JPH05257283A - Radiation-sensitive high molecular compound - Google Patents

Abstract

(57) [Summary] [Structure] The present invention is a radiation-sensitive polymer compound comprising (1) a phenolic hydroxyl group and (2) the following atomic group bonded to an aromatic ring. [Chemical 1] (Here, R ¹ and R ² are a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, and R ³ and R ⁴ are a hydrogen atom or a hydrocarbon group having a substituent or having no substituent and having 1 to 10 carbon atoms. It represents a hydrocarbon group, and a bond may be present between two members out of R ^{1 to} R ⁴ to form a ring containing a nitrogen atom), or a salt thereof with an organic acid or an inorganic acid. According to the present invention, a radiation-sensitive polymer compound which has high sensitivity and resolution characteristics, has excellent resistance to dry etching, does not require a post-exposure baking step, and is suitable as a resist having a large process latitude. Can be obtained.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel radiation-sensitive polymer compound. More specifically, it relates to a radiation-sensitive polymer compound which has excellent sensitivity characteristics and suitability for processes such as tri-etching, and is particularly suitable as a resist material for high-definition fine processing in semiconductor manufacturing processes. is there.

[0002]

2. Description of the Related Art Conventionally, in a pattern forming process in a manufacturing process of an integrated circuit, a composition composed of a novolac resin called photoresist and a quinonediazide type photosensitizer has been mainly used as a photosensitive material. In this case, a mercury lamp was used as the light source, and g-line (436 nm) was used among the bright lines. However, such pattern formation technology using near-ultraviolet rays and photoresist has an inherent limitation in resolution capability due to the diffraction phenomenon of light. Recently, it is necessary to meet the demand for pattern miniaturization accompanying high integration. Is getting harder. In order to further improve the drawing ability and obtain finer patterns, instead of g-line, i-line (365 nm) with a shorter wavelength or 308 nm (XeCl laser) or 248 nm (KrF) obtained from an excimer laser light source is used.
Laser) and other pattern forming techniques using wavelengths in the far ultraviolet region have been developed and are being used for the above purposes. Further, a pattern forming technique using X-rays or ion beams is also a powerful technique for miniaturization, and development of a resist corresponding to these new exposure light sources is an important issue.

The resists used in these new patterning techniques must meet several requirements. One of them is sensitivity. Since expensive equipment is used in these exposure techniques, high sensitivity is essential for industrial production in industrial production. Further, since these new technologies aim at finer patterns than the conventional technologies, the resolution characteristics of the resist are particularly important. Further, as other conditions required for the resist, it is important that the resist has a high resistance to dry etching and that the critical temperature at which thermal deformation does not occur after pattern formation is high. In addition, film forming properties and storage stability are required to obtain uniform processing accuracy.

Although many resists for i-line and far-ultraviolet rays by excimer laser have been proposed, which are attracting attention as a technique for replacing g-line for the time being, it is still known that they satisfy the above requirements in a well-balanced manner. Has not been done.

In recent years, a resist using a technique called a chemical amplification method has been studied in order to obtain high sensitivity. In this method, a compound that generates an acid upon exposure, such as a certain onium salt or organic halogen compound, is used as a resist component, and this acid is used as a catalyst, and the base resin in the exposed area undergoes a molecular chain scission or a It causes a chemical reaction such as a bridge bridge. For example, Japanese Unexamined Patent Publication (Kokai) No. 62-164045 proposes a resist comprising a compound that generates an acid by radiation and a thermosetting resin. In this method, an acid generated by exposure is used as a catalyst, and the resin in the exposed portion is insolubilized in a developing solvent by baking after the exposure. In principle, this type of method can increase the number of chemical reactions per unit exposure dose, resulting in high sensitivity, but the sensitivity changes depending on the degree of baking after exposure and the time until development. However, since the acid generated by exposure moves in the resist film over time, it is difficult to change the line width depending on the elapsed time during the process. In addition, there is generally a problem with storage stability, and there is much room for improvement for the purpose of industrial production.

[0006]

In view of the present situation as described above, the present inventors have conducted research to find a polymer compound that can be used as a high-performance resist material suitable for a new pattern formation technique, and arrived at the present invention. ..

That is, an object of the present invention is that a radiation-sensitive polymer having high sensitivity and resolution characteristics, excellent resistance to dry etching, no post-exposure baking step, and a large process latitude is suitable as a resist. To provide a compound. By selecting the chemical structure of the radiation-sensitive polymer compound of the present invention, in addition to ultraviolet rays in each wavelength range from near ultraviolet rays to far ultraviolet rays, an electron beam,
It is possible to obtain one that is compatible with the pattern forming technology using various light sources such as high-energy particle beams such as ion beams, X-rays, and synchrotron radiation, and has excellent storage stability.

[0008]

The object of the present invention is as follows.
This is achieved by a radiation-sensitive polymer compound characterized by containing the following two structures as essential components.

(1) Phenolic hydroxyl group (2) The following atomic group bonded to an aromatic ring

[Chemical 2] (Here, R ¹ and R ² are a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, and R ³ and R ⁴ are a hydrogen atom or a hydrocarbon group having a substituent or having no substituent and having 1 to 10 carbon atoms. It represents a hydrocarbon group, and R ^{1 to} R ⁴ may be partially or entirely the same, and a bond is present between two of R ^{1 to} R ⁴ to form a ring containing a nitrogen atom. Or an organic acid or an inorganic acid salt thereof.

The polymer compound of the present invention contains two essential structural elements in the molecule. One of the essential structural elements is a phenolic hydroxyl group. The type does not matter. A typical example is a hydroxyphenyl group, but examples include a hydroxynaphthyl group and a hydroxyanthryl group.
The number of hydroxyl groups bonded to the aromatic ring may be two or more, and the aromatic ring may include a hydrocarbon group such as a methyl group, a halogen group such as chlorine, and a substituent such as an alkyloxy group together with the hydroxyl group. I don't care. Also, a structure in which an aromatic ring having a hydroxyl group bonded thereto is condensed with a non-aromatic ring such as tetrahydrolane, hydroindene, and acenaphthene may be used.

The aromatic ring containing a hydroxy group may be present in the polymer chain in the form of a phenylene group or the like, or may be present in the side chain. With respect to the case where the aromatic ring is present in the side chain, specific examples of the existing form of the phenolic hydroxyl group are 2-hydroxyphenyl group, 3-hydroxyphenyl group, 4-hydroxyphenyl group, 2,4
-Dihydroxyphenyl group, 3,5-dihydroxyphenyl group, 2,4,6-trihydroxyphenyl group, 2-
Chloro-4-hydroxyphenyl group, 3-methyl-5-
Hydroxyphenyl group, 2,6-dimethyl-4-hydroxyphenyl group, 7- (4-hydroxy) indanyl group, 8- (5-hydroxy-1,2,3,4-tetrahydro) naphthyl group, 1- (2 -Hydroxy) naphthyl group, 1- (4-hydroxy) naphthyl group, 1- (2,4
-Dihydroxy) naphthyl group, 1- (2,6-dihydroxy) naphthyl group, 2- (4-hydroxy) naphthyl group, 2- (1,5-dihydroxy) naphthyl group, 1-
Examples thereof include a (10-hydroxy) anthryl group and a 9- (10-hydroxy) anthryl group.

Another one of the essential structural elements of the polymer compound of the present invention is the following atomic group bonded to an aromatic ring.

[Chemical 3] (Here, R ¹ and R ² are a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, and R ³ and R ⁴ are hydrogen atoms or a hydrocarbon group having 1 to 10 carbon atoms with or without a substituent. R ^{1 to} R ⁴ may be partially or wholly the same, and a bond may be present between two R ^{1 to} R ⁴ to form a ring containing a nitrogen atom. Good) or a salt thereof with an organic acid or an inorganic acid.

The benzene ring is the most typical aromatic ring. Further, a 5- or 6-membered heterocyclic structure such as a furan ring, a thiophene ring, a pyrrole ring or a pyridine ring can also be used. Further, a ring having a plurality of benzene rings or a structure in which a benzene ring and a heterocycle are condensed, such as a naphthalene ring, anthracene ring, phenanthrene ring, benzofuran ring, indole ring, quinoline ring, carbazole ring, etc. Needless to say, it is included in. Further, this aromatic ring may be present in the polymer chain or as a side chain, like the above-mentioned ring to which the phenolic hydroxyl group is bonded. Specific examples of the above amine structure bonded to the aromatic ring when present in the side chain include 4- (aminomethyl) phenyl group, 3- (methylaminomethyl) phenyl group, 4- (ethylaminomethyl)
Phenyl group, 2,4-bis (methylaminomethyl) phenyl group, 4- (isopropylaminomethyl) phenyl group, 3- (n-hexylaminomethyl) phenyl group, 4
-(Dimethylaminomethyl) phenyl group, 4- (diethylaminomethyl) phenyl group, 4- (diisopropylaminomethyl) phenyl group, 3- (diphenylaminomethyl) phenyl group, 4- (dicyclohexylaminomethyl) phenyl group, 4- (N-benzylaminomethyl) phenyl group, 4- (N, N-dibenzylaminomethyl) phenyl group, 4- [1- (benzylamino) ethyl] phenyl group, 4- (piperidinylmethyl) phenyl group, 4-
(Pyrrolylmethyl) phenyl group, 4- (carbazoylmethyl) phenyl group, 4- [1- (dimethylamino) ethyl] phenyl group, 4- (2-pyrrolidinyl) phenyl group, 3,5-bis (dimethylaminomethyl) Phenyl group, 2-chloro-4- (dimethylamino) phenyl group,
2,6-dimethyl-4- (diethylamino) phenyl group, 2,4,6-tris (dimethylaminomethyl) phenyl group, 1- (4-aminomethyl) naphthyl group, 2-
(4-methylaminomethyl) naphthyl group, 1- (4-dimethylaminomethyl) naphthyl group, 2- [1,4-bis (dimethylaminomethyl)] naphthyl group, 1- [2,6
-Bis (dimethylaminoethyl)] naphthyl group, 9-
(10-dimethylaminomethyl) anthryl group, 1-
[9,10-bis (diethylaminomethyl)] anthryl group, 2- (7-aminomethyl) phenanthryl group, 1
-(5-dimethylaminomethyl) acenaphthenyl group, 9
-(4-diethylaminomethyl) fluorenyl group, 9-
(4-aminomethyl) carbazoyl group, 1- (diphenylaminomethyl) naphthyl group and the like. These are only a few examples of structural elements constituting the polymer compound of the present invention. Further, when at least ^one of R ¹ and R ² is a hydrogen atom, relatively high sensitivity can be obtained. Further, this aromatic ring may contain a substituent such as a hydrocarbon group having 1 to 10 carbon atoms, a halogen or an alkoxy group. These amine structures can be salts of organic or inorganic acids. However, since the solubility of the polymer compound of the present invention in a solvent changes depending on the structure of a salt, it is necessary to select a soluble solvent and it is also necessary to select an optimum developing solution.

The polymer compound of the present invention is essential to contain the above two structural elements in the molecule.
The abundance ratio of the two structural elements in the polymer compound is not particularly limited, but is usually in the range of 1 to 90 amine (or salt) structures per 100 total phenol structures and amine (or salt) structures. .. A more preferable range is 10 to 70, and a particularly preferable range is 20 to 50. If the structure of the amine (or its salt) is too small, sufficient sensitivity cannot be obtained, and if it is too large, development with an alkaline aqueous solution becomes difficult and not only the use of an organic solvent becomes necessary but also the sensitivity decreases.

In the polymer compound of the present invention, a third other structural element can be added in addition to the above two essential structural elements. For example, you can improve performance by adding carboxyl group to increase solubility in alkaline aqueous solution to improve development speed, or adding naphthalene ring to control absorption of light energy during exposure, or increase dry etching resistance. Is.

There are basically two possible methods for producing the polymer compound of the present invention. One of them is a method of polymerizing or copolymerizing a monomer containing an essential structural element in the molecule. When two essential structural elements are contained in different monomers, it is necessary to copolymerize at least two kinds of monomers, and when one monomer contains two essential structural elements, homopolymerization is essential. The polymer compound of the invention is obtained. Another method of producing the polymer compound of the present invention is a method of polymerizing or copolymerizing a monomer having a chemical structure capable of inducing an essential structure, and then derivatizing the monomer into an essential structural element by a polymer reaction. In any of these two production methods, as described above, one kind or two or more kinds of other monomers not related to the essential structural element can be copolymerized.

The most widely used method for producing these is vinyl polymerization, but other known methods such as polycondensation and polyaddition, which are known as synthetic methods for polymer compounds, can be widely used. One of the simplest of these is the copolymerization of 4-hydroxystyrene and 4-dimethylaminomethylstyrene. At this time, 4-hydroxystyrene is replaced by 4-
It is also possible to induce the acetoxy group into a phenolic hydroxyl group after copolymerization with acetoxystyrene. Further, methyl methacrylate or styrene can be copolymerized as the third copolymerization component.

The third copolymerization component is used for controlling the performance of the polymer compound of the present invention, but if it is used in too much amount, the sensitivity is lowered. Examples of copolymerizable components that can be used in the case of vinyl polymerization include ethylene, propylene, acrylonitrile, vinyl chloride, maleic anhydride, acrylic acid, methacrylic acid, acrylic acid esters, methacrylic acid esters, vinyl acetate, styrene and the like. Examples include derivatives and vinyl ethers.

The molecular weight of the radiation-sensitive polymer compound of the present invention is not particularly limited, but usually 500 to 1,000,
It is in the range of 000. Particularly preferred range is 1,000
100 to 100,000. If the molecular weight is too large, the viscosity of the solution is high, the coating film is difficult, and the developability is lowered. Also, if the molecular weight is too small, the coating is weak,
Problems such as poor heat resistance after pattern formation occur.

The polymer compound of the present invention has high sensitivity to light, especially ultraviolet rays, as well as electromagnetic waves such as X-rays, synchrotron radiation and γ rays, and high-energy radiation such as electron beams, particle beams such as protons and metal ions. In particular, it is useful when used as a resist in fine processing of semiconductors, because an extremely high resolution can be obtained. As a resist, it has high dry etching resistance, and it can be developed with an alkaline aqueous solution that was used in the lithography process using a conventional photoresist.Because of its high storage stability, it is easy to obtain a certain quality of pattern accuracy. It has features. The polymer compound of the present invention is suitable not only as a photoresist but also for lithography using electron beams, X-rays and the like. When using it as a photo resist, it is necessary to pay attention to the light absorption of the polymer compound. When coated as a resist, it is difficult to obtain sufficient sensitivity if the amount of light used for lithography is too small, and if the amount of light absorbed is too strong, a large amount of light is absorbed on the surface of the coating and the difference in the degree of exposure between the surface and the bottom surface Since it is large, the cross-sectional shape of the pattern after development tends to cause a so-called reverse taper.
Generally, when light with a relatively long wavelength of 300 nm or longer is used, the aromatic ring in the polymer compound uses a long conjugated system such as a condensed ring structure such as a naphthalene ring or anthracene ring or a biphenyl structure to enhance absorption to some extent. It is easier to obtain sensitivity. Benzene ring when the wavelength is relatively short around 250 nm,
It is advantageous to utilize aromatic rings up to the naphthalene ring.

The polymer compound of the present invention has reduced solubility in a solvent upon exposure to these radiations. In particular, when it is soluble in an alkaline aqueous solution, development with an alkaline aqueous solution is possible by utilizing the change in dissolution performance due to exposure.

Although the mechanism of expression of this sensitivity is not sufficiently clear at present, a chemical reaction occurs between two essential structural elements by exposure, the phenolic hydroxyl group is blocked, and a chemical bond is generated between the structural elements. It is believed that the increase in the amount of water causes a synergistic decrease in the dissolution rate, especially in an alkaline aqueous solution. Note that development with an organic solvent is also possible without using an alkaline aqueous solution, and this method must be used when the original polymer compound is insoluble in the alkaline aqueous solution.

The fine pattern using the polymer compound of the present invention as a resist is formed as follows.

The polymer compound of the present invention alone or together with other additives as necessary is dissolved in an organic solvent, filtered, and then coated on a silicon wafer, a chrome mask substrate or another substrate to obtain a uniform mixture. Form a coating film. Solvents for the coating film include dioxane, tetrahydrofuran, ethers such as ethylene glycol dimethyl ether, chlorinated hydrocarbons such as chlorobenzene and trichloroethylene, n-butyl acetate, isoamyl acetate, cellosolve acetate, methyl cellosolve acetate, ethyl cellosolve acetate, acetic acid. Carboxylic acid esters such as butyl and ethyl lactate, dimethylacetamide, dimethylformamide, N
-Aprotic polar solvents such as pyrrolidone and ketones such as cyclohexanone, methyl isobutyl ketone and diacetone alcohol are mainly used. These can be used alone or, if necessary, mixed to enhance the coating property. Hydrocarbons and alcohols, which are themselves nonsolvents to the constituents, may be used as a part of the solvent. Further, in addition to the resist composition, a surfactant for improving the coating property, a certain dye for improving the pattern shape, and other storage stabilizers can be added to this solution. The concentration of the resist composition in the solution is usually 5 to 50% and is determined depending on the required film thickness and the method and conditions of the coating film. Spin coating or spray coating is often used for the coating film.

After the coating film, if necessary, a baking treatment is performed to expose a desired portion of the thin film. Electron beams, X-rays, ultraviolet rays, synchrotron radiation, ion beams, etc. are used as exposure light sources for drawing. An exposure method in which a mask is interposed between the light source and the surface to be exposed so that energy can reach the film surface according to the desired pattern, and the exposure energy is made into a narrow beam to draw the desired pattern on the coating surface. The exposure method is known. The latter method is possible when using an electron beam or an ion beam as the light source. The development is generally a dipping or spraying method. An alkaline aqueous solution is used as the developing solution. For example, alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, trisodium phosphate, and sodium borate, weak alkali metal salts and tetramethylammonium hydroxide, tetraethylammonium hydroxide, Examples thereof include aqueous solutions of quaternary ammonium hydroxide such as tetrabutylammonium hydroxide and choline. In the case of a particularly soluble polymer compound, aqueous ammonia or an aqueous solution of amines such as n-propylamine, diethylamine, β-picoline, piperidine and collidine may be used. If necessary, quaternary ammonium salts, other salts, alcohols, surfactants, etc. may be added to these developers. Known methods can be used for the rinse and the post-baking.

The radiation-sensitive polymer compound of the present invention is excellent in storage stability because it does not contain a structure unstable to heat or visible light even if it is dissolved in a coating solvent and stored.
Especially when stored for a long period of time, if the container is sealed with nitrogen gas and stored in a cool dark place, the change in performance is extremely small.
Since it is virtually insensitive to visible light except for those designed for light in the near-ultraviolet or visible wavelengths, it can be handled in the bright and does not require a yellow lamp. Due to such stability, the polymer compound of the present invention can always exhibit a certain image forming property, which is extremely advantageous in the process of industrial production.

[0027]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited thereto.

Example 1 8.0 g of 3-acetoxystyrene, 2.0 g of 3- (dimethylaminomethyl) styrene and 1.0 g of azobisisobutyronitrile were mixed and dissolved in 40 ml of toluene, and the mixture was dissolved in nitrogen. Polymerization was carried out at 65 ° C. for 46 hours. After the completion of the polymerization time, the reaction mixture was poured into 400 ml of hexane to separate the polymer, and the polymer was vacuum dried. Further, the obtained copolymer was dissolved in 100 ml of dioxane, 20 ml of hydrazine hydrate was added dropwise to this solution, and the mixture was stirred at room temperature for 6 hours for deacetylation reaction. The reaction mixture was poured into 300 ml of hexane to precipitate the polymer, which was filtered, washed with water and dried to give 6.5 g of 3-hydroxystyrene-3- (dimethylaminomethyl) styrene copolymer having a weight average molecular weight of about 6,000. Obtained.

1.0 g of this copolymer was dissolved in 4.2 g of methyl cellosolve acetate to prepare a resist solution. This is spin-coated on a silicon wafer according to a conventional method, and the temperature is 90 ° C.
A pre-baking treatment was performed for 20 minutes in the above air oven to obtain a coating film having a film thickness of 0.98 μm. An exposure test was performed at 254 nm using a 500 W Xe-Hg lamp as a light source and an interference filter. A large number of small spots were exposed on the coating film surface of the resist by changing the exposure time. After exposure, develop with 0.20N tetramethylammonium hydroxide aqueous solution,
After the post-baking treatment was performed at 0 ° C. for 20 minutes, the film thickness of each small spot was measured, and the relationship with the exposure amount was examined to prepare a sensitivity curve. The exposure dose corresponding to a residual film rate of 50% on the sensitivity curve was 16 mJ / cm ² .

Example 2 An average molecular weight of about 8.0 consisting of 84 mol% of 3-hydroxystyrene and 16 mol% of 4- (diethylaminomethyl) styrene synthesized according to the method described in Example 1.
Copolymer No. 00 was coated on a chromium substrate using methyl cellosolve acetate as a solvent to obtain a coating film having a thickness of 0.85 μm. The sensitivity characteristics of this coating film were measured. Fifty
Exposure was performed by the method described in Example 1 using an exposure apparatus having a 0 W Xe-Hg lamp as a light source and a cold mirror having a reflection peak near 290 nm, and developed with a 0.25 N tetramethylammonium aqueous solution. However, the exposure time corresponding to the residual film ratio of 50% was 2.5 seconds.

Example 3 A copolymer having a weight average molecular weight of about 12,000 consisting of 82 mol% of 4-hydroxystyrene and 18 mol% of 4- (benzylaminomethyl) styrene was dissolved in ethyl acetate cellosolve at a concentration of 15%. It was spin-coated on a silicon wafer to obtain a coating film having a thickness of 0.70 μm. The sensitivity to 254 nm far-ultraviolet light was measured according to the method described in Example 1. Sensitivity corresponding to 50% residual film rate is 18.5 mJ /
It was cm ² .

Example 4 Prepared according to the method described in Example 1 using 9.0 g of 4-acetoxystyrene and 1.0 g of 4- (diethylaminomethyl) styrene with 0.10 g of asobisisobutyronitrile as an initiator. 4-hydroxystyrene and 4-
A copolymer with (diethylaminomethyl) styrene having a weight average molecular weight of about 40,000 was dissolved in methyl cellosolve acetate. The polymer concentration of the solution was 10%. After coating on a silicon wafer to form a coating film having a thickness of 1.0 μm and baking on a hot plate at 120 ° C. for 120 seconds, the method 2 described in Example 1 was applied.
A deep UV exposure of 54 nm was performed. When developed with a 0.13 N tetramethylammonium hydroxide aqueous solution, the sensitivity giving a residual film rate of 50% was 9 mJ / cm ² .

Example 5 The method described in Example 1 using 8.0 g of 4-acetoxystyrene and 2.0 g of 4- (dimethylaminomethyl) styrene as raw material monomers and 1.0 g of azobisisobutyronitrile as an initiator. The copolymer obtained by polymerization at 65 ° C. for 48 hours was treated in the same manner as in Example 1 to obtain 6.8 g of a copolymer of 4-hydroxystyrene and 4- (dimethylaminomethyl) styrene. When exposure was performed by the method described in Example 1 and development was performed with a 0.15N tetramethylammonium hydroxide aqueous solution, the sensitivity at a 50% residual film rate was 10 mJ / cm ² . Also, this coating has a wavelength of 2
The transmittance for 54 nm far-ultraviolet light is 4 when the film thickness is 1 μm.
It was 2%.

When the test pattern was exposed with a KrF excimer laser (248 nm), a line and space having a line width of 0.35 μm was clearly resolved when the coating film having a film thickness of 1 μm was exposed at 100 mJ / cm ² .

Example 6 9.0 g of 4-acetoxystyrene and 3-chloro-4
1.0 g of-(dimethylaminomethyl) styrene was mixed and dissolved in 60 ml of benzene together with 1.0 g of azobisisobutyronitrile, and polymerized at 65 ° C for 40 hours in a nitrogen atmosphere. The reaction mixture was treated according to the method described in Example 1 to give 4-hydroxystyrene having a weight average molecular weight of about 7,000 = 3-chloro-4- (dimethylaminomethyl).
6.5 g of a styrene copolymer was obtained. This copolymer was dissolved in cyclohexanone to a concentration of 25% to prepare a resist solution, which was spin-coated on a silicon wafer to obtain a coating film having a thickness of 0.95 μm. Exposure according to the method described in Example 1 and development with a 0.16N tetramethylammonium hydroxide aqueous solution gave a 50% residual film sensitivity of 14 mJ / cm ² .

Example 7 A copolymer of 72 mol% 4-hydroxystyrene and 28 mol% 4- (dimethylaminomethyl) styrene was made into a 20% solution of ethyl cellosolve acetate, and then a calculated amount of acetic acid was added dropwise. The dimethylaminomethyl group was converted to acetate. This resist solution was spin-coated on a silicon wafer to form a resist film having a thickness of 1.01 μm. Exposing to 254 nm deep UV radiation as described in Example 1,
When developed with 0.23N tetramethylammonium hydroxide, the 50% residual film sensitivity was 9 mJ / cm ² .

Example 8 4-hydroxy-1-vinylnaphthalene 37 mol%, 4
A ternary copolymer consisting of 43 mol% of hydroxystyrene and 20 mol% of 4- (dimethylaminomethyl) styrene and having an intrinsic viscosity of 0.070 measured in dioxane at 25 ° C., as a 20% solution of ethyl cellosolve acetate, A silicon wafer was spin-coated to form a coating film having a thickness of 0.90 μm, and the sensitivity was measured according to the method described in Example 1. An aqueous solution of 0.29N tetramethylammonium hydroxide was used for development. The 50% residual film sensitivity was 20 mJ / cm ² . Moreover, when the interference filter is changed and the sensitivity to 280 nm far ultraviolet rays is measured, it is 13
It was mJ / cm ² .

EXAMPLE 9 A copolymer having 91% by mole of 4-hydroxystyrene and 9% by mole of 4-dimethylaminomethyl-1-naphthol and having an intrinsic viscosity of 0.11 measured at 25 ° C. in dioxane was treated with methyl cellosolve acetate. Dissolve in silicon wafer
A coating film having a film thickness of 1.10 μm was obtained by coating on the above. Xe
-Using an Hg lamp as a light source and an interference filter,
Exposure was performed with far-ultraviolet light of 9 nm, and the sensitivity was measured by the method described in Example 1. For development, a 0.25N tetramethylammonium hydroxide aqueous solution was used. The 50% residual film sensitivity was 8 mJ / cm ² .

Example 10 90% by mol of 4-hydroxystyrene and 10% by mol of 9-dimethylaminomethyl-10-vinylanthracene, having an intrinsic viscosity of 0.
The sensitivity of the copolymer of No. 09 was measured according to the method described in Example 1. Chlorobenzene was used as the coating solvent, and the baking treatment was performed using a hot plate at 110 ° C. for 120 seconds. For development, a 0.30N tetramethylammonium hydroxide aqueous solution was used. As a result of exposure to 365 nm ultraviolet light using an interference filter, the exposure amount corresponding to a residual film rate of 50% was 18 mJ / cm ² .

Example 11 Using a ternary copolymer consisting of 76 mol% 4-hydroxystyrene, 18 mol% 4- (dimethylaminomethyl) styrene and 6 mol% styrene at 254 nm according to the method described in Example 1. Sensitivity measurements were performed. The 50% residual film sensitivity was 11 mJ / cm ² when a 0.30 N tetramethylammonium hydroxide aqueous solution having a film thickness of 0.85 μm was used as a developing solution.

Example 12 The copolymer of 4-hydroxystyrene and 4- (diethylaminomethyl) styrene described in Example 4 was spin-coated on a silicon wafer and prebaked on a hot plate at 100 ° C. for 120 seconds. A coating film having a thickness of 0.70 μm was obtained. A large number of small spots having different exposure amounts were exposed on this film surface by using an electron beam with an acceleration voltage of 20 KV. After the exposure, the film was developed with a 0.13N tetramethylammonium hydroxide aqueous solution, washed with water and dried, and then the film thickness of each small spot was measured, and a sensitivity curve was created from the relationship with the exposure amount. The exposure amount corresponding to the residual film rate of 50% on the sensitivity curve was 6 μC / cm ² .

Example 13 90% by mol of 4-hydroxy-isopropenylbenzene,
A copolymer consisting of 10 mol% of 4- (methylaminomethyl) styrene was coated on a silicon wafer to give a film thickness of 0.
The 81 μm coating film was exposed to deep ultraviolet rays of 254 nm by the method described in Example 1 to measure the sensitivity. A 0.45N tetramethylammonium hydroxide aqueous solution was used as a developing solution. The amount of exposure when the remaining film ratio is 50% is 35 m.
It was J / cm ² .

Example 14 A copolymer of 88 mol% 4-hydroxystyrene and 12 mol% 3,5-bis (dimethylaminomethyl) styrene having a weight average molecular weight of about 7,000 was prepared as a methyl acetate cellosolve solution on a silicon wafer. Was spin-coated on to prepare a coating film having a film thickness of 0.95 μm. Exposure was performed by the method described in Example 1, and further development processing was performed with a 0.16N tetramethylammonium hydroxide aqueous solution. The exposure dose corresponding to the 50% residual film rate was 13 mJ / cm ² .

Example 15 A copolymer consisting of 83 mol% 4-hydroxystyrene and 17 mol% of a monomer having the following structural formula:

[Chemical 4] A resist solution having a concentration of 20% was prepared by dissolving it in cyclohexanone. The sensitivity characteristics were measured according to the method described in Example 1. The film thickness was 1.00 μm, and the developing solution used was an aqueous solution of 0.25N tetramethylammonium hydroxide. The 50% residual film sensitivity was 28 mJ / cm ² .

Example 16 For the copolymer consisting of 87 mol% of 4-hydroxystyrene and 13 mol% of vinyl 4- (dimethylaminomethyl) cinnamate, the sensitivity characteristic at 365 nm was measured by the method of Example 1. I did it. 5 at a film thickness of 0.56 μm
The 0% residual film sensitivity was 10 mJ / cm ² .

Example 17 A copolymer consisting of 53 mol% 3,5-dihydroxystyrene, 25 mol% 4- (dimethylaminomethyl) styrene and 22 mol% methyl methacrylate was dissolved in cyclohexanone and coated on a chromium substrate. Then, prebaking is performed in an air oven at 70 ° C for 20 minutes to obtain a film thickness of 0.8.
A coating film of 5 μm was obtained. An exposure test was conducted according to the method described in Example 1 with far ultraviolet light of 254 nm. After exposure 0.
Development was carried out with a 52N aqueous solution of tetramethylammonium hydroxide to obtain a 50% residual film sensitivity of 75 mJ / cm ² .

Example 18 A copolymer consisting of 73 mol% of 4-hydroxystyrene, 3 mol% of 2-allylphenol and 24 mol% of 4- (diethylaminomethyl) styrene is composed of 65% of ethyl cellosolve acetate and 35% of ethyl acetate. A coating film having a film thickness of 0.60 μm on a silicon wafer dissolved in a mixed solvent was subjected to an exposure test at 500 W of Xe-Hg through a cold mirror having a reflection peak of 290 nm. A sensitivity curve was created from the relationship. The exposure time corresponding to a residual film rate of 50% was 1.1 seconds.

Claims (1)

[Claims] 1. A radiation-sensitive polymer compound comprising the following two chemical structures as essential constituents. (1) Phenolic hydroxyl group (2) The following atomic group bonded to an aromatic ring (Here, R ¹ and R ² are a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, and R ³ and R ⁴ are a hydrogen atom or a hydrocarbon group having a substituent or having no substituent and having 1 to 10 carbon atoms. It represents a hydrocarbon group, and R ^{1 to} R ⁴ may be partially or entirely the same, and a bond is present between two of R ^{1 to} R ⁴ to form a ring containing a nitrogen atom. Or an organic acid or an inorganic acid salt thereof.