JPH08160621A - Positive type resist material - Google Patents

Abstract

PURPOSE: To provide a positive type resist material sensitive to high-energy beams, excellent in sensitivity, resolution, and oxygen plasma etching resistance, and capable of forming a fine pattern at a high aspect ratio. CONSTITUTION: A nitrogen containing compound is added to a positive resist material capable of being developed by an alkali aqueous solution containing two components of a silicone polymer expressed by the formula and an oxygen generating agent decomposed by the action of illuminating radioactive rays to generate oxygen. In the formula, Q indicates t-butoxy carbonyl group, t- butoxy carbonyl methyl group, trimethy silyl group, or tetrahydropyranyl group, (n) is an integer of 1-3, x+m=1, and (x) is non-zero.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
It has high sensitivity to high energy rays such as rays and can form a pattern by developing with an alkaline aqueous solution.
The present invention relates to a positive resist material suitable for fine processing technology.

[0002]

2. Description of the Related Art LSI to be Solved
Along with the high integration and high speed of chemicals, recently developed acid has been used as a catalyst for chemical amplification.
resist material [eg Liu (L
iu), etc., Journal of Vacuum Science and Technology (J. Vac. Sci. Tech.
nol. ), B6, 379 (1988)],
It has excellent characteristics that it has sensitivity equal to or higher than that of conventional high-sensitivity resist material, high resolution, and high dry etching resistance. Therefore, it is a particularly promising resist material for deep ultraviolet lithography. However, as a negative resist, Shipley has already commercialized a three-component chemically amplified resist material (trade name SAL601ER7) consisting of a novolak resin, a melamine compound and an acid generator, but it is a chemically amplified positive type resist. No resist material has been commercialized yet. Therefore, in the manufacturing process of the LSI, the negative resist material can be used for wiring and gate formation, but the contact hole formation is difficult to perform fine processing because a negative resist material is used. There has been a strong demand for a positive resist material. Conventionally, Ito et al. Developed a positive chemically amplified resist material by adding an onium salt to a resin called PBOCST in which an OH group of polyhydroxystyrene is protected by a t-butoxycarbonyl group (t-BOC group). ing.

However, the onium salt used contains antimony as a metal component [Reference: Polymers in Electronics, ACS Symposium Series (Polymers in Electro).
nics, ACS symposium Series
s) 242nd (American Chemical Society, Washington DC.
1984), p. 11], the PBOCST resist material is not preferable in the process from the viewpoint of preventing contamination of the substrate.

On the other hand, Ueno et al. Have announced a deep UV chemical amplification type positive resist material containing poly (p-styreneoxytetrahydropyranyl) as a main component and having high sensitivity and high resolution (reference: No. 1). The 36th Joint Lecture Meeting of Japan Society of Applied Physics, 1989, 1p-k-7), it was difficult to form a fine pattern having a high aspect ratio with high precision because of the mechanical strength of the pattern.

As described above, a number of chemically amplified positive resist materials based on novolac resins and polyhydroxystyrene, which are sensitive to deep ultraviolet rays, electron beams and X-rays, have been hitherto announced. All of them are single-layer resists, and there are still problems with substrate steps, problems with standing waves due to light reflection from the substrate, and problems with pattern formation with high aspect ratios. .

By the way, the two-layer resist method is excellent for forming a pattern having a high aspect ratio on a stepped substrate.
A silicone-based polymer having a hydrophilic group such as a hydroxy group or a carboxyl group is required for alkali development by the two-layer resist method, and silanol having a hydroxy group directly attached to the silicone causes a crosslinking reaction with an acid. Therefore, it has been difficult to apply it to a chemically amplified positive resist material. Polyhydroxybenzylsilsesquioxane is a stable alkali-soluble silicone polymer, and a material in which a part of the hydroxy group is protected by t-BOC is a chemically amplified silicone positive type in combination with an acid generator. It is known to be used as a resist material (JP-A-6-118651 or SPIE Vo).
l. 1925 (1993) 377).

However, these resist materials have a problem of post-exposure delay (PED), which is a problem of chemically amplified resist materials. The problem of PED is caused by impurities such as amine components and water in the atmosphere after exposure diffusing from the resist surface, resulting in distribution of impurities in the film. In particular, the pattern shape becomes "T-top" because the acid is easily deactivated by impurities on the surface. There is still no silicone-based positive resist material that has solved the problem of T-top in PED.

[0008] The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide a chemically amplified silicone-based positive resist material which is suitable as a two-layer resist material and has high sensitivity, high resolution, and excellent PED stability.

[0009]

Means and Actions for Solving the Problems As a result of intensive studies for achieving the above-mentioned object, the present inventor has found that a silicone polymer represented by the following general formula (1), an acid generator, and if necessary, It was found that the problem of post-exposure delay (PED), which is a problem of chemically amplified resist materials, can be solved by adding a nitrogen-containing compound to a positive resist material containing a dissolution inhibitor as a main component. . The problem of PED is that impurities such as amine components and water in the atmosphere after exposure diffuse from the resist surface,
It is caused by creating a distribution of impurities in the film. In particular, since the acid is easily deactivated by impurities on the surface, the pattern shape becomes “T top”. By adding a nitrogen-containing compound to the resist material, it is possible to reduce the influence of impurities. It was also confirmed that the pattern dimensional controllability was improved by adding a nitrogen-containing compound because the acid diffusion rate could be reduced.

[0010]

Embedded image (In the formula, Q represents a t-butoxycarbonyl group, a t-butoxycarbonylmethyl group, a trimethylsilyl group or a tetrahydropyranyl group. N is an integer of 1 to 3, x and m are x.
Although + m = 1, x never becomes 0. )

Therefore, the present invention comprises two components, a silicone polymer represented by the general formula (1) and an acid generator which decomposes to generate an acid by the action of irradiation radiation, and if necessary, a dissolution inhibitor. Provided is a positive resist material, which is obtained by adding a nitrogen-containing compound to a positive resist material that can be developed with an aqueous alkaline solution.

The present invention will be described in more detail below. The polymer used in the positive resist composition of the present invention is
It is a silicone polymer represented by the following general formula (1).

[0013]

Embedded image

Here, Q is a t-butoxycarbonyl group,
A t-butoxycarbonylmethyl group, a trimethylsilyl group or a tetrahydropyranyl group is shown. n shows the integer of 1-3. Further, x and m are x + m = 1, but x is a positive number of 0, and m is 0 or a positive number of m> 0. However, when x in the formula is small, the effect of inhibiting dissolution is small, so that it becomes necessary to add an inhibitor. As x increases, the alkali solubility of the polymer decreases,
Inhibitors are no longer needed. x is preferably 0.05 to 0.5. If it is less than 0.05, the dissolution inhibiting effect is small, and if it is more than 0.5, the oxygen plasma etching resistance may be reduced due to the decrease in the silicone content. Moreover, 0.5
If it is larger than the above range, the solubility in an alkaline aqueous solution is extremely lowered, so that the sensitivity of a commonly used developer may be extremely lowered.

The weight average molecular weight of the silicone polymer used in the present invention is preferably 5,000 to 50,000. If it is less than 5,000, the desired plasma resistance may not be obtained, or the dissolution inhibiting effect in an alkaline aqueous solution may be low. If it is higher than 50,000, it may be difficult to dissolve in a general-purpose resist solvent. There is.

The t-group of the OH group of hydroxybenzyl
BOC formation is a method of protecting functional groups that is often used in peptide synthesis, and can be easily performed by reacting with di-t-butyl dicarbonate in a pyridine solution. Also,
Protecting the OH group with a t-butoxycarbonylmethyl group can be achieved by reacting a t-butyl bromoacetate with a silicone polymer.

The method of protecting the OH group with a trimethylsilyl group can be carried out almost quantitatively by reaction with trimethylsilyl chloride in the presence of a base such as triethylamine or pyridine.

Further, the method of converting the OH group into tetrahydropyranylation can be easily carried out by reaction with dihydropyran in the presence of a weak acid.

The t-butoxycarbonylmethyl group produces a carboxy group when it is decomposed with a catalytic acid.
Since it has better solubility than those protected with a group, a trimethylsilyl group, or a tetrahydropyranyl group, it has excellent resolution.

The blending amount of the silicone polymer used in the present invention is 55% (% by weight, the same applies hereinafter) or more based on the total blending amount of both the three-component system and the two-component system together with other components.
Particularly, 80% or more is preferable. If the blending amount is less than 55%,
The coating property of the resist material may be poor, or the strength of the resist film may be poor.

In the present invention, deep ultraviolet rays, electron beams, X
Rays are decomposed to irradiate high-energy rays to generate acid.
A generative acid generator is added, but as such an acid generator,
Oximesulfonic acid derivative, 2,6-dinitrobenzyl
Sulfonic acid derivative, naphthoquinone-4-sulfonic acid derivative
Body, 2,4-bistrichloromethyl-6-aryl-
1,3,5-triazine derivative, α, α′-bisary
Lusulfonyl diazomethane and the like can be mentioned. But Naga
These acid generators can obtain highly sensitive resist.
In some cases, the following general formula (2) (R )_pJM (2) (In the formula, R Are the same or different aromatic groups or substituted aromatic groups
, J represents sulfonium or iodonium, and M
Is a toluene sulfonate group or trifluoromethane
Indicates a ruphonate group. p is 2 or 3. )
Onium salts are preferably used.

Examples of such onium salts include compounds represented by the following formulas, which can be used.

[0023]

[Chemical 4]

However, none of these acid generators has a low solubility in a solvent which is widely used and suitable for coating resist materials such as ethyl cellosolve acetate, ethyl lactate, and ethoxy-2-propanol. It may be difficult to mix the proper amount into the material. Further, even if it has a high solubility in a solvent, it is difficult to form a good resist film due to its poor compatibility with a silicone polymer, and it is necessary to perform heat treatment after light irradiation. However, there is a defect that the sensitivity change and the pattern shape change with time tend to occur. Particularly in the case of an acid generator having poor compatibility, distribution may occur in the resist film and an overhang may be observed on the pattern surface. In a chemically amplified resist material, such a phenomenon often occurs because the acid is deactivated on the surface of the resist film or the acid generator is lost on the surface.

[0025] Accordingly, further preferably as an onium salt acid generator used, at least one of R ¹ ₃ CO- (R ¹ is an alkyl group having 1 to 10 carbon atoms for R in formula (2), an aryl group A substituted or unsubstituted monovalent hydrocarbon group)
An onium salt of a phenyl group substituted with a t-alkoxy group, a t-butoxycarbonyloxy group, or a t-butoxycarbonylmethoxy group represented by is preferably used. These onium salts are easily dissolved in general-purpose resist solvents, and not only have good compatibility with silicone polymers, but also have excellent solubility after exposure,
The pattern can be formed perpendicular to the substrate. At this time, at least one of Rs in the general formula (2) is a t-alkoxyphenyl group, a t-butoxycarbonyloxyphenyl group, or a t-butoxycarbonylmethoxyphenyl group, and therefore, a phenolic hydroxyl group or a carboxyl group is used during exposure and heat treatment. The formation of acid improves the solubility after exposure. Generally, onium salts have a dissolution inhibiting effect, but these onium salts have a dissolution promoting effect after exposure. Therefore, the difference in the dissolution rate before and after the exposure can be increased, and therefore it is preferably used. The larger the number of R substituted with a t-alkoxy group, a t-butoxycarbonyloxy group, or a t-butoxycarbonylmethoxy group, the better the solubility tends to be.

At least one R in the general formula (2) is a t-alkoxy group, a t-butoxycarbonyloxy group,
Alternatively, examples of the onium salt substituted with a t-butoxycarbonylmethoxy group include compounds represented by the following formula.

[0027]

Embedded image (In the formula, Tf represents p-trifluoromethanesulfonate, Ts represents p-toluenesulfonate, and t-B
OC represents a t-butoxycarbonyl group. )

The content of the acid generator is 0.5 to 15
%, Especially 1 to 10% is preferred. If it is less than 0.5%, positive resist characteristics are exhibited, but the sensitivity is low. When the content of the acid generator is increased, the resist sensitivity tends to be higher, the contrast (γ) is improved, and the positive type resist property is exhibited even if it is more than 15%. Due to the fact that sensitivity cannot be expected, the onium salt is an expensive reagent, the increase in low molecular weight components in the resist decreases the mechanical strength of the resist film, and the oxygen plasma resistance also decreases. Content of 1
It is preferably 5% or less.

The resist composition of the present invention can be used not only as a two-component resist composition comprising a silicone polymer represented by the general formula (1) and an acid generator, but also as a three-component composition containing a dissolution inhibitor if necessary. It can also be used as a system resist material.

As such a dissolution inhibitor, there are known 3
The same material as the component-based resist material can be used. For example, a material obtained by converting the OH group of bisphenol A represented by the following formula into t-BOC, or a material obtained by converting t-BOC such as phloroglucin or tetrahydroxybenzophenone into Can be used.

[0031]

[Chemical 6]

The content of the dissolution inhibitor is preferably 40% or less,
It is particularly preferably set to 10 to 30%. When it is more than 40%, the oxygen plasma resistance of the resist film is remarkably lowered, so that it cannot be used as a two-layer resist.

In the present invention, a nitrogen-containing compound is further added in addition to the above components. As the nitrogen-containing compound,
Some are liquid at room temperature such as N-methylaniline, toluidine, N-methylpyrrolidone, and some are solid at room temperature such as aminobenzoic acid and phenylenediamine. Since liquids generally have a low boiling point, they may evaporate during prebaking of the resist film and may not work effectively. Therefore, among these, o-aminobenzoic acid, m-aminobenzoic acid, p-aminobenzoic acid, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, and diphenylamine can be preferably used.

The amount of the nitrogen-containing compound blended is preferably 0.01 to 1% of the total amount of the resist composition, and particularly 0.1.
.About.0.5% is preferable. If it is less than 0.01%, it is difficult to obtain the effect of adding a nitrogen-containing compound, and if it is 1% or more, the sensitivity is remarkably lowered, which is not preferable.

The resist material of the present invention can be prepared by dissolving the above silicone polymer, acid generator, nitrogen-containing compound and, if necessary, a dissolution inhibitor in an organic solvent. Is sufficiently dissolved and the resist film spreads uniformly,
Specific examples include butyl acetate, xylene, acetone, cellosolve acetate, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, ethyl lactate, methyl lactate, propyl lactate and butyl lactate. be able to. These organic solvents may be used alone or in combination of two or more. The amount of the organic solvent blended is preferably several times the total amount of the above components.

The resist material of the present invention may further contain a surfactant and the like.

The pattern formation using the resist material of the present invention can be performed, for example, as follows. First, the resist solution of the present invention is spin-coated on a substrate, prebaked, and irradiated with a high energy ray. At this time, the acid generator decomposes to generate an acid. PEB (Post E
By carrying out xpose Bake), the acid labile group is decomposed by using an acid as a catalyst and the dissolution inhibiting effect disappears. Then, a positive type pattern can be formed by developing with an alkaline aqueous solution and rinsing with water.

Further, the resist of the present invention, which uses a silicone polymer as a base resin, is excellent in oxygen plasma etching resistance and is therefore useful as a two-layer resist.

That is, after forming a thick organic polymer layer as a lower layer resist on a substrate, the resist solution of the present invention is spin coated thereon. The upper resist layer of the present invention is patterned by the same method as described above, and then the lower resist is selectively etched by etching, so that the upper resist pattern can be formed in the lower layer.

As the lower layer resist, a novolac resin type positive type resist can be used, and after being coated on a substrate, it is hard baked at 200 ° C. for 1 hour to prevent intermixing with the silicone type resist. it can.

[0041]

Since the positive resist composition of the present invention is sensitive to high energy rays and has excellent sensitivity and resolution, it is useful for fine processing with electron beams or deep ultraviolet rays. Especially Kr
Since the absorption at the exposure wavelength of the F excimer laser is small,
The feature is that a fine pattern can be easily formed perpendicular to the substrate. Further, since it has excellent resistance to oxygen plasma etching, the two-layer resist in which the resist film of the present invention is applied on the lower layer resist is also characterized in that a fine pattern can be formed with a high aspect ratio.

[0042]

EXAMPLES Hereinafter, the present invention will be specifically described by showing synthesis examples, examples and comparative examples, but the present invention is not limited to the following examples.

[Synthesis Example 1] Synthesis of p-hydroxybenzylsilsesquioxane 600 ml of water was charged to a reactor, and 283.5 g of p-methoxybenzyltrichlorosilane was stirred at 30 ° C.
A mixed solution of (1 mol) and 300 ml of toluene was added dropwise over 2 hours for hydrolysis. After the aqueous layer was removed by a liquid separation operation, the solvent was distilled off from the organic layer using an evaporator.
The concentrated solution was heated at 200 ° C. under reduced pressure for 2 hours to polymerize. Add 200 g of acetonitrile to the polymer to dissolve it,
240 g of trimethylsilyl iodide was dropped into the solution at a temperature of 60 ° C. or lower, and reacted at 60 ° C. for 10 hours. After completion of the reaction, 200 g of water was added for hydrolysis, and then a polymer layer was obtained by decanting. The polymer layer was vacuum dried to obtain 165 g of poly p-hydroxybenzylsilsesquioxane.

[Synthesis Example 2] t-butoxycarbonyl (t-BO) of polyhydroxybenzylsilsesquioxane
C) Polyoxybenzyl silsesquioxane (Synthesis Example 1) (25 g) was dissolved in pyridine (250 g), and di-t-butyl dicarbonate (6.85 g, 0.05) was added while stirring at 45 ° C.
31 mol, corresponding to about 20 mol% with respect to the OH group) was added. A gas was generated at the same time as the addition, but the reaction was carried out for 1.5 hours in a N ₂ stream. The reaction solution was stripped with pyridine, dissolved in 100 ml of methanol, and added dropwise to 5 liters of water to obtain a white precipitate. The precipitate was washed with water 5 times, filtered, and vacuum dried at 40 ° C. or below.
25 g of t-butoxycarbonylated polyhydroxybenzylsilsesquioxane was obtained. ¹ H-NMR
At 6 to 7 ppm of phenyl group and 1-2
From the t-butyl group of ppm and the peak of methylene, t
The BOC conversion rate was calculated to be 19.6%.

[Synthesis Example 3] t-Butoxycarbonylmethylation of polyhydroxybenzylsilsesquioxane 25 g of polyhydroxybenzylsilsesquioxane (Synthesis Example 1) was dissolved in 250 g of pyridine, and t- was added while stirring at 45 ° C. Butyl bromoacetate 8.89g
(0.045 mol) was added, and the mixture was reacted for 5 hours in N ₂ stream. The reaction solution was stripped with pyridine, dissolved in 100 ml of methanol, and added dropwise to 5 liters of water to obtain a white precipitate. The precipitate was washed with water 5 times, filtered, and dried under vacuum at 40 ° C. or lower to obtain 24 g of t-butoxycarbonylmethylated polyhydroxybenzylsilsesquioxane. ^{In 1} H-NMR, peak of phenyl group at 6-7 ppm and 1-2 ppm
As a result of obtaining the introduction ratio of t-butoxycarbonylmethyl group from the peaks of t-butyl group and methylene of 20.
It was 6%.

[Synthesis Example 4] Trimethylsilylation of polyhydroxybenzylsilsesquioxane 25 g of polyhydroxybenzylsilsesquioxane (Synthesis Example 1) was dissolved in 40 ml of acetone, and 5.2 g of trimethylamine was added. 0.95 g of trimethylsilyl chloride was added with stirring at 45 ° C., and the mixture was refluxed for 2 hours for aging. The reaction solution was stripped with acetone, dissolved in 100 ml of methanol, and added dropwise to 5 liters of water to obtain a white precipitate. The precipitate was washed with water 5 times, filtered, and vacuum dried at 40 ° C. or lower to obtain 25 g of trimethylsilylated polyhydroxybenzylsilsesquioxane. ^{In 1} H-NMR,
The introduction rate of the trimethylsilyl group was determined from the peak of the phenyl group at 6 to 7 ppm and the peak of the methyl group of the trimethylsilyl group near 0 ppm, and the result was 19.0%.

[Synthesis Example 5] Tetrahydropyranylation of polyhydroxybenzylsilsesquioxane 25 g of polyhydroxybenzylsilsesquioxane (Synthesis Example 1) was dissolved in 40 ml of acetone, and 7.5 g of pyridinium tosylate was added, Dihydropyran 12.
9 g was added over 1 hour with stirring at room temperature. After aging at room temperature for 10 hours, the reaction solution was stripped with acetone, dissolved in 100 ml of methanol and added dropwise to 5 liters of water to obtain a white precipitate. The precipitate was washed with water 5 times, filtered, and vacuum dried at 40 ° C. or lower to obtain 20 g of tetrahydropyranylated polyhydroxybenzylsilsesquioxane. ¹ H-NMR
At a peak of 6 to 7 ppm of phenyl group and 5.5
As a result of obtaining the introduction rate of the tetrahydropyranyl group from the peak of the hydrogen at the α-position of the ppm tetrahydropyranyl group,
It was 18.9%.

Example 1 Base Resin (Synthesis Example 2) 96 parts by weight Tri (pt-butoxyphenyl) trifluoromethanesulfonate 4 parts by weight N-methylpyrrolidone 0.4 parts by weight 1-ethoxy-2- A resist solution consisting of 600 parts by weight of propanol was 2,000 rp on a silicon substrate
m and spin-coated at 85 ° C. for 1 minute on a hot plate. The film thickness was 0.4 μm. KrF
After drawing with an excimer laser or an electron beam with an acceleration voltage of 30 kV, PEB was performed at 85 ° C. for 2 minutes. 2.4%
Tetramethylammonium hydroxide (TMAH)
Development was carried out for 1 minute with an aqueous solution of, and rinsed with water for 30 seconds.

The present resist material exhibits positive characteristics,
The D ₀ sensitivity was 4.5 μC / cm ² . Instead of the electron beam, KrF excimer laser light (wavelength 2
48 nm) has an Eth sensitivity of 10 mJ / c.
m ² . The base resin used here showed a dissolution rate of 35 nm / s in the developing solution. The resist material had a dissolution rate of about 1.5 nm / s in the unexposed area and a dissolution rate of 40 nm / s in the exposed area after PEB.

With the KrF excimer laser exposure, 0.2
A 5 μm line-and-space pattern and a hole pattern were resolved, and a pattern having sidewalls perpendicular to the substrate could be formed. In electron beam writing, the resolution was 0.1 μm.

After the KrF excimer laser exposure, it was left in the atmosphere for 20 minutes and then PEB was performed. As a result, T-top formation was observed, and a line and space of 0.30 μm could be resolved.

Examples 2 to 18 A base resin, an acid generator and a nitrogen-containing compound having the same composition as in Example 1 were prepared as shown in Table 1. It was coated on a silicon wafer substrate under the same conditions as in Example 1 and exposed to KrF excimer laser. Table 1 shows the Eth sensitivity, the resolution line width of line and space, and the resolution line width when PEB was performed after exposure for 20 minutes in the air after exposure.

Example 19 Base Resin (Synthesis Example 2) 80 parts by weight Tri (pt-butoxyphenyl) trifluoromethanesulfonate 4 parts by weight t-BOC-modified bisphenol A 16 parts by weight N-methylpyrrolidone 0. A resist solution consisting of 4 parts by weight of 1-ethoxy-2-propanol 600 parts by weight was spin-coated on a silicon substrate at 2,000 rpm under the same conditions as in Example 1, and prebaked on a hot plate at 85 ° C. for 1 minute. The film thickness is 0.
It was 4 μm. KrF excimer laser exposure was performed. As a result, the Eth sensitivity was 10 mJ / cm ² , and the resolution line width of line and space was 0.25 μm. Table 2 shows the results.

[Examples 20 and 21] A composition similar to that of Example 19 was prepared as shown in Table 2 in place of the nitrogen-containing compound.
It was coated on a silicon wafer substrate under the same conditions as in Example 19 and exposed to KrF excimer laser. Table 2 shows the Eth sensitivity and the resolution line width of line and space.

[0055]

[Table 1]

[0056]

[Table 2]

Example 22 A resist solution having the same composition as in Example 1 was prepared, and OFPR800 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) as a lower layer resist was applied to a silicon wafer to a thickness of 2 μm and heated at 200 ° C. for 1 hour. And cured. The resist material of Example 1 was applied on the lower layer resist in the same manner as in Example 1 to a thickness of about 0.4 μm, and prebaked. In the same manner as in Example 1, exposure and development were performed with an electron beam or KrF excimer laser to form a pattern on the lower layer resist.

After that, etching was carried out with a parallel plate type sputter etching apparatus using oxygen gas as an etchant gas. Etching rate of lower layer resist is 150 nm / m
whereas the resist of the composition of Example 1 is 3n
It was below m / min. By performing the etching for 15 minutes, the lower layer resist not covered with the resist completely disappeared, and a two-layer resist pattern having a thickness of 2 μm or more could be formed. The etching conditions are shown below. Gas flow rate: 50 SCCM, gas pressure: 1.3 Pa rf power: 50 W, dc bias: 450 V

[Examples 23 to 42] Under the same conditions as in Example 22, the resist material of Examples 2 to 21 was used as a two-layer resist instead of the resist of Example 1, and the same pattern was formed. I was able to.

Comparative Example Base Resin (Synthesis Example 2) 96 parts by weight Tri (pt-butoxyphenyl) trifluoromethanesulfonate 4 parts by weight 1-ethoxy-2-propanol 600 parts by weight A nitrogen-containing compound consisting of A resist solution containing no resist was prepared, and the same resolution with a KrF excimer laser as in Example 1 was evaluated.

The Eth sensitivity is 5 mJ / cm ² , and a line and space of 0.25 μm can be resolved when PEB is performed immediately after the exposure, but the T-top can be left for 10 minutes after exposure in the atmosphere. Expression of 0.40 μm
Could not resolve the line and space of.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location G03F 7/075 521 H01L 21/027 (72) Inventor Toshinobu Ishihara Nishiki, Nakakubiki-gun, Niigata Prefecture Nishi 28-1 Fukushima Shin-Etsu Chemical Co., Ltd. Synthetic Technology Laboratory (72) Inventor Keijun Tanaka 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (72) Yoshio Kawai Chiyoda-ku, Tokyo Uchisaiwaicho 1-6-1 Nihon Telegraph and Telephone Corp. (72) Inventor Jiro Nakamura 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corp.

Claims (3)

[Claims] 1. The following general formula (1): (In the formula, Q represents a t-butoxycarbonyl group, a t-butoxycarbonylmethyl group, a trimethylsilyl group or a tetrahydropyranyl group. N is an integer of 1 to 3, x and m are x.
Although + m = 1, x never becomes 0. ), And a nitrogen-containing compound was further added to a positive resist material that can be developed with an alkaline aqueous solution containing two components: a silicone polymer and an acid generator that decomposes to generate an acid by the action of irradiation radiation. A positive resist material characterized by the following. 2. The acid generator is represented by the following general formula (2) (R )_pJM (2) (In the formula, R Are the same or different aromatic groups or substituted aromatic groups
, J represents sulfonium or iodonium, and M
Is a toluene sulfonate group or trifluoromethane
Indicates a ruphonate group. p is 2 or 3. )
The material according to claim 1, which is an onium salt. 3. The material according to claim 1, further comprising a dissolution inhibitor.