KR20070067840A - Dissolution inhibitor and chemically amplified photoresist composition including the same - Google Patents

Abstract

Provided is a dissolution inhibitor, which enhances transparency in the short wavelength of 248 and 193nm and dry etching resistance to form ultrafine resist patterns and increase solubility difference between an exposure portion and a non-exposure portion in a developer solution to improve line edge roughness and resolution. The dissolution inhibitor has a structure represented by the following formula(1), wherein R is a straight, branched, monocyclic, or polycyclic aliphatic hydrocarbon having 1-30 carbon atoms and n is an integer of 1-4. The dissolution inhibitor is prepared by reacting a hydrocarbon having a vinyloxide group with 3,5-bis(hexafluoro-2-hydroxy-2-propyl)cyclohexyl alcohol, wherein the hydrocarbon having a vinyloxide group is obtained by reacting a hydrocarbon containing an alcohol group with acetylene.

Description

Dissolution inhibitor and chemically amplified photoresist composition including the same}

1 to 5 are electron scanning micrographs of photoresist patterns formed using photoresist compositions according to Examples and Comparative Examples of the present invention, respectively.

The present invention relates to a dissolution inhibitor and a chemically amplified resist composition comprising the same, and more particularly, a dissolution inhibitor and a chemically amplified resist composition including the same, which can increase the solubility difference between the exposed portion and the non-exposed portion in a photolithography process. It is about.

Recently, as the degree of integration of semiconductor devices increases, development of a dynamic random access memory (hereinafter referred to as DRAM) having a storage capacity of more than a gigabit level has been actively conducted. In order to manufacture a DRAM of 1 gigabit or more, it is required to form an ultrafine pattern having a line width of less than half pitch of 90 nm. For this purpose, an KrF excimer laser (248 nm) or a shorter ArF excimer laser (193 nm) is used as an exposure source. Photolithography technology has been introduced, and as the exposure source becomes shorter in wavelength, the development of a photoresist having high resolution and excellent transparency, dry etching resistance, and adhesiveness is urgently required. In general, the photoresist composition for ArF excimer laser should have high transparency at 193 nm wavelength, dry etching resistance and high adhesion to the underlying film, and to the 2.38 wt% tetramethylammonium hydroxide (TMAH) aqueous solution widely used as developer. Affinity should be high. In particular, the finer the pattern, the better the resolution and line edge roughness characteristics of the resist composition, and the thickness of the photoresist layer should be reduced in order to prevent pattern collapse. Etch resistance should be better.

In conventional ArF excimer laser (193 nm) resists, bulky cyclic or polycyclic cyclic compounds such as isobonyl, adamantyl, and tricyclodecanyl are introduced into the polymer resin to improve transparency and dry etching resistance. The method was used a lot. However, as the thickness of the resist continues to decrease, the method of increasing only the bulkyness of aliphatic ring compounds in the polymer resin limits the adhesion to the underlying film quality and increases the line edge roughness or worses the shape of the pattern. Showed. Therefore, in order to increase transparency and improve dry etching resistance, development of additives having excellent transparency and dry etching resistance as well as bulkiness control of the resin itself is required.

Accordingly, an object of the present invention is to provide a dissolution inhibitor and a chemically amplified resist composition including the same, which can improve transparency and dry etching resistance under short wavelength exposure sources such as 248 nm and 193 nm to form an excellent ultra-fine resist pattern.

Another object of the present invention is to suppress the diffusion of acid generated in the exposed portion into the resist to reduce the line edge roughness, to increase the post-exposure bake temperature stability (PEB sensitivity), and to prevent the swelling and includes It is to provide a chemically amplified resist composition.

In order to achieve the above object, the present invention provides a dissolution inhibitor represented by the following formula (1).

[Formula 1]

In Formula 1, R is a linear, branched, monocyclic, or polycyclic aliphatic hydrocarbon having 1 to 30 carbon atoms, and n is an integer of 1 to 4.

The present invention also comprises a dissolution inhibitor represented by the formula (1); Photosensitive polymer resins; It provides a chemically amplified photoresist composition comprising a photoacid generator for generating an acid and an organic solvent.

Hereinafter, the present invention will be described in more detail.

The dissolution inhibitor for photoresists according to the present invention is represented by the following formula (1).

,

,

또는

이고(여기서, 나선(

)은 연결부(connecting bond)를 나타낸다.), n은 1 내지 4의 정수이다.In Formula 1, R is a linear, branched, monocyclic, or polycyclic aliphatic hydrocarbon having 1 to 30 carbon atoms, preferably

,

,

or

And (where spirals (

) Represents a connecting bond.) N is an integer of 1 to 4.

Preferred examples of the dissolution inhibitor according to the present invention are compounds represented by the following Chemical Formulas 1a to 1d.

The dissolution inhibitor represented by Chemical Formula 1 includes linear, cyclic, and polycyclic bulky saturated hydrocarbons, for example, aliphatic ring hydrocarbons and trifluoromethyl (CF ₃ ) groups having high electronegativity, and thus transparency of photoresist. And improve dry etching resistance properties. In addition, in the exposed portion, the saturated hydrocarbon at the terminal including the cyclohexyl group is decomposed by the action of acid, and is easily dissolved due to an increase in affinity for the developing solution.In the non-exposed portion, the swelling phenomenon is prevented due to the acidity similar to phenol. The solubility in the developer can be suppressed to improve the contrast, resulting in a pattern with improved line edge roughness and resolution.

The dissolution inhibitor according to the present invention can be synthesized by various known organic synthesis methods. For example, as shown in Scheme 1 below, a hydrocarbon containing a vinyl oxide group is prepared by reacting a hydrocarbon containing an alcohol (OH) group with acetylene, and then a hydrocarbon containing a vinyl oxide group as shown in Scheme 2 below. A dissolution inhibitor represented by Chemical Formula 1 may be prepared by reacting with 3,5-bis (hexafluoro-2-hydroxy-2-propyl) cyclohexyl alcohol.

In Schemes 1 and 2, R and n are as defined in Formula 1.

The reaction may be performed in an organic solvent such as tetrahydrofuran, methylene chloride, acetone, acetonitrile, etc. In Scheme 2, a catalyst such as pyridinium p-toluenesulfonate may be used. The reaction of Scheme 1 may be performed for 10 to 12 hours at a temperature of 20 to 200 ℃, preferably 100 to 120 ℃, 1 to 50 atm, preferably 5 to 6 atm, the reaction of Scheme 2 It can be performed at room temperature for 48 hours.

In addition, the present invention is a dissolution inhibitor represented by the formula (1); Photosensitive polymer resins; Photoacid generators generating acid; And it provides a chemically amplified photoresist composition comprising an organic solvent.

The dissolution inhibitor represented by Chemical Formula 1 improves the contrast by increasing the solubility difference between the non-exposed part and the exposed part, and the content of the dissolution inhibitor is 0.1 to 50% by weight, preferably 0.1 to 20% by weight based on the total photoresist composition. %to be. When the content of the dissolution inhibitor is less than 0.1% by weight, the desired dissolution inhibiting effect cannot be obtained. When the content of the dissolution inhibitor exceeds 50% by weight, more -COOH is generated in the exposure area, which affects the non-exposure area. As a result, the contrast is lowered, dark erosion occurs, and film loss is caused.

As the photosensitive polymer resin, a photosensitive polymer resin conventionally used for preparing a chemically amplified photoresist composition may be used without limitation. The weight average molecular weight (Mw) of the photosensitive polymer resin is usually 1,000 to 150,000, and may include an alkali insoluble or soluble functional group. The content of the polymer resin is preferably 1 to 50% by weight, more preferably 1 to 20% by weight based on the total photoresist composition. If the content of the polymer resin is less than 1% by weight, the resist layer remaining after coating is too thin to form a pattern having a desired thickness. If the content exceeds 50% by weight, the coating uniformity may be deteriorated.

The photoacid generator generates an acid component such as H ⁺ by exposure, and serves to deprotect the protecting group of the photosensitive polymer resin, and a compound capable of generating an acid by light may be used without limitation. Onium-based compounds such as sulfone-based compounds such as N-iminosulfonate, disulfone, bisarylsulfonyldiazomethane, arylcarbonylarylsulfonyldiazomethane, and onium salt, and iodine Ionium salt compounds and mixtures thereof can be used. Non-limiting examples of the photoacid generator include diphenyl iodonium hexa fluorophosphate, diphenyl iodonium hexafluoro arsenate, diphenyl iodonium hexafluoro antimonate, diphenyl paramethoxy phenyl sulfonium tri Plate, diphenylparatoluenylsulfonium triflate, diphenylparaisobutylphenylsulfonium triflate, triphenylsulfonium hexafluoro phosphate, triphenylsulfonium hexafluoro arsenate, triphenylsulfonium hexafluoro Antimonate, triphenylsulfonium triflate, dibutylnaphthylsulfonium triflate, phthalimidotrifluoromethanesulfonate, dinitrobenzyltosylate, n-decyldisulfone, naphthylimidotrifluoromethanesulfonate, Mixtures thereof and the like can be exemplified. The content of the photoacid generator is preferably 0.1 to 50% by weight, more preferably 0.1 to 20% by weight based on the total photoresist composition. If the content of the photoacid generator is less than 0.1% by weight, the sensitivity of the photoresist composition to light decreases, which may cause deprotection of the protecting group. If the photoacid generator exceeds 50% by weight, the photoacid generator absorbs a lot of ultraviolet rays. There is a possibility that a large amount of acid is generated, resulting in poor cross section of the resist pattern.

As the organic solvent, various organic solvents commonly used in the preparation of the photoresist composition may be widely used. Non-limiting examples include ethylene glycol monomethyl ethyl, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, and diethylene. Glycol monoethyl ether, propylene glycol monomethyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclohexanone, 2-hydroxypropionethyl, 2-hydroxyethyl 2-ethylpropionate, ethyl ethoxy acetate, ethyl hydroxy acetate , 2-hydroxy methyl 3-methylbutyrate, methyl 3-methoxy 2-methylpropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxy 2-methylpropionate, ethyl acetate, n-heptanone, ethyl lac Tate, butyl acetate, a mixture thereof, etc. can be illustrated. The content of the organic solvent is 0.1 to 98.8% by weight, preferably 30 to 98% by weight based on the total photoresist composition.

In addition, the resist composition of the present invention may further include an organic base, if necessary, non-limiting examples of the organic base is triethylamine, triisobutylamine, triisooctylamine, diethanolamine, triethanolamine and Mixtures of these can be exemplified. The content of the organic base is preferably 0.01 to 20% by weight based on the total photoresist composition. When the content of the organic base is less than 0.01% by weight, a t-top phenomenon may occur in the resist pattern, and when the content is more than 20% by weight, the sensitivity of the photoresist composition may be lowered, thereby lowering the process progress rate. .

In order to form a photoresist pattern using the photoresist composition according to the present invention, first, the photoresist composition is applied to a substrate such as a silicon wafer or an aluminum substrate using a spin coater to form a photoresist film. After exposing the photoresist film in a predetermined pattern, the exposed photoresist pattern is heated (PEB: Post Exposure Bake), a photoresist pattern is formed by a conventional photolithography process of developing, and then a semiconductor device having a desired pattern is formed. It can manufacture. As a developing solution used in the developing step, an alkaline aqueous solution in which an alkaline compound such as sodium hydroxide, potassium hydroxide, sodium carbonate and tetramethylammonium hydroxide (TMAH) is dissolved at a concentration of 0.1 to 10% by weight may be used. Accordingly, an appropriate amount of a water-soluble organic solvent such as methanol and ethanol and a surfactant may be added to the developer. In addition, after the development process, the cleaning process may be further performed to clean the substrate with ultrapure water.

Hereinafter, the present invention will be described in more detail with reference to specific examples. The following examples are intended to illustrate the present invention more specifically, but the scope of the present invention is not limited by the following examples.

Example 1-1 Preparation of a Dissolution Inhibitor of Formula 1a

end. Preparation of 1,4-cyclohexane dimethanol divinyl ether

14.42 g (0.10 mol) of 1,4-cyclohexane dimethanol was added to the high pressure reactor, and dissolved in 40 g of tetrahydrofuran, followed by addition of 6.51 g (0.25 mol) of acetylene. Next, the mixture in the reactor was reacted while stirring for 10 to 12 hours at a temperature of 100 to 120 ° C. and an atmospheric pressure of 5 to 6 atm. After the reaction was completed, the reaction was separated by column chromatography (solvent: hexane, ethyl acetate) and dried to obtain 9.23 g of 1,4-cyclohexane dimethanol divinyl ether in 47% yield as in Scheme 3 below. {1H-NMR (CDCl ₃ , internal standard): δ (ppm) 3.92 (CH ₂ , 2H), 1.74 (CH, 2H), 1.40 (CH ₂ , 4H)}.

I. Preparation of Dissolution Inhibitor represented by Formula 1a

10.81 g (0.025 mol) of 3,5-bis (hexafluoro-2-hydroxy-2-propyl) cyclohexyl alcohol and 1.96 g (0.010 mol) of 1,4-cyclohexane dimethanol divinyl ether were added to a 100 ml flask. After the addition, 30 g of tetrahydrofuran was added and dissolved. Subsequently, 0.10 g of pyridinium p-toluenesulfonate as a catalyst was added thereto, and reacted with stirring at room temperature for 48 hours. After the reaction was completed, the reaction was separated by column chromatography (solvent: hexane, ethyl acetate) and dried to obtain 4.45 g of a dissolution inhibitor represented by Chemical Formula 1a in a yield of 42% as in Scheme 4 below. 1 H-NMR (CDCl ₃ , internal standard): δ (ppm) 1.76 (CH, 2H), 1.40 (CH ₂ , 4H), 3.33 (CH ₂ , 1H), 4.37 (CH, 2H), 1.36 (CH ₃ , 2H), 2.79 (CH, 2H), 1.53 (CH ₂ , 4H), 1.50 (CH, 4H), 1.36 (CH ₂ , 1H), 3.20 (OH, 4H)}.

Example 1-2 Preparation of Dissolution Inhibitor represented by Formula 1b

end. Preparation of 4,4'-isopropylidene divinyloxy cyclohexane

24.03 g (0.10 mol) of 4,4'-isopropylidenedicyclohexanol was put into a high pressure reactor, and it melt | dissolved in 40 g of tetrahydrofuran, and 6.51 g (0.25 mol) of acetylene were added. Next, the mixture in the reactor was reacted while stirring for 10 to 12 hours at a temperature of 100 to 120 ° C. and an atmospheric pressure of 5 to 6 atm. After the reaction was completed, the reaction was separated by column chromatography (solvent: hexane, ethyl acetate) and dried, and 11.03 g of 4,4'-isopropylidene divinyloxy cyclohexane was 36% as in Scheme 5 below. Yield {1H-NMR (CDCl ₃ , internal standard): δ (ppm) 3.44 (CH, 2H), 1.77 (CH ₂ , 4H), 1.40 (CH ₂ , 4H), 1.41 (CH, 2H), 1.11 (CH ₃ , 2H)}.

I. Preparation of Dissolution Inhibitor represented by Formula 1b

10.81 g (0.025 mol) of 3,5-bis (hexafluoro-2-hydroxy-2-propyl) cyclohexyl alcohol and 2.92 g (0.010 mol) of 4,4'-isopropylidene divinyloxy cyclohexane The reaction was carried out in the same manner as in the "b of Example 1-1" except for the one. After the reaction was completed, the reaction was separated by column chromatography (solvent: hexane, ethyl acetate), and dried to obtain 4.63 g of a dissolution inhibitor represented by Chemical Formula 1b as shown in Scheme 6 below in a yield of 40% { 1 H-NMR (CDCl ₃ , internal standard): δ (ppm) 2.79 (CH, 4H), 1.53 (CH ₂ , 4H), 1.50 (CH, 4H), 1.36 (CH ₂ , 2H), 3.20 (OH, 4H), 4.37 (CH, 2H), 1.36 (CH ₃ , 2H), 1.40 (CH ₂ , 4H), 1.41 (CH, 2H), 1.57 (CH ₂ , 4H), 1.11 (CH ₃ , 2H)}.

Example 1-3 Preparation of Dissolution Inhibitor represented by Formula 1c

end. Preparation of 2-vinyloxyadamantane

15.22 g (0.10 mol) of 2-adamantol were added to a high-pressure reactor, and dissolved in 40 g of tetrahydrofuran, followed by addition of 6.51 g (0.25 mol) of acetylene. Next, the mixture in the reactor was reacted while stirring for 10 to 12 hours at a temperature of 100 to 120 ° C. and an atmospheric pressure of 5 to 6 atm. After the reaction was completed, the reaction was separated by column chromatography (solvent: hexane, ethyl acetate) and dried to give 8.02 g of 2-vinyloxyadamantane in 45% yield as in Scheme 7 below. NMR (CDCl ₃ , internal standard): δ (ppm) 3.42 (CH, 1H)}.

I. Preparation of Dissolution Inhibitor represented by Formula 1c

Except for using 10.81 g (0.025 mol) of 3,5-bis (hexafluoro-2-hydroxy-2-propyl) cyclohexyl alcohol and 1.78 g (0.010 mol) of 2-vinyloxyadamantane, The reaction was carried out in the same manner as in "I" of Example 1-1. After the reaction was completed, the reaction was separated by column chromatography (solvent: hexane, ethyl acetate), and dried to obtain 2.69 g of a dissolution inhibitor represented by Chemical Formula 1c as shown in Scheme 8 below in a yield of 44%. 1H-NMR (CDCl ₃ , Internal standard): δ (ppm) 2.77 (CH, 1H), 4.37 (CH, 1H), 2.79 (CH, 1H), 1.53 (CH ₂ , 2H), 1.50 (CH, 2H ), 1.36 (CH ₂ , 1H), 1.36 (CH ₃ , 1H), 3.20 (OH, 2H)}

Example 1-4 A Dissolution Inhibitor Prepared by Formula 1d

end. Preparation of 1,3,5-trivinyloxycyclohexane

13.22 g (0.10 mol) of 1,3,5-cyclohexanetriol was added to the high pressure reactor, and dissolved in 40 g of tetrahydrofuran, followed by 9.11 g (0.35 mol) of acetylene. Next, the mixture in the reactor was reacted while stirring for 10 to 12 hours at a temperature of 100 to 120 ° C. and an atmospheric pressure of 5 to 6 atm. After the reaction was completed, the reaction was separated by column chromatography (solvent: hexane, ethyl acetate), dried, and 6.94 g of 1,3,5-trivinyloxycyclohexane in 33% yield as in Scheme 9 below. Obtained {1H-NMR (CDCl ₃ , internal standard): δ (ppm) 3.44 (CH, 3H), 2.10 (CH ₂ , 3H)}.

I. Preparation of Dissolution Inhibitor represented by Formula 1d

15.13 g (0.035 mole) of 3,5-bis (hexafluoro-2-hydroxy-2-propyl) cyclohexyl alcohol and 2.10 g (0.010 mole) of 1,3,5-trivinyloxycyclohexane were used. And reacted in the same manner as in "b of Example 1-1". After the reaction was completed, the reaction was separated by column chromatography (solvent: hexane, ethyl acetate), and dried to obtain 4.82 g of a dissolution inhibitor represented by Chemical Formula 1d as shown in Scheme 10 below in a yield of 32% { 1 H-NMR (CDCl ₃ , internal standard): δ (ppm) 2.79 (CH, 6H), 1.70 (CH ₂ , 3H), 4.37 (CH, 3H), 1.36 (CH ₃ , 3H), 1.53 (CH ₂ , 6H), 1.50 (CH, 6H), 1.36 (CH ₂ , 3H), 3.20 (OH, 4H)}.

[Examples 2-1 to 2-4] Preparation of a photoresist composition comprising a dissolution inhibitor prepared in Examples 1-1 to 1-4

0.12 g of the dissolution inhibitor (Formula 1a) prepared in Example 1-1 and 4.0 g of the polymer resin represented by the following Formula 2 (weight average molecular weight: 1,000 to 150,000) and 0.04 g of triphenylsulfonium triflate were added to propylene glycol mono After dissolving in 53 g of methyl ether acetate, it was filtered through a 0.2 μm disk filter to prepare a photoresist composition (Example 2-1). Also, instead of 0.12 g of the dissolution inhibitor prepared in Example 1-1, a photoresist composition was prepared in the same manner except that 0.12 g of the dissolution inhibitor prepared in Examples 1-2 to 1-4 was used. (Examples 2-2 to 2-4).

[Examples 3-1 to 3-4, Comparative Example 1] Exposure pattern formation using photoresist composition

Photoresist compositions having the same components as Examples 2-1 to 2-4 and having a thickness of about 0.2 except that the photoresist compositions prepared in Examples 2-1 to 2-4 and the dissolution inhibitor were not included After the spin coating on the etched layer of the silicon wafer coated with an organic anti-reflection film to a ㎛ to prepare a photoresist thin film, and prebaked for 90 seconds in an oven or hot plate at 130 ℃, ArF laser exposure equipment having a numerical aperture of 0.60 After exposure, it was again baked for 130 ° C. The heated wafer was immersed in a 2.38 wt% TMAH aqueous solution for 30 seconds and developed to obtain a rectangular 0.09 μm line and space pattern when the exposure amount was about 20 mJ / cm 2. Physical properties of the formed photoresist pattern are shown in Table 1 below, and electron scanning micrographs of the photoresist patterns formed using the compositions prepared in Examples 2-1 to 2-4 and Comparative Example 1 are shown in FIGS. 1 to 5. Respectively.

Resist composition Sensitivity (mJ / ㎠) Dry etching resistance Line edge roughness Example 2-1 20 Great 2.5nm Example 2-2 22 Great 3.1nm Example 2-3 26 Great 4.5nm Example 2-4 18 Great 3.9 nm Comparative Example 1 28 usually 6.6 nm

From Table 1, it can be seen that the resist composition comprising a dissolution inhibitor according to the present invention is superior in terms of dry etching resistance and line edge roughness than a resist composition without a dissolution inhibitor (Comparative Example 1).

As described above, the dissolution inhibitor according to the present invention and the photoresist composition including the same increase the transparency and dry etching resistance under the short wavelength exposure sources of 248 nm and 193 nm, thereby forming an excellent ultra fine pattern, as well as an exposed part and a non-exposed part. Increasing the difference in solubility of the developer in the solution can improve the line edge roughness and increase the resolution.

Claims (6)

Dissolution inhibitor represented by the following formula (1). [Formula 1]

In Formula 1, R is a linear, branched, monocyclic, or polycyclic aliphatic hydrocarbon having 1 to 30 carbon atoms, and n is an integer of 1 to 4. The method of claim 1, wherein the dissolution inhibitor is a 3,5-bis (hexafluoro-2-hydroxy-2-propyl hydrocarbon containing a vinyl oxide group produced by reacting a hydrocarbon containing an alcohol (OH) group and acetylene Dissolution inhibitor prepared by reacting with cyclohexyl alcohol. The dissolution inhibitor according to claim 1, wherein the dissolution inhibitor is selected from a compound consisting of a group represented by the following Chemical Formulas 1a to 1d. [Formula 1a]

[Formula 1b]

[Formula 1c]

[Formula 1d]

A dissolution inhibitor represented by Formula 1; Photosensitive polymer resins; Photoacid generators generating acid; And  Chemically Amplified Photoresist Compositions Containing Organic Solvents The method of claim 4, wherein the content of the dissolution inhibitor represented by the formula (1) relative to the entire photoresist composition is 0.1 to 50% by weight, the content of the polymer resin is 1 to 50% by weight, the content of the photoacid generator 0.1 to 50% by weight, the content of the organic solvent is 0.1 to 98.8% by weight of the chemically amplified photoresist composition. The method of claim 4, wherein the organic solvent is ethylene glycol monomethyl ethyl, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether acetate (PGMEA), toluene, xylene, methyl Ethyl ketone, cyclohexanone, 2-hydroxypropionethyl, 2-hydroxyethyl 2-methylpropionate, ethyl ethoxy acetate, ethyl hydroxyacetate, 2-hydroxy 3-methylbutyrate, 3-methoxy 2 A chemistry selected from the group consisting of methyl methyl propionate, ethyl 3-ethoxypropionate, ethyl 3-methoxy 2-methylpropionate, ethyl acetate, n-heptanone, ethyl lactate, butyl acetate and mixtures thereof Amplified photoresist composition.

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