KR100465448B1 - Photoresist composition - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to photoresist compositions that can be used to implement positive images in a variety of industries, including the electronics industry, such as semiconductors, LCDs, circuit boards, and the printing industry. Relates to a photoresist composition comprising a polyhydroxystyrene resin, (2) a crosslinking photosensitive agent, (3) a non-crosslinking photosensitive agent, (4) an organic base, and (5) an organic solvent, and the photoresist composition of the present invention. Using can easily form a pattern with excellent resolution.

Description

Photoresist composition

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to photoresist compositions that can be used to implement positive images in a variety of industries, including the electronics industry, such as semiconductors, LCDs, circuit boards, and the printing industry. The present invention relates to a photoresist composition capable of realizing high resolution by appropriately mixing a crosslinking type photosensitive agent capable of forming a crosslink with a polymer resin and a non-crosslinking type photosensitive agent as a photosensitive agent.

Photoresist refers to a polymer material that acts as a resist to form a fine pattern on a substrate when subjected to exposure, development, etching, or the like during semiconductor ultrafine processing. As the integration of semiconductors is progressing, high-resolution photoresist is required and the wavelength of light source used is developing from g-line (436nm) to i-line (365nm), KrF excimer laser (248nm) and ArF excimer laser (193nm). .

The photoresist composition is mainly prepared by dissolving a polymer resin containing a reactive group changeable in an aqueous alkali solution by catalysis of a photosensitive agent and an acid generated from the photosensitive agent in an organic solvent. In general, the polymer resin is appropriately selected in consideration of the absorbance of the polymer according to the wavelength of the light source, for example, novolak resin in the case of i-line photoresist, polyhydroxystyrene in the case of KrF photoresist In the case of resins and ArF photoresists, polyacrylate resins containing ring structures such as norbornene are mainly used. On the other hand, a sulfonium salt, an iodonium salt or an organic compound is used as the photosensitizer, and as the organic solvent, propylene glycol monomethyl ether acetate (PGMEA), ethyl cellosolve acetate (ECA) or ethyl lac Tate EL and the like are used.

The resist coating structure is largely divided into a non-crosslinked resist (protective-deprotective type) and a crosslinked resist. Conventional non-crosslinked resist composition is composed of a photoresist capable of generating an acid and a polymer resin containing a protecting group that can be dissociated by an acid generated from the photoresist, and there is no chemical bond between these two materials. There have been various problems such as loss of the photosensitive agent, neutralization of the generated acid by external pollutants, and formation of undesirable patterns.

On the other hand, the conventional crosslinking resist composition is composed of a polymer resin, a crosslinking agent and a non-crosslinking photosensitive agent, and the crosslinking agent reacts with the polymer during the prebake process to form a crosslink between the polymer and the polymer. Thereafter, crosslinking is broken by the acid generated by the exposure to cause a difference in solubility between the exposed portion and the non-exposed portion so that the image is expressed. Such a crosslinking resist has the advantage that the thermal stability of the non-exposed portion is increased by crosslinking. However, in this case, as the molecular weight of the polymer increases during the crosslinking process, the photoresist is more likely to be separated from the resist coating, which makes it difficult to fill the photoresist highly. It becomes difficult to produce. As a result, degradation of environmental stability and performance may occur.

Recently, in order to alleviate the above disadvantages, a crosslinking resist composition has been proposed in which a crosslinking is introduced between a polymer resin and a photosensitive agent by using a crosslinking photosensitive agent (see Korean Patent Publication No. 1999-31039, Korean Patent Application No. 2000-40202). However, they also have poor solubility in organic solvents, or improvement in evaporation of photoresist, diffusion rate of acid during exposure, and photospeed.

Accordingly, the present invention is to solve the problems of the prior art as described above, cross-linked photosensitive agent and non-crosslinking photosensitive agent which can crosslink with the polymer resin by heat treatment after forming a resist coating as a photosensitive agent, which can cause a cross-linking reaction during exposure It is an object of the present invention to provide a photoresist composition that exhibits high resolution by using a mixture in an appropriate ratio.

That is, the present invention (1) a polyhydroxy styrene resin having a structure of formula (1), (2) a crosslinking photosensitive agent having a structure of formula (2), (3) a non-crosslinking photosensitive agent having a structure of formula (3), It provides a photoresist composition comprising (4) an organic base, and (5) an organic solvent:

[Formula 1]

Wherein l, m and n are respectively 0.62 ≦ l / (l + m + n) ≦ 0.8, 0.04 ≦ m / (l + m + n) ≦ 0.06 and 0.16 ≦ n / (l + m + n) Is a real number satisfying ≤0.32)

[Formula 2]

[Formula 3]

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

The polymer resin used in the present invention is p- (1-ethyloxyethoxy) styrene / p- (t-butoxy having a structure in which a tertiary butoxycarbonate (t-BOC) group and an acetal group are substituted with some hydroxy groups of polyhydroxystyrene. Carbonyloxy) styrene / p-hydroxy styrene terpolymer {p- (1-ethyloxyethoxy) styrene / p- (t-butoxycarbonyloxy) styrene / p-hydroxystyrene terpolymer} is represented by the following formula (1).

Wherein l, m and n are 0.62 ≦ l / (l + m + n) ≦ 0.8, 0.04 ≦ m / (l + m + n) ≦ 0.06 and 0.16 ≦ n / (l + m + n) ≦ 0.32 must be satisfied, otherwise, an excellent pattern cannot be formed.

In the present invention, a crosslinking photosensitive agent and a non-crosslinking photosensitive agent are mixed as a photosensitive agent. The crosslinking photosensitive agent has di (4-vinyloxyethoxyphenyl) -2,6-dimethyl-4-methoxyphenyl having a structure represented by the following Chemical Formula 2 Sulfonium nona plate {Di (4-vinyloxyethoxyphenyl) -2,6-dimethyl-4-methoxyphenylsulfonium nonaflate}, and the non-crosslinked photosensitive agent has a structure of Formula 3 below (pt-butoxycarbonylmethoxyphenyl) diphenyl Sulfonium nonaplate {(p-tert-butoxycarbonylmethoxyphenyl) diphenylsulfonium nonaflate}.

According to the present invention, the mixing ratio of the crosslinkable photosensitive agent to the noncrosslinking photosensitive agent is preferably 1:10 to 10: 1. And the sum of the amount of these photosensitizers can be up to 0.5 parts by weight to 6 parts by weight relative to 100 parts by weight of the polyhydroxystyrene resin. If the content of the photosensitizer is less than 0.5 parts by weight, the photosensitivity is lowered, while if it exceeds 6 parts by weight, the resolution is rather deteriorated. Moreover, in this invention, it is also possible to use together general nonionic photosensitizers, such as bis (cyclohexylsulfonyl) diazomethane, in addition to the said two photosensitizers.

Meanwhile, in the present invention, an organic base is used for the purpose of reducing the influence of basic compounds such as amines contained in the atmosphere on the pattern obtained after exposure or controlling the shape of the pattern, preferably trihexyl. Tertiary amines such as amine (trihexylamine), triisobutylamine, triethanolamine, trioctylamine, triisodecylamine, trimethylene dipiperidine and the like; Ammonium salts such as tetrabutylammonium lactate and tetrabutylammonium hydroxide; Dicyclohexylamine, didecylamine, piperidine, piperazine, 1,3,5-trimethylhexahydro-1,3,5-triazine (1,3 , 5-trimethylhexahydro-1,3,5-triazine), 1,3,5-triethylhexahydro-1,3,5-triazine (1,3,5-triethylhexahydro-1,3,5-triazine) Secondary amines such as 1-piperidine ethanol; Primary amines such as 1-hexadecylamine, 1-hexadecylamine, octadecylamine and 4- (2-aminoethyl) phenol {4- (2-aminoethyl) phenol}; And 4-aminobenzoic acid, 3,4-dimethylaniline, 4-aminominolatrol, 4-aminnoveratrole, diphenylamine, triphenylamine One or more types of aromatic amines, such as these, are used.

The content of the organic base in the composition of the present invention is preferably 0.01 to 10 parts by weight based on 100 parts by weight of the polyhydroxystyrene resin. If the content of the organic base is less than 0.01 parts by weight, the desired pattern shape is not obtained, while if the content is more than 10 parts by weight, the photosensitivity is lowered.

The organic solvent used to dissolve the above-mentioned components is not particularly limited unless it impairs the purpose of the present invention, and is not limited to propylene glycol monomethyl ether acetate (PGMEA), ethyl cellosolve acetate (ECA) or ethyl lactate (EL). Is preferably used.

The content of the organic solvent is preferably 250 to 1000 parts by weight based on 100 parts by weight of the polyhydroxystyrene resin. When the content of the organic solvent is less than 250 parts by weight, precipitation occurs due to a decrease in solubility, whereas when it exceeds 1000 parts by weight, film formation becomes difficult.

Hereinafter, the present invention will be described in more detail with reference to examples, but these examples are for illustrative purposes only and should not be construed as limiting the present invention.

Preparation Example A Synthesis of Di (4-vinyloxyethoxyphenyl) -2,6-dimethyl-4-methoxyphenylsulfonium nonaplate

Preparation Example A-1 Synthesis of Bis (4-hydroxyphenyl) sulfoxide {Bis (4-hydroxyphenyl) sulfoxide}

1000 ml of acetone and 1.0 mol (218.27 g) of bis (4-hydroxyphenyl) sulfide} were added to the reactor, followed by stirring at room temperature for dissolution. 1 g of acetic acid was added continuously with stirring, and then cooled to 5 ° C. and 1.0 mol (114 g) of 30% H ₂ O ₂ was added dropwise while stirring, but this reaction was severe exothermic and the reaction temperature exceeded 30 ° C. Since reactant production is likely to be accelerated, the reaction temperature is slowly added dropwise, taking care not to exceed 25 ° C. After the addition was completed, the mixture was stirred at room temperature for 40 hours to mature. Subsequently, the temperature of the fruit was gradually raised from room temperature to 60 ° C., the reaction solution was distilled under reduced pressure at about 50 torr, and 2 L of methanol / water (1: 2 volume ratio) mixture was added to the white solid remaining in the reactor, and then stirred under about 70 It heated up to ° C and dissolved. After re-crystallization by cooling to room temperature under low temperature stirring, the crystals were recovered by filtration and dried at 60 ° C. for 5-10 hours using a vacuum dryer to obtain the title compound (yield 90%).

Preparation Example A-2: Synthesis of MPSC {bis (4-hydroxyphenyl) -3,5-dimethyl-4-methoxyphenyl sulfonium chloride}

After adding 60.8 g of phosphorus pentaoxide to the reactor, 608 g of methane sulfonic acid (MSA) solution was added thereto, the temperature was raised to 50 ° C. under stirring, and stirring was continued for about 5 hours to completely dissolve P 2 O 5. Thereafter, the solution was cooled to about 30 ° C., and then maintained at a temperature thereof, and 1 mol (234 g) of bis (4-hydroxyphenyl) sulfoxide obtained from Preparation Example A-1 was added thereto, followed by stirring for 30 minutes. . Subsequently, the reaction temperature was lowered to 10 to 15 ° C., and 1.01 mol (137.4 gr) of 2,6-dimethylanisol was slowly added thereto, but the reaction temperature was maintained at 25 ° C. or lower. After aging for 10 hours at room temperature. After completion of the reaction, the reaction solution is poured into a saturated aqueous NaCl solution in excess (about 5 times the volume of the reaction solution), but if the reaction is exothermic and the reaction temperature exceeds 20 ° C, a side reaction product is generated. The solution was poured slowly while maintaining the temperature not exceeding 10 ° C., and then the reaction solution was separated at room temperature without stirring for about 8 hours to obtain a white solid precipitate. The wet cake obtained by filtration of the solid was added to 3 to 4 L of ethanol, and stirred for about 1 hour at room temperature to dissolve. Subsequently, after adding about 1.5 volume of saturated NaCl aqueous solution of ethanol added above, it was recrystallized by standing at room temperature for about 1 day without stirring. The resulting crystals were collected by vacuum filtration and then dried in a vacuum dryer for 24 hours to give the title compound (yield 80%).

Preparation Example A-3 Di (4-vinyloxyethoxyphenyl) -2,6-dimethyl-4-methoxyphenylsulfonium nona plate {Di (4-vinyloxyethoxyphenyl) -2,6-dimethyl-4-methoxyphenylsulfonium nonaflate } Synthesis

2 L of DMSO (dimethyl sulfoxide), 1 mol (384.5 g) of MPSC obtained from Preparation Example A-2, 2 mol (85 g) of 95% NaOH, and 2 mol (213 g) of 2-chloroethyl vinyl ether were added thereto and then 80 to 100. After the temperature was raised to ℃, the reaction obtained by stirring for 2 hours was added to 10L of an aqueous solution of 0 ℃ containing 1 mol of sodium nonaflate and left for two days. The wet cake obtained by filtration was dissolved in 2.5 L of methanol, and the same volume of ethyl ether as methanol was added to make the solution opaque. The solution was left at room temperature for 1 day, recrystallized, filtered and recovered. The crystals were vacuum dried for 24 hours to afford the title compound (yield 65%).

Preparation Example B Synthesis of (p-t-butoxycarbonylmethoxyphenyl) diphenylsulfonium nonaplate

Preparation Example B-1: Synthesis of (p-t-butoxyphenyl) diphenylsulfonium chloride {(p-tert-butoxyphenyl) diphenylsulfonium chloride}

20.2 g (0.10 mol) of diphenyl sulfoxide dissolved in 200 g of methylene chloride was cooled using an ice bath. Then 5.3 g (0.052 mol) of triethylamine were added and 32.6 g (0.30 mol) of trimethylsilyl chloride were added slowly. After stirring for 15 minutes, 90 g THF solution containing 55.4 g (0.30 mol) of 4-t-butoxychlorobenzene and 7.3 g (0.30 mol) of magnesium was slowly added and stirred for 30 minutes. 500 g of 20% aqueous ammonium chloride solution was added to the reaction solution, the organic layer was separated, washed twice with 200 g of water, and the solvent was blown off. The residue was dissolved in 400 ml of ethanol, 300 ml of distilled shoe was added, and the mixture was left at room temperature for 1 day. The resulting solid was filtered and dried to yield the title compound (yield 75%).

Preparation Example B-2: Synthesis of (p-t-butoxyphenyl) diphenylsulfonium nonaplate {nonaflate (p-tert-butoxyphenyl) diphenylsulfonium nonaflate}

To the reactor, 20 ml of DMSO and 0.01 mol (3.845 g) of (pt-butoxyphenyl) diphenylsulfonium chloride obtained from Preparation Example B-1 were added to 0.1 L of an aqueous 0 ° C. solution containing 0.01 mol of sodium nonaplate. And left for two days. The wet cake obtained by filtration was dissolved in 25 ml of methanol, and then the same volume of ethyl ether as methanol was added thereto, and left for 1 day to recrystallize. The resulting crystals were recovered by filtration and then vacuum dried for 24 hours to give the title compound (yield 60%).

Preparation Example B-3: Synthesis of (p-t-butoxycarbonylmethoxyphenyl) diphenylsulfonium nonaplate {(p-tert-butoxycarbonylmethoxyphenyl) diphenylsulfonium nonaflate}

500 g of 48.4 g (0.1 mol) and 1.5 g (0.01 mol) of trifluoromethanesulfonic acid dissolved in the (pt-butoxyphenyl) diphenylsulfonium nona plate obtained from Preparation Example B-2 was dissolved. The methanol solution of was stirred at 70 ° C. for 6 hours. The solvent was removed in vacuo and the remaining solid was washed twice with diethyl ether. 40 g of washed solid material, 20.7 g (0.15 mol) of anhydrous potassium carbonate, and 18.1 g (0.12 mol) of t-butyl chloroacetate were dissolved in 400 g of acetone, followed by 3 hours at 60 ° C. Stirred. Thereafter, the solution was cooled to room temperature, the inorganics were filtered off, and the solvent was removed in vacuo from the filtrate. The solid material thus obtained was separated by silica gel chromatography using a chloroform / methanol (10: 1) mixed solution to obtain the title compound (yield 80%).

Preparation Example C: Resin Synthesis

Preparation Example C-1 Synthesis of p- (t-butoxycarbonyloxy) styrene / p-hydroxystyrene copolymer {p- (t-butoxycarbonyloxy) styrene / p-hydroxystyrene copolymer}

110 g of polyhydroxystyrene (Mw = 11,000) was dissolved in 300 g of acetone and 0.1 g of dimethylamino pyridine was added. After stirring for about 10 minutes, 14 g of di-t-butyldicarbonate was added and reacted for 12 hours. After completion of the reaction, the solid solution produced when the reaction solution was poured into 3 L of distilled water was filtered and dried to obtain the title polymer.

Preparation Example C-2: p- (1-ethyloxyethoxy) styrene / p- (t-butoxycarbonyloxy) styrene / p-hydroxystyrene terpolymer {p- (1-ethyloxyethoxy) styrene / p- Synthesis of (t-butoxycarbonyloxy) styrene / p-hydroxystyrene terpolymer}

700 mL of PGMEA (propyleneglycolmethyletheracetate) was added to a reactor containing 130 g of p- (t-butoxycarbonyloxy) styrene / p-hydroxystyrene copolymer prepared in Preparation Example C-1 for 5-6 hours at room temperature. The mixture was stirred and dissolved, and 25.0 g of ethyl vinyl ether and 25.0 g of PGMEA were mixed and added thereto, followed by stirring for 20 minutes. To the solution, a solution in which 0.97 g of p-TsOH (solid) was dissolved in 30 ml of PGMEA was added and reacted for 2 hours. After the reaction was completed, 1.3 g of NMP (1-methyl-2-pyrrolidinone) was added to 40 g of PGMEA, and the mixture was stirred for about 10 minutes, followed by primary precipitation in about 80 L of water at room temperature, followed by filtration. It was dissolved again in 3.5 L and the solution was second precipitated in 60 L of water, and the resulting solid was vacuum dried to give the title polymer. ^{By 1} H-NMR analysis, the substitution rate was p- (1-ethyloxyethoxy) styrene / p- (t-butoxycarbonyloxy) styrene / p-hydroxystyrene (26.3% / 7.0% / 66.7%) It was confirmed to be.

Example 1: Photoresist Composition Preparation and Pattern Formation

Di (4-vinyloxyethoxyphenyl) -2,6-dimethyl-4-methoxyphenylsulfonium nona plate prepared in Preparation Example A-3, prepared in Preparation Example B-3 (pt-butoxy Carbonylmethoxyphenyl) diphenylsulfonium nonaplate, and p- (1-ethyloxyethoxy) styrene / p- (t-butoxycarbonyloxy) styrene / p- prepared in Preparation Example C-2. A photoresist composition was prepared according to the composition shown in Table 1 using a hydroxystyrene terpolymer.

Each photoresist composition was sprinkled onto a silicon wafer, spin coated at 2300 rpm and then heated at 100 ° C. for 90 seconds to form a 0.5 μm thick film. The film was exposed using a light source of 248 nm wavelength (NA 0.45, Nikon, Japan), and heated at 100 ° C. for 90 seconds (PEB: post exposure bake). Each specimen prepared as described above was evaluated for the characteristics of the Line & Space pattern formed when developed in a TMAH aqueous solution (2.38wt%) for 90 seconds at 23 ℃ and the results are summarized in Table 2 below.

Composition Compound A-3 (mg) Compound B-3 (mg) Resin C-2 (g) Base ¹⁾ (mg) Solvent ²⁾ (g) a 50 250 10.00 30 40 b 90 210 " 30 " c 130 170 " 30 " d 170 130 " 30 " e 210 90 " 30 " f 250 50 " 30 " g 30 70 " 20 " h 60 140 " 12 " i 90 210 " 10 " j 120 280 " 8 " k 150 350 " 6 "

¹⁾ Triisobutylamine

²⁾ Propylene Glycol Methyl Ether Acetate

Composition resolution Remarks a 0.24 nm b 0.22 nm cubic square c 0.22 nm d 0.24 nm e 0.24 nm f 0.24 nm g 0.24 nm h 0.22 nm i 0.22 nm cubic square j 0.22 nm cubic squareroughness best k 0.24 nm

As described in detail above, by using the photoresist composition of the present invention, it is possible to easily form a pattern having excellent resolution.

Claims (3)

(1) a polyhydroxystyrene resin having a structure of formula (1), (2) a crosslinking photosensitive agent having a structure of formula (2), (3) a noncrosslinking photosensitive agent having a structure of formula (3), (4) an organic base And (5) a photoresist composition comprising an organic solvent: [Formula 1] Wherein l, m and n are respectively 0.62 ≦ l / (l + m + n) ≦ 0.8, 0.04 ≦ m / (l + m + n) ≦ 0.06 and 0.16 ≦ n / (l + m + n) Is a real number satisfying ≤0.32) [Formula 2] [Formula 3] The method of claim 1, wherein 100 parts by weight of the polyhydroxy styrene resin, 0.5 to 6 parts by weight of a 1:10 to 10: 1 (w / w) mixture of the cross-linking photosensitive agent and the non-crosslinking photosensitive agent, 0.01 to 0.01 of the organic base 10 parts by weight, and the photoresist composition comprising 250 to 1000 parts by weight of the organic solvent. The photoresist composition of claim 1, further comprising bis (cyclohexylsulfonyl) diazomethane as a photosensitizer.