction will terminate in the absence of moisture. In this process water is used as an external reagent for the reaction. A method that does not require an external reagent other than the photoacid generator would be advantageous.

There is a need for protecting groups for polymer photoresist compositions, particularly at 193nm or 157nm, which can be deprotected without volatile generation.

Summary of The Invention

Volatile components are components that evaporate from the polymer component of the photoresist composition, cover the exposed lens, and cause a loss of polymer quality, which can lead to poor image quality. The present invention relates to the incorporation of protecting groups and polar groups (groups to be protected) into a ring structure such that no volatile components are released during deprotection of the polar group by the photo-catalyst and resulting dissolution in the developer. This method can be used for a polymer binder of a photoresist composition and/or a dissolution inhibitor of a photoresist composition.

A first aspect of the present invention provides a photoresist composition comprising:

(a) a protected material comprising:

A. one or more cyclic ether groups having the structural formula I or II:

wherein R is_fAnd R_f' independently represents fluoroalkyl of 1 to about 10 carbon atoms, or taken together as (CF)₂)_aWherein a is an integer of from 2 to about 10, R independently represents a hydrogen atom or a straight chain of from 1 to about 10 carbon atomsOr a branched alkyl group, P is an integer from 0 to about 8; wherein the protected material is substantially free of acid groups having a pKa < 11; and

(Y) one or more cyclic esters having the structure III:

wherein R is₁And R₂Independently represent an unsubstituted straight or branched alkyl group having 1 to 10 carbon atoms; aryl, aralkyl or alkaryl having from 6 to 14 carbon atoms; or a substituted group thereof containing at least one of O, S, N, P or halogen; n is an integer from 1 to about 4; and

(b) a photoactive component.

In a second aspect, the present invention is directed to a method of preparing a photoresist image on a substrate, the method comprising, in order:

(W) forming a layer of photoresist on the substrate, the photoresist layer being prepared from a photoresist composition comprising:

(a) a protected material comprising the following groups:

A. one or more cyclic ether groups having the structural formula I or II:

wherein R is_fAnd R_f' independently represents fluoroalkyl of 1 to about 10 carbon atoms, or taken together as (CF)₂)_aWherein a is an integer from 2 to about 10, R independently represents a hydrogen atom or a straight or branched alkyl group of 1 to about 10 carbon atoms, and P is an integer from 0 to about 8; wherein the protected material is substantially free of acid groups having a pKa < 11; and

(Y) one or more cyclic esters having the structure III:

wherein R is₁And R₂Independently represent an unsubstituted straight or branched alkyl group having 1 to 10 carbon atoms; aryl, aralkyl or alkaryl having from 6 to 14 carbon atoms; or a substituted group thereof containing at least one of O, S, N, P or halogen; n is an integer from 1 to about 4; and

(b) a photoactive component;

(X) imagewise exposing the photoresist layer to form imaged regions and unimaged regions; and

(Y) developing the exposed photoresist layer having imaged areas and non-imaged areas to form a relief image on the substrate.

(A) An example of a cyclic ether group represented is an oxetanyl group having the following structure:

(B) one example of a cyclic ester group represented is a substituted lactone having the structure:

one polymer containing this group can be obtained by incorporating dimethyl tulip lactone monomer (gamma, gamma-dimethyl-alpha-methylene-gamma-butyrolactone). Deprotection of these two types of protecting groups is catalyzed by photoacid without the presence of moisture and without the generation of volatiles.

Detailed description of the preferred embodiments

Protecting group：

The protected material contains a protecting group selected from one or more cyclic ether or cyclic ester groups having the structure A or B described above.

Materials containing cyclic ether groups represented by structural formula I can be prepared, for example, by reacting a compound containing-CH ═ CR as described in WO 2000/066575a2_fR_f' segmented compounds are prepared by oxidation with hypochlorite. The materials containing the cyclic ether protecting group represented by formula II wherein p is 0 can be prepared by reacting the corresponding vinyl ether with hexafluoroacetone, for example, as disclosed in U.S. Pat. No. 3,164,610(1964) or Izv. Akad. Nauk. Ser. Khim.1967, pp 918-. Materials containing cyclic ether groups wherein p is from 0 to about 8 can be prepared by reacting a compound of the formula-O-CHCl-CHR- (CRR)_p-C(R_fR_f') cyclization of the alpha-haloether of OH.

The cyclic ether groups of formula I or II can be converted to fluoroalcohol species of formula I 'and II', respectively, by the action of a heated or catalytic amount of an acid as a result of the following ring opening process:

the cyclic ester that can be converted to a carboxylic acid can be a substituted lactone that is ring-opened in the presence of a strong acid. An example is the polymerizable monomer dimethyl tulip lactone (gamma, gamma' -dimethyl-alpha-methylene-gamma-butyl ester). Such functional groups may also be attached to the non-polymeric structure.

The point of attachment of the protected material to the protecting group in formula I or II should be a carbon atom that is a substituent of the ether ring. At least one point of attachment of the protected material to the protecting group in structure III should be through a saturated carbon atom or R of the structure₁Or R₂。

Protected material：

The substance to be protected may be an adhesive or a dissolution inhibitor.

The binder may be a polymeric binder. Examples include all polymers useful as photoresists, such as those of the types disclosed in WO 00/17712 (published 3/20/2000), WO 00/25178 (published 5/4/2000), and PCT/US00/11539 (filed 4/28/2000), provided that when the protecting group is a cyclic ether represented by structures I and II, the photoresist composition does not contain acidic groups having a pKa < 11, typically a pKa < 12, more typically a pKa < 14, in its unexposed state.

The polymeric binder may be a fluoropolymer. The fluoropolymer may further comprise recurring units derived from at least one ethylenically unsaturated compound comprising functional groups of the structure:

-C(R_f)(R_f′)OR₃

wherein R is_fAnd R_f' are identical or different fluoroalkyl groups having from 1 to about 10 carbon atoms, or together form (CF)₂)_nWherein n is 2 to about 10, R₃Is a hydrogen atom or an acid-labile protecting group, R when the protected material is a cyclic ether group₃Is an acid labile protecting group.

R_fAnd R_fThe fluoroalkyl groups represented by' may be partially fluorinated alkyl groups or perfluorinated alkyl groups (i.e., perfluoroalkyl groups).

In general, R_fAnd R_f' independently of one another, represents fluoroalkyl having 1 to about 10 carbon atoms, or together form (CF)₂)_nWherein n is an integer from 2 to about 10. The term "taken together" means R_fAnd R_f' instead of separate, individual fluorinated alkyl groups, they are joined to form a ring structure of 3 to about 11 carbon atoms, as shown in the following figure for the case of the 5-membered ring:

when R is_fAnd R_f' is a partially fluorinated alkyl group, then there must be sufficient fluorination to make the ring-opened form of the hydroxyl (-OH) acidic so that the hydroxyl protons are substantially removed in an alkaline medium, such as aqueous sodium hydroxide or tetraalkylammonium hydroxide. In general, the fluorinated alkyl group of the fluoroalcohol functional group in the ring-opened form should have a sufficient degree of fluorine substitution to give the hydroxyl group the pKa value as follows: pKa is more than 5 and less than 11.

R_fAnd R_f' preferably independently a perfluoroalkyl group of 1 to about 5 carbon atoms, most preferably R_fAnd R_f' both are trifluoromethyl (CF)₃). For protected materials containing protecting groups of formula II, it is preferred that p is 0 or 1 and R is hydrogen.

When the material to be protected is a polymeric binder, it may also be prepared from ethylenically unsaturated monomers using free radical polymerization or metal catalyzed vinyl addition polymerization methods known in the art to provide polymers having repeat units derived from ethylenically unsaturated monomers. Specifically, an ethylenically unsaturated compound having the following structure is subjected to radical polymerization:

a polymer having the following repeating units was obtained:

wherein P, Q, S and T may independently be the same or different and may be, for example, fluorine, hydrogen, chlorine and trifluoromethyl.

If only one ethylenically unsaturated compound is polymerized, the resulting polymer is a homopolymer. If two or more different ethylenically unsaturated compounds are polymerized, the polymer formed is a copolymer.

Some representative examples of ethylenically unsaturated compounds and their corresponding repeating units are illustrated below:

for metal catalyzed vinyl addition polymerizations, one suitable catalyst is a nickel-containing complex. Neutral Ni catalysts are described in WO 9830609. Other references to neutral nickel catalysts based on salicylaldiamino include WO patent application 9842664. Wang, c.; friedrich, s.; younkin, t.r.; li, r.t.; grubbs, r.h.; bansleben, d.a.; day, m.w. organometallics 1998, 17(15), 314 and Younkin, t.; connor, e.g.; henderson, j.i.; friedrich, s.k.; grubbs, r.h.; bansleben, d.a. science 2000, 287, 460-:

ittel, s.d.; johnson, l.k.; brookhart, m.chem.rev.2000, 100, 1169-; novak, b.m.chem.rev.2000, 100, 1479-1493 Moody, l.s.; MacKenzie, p.b.; killian, c.m.; lavoie, g.g.; ponasik, j.a.; barrett, a.g.m.; smith, t.w.; pearson, j.c. wo 0050470 discloses a number of improvements or modifications to the existing ligands and new ligands for recent metal catalysts, for example ligands derived from pyrrole amines rather than anilines, and ligands based on anilines bearing 2, 6-ortho substituents, where these ortho substituents are both aryl or any aromatic group. Specific examples are nickel catalysts based on alpha-diamines derived from pyrroleamine and ortho aryl substituted anilines and nickel catalysts based on salicylaldiamines. Some of these derivatives exhibit improved lifetime/activity/yield/hydrogen response/potential functional group tolerance, etc. Another catalyst which can be used is a novel catalyst which is tolerant to functional groups and is usually based on Ni (II) or Pd (II). Useful catalysts are disclosed in WO 98/56837 and US 5,677,405.

Any suitable polymerization conditions may be used in the process for preparing the polymer. Generally, when metal catalyzed vinyl addition polymerization is employed, the temperature is maintained below about 80 deg.C, typically at 20-80 deg.C. Known suitable solvents, such as trichlorobenzene or p-xylene, may be used.

The binder polymer used in the photoresist composition is preferably highly transparent at the wavelengths of light used to produce the photoimage. Preferably, the absorption coefficient of the adhesive at this wavelength is less than 4.0 μm^-1More preferably less than 3.5 μm^-1Preferably less than 2.5 μm^-1. As shown in one embodiment, the adhesive polymer with fluorinated cyclic ether groups can have high transparency at 157nm, making these compositions particularly useful at this wavelength.

Some illustrative, but non-limiting, examples of fluorinated cyclic ether group-containing comonomers within the scope of the present invention are listed below:

the fluorochemical adhesive polymers of the present invention may optionally contain additional protected fluoroalcohol functional groups. Some illustrative, non-limiting examples of typical comonomers containing a protected fluoroalcohol functional group are illustrated below:

CH₂＝CHO(CH₂)₂OCH₂C(CF₃)₂OCH₂OCH₃

such fluoropolymers may be photoactive polymers, i.e., the photoactive component may be chemically bonded to the fluoropolymer. This can be achieved by chemically bonding the photoactive component to one monomer, followed by copolymerization of the monomer, thereby eliminating the need for a separate photoactive component.

The fluoropolymer of the present invention may comprise repeating units derived from at least one ethylenically unsaturated compound, characterized in that at least one ethylenically unsaturated compound is polycyclic and at least one ethylenically unsaturated compound contains at least one fluorine atom covalently bonded to one ethylenically unsaturated carbon atom.

One or more additional monomers may be used in the preparation of the fluoropolymer, and in general, it is believed that acrylate monomers may be suitable as additional monomers for preparing the polymer. Typical additional monomers include acrylates, olefins containing electron withdrawing groups (non-fluorine) directly attached to the double bond. These terpolymers can be made by free radical polymerization of, for example, acrylonitrile, vinyl chloride, 1-difluoroethylene. Vinyl acetate may also be used as an additional monomer.

Alternatively, the fluoropolymer may contain a spacer group.

The spacer group is a hydrocarbon compound containing vinyl unsaturation and may optionally contain at least one heteroatom, such as an oxygen or nitrogen atom. The hydrocarbon compounds considered as spacers generally contain from 2 to 10, more generally from 2 to 6, carbon atoms. The hydrocarbon may be straight chain or branched. Specific examples of suitable spacers are selected from ethylene, alpha-olefins, 1' -disubstituted olefins, vinyl alcohols, vinyl ethers and 1, 3-dienes. Typically, when the spacer is an alpha-olefin, it is selected from the group consisting of ethylene, propylene, 1-butene, 1-pentene, 1-hexene and 1-octene. Typically, when the spacer is a vinyl ether, it is selected from methyl vinyl ether and ethyl vinyl ether. Typical vinyl alcohols are obtained by hydrolysis after polymerization using functional groups already incorporated in the polymer backbone, for example the acetate group of vinyl acetate. When the spacer is a 1, 3-diene, it is typically butadiene. When the spacer is a 1, 1' -disubstituted alkene, it is typically isobutylene or isoamylene.

The ratio of spacer-containing monomer to other monomers can be important. Typical ranges for these are about 30-70%. Alternatively, a spacer group selected from ethylene, alpha-olefins, 1-disubstituted olefins, vinyl alcohols, vinyl ethers, and 1, 3-dienes may be present in the polymer. Other types of polymers, such as methacrylates and acrylates, can also be used.

The amount of polymeric binder in the photoresist composition can be about 50 to 99.5% of the total weight of the photoresist composition (solids).

Photoactive component (PAC)

The photoresist composition contains a binder in combination with a photoactive component.

If the binder polymer itself is photoactive, then no additional photoactive component is required. The photoactive component may be chemically bonded to the polymer of the binder. EP 473547 describes systems in which the polymer binder itself is photochemically active. The photoresists of this patent contain an ethylenically unsaturated sulfonium or iodonium salt (photoactive component) copolymerized with an ethylenically unsaturated comonomer containing an acid sensitive group to form a radiation sensitive copolymer which is an effective photoactive polymer binder.

When the compositions of the present invention contain a single photoactive component (PAC), the binder itself is generally not photoactive.

The photoactive component (PAC) is typically a compound that generates an acid or base when subjected to actinic radiation. If an acid is generated upon exposure to actinic radiation, the PAC is referred to as a photoacid generator (PAG). If the base is generated upon exposure to actinic radiation, the PAC is referred to as a photobase generator (PBG).

Suitable photoacid generators of the present invention include, but are not limited to: 1) sulfonium salts (structure IV), 2) iodonium salts (structure V), and 3) hydroxamates, such as structure VI.

In the structural formulae IV-V, R₁-R₃Independently is a substituted or unsubstituted aryl group or is a substituted or unsubstituted C₁-C₂₀Alkaryl (aralkyl). Typical aryl groups include, but are not limited to, phenyl and naphthyl. Suitable substituents include, but are not limited to, hydroxy (-OH) and C₁-C₂₀Alkoxy (e.g. C)₁₀H₂₁O). Anion X in structures IV-V^-May be but is not limited to SbF₆ ^-(hexafluoroantimonate), CF₃SO₃ ^-(trifluoromethanesulfonic acid group) and C₄F₉SO₃ ^-(perfluorobutanesulfonic acid group).

Dissolution inhibitors

When the protected material of the present invention is a dissolution inhibitor, it includes those compounds whose absorption coefficient at the imaging wavelength has been found to be low enough for use in microlithographic exposure. In particular, the compounds of the present invention have an absorption coefficient of less than about 4.0 μm at 157nm^-1Typically less than about 3.5 μm at a wavelength of 157nm^-1More typically less than about 3.0 μm at 157nm^-1Especially an absorption coefficient of less than about 2.5 μm at 157nm^-1. The dissolution inhibitors can meet a variety of functional needs, including dissolution inhibition, plasma etch resistance, plasticization, and adhesion properties of the photoresist composition.

The substance to be protected may be a dissolution inhibitor. The dissolution inhibitor typically comprises an alkane, cycloalkane or oligomeric compound. The dissolution inhibitor may have the same monomeric composition as the binder in its structure, but generally has a lower molecular weight than the binder polymer. For example, the dissolution inhibitor may contain at least one functional group as described above of the following structure:

-C(R_f)(R_f′)OR₃

the dissolution inhibitor may also contain a cyclic ester which can be opened by the action of a photoacid in the absence of moisture.

However, when the substance to be protected is a dissolution inhibitor, the polymeric binder may be any polymer having transparent properties suitable for use in fine exposure. Binders suitable for the present invention may include those polymers that are typically incorporated into chemically amplified 248 (deep ultraviolet) and 193nm photoresists for imaging at longer wavelengths. A typical 248nm photoresist adhesive is based on polymers of p-hydroxystyrene. Other examples of suitable 248nm photoresist adhesives can be found in the references introductions to microlithography, 2nd ed.by l.f.thompson, c.g.willson, and m.j.bowden, American chemical society, Washington DC, 1994, chapter 3. Binders useful for 193nm photoresists include cyclic olefin-maleic anhydride alternating copolymers [ such as those mentioned in:

F.M.Houlihan et al.，Macromolecules，30，pages 6517-6534(1997)；T.Wallow et al.，Proc.SPIE，2724，355；and F.M.Houlihan et al.，Journal of Photopolymer Science and Technology，10，511(1997)]polymers of functionalized norbornene-type monomers prepared by metal catalyzed vinyl addition polymerization or ring opening metathesis polymerization [ e.g. as described in u.okoroanyanwu et al j.mol.cat.a: chemical13393(1998) and those mentioned in PCT WO 97/33198]And acrylate copolymers [ polymers mentioned in US 5,372,912]. Photoresist adhesives suitable for use in the present invention also include adhesives that are transparent at wavelengths below 248 and 193nm, such as those containing fluoroalcohol functional groups [ e.g., as in K.J.Pryzbilla et al, Proc.SPIE1672, 9(1992) and H.Ito et al, Polymn Mater.Sci.Eng.77449(1997) to]。

Typical examples of polymers that may also act as dissolution inhibitors are those polymers developed for chemically amplified photoresists imaged at radiation wavelengths of 157 nm. Specific examples of these polymers are fluoropolymers and fluoropolymers containing fluoroalcohol functional groups. Suitable examples are disclosed in WO 00/17712, WO 00/25178, and PCT/US00/11539, filed on 28.4.2000, with the proviso that when the protecting group is a cyclic ether represented by structures I and II, the photoresist composition does not contain acidic groups having a pKa of < 11, typically < 12, more typically < 14, in the unexposed state.

The dissolution inhibitors having a protecting group of the present invention may comprise an alkane or cycloalkane compound having at least one protecting group, typically at least 2, more typically from 2 to about 10, most typically from 2 to 3 cyclic ether protecting groups having the structure I, II or III described above.

Generally, when a compound contains at least 2 protecting groups, the solubility of the dissolution inhibitor in the developed form increases, while the solubility of the undeveloped form is less.

In general, R_fAnd R_f' independently is a perfluoroalkyl group of 1 to about 5 carbon atoms, more typically a perfluoroalkyl group of 1 to about 3 carbon atoms, most typically R_fAnd R_f' both are trifluoromethyl (CF)₃)。

Is represented as R_fAnd R_fThe fluoroalkyl group of' may be a partially fluorinated alkyl group or a perfluorinated alkyl group (e.g., perfluoroalkyl group) as described above.

In a preferred aspect of the invention, the degree of fluorine substitution in the fluorinated alkyl group of the fluoroalcohol functional group is sufficient to provide a hydroxyl group having a pKa value as follows: pKa is more than 5 and less than 11.

One instance of a dissolution inhibitor is an oligomer comprising repeating units derived from at least one ethylenically unsaturated compound containing a protected fluoroalcohol functional group containing one or more cyclic A ether groups or cyclic B ester groups as defined above.

In the present invention, the oligomer is a low molecular weight polymer (e.g., dimer, trimer, tetramer) having an average molecular weight of less than or equal to 3000. As is well known to those skilled in the art, some ethylenically unsaturated compounds (monomers) undergo free radical polymerization or metal catalyzed addition polymerization to form polymers having repeat units derived from the ethylenically unsaturated compounds. By appropriately adjusting the polymerization conditions during the synthesis, in particular using chain transfer agents or chain terminators, the molecular weight of the product can be controlled to the desired range. Chain transfer agents useful for controlling molecular weight in free radical polymerization are well known in the art and include primary and secondary alcohols (e.g., methanol, ethanol, and 2-propanol), chlorocarbons (e.g., carbon tetrachloride), and mercaptans (e.g., dodecyl mercaptan). Transition metal catalyzed addition polymerization of monomers containing cyclic fluorinated ether groups can be utilized. The molecular weight can be reduced by adding a suitable chain transfer agent, such as hydrogen, silane or an olefin (e.g., ethylene, propylene or 1-hexene), to form an oligomer. The control and reduction of molecular weight in the polymerization of norbornene-type monomers catalyzed by nickel and palladium catalysts using olefins is known in the art, see for example US 5,741,869, US 5,571,881, US 5,569,730 and US 5,468,819.

Some illustrative (non-limiting) examples of typical monomers containing fluorinated ether functional groups that fall within the scope of the present invention are listed below:

in another aspect of the invention, the dissolution inhibitor is a compound comprising the structure:

wherein A is an alkanyl or cycloalkyl radical having 2 to 30 carbon atoms, R_fAnd R_f' As above, b is an integer of at least 1, usually at least 2, more usually from 2 to about 10, and most typically from 2 to 3.

By alkanyl or cycloalkyl is understood a radical which contains carbon and hydrogen atoms and is substantially free of olefinic, acetylenic or aromatic unsaturation. The alkyl or cycloalkyl group may contain a heteroatom selected from fluorine, chlorine and oxygen. These heteroatoms may form substituents which do not contribute significantly to the absorption of light at short wavelengths. Specific examples of these oxygen-containing substituents are hydroxyl groups and ethers. For example, one cycloalkyl starter is 4, 4' -isopropylidenedicyclohexanol. Some non-limiting examples of dissolution inhibitors that fall within the scope of this embodiment are listed below:

if the dissolution inhibitor of the present invention contains more than one fluorinated cyclic ether group, R_fAnd R_fThe' groups may be the same or different.

The fluorinated ether groups can be used alone or in combination with one or more other protected acidic groups, such as protected fluoroalcohol or carboxylic acid groups.

Dissolution inhibitors may be prepared by methods known in the art, for example, the bis (trifluoromethyl) oxetanyl-containing materials described above may be prepared by reacting the corresponding divinyl ethers with hexafluoroacetone as described in U.S. Pat. No. 3,164,610(1964) or Izv. Akad. Nauk. Ser Khilm 1967, p.918-921.

Some dissolution-inhibiting compounds also function as plasticizers in the photoresist composition.

A dissolution inhibiting amount of a dissolution inhibitor is combined with the binder and any other photoresist additives. The dissolution inhibitor may be used in an amount of about 0.5 to about 50 percent, more usually about 1 to about 35 percent, and most typically about 5 to about 20 percent, by weight of the total (solids) weight of the photoresist composition.

Other Components

The compositions of the present invention may contain optional additional components. Examples of such additional components include, but are not limited to: resolution enhancers, adhesion promoters, residue reducing agents, coating aids, plasticizers, and Tg (glass transition temperature) modifiers.

Process step

Imagewise exposure

The photoresist composition of the invention is sensitive to the ultraviolet region of the electromagnetic spectrum, especially to the region with the wavelength less than or equal to 365 nm. Imagewise exposure of the photoresist composition of the invention can be carried out at many different UV wavelengths, including but not limited to 365nm, 248nm, 193nm, 157nm and lower. The imagewise exposure is preferably carried out with ultraviolet light of 248nm, 193nm, 157nm or less, preferably 193nm, 157nm or less, most preferably 157nm or less. The imagewise exposure can be carried out digitally with a laser or a corresponding apparatus or non-digitally with a photomask. Preferably digitally imaged with a laser. Laser devices suitable for digital imaging of the compositions of the present invention include, but are not limited to: an Ar-F excimer laser with 193nm UV output, a Kr-F excimer laser with 248nm UV output, and a F2 laser with 157nm output. As noted above, lower wavelengths (e.g., 193nm or 157nm or less) are generally preferred over higher wavelengths (e.g., 248nm or more) because imagewise exposure using lower wavelength UV light corresponds to higher resolution (lower resolution limit).

Development

The polymer in the photoresist composition of the invention must contain sufficient functionality for development after UV imagewise exposure. Typically, the functionality is an acid or a protected acid so that aqueous development can be carried out with an alkaline developer, such as sodium hydroxide solution, potassium hydroxide solution, or ammonium hydroxide solution. The protecting groups of the present invention are advantageous because they do not require moisture to deprotect the developable group and, due to the cyclic nature of the protecting group, do not produce volatile deprotected products.

When an aqueous processable photoresist is coated or applied to a substrate and exposed image-wise to UV light, development of the photoresist composition may require that the binder material contain sufficient protected acidic groups that are at least partially deprotected upon exposure to light so that the photoresist (or other photoimageable coating composition) can be processed in an aqueous alkaline developer. In the case of a positive photoresist layer, the portions of the photoresist layer exposed to UV radiation will be removed during development, while the unexposed portions are substantially unaffected during development with an aqueous alkaline solution, such as an aqueous full solution containing 0.262N tetramethylammonium hydroxide (typically developing for less than or equal to 120 seconds at 25 ℃). In the case of a negative photoresist layer, the portions of the photoresist layer not exposed to UV radiation are removed during development, while the exposed portions are substantially unaffected during development with critical fluids or organic solvents.

A critical fluid as used herein is one or more substances that are heated to near or above their critical temperature and compressed to near or above their critical pressure. The critical fluid of the present invention has a temperature at least 15 ℃ above the critical temperature of the fluid and a pressure at least 5 atmospheres below the critical pressure of the fluid. Carbon dioxide may be used as the critical fluid in the present invention.

Various organic solvents can also be used as the developer of the present invention. This includes, but is not limited to, halogenated solvents and non-halogenated solvents. Halogenated solvents are preferred, fluorinated solvents are more preferred.

Substrate

Examples of substrates used in the present invention are silicon, silicon dioxide, silicon nitride or other materials used in semiconductor manufacturing.

Examples

Example 1：

A compound of the following structure was prepared using the following procedure:

25g of the vinyl ether prepared from exo-5-norbornen-2-ol are dissolved in 100ml of diethyl ether, 0.5g of potassium carbonate are added to the solution, and 32g of hexafluoroacetone (5% excess) are introduced into the reactor in gaseous form at 10-15 ℃. The reaction mixture was heated to 25 ℃ and stirred at this temperature for 1 hour. The solvent was removed in vacuo at 30 ℃ and the crude product was distilled in vacuo to give 34.8g (63%) of product with a purity > 95%,

b.p.50-52℃/0.38mm Hg.

¹H NMR(CDCl₃)：1.3-1.8(4H)，2.7-3.1(4H)，3.8(2H)，5.6(1H)，5.8(1H)，6.1(1H)ppm，¹⁹F NMR(CDCl₃)：-79.13(3F，m)，-79.28(3F，m)PPM.

example 2：

An oxetane a monomer having the following structure was prepared using the following procedure:

22.8g (0.2mol) of CH₂＝CHO(CH₂)₂OCH＝CH₂Dissolved in 100ml of anhydrous ether, 33g (0.2mol) of hexafluoroacetone were introduced into the reactor in gaseous form at-20 ℃. The reaction mixture was maintained at-15 ℃ for 30 minutes, warmed to 25 ℃, the solvent was removed under reduced pressure, and the residue (55g) was taken up in 0.1g K₂CO₃Distillation under reduced pressure in the presence of 26g (46.6%) of a fraction boiling at 43-48 ℃/0.25mmHg (main fraction 45-46 ℃) was obtained, which was found to be the title compound with a purity > 98%. According to NMR data, 25g of residue are predominantly the condensation product of 1 mol of divinyl ether with 2mol of hexafluoroacetone.

¹H NMR (acetone-d)₆)：2.60(1H)，2.8(1H，dd)，3.15(1H，dd)，3.6-4.2(5H)，5.65(1H，t)，6.35(1H，dd)PPM；¹⁹F NMR (acetone-d)₆)：-79.72(3F，m)，-79.83(3F，m)PPM.

Example 3：

A bis (trifluoromethyl) oxetane-containing polymer was synthesized by the following procedure

A200 ml stainless steel autoclave was charged with 15.4g (0.08mol) of adamantane methyl vinyl ether (AdVether), 22.4g (0.08mol) of the oxetane monomer of example 2 (OXVE), 50ml of t-butanol, 25ml of isopropanol, 0.5g of potassium carbonate and 0.4g of Vazo^52. The vessel was closed, cooled, evacuated and flushed with nitrogen several times. 24g (0.24mol) of Tetrafluoroethylene (TFE) were then charged. The autoclave contents were stirred at 50 ℃ for 18 hours, resulting in a pressure change from 294psi to 134 psi. The vessel was cooled to room temperature and evacuated to 1 atmosphere. The contents of the vessel were removed by rinsing with acetone to give a clear pale yellow solution. This solution was slowly added to an excess of ice water, resulting in the formation of a white polymer precipitate, which was dried overnight in a vacuum oven. Yield 49.8g (81%). GPC analysis: mn 35,500, Mw 73300, Mw/Mn 2.06. DSC analysis: a Tg of 35 ℃ was observed on the second heating.¹HNMR (Δ, THF-d8)1.48-20.5(m, 15H from adamantane ring), 2.37-2.80(m, CH from polymer backbone)₂) 2.91(m, H of oxetane ring), 3.15(m, H of oxetane ring), 3.20-3.40(m, CH attached to adamantane ring)₂O), 3.87(m, OCH attached to the oxetane Ring)₂CH₂O), 4.22 and 4.40(m, CH on the polymer backbone), 5,68(m, acetal hydrogens). By integration, the ratio OXVE/AdVether in the polymer was 57: 43.¹⁹F NMR(δ，THF-d8)-78.9(CF₃) From-107 to-125 (CF)₂). According to fluorine NMR, the ratio of OXVE to THF in the polymer was 33: 67. These proportions combined to give an overall composition of 53% TFE, 20% AdVether and 26% OXVE. Analysis of experimental values: c, 46.34; h, 4.43; f, 37.96.

Example 4：

A bis (trifluoromethyl) oxetane-containing polymer was prepared using the following procedure:

into a 200ml stainless steel autoclave were charged 16.0g (0.17mol) of norbornene, 21.1g (0.07mol) of the oxetane-containing monomer (NB-OX) of example 1, 75ml of 1, 1, 2-trichlorotrifluoroethane, 0.5g of potassium carbonate and 1.0g of PerKadox^16. The vessel was closed, cooled, evacuated and purged with nitrogen several times. Then 30g (0.30mol) of Tetrafluoroethylene (TFE) were charged. The autoclave contents were stirred at 50 ℃ for about 18 hours, resulting in a pressure change from 228psi to 201 psi. The vessel was cooled to room temperature and evacuated to 1 atmosphere. The vessel contents were removed by flushing with 1, 1, 2-trichlorotrifluoroethane to give a clear solution. This solution was slowly added to an excess of ethanol, resulting in the formation of a white polymer precipitate, which was dried overnight in a vacuum oven. Yield 17.1g (25%). GPC analysis: mn is 5200; mw 8200; Mw/Mn is 1.57. DSC analysis: a Tg of 111 ℃ was observed on the second heating. The fluorine NMR spectrum showed-76.8 to-78.6 ppm (CF)₃) And-95 to-125 ppm (CF)₂) Confirming that NB-OX and TFE were incorporated in a ratio of 1: 2.8, respectively. The polymer film obtained from the 2-heptanone solution by spin coating had an absorbance at 157nm of 1.33. mu.m^-1Indicating a high degree of optical transparency at this wavelength.

Analysis of experimental values: c, 52.03; h, 4.79; f, 37.22.

Example 5：

Isomerizing an oxetane-containing polymer using the following steps:

6g of the TFE/Adyether/OXVE terpolymer prepared in example 3 were dissolved in 80ml of diethyl ether and 0.1g H was added dropwise over 5 minutes₂SO₄(96%) the reaction mixture was stirred at room temperature for 1 hour, maintaining the temperature of the reaction mixture < 25 ℃. The light yellow solution was filtered through glass wool. According to NMR, the solution does not contain any substances containing oxetane rings.¹The H NMR spectrum showed two doublets at 4.9 and 7.1ppm, typical of the vinyl protons of the CH ═ CH segment (starting fromOf starting materials¹H NMR contained only one signal in this region-6 ppm);¹⁹the F spectrum contained only one signal at-79.0 ppm (two signals in the starting material: -79.01 and-79.2 ppm). The solvent was removed under reduced pressure to leave 5.2g of a pale yellow polymer which was insoluble in diethyl ether, acetone and ethyl acetate. 4.5g of this material were dissolved in 30ml of dimethylacetamide at 60-70 deg.C (4 hours), and the solution was left at ambient temperature for 2 days. The precipitate formed was separated from the liquid, washed with water, filtered, washed with methanol and air-dried at 25 ℃ for 1 hour. 4g of white polymer were isolated. Two new lines at 1633(C ═ C) and 3433(OH) were found in the IR spectrum (KBr) of this material, which were not present in the IR spectrum of the starting material.

Example 6：

Preparation of gamma, gamma-dimethyl-alpha-methylene-gamma-butyrolactone (g, g-dimethyl MBL or DM-MBL)

Example 6a: preparation of triisopropylbenzenesulfonyl hydrazide

A500 ml three-necked flask equipped with a mechanical stirrer, thermometer, addition funnel and condenser with nitrogen tee was charged with 2, 4, 6-triisopropylbenzenesulfonyl chloride (100g, 0.33mol) and THF (120ml) and cooled to 10 ℃. Hydrazine monohydrate (36g, 0.73mol) was added dropwise over 20 minutes via an addition funnel (exothermic reaction) while maintaining the temperature at 10-15 ℃. The reaction mixture turned into a yellow slurry, then into a cloudy solution, and then into a yellow slurry. After the addition, a precipitate formed. 80ml of THF were added and the solid dissolved to form a yellow solution. The mixture was stirred for 30 minutes. Two layers can be seen to form. The organic layer (top layer) was washed with 100ml of saturated NaCl solution and MgSO₄Dried, filtered and evaporated on a rotary evaporator to give a pale yellow solid. The solid was triturated with petroleum ether, filtered and washed with 300ml of petroleum ether. The solid was dried under a stream of nitrogen overnight to give the desired product (88g, 98.7g theory) as a white solidAnd (3) a body. The filtrate was concentrated and triturated with petroleum ether to give an additional 4g of the desired product.

¹H NMR(500MHz，CDCl3)δ1.2(s，18H)，3.0(m，1H)，3.5(br s，2H)，4.0(m，2H)，5.5(br s，1H)，7.3(d，2H)；13C NMR(125 MHz，CDCl3)δ23.30，24.68，29.50，34.02，123.82，128.50，151.64，153.63.

Example 6b: preparation of acetone 2, 4, 6-triisopropylbenzenesulfonyl hydrazide

A500 ml three-necked flask equipped with a mechanical stirrer, thermometer, addition funnel and condenser with nitrogen tee was charged with 300ml of acetone and 2, 4, 6-triisopropylbenzenesulfonylhydrazide (87.9g, 0.29mol) was added under stirring. Note that: the temperature increased from 20 ℃ to 30 ℃ when the body was fixed. 1ml of concentrated hydrochloric acid was added and the cloudy solution was stirred for 1 hour. The desired product (solid) precipitated during the reaction. The mixture was filtered and the solid washed with water (2X 200ml) and dried under nitrogen purge to give 30.7g of the desired product. The filtrate was slowly poured into cooled 300ml water to form a white slurry. The slurry was stirred for 15 minutes, filtered, washed with 250ml of water and dried under a stream of nitrogen to give 64.2g of the desired product as a white solid. And (4) merging yield: 64.2g +30.7 g-94.9 g (96%).

1H NMR(500MHz，CDCl3)δ1.75(s，18H)，1.9(s，3H)，1.95(s，3H)，2.5(m，1H)，4.1(m，2H)，7.2(s，2H)；13C NMR(125MHz，CDCl3)δ16.37，23.46，24.70，24.84，25.25，29.83，34.05，123.68，131.42，151.29，153.00，154.06.

Example 6c: preparation of g, g-dimethyl-MBL (DM-MBL)

A2000 ml three-necked flask equipped with a mechanical stirrer, thermometer, addition funnel and condenser with nitrogen tee was charged with 250ml of dimethoxyethane, acetone 2, 4, 6-triisopropylmethylsulfonylhydrazone (45g, 0.133mol), and cooled to-78 ℃ in a dry ice/acetone bath. 2.4 equivalents of n-butyllithium/hexane (20.4g, 0.32mol, 128ml) were added thereto under nitrogen via an addition funnel. The reaction mixture turned from clear to orange to yellow/orange. The temperature was allowed to rise to-50 ℃ over 10 minutes. Acetone (13.7g, 0.236mol, 1.77 eq.) was added dropwise thereto via syringe and maintained at a temperature of-50 ℃ (exothermic reaction with acetone). The reaction mixture turned orange/yellow to almost clear upon addition of acetone. The reaction mixture was cooled to-78 ℃ and then 1.8 equivalents of n-butyllithium (15.3g, 0.24mol, 96ml) were added dropwise. The reaction mixture turned from almost clear to yellow/orange and back to red/orange. It was stirred at-78 ℃ for 8 minutes and then warmed to-5 ℃ over 45 minutes. This was followed by holding at-5 ℃ for 1 hour, then cooling back to-78 ℃ (dry ice/acetone), bubbling CO2 gas for 10 minutes (slowly bubbling uniformly, taking care of the exothermic reaction) to stop the reaction. The reaction mixture was warmed to room temperature and stopped with 400ml of cold water (cautiously, added dropwise). To this mixture was added 200ml EtOAc and the reaction mixture was filtered through a celite bed washing the celite with 200ml EtOAc. The layers were separated and the aqueous layer was acidified to pH 1 with trifluoroacetic acid (74g) and stirred overnight. During this time a small amount of solid precipitated. The aqueous layer was extracted with EtOAc (3X 100ml) and the combined organic layers were washed with 100ml saturated NaCl, MgSO₄Dried and concentrated under reduced pressure to give 90g of a crude yellow oil. The oil was purified by column chromatography: silica gel, 1/4 EtOAc/hexanes (R)_f0.4) to yield 15.4g (92%) of the desired product as a light orange oil (purity 87% by GC). The product is further purified by vacuum distillation to obtain the desired product in colorless liquid state; BP 50-53 deg.C/0.4 mmHg;

¹H NMR(500MHz，CDCl3)δ1.35(s，6H)，2.7(m，2H)，5.55(m，1H)，6.15(m，1H)；13C NMR(125MHz，CDCl3)δ28.63，41.43，82.26，122.62，136.32，170.46；

(GC purity 97.8%).

Example 7：

Methyl Methacrylate (MMA)/methacrylic acid (MAA)/dimethyl Pseudobulbus Cremastrae Seu pleiones lactone (DMMBL) (42.1/16.85/41.08 w/w) copolymer was prepared by adding the following ingredients to a 100ml flask equipped with a thermocouple, stirrer, dropping funnel, reflux condenser and nitrogen drum.

Parts by weight Keke (Chinese character of 'Keke')

Part 1

Methyl Methacrylate (MMA) 0.8

Methacrylic acid (MAA) 0.32

Dimethyltulip lactone (DMMBL) 0.78

Methyl Ethyl Ketone (MEK) 10.00

Section 2

MEK 2.0

2, 2-azobis (2, 4-dimethylvaleronitrile): vazo^-52 0.08

Section 3

MEK 16.0

2, 2-azobis (2, 4-dimethylvaleronitrile): vazo^-52 0.96

Section 4

Methyl Methacrylate (MMA) 7.20

Methacrylic acid (MAA) 2.88

Dimethyl Pseudobulbus Cremastrae Seu pleiones lactone (DMMBL) 7.03

48.05 in total

The monomer in part 1 was dissolved in 10g of methyl ethyl ketone in a reaction flask. The solution in the reaction flask was purged with nitrogen while heating with a heating mantle to reach the solution reflux temperature. Vazo of fraction 2^-52 dissolved in 2g of methyl ethyl ketone in a vessel and added to the above-mentioned reaction flask. Then part 3 of the Vazo is brought to reflux temperature^-52 initiator solution and part 4 of the monomer mixture were added to the reaction flask at a constant rate over 6 hours and 4 hours, respectively. After the initiator addition was complete, polymerization was continued for a further 1 hour at reflux temperature. Finally the polymer solution was added to a large excess of petroleum ether (500g) to precipitate the polymer and filtered. The polymer was washed 2 times with a small amount of petroleum ether, filtered, and dried overnight in a vacuum oven at 25-30 ℃. The polymer yield was 13.58g (71.5%).

Example 8：

The following solutions were prepared and magnetically stirred through the solution.

Components Weight (gram)

MMA/MAA/DM-MBL copolymer 1.149 as described in example 7

(weight ratio: 42.1/16.9/41.0)

Cyclohexanone 7.803

Lithocholic acid tert-butyl ester 0.300

6.82% 0.748% of triphenylsulfonium nonafluorobutanesulfonate in Cyclohexanone

(by weight) solution, which has been injected with 0.45. mu. PTFE

Filtering by a filter.

Spin coating was performed on 4 inch diameter P-type, <100> oriented silicon wafers using a Brewer Science inc.100cb combined spin coater/hot plate. Development was carried out by hand immersion in a pan.

The silicon wafer was prepared by depositing 6ml of Hexamethyldisilazane (HMDS) primer and spinning at 5000rpm for 10 seconds, then placing about 3ml or more of the solution filtered through a 0.45 μm PTFE syringe filter, spinning at 3000rpm for 60 seconds, and baking at 120 ℃ for 60 seconds.

To achieve 248nm imaging, the coated wafer was exposed to broadband UV light from a Solar Simulator (1000 Watts) of ORIEL 82421 type through a 248nm interference filter that transmitted approximately 30% of the energy at 248 nm. The exposure time was 30 seconds and the unattenuated radiation dose was 20.5mJ/cm². A wide variety of exposure doses are produced by using reticles with 18 different neutral optical density sites. After exposure, the exposed silicon wafer was baked at 120 ℃ for 120 seconds.

The wafer was developed in an aqueous tetramethylammonium hydroxide (TMAH) solution (OKA NMD-3, 1.19% TMAH solution) for 30 seconds to give a positive image.

Claims (25)

1. A photoresist composition comprising:

(a) a protected material comprising a protecting group which is:

A. a cyclic ether group having structure I or II:

wherein R is_fAnd R_f' are identical or different fluoroalkyl groups having from 1 to about 10 carbon atoms, or together are (CF)₂)_aWherein a is an integer from 2 to about 10, R independently represents a hydrogen atom or a straight or branched alkyl group of 1 to about 10 carbon atoms, and P is an integer from 0 to about 8; wherein the protected material is substantially free of acidic groups having a pKa < 11; and

B. a cyclic ester having structure III:

wherein R is₁And R₂Independently represents a substituted or unsubstituted straight or branched alkyl, aryl, aralkyl or alkaryl group, n is an integer from 1 to about 4; and

(b) a photoactive component.

2. The photoresist composition of claim 1, wherein the cyclic ether protecting group has the structure:

wherein R is_fAnd R_f' are identical or different fluoroalkyl groups having from 1 to about 10 carbon atoms, or together are (CF)₂)_aWherein a is an integer from 2 to about 10, R independently represents a hydrogen atom or a straight or branched alkyl group of 1 to about 10 carbon atoms, and P is an integer from 0 to about 8.

3. The photoresist composition of claim 2, wherein R_fAnd R_f' perfluoroalkyl groups of 1 to 5 carbon atoms each, P is 0, and R is a hydrogen atom.

4. The photoresist composition of claim 3, wherein R_fAnd R_f' are both CF₃。

5. The photoresist composition of claim 1 where in cyclic ester group B, n is 1, R₁And R₂Are all CH₃And at least one with the substance to be protectedThe point of attachment being through a saturated ring carbon atom, R₁Or R₂。

6. The photoresist composition of claim 1 wherein the protected material is a polymeric binder.

7. The photoresist composition of claim 6 wherein the polymeric binder has an absorption coefficient of less than about 40 μm at a wavelength of about 157nm^-1。

8. The photoresist composition of claim 6, where the cyclic ester group B is incorporated by copolymerization with gamma, gamma-dimethyl-alpha-methylene-gamma-butyrolactone.

9. The photoresist composition of claim 1 wherein the protected material is a dissolution inhibitor.

10. The photoresist composition of claim 9 wherein the dissolution inhibitor comprises an alkane, cycloalkane or oligomeric compound containing at least one cyclic ether protecting group a of structure I or II

Wherein R is_fAnd R_f' independently represent fluoroalkyl groups of from 1 to about 10 carbon atoms, or taken together are (CF)₂)_aWherein a is an integer from 2 to about 10, R independently represents a hydrogen atom or a straight or branched chain alkyl group of 1 to about 10 carbon atoms, and P is an integer from 0 to about 8, wherein the protected material is substantially free of acidic groups having a pKa < 11.

11. The photoresist composition of claim 9 wherein the dissolution inhibitor comprises an alkane, cycloalkane or oligomeric compound containing at least one cyclic ester protecting group of structure III

Wherein R is₁And R₂Independently represent an unsubstituted straight or branched alkyl group having 1 to 10 carbon atoms; aryl, aralkyl or alkaryl having from 6 to 14 carbon atoms; or substituted groups thereof containing at least one O, S, N, P or halogen atom; n is an integer from 1 to about 4.

12. The photoresist composition of claim 9 wherein the dissolution inhibitor has an absorption of less than about 4.0 μm at a wavelength of about 157nm^-1。

13. A method of preparing a photoresist image on a substrate, comprising, in order:

(W) forming a photoresist layer on the substrate, the photoresist layer being prepared from a photoresist composition comprising:

(a) a protected material comprising a protecting group which is:

A. a cyclic ether group of structure I or II:

wherein R is_fAnd R_f' are fluoroalkyl groups of 1 to about 10 carbon atoms which are the same or different, or together are (CF)₂)_aWherein a is an integer from 2 to about 10, R independently represents a hydrogen atom or a straight or branched alkyl group of 1 to about 10 carbon atoms, and P is an integer from 0 to about 8; wherein the protected material is substantially free of acidic groups having a pKa < 11; and

B. a cyclic ester of structure III:

wherein R is₁And R₂Independently represent an unsubstituted straight or branched alkyl group having 1 to 10 carbon atoms; aryl, aralkyl or alkaryl of 6 to 14 carbon atoms; or a substituted group thereof containing at least one O, S, N, P or halogen atom; n is from 1 toAn integer of about 4; and

(b) an optically active component;

(X) imagewise exposing the photoresist layer to form imaged regions and unimaged regions; and

(Z) developing the exposed photoresist layer with imaged areas and non-imaged areas to form a relief image on the substrate.

14. The process of claim 13, wherein the protecting group comprises a cyclic ether group of the structure:

wherein R is_fAnd R_f' are fluoroalkyl groups of 1 to about 10 carbon atoms which are the same or different, or together are (CF)₂)_aWherein a is an integer from 2 to about 10, R independently represents a hydrogen atom or a straight or branched alkyl group of 1 to about 10 carbon atoms, and P is an integer from 0 to about 8.

15. The process of claim 13, wherein the protecting group is a cyclic ester group of structure III:

wherein R is₁And R₂Independently represent an unsubstituted straight or branched alkyl group having 1 to 10 carbon atoms; aryl, aralkyl or alkaryl of 6 to 14 carbon atoms; or a substituted group thereof containing at least one O, S, N, P or halogen atom; n is an integer from 1 to about 4.

16. The method of claim 13 wherein the substance to be protected is a polymeric binder.

17. The method of claim 16 wherein the polymeric binder has an absorption at about 157nm of less than about 4.0 μm^-1。

18. The process of claim 15 wherein cyclic ester group B is derived by polymerization with γ, γ -dimethyl- α -methylene- γ -butyrolactone.

19. The method of claim 13 wherein the substance to be protected is a dissolution inhibitor.

20. The method of claim 19, wherein the dissolution inhibitor comprises an alkane, cycloalkane, or oligomeric compound containing at least one cyclic ether functional group of the structure:

wherein R is_fAnd R_f' are fluoroalkyl groups of 1 to about 10 carbon atoms which are the same or different, or together are (CF)₂)_aWherein a is an integer from 2 to about 10, R independently represents a hydrogen atom or a straight or branched alkyl group of 1 to about 10 carbon atoms, and P is an integer from 0 to about 8.

21. The method of claim 20, wherein the substance to be protected is a dissolution inhibitor comprising an alkane, cycloalkane or oligomer compound containing at least one cyclic ester functional group of the structure:

wherein R is₁And R₂Independently represent an unsubstituted straight or branched alkyl group having 1 to 10 carbon atoms; aryl, aralkyl or alkaryl of 6 to 14 carbon atoms; or a substituted group thereof containing at least one O, S, N, P or halogen atom; n is an integer from 1 to about 4.

22. The method of claim 20, wherein the dissolution inhibitor has an absorption at about 157nm of less than about 4.0 μm^-1。

23. The photoresist composition of claim 1 wherein at least one point of attachment to the protected material within structure III is through a saturated ring carbon atom, R₁Or R₂。

24. The photoresist composition of claim 1, further comprising a solvent.

25. The method of claim 13 wherein at least one point of attachment to the protected material within structure III is through a saturated ring carbon atom, R₁Or R₂。