JP2906999B2 - 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 a resist material which is highly sensitive to radiation such as electron beams and X-rays, has high thermal stability, and is not easily affected by alkaline impurities from the environment and is suitable for semiconductor fine processing.

[0002]

2. Description of the Related Art The use of a resist material in microfabrication of a semiconductor is already a general technique.
At present, the use of high-energy ultraviolet rays, electron beams, X-rays, and other short-wave radiations is being studied in order to obtain images with a processing accuracy of 0.3 μm or less. It is becoming.

As one method for obtaining a resist material having high sensitivity and high resolution by using these radiations, a so-called chemically amplified resist material has been proposed (H. Ito).
Et al., Polym. Eng. Sci. , 23 volumes, 1023
Page (1983)).

The chemically amplified resist material is classified into a two-component system and a three-component system in the positive type. As a component of the two-component system, a compound which decomposes when irradiated with radiation to generate a strong acid, A compound containing a polymer compound which becomes alkali-soluble by an acid (Japanese Patent Application Laid-Open No. 2-209977, etc.), as a component of a three-component system, a compound which generates a strong acid by radiation, an alkali-soluble polymer compound, and this polymer There has been proposed a compound containing a dissolution inhibitor which prevents the compound from dissolving in alkali and decomposes with an acid to lose the dissolution inhibiting ability (JP-A-2-245756).

[0005] The resolution mechanism of these chemically amplified resist materials is such that even in the case of a positive type, a positive image is formed by utilizing a change in solubility of a polymer compound in a developing solution using a small amount of acid generated by irradiation with radiation as a catalyst. It is to resolve. For this reason, a very sharp change in resolution is caused to alkaline impurities. In particular, the problem is that alkaline impurities intrude from the surface due to environmental conditions.If alkaline substances enter the system after irradiation, the alkaline substances spread into the system over time until development, and the acid of the catalyst is neutralized. The catalyst loses its catalytic ability, hinders the change in solubility of the polymer compound in the area where the acid is neutralized, and forms a film insoluble in the developer near the surface layer in the positive type, resulting in a different size from the design. There is a problem that a pattern is formed. Although a method of further forming a protective film on the resist film has been adopted to prevent such a change in resolution and dimensional change, it cannot be said that it is a preferable method due to a problem such as an increase in steps.

It has been reported that the use of an acid generator containing a nitrogen atom with respect to such intrusion of alkaline impurities slows the intrusion of alkaline impurities and reduces dimensional fluctuations with time after irradiation. (JP-A-5-204159). It is considered that the effect of the acid generator containing a nitrogen atom does not hinder the reaction by the acid due to the buffering action of the strong acid weak base and prevents the diffusion of the basic impurities.

However, as a result of the inventor's actual use of a nitrogen atom-containing acid generator reported in the above publication, sufficient sensitivity may not always be obtained depending on the type of the polymer compound and the additive used. It has been found that polymer compounds and additives that can be used are limited.

Further, since the resist film is baked after light irradiation, if the resist film is unstable to heating, the resist film is decomposed by baking and the function as the resist film is impaired. It is required that it does not decompose at a moderate temperature.

The present invention has been made in view of the above circumstances, has high sensitivity to radiation such as high-energy ultraviolet rays, electron beams, and X-rays, has high thermal stability, and is hardly affected by alkaline impurities. It is another object of the present invention to provide a resist material which can use a wide range of polymer compounds and additives.

[0010]

Means and Action for Solving the Problems The present inventors have
As a result of intensive studies to achieve the above object, it is effective to use a glyoxime derivative represented by the following general formula (1) as a photoacid generator, and a resist material containing this compound as a photoacid generator is: It has high sensitivity to radiation such as high-energy ultraviolet rays, electron beams, and X-rays, has high thermal stability, is not easily affected by alkaline impurities, and can use a wide range of polymer compounds and additives. I learned.

[0011]

Embedded image (Wherein, R ¹ and R ² each independently represent an alkyl group,
Represents a cycloalkyl group, an aryl group or a heteroaryl group, or R ¹ and R ² are bonded to each other to form a cyclic structure. R ³ represents an alkyl group, a cycloalkyl group, an aryl group or a heteroaryl group. )

That is, the present inventors have found that among oxime derivatives which can be obtained much more easily than ketone derivatives, the oxime sulfonic acid ester is decomposed by irradiation to generate an acid, and this reaction occurs with high sensitivity. I found Therefore, first, a positive resist material was prepared and a resolution test was performed. For example, in the case of an oxime derivative obtained from acetone, even if heating after irradiation was about 90 ° C.
It was found that the unexposed portion was considerably dissolved in the developer. It was presumed that the reason for this was that the oxime derivative was partially thermally decomposed by the measurement of the decomposition point and an acid was generated thermally.

Therefore, sulfonic acid esters of oximes were prepared, and those having high thermal stability were searched for. As a result, sulfonic esters synthesized from dialkyl oximes and diaryl oximes do not show a clear decomposition point in the case of diaryl oximes, but all observed decomposition points of 150 ° C. or less, On the other hand, sulfonic acid ester derivatives synthesized from α-glyoximes do not show a clear decomposition point with aryl-substituted derivatives, but at least 170 ° C.
Up to 20% for the alkyl-substituted ones.
Demonstrates a decomposition point of 0 ° C or higher, has extremely good sensitivity to radiation, can be applied to both positive and negative types, and has a catalytic effect on a wide variety of polymer compounds and additives. In addition, it has been found that, since it contains a nitrogen atom, it has resistance to alkaline impurities, does not easily lose its catalytic action, and is extremely useful as an acid generator for resist materials.

A bis-O- having a glyoxime structure
Sulfonyl oximes are nervous system drugs (Remers.
W. A, et al., US Pat. No. 3,497,554 (1970)), or as an additive to oxygen bleaches (Finley.
J. H et al., US Pat. No. 4,164,395 (1979)), but the sensitivity to light has not been discussed at all. The present inventors have studied the thermal stability and radiation sensitivity of those compounds,
This is the first time that the above knowledge has been obtained.

Accordingly, the present invention provides a resist material comprising a glyoxime derivative represented by the above general formula (1) as a photoacid generator.

Hereinafter, the present invention will be described in more detail. The resist material of the present invention contains a glyoxime derivative represented by the following general formula (1) as a photoacid generator as described above.

[0017]

Embedded image

In the above formula, R ¹ and R ² each independently represent a C 1-20 alkyl group such as a methyl group, an ethyl group, or a propyl group, particularly an alkyl group having 1-12 carbon atoms or a C 3 carbon atom such as cyclohexane and cycloheptane. -7, especially 5-7 cycloalkyl group, phenyl group, tolyl group, xylyl group, etc.
18, particularly 6 to 14 aryl groups, or 3 to 20 carbon atoms having an oxygen atom, a nitrogen atom, a sulfur atom, etc.
12 heteroaryl groups. Alternatively, R ¹ and R ² may be bonded to each other to form a cyclic structure. in this case,
The total number of carbon atoms of R ¹ and R ² is preferably about 2 to 5.

R ³ is the same alkyl group, cycloalkyl group, aryl group or heteroaryl group as R ¹ and R ² described above.

Specific examples of the glyoxime derivative represented by the above formula (1) are shown below together with their decomposition points. The oxime derivative and its decomposition point are also shown for comparison. <Types of glyoxime derivatives> bis-O- (p-toluenesulfonyl) -α-dimethylglyoxime: decomposition point: 205 ° C bis-O- (p-toluenesulfonyl) -α-diphenylglyoxime: decomposition point: 180 ° C (Unclear) bis-O- (p-toluenesulfonyl) -α-cyclohexaneglyoxime: decomposition point: 213 ° C. bis-O- (p-toluenesulfonyl) -2,3-butanedioneglyoxime: decomposition point: 184 ° C bis-O- (p-toluenesulfonyl) -1-methyl-
3,4-pentanedione glyoxime:
Decomposition point: 211 ° C Bis-O- (n-butylsulfonyl) -α-dimethylglyoxime: Decomposition point: 189 ° C Bis-O- (n-butylsulfonyl) -α-diphenylglyoxime: Decomposition point: 174 ° C ( Oxime derivative) O- (p-toluenesulfonyl) -benzophenone oxime: decomposition point: 100 ° C. (unclear) O- (p-toluenesulfonyl) -acetone oxime:
Decomposition point: 133 ° C. From this, it is recognized that the thermal stability of sulfonyl-α-glyoximes is good and that this thermal stability does not depend on the substituent on the oxime side and the substituent on the sulfonyl side.

The method for synthesizing the glyoxime derivative represented by the general formula (1) is described in the above-mentioned reference (Remers.
A, et al., US Pat. No. 3,497,554 (1970)). More specifically, it can be easily synthesized from α-diketone via α-glyoxime.

The resist material of the present invention contains the glyoxime derivative of the above formula (1) as a photoacid generator. As other components of the resist material, known components depending on the type are used. In addition, as for the method of using the resist material, a normal method of use according to the type is employed, and the resist material can be used in the same manner as a known positive resist material.

The resist composition of the present invention can be used as a positive type by selecting other components as described above. More specifically, the positive type is prepared as a two-component system or a three-component system. can do. The two-component resist material comprises (A) a glyoxime derivative (acid generator) represented by the general formula (1), and (B) a polymer compound which is insoluble in aqueous alkali but becomes alkali-soluble by acid. And a form in which these components are dissolved in a solvent. The polymer compound in this case is not particularly limited as long as it becomes alkali-soluble using an acid as a catalyst, and examples thereof include acids such as a tertiary butoxy group, a tertiary butoxycarbonyloxy group, a tetrahydropyranyl group, and a trimethylsilyl group. Polyhydroxystyrene protected or partially protected by a protecting group which can be eliminated by the above, and copolymers thereof, copolymers containing polymaleic anhydride, and the like.Examples of the polymerization method include radical polymerization and living polymerization. Obtainable. The amount of the glyoxime derivative represented by the general formula (1) in the positive type two-component resist is as follows:
The amount may be 0.1 to 50 parts, preferably 1 to 20 parts, per 100 parts (parts by weight, hereinafter the same) of the polymer compound (B).

Solvents for dissolving these components include, for example, 1-methoxy-2-propanol, 1-ethoxy-
Examples thereof include 2-propanol, ethyl lactate, polyethylene glycol dimethyl ether, and ethyl cellosolve acetate.

The positive type three-component resist material includes (A) a glyoxime derivative represented by the above general formula (1), (B) a polymer compound soluble in an aqueous alkaline solution or soluble in an acid, (C) ) It has at least one C—O—C bond or C—O—Si bond that can be cleaved by an acid, has the ability to prevent the dissolution of the polymer compound (B) in an aqueous alkaline solution, It can be configured to contain three components of a compound (dissolution inhibitor) which loses this stopping power by cleavage, and to dissolve these components in a solvent.

In this case, the polymer compound of the component (B) is
There is no particular limitation as long as the polymer compound itself or the dissolution inhibitor reacts with the acid catalyst to become water-soluble, and is not particularly limited. Examples thereof include a tertiary butoxy group, a tertiary butoxycarbonyloxy group, a tetrahydropyranyl group, and a trimethylsilyl group. Polyhydroxystyrene protected or partially protected by a protecting group that can be eliminated by an acid such as, or unprotected polyhydroxystyrene,
And copolymers thereof, copolymers containing polymaleic anhydride, and the like. Examples of the polymerization method include radical polymerization and living polymerization.

The dissolution inhibitor of the component (C) reduces the solubility of the polymer compound in an alkaline solution by being mixed with the polymer compound of the component (B), and the acid generated from the component (A). Has at least one C—O—C bond or C—O—Si bond that can be cleaved by
Any compound can be used as long as it can lose the alkali dissolution inhibiting ability of the polymer compound (B) or increase the solubility by reacting with the acid, but specifically, tert-butoxy. A phenol derivative or a carboxylic acid derivative protected by a protecting group which can be eliminated by an acid such as a group, a tertiary butoxycarbonyloxy group, a tetrahydropyranyl group, a trimethylsilyl group can be exemplified.

The amount of the components (A) to (C) in the positive type three-component resist material is 0.1 to 30 parts, preferably 1 to 30 parts, per 100 parts of the component (B). 2
0 parts, 5 to 50 parts of component (C), preferably 10 to 30 parts
It is preferable to set the range of parts.

A surfactant may be added to the positive type three-component resist material, if necessary, in addition to these components. Examples of the solvent include those exemplified for the two-component system.

[0030]

EXAMPLES Hereinafter, the present invention will be specifically described with reference to Synthesis Examples, Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Synthesis Example 1] 21 g (0.1 mol) of benzyl was dissolved in 100 ml of ethanol.
7.6 g (0.2 mol) were suspended. To this, an aqueous solution 5 of 13.9 g (0.2 mol) of hydroxylamine hydrochloride was added.
0 ml was added slowly, and the mixture was stirred at room temperature for 1 hour. Furthermore,
After refluxing for 4 hours, the solvent was concentrated under reduced pressure, and water was added to obtain 20.4 g of α-diphenylglyoxime as crystals. This was washed with water and dried in a desiccator.

Dried α-diphenylglyoxime 1
2 g (0.05 mol) was dissolved in 50 g of pyridine and cooled to 5 ° C. in an ice bath. To this, 22.8 g (0.12 mol) of p-toluenesulfonic acid chloride was slowly added, and the mixture was stirred at the same temperature for 4 hours. Next, water 100 was added to the reaction solution.
The resulting mixture was stirred for 30 minutes, and the precipitated crystals were collected by filtration. The crystals were purified by silica gel column chromatography (elution solvent: chloroform) to give 10.9 g of bis-O- (p-toluenesulfonyl) -α-diphenylglyoxime having a melting point of 94 ° C and a decomposition point of 185 ° C (unclear). Obtained as crystals.

[Synthesis Example 2] 5.8 g (0.05 mol) of α-dimethylglyoxime was dissolved in 50 g of pyridine.
Cooled to 5 ° C. in an ice bath. To this was slowly added 22.8 g (0.12 mol) of p-toluenesulfonic acid chloride,
The mixture was stirred at the same temperature for 4 hours. Next, water 1 was added to the reaction solution.
After adding 00 ml and stirring for 30 minutes, the precipitated crystals were collected by filtration. The crystals were purified by silica gel column chromatography (eluent: chloroform) to give a decomposition point of 205.
9.6 g of bis-O- (p-toluenesulfonyl) -α-dimethylglyoxime at ° C. was obtained as colorless crystals.

[Synthesis Example 3] 12 g (0.05 mol) of α-diphenylglyoxime obtained in Synthesis Example 1 was added to pyridine 50
g and cooled to 5 ° C. in an ice bath. To this, 18.8 g (0.12 mol) of n-butylsulfonic acid chloride was slowly added, and the mixture was stirred at the same temperature for 10 hours. next,
100 ml of water was added to the reaction solution, and the mixture was stirred for 30 minutes, and the precipitated crystals were collected by filtration. The crystals were purified by silica gel column chromatography (elution solvent: chloroform).
Bis-O- having a melting point of 126 ° C and a decomposition point of 174 ° C (unclear)
10.9 g of (n-butylsulfonyl) -α-diphenylglyoxime was obtained as colorless crystals.

Example 1 A positive resist solution having the following composition was prepared. 30% tetrahydropyranyl group-protected poly-p-hydroxystyrene: 2.0 g di-tert-butoxycarbonylbisphenol A: 0.4 g bis-O- (p-toluenesulfonyl) -α-diphenylglyoxime: 0.1 g methoxy Propanol: 12 ml This resist solution was dropped on the wafer surface, formed into a film with a spin coater, pre-baked at 100 ° C. for 2 minutes, and measured to have a thickness of 0.95 μm.
Met. The wafer was exposed to a line-and-space image at an exposure of 5 mJ / cm ² using a stepper having a numerical aperture of 0.5 and having a light source having a wavelength of 248 nm as a light source.
Baking at 2.degree. C. and development with 2.38% tetramethylammonium hydroxide gave a 0.3 .mu.m line and space resolution. After the exposure, the wafer was left in a laboratory for 3 hours, and then baked, whereby a good pattern was obtained.

Example 2 A positive resist solution having the following composition was prepared. 30% t-butoxycarbonyl group protected poly-p-hydroxystyrene: 2.0 g di-t-butoxycarbonyl bisphenol A: 0.4 g bis-O- (p-toluenesulfonyl) -α-diphenylglyoxime: 0.1 g Methoxypropanol: 12 ml This resist solution was dropped on the wafer surface, formed into a film with a spin coater, pre-baked at 100 ° C. for 2 minutes, and measured to have a thickness of 0.95 μm.
Met. The wafer was exposed to a line-and-space image at an exposure of 4 mJ / cm ² using a stepper having a numerical aperture of 0.5 and having a light source having a wavelength of 248 nm as a light source.
Baking and developing with 2.38% tetramethylammonium hydroxide gave a 0.3 μm line and space resolution. After the exposure, the wafer was left in the laboratory for 3 hours and then baked.
A good pattern was obtained.

Example 3 A positive resist solution having the following composition was prepared. 30% tetrahydropyranyl group-protected poly-p-hydroxystyrene: 2.0 g bis-O- (p-toluenesulfonyl) -α-diphenylglyoxime: 0.1 g methoxypropanol: 12 ml This resist solution was dropped on the wafer surface. After forming the film with a spin coater, pre-baking was performed at 100 ° C. for 2 minutes, and the thickness of the resist film was measured to be 0.95 μm
Met. This wafer was 4.5 mJ / cm ^{2 by} a stepper having a numerical aperture of 0.5 and having a light source having a wavelength of 248 nm as a light source.
Expose the line and space image at an exposure of
Baking at 00 ° C. and development with 2.38% tetramethylammonium hydroxide gave a 0.3 μm line and space resolution. After the exposure, the wafer was left in a laboratory for 3 hours, and then baked, whereby a good pattern was obtained.

Comparative Example 1 A positive resist solution having the following composition was prepared. 30% tetrahydropyranyl group-protected poly-p-hydroxystyrene: 2.0 g di-t-butoxycarbonylbisphenol A: 0.4 g triphenylsulfonium triflate: 0.1 g methoxypropanol: 12 ml This resist solution is dropped on the wafer surface. Then, after forming a film with a spin coater, pre-baking was performed at 100 ° C. for 2 minutes, and the thickness of the resist film was measured to be 0.95 μm
Met. The wafer was exposed to a line-and-space image at an exposure amount of 20 mJ / cm ^{2 using} a stepper having a numerical aperture of 0.5 and having a light source having a wavelength of 248 nm as a light source.
Baking at 2.degree. C. and development with 2.38% tetramethylammonium hydroxide gave a 0.3 .mu.m line and space resolution. After the exposure, the wafer was left in the laboratory for 3 hours, and then baked. As a result, no pattern was obtained due to the appearance of a hardly soluble layer on the surface.

Comparative Example 2 A positive resist solution having the following composition was prepared. 30% tetrahydropyranyl group-protected poly-p-hydroxystyrene: 2.0 g di-tert-butoxycarbonylbisphenol A: 0.4 g O- (p-toluenesulfonyl) -N-hydroxy-4,6-dimethylpyridone: 0 .1 g methoxypropanol: 12 ml The resist solution was dropped on the wafer surface, formed into a film by a spin coater, pre-baked at 100 ° C. for 2 minutes, and measured to have a thickness of 0.95 μm.
Met. The wafer was exposed to a line-and-space image at an exposure amount of 20 mJ / cm ^{2 using} a stepper having a numerical aperture of 0.5 and having a light source having a wavelength of 248 nm as a light source.
Baking at 2.degree. C. and development with 2.38% tetramethylammonium hydroxide did not yield any pattern.
A pattern was obtained when development was performed at a baking temperature of 140 ° C. However, when the film thickness of the unexposed part was measured,
0.70 μm, and dissolution of the unexposed portion was observed.

[0040]

The resist material of the present invention is highly sensitive to short-wavelength radiation, has high thermal stability, and is hardly affected by an alkaline compound entering from the environment, so that a high-precision pattern can be stably formed. be able to.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor, Sachiko Ogaya 3-2-1 Sakado, Takatsu-ku, Kawasaki City, Kanagawa Prefecture Shin-Etsu Chemical Co., Ltd. Corporate Research Center (56) References JP-A-4-134347 ( JP, A) JP-A-4-362647 (JP, A) JP-A-5-265214 (JP, A) JP-A-6-67433 (JP, A) JP-A-5-113667 (JP, A) JP-A-5-19478 (JP, A) JP-A-6-92909 (JP, A) JP-A-5-155942 (JP, A) JP-A-4-328552 (JP, A) (58) Fields investigated (Int) .Cl. ⁶ , DB name) G03F 7/004 G03F 7/039

Claims (3)

(57) [Claims] 1. A resist material comprising a glyoxime derivative represented by the following general formula (1) as a photoacid generator. Embedded image (Wherein, R ¹ and R ² each independently represent an alkyl group,
Represents a cycloalkyl group, an aryl group or a heteroaryl group, or R ¹ and R ² are bonded to each other to form a cyclic structure. R ³ represents an alkyl group, a cycloalkyl group, an aryl group or a heteroaryl group. ) 2. A positive resist material comprising (A) the glyoxime derivative according to claim 1, and (B) a polymer compound which is insoluble in aqueous alkali but becomes alkali-soluble by acid. 3. The glyoxime derivative according to claim 1, (B) a polymer compound soluble in an aqueous alkaline solution or soluble in an acid, and (C) at least one C—O—C that can be cleaved by an acid. A compound having a bond or C—O—Si bond, capable of inhibiting dissolution of the polymer compound of the component (B) in an aqueous alkaline solution, and losing this inhibitory ability by cleavage with an acid. Positive resist material.