KR101738480B1 - Photoresist composition for forming self-aligned double pattern - Google Patents

Abstract

상기 화학식 1에서, R₁은 각각 독립적으로 수소 또는 메틸기이고, R₂는, 수소 또는 탄소수 1 내지 5의 선형 또는 분지형 알킬기이고, R₃는 탄소수 4 내지 10의 락톤기 또는 락톤기를 포함하는 알킬기이고, R₄는 히드록시기 및 불소기로 치환된 탄소수 8 내지 15의 알킬기이고, X는 산소 또는 에스테르기이며, a, b, c 및 d는 상기 고분자를 이루는 전체 단량체에 대한 각 반복 단위의 몰%로서, 각각 20 내지 60몰%, 10 내지 60몰%, 20 내지 60몰% 및 0 내지 30몰%이다.Disclosed is a photoresist composition for self-aligned double pattern formation which can cause a reduction in the thickness of a photoresist film and a pattern of an unexposed portion. Wherein the photoresist composition comprises 0.5 to 15% by weight of a polymer represented by the following formula (1); And the remaining solvent. In the developing process for removing the boundary layer, the developer causes a reduction in the thickness of the photoresist film and the pattern of the unexposed area.
[Chemical Formula 1]

Wherein R ₁ is independently hydrogen or a methyl group, R ₂ is hydrogen or a linear or branched alkyl group having 1 to 5 carbon atoms, and R ₃ is an alkyl group having a lactone group or a lactone group having 4 to 10 carbon atoms , R ₄ is an alkyl group having 8 to 15 carbon atoms substituted with a hydroxyl group and a fluorine group, X is an oxygen or ester group, and a, b, c and d are mole percentages of the respective repeating units with respect to the total monomers constituting the polymer , 20 to 60 mol%, 10 to 60 mol%, 20 to 60 mol% and 0 to 30 mol%, respectively.

Description

[0001] Photoresist compositions for forming self-aligned double patterns [

The present invention relates to a photoresist composition, and more particularly, to a photoresist composition and a photoresist composition of a photoresist composition of a non-exposed portion by a developer for removing a boundary layer in a self-aligned double patterning process and a boundary layer removing process for forming a second photoresist pattern. To a photoresist composition for self-aligned double pattern formation capable of causing a reduction in the thickness of the pattern.

As the degree of integration of semiconductor devices increases, a photolithography process capable of forming an ultrafine photoresist pattern having a line width of 80 nm or less is required. In a typical photolithography process, a photoresist composition containing a photosensitive polymer and a solvent is coated on a substrate such as a silicon wafer used for manufacturing an integrated circuit, and the resultant is baked to evaporate the solvent, Thereby forming a film-shaped photoresist film. Next, by irradiating light of a predetermined pattern from the exposure source and exposing the photoresist film according to the pattern of the exposure source, the chemical properties of the photosensitive polymer are changed in the exposed area. Examples of the light used for such exposure include visible light, ultraviolet (UV) light, electron beam, X-ray, and the like. After the exposure, the exposed photoresist film is treated with a developer solution to selectively dissolve and remove the exposed or unexposed portions of the photoresist film to form a photoresist pattern.

In such a photolithography process, various techniques for increasing the resolution of the photoresist pattern have been developed, and self-aligned double patterning technology (SaDPT) is exemplified. 1, a self-aligned double patterning technique is used in which a boundary layer (CAP) 22 is formed on the first photoresist pattern 20 on the substrate 10 (FIG. 1A) The second photoresist film 32 is formed by removing the boundary layer 22 after forming the second photoresist film 30 (FIG. 1B) thereby increasing the resolution. However, since the developing solution such as a tetramethyl ammonium hydroxide (TMAH) aqueous solution for removing the boundary layer 22 can not dissolve the second photoresist film 30, When the second photoresist film 30 is present on the upper portion, the above process is not performed smoothly.

Therefore, it has become necessary to develop a photoresist composition which can reduce the thickness of the unexposed second photoresist film 30 by the developer for removing the boundary layer 22. [

Accordingly, an object of the present invention is to provide a photoresist composition for self-aligned double pattern formation which can cause a reduction in the thickness of the photoresist film and the pattern of the non-exposure area by the developer.

It is another object of the present invention to provide a photoresist composition for self-aligned double pattern formation which does not cause an allign issue in the formation of the second photoresist pattern.

In order to accomplish the above object, the present invention provides a polymer composition comprising 0.5 to 15% by weight of a polymer represented by the following formula (1); And the remaining solvent, and the thickness of the photoresist film and the pattern of the non-exposed portion in the developing process is reduced.

[Chemical Formula 1]

Wherein R ₁ is independently hydrogen or a methyl group, R ₂ is hydrogen or a linear or branched alkyl group having 1 to 5 carbon atoms, and R ₃ is a linear or branched group containing a lactone group or a lactone group having 4 to 10 carbon atoms , Branched, single ring or polycyclic alkyl group, R ₄ is a linear, branched, monocyclic or polycyclic alkyl group of 8 to 15 carbon atoms substituted with a hydroxyl group and a fluorine group, X is an oxygen or ester group, and a, b , c and d are mole% of each repeating unit with respect to the total monomer (repeating unit) constituting the polymer, and a, b, c and d are 20 to 60 mol%, 10 to 60 mol%, 20 to 60 mol % And 0 to 30 mol%.

The photoresist composition for self-aligned double pattern formation according to the present invention can be formed by a developer such as tetramethyl ammonium hydroxide (TMAH) aqueous solution, a photoresist film of an unexposed portion (that is, in a non-exposed state) The pattern may be reduced in thickness. Therefore, in the photoresist pattern forming method using the self-aligned double patterning technology (SaDPT), the second photoresist film formed on the boundary layer (CAP) can be easily removed. Therefore, in the self-aligned double patterning technique (process) using a conventional photoresist composition, a separate exposure process for removing the second photoresist film formed on the boundary layer (CAP) is required, but in the present invention, So that a process shortening effect can be obtained. In addition, the conventional double patterning technique for performing the exposure process two times may cause an alignment problem that the second photoresist pattern is not precisely positioned between the first photoresist patterns. However, The resist composition forms a second photoresist pattern between the first photoresist patterns only by forming a photoresist film dissolved in the developing solution without developing the photoresist film and developing (removing the boundary layer), so that the cause of the alignment problem Secondary exposure and mask alignment of the exposure system are not required, which is useful for self-aligned double patterning techniques.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view for explaining a process of forming a photoresist pattern by a self-aligned double patterning technique. FIG.
2 is a SEM photograph of a photoresist pattern according to Example 3-1 of the present invention.

Hereinafter, the present invention will be described in detail.

The photoresist composition for self-aligned double patterning according to the present invention can be used for forming a second photoresist film and a pattern in a self-aligned double patterning process (self-aligned double patterning technology: SaDPT) The thickness of the photoresist film and the pattern (second photoresist film and pattern) in the non-exposed state is reduced by the developer for removing the boundary layer in the boundary layer removing step for forming the second photoresist pattern And includes a polymer represented by the following general formula (1) and a solvent.

Wherein R ₁ is independently hydrogen or a methyl group and R ₂ is hydrogen or a linear or branched alkyl group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms. R ₃ is a linear, branched, monocyclic or polycyclic alkyl group containing a lactone group or a lactone group having 4 to 10 carbon atoms, preferably 4 to 8 carbon atoms, for example, a single lactone structure or a lactone group is added to an alkyl group , And a structure in which an alkyl group is added to the lactone group. R ₄ is a linear, branched, monocyclic or polycyclic alkyl group having 8 to 15 carbon atoms, preferably 8 to 13 carbon atoms, substituted with a hydroxyl group and a fluorine group, X is an oxygen or ester group, and a, b, A, b, c and d are each in the range of 20 to 60 mol%, 10 to 60 mol%, 20 to 60 mol% and 0 to 30 mol%, respectively, as molar percentages of the respective repeating units of the polymer , Preferably 30 to 50 mol%, 20 to 40 mol%, 30 to 40 mol% and 0 to 10 mol%, respectively. If the recurring units of c mol% and d mol% are too small, the reduction of the thickness of the second photoresist film in the development (removal of the second photoresist film and the boundary layer on the boundary layer) is insufficient after the formation of the second photoresist film There is a possibility that the second photoresist film may not be developed. If the second photoresist film is too large, the thickness of the second photoresist film may be excessively reduced and the pattern may not be formed. In particular, when the mole% of the repeating unit d is too large, the stability of the resist may be impaired. On the other hand, when the d% by mole of the repeating unit is used, the minimum amount thereof is, for example, 0.5 mol%, preferably 1 mol%.

The polymer (photosensitive polymer) represented by the above formula (1) used in the present invention is preferably a polymer having a repeating unit (c mol% repeating unit) containing a fluoroalcohol group or the like or a repeating unit (D% by mole of repeating units) and acrylic acid groups (d% by mole of repeating units) are contained in the polymer chain, and the mole% of each repeating unit in the polymer is controlled, After the resist pattern is formed, the boundary layer removal such as tetramethyl ammonium hydroxide (TMAH), sodium hydroxide (NaOH), and potassium hydroxide (KOH) The developer can control the degree of the decrease in the thickness of the film (develop loss, film loss, and thickness). The content of the polymer is 0.5 to 15% by weight, preferably 1 to 10% by weight and more preferably 3 to 7% by weight based on the total photoresist composition. If the content of the polymer is less than 0.5% by weight, The resist film and the pattern formation may become difficult. When the content exceeds 15% by weight, the thickness of the formed photoresist film becomes thick, so that the secondary pattern can not be easily formed, and the thickness distribution of the formed pattern may be uneven. The weight average molecular weight (Mw) of the polymer is 5,000 to 100,000, preferably 5,000 to 20,000. When the weight average molecular weight of the polymer is out of the above range, the solubility with the solvent may be lowered, or the secondary resist may not be completely filled in the space of the pattern.

Representative examples of the polymer represented by the formula (1) include the following formulas (2) to (10).

In Formulas 2 to 10, a, b, c and d are as defined in Formula 1 above.

The solvent used in the present invention is to dissolve the polymer. An organic solvent used in a conventional photoresist composition may be used without limitation, for example, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol Monoacetate, diethylene glycol, diethylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, propylene glycol, propylene glycol monoacetate, toluene, xylene, methyl ethyl ketone, methyl isoamyl ketone, cyclohexanone, dioxane N, N-dimethylacetamide, N, N-dimethylacetamide, N-methylmorpholine, N-methylmorpholine, 2-pyrrolidone, 3-ethoxyethyl propionate, 2-heptanone, gamma-butyrolactone, 2-hydroxypropionyl ethyl, 2- Ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxy-2-methylpropionate, ethyl 3-ethoxypropionate, 3-methoxy Methyl ethyl ketone, ethyl 2-methylpropionate, ethyl acetate, butyl acetate, etc. may be used alone or in a mixture of 2 to 4 thereof. The content of the solvent is the balance excluding 100% by weight of the entire photoresist composition except additives such as the polymer and photoacid generator.

The photoresist composition according to the present invention may further contain a photoacid generator, a basic acid diffusion controlling agent (basic compound, Quencher) and the like, if necessary.

The photoacid generator (PAG) used in the present invention is preferably used in the case where an additional process for partially removing the photoresist pattern in the space direction is performed after the boundary layer removing process, to expose the photoresist on the boundary layer more easily A compound capable of generating an acid by light can be used without limitation, for example, a sulfonium salt-based or iodonium salt-based compound, a mixture thereof, and the like can be used. Preferable examples include triphenylsulfonium triflate, phthalimidotrifluoro methanesulfonate, dinitrobenzyltosylate, n-decyl disulfone, naphthylimidotrifluoro Naphthylimidotrifluoro methanesulfonate, diphenyl iodide salt triflate, diphenyl iodide salt nonaplate, diphenyl iodide salt hexafluorophosphate, diphenyl iodide salt hexafluoroarsenate, diphenyl iodide salt hexafluoroantimonate, di Phenyl para-methoxyphenylsulfonium triflate, diphenyl para-toluenesulfonium triflate, diphenyl para-tertiary butyl phenyl sulfonium triflate, diphenyl paraisobutyl phenyl sulfonium triflate, triphenyl sulfonium triflate, Tri-tert-butylphenylsulfonium triflate, diphenyl para-methoxyphenylsulfonium tri Plate, a diphenyl para-toluenesulfonium nonaplate, a diphenyl para-tertiary butylphenylsulfonium nonaplate, a diphenyl paraisobutylphenylsulfonium nonaplate, a triphenylsulfonium nonaplate, a triisasparturic butylphenylsulfonium Nona plate, hexafluoroarsenate, triphenylsulfonium hexafluoroantimonate, dibutylnaphthylsulfonium triflate, mixtures thereof, and the like can be used.

The content of the photoacid generator is 0.5 to 15 parts by weight, preferably 1 to 8 parts by weight, based on 100 parts by weight of the polymer represented by the formula (1). If the amount of the photoacid generator is less than 0.5 parts by weight based on 100 parts by weight of the polymer represented by Formula 1, the reactivity to the exposure source is lowered and the portion to be removed (portion remaining in the space portion of the pattern) There is a fear that it may not be removed, and if it exceeds 15 parts by weight, the sensitivity to the exposure source may not be easily controlled.

The basic acid diffusion control agent used in the present invention is used for controlling the diffusion of acid, and basic acid diffusion control agents used in conventional photoresist compositions can be used without limitation, for example, triethylamine, tri It may be selected from one or more kinds selected from octylamine, triisobutylamine, triisooctylamine, diethanolamine, triethanolamine and 2-piperidine ethanol.

When the basic acid diffusion control agent is used, its content is 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the polymer represented by the formula (1). If the amount of the basic acid diffusion control agent is less than 0.5 part by weight, it is difficult to control the acid diffusion by the exposure source. When the amount exceeds 10 parts by weight, excessive acid diffusion is suppressed, ). ≪ / RTI >

As shown in FIG. 1, the self-aligned double patterning process (self-aligned double patterning technology (SaDPT)) according to the present invention is a process of forming a self- Forming a first photoresist pattern 20 on the first photoresist pattern 20 and forming a boundary layer CAP 22 by coating a material for forming a boundary layer CAP on the first photoresist pattern 20, The photoresist composition for self-aligned double patterning according to the present invention is applied to the first photoresist pattern 20 on which the boundary layer 22 is formed and is exposed at a temperature of, for example, 80 to 150 캜, preferably 95 to 125 캜 (FIG. 1B) forming a second photoresist film 30 by baking the first photoresist film 30 for 40 to 120 seconds, preferably 50 to 60 seconds, The second photoresist film 30 is developed and removed, And a cast pattern 20, a second photoresist step (C in Fig. 1) to form the pattern 32 in between. When the temperature and the time are out of the above ranges in the baking of the photoresist composition for self-aligned double pattern formation, since the solvent is insufficiently removed or the difference in solubility due to the denaturation by the temperature of the protecting group in the polymer becomes excessively small or large , There is a possibility that formation of a photoresist film becomes difficult.

The first photoresist pattern 20 may be formed through a conventional photoresist composition and a photolithography process without particular limitation. For example, a first photoresist composition made of a conventional photoresist composition is applied onto a semiconductor substrate 10 on which a crystallographic layer is formed to form a first photoresist film, and a soft bake (for example, at a temperature of 95 to 125 DEG C Exposing the first photoresist film to an exposure energy (Eop) capable of achieving an optimum pattern using an exposure mask having a line and space pattern; Post-baking (post-exposure bake, PEB) at a temperature of 150 캜 for 30 to 180 seconds, and developing the resultant. The first photoresist pattern 20 can be formed.

The boundary layer (CAP) 22 is provided between the first photoresist pattern 20 and the second photoresist pattern 32 for protection of the first photoresist pattern 20 and a coating layer for forming a space portion after the DPT process. (CAP) forming material. The water-soluble polymer may be a water-soluble polymer such as polyvinylpyrrolidone, polyacrylamide, polyimidazole, or the like containing an ordinary water-soluble polymer such as a nitrogen group. 10% by weight, a water-soluble anionic surfactant, a cationic surfactant or an amphoteric surfactant such as an alkylbenzenesulfonate surfactant, a higher amine halide, a quaternary ammonium salt surfactant, an alkyl pyridinium salt surfactant, 0.01 to 3.0% by weight of a coating film-forming agent such as a surfactant, a sulfonimide-based surfactant, and the like, and a solvent such as deionized water, Baking at a temperature of 150 캜 for 30 to 180 seconds. The boundary layer may be formed to have various thicknesses depending on the resolving power of the pattern, and may be formed usually to a thickness of 30 to 300 nm. An example of such a boundary layer (CAP) forming material and a self-aligned double patterning (SaDPT) process is disclosed in the applicant's PCT international application PCT / KR2010 / 001226 and the entire content of the PCT international application is incorporated herein by reference .

Hereinafter, the present invention will be described in more detail with reference to specific examples. The following examples illustrate the present invention and are not intended to limit the scope of the present invention.

[Preparation Example 1-1] Preparation of polymer represented by formula (2)

To the reactor were added 12.4 g (0.05 mol) of 2-ethyl-2-adamantyl methacrylate, 4.25 g (0.03 mol) of 2-methyl-acrylic acid-2-oxo-tetrahydrofuran- (0.03 mol) of acrylic acid-5- (3,3,3-trifluoro-2-hydroxy-2-trifluoromethyl-propyl) -bicyclo [2.2.1] hept- And 0.7 g of azobis (isobutyronitrile) (AIBN). The reaction product was dissolved in 100 g of anhydrous tetrahydrofuran (THF), the gas was removed by using an ampoule by a freezing method, The removed reaction product was polymerized for 24 hours at 68 DEG C. After the polymerization reaction was completed, the reaction was precipitated with slow addition of excess diethyl ether, then dissolved again in THF, and the dissolved reaction was extracted with diethyl ether Reprecipitated to obtain 14.4 g of the polymer represented by Formula 2 at a yield of 56%. The number average molecular weight (Mn), weight average molecular weight (Mw) and polydispersity (PD) of the polymer synthesized by GPC (Gel Permeation Chromatography) were analyzed (GPC analysis: Mn = 5,020, Mw = PD = 1.81}.

[Preparation Example 1-2] Preparation of polymer represented by formula (3)

(3,3,3-trifluoro-2-hydroxy-2-trifluoromethyl-propyl) -bicyclo [2.2.1] hept-2-yl ester (3,3,3-trifluoro-2-hydroxy-2-trifluoromethyl-propyl) -bicyclo [2.2.1] hept-2-yl ester was used instead of the acrylic acid 5- (GPC analysis: Mn = 4,630, Mw = 8,241, Mw = 8,241) was obtained in the same manner as in Preparation Example 1-1, except that 8.65 g (0.03 mol) PD = 1.78}.

[Preparation Example 1-3] Preparation of polymer represented by formula (4)

(3,3,3-trifluoro-2-hydroxy-2-trifluoromethyl-propyl) -bicyclo [2.2.1] hept-2-yl ester (5-vinyloxy-bis-quail [2.2.1] hept-2-ylmethyl) -propan-2- 11.8 g of the polymer represented by Formula 4 was synthesized in 48% yield in the same manner as in Preparation Example 1-1 except that 7.95 g (0.03 mol) of 2,2'-azobisisobutyronitrile was used. (GPC analysis: Mn = 4,582, Mw = 7,560, PD = 1.65}.

[Preparation Example 1-4] Preparation of a polymer represented by the formula (5)

(3,3,3-trifluoro-2-hydroxy-2-trifluoromethyl-propyl) -bicyclo [2.2.1] hept-2-yl ester Except that 9.05 g (0.03 mol) of 2-methyl-acrylic acid 1-cyclohexyl-4,4,4-trifluoro-3-hydroxy-3-trifluoromethyl- (GPC analysis: Mn = 4,935, Mw = 7,995, PD = 1.62) in a yield of 46% in the same manner as in Preparation Example 1-1.

[Preparation Example 1-5] Preparation of the polymer represented by the formula (6)

(3,3,3-trifluoro-2-hydroxy-2-trifluoromethyl-propyl) -bicyclo [2.2.1] hept-2-yl ester (2,2,2-trifluoro-1-hydroxy-1-trifluoromethyl-ethyl) -cyclohexyl ester was used instead of 2-methyl-acrylic acid 3,5- (GPC analysis: Mn = 5,103, Mw = 8,369, PD = 1.64) was obtained in the same manner as in Preparation Example 1-1, except that the polymer represented by Formula }.

[Production Example 1-6] Preparation of the polymer represented by the formula (7)

(0.05 mol) of 2-ethyl-2-adamantyl methacrylate, 3.40 g (0.03 mol) of 2-methyl-acrylic acid-2-oxo-tetrahydrofuran- 7.20 g (0.02 mol) of acrylic acid-5- (3,3,3-trifluoro-2-hydroxy-2-trifluoromethyl-propyl) -bicyclo [2.2.1] hept- , 0.86 g (0.01 mol) of 2-methyl-acrylic acid and 0.7 g of azobis (isobutyronitrile) (AIBN) were put in a reaction vessel and the reaction product was dissolved in 100 g of anhydrous tetrahydrofuran (THF) the gas was removed using an ampoule, and the degassed reaction was polymerized at 68 DEG C for 24 hours. After completion of the polymerization reaction, the reaction product was slowly added dropwise to an excessive amount of diethyl ether, precipitated, dissolved again in THF, and the dissolved reaction product was reprecipitated in diethyl ether to obtain 57% (GPC analysis: Mn = 5,368, Mw = 9,426, PD = 1.75).

[Production Example 1-7] Preparation of a polymer represented by the formula (8)

Hydroxy-2-trifluoromethyl-propyl) -bicyclo [2.2.1] hept-2-yl ester (7.20 g, (5-vinyloxy-bis-quail [2.2.1] hept-2-ylmethyl) -propan-2- 11.7 g of a polymer represented by the above formula (8) was synthesized in 51% yield in the same manner as in Preparation Example 1-6 except that 6.36 g (0.02 mol) of 2,2'-biphenyl was used. (GPC analysis: Mn = 4,210, Mw = 7,199, PD = 1.71}.

[Production Example 1-8] Preparation of the polymer represented by the formula (9)

Hydroxy-2-trifluoromethyl-propyl) -bicyclo [2.2.1] hept-2-yl ester (7.20 g, Except that 7.24 g (0.02 mol) of 2-methyl-acrylic acid 1-cyclohexyl-4,4,4-trifluoro-3-hydroxy-3-trifluoromethyl- (GPC analysis: Mn = 4,390, Mw = 7,770, PD = 1.77) in a yield of 49% in the same manner as in Preparation Example 1-6.

[Preparation Example 1-9] Preparation of polymer represented by formula (10)

Hydroxy-2-trifluoromethyl-propyl) -bicyclo [2.2.1] hept-2-yl ester (7.20 g, (2,2,2-trifluoro-1-hydroxy-1-trifluoromethyl-ethyl) -cyclohexyl ester was used instead of 2-methyl-acrylic acid 3,5- (GPC analysis: Mn = 4,821, Mw = 8,099, PD = 1.68) was obtained in the same manner as in Preparation Example 1-6, except that the polymer represented by Formula 10 was used in a yield of 42% }.

[Examples 1-1 to 1-9] Preparation of photoresist composition

As shown in the following Table 1, 2.0 g of the polymers (Formulas 2 to 10) prepared in Production Examples 1-1 to 1-9, 0.08 g of triphenylsulfonium triflate and 0.02 g of triethanolamine were dissolved in propylene glycol monomethyl ether Acetate (PGMEA), followed by filtration through a 0.2 mu m disk filter to prepare a photoresist composition.

Polymer Photoacid generator Basic acid diffusion control agent Organic solvent Example 1-1 2.00 g Triphenylsulfonium
Tree plate
0.08 g Triethanolamine
0.02 g PGMEA 17g Examples 1-2 (3) Example 1-3 (4) 2.00 g Examples 1-4 2.00 g of Formula 5 Examples 1-5 2.00 g of Formula 6 Examples 1-6 (7) 2.00 g Examples 1-7 (8) 2.00 g Examples 1-8 (9) 2.00 g Examples 1-9 (10) 2.00 g

[Examples 2-1 to 2-9 and Comparative Examples] Preparation of photoresist film and evaluation of thickness variation

The photoresist compositions prepared in Examples 1-1 to 1-9 and the general ArF photoresist composition (product name: DHA-3606, manufactured by Dongjin Semichem Co., Ltd.) as a comparative example were immersed in 200 nm thick hexamethyldisilazane (HMDS) was spin-coated on top of the etching layer of a silicon wafer to prepare a photoresist film (Examples 2-1 to 2-9 and Comparative Example).

Next, the prepared photoresist film was subjected to a soft heat treatment in an oven or a hot plate at 120 캜 for 90 seconds, immersed in a 2.38% by weight aqueous solution of tetramethylammonium hydroxide (TMAH) for 60 seconds to develop, And the results are shown in Table 2 below.

The initial photoresist film
Thickness (nm) After the development process
Photoresist film thickness (nm) thickness
Change (nm) Example 2-1 200 194 6 Example 2-2 200 191 9 Example 2-3 200 192 8 Examples 2-4 200 189 11 Example 2-5 200 171 29 Examples 2-6 200 174 26 Examples 2-7 200 165 35 Examples 2-8 200 169 31 Examples 2-9 200 152 48 Comparative Example 200 200 0

[Examples 3-1 to 3-9] Photoresists using self-aligned double patterning technique Manufacture of patterns

Photoresist composition DHA-3606 (manufactured by Dongjin Semichem) was coated on the wafer and soft baked at 110 캜 for 60 seconds. After soft bake, an exposure mask having a line and space (L / S) pattern was used and exposed using a 193 nm ArF exposure equipment (ASML 1200B) and post-baked at 110 DEG C for 60 seconds. After post-baking, the resultant was developed with an aqueous solution of 2.38 wt% tetramethylammonium hydroxide (TMAH) to obtain a first photoresist pattern of 50 nm L / S and 1: 3 pitch.

4.0 g of polyvinylpyrrolidone (PVP) as a water-soluble polymer, 95.0 g of deionized water, and 1.0 g of a sulfonimide as a coating film forming agent (surfactant) were coated on the first photoresist pattern, Baked at 150 캜 for 60 seconds, and then developed with deionized water to form a boundary layer having a thickness of 6 nm on the first photoresist pattern.

The photoresist composition of each of Examples 1-1 to 1-9 was applied to the resultant, baked at 110 ° C for 60 seconds, developed with 2.38 wt% tetramethylammonium hydroxide (aqueous TMAH) solution without exposure, (The boundary layer upper photoresist film and the boundary layer were removed) to obtain second photoresist patterns (Examples 3-1 to 3-9) of 60 nm L / S and 1: 3 pitch. 2 is a scanning electron microscope (SEM) photograph of the photoresist pattern according to Example 3-1.

It can be seen from Table 2 that the photoresist films (Examples 2-1 to 2-9) prepared using the photoresist compositions (Examples 1-1 to 1-9) according to the present invention use general ArF photoresist compositions (Comparative example), the photoresist film showed partial solubility in the TMAH developer. Thus, in the case of using the photoresist composition according to the present invention, in a self-aligned double patterning technology (SaDPT) process, without any additional process for removing the second photoresist film such as an exposure process, The second photoresist film and the boundary layer may be removed to form a second photoresist pattern (Examples 3-1 to 3-9), and the second photoresist pattern may be located at the center between the first photoresist patterns It is possible to solve the alignment problem which can not be solved and it is useful for the DPT process such as the self-aligned double patterning technique.

Claims (5)

0.5 to 15% by weight of a polymer represented by the following formula (1); And
The remaining solvent,
In the self-aligned double patterning process, in the boundary layer removing process for forming the secondary photoresist pattern, a self-aligned double patterning / RTI >
[Chemical Formula 1]

Wherein R ₁ is independently hydrogen or a methyl group, R ₂ is hydrogen or a linear alkyl group having 1 to 5 carbon atoms or a branched alkyl group having 3 to 5 carbon atoms, R ₃ is a lactone group having 4 to 10 carbon atoms, R ₄ is a linear, branched, monocyclic or polycyclic alkyl group having 8 to 15 carbon atoms substituted with a hydroxyl group and a fluorine group, X is an oxygen or ester group A, b, c and d are mole% of each repeating unit with respect to the total monomer constituting the polymer, and a, b, c and d are 20 to 60 mol%, 10 to 40 mol%, 20 to 60 mol% Mol% and 0.5 to 30 mol%. The photoresist composition according to claim 1, wherein the polymer represented by the formula (1) is selected from the group consisting of polymers represented by the following formulas (7) to (10).
(7)

[Chemical Formula 8]

[Chemical Formula 9]

[Chemical formula 10]

A, b, c and d are mole% of each repeating unit with respect to all the monomers constituting the polymer, and a, b, c and d are 20 to 60 mol%, 10 to 40 mol %, 20 to 60 mol% and 0.5 to 30 mol%. The photoresist composition according to claim 1, further comprising 0.5 to 15 parts by weight of a photoacid generator based on 100 parts by weight of the polymer represented by the formula (1). The photoresist composition according to claim 1, further comprising 0.5 to 10 parts by weight of a basic acid diffusion control agent based on 100 parts by weight of the polymer represented by the formula (1). Forming a first photoresist pattern on a substrate and coating a boundary layer forming material on the first photoresist pattern to form a boundary layer;
A photoresist composition for forming a self-aligned double pattern containing 0.5 to 15% by weight of a polymer represented by the following formula (1) and the remaining solvent is applied to the first photoresist pattern having the boundary layer formed thereon, baked, Forming a photoresist film,
[Chemical Formula 1]

Wherein R ₁ is independently hydrogen or a methyl group, R ₂ is hydrogen or a linear alkyl group having 1 to 5 carbon atoms or a branched alkyl group having 3 to 5 carbon atoms, R ₃ is a lactone group having 4 to 10 carbon atoms, R ₄ is a linear, branched, monocyclic or polycyclic alkyl group having 8 to 15 carbon atoms substituted with a hydroxyl group and a fluorine group, X is an oxygen or ester group A, b, c and d are mole% of each repeating unit with respect to the total monomer constituting the polymer, and a, b, c and d are 20 to 60 mol%, 10 to 40 mol%, 20 to 60 mol% Mol% and 0.5 to 30 mol%; And
And forming a second photoresist pattern between the first photoresist patterns by developing and removing the second photoresist film above the boundary layer and the boundary layer without exposing the second photoresist film .

Images