JP3241757B2 - Resist material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to a lithographic printing method.
cess), especially lithographic printing for device fabrication.

2. Description of the Related Art A lithographic printing method is generally used for manufacturing a device such as a semiconductor device. Of the available lithographic printing methods, photolithographic printing is often used. Photolithographic printing has the advantage of being suitable for full-surface exposure techniques. That is, a material having sensitivity to exposure light is applied on a substrate to be processed, for example, a silicon wafer, to form a plurality of devices. Next, the coating material, that is, the resist is exposed to light through a mask material,
Light that reaches the resist corresponds to the desired pattern to be transferred to the underlying substrate. This method is considered a full-surface exposure, since the exposure is performed simultaneously on an entire device, or on a number of devices, to be processed on a substrate, for example a silicon substrate.

[0003] The full exposure operation is advantageous because it is relatively fast compared to other methods such as raster scanning techniques commonly used when the energy used to expose the resist is an electron beam. However, in general, the resolution obtained by full-surface exposure with ultraviolet or visible light is slightly lower than the resolution obtained by other methods such as electronic lithographic printing. The overall exposure resolution can be improved by using deep ultraviolet light. One way to obtain a deep ultraviolet radiation sensitive photoresist is to use a compound that produces an acid moiety upon such radiation, together with a polymer that reacts with the generated acid. Typical combinations of acid-generating compounds and acid-sensitive polymers include onium salts as photosensitive acid generators and poly (pt-butoxycarbonyl) as polymers having reactive substituents. (Oxystyrene).

It is less desirable to use inorganic salts such as onium salts as acid generators. This is because the inorganic ionic substance generated from the salt may contaminate the device being processed. In addition, ionic acid generators also tend to phase separate from acid sensitive resins.
Therefore, an organic acid generator having an appropriate sensitivity to deep ultraviolet rays used for a photoresist is extremely preferable.

[0005] By using an acid-sensitive polymer in combination with an organic acid generator having a nitrobenzyl structure, very good sensitivity to deep ultraviolet exposure can be obtained. In particular, the expression

Embedded image Where R is not important and R 'is a substituent having a suitable combination of steric and electron withdrawing properties, provided that R is not acidic and does not absorb ultraviolet light to substantially impair sensitivity. ) Is an acid generator. Examples of the substituent R ′ include perfluorinated alkyl, lower alkyl (provided that they are not acids or substantially absorb UV rays), —OR,

Embedded image Or CN, examples of the substituent Y are alkyl such as methyl, substituted alkyl such as trifluoroethyl, aryl such as phenyl, or

Embedded image Wherein R ″ is, for example, lower alkyl and R ″ ″ is

Embedded image It is. The portion used for Y is not particularly critical, but requires a temperature of at least 75 ° C. to split the Y portion from the rest of the acid generator. Since these materials are not ionic, the tendency to phase separate between the polymer and the acid generator is significantly reduced. For the same reason, the possibility of contaminating the underlying substrate is also eliminated. The sensitivity of the resist according to the present invention is good, being as high as ² mJ / cm ² . Therefore, excellent photosensitivity is obtained.

The photosensitive acid generators according to the present invention are particularly useful for photolithographic printing, but are also sensitive to electron and X-rays. Therefore, exposure by these sources is not excluded from the present invention.

Typical acid-sensitive polymers having one acid-reactive substituent per monomer unit include 0.5 to
An acid generator concentration of 50% by weight, preferably 1-20% by weight, is desirable. Concentrations of less than 0.5% by weight of the photosensitive acid generator are not excluded, although resolution and sensitivity are impaired, but are undesirable. Concentrations above 50% by weight are also undesirable, as the quality of the image tends to degrade due to excessive acid generation.

[0008] As mentioned earlier, this photoresist has the formula

Embedded image Where R is not acidic and does not absorb ultraviolet light to substantially impair sensitivity, R is not important, and R 'is steric and electron withdrawing. It is a substituent having an appropriate combination. Substituent R '
Examples of are: perfluorinated alkyl, lower alkyl (having up to 6 carbon atoms), provided that they are not acids or substantially absorb UV light,-
OR, CN or

Embedded image And examples of the substituent Y include alkyl such as methyl,
Substituted alkyl such as trifluoroethyl, aryl such as phenyl, or

Embedded image Wherein R ″ is, for example, lower alkyl and R ″ ″ is

Embedded image It is.

Such a molecule can be further substituted on an aromatic ring. However, acidic substituents should be avoided because the polymer tends to degrade before use. A particularly effective material is bis (2-bis), which combines high acidity and high thermal stability (203 ° C) after irradiation.
(Trifluoromethyl) -6-nitrobenzyl) -1,
3-benzenedisulfonate.

[0010] The sensitivity of the resist material can be essentially increased by appropriate selection of some of R 'and Y. That is, the relative sensitivity to a substance having R ′ as NO ₂ is determined by selecting a substituent having an excessive combination of stericity and electron withdrawing property.
Can be higher. Higher thermal stability allows for post-exposure baking at higher temperatures, while higher temperatures increase the reactivity of the acid with the polymer, and thus increase the sensitivity. In general, it is desirable to obtain maximum thermal stability and maximum sensitivity.

Two factors affect the temperature at which the acid generator decomposes. These factors include steric hindrance by the substituent and the degree of electron withdrawing of the substituent. These two properties are correlated. In general, it is desirable to have a substituent that gives a large steric hindrance in the plane of the molecule and substantially gives an electron withdrawing property. The greater the steric hindrance of the molecule, the less electron withdrawing properties need to be to improve the thermal stability to the dinitrobenzyl compound. Similarly, to obtain the same result as the electron withdrawing property becomes larger,
There is a need for less stereoscopic effects. The factor used to measure steric hindrance is E _s (calculated). This is C.I. Hansch and A.S. Leo, "Substituent constants for correlation analysis in chemistry and biology", calculated using Charton steric parameters as summarized in Wheelie Interscience (1979). It is a Taft stereo parameter, and the linear correlation between the Charton stereo parameter and the experimental Taft stereo parameter is also summarized in Hansch and Leo (see above). Electronic factors were measured in two ways. First, for portions where no adjacent ortho substituent is present, see Hansch and Leo (see above).
The usual sigma values were used, as reported in the literature. Second, the portion where adjacent ortho substituents are present is described in Sigma, as described in Taft's "Steric Effects in Organic Chemistry", edited by Melvin Newman, Willie & Son, p. 595 (1956). Value (σ ')
The inducing component of is used. From FIG. 1, the decomposition temperatures of various compounds (measured by the differential scanning calorimetry exothermic minimum value) are plotted against the sum of E _s (calculated) and σ ′ for the substituent at the ortho position relative to the benzyl addition position. , Or simply plotting against σ of a derivative with a para or meta substitution pattern, gives a linear relationship.

The attraction characteristics of the substituent Y also have a certain effect on thermal stability. As shown in FIG. 2, the greater the induction effect of the substituent Y, the lower the thermal stability. (Σ 'is also a measure of the inductive effect) The steric effect of this substituent is generally not significant, since the substituent Y is relatively far away from the reaction site leading to the generation of the acid. FIG. 2 shows that the decomposition temperature of various dinitrobenzylsulfonic acid esters was σ or σ ′.
When plotted against (when the substituent is ortho to the sulfonyl addition position) a linear relationship is obtained. The resist material using the acid generator according to the present invention is incorporated herein by reference and used as described in the pending U.S. Patent Application No. 316,051, filed February 24, 1989. After the pattern is drawn on the resist, the underlying substrate is M. Morea
u) Processed by techniques generally described in "Semiconductor Lithography", Plenum Press, New York, New York, Chapters 12 and 13. For example, patterned resists are useful as masks for etching, depositing, or implanting ions.

The following examples illustrate the preferred method of preparing the acid generator according to the present invention and the method of using a photoresist. Example 1 Synthesis of 2- (trifluoromethyl) -6-nitrobenzyl bromide 250 ml of carbon tetrachloride, 1 in a 500 ml round bottom flask
5.90 g of 2- (trifluoromethyl) -6-nitrotoluene, 27.60 g of N-bromosuccinimide,
And 11.8 g of benzoyl peroxide. The mixture was refluxed and stirred at this temperature for 14 hours. The mixture was cooled and filtered, and to the filtrate was added 9.94 g of N-bromosuccinimide and 4.2 g of benzoyl peroxide. The mixture was refluxed for 14 hours. The mixture was cooled, filtered, and the solvent was removed from the filtrate. This crude product is
19.57 g after chromatography on a SiO ₂ column.
(88.9% yield) pure product was obtained.

Example 2 Synthesis of silver salt of 1,3-benzenedisulfonic acid 20 ml of distilled water and 5.00 in a 50 ml round bottom flask
g of 1,3-benzenesulfonyl chloride. This suspension was stirred under reflux for 4 hours to obtain a clear solution. The mixture was heated under vacuum to remove most of the water and all of the hydrochloric acid. The crude acid was then added to 5
It was redissolved in 0 ml of distilled water, and 5.30 g of silver carbonate was gradually added. (Bubbling was stopped by adding the last few aliquots.) The aqueous solution was filtered to remove excess silver carbonate. The solution Water was removed under vacuum from grinding a white crystalline solid obtained in the presence of P ₂ 0 _5, and dried overnight under high vacuum. In this way, 8.1 g of silver salt was obtained (93% yield).

Example 3 Synthesis of bis (2- (trifluoromethyl-6-nitrobenzyl) -1,3-benzenedisulfonate In a 50 ml round bottom flask, 10.00 g of 2- (trifluoromethyl) -6 was added. 2 including -nitrobenzyl bromide
7.94 g of silver salt of 1,3-benzenedisulfonic acid suspended in 0 ml of dry acetonitrile were charged. The reaction mixture was heated at reflux under argon for 24 hours. The reaction mixture was filtered to remove AgBr. The solvent was removed from the filtrate, redissolved in 20 ml of chloroform, filtered and the solvent was removed from the resulting filtrate. The crude product was chromatographed on SiO ₂ using methylene chloride to give the purified product, which was then recrystallized from pentane / methylene chloride to give 3.90 g of white crystals (58
%yield).

Example 4 Synthesis of 2- (trifluoromethyl) -6-nitrobenzyl tosylate In a 200 ml round bottom flask, under argon, 22.21
g of 2- (trifluoromethyl) -6-nitrobenzyl bromide, 26.20 g of silver tosylate, and 100
ml of dry acetonitrile was charged. The reaction mixture was stirred under reflux for 7 hours. The mixture was filtered to remove AgBr, the solvent was removed, redissolved in chloroform, and filtered again to remove some of the solvent. Pentane was gradually added to the concentrated solution to cause recrystallization. The material was recrystallized once more from methylene chloride / pentane to give 21.86 g (7.
Pure product (5.0% yield) was obtained.

Example 5 Synthesis of 2- (trifluoromethyl) -6-nitrobenzyl iodide In a 200 ml round bottom flask, 35.08 g of 2- (trifluoro) dissolved in 100 ml of dry acetone in dry nitrogen. Methyl) -6-nitrobenzyl tosylate. To this, with cooling, 28.06 g of anhydrous sodium iodide dissolved in 75 ml of dry acetone was slowly added. The reaction mixture was stirred overnight at room temperature. The acetone was removed from the mixture under vacuum and the residue was redissolved in methylene chloride and filtered. The filtrate was extracted with 50 ml of distilled water, dried over anhydrous magnesium sulfate, filtered and the solvent was removed under vacuum. This resulted in 29.92 g (97% yield) of the product.

Example 6 Synthesis of tris (2- (trifluoromethyl) -6-nitrobenzyl) -1,3,5-benzenetrisulfonate Dissolved in 20 ml of dry acetonitrile in a 50 ml round bottom flask in argon under argon. 3.00 g of silver 1,3,5-benzenetrisulfonate was added. And 4.66g
2- (trifluoromethyl) -6-nitrobenzyl iodide was added and the reaction mixture was refluxed for 12 hours. The mixture was filtered to remove AgI and the solvent was removed under vacuum.
The residue was redissolved in chloroform, filtered, and recrystallized by adding carbon tetrachloride. This crude crystal was treated with methylene chloride /
Recrystallization from pentane gave 1.44 g of the product (3
3% yield).

Example 7 Synthesis of 2,2'-dimethyl-3,3'-dinitrobiphenyl In a 20 ml round bottom flask equipped with a reflux column, under argon, 7.05 g of 2-iodo-6-nitrotoluene and 6 .55 g of copper bronze were charged. The reaction mixture was heated in an oil bath at 230 ° C. for 9 hours. The mixture was extracted with methylene chloride and the extract was filtered. The solvent was removed from the extract and chromatographed on silica gel using carbon tetrachloride as eluent. In this way, 1.71 g (65% yield) of yellow crystals were obtained.

Example 8 Synthesis of 2,2'-di (bromomethyl) -3,3'-dinitrobiphenyl In a 100 ml round bottom three-necked flask equipped with a reflux column and a dropping funnel, 0.24 g of benzoyl peroxide and 40 ml 1.49 g of 2,2'- dissolved in carbon tetrachloride
Dimethyl-3,3'-dinitrobiphenyl was charged. The mixture was refluxed and 1.75 g of bromide dissolved in 10 ml of carbon tetrachloride were added dropwise. While adding
The reaction flask was irradiated with a 275 WW sunlamp (GE). After addition of the bromide, the mixture was irradiated under reflux for 2 days. The solvent was removed from the reaction mixture, the residue was redissolved in hot chloroform, filtered and the solvent was removed under vacuum. The crude product was chromatographed on silica gel using methylene chloride as eluent. In this way, 1.42 g (60% yield) of tan crystals were obtained.

Example 9 Synthesis of 2,2 '-(tosyloxymethyl) -3,3'-dinitrobiphenyl In a 20 ml flask, under argon, 1.20 g of 2,2
2'-Di (bromomethyl) -3,3'-dinitrobiphenyl and 1.87 g of silver tosylate dissolved in 10 ml of dry acetonitrile were charged. The mixture was refluxed for 5 hours. The mixture was filtered to remove AgBr, the solvent was removed, redissolved in chloroform, filtered, and finally the solvent was removed again. The crude product is chromatographed on silica gel using methylene chloride as eluent and the product recrystallized from pentane / methylene chloride to give 1.24 g (77% yield) of white crystals. Was.

Example 10 Synthesis of 2-methyl-6-nitrobenzyl alcohol Into a 100 ml round bottom flask was placed 60 ml of dry argon in dry argon.
5 g of 2-methyl-6-nitrobenzoic acid, dissolved in dry tetrahydrofuran, was added. To this solution is added, with cooling and stirring, a 6M 1M solution of BH ₃ .THF in THF 64.1.
7 ml was added slowly. The mixture was refluxed for 17 hours,
The reaction was then slowly and carefully cooled with excess 10% aqueous hydrochloric acid. The THF was removed under vacuum and the residue was extracted with 50 ml each time of methylene chloride. The combined organic extracts were dried over anhydrous magnesium sulfate, filtered, and the solvent was removed. The crude product was recrystallized from methylene chloride / pentane to give 4.95 g (97% yield) of yellow crystals.

Example 11 Synthesis of 2-methyl-6-nitrobenzyl tosylate In a 100 ml round bottom flask equipped with a dropping funnel, under argon, 2.50 g of 2-methyl-6-nitrobenzyl alcohol, and 30 ml 2. dissolved in dry acetone
14 g of tosyl chloride were charged. The mixture is heated to a temperature of 1
While cooling below 5 ° C., 3.30 ml of dicyclohexylamine dissolved in 5 ml of dry acetone were added dropwise. The reaction mixture was returned to room temperature and stirred for one day. The mixture was filtered to remove dicyclohexylamine hydrochloride, the solvent was removed in vacuo, and the residue was chromatographed on silica gel using carbon tetrachloride as eluent. The product was recrystallized from methylene chloride / pentane to give 1.82 g (38% yield) of white crystals.

Example 12 Synthesis of 2-phenyl-6-nitrotoluene In a 100 ml round bottom flask, under argon, 480 mg of tetrakis (triphenylphosphine) palladium (0) and 3 dissolved in 50 ml of degassed toluene.
g of 2-bromo-6-nitrotoluene was charged. To this was added, under argon, 9 ml of a 2 M aqueous solution of degassed Na ₂ CO ₃ and 1.7 g of phenylboronic acid dissolved in 20 ml of ethanol. The mixture was refluxed for 6 hours with stirring. Treated with 30% H ₂ O ₂ for 1 hour to remove residual boronic acid. The mixture was extracted with methylene chloride, washed with saturated saline, and the combined organic extracts were dried over anhydrous magnesium sulfate, filtered, and the solvent was removed. The residue was chromatographed on silica gel using methylene chloride as eluent to yield 1.78 g (60% yield).
Brown crystals were obtained.

Example 13 Synthesis of 2-phenyl-6-nitrobenzyl bromide The starting material is a reaction of 2 g of 2-phenyl-6-nitrotoluene with 1.5 g of bromine and 0.110 g of benzoyl peroxide. Otherwise, the procedure of Example 8 was used. In this way, 2 g (77% yield) of yellow crystals were obtained.

Example 14 Synthesis of 2-phenyl-6-nitrobenzyl tosylate Except that the starting material was obtained by reacting 1.50 g of 2-phenyl-6-nitrobenzyl bromide with 1.86 g of silver tosylate. The procedure of Example 4 was used. In this way, 1.5 g (79% yield) of yellow crystals were obtained.

Example 15 Synthesis of 2- (3-nitrophenyl) -6-nitrotoluene The starting material was 1.3 g of 2-nitrophenylboronic acid.
g of 2-bromo-6-nitrotoluene and 0.480
The procedure of Example 12 was used except that it was reacted with g of tetrakis (triphenylphosphine) palladium (0). In this way, 2.8 g (79% yield)
Was obtained as yellow crystals.

Example 16 Synthesis of 2- (3-nitrophenyl) -6-nitrobenzyl bromide Starting material was 0.80 g of 2- (3-nitrophenyl)-
The procedure of Example 8 was used except that 6-nitrotoluene was reacted with 0.49 g of bromine and 33 mg of benzoyl peroxide. Thus, 0.80 g (7
(7% yield) yellow crystals were obtained.

Example 17 Synthesis of 2- (3-nitrophenyl) -6-nitrobenzyl tosylate Starting material is 1.17 g of 2- (3-nitrophenyl)-
The procedure of Example 4 was used except that 6-nitrobenzyl bromide was reacted with 1.02 g of silver tosylate. In this way, 0.60 g (40% yield) of yellow crystals were obtained.

Example 18 Synthesis of silver tresylate The procedure of Example 2 was used except that the starting material was using 4.30 ml of 2,2,2-trifluoroethanesulfonyl chloride. The crude acid was reacted with 10 g of silver carbonate and after treatment, 10.63 g (99% yield) of silver tresylate was obtained.

Example 19 Synthesis of 2- (trifluoromethyl) -6-nitrobenzyltresylate The starting material was 2.20 g of silver tosylate and 3.00 g of 2
The procedure of Example 3 was used except that it was reacted with-(trifluoromethyl) -6-nitrobenzyl bromide. After refluxing for 48 hours, after the treatment, 1.43 g (34%
Yield) white crystals were obtained.

Reference Example 1 Synthesis of 2-nitro-5- (trifluoromethyl) benzyl bromide Using 4.00 g of 2-nitro-5- (trifluoromethyl) toluene as a starting material, adding two reagents The procedure of Example 1 was used except that only 1.18 g of each benzoyl peroxide was used. In this way, 3.
09 g (54% yield) of a yellow oil was obtained.

Reference Example 2 Synthesis of 2 -nitro-5- (trifluoromethyl) benzyl tosylate The procedure of Example 2 was repeated except that 2.00 g of 2-nitro-5- (trifluoromethyl) benzyl bromide was used as a starting material. Procedure 4 was used. 1.61 g in this way
(61% yield) white crystals were obtained.

Reference Example 3 Synthesis of 2-nitro-6-fluorobenzyl bromide The procedure of Reference Example 1 was used, except that 10.0 g of 2-nitro-6-fluorotoluene was used as a starting material. In this way, 6.70 g (44% yield) of white crystals were obtained.

Reference Example 4 Synthesis of 2-nitro-6-fluorobenzyl tosylate The procedure of Example 4 was used except that 3.00 g of 2-nitro-6-fluorobenzyl tosylate was used as the starting material. Thus, 3.60 g (86% yield)
Was obtained as white crystals.

Reference Example 5 Synthesis of 2-nitro-6-bromobenzyl bromide The procedure of Reference Example 1 was used, except that 10.0 g of 2-nitro-6-bromotoluene was used as a starting material.
In this way, 13.3 g (97% yield) of white crystals were obtained.

Reference Example 6 Synthesis of 2-nitro-6-bromobenzyl tosylate The procedure of Example 4 was used except that 3.00 g of 2-nitro-6-bromobenzyl bromide was used as the starting material. In this way, 1.50 g (38% yield) of yellow crystals were obtained.

Reference Example 7 Synthesis of 2-nitro-4- (trifluoromethyl) benzyl alcohol 1.00 g of 2-nitro-4- (trifluoromethyl) toluic acid was used as a starting material in 1M BH ₃ .THF THF.
The procedure of Example 10 was used except that it was reacted with 9.0 ml of solution. After silica gel chromatography with methylene chloride in this way, 0.80 g (82% yield) of white crystals were obtained.

Reference Example 8 Synthesis of 2-nitro-4- (trifluoromethyl) benzyl tosylate The procedure of Example 1 was repeated except that 3.50 g of 2-nitro-4- (trifluoromethyl) benzyl bromide was used as a starting material. Eleven procedures were used. In this way, after processing
3.25 g (65% yield) of white crystals were obtained.

Reference Example 9 Synthesis of 2,6-dinitrobenzyl-4- (trifluoromethyl) benzenesulfonate 2.00 g of 2,6-dinitrobenzyl alcohol,
The procedure of Example 11 was used except that 2.71 g of 4- (trifluoromethyl) benzenesulfonyl chloride and 2.2 ml of dicyclohexylamine were used.
The crude product was recrystallized using carbon tetrachloride / chloroform to give 1.55 g (38% yield) of white crystals. Further, the compounds shown in Table 1 were prepared. Table 1 Synthetic data of 2-nitrobenzylsulfonic acid ester derivatives Compound ^a R _a R _b Yield% synthetic methods ^d 6-NO ₂ 9-CF ₃ 48 Example 11 RT = 3h 6-NO ₂ 10-CF ₃ 69 Example 11 RT = 2h 6-NO ₂ 11-CF ₃ 38 Example 11 RT = 17h 6-NO ₂ 11 -F 62 example _{11 RT = 17h 6-NO 2} 9,11- di F 58 example _{11 RT = 4h 6-NO 2} 10-SO 3 R b 50 example 11 RT = 4h 6-NO ₂ tresyl ^c 52 Example 3 RT = 48 6-NO ₂ 2-NO ₂ 66 Example 11 RT = 4h 6-CF ₃ 11-CH ₃ 80 Example 3 RT = 17h Reflux 5-CF ₃ 11-CH ₃ 61 Example 3 RT _{= 17h 4-CF 3 11-} CH 3 65 example 11 RT = 17h 6-CF ₃ tresyl ^c 34 example ₃ RT = 48 6-CF 3 penta -F 14 example 3 RT = 48 reflux 6-F 11- CH ₃ 86 example 3 RT = 17h 6-Br 11 -CH 3 38 example 3 RT = 17h a) the structure see FIG. 3 b) R = 2,6 esters dinitrobenzyl c) Toreshikku acid d) RT = Reaction time

Lithographic Printing (Lithography) Example 20 The material of Example 3 was evaluated for lithographic printing characteristics. 23
To 8 mg of bis (2-trifluoromethyl-6-nitrobenzyl) -1,3-benzenedisulfonate was added 1.5 g of poly (t-butoxycarbonyloxystyrene-sulfone). This mixture was dissolved in 15 ml of cyclohexanone. The resulting solutions were each placed from top to bottom, 1.
Teflon with porosity of 0, 0.5 and 0.2 μm
Filtered through a stack of ^TM filter discs. Approximately 2 ml of the filtrate is applied to a 4-inch silicon wafer (110
(Crystal face) and spin-coated at 2000 rpm. Place this wafer on a hot plate,
Heated to 5 ° C and held at this temperature for 90 seconds. This wafer was transferred to Carl Zeus Incorporated, Model M
Placed on A56A contact aligner sample holder. The aligner is fitted with a lambda physics excimer laser operating at 248 nm. 2 μm
Exposure was performed through a mask having a series of lines and spaces ranging from .about.0.5 .mu.m. Exposure was performed at 7.5 mJ / cm ² . The wafer was heated to 135 ° C. on a hot plate and kept at this temperature for 1 minute. The wafer is placed in an approximately 0.18N aqueous solution of tetramethylammonium hydroxide for 30 minutes.
Soaked for seconds. The developed resist exhibited the desired resolution down to the mask resolution limit of 0.5 μm.

Example 21 Bis (2- (trifluoromethyl) -6-nitrobenzyl) -1,3-benzenedisulfonate was replaced with 18
The procedure of Example 20 was followed except that 3 mg of 2-nitro-6-methylbenzyl tosylate was used. In addition, printing before exposure was performed at 115 ° C. for 2 minutes, and printing after exposure was performed at 115 ° C. for 1 minute. Exposure was performed through a mask that provided different doses at various portions of the coated resist. The resulting exposure is 45 mJ / cm, the minimum exposure required to obtain a completely removed exposure area after development.
^The measurement showed a sensitivity of ² .

Example 22 The procedure of Example 30 was followed except that 200 mg of 2-nitro-6-phenylbenzyl tosylate was used instead of 2-nitro-6-methylbenzyl tosylate. The sensitivity was about 60 mJ / cm ² .

Example 23 Instead of 2-nitro-6-methylbenzyl tosylate,
The procedure of Example 30 was followed except that 223 mg of 2-nitro-6- (nitrophenyl) benzyl tosylate was used. The sensitivity was 90 mJ / cm ² .

Example 24 Instead of 2-nitro-6-methylbenzyl tosylate,
The procedure of Example 21 was followed except that 319 mg of 2-nitrodiphenylbenzyl tosylate was used. The obtained sensitivity was 62 mJ / cm ² . Table 2 shows the lithographic print data. In each case, the solution used 8 mol% of poly (t-butoxycarbonyloxystyrene-sulfone) and substituted nitrobenzyl esters (based on the number of t-butoxycarbonyloxy adducts in the polymer) and cyclohexanone as solvent. Prepared. Pre-exposure baking was performed at 115 ° C. for 2 minutes, and post-exposure baking was performed at 115 ° C. for 1 minute. In addition, exposure was performed through a mask that provided different doses at various portions of the coated resist. The exposed wafer was immersed in isopropyl alcohol for 30 seconds. The sensitivity shown in Table 2 is the minimum exposure required to obtain a completely removed exposure area after development.

[0046] Table 2 Lithographic printing properties the compounds of the 2-nitrobenzyl sulfonate derivatives _^a R ^a R _b Sensitivity Contrast _{^{mJ / cm 2 6-NO 2}} 9-CF 3 8> 10 6-NO 2 10-CF 3 10 > 10 6-NO ₂ 11-CF ₃ 13 10 6-NO ₂ 11-F 18 15 6-NO ₂ 9,11-di F 14 9 6-NO ₂ 10-SO ₃ R ^b 8 4 6-NO ₂ 9 -NO ₂ 17 8 6-CF ₃ 11-CH ₃ 43 10 4-CF ₃ 11-CH ₃ 106 5 5-CF ₃ 11-CH ₃ 65 9 6-CF ₃ Tresyl ^c 15 5 6-F 11-CH ₃ 72 5 6-Br 11-CH 3 72 6 6-NO 2 11-NO 2 17 4 6-NO 2 11-CH 3 25> 10 a) R a, see Figure 3 for the location of R _b. b) R = 2,6-dinitrobenzyl c) ester of tresic acid

[Brief description of the drawings]

FIG. 1 shows the relationship between the decomposition temperature and the sum of σ ′ and E _S for various compounds.

FIG. 2 shows the relationship between the decomposition temperature and the sum of σ ′ for various compounds.

FIG. 3 shows a structure derived from 2-nitrobenzylsulfonic acid ester.

Continued on the front page (72) Inventor Thomas Kisavier Noonan United States 07974 New Jersey, New Providence, Springfield Avenue 1200 (72) Inventor Elsa Reich Manis United States 07090 New Jersey, Westfield, Saint Marks Avenue 550 (56) Reference Document JP-A-63-26653 (JP, A) JP-A-2-6958 (JP, A) JP-A-3-223862 (JP, A) JP-A-4-211258 (JP, A) JP-A-3-3 223861 (JP, A) JP-A-3-223857 (JP, A) JP-A-2-248952 (JP, A) JP-A-2-248953 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) G03F ^7/ 00-7/42

Claims (3)

(57) [Claims] 1. A method of fabricating a device comprising the steps of: forming a radiation sensitive region on a substrate, patterning the region, using the patterned region as a mask, and further processing the device. The region is 1) a substance that reacts in response to an acidic moiety and 2) a compound of the formula [ Wherein , R ′ is a perfluorinated alkyl, a lower alkyl,
Coxide, cyano, or Is selected from the group consisting of:
Kill, aryl or substitution not containing NO ₂ as a substituent
Is an aryl (R is not acidic, does not substantially absorb ultraviolet light, and R 'provides a suitable cube and electron withdrawing property, so that an acid generator with any Y has R' is NO ₂ , R has a higher thermal stability as compared to the acid generator having the same Y when R is hydrogen.)]. 2. The method according to claim 1, wherein said acid generator is bis (2- (trifluoromethyl) -6-nitrobenzyl) 1,3-benzenedisulfonate. 3. The formula: Wherein R ′ is a perfluorinated alkyl, lower alkyl, alkoxide, cyano, or Wherein Y is an alkyl, substituted alkyl, aryl or substituted aryl that does not contain NO ₂ as a substituent.