KR19990029309A - Crosslinkable aqueous base developable photoresist compositions and methods for their use - Google Patents

Abstract

There is disclosed a high-resolution photoresist composition capable of developing an aqueous base for use in deep-UV and i-lines. The compositions of the present invention comprise a phenolic polymer resin, a crosslinking agent selected from glycouril derivatives capable of reacting with these resins under acid catalyzed reaction, a photoacid generator, and an organic solvent. The compositions of the present invention are particularly useful for producing high resolution negative tone images (less than 0.25 mu m).

Description

Crosslinkable aqueous base developable photoresist compositions and methods for their use

The present invention relates to an aqueous base developable photoresist composition and a method for forming a lithographic pattern therewith.

In the electronics industry, there has been constant effort to achieve higher circuit densities in electronic components. In order to achieve higher densities, new and improved lithographic tools and techniques have been developed and new photoresists are needed that can improve the resolution of lithographic patterns.

An aqueous base developable photoresist composition formed through crosslinking is disclosed in Reck et al., (SPIE Regional Technical Conference on Photopolymers, Ellenville, N.Y., 63 (1988); And U.S. Pat. Nos. 5,034,304 and 5,204,225 to Feely. Such formulations are characterized by having aromatic moieties which are susceptible to electrophilic aromatic substitution, i. E. Poly (hydroxystyrene) or novolacs, and a photoacid generator capable of forming a carbonium ion upon treatment with an acid .

U.S. Patent No. 4,810,601 to Allen et al. Is directed to a method for crosslinking an aromatic compound with a monomeric or polymeric source of carbonium ions to form a negative tone resist pattern. Thus, diacetoxymethylbenzene and trisacetoxymethylene are used in conjunction with triphenylsulfonium hexafluoroantimonate to crosslink the poly (hydroxystyrene) matrix.

U.S. Patent No. 5,296,332 to Sachdev and Japanese Patent Nos. 90-15270 and 89-293339 to Kokai disclose that phenolic resins such as poly (hydroxystyrene) or novolak ), A crosslinking agent capable of forming a carbonium ion upon treatment with an acid, and a photoacid generator.

A broad aspect of the present invention is an aqueous base developable photoresist composition for generating a negative tone resist image of less than 0.25 탆 on a substrate. Another embodiment of the present invention is a photoresist composition which does not form micro-crosslinking between resist phases on a substrate. Such photoresist compositions comprise (a) a film forming polymer resin having a phenolic group, (b) an acid labile crosslinking agent selected from an aminoplast class and more specifically a glycoluril derivative, (c) a crosslinking agent of a film forming agent and a crosslinking agent (D) optionally an organic base to enhance the shelf life stability of the formulation. The phenolic polymer resin of the present invention comprises a poly (hydroxystyrene) of the following formula 1, a partially protected poly (hydroxystyrene) of the following formula 2, a hydroxystyrene-vinyl cyclohexanol copolymer of the following formula 3, 4 < / RTI > novolac (phenol-formaldehyde) resin:

The crosslinking agent of the composition of the present invention is selected from glycouril derivatives of formula (5)

In this formula,

R is alkoxyalkyl, preferably CH ₂ OCH ₃ ,

R ₁ and R ₂ are individually selected from hydrogen, alkyl and aryl groups.

The composition of the present invention also comprises a radiation decomposable acid generator.

Another broad aspect of the present invention is a process for the synthesis of novel glycouril derivatives which act as crosslinking agents for such compositions.

The present invention also

a) coating the substrate with a film comprising a film-forming polymeric resin having phenolic functional groups, an acid-catalyzable crosslinking agent selected from glycouril derivatives, a radiation-decomposable acid generator,

b) exposing the film to UV radiation in an upward direction to cause cross-linking at the exposed portion of the film,

c) calcining the substrate at elevated temperature,

d) developing the film in an aqueous base developer

A method of using a novel resist composition for generating a negative tone resist image on a substrate.

The composition of the present invention is sensitive to far ultraviolet radiation. The resist speed can be adjusted by adjusting the ratio of the crosslinked umbellation polymer resin, adding an organic base and / or adding a partially protected poly (hydroxystyrene) or novolac.

Figures 1 to 3 are photomicrographs depicting phases produced using different compositions of the present invention.

The present invention relates to a high resolution, aqueous base developable photoresist composition for generating a negative tone image on a substrate. These compositions comprise (a) a film forming polymer resin having a phenolic functional group, (b) a glycouril derivative crosslinking agent capable of reacting with the phenolic functional group during the acid catalyzed reaction to form a crosslinking, (c) (D) an organic base (e.g., a tertiary amine) that is specifically added to increase the shelf life of the formulation and to control the light flux. The polymeric resin and the phenolic functional group are selected from poly (hydroxystyrene) of the following formula 1, partially protected poly (hydroxystyrene) of the following formula 2 and hydroxystyrene-vinyl cyclohexanol copolymer of the formula 3:

Formula 1

(2)

(3)

In this formula,

R can be an alkyl group including C _1-4 alkyl, acetyl, hydroxyalkyl, acetoxyalkyl (CH ₃ COCH ₂ CH ₂ -),

y is from 0.5 to 1, n is greater than 1, preferably greater than 20, and most preferably n is greater than 20 and less than 100. Preferred cross-linking agents for compositions of the present invention are glycoluril derivatives of formula 5:

Formula 5

In this formula,

R is alkoxyalkyl, preferably CH ₂ OCH ₃ ,

R ₁ and R ₂ are each independently selected from alkyl groups having 1 to 6 carbon atoms,

a) tetrakis-methoxymethyl-3a, 6a-diethylglycouryl,

b) tetrakis-methoxymethyl-3a-methyl-6-propylglycouuryl of the formula 5b,

c) tetrakis-methoxymethyl-3a-methyl-6a-butylglycouryl of formula 5c,

R ₁ and R ₂ may also be selected from alkyl and aryl groups or hydrogen, with examples of glycouril derivatives such as (d) tetrakismethoxymethyl-3-phenylglycouiryl and (e) Methoxy methyl-3a-methyl-6a-phenylglycouol, such as 5e,

R ₁ and R ₂ may all be phenyl, furyl or alkylphenyl and halogenated aryl groups or substituted diphenyl ether groups, wherein examples of glycouril derivatives are the same as those of the following formulas 5f to 5h:

The compositions of the present invention are also preferably prepared from an onium salt of Group IV as disclosed in U.S. Patent No. 4,175,972, incorporated herein by reference, and an aromatic onium salt of Group Va as disclosed in U.S. Patent No. 4,069,055, And a photoacid generator (PAG) that can be selected. The aromatic onium salt of group IVa comprises a compound of formula 6:

[(R) _a (R ¹ ) _b (R ² ) _c X] d ⁺ [MQ _e ] ^{- (ef)}

In this formula,

R is a monovalent aromatic organic radical,

R < ¹ > is a monovalent organic aliphatic radical selected from alkyl, cycloalkyl and substituted alkyl,

R < ² > is a multivalent organic radical that forms a heterocyclic or fused ring structure, X is an atom of group IVa or a metalloid,

Q is a halogen radical,

a is 0 or more and 3 or less,

b is 0 or more and 2 or less,

c is 0 or 1;

The radicals contained in R include, for example, aromatic hydrocarbon radicals having 6 or more carbon atoms such as phenyl, tolyl, naphthyl, anthryl, 1-4 of which are radicals such as C _1-8 alkyl, C _1-8 alkoxy, (E.g., pyridyl and furyl), aryl radicals (e.g., pyridyl and furyl), heteroaryl radicals (e.g., pyridyl and furyl)

R ¹ radicals are C _1-8 alkyl, substituted alkyl (such as -C ₂ H ₄ OCH ₃ , -CH ₂ -COCH _3, etc.)

The R < ² >

, , And the like.

MQ _e of the formula (6) ^- complex anion contained in the ^(ef), for example, ^{_{BF 4 -, PF 6 -,}} SbF 6 -, FeCl 4 -, SnCl 6 -, SbCl 6 -, BiCl 5 -, AlF 6 - ³ , GaCl ₄ ^- , InF ₄ ^-, and the like.

The onium salt of the group VIa contained in the above general formula is, for example,

, , , to be.

Among the nonmetallic degradable acid generators suitable for use in the compositions of the present invention are the N-sulfonyloxyimides of the formula 7:

In this formula,

R is toluene, benzene, CF _3, CF ₂ CF ₃ and - is selected from (CF _{2) n} -Z group consisting of,

n is from 1 to 4,

Z is H or alkyl or aryl,

X and Y are independently selected from the group consisting of (1) forming a polycyclic ring containing or not containing a hetero atom, (2) forming a conjugated aromatic ring, or (3)

C ₁ and C ₂ may form a single bond or a double bond.

The compositions of the present invention also contain minor amounts of basic compounds selected from any organic amine, especially a tertiary amine.

The composition of the present invention is preferably performed in a solvent or solvent system. The solvent or solvent system used to carry these compositions preferably satisfies the requirement for uniformly coating the resist components on the substrate to the full application range. The solvent is preferably evaporated at a temperature such that the photoactivity of the resist does not adversely affect the drying step, and will not participate in the action of the photoresist (inert to the phenolic resin and / or the crosslinking agent). These common solvents are propylene glycol monomethyl ether acetate (PGMEA), ethyl-3-ethoxypropionate (EEP), methoxypropanol, ethoxypropanol, butoxypropanol, ethyl lactate.

For formation of the negative tone image, the composition of the present invention is coated onto the substrate (e.g., spin-coated) and the remaining solvent is evaporated by heating the substrate on a hot plate for 1 to 3 minutes to a temperature of about 70 to 130 캜 . Then, when the film is exposed upwardly to UV radiation having a wavelength of about 200 to 370 nm, the radiation decomposable component of the composition decomposes to form a catalytic amount of acid. The crosslinking reaction between the phenolic resin and the crosslinking agent is accelerated by heating the substrate at 70 to 130 DEG C for preferably 1 to 3 minutes. Thus, the phases become less soluble or insoluble in aqueous bases and development steps, and the exposed areas are removed by aqueous bases, such as dilute solutions of tetramethylammonium hydroxide (TMAH).

In another embodiment of the present invention, the glycouril derivative used as the cross-linking agent is synthesized from the corresponding dicarbonyl compound as shown in Scheme 1 below:

The glycouril derivatives of the present invention are highly soluble in selected organic solvents and, as compared to unsubstituted glycourols, lower the solubility of the final composition in the base developer.

General procedure for the preparation of alkyl-substituted glycourols

Synthesis of the alkyl-substituted glycourols described below is illustrated by the synthesis of 3a-methyl-6-propylglycouryl.

2,3-Hexanedione (1.0 mol) and urea (3.0 mol) are added to 2.0 L of 2% hydrochloric acid and the solution is stirred for 24 hours at room temperature (alternatively, the solution can be refluxed for 2 to 3 hours ). The precipitate is filtered, washed with water and ethanol and dried. The off-white powder is then crystallized in acetic acid to give the analytically pure title compound in 45% yield.

General procedure for the preparation of aryl-substituted glycourols

(1.0 mol) and urea (0.3 mol) are suspended in 300 mL of toluene and 5.0 mL of trifluoroacetic acid are added, with the appropriate benzyl derivative (Scheme 1, R ₁ and R ₂ being an aryl group or a combination of alkyl and aryl groups) . The resulting solution is refluxed for 8 hours, during which the water is removed via a Dean-Stark trap. The solution is cooled to room temperature and the precipitated crystalline material is filtered off, washed with toluene and hexane and dried.

Hydroxymethylation of glycourols

The glycoluril derivative (0.10 mol) is suspended in a 37% aqueous formaldehyde solution (0.5 mol) and the pH is adjusted to 10-11 by the addition of 10% sodium hydroxide. The resulting mixture is heated at 50 < 0 > C for 24 hours and all solids dissolved in solution. The solution is cooled to room temperature and the water is removed under reduced pressure. The residue (solid or gum) is used in the next step without further purification.

Etherification of aminoplast compounds

Tetrakis-hydroxymethylglycouril is suspended in excess 2,2-dimethoxypropane and converted to their corresponding tetramethoxymethyl derivative, a few drops of concentrated hydrochloric acid are added and the mixture is stirred at room temperature for 24 hours Lt; / RTI > The solvent is removed under reduced pressure and the residue is crystallized from an appropriate solvent (such as in the case of a diaryl or alkylaryl substituted glycoururil) or the oil residue is purified by distillation under high vacuum and elevated temperature (for example methylpropyl or methylbutyl To give the tetrakis-methoxymethyl derivative of the desired glycouril.

The following examples are a detailed description of the preparation method of the present invention and its use. Detailed manufacturing methods are within the scope of the more generally described methods described above and are intended to be illustrative. The embodiments are for illustrative purposes only and are not intended to limit or limit the scope of the invention.

Example 1

(10 g) of 4-hydroxystyrene-vinylcyclohexanol copolymer (the molar ratio of hydroxystyrene to vinylcyclohexane being 9: 1) and 3-methyl-6-propyl-tetrakis-methoxymethylglycol (1.0 g) and MDT (trifluoromethylsulfonyloxybicyclo [2.2.1] hept-5-ene-2,3-dicarboximide (100 mg) were dissolved in propylene glycol monomethyl ether acetate (PGMEA) The resulting solution was filtered through a 0.25 filter and spun coated on the substrate at 110. After calcining for 1 minute, a UV light of about 20 mJ at 248 nm was spotted using a 0.5 NA I- / Cm < 2 >. After exposure at 110 [deg.] C for 1 minute, the photoresist is developed in 0.26 N aqueous tetramethylammonium hydroxide. A high resolution image (Figure 1) is formed with a very distinct 220 nm line.

Example 2

A mixture of poly (4-hydroxystyrene) (10 g) and tetrakis-tetramethoxymeth-3a, 6a-bis- [4- (4-t- butylphenoxy) phenyl] glycoururil (0.45 g) - Methoxymethylglycouril (Powderlink, 0.8 g) and MDT (1.20 g) are dissolved in 50 mL of PGMEA. The solution is spin-coated onto a silicon wafer to a dry thickness of 0.5 [mu] m and exposed through a mask at 248 nm UV light at about 20 mJ / cm2. The substrate is then calcined at 110 DEG C for 1 minute and developed in a 0.26 N aqueous tetramethylammonium hydroxide solution and rinsed with water. A high-resolution image of 0.22 mu m or less is formed as shown in an SEM micrograph (Fig. 2).

Example 3

(1.1 g) of poly (hydroxystyrene) (10 g), tetrakis-methoxymethyl-3a-methyl-6a-butylglycoluril (1.1 g) and MDT (1.2 g) were dissolved in 50 g of PGMEA and filtered do. The resulting solution is spin-coated onto a silicon wafer to a dry thickness of about 0.6 mu. The wafer is calcined at 90 DEG C and excess solvent is removed and exposed to 248 nm UV light at 20 mJ / cm < 2 > using a 0.5 NA step and a repeat tool. After exposure, the wafer is calcined at 95 DEG C for 1 minute and then developed in 0.14 N aqueous tetramethylammonium hydroxide. (Fig. 3) of a 200 nm line.

A high-resolution negative tone image (less than 0.25 mu m) can be produced by the aqueous base developable photoresist composition of the present invention.

Claims (23)

(a) providing on a substrate an uncured film comprising a phenolic resin or polymer, a glycoluril derivative, a photoacid generator, an organic solvent, (b) exposing the film to ultraviolet light in a predetermined pattern in an upward direction to generate an acid catalyst in the pattern, (c) calcining the exposed film at 90 to 130 DEG C for 1 to 2 minutes, (d) developing the photoresist in an aqueous base solution ≪ / RTI > The method according to claim 1, Wherein the wavelength of ultraviolet light is from about 250 to about 370 nm. The method according to claim 1, Wherein the phenolic resin is poly (4-hydroxystyrene). The method according to claim 1, Wherein the phenolic resin is a copolymer of hydroxystyrene and hydroxycyclohexylethynyl of Formula 3: (3) In this formula, n is greater than 1, X is 0 or more and 1 or less, and Y is 0 or more and 1 or less. The method according to claim 1, Wherein the phenolic resin is a partially-protected poly (hydroxystyrene) of formula 2: (2) In this formula, X is from 0.5 to 1.0, R is an organic radical. The method according to claim 1, Wherein the phenolic resin is a phenol-formaldehyde (novolak) resin. The method according to claim 1, Wherein the glycoluril derivative is represented by the general formula Wherein R ₁ and R ₂ are independently selected from the group consisting of alkyl, alkenyl, alkoxy, aryl (phenyl, furyl, thienyl), alkylaryl having 1 to 6 carbon atoms such as tolyl, xylyl, mesityl or C _n H _{2n + 1} C ₆ H ₄ -, wherein n is 3 to 6, halogenated aryl, diphenyl ether and diphenyl sulfide. The method according to claim 1, Wherein the photoacid generator is selected from onium salts of Group IV elements. The method according to claim 1, Wherein the photoacid generator is selected from an onium salt of the group VIa element. The method according to claim 1, Wherein the photoacid generator is selected from the sulfonates of the N-hydroxyimide. The method according to claim 1, Wherein the photoacid generator is a sulfonate of formula (7): < EMI ID = Formula 7 The method according to claim 1, A phenol resin or a polymer, a glycoluril derivative, a photoacid generator, a solvent From about 90% to about 60% of a phenolic resin or polymer, from about 5% to about 20% of a glycoluril derivative, About 2 to about 20% photoacid generator, about 0.02 to about 0.5% organic base, ≪ / RTI > (a) providing on a substrate a film of a mixture comprising a phenolic resin or polymer, a glycoluril derivative, a photoacid generator, an organic solvent, an organic base, (b) exposing the film to ultraviolet light in a predetermined pattern in an upward direction to generate an acid catalyst in the pattern, (c) calcining the exposed film, (d) developing the photoresist ≪ / RTI > A phenolic resin or polymer, a glycoluril derivative, a photoacid generator, an organic solvent, a mixture of organic bases. 15. The method of claim 14, Wherein the phenolic resin is poly (4-hydroxystyrene). 15. The method of claim 14, Wherein the phenolic resin is a copolymer of hydroxystyrene and hydroxycyclohexyl ethenyl of the following formula: (3) In this formula, n is greater than 1, X is 0 or more and 1 or less, and Y is 0 or more and 1 or less. 14. The method of claim 13, Wherein the phenolic resin is a partially protected poly (hydroxystyrene) of formula 2: (2) In this formula, X is from 0.5 to 1.0, R is an organic radical. 15. The method of claim 14, Wherein the phenolic resin is a phenol-formaldehyde (novolak) resin. 15. The method of claim 14, Wherein the glycoluril derivative is represented by the general formula Wherein R ₁ and R ₂ are independently selected from the group consisting of alkyl, alkenyl, alkoxy, aryl (phenyl, furyl, thienyl), alkylaryl having 1 to 6 carbon atoms such as tolyl, xylyl, mesityl or C _n H _{2n + 1} C ₆ H ₄ -, wherein n is 3 to 6, halogenated aryl, diphenyl ether and diphenyl sulfide. 15. The method of claim 14, Wherein the photoacid generator is selected from onium salts of Group IV elements. 15. The method of claim 14, Wherein the photoacid generator is selected from an onium salt of the group VIa element. 15. The method of claim 14, Wherein the photoacid generator is selected from sulfonates of N-hydroxyimides. 15. The method of claim 14, A phenol resin or a polymer, a glycoluril derivative, a photoacid generator, a solvent About 40 to about 80% of a phenolic resin or polymer, about 5 to about 25% of a glycoluril derivative, about 2.0 to about 20% of a photo-acid generator, and 0.01 to 0.5% A composition for forming a mixture.