JPH04156548A - Resist composition material - Google Patents

Abstract

PURPOSE:To obtain a composition material with high sensitivity against photo- decomposition by containing a polymer such as a t-butyl group or a benzyl group and a photo-active material generating acid when exposed to radiation. CONSTITUTION:When a highly isotactic polymer obtained by homopolymerizing a derivative of (meta) ester acrylate or hydroxylstyrene unstably branched against acid or copolymerizing it with other alpha,beta-ethylene unsaturated compounds is used, the sensitivity of a resist composition material is remarkably improved. A photo-active material generating acid when exposed to radiation and a photo- sensitizer are contained in a polymer made of (meta) ester acrylate with a group selected from among a t-butyl group, a benzyl group and the like as the essential monomer component and having an isotactic structure at least 70% or above. This resist composition material has very excellent sensitivity, it can be easily developed with little light quantity, and it can be applied to various purposes such as printing, a color filter, an integrated circuit and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a resist material comprising a highly sterically controlled polymer and a photoactive agent that generates an acid when exposed to radiation. More specifically, the present invention relates to a novel resist composition that has particularly excellent sensitivity and is useful for printing plates, photoresists for integrated circuits, photoresist materials for color filters, and the like.

[Prior Art] There are two types of resist compositions: negative type (the area irradiated with light is cured) and positive type (the area irradiated with light is eluted with a developer). Positive type has higher resolution than negative type, and is widely used in lithographic printing and resists for integrated circuits.

This positive resist composition generally utilizes a reaction in which a quinone diazide group is decomposed by light and converted into an indenecarboxylic acid via a ketene compound. This generated indenecarboxylic acid group makes it possible to elute into an alkaline solution.

Further, JP-A-59-45439 discloses a resist composition containing a compound that generates an acid upon irradiation, and a polymer that generates a phenol group or a carboxylic acid group when exposed to the acid.

[Problems to be Solved by the Invention] However, the above-mentioned quinonediazide-based resist composition has a problem in that it has low sensitivity to photodecomposition, and as a result, exposure time becomes long and work efficiency is poor. Further, the composition described in JP-A-59-45439 does not have sufficient sensitivity for applications such as printing, color filter resists, and integrated circuit resists.

An object of the present invention is to provide a new resist composition that is more sensitive to photodegradation.

[Means for solving the problem] In order to achieve the above object, a branched (meth)acrylate ester or a hydroxyl styrene derivative, which is unstable to acids, is homopolymerized using a polymerization technique that controls stereoregulatory properties. It has been discovered that the sensitivity of resist compositions can be dramatically improved by using highly isotactic polymers obtained by copolymerizing with other α,β-ethylenically unsaturated compounds, and in accordance with the present invention. It's arrived. .

That is, the present invention essentially requires a (meth)acrylic ester having a group selected from the group consisting of (a>t-butyl group, benzyl group, σ-methylbenzyl group, α,a-dimethylbenzyl group, and trityl group). (c) p-+-butoxycarbonyloxystyrene, p-t-butoxycarbonyloxystyrene, p-t-butoxy, carbonyl oxine-σ - a hydroquine rustyrene derivative selected from the group consisting of styrene, t-butyl-p-vinylbenchut and t-butyl-p-isopropenylphenyloxy/acetate as an essential monomer component, and having an isotactene structure of at least 70% % or more and (b) a photoactive agent that generates an acid when exposed to radiation, and the composition further contains a photosensitizer. .

The above-mentioned highly sterically regulated isotactic (co)polymer (a) or (
Anionic polymerization is suitable as a method for preparing c).
In particular, the living anionic polymerization method is most suitable. That is,
(Meth)acrylic acid ester monomer f: ld and droxyl styrene derivative monomer are essential monomer components when preparing the respective polymers (a) or (c), and other copolymerizable σ, Polymer (a) or (c) can be obtained by individual or copolymerization in the presence of a β-ethylenically unsaturated monomer.

The nistyl (meth)acrylate monomer for preparing the polymer (a) has a t-butyl group, a benzyl group, a-methylbenzyl group, an a+a-dimethylbenzyl group, a trityl group, and the like. Specific examples of such 7-mers include tert-butyl (meth)acrylate, benzyl (meth)acrylate, σ~methylbenzyl (meth)acrylate, α,α~dimethylbenzyl (meth)acrylate, and trityl (meth)acrylate. Examples include (meth)acrylic acid benzhydryl esters such as acrylate.

Specific examples of hydrogynestyrene derivatives for preparing the polymer (C) include p-tert-butoxyluponyloxynstyrene, p-tert-butoxycarbonyloxy-α-methylstyrene, tert-butyl-p −
Examples include vinyl benzoate, tert-butyl to p-isoprobenylphenyl quinoacetate-1.

Polymer (a, ) or (c) to be blended into the composition of the present invention
) may be a homopolymer or a copolymer. Therefore, the above (
One or more types of meth)acrylic acid ester monomers or hydroquine styrene derivative monomers can be used, and they may also be copolymerized with other copolymerizable C1β-ethylenically unsaturated monomers.

The other copolymerizable σ,β-ethylenically unsaturated septamers mentioned above are not particularly limited, and include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, and propyl (meth)acrylate. , (meth)acrylic acid esters such as isopropyl (meth)acrylate and phenyl (meth)acrylate, styrene, P-(m-)methylstyrene, σ-methylstyrene, p-(m-)chlorostyrene, p-( m-) Styrene derivatives such as bromostyrene, and the like. These are 1
More than one species can be used. The amount used is not particularly limited, but is preferably 0 to 30% by volume of the essential monomer. The polymerization initiator is not particularly limited as long as it can be used for anionic polymerization, and for example, organic alkali metal compounds, organic hydroxides, and the like can be used. Specific examples of organic alkali metal compounds include n-butyllithium, see-butyllithium, te
Examples include rt-butyllithium, cumylpotassium, cumylcenram, and the like. Further, specific examples of organic magnesium halide include 5ec-butylmagnesium chloride, LCrt-butylmagnesium chloride, benzylmagnesium bromide, 5ec-butylmagnesium bromide, tert-butylmagnesium bromide, benzylmagnesium bromide, etc.
One or more types of these may be used. The amount used is uniquely determined by the molecular weight of the polymer to be produced.

The polymerization reaction is carried out by stirring and mixing the above components in a solvent inert to the polymerization reaction at approximately -80°C to 100°C under an inert gas atmosphere or under reduced pressure (preferably under high vacuum). is common. Specific examples of solvents that can be used include aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene, and cyclohexane. Moreover, two or more kinds of solvents can be used in combination.

In addition, there is no particular restriction on the polymerization concentration, but 1 to 20
It is preferable to carry out within the range of wt%.

Further, the polymerization reaction time varies depending on the type of monomer used, the degree of polymerization, and the polymerization temperature, but for example, 1 minute to 72 minutes.
Usually it is time.

In addition, during the polymerization reaction, a tertiary polymer such as tetramethylethylenediamine, dibiperidinoethane, triethylamine, N-methylpyrrolidone, etc. is used to adjust the activity of the growing end.
Crown ethers such as 12-crown-4.15-crown-5 class amines, and salts having the same ion as the counter cation at the growth end, such as lithium chloride, sodium chloride, potassium chloride, cesium chloride, etc., are used. be able to. Although there is no particular restriction on the amount of these additives added, it is common to add them in an amount of 1 to 10 times the mole of the growth end. After the monomer is polymerized, the living end can be brought into contact with a proton donor, an alkylsilyl halide, etc. to inactivate it. Specific examples of proton donors include alcohols such as methanol, ethanol, and phenol, and water. Examples of alkylsilyl halides include trimethylsilyl chloride. One or more of these may be used.

Each of the polymers (a) or (c) obtained as described above has an isotactic structure of at least 70% or more, preferably 80% or more of the total structure. If it is less than 70%, the resist composition will not have sufficient sensitivity to photodecomposition, which is not preferable. The number average molecular weight of polymers (a) and (c) is 1°000 to 1,000,000, particularly 1.
0,000 to 200,000 is preferred. If the number average molecular weight is outside this range, not only will it be difficult to control the polymerization temperature and purify the polymer and solvent, but also it will not be possible to obtain sufficient membrane properties when forming a membrane, and the solubility in alkaline solutions will decrease. Problems such as this occur and are not desirable.

The resist composition of the present invention contains the above polymer (a) or (
In addition to c), it further contains a photoactive agent (b). The photoactivator (b) is highly sensitive to light irradiation, which attacks and decomposes the branched pendant groups that are unstable to acids, producing carpoxyl groups, phenolic acid groups, etc. This enables alkaline development. Onium salts are generally known as the photoactive agent (b) which generates an acid upon irradiation with light. Typical photoactivators (
Examples of b) include diaryliodonium salts, triarylsulfonium salts, triarylselenium salts, etc., and one or more of them can be used. Suitable counter-anions include complex metal halide compounds such as tetrafluoroborate, trifluoromethanesulfonate, hexafluoroantimonate, hexafluoroarsenate, and hexafluorophosphate. The resist composition of the present invention may further contain a photosensitizer in order to make it sensitive to longer wavelength light from ultraviolet rays to visible light. Any known photosensitizer can be used. For example, polycyclic aromatics such as pyrene and perylene may be used.

Other dyes such as acridine may also be used. These are 1
More than one species can be used.

In the composition of the resist composition of the present invention, polymers (a,
) or (c) l, whereas the photoactive agent (b) is 0°1-
50wt%, especially 1-30wt%, photosensitizer (if blended) 0.01-1Qwt%, especially 0.1-5vt
% is preferred. If the amount of the photoactive agent (b) exceeds 50 wt%, not only will sufficient film strength not be obtained, but it will also become economically unsuitable. The resist composition of the present invention is prepared using a polymer (
It is preferable to mix a) or (c) with the acid-generating photoactive agent (b) and, if necessary, a sensitizer, either as such or, if necessary, in a solvent in a cool, dark place. Solvents that can be used are ketones (eg, acetone, methyl ethyl ketone, chlorhexanone, etc.) and esters (eg, ethyl acetate, butyl acetate, ethylene glycol acetate).

Examples include ethers (eg, tetrahydrofuran, dioxane, etc.), and one or more of these can be used.

The resist composition of the present invention is first applied and dried on a support, exposed to light using a positive film, and then developed. Examples of the support include steel plates, treated glass plates, silicon wafers, and the like. Application is by rotation coating, wire bar coating,
It is carried out by a conventional method such as dip coating or roll coating. Light sources for light irradiation include ultra-high-pressure mercury lamps, high-pressure mercury lamps, metal halide lamps, xenon lamps, low-pressure mercury lamps, and the like. In the present invention, the irradiation amount is generally 1°OJ/
cm2 is sufficient. Development is done using an alkaline developer, for example,
Sodium hydroxide, potassium hydroxide, sodium carbonate,
Common materials such as potassium carbonate, sodium metasilicate, potassium metasilicate, etc. can be used. The concentration of this developer is preferably used in a range of 0.1 to 10% by weight.

[Effects of the Invention] The resist composition of the present invention has excellent sensitivity and can be easily developed with a small amount of light, and is suitably used in various applications such as printing, color filters, and integrated circuits.

[Examples] The present invention will be explained in more detail below with reference to Examples.
The present invention is not limited to these examples.

Preparation of Polymer (Preparation Example 1) The polymerization reaction was carried out under high vacuum using the breaker pull seal method (same as v4 Preparation Example 2). First, a benzene solution of 1,1-diphenylhexyllithium was placed in a polymerization container, and the inside of the container was thoroughly washed and then removed.

Next, at room temperature, toluene (148 ml) and a benzene solution of 1,1-diphenylhexyllithium (0,806 mmo
1.6.3 ml) and the container was cooled to -78°C. Next, tert-butyl methacrylate (140 mmo
A toluene solution (63 ml) of 1) was added to start the polymerization reaction. After stirring for 6 hours, methanol (2 ml) was added to stop the polymerization reaction. Next, after removing toluene from the reaction solution, it was redissolved in acetone and poured into a large amount of methanol/water mixed solution (1/Ivo 1%) to precipitate the product. After drying the product, it was purified by reprecipitation using an acetone/methanol-water mixed solvent system. The obtained polymer was 20.1 g (yield 100%) and Mn (GPC) = 4. O
X l O', Mw/M n = 1, 36, Tg =
It was 79°C.

The tufting tee of the polymer was determined as follows. That is, after dissolving 2.01 g of polymer in 50.0 g of benzene and 50.2 g of methanol, 1.0 g of trifluoromethanesulfonic acid was dissolved. oOml was added and reacted at 57°C for 10 hours. In IH, 845 cm-' of Bu'-0414
After confirming that the contraction vibration and the stretching vibration peak of gymnal dimethyl at 1365 cm-' disappeared, the reaction solution was precipitated in diethyl ether. The product was purified by reprecipitation with methanol/diethyl ether and further freeze-dried to obtain polymethacrylic acid. 0.200 g of this polymethacrylic acid was swollen in 5 ml of methanol and 20 ml of benzene, and 5 ml of a 10% hexane solution of trimethylsilyldiazomethane was added, followed by stirring overnight at room temperature. The reaction solution was poured into a large amount of n-hexane to precipitate a polymer. The reprecipitation purification was repeated several times in a benzene/hexane system and freeze-dried to obtain polymethyl methacrylate.
As a result of measuring C-NMR and calculating from the integral value of each peak, it was found that tufting tea had an intact structure of approximately 100%.

(Preparation Example 2) After thoroughly cleaning the inside of the device in the same manner as Preparation Example 1,
A benzene solution of 1.1-diphenylhexyllithium (2.41 mmol I, 18.8 ml) and toluene (150 ml) were placed in a reaction vessel, and the reaction vessel was cooled to -78°C. Then tert-methyl methacrylate (1
A toluene solution (50 ml) of 33 mmol) was added to initiate polymerization.

After stirring for 6 hours, methanol (2 ml) was added to stop the polymerization reaction. Next, the reaction solution was treated in the same manner as in Preparation Example 1. The obtained polymer was 19.5 g (yield 10
0%), Mn (GPC) = 2.0xlO', Mw/Mn
=1.25, Tg-77°C. Furthermore, when the toughness of the polymer was determined in the same manner as in Preparation Example 1, the isotact structure was approximately 100%.

(Preparation Example 3) After thoroughly cleaning the inside of the device in the same manner as Preparation Example 1,
A benzene solution of 1.1-diphenylhexyllithium (2.10 mmol, 16.4 ml) and toluene (885 ml) were placed in a reaction vessel, and the reaction vessel was cooled to -78°C. Then, tert-butyl methacrylate (
Polymerization was started by adding 91 mmol of toluene solution J (72 ml) and a toluene solution (41 ml) of methyl methacrylate (34 mmol). After stirring for 6 hours,
Methanol (2 ml) was added to stop the polymerization reaction. Next, the reaction solution was treated in the same manner as in Preparation Example 1. The polymer contained 16.5 g (100% yield) of Mn (GPC).
-1,2Xlo', Mw/Mn = 1.21.

Furthermore, in the same manner as in Preparation Example 1, the toughness of the polymer was
The result was 80% isotact structure, 16% heterotact structure, and 4% synsitact structure.

(Preparation Example 4) After thoroughly cleaning the inside of the device in the same manner as Preparation Example 1,
A benzene solution (0-231 mmo) of 1,1-diphenylhexyllithium was placed in a reaction vessel.

1.8 ml), toluene (84 rnl) and a toluene solution (20 ml) of tetramethylethylenediamine (0.48 mmol +) were added, and the reaction vessel was cooled to -78°C. Then, a toluene solution (36 ml) of tert-butoxycarbonyloxystyrene (21 mmol) was added.
) was added to initiate polymerization.

After stirring for 2 hours, methanol (2 ml) was added to stop the polymerization reaction. A large amount of methanol was poured into the reaction solution to precipitate the product. Thereafter, reprecipitation purification was performed using a benzene/methanol system. The polymer contained 5.0 g (yield 100%) of Mn.
(GPC)=2.8X I O', Mw/Mn-1,3
It was 4. The toughness of polymers is measured by C-NMR.
The result was 83% isotactic structure and 17% atactic structure.

(Comparative Preparation Example 1) 300 g of tert-butyl methacrylate was added to 183 g of methyl isobutyl ketone containing 12 g of azobisisobutyronitrile (AIBN), and the mixture was heated at 90°C in a nitrogen stream.
Thermal stirring was performed for IO hours.

Next, methyl isobutyl ketone was distilled off, acetone was added, and the solution was treated in the same manner as in Preparation Example 1.

The obtained polymer weighed 280 g (yield 93%) and contained Mn (
GPC)-o, 54xio', Ωw/Mn-190, T
g-68°C.

Furthermore, in the same manner as in Preparation Example 1, the toughness of the polymer was
As a result, it was found that 9% was an isotact structure, 37% was a -\telotact structure, and 54% was a non-diotact structure.

Preparation of resist composition (Example 1) 4 g of the polymer of Preparation Example 1 was dissolved in methyl isobutyl ketone so that the solid content was 2Qvt%, and triphenylsulfonium hexafluoro-antimonite was added to the polymer. Then, add 15vt%. Pour this solution onto a metal support for 2
By spin coating at 000 rpm, a resist film having a thickness of 2.0 microns was formed. The coating is 10
Dry at 5°C for 10 minutes. Next, apply a positive mask and irradiate with an ultra-high pressure mercury lamp at 0.6 J/cm2 or 1.2
The irradiation dose was 0J,/'Cm2. Then 1 more
After heating at 05°C for 10 minutes, development was performed at 50°C for 60 seconds with a 0.5% aqueous sodium hydroxide solution.

The obtained image was observed under a microscope and the developability was evaluated. The results are shown in Table-1.

(Example 2) A resist composition was prepared and developed in the same manner as in Example 1, except that the polymer of Preparation Example 2 was used instead of the polymer of Preparation Example 10. The developability evaluation results are shown in Table-1.

(Example 3) 0.5 g of the polymer of Preparation Example 4 was dissolved in methyl isobutyl ketone so that the solid content was 2 Q wt%, and triphenylsulfonium hexafluoroaledemonate was added at 15 wt% based on the polymer. % and further added 3w+% anthraquinone in the same manner as in Example 1, 2.0 μm.
A coating film was formed having a thickness of . The coating was dried at 105°C for 10 minutes. A positive mask was applied and exposure was performed using an ultra-high pressure mercury lamp at 400 mJ/cm2.

After further heating at 100°C for 5 minutes, a positive image was obtained by developing with a 1% sodium metasilicate aqueous solution at 35°C for 60 seconds.

(Comparative Example 1) A resist composition was prepared and developed in the same manner as in Example 1 except that the polymer of Comparative Preparation Example 1 was used instead of the polymer of Preparation Example 1. The developability evaluation results are shown in Table-1.

Table 1 Note) In Table 1, "x" indicates that there is not much change in the refractive index due to the exposed area changing to polymethacrylic acid, and "△" indicates that the exposed area swells in the developer. "Yes" and "○" respectively indicate that a good positive image can be obtained.

Patent applicant: Nippon Paint Co., Ltd.

Claims (1)

[Claims] 1. (a) (meth)acrylic acid having a group selected from the group consisting of t-butyl group, benzyl group, α-methylbenzyl group, α,α-dimethylbenzyl group, and trityl group A polymer containing an ester as an essential monomer component and having an isotactic structure of at least 70% and (
b) A resist composition containing a photoactive agent that generates an acid when exposed to radiation. 2. Claim 1, wherein the composition further contains a photosensitizer in an amount of 0.01 to 10% by weight based on the polymer (a).
Compositions as described. 3. Instead of polymer (a), (c) pt-butoxycarbonyloxystyrene, pt-butoxycarbonyloxy-α-styrene, t-butyl-p-vinylbenzoate and t-butyl-p- Claim 1 wherein the essential monomer component is a hydroxylstyrene derivative selected from the group consisting of isopropenylphenyloxyacetate.
or the resist composition described in 2.