KR20040039008A - Fluorine-containing photosensitive polymer and chemically amplified resist composition comprising the same - Google Patents

Abstract

PURPOSE: A photosensitive polymer containing fluorine and a chemically amplified resist composition containing the polymer are provided, to improve a transparency at a wavelength of ArF (193 nm) and F2 (157 nm) excimer lasers and a dry etching resistance. CONSTITUTION: The photosensitive polymer is obtained by the copolymerization of a copolymer represented by the formula 1 and a comonomer having an acid-labile substituent or a polar functional group, wherein R1 is a fluorinated alkyl group of C2-C14 and m/(m+n) is 0.1-0.4. Preferably the polymer has a weight average molecular weight of 3,000-50,000. Preferably the comonomer comprises at least one repeating unit selected from the group consisting of an acrylate derivative, a methacrylate derivative, a norbornene derivative and a styrene derivative. The composition comprises the photosensitive polymer; a photoacid generator; and an organic base.

Description

Fluorine-containing photosensitive polymer and chemically amplified resist composition comprising the same

FIELD OF THE INVENTION The present invention relates to photosensitive polymers and chemically amplified resist compositions, in particular for photosensitive polymers which are usable for ArF (193 nm) and F ₂ (157 nm) excimer lasers and which consist of a cyclic backbone with substituents containing fluorine; It relates to a chemically amplified resist composition comprising the same.

As the semiconductor manufacturing process becomes complicated and the degree of integration of semiconductor devices increases, fine pattern formation is required. Furthermore, in devices with a semiconductor device having a capacity of 1 gigabit or more, a pattern size of 0.1 μm or less is required, and thus there is a limit to using a resist material using a conventional KrF excimer laser (248 nm). have. Therefore, a lithography technique using ArF excimer laser (193 nm) or F ₂ (157 nm) excimer laser, which is a shorter wavelength energy source than KrF excimer laser, has appeared and was developed. In particular, a lithography process using an F ₂ (157 nm) excimer laser requires a resist material having a new structure.

On the other hand, resist materials used in lithography techniques must satisfy the following basic properties. First, the resist film must have high transmittance in the light source. Second, the etching resistance to the plasma used in the dry etching process should be good. Third, in order to prevent the pattern from collapsing, the adhesion property to the underlying film should be good. Fourth, development should be possible with a developer that is commonly used.

There are many limitations to satisfy such material properties. In particular, the permeability of polymer materials and resistance to dry etching have been pointed out as the biggest problems.

To date, several materials have been known as resist materials for next generation F ₂ excimer lasers, mainly fluorinated polymers and siloxane polymers. In particular, the fluorinated polymer has been excellently studied as a next-generation resist material because of its excellent transmittance at 157 nm. However, this material has difficulty in synthesizing monomers and its hydrophobicity is so strong in polymer properties that it is difficult to find a suitable structure as a resist material.

A polynorbornene-type copolymer having a structure shown below as one of the early 157 nm resist materials according to the prior art has been published.

The structure has an advantageous structure in terms of adhesion properties and dry etching resistance of the polymer. However, in polymer synthesis, it is difficult to control the molecular weight and has a disadvantage in that it is difficult to remove impurities caused by the metal catalyst used.

As a resist material according to another prior art, a copolymer of an α-trifluoromethylacrylate monomer and a styrene derivative having the following structure has been disclosed.

This structure is an improved structure of IBM's KrF resist, which has revealed that the fluorinated aromatic compound can function as a thin film resist at 157 nm. However, the above structure still has various problems, and in particular, the resist film's permeability and resistance to dry etching are still subjects to be solved.

An object of the present invention is to improve the disadvantages of the conventional resist material described above, and has excellent transmittance characteristics in ArF (193 nm) and F ₂ (157 nm) excimer laser, which is the next generation energy exposure source, and excellent resistance to dry etching. It is to provide a photosensitive polymer having a structure that can be provided.

Another object of the present invention is to be exposed to ArF (193nm) and F ₂ (157nm) excimer laser which is the next generation energy exposure source, to improve the resistance to dry etching, has a high resolution, the development using a general developer It is to provide a resist composition which can be made.

In order to achieve the above object, the photosensitive polymer according to the present invention (a) a copolymer represented by the following formula,

Wherein R ₁ is a C ₂ to C ₁₄ fluorinated alkyl group, m / (m + n) = 0.1 to 0.4.

(b) a comonomer having an acid-labile substituent or a polar functional group is copolymerized.

The photosensitive polymer according to the present invention has a weight average molecular weight of 3,000 to 50,000.

Preferably, R ₁ is a 2,2,3,3,3-pentafluoro- _1- propaneyl group.

In the photosensitive polymer according to the present invention, the comonomer may be composed of at least one repeating unit selected from the group consisting of acrylate derivatives, methacrylate derivatives, norbornene derivatives and styrene derivatives.

Preferably, the comonomer consists of acrylate or methacrylate derivatives. At this time, the photosensitive polymer has the following structure.

Wherein, R ₂ is a hydrogen atom, a methyl group, or trifluoromethyl, R ₃ is a hydrocarbon of resolvable C ₃ ~ C ₁₄ by an acid group, l / (l + m + n) = 0.1 ~ 0.4, m / (l + m + n) = 0.2-0.5, and n / (l + m + n) = 0.2-0.5. Preferably, R ₃ is a t-butyl group, tetrahydropyranyl group, or 1-ethoxyethyl group. Also preferably, R ₃ is 2-methyl-2-adamantyl group, 2-ethyl-2-adamantyl group, 2-propyl-2-adamantyl group, 2-methyl-2-norbornyl group, 2 -Ethyl-2-norbornyl group, 2-methyl-2-isobornyl group, 2-ethyl-2-isobornyl group, 8-methyl-8-tricyclodecyl group, or 8-ethyl-8-tricyclode It is a practical skill.

Also preferably, the comonomer consists of norbornene derivatives. At this time, the photosensitive polymer has the following structure.

Wherein R ₄ is a hydrogen atom, a hydroxyl group, a halogen group, an alkyl group, a fluorinated alkyl group, an alkoxy group, an aldehyde group, an ester group, a nitrile group, a sulfonated group, and l / (l + m + n) = 0.1 to 0.4, m / (l + m + n) = 0.2 to 0.5, and n / (l + m + n) = 0.2 to 0.5. Preferably, R ₄ is an acid-labile ester group decomposable with an acid of C ₅ to C ₁₄ or a fluorinated alcohol group of C ₃ to C ₁₀ .

Especially preferably, R ₄ is a t-butyl ester group, tetrahydropyranyl ester group, or 1-ethoxyethyl ester group. Alternatively, R ₄ is a 2-methyl-2-adamantyl ester group, 2-ethyl-2-adamantyl ester group, 2-propyl-2-adamantyl ester group, 2-methyl-2-norbor Neyl ester group, 2-ethyl-2-norbornyl ester group, 2-methyl-2-isobornyl ester group, 2-ethyl-2-isobornyl ester group, 8-methyl-8-tricyclodecyl ester Group, or an 8-ethyl-8-tricyclodecyl ester group. Alternatively, R ₄ may be a 2-trifluoromethyl-1,1,1-trifluoro-2-hydroxypropyl group.

The photosensitive polymer according to the present invention may further include a repeating unit made of a styrene derivative represented by the following formula.

Wherein R ₅ is a hydrogen atom, a hydroxy group, a halogen group, an alkyl group, a fluorinated alkyl group, an alkoxy group, an aldehyde group, an ester group, a nitrile group, a sulfonated group, and l / (l + m + n + o) = 0.1 to 0.4, m / (l + m + n + o) = 0.2 to 0.5, n / (l + m + n + o) = 0.2 to 0.5, o / (l + m + n + o) = 0.2-0.5. Preferably, R ₅ is a 2-hydroxyhexafluoroisopropyl group.

In order to achieve the above another object, the resist composition according to the present invention comprises a photosensitive polymer having any one of the structures defined above, a photoacid generator (PAG), and an organic base.

Preferably, the PAG is included in an amount of 1.0 to 15% by weight based on the weight of the photosensitive polymer. Also preferably, the PAG consists of triarylsulfonium salts, diaryliodonium salts or mixtures thereof. For example, the PAG may be composed of triphenylsulfonium triflate, diphenyliodonium triflate, di-t-butylphenyliodonium triflate, or a mixture thereof.

Also preferably, the organic base is included in an amount of 0.01 to 2.0% by weight based on the weight of the photosensitive polymer. The organic base may consist of an organic tertiary amine. For example, the organic base consists of triethylamine, triisobutylamine, triisooctylamine, diethanolamine, triethanolamine or mixtures thereof.

The photosensitive polymer according to the present invention comprises a copolymer of a monomer unit composed of a cyclic backbone with fluorinated alkyl substituents and maleic anhydride. The resist composition obtained from the photosensitive polymer according to the present invention can provide excellent resistance to dry etching and can provide high transmittance for F ₂ (157 nm) excimer laser. In addition, the resist composition according to the present invention can be developed using a general developer, and has excellent transmittance and resistance to dry etching, thereby forming a fine pattern at high resolution.

Next, preferred embodiments of the present invention will be described in detail.

Example 1

Synthesis of Monomers

2,2,3,3,3-pentafluoro-1-propanol (15 g, 0.1 mol) and triethylamine (11 g) were added to a 500 mL three-neck flask with dry tetrahydrofuran (THF) (200 mL). Then, diallyl malonyl dichloride (10 g, 45 mmol) was slowly dropped from room temperature using a dropping funnel under N ₂ purge.

The reaction was allowed to react at a temperature of about 50 ° C. for about 12 hours, after which excess THF was removed and the reaction was placed in excess water. It was neutralized with an appropriate amount of HCl (hydrochloric acid) and then extracted with diethyl ether.

The extracted organic layer was dried using MgSO ₄ , and then the solvent was blown off using a rotary evaporator, and then a desired product was separated using a vacuum distillation. (Yield 60%)

Example 2

Synthesis of Copolymer

Monomer (4.5 g, 10 mmol) synthesized in Example 1 and maleic anhydride (1 g, 10 mmol) were mixed with azobisisobutyronitrile (AIBN) (70 mg, 2 mol%) with THF (5 g). It was dissolved in and then completely purged with nitrogen gas, and then polymerized at a temperature of about 65 ° C. for 20 hours.

After the polymerization was completed, the reaction was slowly precipitated in excess IPA (isopropyl alcohol) solution, the resulting precipitate was filtered off, and the filtered precipitate was once again dissolved in an appropriate amount of THF and reprecipitated in n-hexane. The precipitate was then dried for about 24 hours in a vacuum oven maintained at 50 ° C. to afford the desired product. (Yield 50%)

At this time, the weight average molecular weight (Mw) of the obtained product was 7,100, and polydispersity (Mw / Mn) was 2.0.

Example 3

Synthesis of Terpolymer

Monomer (4.5g, 10mmol) synthesized in Example 1, t-butyl α-trifluoromethylacrylate (2g, 10mmol), maleic anhydride (2g, 20mmol) and AIBN (0.13g, 2mol%) Together in THF (9 g) and then completely purged with nitrogen gas. Thereafter, polymerization was carried out at a temperature of about 65 ° C. for 20 hours.

After the polymerization was over, the reaction was slowly precipitated in excess IPA (isopropyl alcohol) solution, the resulting precipitate was filtered off, and the filtered precipitate was once again dissolved in an appropriate amount of THF and reprecipitated in n-hexane. The precipitate was then dried for 24 hours in a vacuum oven maintained at 50 ° C. to afford the desired product. (Yield 55%)

At this time, the weight average molecular weight (Mw) of the obtained product was 8,500, and polydispersity (Mw / Mn) was 2.0.

Example 4

Synthesis of Terpolymer

The monomer (10 mmol) synthesized in Example 1, maleic anhydride (30 mmol), and third butyl 5-norbornene-2-carboxylate (20 mmol) were combined with AIBN (2 mol%) to THF (monomer weight ratio of 1). And then polymerized in the same manner as in Example 3 to obtain the desired polymer. (Yield 50%)

At this time, the weight average molecular weight (Mw) of the obtained product was 7,700, and polydispersity (Mw / Mn) was 2.1.

Example 5

Synthesis of Tetrapolymer

Monomer (10 mmol) synthesized in Example 1, maleic anhydride (40 mmol), and 5- (2-trifluoromethyl-1,1,1-trifluoro-2-hydroxypropyl) -2-norbor 10 nol and t-butyl 5-norbornene-2-carboxylate (20 mmol) were dissolved in ATFN (2 mol%) in THF (1 times the monomer weight ratio), followed by the same method as in Example 3. The polymerization was carried out to obtain the desired polymer. (Yield 50%)

At this time, the weight average molecular weight (Mw) of the obtained product was 7,000, and polydispersity (Mw / Mn) was 2.0.

Example 6

Synthesis of Tetrapolymer

Monomer (10 mmol) synthesized in Example 1, maleic anhydride (40 mmol), and 5- (2-trifluoromethyl-1,1,1-trifluoro-2-hydroxypropyl) -2-norbor Nene (10 mmol) and t-butyl methacrylate (20 mmol) were dissolved in THF (1.5 times the monomer weight ratio) together with AIBN (2 mol%), and then polymerized in the same manner as in Example 3 to obtain a desired polymer. (Yield 50%)

At this time, the weight average molecular weight (Mw) of the obtained product was 6,600, and polydispersity (Mw / Mn) was 2.0.

Example 7

Synthesis of Tetrapolymer

Monomer (10 mmol) synthesized in Example 1, maleic anhydride (40 mmol), t-butyl 5-norbornene-2-carboxylate (20 mmol), and 4- (2-hydroxyhexafluoroisopropyl ) Styrene (10 mmol) was dissolved in THF (1.5 times the weight ratio of monomer) with AIBN (2 mol%), and then polymerized in the same manner as in Example 3 to obtain a desired polymer. (Yield 55%)

At this time, the weight average molecular weight (Mw) of the obtained product was 8,100, and polydispersity (Mw / Mn) was 2.0.

Example 8

Preparation of resist composition and pattern forming process

1 g of each polymer synthesized in Examples 3 to 7 was dissolved in propylene glycol methyl ether acetate (PGMEA) (7 g) together with triphenylsulfonium triflate (0.01 g), respectively, a photoacid generator (PAG), and then 2 mg of triisobutylamine, which is an organic base, was completely dissolved in the solution to prepare a resist composition.

The obtained resist composition was coated on a bare Si wafer subjected to HMDS (hexamethyldisilazane) to a thickness of about 0.33 μm, and then subjected to soft bake for about 60 to 90 seconds at a temperature range of about 120 to 140 ° C. Then, it exposed using ArF stepper (0.6NA, (sigma) = 0.75).

Then, a post-exposure bake (PEB) was performed for about 60 to 90 seconds at a temperature range of about 110 to 140 ° C., and then developed for about 60 seconds in a 2.38wt% TMAH (tetramethylammonium hydroxide) solution. As a result, when the exposure dose amount was set to about 11-18 mJ / cm ² , it was confirmed that a clean 180 nm line and space pattern was obtained.

In preparing a resist composition according to the present invention, the PAG is included in an amount of 1.0 to 15% by weight based on the weight of the photosensitive polymer, triarylsulfonium salts, diaryliononium salts (diaryliodonium salts) or mixtures thereof. In addition, the organic base is included in an amount of 0.01 to 2.0% by weight based on the weight of the photosensitive polymer, an organic tertiary amine, for example triethylamine, triisobutylamine, triisooctylamine, diethanolamine , Triethanolamine or mixtures thereof.

In the above pattern forming step, when coating the resist composition on the wafer, the thickness may vary depending on the application, and is coated with a thickness of about 0.2 ~ 0.7㎛. In addition, in the prebaking step, the baking temperature varies according to the type of protecting group, and may be usually performed for about 60 to 90 seconds within a temperature range of 110 to 140 ° C. In the exposure step, the dose amount varies according to the deep-UV light source used, and in the case of an ArF or F ₂ excimer laser, energy of 5 to 100 mJ / cm ² can be used. In the PEB step, the baking temperature varies depending on the type of protecting group, and may be usually performed for about 60 to 90 seconds within a temperature range of 110 to 140 ° C. The development step is usually performed for about 20 to 60 seconds with a 2.38 wt% TMAH (0.26 N) solution.

The photosensitive polymer according to the present invention consists of a copolymer having a cyclic backbone structure with fluorinated alkyl substituents. The photosensitive polymer according to the present invention can be prepared relatively easily by general radical polymerization, and in particular, copolymers of fluorinated monomer units and maleic anhydride monomer units can be used in various forms of terpolymers, tetrapolymers, or more. Copolymers can be easily produced. In particular, the fluorinated monomer units included in the photosensitive polymer according to the invention form a cyclic backbone upon polymerization. Thus, the resist composition obtained from the photosensitive polymer according to the present invention can provide excellent resistance to dry etching. In addition, the photosensitive polymer according to the present invention can easily introduce fluorine atoms into its side chain, thereby providing high transmittance when applied to a photolithography process using an F ₂ (157 nm) excimer laser.

The resist composition according to the present invention can be developed using a general developer, and has excellent transmittance and resistance to dry etching, thereby forming a fine pattern at high resolution. Therefore, it can be very usefully used in manufacturing future next-generation semiconductor devices.

The present invention has been described in detail with reference to preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications can be made by those skilled in the art within the scope of the technical idea of the present invention. Do.

Claims (34)

(a) a copolymer represented by the following formula, Wherein R ₁ is a C ₂ to C ₁₄ fluorinated alkyl group, m / (m + n) = 0.1 to 0.4. (b) A photosensitive polymer comprising copolymerizing a comonomer having an acid-labile substituent or a polar functional group. The method of claim 1, It has a weight average molecular weight of 3,000-50,000, The photosensitive polymer characterized by the above-mentioned. The method of claim 1, R ₁ is a 2,2,3,3,3-pentafluoro-1-propanyl group. The method of claim 1, The comonomer is a photosensitive polymer, characterized in that consisting of at least one repeating unit selected from the group consisting of acrylate derivatives, methacrylate derivatives, norbornene derivatives and styrene derivatives. The method of claim 4, wherein The comonomer is composed of an acrylate or methacrylate derivative, and has a following structure. Wherein, R ₂ is a hydrogen atom, a methyl group, or trifluoromethyl, R ₃ is a hydrocarbon of resolvable C ₃ ~ C ₁₄ by an acid group, l / (l + m + n) = 0.1 ~ 0.4, m / (l + m + n) = 0.2-0.5 and n / (l + m + n) = 0.2-0.5. The method of claim 5, R ₃ is a t-butyl group, tetrahydropyranyl group, or 1-ethoxyethyl group. The method of claim 5, R ₃ is 2-methyl-2-adamantyl group, 2-ethyl-2-adamantyl group, 2-propyl-2-adamantyl group, 2-methyl-2-norbornyl group, 2-ethyl-2- Norbornyl, 2-methyl-2-isobornyl, 2-ethyl-2-isobornyl, 8-methyl-8-tricyclodecyl, or 8-ethyl-8-tricyclodecyl Photosensitive polymer. The method of claim 4, wherein The comonomer is made of a norbornene derivative, and has a structure of the following. Wherein R ₄ is a hydrogen atom, a hydroxyl group, a halogen group, an alkyl group, a fluorinated alkyl group, an alkoxy group, an aldehyde group, an ester group, a nitrile group, a sulfonated group, and l / (l + m + n) = 0.1 to 0.4, m / (l + m + n) = 0.2 to 0.5, and n / (l + m + n) = 0.2 to 0.5. The method of claim 8, R ₄ is an acid-labile ester group decomposable by an acid of C ₅ to C ₁₄ or a fluorinated alcohol group of C ₃ to C ₁₀ . The method of claim 8, R ₄ is a t-butyl ester group, a tetrahydropyranyl ester group, or a 1-ethoxyethyl ester group. The method of claim 8, R ₄ is 2-methyl-2-adamantyl ester group, 2-ethyl-2-adamantyl ester group, 2-propyl-2-adamantyl ester group, 2-methyl-2-norbornyl ester Group, 2-ethyl-2-norbornyl ester group, 2-methyl-2-isobornyl ester group, 2-ethyl-2-isobornyl ester group, 8-methyl-8-tricyclodecyl ester group, Or an 8-ethyl-8-tricyclodecyl ester group. The method of claim 8, R ₄ is a photosensitive polymer, characterized in that the 2-trifluoromethyl-1,1,1-trifluoro-2-hydroxypropyl group. The method of claim 8, The photosensitive polymer characterized by further including the repeating unit which consists of a styrene derivative represented by a following formula. Wherein R ₅ is a hydrogen atom, a hydroxy group, a halogen group, an alkyl group, a fluorinated alkyl group, an alkoxy group, an aldehyde group, an ester group, a nitrile group, a sulfonated group, and l / (l + m + n + o) = 0.1 to 0.4, m / (l + m + n + o) = 0.2 to 0.5, n / (l + m + n + o) = 0.2 to 0.5, o / (l + m + n + o) = 0.2 to 0.5. The method of claim 13, The R ₅ is a photosensitive polymer, characterized in that 2-hydroxyhexafluoroisopropyl group. (a) a copolymer represented by the following formula (a-1), Wherein R ₁ is a C ₂ to C ₁₄ fluorinated alkyl group, m / (m + n) = 0.1 to 0.4. (a-2) a photosensitive polymer formed by copolymerizing a comonomer having an acid-labile substituent or a polar functional group, (b) a photoacid generator (PAG), (c) A resist composition comprising an organic base. The method of claim 15, The photosensitive polymer has a weight average molecular weight of 3,000 to 50,000 characterized in that the resist composition. The method of claim 15, The R ₁ is a resist composition, characterized in that 2,2,3,3,3-pentafluoro-1-propaneyl group. The method of claim 15, The comonomer is a resist composition comprising at least one repeating unit selected from the group consisting of acrylate derivatives, methacrylate derivatives, norbornene derivatives and styrene derivatives. The method of claim 18, The comonomer is composed of an acrylate or methacrylate derivative, and the photosensitive polymer has the following structure. Wherein, R ₂ is a hydrogen atom, a methyl group, or trifluoromethyl, R ₃ is a hydrocarbon of resolvable C ₃ ~ C ₁₄ by an acid group, l / (l + m + n) = 0.1 ~ 0.4, m / (l + m + n) = 0.2-0.5 and n / (l + m + n) = 0.2-0.5. The method of claim 19, The R ₃ is a resist composition, characterized in that t-butyl group, tetrahydropyranyl group, or 1-ethoxyethyl group. The method of claim 19, R ₃ is 2-methyl-2-adamantyl group, 2-ethyl-2-adamantyl group, 2-propyl-2-adamantyl group, 2-methyl-2-norbornyl group, 2-ethyl-2- Norbornyl, 2-methyl-2-isobornyl, 2-ethyl-2-isobornyl, 8-methyl-8-tricyclodecyl, or 8-ethyl-8-tricyclodecyl A resist composition. The method of claim 18, The comonomer is composed of a norbornene derivative, wherein the photosensitive polymer has the following structure. Wherein R ₄ is a hydrogen atom, a hydroxyl group, a halogen group, an alkyl group, a fluorinated alkyl group, an alkoxy group, an aldehyde group, an ester group, a nitrile group, a sulfonated group, and l / (l + m + n) = 0.1 to 0.4, m / (l + m + n) = 0.2 to 0.5, and n / (l + m + n) = 0.2 to 0.5. The method of claim 22, R ₄ is an acid-labile ester group decomposable by an acid of C ₅ to C ₁₄ or a fluorinated alcohol group of C ₃ to C ₁₀ . The method of claim 22, R ₄ is a t-butyl ester group, tetrahydropyranyl ester group, or a 1-ethoxyethyl ester group, characterized in that the resist composition. The method of claim 22, R ₄ is 2-methyl-2-adamantyl ester group, 2-ethyl-2-adamantyl ester group, 2-propyl-2-adamantyl ester group, 2-methyl-2-norbornyl ester Group, 2-ethyl-2-norbornyl ester group, 2-methyl-2-isobornyl ester group, 2-ethyl-2-isobornyl ester group, 8-methyl-8-tricyclodecyl ester group, Or an 8-ethyl-8-tricyclodecyl ester group. The method of claim 22, Wherein R ₄ is a 2-trifluoromethyl-1,1,1-trifluoro-2-hydroxypropyl group. The method of claim 22, The photosensitive polymer further comprises a repeating unit consisting of a styrene derivative represented by the following formula. Wherein R ₅ is a hydrogen atom, a hydroxy group, a halogen group, an alkyl group, a fluorinated alkyl group, an alkoxy group, an aldehyde group, an ester group, a nitrile group, a sulfonated group, and l / (l + m + n + o) = 0.1 to 0.4, m / (l + m + n + o) = 0.2 to 0.5, n / (l + m + n + o) = 0.2 to 0.5, o / (l + m + n + o) = 0.2 to 0.5. The method of claim 27, Wherein R ₅ is a 2-hydroxyhexafluoroisopropyl group resist composition. The method of claim 15, The PAG is resist composition, characterized in that contained in an amount of 1.0 to 15% by weight based on the weight of the photosensitive polymer. The method of claim 15, The PAG is composed of triarylsulfonium salts (triarylsulfonium salts), diaryliodonium salts (diaryliodonium salts) or a mixture thereof. The method of claim 15, The PAG comprises a triphenylsulfonium triflate, diphenyl iodonium triflate, di-t-butylphenyl iodonium triflate or a mixture thereof. The method of claim 15, The organic base is a resist composition, characterized in that contained in an amount of 0.01 to 2.0% by weight based on the weight of the photosensitive polymer. The method of claim 15, The organic base is a resist composition, characterized in that consisting of an organic tertiary amine. The method of claim 15, Wherein said organic base is comprised of triethylamine, triisobutylamine, triisooctylamine, diethanolamine, triethanolamine, or mixtures thereof.