JP2874579B2 - Sulfonium salt and resist material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to deep ultraviolet rays,
It has high sensitivity to high energy rays such as lines, and can be patterned by developing with an alkaline aqueous solution.
The present invention relates to a novel sulfonium salt suitable as a component of a chemically amplified positive resist material suitable for fine processing technology, and a chemically amplified positive resist material containing the sulfonium salt.

[0002]

2. Description of the Related Art LSI
With the demand for finer pattern rules in line with the higher integration and higher speed of light sources, light exposure, which is currently used as a general-purpose technology, is approaching the intrinsic resolution limit due to the wavelength of the light source. is there. In light exposure using a g-line (436 nm) or an i-line (365 nm) as a light source, a pattern rule of about 0.5 μm is limited, and the integration degree of an LSI manufactured using this is 16 Mbit DR.
AM equivalent. However, LSI prototypes have already been made at this stage, and there is an urgent need to develop further miniaturization techniques.

[0003] Against this background, far-ultraviolet lithography is expected as a next-generation microfabrication technology. This deep ultraviolet lithography is 0.3-0.4μ
m can be processed, and when a resist having low light absorption is used, a pattern having side walls nearly perpendicular to the substrate can be formed. In recent years, attention has been paid to a technique using a high-brightness KrF excimer laser as a light source of far ultraviolet rays, and a resist material having low light absorption and high sensitivity is required to be used as a mass production technique.

A recently developed acid-catalyzed chemically amplified positive resist material (Japanese Patent Publication No. 2-27660,
JP-A-3-27829) is a resist material that has high sensitivity, high resolution, and high dry etching resistance, and has excellent characteristics and is particularly promising for deep ultraviolet lithography.

However, when a conventional chemically amplified positive resist is subjected to deep ultraviolet, electron beam, or X-ray lithography, it is exposed to PEB (Post Exposure).
If the standing time until the Bake is long, the line pattern becomes a T-top shape when the pattern is formed, that is, the pattern upper portion becomes thicker [PED (Po
st Exposure Delay), which is considered to be due to a decrease in the solubility of the resist surface, and is a major drawback in practical use. This makes it difficult to control dimensions in the lithography process,
It also impairs dimensional controllability even when processing a substrate using dry etching [Ref: W.M. Hinsberg,
et al. , J. et al. Photopolym. Sci, T
echnol. , 6 (4), 535-546 (199
3). Kumada, et al. , J. et al. Photo
oppolym. Sci, Technol. , 6 (4),
571-574 (1993)]. There has not yet been a chemically amplified positive resist that solves this problem.

It is believed that the cause of the PED problem in chemically amplified positive resists is largely due to basic compounds in the air. The acid on the resist surface generated by the exposure reacts and deactivates with the basic compound in the air, resulting in PEB
The longer the standing time until, the longer the amount of deactivated acid increases, so that the decomposition of the acid labile group hardly occurs.
Therefore, a hardly-solubilized layer is formed on the surface, and the pattern has a T-top shape.

However, by adding a small amount of a basic compound to the chemically amplified positive resist, the acid concentration distribution at the mask edge can be sharpened even when the optical contrast of the mask pattern is reduced near the resolution limit. It is known that the controllability is improved, and the acid generated by light interference in the mask light-shielding portion is completely neutralized by the basic compound, thereby solving the problem of resist scum (Japanese Patent Laid-Open No. 5-127369). No.).

It is known that the addition of a basic compound can suppress the influence of a basic compound in the air, and thus has an effect also on PED (Japanese Patent Application Laid-Open No. 5-232706; No. 5-249683),
The basic compound used here is not incorporated into the resist film due to volatilization, or has poor compatibility with each component of the resist, and has a problem in reproducibility of the effect because the dispersion is uneven over the width of the resist film. It was found that the resolution was reduced.

The present invention has been made in view of the above circumstances,
The problem of the surface hardly soluble layer that causes the T-top shape, that is, P
It is an object of the present invention to provide a novel sulfonium salt suitable as a component of a chemically amplified positive resist material suitable for a fine processing technique for solving the problem of ED, and a chemically amplified positive resist material containing the sulfonium salt.

[0010]

The present inventors have made intensive studies to achieve the above object, and as a result, for example, have found that a sulfoxide compound represented by the following general formula (3) may be added to trimethylsilyl triflate and the following general formula: By reacting the aryl Grignard reagent represented by (4), a novel sulfonium salt having a nitrogen-containing aromatic group represented by the following general formula (1) can be obtained, and the sulfonium salt is formed into a T-top form. It is suitable as a component of a chemically amplified positive resist material suitable for fine processing technology that solves the problem of the surface hardly soluble layer that is the cause, that is, the problem of PED.
In particular, they have found that they can be very effective in deep ultraviolet lithography.

[0011]

Embedded image (Wherein R ¹ , R ² , and R ³ are selected from a phenyl group, a tert-butoxyphenyl group, or a nitrogen-containing aromatic group;
^At least one of R ¹ , R ² and R ³ is a tert-butoxyphenyl group and at least one is a nitrogen-containing aromatic group, or R ¹ , R ² and R ³ are all a nitrogen-containing aromatic group And the nitrogen-containing aromatic group is a dialkylaminophenyl group having 1 to 8 carbon atoms of an alkyl group, a picolyloxyphenyl group or a pyridinyl group. )

The resist material containing a sulfonium salt represented by the above general formula (1) of the present invention can be obtained by the effect of the nitrogen-containing substituent of the sulfonium salt represented by the above general formula (1), that is, in the air on the resist surface. The effect of the deactivation of the acid by the basic compound can be made very small, so that the formation of a hardly soluble surface layer is suppressed, and the nitrogen-containing substituent, which is a basic group, is a sulfonium salt which is an acid generator. , Good compatibility with resist components,
Since the dispersion in the resist film is uniform, there is no problem in reproducibility of the effect. Further, in the case of having an acid labile group, it is possible to enhance the contrast by the effect of the acid labile group, and to solve the problem of the surface hardly soluble layer which causes the T-top shape, that is, the problem of the PED. An object of the present invention is to provide a novel sulfonium salt suitable as a component of a chemically amplified positive resist material suitable for a fine processing technique to be solved, and a chemically amplified positive resist material containing the sulfonium salt.

Accordingly, the present invention provides a sulfonium salt represented by the above general formula (1) and a chemically amplified positive resist material containing this sulfonium salt.

In this case, as the resist material, (A) an organic solvent (B) an alkali-soluble resin (C) a dissolution inhibitor having an acid labile group (D) a sulfonium salt (E) Onium salts or other acid generators represented by the following general formula (2) (R) _n MY (2) (wherein R represents the same or different unsubstituted or substituted aromatic group; Represents sulfonium or iodonium, Y represents p-toluenesulfonate or trifluoromethanesulfonate, and n represents 2 or 3.), and (A) an organic solvent (B) an alkali-soluble resin (C) A dissolution inhibitor having an acid labile group (D) A resist material containing the above sulfonium salt is effectively used.

Now, the present invention will be described in further detail. The novel sulfonium salt of the present invention has the following general formula (1)
Is a sulfonium salt represented by

[0016]

Embedded image

Here, in the above formula (1), R ¹ , R ² , R
³ is an unsubstituted or substituted aromatic group, and R ¹ , R ² , R ³
At least one of which is a substituted aromatic group having an acid labile group,
Further, at least one of the remaining is a nitrogen-containing aromatic group, or all of R ¹ , R ² , and R ³ are nitrogen-containing aromatic groups. Examples of the unsubstituted aromatic group include a phenyl group. Examples of the substituted aromatic group having an acid labile group include tertiary group.
and a t-butoxyphenyl group. Further, as the nitrogen-containing aromatic group, a dialkylaminophenyl group having 1 to 8 carbon atoms of an alkyl group, a picolyloxyphenyl group, and a pyridinyl group are preferable. Among them, a dimethylaminophenyl group, a diethylaminophenyl group, a picolyloxyphenyl group are preferable. And a pyridinyl group are more preferably used.

Specific examples of the sulfonium salt of the above formula (1) include bis (p-trifluoromethanesulfonic acid).
tert-butoxyphenyl) (p-dimethylaminophenyl) sulfonium, trifluoromethanesulfonic acid (p-tert-butoxyphenyl) bis (p-dimethylaminophenyl) sulfonium, trifluoromethanesulfonic acid bis (p-tert-butoxyphenyl)
(P-picolyloxyphenyl) sulfonium, (p-tert-butoxyphenyl) bis (p-picolyloxyphenyl) sulfonium trifluoromethanesulfonate,
Trifluoromethanesulfonic acid (p-tert-butoxyphenyl) (p-dimethylaminophenyl) phenylsulfonium, trifluoromethanesulfonic acid (pt
tert-butoxyphenyl) (p-picolyloxyphenyl) phenylsulfonium, bis (p-tert-butoxyphenyl) (pyridin-4-yl) sulfonium trifluoromethanesulfonate, bis (p-tert-butoxyphenyl) trifluoromethanesulfonate (Pyridin-3-yl) sulfonium, bis (p-tert-butoxyphenyl) (pyridin-2-yl) sulfonium trifluoromethanesulfonate, tris (4-dimethylaminophenyl) sulfonium trifluoromethanesulfonate and the like can be mentioned.

The sulfonium salt of the formula (1) of the present invention is prepared by reacting a sulfoxide compound represented by the following general formula (3) with trimethylsilyl triflate, and then adding THF (tetrahydrofuran) represented by the following general formula (4). By reacting the prepared aryl Grignard reagent in an organic solvent.

[0020]

Embedded image

In this case, the above reaction is carried out with methylene chloride, TH
It is preferably performed in an organic solvent such as F. When reacting trimethylsilyl triflate with the sulfoxide compound represented by the formula (3), trimethylsilyl triflate is added dropwise at a ratio of 1 to 2 mol to the sulfoxide compound (3), and the sulfoxide compound represented by the formula (3) is added. When R ¹ or R ² has an acid labile group, the reaction is preferably performed in the presence of a base such as triethylamine or pyridine. The reaction conditions are −78 to 0 ° C. and 10 to
Preferably, it is 60 minutes.

Further, when reacting the prepared aryl Grignard reagent (4) in an organic solvent such as THF, -78
It is preferable that the aryl Grignard reagent (4) is added dropwise to the sulfoxide compound (3) at a temperature of ０0 ° C. in a ratio of 1 to 3 mol. The aging condition of the reaction is preferably 0 to 40 ° C. for 0.5 to 2 hours. After completion of the reaction, the desired sulfonium salt of the formula (1) can be obtained by washing and concentrating the solvent layer, followed by recrystallization or column fractionation.

The chemically amplified positive resist composition of the present invention contains a sulfonium salt represented by the above general formula (1), and is composed of a two-component system (alkali-soluble resin / acid generator) or a three-component system (alkali-soluble resin). / Acid generator / dissolution inhibitor) can be used as an acid generator in a chemically amplified positive resist material or added to them. It is preferable to use it by adding it to a three-component chemically amplified positive resist. This resist material is composed of (A)
150 to 700 parts (parts by weight, hereinafter the same) of the organic solvent, preferably 250 to 500 parts, (B) alkali-soluble resin 7
0 to 90 parts, preferably 75 to 85 parts, (C) 0 to 40 parts of a dissolution inhibitor having an acid labile group, preferably 10 to 2 parts.
5 parts, (D) 0.1 to 5 parts, preferably 0.8 to 4 parts, of the sulfonium salt represented by the general formula (1), (E) 0 to 15 parts, preferably 2 to 8 parts of the acid generator Are preferred.

Here, as the organic solvent of the component (A),
Ketones such as cyclohexanone and methyl-2-n-amyl ketone; 3-methoxybutanol; 3-methyl-3
Alcohols such as -methoxycybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether ,
Ethers such as diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, esters such as methyl-3-methoxypropionate and ethyl-3-ethoxypropionate , But may be used alone or in combination of two or more. At this time, 1-ethoxy-2-propanol, which has the highest solubility of the acid generator of the resist component, is preferably used.

Examples of the alkali-soluble resin as the component (B) include polyhydroxystyrene or a derivative thereof. Preferably, polyhydroxystyrene in which the OH group is partially substituted with an acid-labile group is used. In this case, the substituent unstable to an acid includes tert.
-Butyl group, tert-butoxycarbonyl group, tetrahydropyranyl group and the like are preferable, and the degree of substitution is 10 to 50.
Mol%, weight average molecular weight 5,000-100,000
It is preferable that

The dissolution inhibitor of the component (C) has at least one group decomposed by an acid (acid labile group) in the molecule, and may be either a low molecular weight compound or a polymer. Good. As the dissolution inhibitor, known compounds can be used. Examples of the low molecular weight compound include bisphenol A derivatives and carbonate derivatives having an acid labile group.
Compounds substituted with a butoxy group or a butoxycarbonyloxy group are preferred. Examples of polymer dissolution inhibitors include:
Examples include a copolymer of p-butoxystyrene and t-butyl acrylate and a copolymer of p-butoxystyrene and maleic anhydride. In this case, the weight average molecular weight is preferably from 500 to 10,000.

The acid generator (E) includes onium salts, oximesulfonic acid derivatives, 2,6-dinitrobenzylsulfonic acid derivatives, diazonaphthoquinonesulfonic acid ester derivatives, and 2,4-bistrichloromethyl-6-
Aryl-1,3,5-triazine derivative, α, α′-
Examples include bisarylsulfonyldiazomethane derivatives. Preferably, it is an onium salt represented by the following formula (2) (R) _n MY (2).

Here, R is the same or different unsubstituted or substituted aromatic group, for example, phenyl, tert-butoxycarbonyloxyphenyl, tert-butoxyphenyl, tert-butylphenyl, methoxyphenyl, hydroxyphenyl And M is sulfonium or iodonium, and Y is p-toluenesulfonate or trifluoromethanesulfonate. N is 2 or 3.

Specific examples of such onium salts include the following iodonium salts and sulfonium salts.

[0030]

Embedded image

Further, additives such as a surfactant for improving coating properties and a light-absorbing material for reducing the influence of irregular reflection from the substrate can be added to the resist material of the present invention.

The method of using the resist material of the present invention, the method of using light, and the like can be performed by using a known lithography technique.
It is most suitable for fine patterning with 3 nm far ultraviolet light and electron beam.

[0033]

The resist material of the present invention is sensitive to high energy rays, especially KrF excimer laser as a positive resist material, and has excellent sensitivity, resolution, plasma etching resistance and heat resistance of the resist pattern. ing. Further, it is a chemically amplified positive resist material suitable for a microfabrication technique for solving the problem of the surface insoluble layer which is the cause of the T-top shape, that is, the problem of PED. It is effective as a component of a mold resist material.

[0034]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Synthesis Examples of the sulfonium salt of the present invention and Examples of resist materials, but the present invention is not limited to the following Examples.

Synthesis Example 1 Bis (p-tert-butyl trifluoromethanesulfonate )
Toxiphenyl) (p-dimethylaminophenyl) sul
Synthesis of phonium bis (p-tert-butoxyphenyl) sulfoxide 8.5 g (0.025 mol), triethylamine 1.3
g (0.013 mol) in methylene chloride (110 g) was dissolved in a dry ice methanol bath at -70.
After cooling to 6.0 ° C., trimethylsilyl triflate 6.0.
g (0.027 mol) was stirred and added dropwise while controlling the temperature so as not to exceed −60 ° C.

Then, the reaction temperature was adjusted to 0 to 5 ° C. by replacing the dry ice methanol bath with an ice water bath, followed by stirring for 10 minutes.

The obtained reaction solution was cooled again to -70 ° C. using a dry ice methanol bath, and 1.2 g (0.049 mol) of magnesium metal, 18.9 g of tetrahydrofuran and 4-bromo-N, A Grignard reagent prepared by a conventional method using 9.9 g (0.049 mol) of N-dimethylaniline was added dropwise while controlling the reaction temperature not to exceed −60 ° C.

Next, the bath was replaced with an ice water bath again, and the reaction temperature was set to 0 to 0.
The mixture was further stirred for 60 minutes at 5 ° C. to complete the reaction.

After the excess Grignard reagent was decomposed by adding water dropwise to the obtained reaction solution, filtration was performed to remove the generated inorganic salts. The obtained filtrate was washed three times with 130 g of water. The obtained organic layer was dried under reduced pressure to obtain an oily substance. The obtained oil was subjected to silica gel column chromatography to give a yield of 4.8 g (yield 32%) and a purity of 98%.
Of trifluoromethanesulfonic acid bis (p-tert-
(Butoxyphenyl) (p-dimethylaminophenyl) sulfonium was isolated.

The results of nuclear magnetic resonance spectrum (NMR), infrared spectrum (IR), and elemental analysis of the obtained bis (p-tert-butoxyphenyl) (p-dimethylaminophenyl) sulfonium trifluoromethanesulfonate are shown below. Shown below. < ¹ H-NMR: CDCl ₃ , δ (ppm)>

[0041]

Embedded image (A) 1.38 singlet 18H (b) 3.00 singlet 6H (c) 6.76-6.79 doublet 2H (e) 7.11-7.15 doublet 4H (d), (F) 7.40 to 7.45 Multiplet 6H <IR: (cm ⁻¹ )> 3095, 3072, 2980,
2935, 2873, 2827, 1589, 1520,
1489, 1446, 1373, 1308, 1265
1223, 1203, 1157, 1074, 1030,
991,927,892,816 <Elemental _{analysis: (%) C 29 H 36} F 3 NO 5> the theoretical value C: 58.1 H: 6.0 N: 2.3 Found C: 57.8 H: 6.3 N: 2.2

Reference Example Magnesium 24.3 g (1 mol), p-tert-butoxyphenyl chloride 20
A Grignard reagent prepared by a conventional method using 3.2 g (1.1 mol) and 280 g of THF was diluted with 500 g of THF, and cooled to −60 ° C. or lower in a Doyler ice methanol bath. Then, 47.5 g (0.4 mol) of thionyl chloride was added to T
A solution diluted with 70 g of HF was added dropwise over 1 hour at a temperature not exceeding 0 ° C. After aging for 1 hour in an ice bath, 36 g of water was added to decompose excess Grignard reagent. 400 g of a saturated aqueous solution of ammonium chloride and 300 g of water were further added to 1000 g of methylene chloride to carry out liquid separation, and the organic solvent layer was washed twice with 700 g of pure water. The organic solvent layer was dried over magnesium sulfate, filtered, and the solvent was distilled off under reduced pressure. By recrystallizing the obtained oil, the target compound bis (p-
tert-butoxyphenyl) sulfoxide with a purity of 96
%, 83 g (yield 6) as white crystals having a melting point of 80 to 82 ° C.
0%).

[0043]

Embedded image<¹H-NMR: CDCl_Three, Δ (ppm)> nuclear magnetic resonance
Spectrum 1.34 Ha Singlet 18H 7.01-7.04 Hb Doublet 4H 7.48-7.51 Hc Doublet 4H <IR: (cm^-1)> 2976, 2931, 1589,
1487, 1392, 1367, 1302, 1238,
1159, 1090, 1043, 1009, 930, 8
93,852,827<MS: (m / z)> mass spectrum 346 (M⁺): 331,290 (C₂₀H₂₆O_ThreeS = 34
6) <m. p. : (° C)> melting point 80-82 ° C

Synthesis Example 2 Trifluoromethanesulfonic acid (p-tert-butoxy)
(Ciphenyl) bis (p-dimethylaminophenyl) sul
6. Synthesis of phonium bis (p-dimethylaminophenyl) sulfoxide
A solution of 0 g (0.024 mol) dissolved in 100 g of methylene chloride was subjected to -7 using a dry ice methanol bath.
After cooling to 0 ° C., trimethylsilyl triflate6.
0 g (0.027 mol) was stirred and added dropwise while controlling the temperature so as not to exceed −60 ° C.

Then, the reaction temperature was adjusted to 0 to 5 ° C. by replacing the dry ice methanol bath with an ice water bath, followed by stirring for 10 minutes.

The obtained reaction solution was cooled again to -70 ° C. using a dry ice methanol bath, and 1.2 g (0.049 mol) of metallic magnesium, 13.4 g of tetrahydrofuran and p-tert-butoxyphenyl were added. A Grignard reagent prepared by a conventional method using 9.8 g (0.053 mol) of chloride was added dropwise while controlling the reaction temperature not to exceed −60 ° C.

Next, the bath was replaced with an ice-water bath again, and the reaction temperature was set to 0 to 0.
The mixture was further stirred for 60 minutes at 5 ° C. to complete the reaction.

After water was added dropwise to the obtained reaction solution to decompose excess Grignard reagent, filtration was performed to remove the generated inorganic salts. The obtained filtrate was washed three times with 130 g of water. The obtained organic layer was dried under reduced pressure to obtain an oily substance. The obtained oil was subjected to silica gel column chromatography to give a yield of 3.9 g (yield 28%) and a purity of 99%.
(P-tert-butoxyphenyl) bis (p-dimethylaminophenyl) sulfonium trifluoromethanesulfonate was isolated.

The results of nuclear magnetic resonance spectrum (NMR), infrared spectrum (IR), and elemental analysis of the obtained (p-tert-butoxyphenyl) bis (p-dimethylaminophenyl) sulfonium trifluoromethanesulfonate are shown below. Shown below. < ¹ H-NMR: CDCl ₃ , δ (ppm)>

[0050]

Embedded image (A) 1.36 singlet 9H (b) 2.99 singlet 12H (c) 6.73 to 6.76 doublet 4H (e) 7.08 to 7.11 doublet 2H (d), (F) 7.29 to 7.34 Multiplet 6H <IR: (cm ⁻¹ )> 3097, 2978, 2929,
2908, 2870, 2825, 1589, 1551,
1518, 1487, 1446, 1373, 1265
1223, 1200, 1155, 1074, 1030,
991,943,893,816 <Elemental _{analysis: (%) C 27 H 33} F 3 N 2 O 4 S 2> theory C: 56.8 H: 5.8 N: 4.9 Found C: 56 .6 H: 6.1 N: 4.9

[Synthesis Example 3] Tris (4-dimethylamine ) trifluoromethanesulfonate
6. Synthesis of minophenyl) sulfonium bis (4-dimethylaminophenyl) sulfoxide
A solution of 0 g (0.024 mol) dissolved in 100 g of methylene chloride was subjected to -7 using a dry ice methanol bath.
After cooling to 0 ° C., trimethylsilyl triflate6.
0 g (0.027 mol) was stirred and dropped at a temperature not exceeding -60 ° C.

Then, the reaction temperature was adjusted to 0 to 5 ° C. by replacing the dry ice methanol bath with an ice water bath, followed by stirring for 10 minutes.

After the obtained reaction solution was cooled again to -70 ° C. using a dry ice methanol bath, 9.9 g (0.049 mol) of 4-bromo-N, N-dimethylaniline and 1.19 g of metallic magnesium were added. A Grignard reagent prepared by a conventional method using 2 g (0.049 mol) and 20 g of tetrahydrofuran was stirred and dropped at a temperature at which the reaction temperature did not exceed -60 ° C.

Next, the bath was replaced with an ice-water bath again, and the reaction temperature was set to 0 to 0.
The mixture was stirred at 5 ° C. for 60 minutes to complete the reaction.

After adding 300 g of a 15% ammonium chloride aqueous solution to the reaction solution to carry out liquid separation, the organic solvent layer was washed twice with 150 g of water. The solvent was distilled off from the obtained organic layer under reduced pressure using a rotary evaporator to obtain an oily substance. The resulting oil was subjected to silica gel column chromatography to give a yield of 5.2 g (40% yield) and a purity of 99%.
Of tris (4-dimethylaminophenyl) sulfonium trifluoromethanesulfonate was obtained.

The nuclear magnetic resonance spectrum (NMR) and infrared spectrum (I) of the obtained tris (4-dimethylaminophenyl) sulfonium trifluoromethanesulfonate were obtained.
R) and the results of elemental analysis are shown below. < ¹ H-NMR: CDCl ₃ , δ (ppm)>

[0057]

Embedded image (A) 3.01 singlet 18H (b) 6.72 to 6.75 doublet 6H (c) 7.23 to 7.26 doublet 6H <IR: (cm ⁻¹ )> 2910, 1591, 1550,
1515, 1444, 1375, 1272, 1222
1199, 1145, 1076, 1031, 991, 9
43,811,638,520 <Elemental _{analysis: (%) C 25 H 30} O 3 N 3 S 2 F 3> theory C: 55.4 H: 5.6 N: 7.8 Found C: 55 .3 H: 5.6 N: 7.7

Examples 1 to 11 and Comparative Examples 1 to 4 OH groups represented by the following formula (Polym.
Polyhydroxystyrene protected with a butoxycarbonyl group, partially represented by the following formula (Polym. 2):
A polyhydroxystyrene in which an H group is protected by a t-butyl group, a polyhydroxystyrene represented by the following formula (Polym.3) and a OH group partially protected by a tetrahydroxypyranyl group, and the following formula (PAG.1) ) To (PAG.7), an acid generator selected from the onium salts represented by (PAG.7), and 2,2 ′ represented by the following formula (DRI.1).
A dissolution inhibitor of -bis (4-tert-butoxycarbonyloxyphenyl) propane was dissolved in 1-ethoxy-2-propanol, and a resist solution having the composition shown in Tables 1 and 2 was prepared.

Each of these compositions was filtered through a 0.2 μm Teflon filter to prepare a resist solution. This was spin-coated on a silicone wafer and applied to a thickness of 1.0 μm. Next, the silicone wafer was baked on a hot plate at 100 ° C. for 120 seconds.

Then, exposure was performed using an excimer laser stepper (Nikon Corporation, NSR 2005EX NA = 0.5), baking was performed at 90 ° C. for 60 seconds, and development was performed using a 2.38% aqueous solution of tetramethylammonium hydroxide. As a result, a positive pattern was obtained.

The obtained resist pattern was evaluated as follows. First, the sensitivity (Eth value) was determined. Next, 0.
4 μm line and space top and bottom:
The exposure amount resolved at 1 was taken as the optimum exposure amount, and the minimum line width of the separated lines and spaces at this exposure amount was taken as the resolution of the evaluation resist. The shape of the resolved resist pattern was observed using a scanning electron microscope. The stability of the PED of the resist is as follows: after exposure at the optimal exposure amount, the baking time is changed by changing the leaving time, and the time when the change in the resist pattern shape is observed, for example, the line pattern becomes a T-top shape or can be resolved. It was evaluated at the time when it disappeared. That is, the longer this time, the better the PED stability. Table 1 shows the evaluation results and Table 2 shows the comparative examples.

[0062]

Embedded image

[0063]

Embedded image

[0064]

Embedded image Note that PAG. 4 and PAG. No. 5 was synthesized in the same manner as in the above synthesis example.

[0065]

Embedded image

[0066]

[Table 1]

[0067]

[Table 2]

──────────────────────────────────────────────────続 き Continuing on the front page (51) Int.Cl. ⁶ Identification symbol FI H05K 3/08 H05K 3/08 A (72) Inventor Yoichi Osawa 28-1 Nishifukushima, Ojiku, Kushiro-mura, Nakakubiki-gun, Niigata Shin-Etsu Chemical Co., Ltd. Synthetic Technology Research Inc. (72) Inventor Katsuya Takemura 28-1 Nishifukushima, Nishi-Jukumura, Nakakushiro-gun, Niigata Prefecture Shin-Etsu Chemical Co., Ltd.Synthetic Technology Research Institution (72) Inventor, Toshinobu Ishihara Niigata Pref. 28-1 Nishifukushima Shin-Etsu Chemical Co., Ltd., Synthetic Technology Research Institute (72) Inventor Kazumasa Maruyama 28-1, Nishifukushima, Oku, Kushiro-mura, Nakakushiro-gun, Niigata Shin-Etsu Chemical Industry Co., Ltd. (Int.Cl. ⁶ , DB name) C07C 381/12 C08K 5/36 C03F 7/004 C03F 7/039 H05K 3/06 H05K 3/08 CA (STN)

Claims (5)

(57) [Claims] 1. A sulfonium salt represented by the following general formula (1). Embedded image (Wherein R ¹ , R ² , and R ³ are selected from a phenyl group, a tert-butoxyphenyl group, or a nitrogen-containing aromatic group;
^At least one of R ¹ , R ² and R ³ is a tert-butoxyphenyl group and at least one is a nitrogen-containing aromatic group, or R ¹ , R ² and R ³ are all a nitrogen-containing aromatic group And the nitrogen-containing aromatic group is a dialkylaminophenyl group having 1 to 8 carbon atoms of an alkyl group, a picolyloxyphenyl group or a pyridinyl group. ) 2. A chemically amplified positive resist material comprising the sulfonium salt according to claim 1. 3. A composition comprising (A) an organic solvent, (B) an alkali-soluble resin, (C) a dissolution inhibitor having an acid labile group, (D) a sulfonium salt according to claim 1, and (E) an acid generator. A chemically amplified positive resist material characterized by the following: 4. A chemical amplification comprising (A) an organic solvent, (B) an alkali-soluble resin, (C) a dissolution inhibitor having an acid labile group, and (D) a sulfonium salt according to claim 1. Positive resist material. 5. A polyhydroxystyrene having a weight average molecular weight of 5,000 to 100,000 in which a part of hydrogen atoms of a hydroxyl group is substituted by an acid labile group as the alkali-soluble resin of the component (B). 5. The resist material according to 3 or 4.