JPH02296801A - Photosensitive composition - Google Patents

Abstract

PURPOSE:To obtain a photosensitive composition improved in sensitivity to deep UV and resistance to oxygen reactive ion etching by mixing a specified polymer with an oxo acid ester compound and a compound which can generate an acid upon exposure to light. CONSTITUTION:A photosensitive composition is obtained by dissolving 100 pts.wt. alkali-soluble polymer having a phenolic skeleton (e.g. phenol novolak resin), 1-500 pts.wt. oxo acid ester compound (e.g. methyl 2-formylpropionate and 0.01-0.05wt.% compound which can generate an acid upon irradiation with light (e.g. iodoniumtrifluoromethane sulfonate). This composition is applied to a substrate, dried, exposed to light by irradiation with 1-10J/cm<2> of deep UV through a mask having any desired pattern, developed with an aqueous alkali solution (e.g. aqueous tetramethylammonium halide oxide solution), and formed into any desired resist pattern by dissolving the unexposed area.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to a photosensitive composition, in particular deepUv
It relates to a photosensitive composition that is sensitive to light.

(Prior Art) Photosensitive resins are widely used in the field of electronic components that require various types of microfabrication, including semiconductor integrated circuits. In particular, electronic devices are becoming more multi-functional.

In order to achieve high-density integration as the density increases, finer patterns are required. As an exposure device used for pattern formation, there is a step-and-repeat reduction projection type mask aligner commonly called a stepper. Light sources used in such devices include mercury lamp g-line (wavelength 436 nm), h-line (wavelength 405 nm), i
(wavelength 365 nm), XeF as an excimer laser
(Wavelength 351 nga), Xe(J! (Wavelength 308 nga)
nm), KrF (wavelength 248nm), KrCQ (wavelength 222n+m), ArF (wavelength 193nm), F
, (wavelength: 157 nm), etc. In order to form fine patterns, the shorter the wavelength of the light source, the better, and a resist that is sensitive to deep UV light such as an excimer laser is desired.

As photosensitive resins for the above-mentioned excimer laser, photosensitive compositions consisting of acrylic polymers such as polymethyl methacrylate (PMMA) and polygel tar maleimide (PGMI) or polymers containing phenol and azide photosensitizers have conventionally been used. It has been known. However, the former photosensitive resin has low sensitivity to excimer lasers,
In addition, there was a problem that the dry etching resistance was inferior.

Further, although the latter photosensitive composition has excellent sensitivity and dry etching resistance, it has the problem that the formed pattern is an inverted triangle, making it difficult to control the exposure and development steps.

Furthermore, problems have arisen in various exposure methods as the minimum dimension is reduced.9 For example, in light exposure, the interference effect of reflected light due to the step difference on the semiconductor substrate has a large impact on dimensional accuracy. give. On the other hand, in electron beam exposure, there is a problem in that it is not possible to increase the height-to-width ratio of a fine resist pattern due to the proximity effect caused by backscattering of electrons.

A multilayer resist system has been developed as a method to solve the above-mentioned problems. For such multilayer resist systems, see Solid State Technology, 7
4 (1981) [5olid 5tate Tac
hnology, 74 (1981)], and many other studies regarding the system have also been published.

Currently, a method that has been widely attempted within the shell is a three-layer resist system, in which the bottom layer has the role of flattening the steps of the semiconductor substrate and preventing reflection from the substrate, and the bottom layer is etched. It consists of an intermediate layer that functions as a mask for the photosensitive material, and an uppermost layer that serves as a photosensitive layer. However, although this three-layer resist system has the advantage of being able to perform finer patterning than the single-layer resist method, it has the problem of increasing the number of steps required to form a pattern. That is, since there is no resist that satisfies both photosensitivity to radiation such as deep UV and resistance to reactive ion etching by oxygen plasma, these functions are provided in separate layers, resulting in a reduction in the number of steps. To increase.

(Problems to be Solved by the Invention) The present invention has been made to solve the above-mentioned conventional problems. The present invention aims to provide a photosensitive composition that has high tolerance during development and allows formation of a fine pattern having a good cross-sectional shape. Furthermore, we would like to provide a silicon-containing photosensitive composition that is sensitive to radiation with short wavelengths such as daep UV, has excellent resistance to oxygen reactive ion etching (oxygen RIE resistance), and can be developed with an alkaline aqueous solution. That is.

[Structure of the invention]

(Means and actions for solving problems) The present invention is.

■ Alkali-soluble polymer with phenol skeleton.

A photosensitive composition comprising: an oxoacid ester compound; and a compound that generates an acid when exposed to light;

In the present invention, examples of the alkali-soluble polymer having a phenol skeleton include phenol novolak resins and substituted phenol novolak resins.

Poly(p-vinylphenol), a copolymer of p-isopropenylphenol and acrylonitrile (copolymerization ratio 1:
1), copolymer of p-isopropenylphenol and styrene (copolymerization ratio 1:1), copolymer of p-vinylphenol and methyl methacrylate (copolymerization ratio 1:1), p-
Copolymer of vinylphenol and styrene (copolymerization ratio 1:
1) etc.

In addition, the oxoacid ester compounds of the present invention include ethyl formyl acetate, methyl 2-formylpropionate,
Methyl 3-formylpropionate.

Methyl 3-formylbutyrate, methyl 4-formylbutyrate, 5
-Methyl formylvalerate, methyl 6-formylhexanoate, methyl 7-formylhebutanoate, methyl 8-formyloctanoate, ethyl 9-formylnonanoate, ethyl diformylacetate, methyl cis-3-formyl acrylate, trans-3 -Ethyl formyl acrylate, diethyl formyl malonate, diethyl formyl succinate, 2-
Diethyl ethyl-3-formylsuccinate, ethyl 2-formylglutaconate, diethyl (2-formylethyl)malonate, diethyl (2,2-jethoxyethyl)methylmalonate, 3,3-jethoxypropylmalonic acid Examples include diethyl, diethyl 2,3-diformylsuccinate, and the like.

Next, as keto acid ester compounds containing a keto group and an acid ester, α-keto ester compounds include ethyl pyruvate, methyl 2-oxobutyrate, methyl 2-oxoisovalerate, ethyl 2-oxovalerate, 2-oxo Ethyl hexanoate, ethyl 4-methyl-2-oxovalerate, 3
Examples include ethyl-methyl-2-oxovalerate, ethyl 3,3-dimethyl-2-oxobutyrate, and examples of β-ketoester compounds include methyl acetoacetate, ethyl acetoacetate, tert-butyl acetoacetate, etc. . Furthermore, as a γ-ketoester compound.

Ethyl levulinate, methyl 4-oxohexanoate, 3-
Ethyl methyl levulinate, methyl 2-methyl levulinate, methyl 2-methyl levulinate, methyl 4-oxoheptanoate, methyl 4-oxooctanoate, ethyl 4-oxononanoate, methyl 4-oxodecanoate, methyl mesitoate, 3 , ethyl 3-dimethyllevulinic acid, methyl 5,5-dimethyllevulinic acid, ethyl 3,5-dimethyllevulinic acid, methyl lyhesterate, methyl lithinate, etc., and as the δ-keto ester compound, 5-oxohexane Ethyl acid, ethyl gelonate.

Methyl isogelonate, ethyl 5-oxodecanoate, 3-
Ethyl isopropyl-6-oxoheptanoate.

Examples thereof include methyl 3.7-dimethyl-6-oxo n-octanoate and methyl lactate.

Furthermore, as unsaturated ketoester compounds, 3゜3-jethoxyacrylate, ethyl 2-chloro-3,3-jethoxyacrylate, ethyl 2-methyleneacetoacetate, ethyl 2-ethylideneacetoacetate, ethyl isopropylideneacetoacetate , ethyl 3-acetylacrylate,
Can you name ethyl 4-oxo-2-hexenoate, ethyl lycanate, etc.? Also. Examples of aldehyde ketoester compounds include ethyl 1,2-dioxopropionate, ethyl mucoxychlorate, and ethyl mucoxybromate.

Examples include ethyl glyoxylylacetate, ethyl 3-glyoxylylpropionate, and ethyl formylacetoacetate.

The α-diketoester compounds include ethyl 2゜3-dioxobutyrate, ethyl 3,4-dioxovalerate, 5
-Methyl-3,4-dioxohexanoate, ethyl diketostearate, methyl 13.14-dioxobhenate, etc.; β-diketoester compounds include ethyl acetopyruvate, 2,4-dioxohexanoate, etc. Examples include ethyl hexanoate and 2°4-dioxohebbutanoic acid.

Examples of diacylacetoacetate compounds include ethyl diacetoacetate, ethyl 2-propionyl acetoacetate, methyl 2-butyrylacetoacetate, and γ-diketo ester compounds include ethyl 2-acetonylacetoacetate, ethyl 5-7cetonylleprinate, and 3-acetyl ethyl acetoacetate. Ethyl levulinate, 3
-Ethyl acetyl-2-methyllevulinate, methyl 4-acetyl-5-oxohexanoate, ethyl 4-acetoacetoacetate, methyl 2,2-dimethyl-3,5-dioxohexanoate, as unsaturated diketocarboxylic acid ester compound , methyl 5-methyl-3,4-dioxo-5-hexenoate, ethyl 4,7-thioxo-2-octenoate, 2
, ethyl 4-diketo-6-methyl-5-heptenoate, as triketocarboxylic acid ester compounds, ethyl 3-acetyl-2,4-oxovalerate, ethyl pyruvilpyruvate, 2-acetyl-3,5- As ethyl dioxohexanoate and ketodicarboxylic acid ester compounds, ethyl oxomalonate, diethyl diacetoxymalonate, diethyl oxalacetate, diethyl methyloxalacetate, diethyl ethyloxalacetate, diethyl n-propyloxalate, n-butyl, diethyl oxalacetate. , diethyl dimethyloxalacetate, diethyl ethylmethyloxalacetate, diethyl oxalacetate, dimethyl dioxosuccinate, diethyl 2-oxogludarate, dimethyl acetonedicarboxylate, ethyl 4-cyanoacetoacetate, 4
-ethyl cyanogen-2,2-dimethylacetoacetate, diethyl 2-oxoadipate, dimethyl 3-oxoadipate, diethyl 2-ethyl-3-oxoadipate, 2,
Diethyl 3-dioxoadipate, diethyl 3,4-dioxoadipate, dimethyl 2,5-dioxoadipate, 5゜5-dimethyl-dimethyl 2,4-dioxoadipate, 5,5-diethyl- Diethyl 2,4-dioxoadipate, diethyl 3-oxopimelate, diethyl ketipate, diethyl 4-oxopimelate, diethyl xanthothieridonate, diethyl phoronate, diethyl 2-oxosperate, diethyl 3-oxosperate,
Examples include diethyl 4-oxosperate, ethyl 5-oxoazelaate, ethyl 5-oxosebacate, ethyl anemonoleate, ethyl 5-oxypyrunate, diethyl 5,12-dioxoazate, and the like.

Furthermore, the acyldicarboxylic acid ester compounds include diethyl acetylmalonate, diethyl acetylsuccinate, dimethyl 2-acetyl-2-methylsuccinate, diethyl 2-acetyl-2°3-dimethylsuccinate, diethyl 2,3-diacetylsuccinate, diethyl acid, diethyl 2-acetylglutarate, diethyl 2,4-diacetylglutarate, dimethyl 2-acetyl-3-oxoadipate, diethyl 2-acetyl-4-oxoadipate,
As the unsaturated ketodicarboxylic acid ester, diethyl 2-methylene-4-oxoglutarate.

Diethyl oxalfurotonate, 2,5-dioxo-3-
Ethyl hexenedioate, 4-oxo-2,5-hebutadienioic acid, ethyl maleylacetoacetate, diethyl fumasolacetoacetate, diethyl diacetofumarate, ethyl acetoacetate, ketopolycarboxylic acid esters include triethyl oxalmalonate, 2-cyan-2 -Iminoethane-
Diethyl 1,1-dicarboxylate, diethyl 2-cyanoxaneacetate, oxalylmalononitrile ethyl ester, triethyl 2-oxopropane-1,1,3-tricarboxylate, triethyl oxalsuccinate, 4-oxopentane-1,2,3- Triethyl tricarboxylate, 3-
Triethyl acetyltricarboxylate and oxyoxo acid esters include ethyl oxypyruvate, ethyl 3-oxy-2-oxobutyrate, ethyl 4-oxy-2-oxobutyrate, ethyl 2-oxyacetoacetate, ethyl 4-oxyacetoacetate, 3- Ethyl formyl-3-oxypropionate, ethyl 2,4-dioxyacetoacetate, methyl leuronate, 4-oxy-2-oxovalerate, ethyl 2-oxy-2-methylacetoacetate, 4-oxy-2゜2 -Methyl dimethylacetoacetate, 2
-(oxymethyl)ethyl acetoacetate, ethyl 2-oxylevulinic acid, ethyl 4-oxy-3,3-dimethyl-2-oxobutyrate, ethyl 2-(2-oxyethyl)acetoacetate, ethyl 2-oxylevulinic acid, 4-oxy-3
, methyl 3-dimethyl-2-oxobutyrate, ethyl 2-(2-oxyethyl)acetoacetate, methyl xyluronate,
Ethyl 10-oxy-9-oxostearate, as a tetronic acid ester compound, ethyl 3-methyltetronate, methyl 3-acetyl-3-ethoxycarbonyltetronate, methyl 5-methyltetronate, methyl chlorinate, carphosphoric acid Methyl, methyl carphosphate, methyl terrestrate, methyl penicillate, methyl dihydropenicillate, oxyoxodicarboxylic acid ester compounds such as ethyl oxyoxalacetate, diethyl ethoxyoxalacetate, ethyl glycoylmalonate, 4-oxy-4-methyl Examples include ethyl-2-oxoglutarate and diethyl (ethoxyacetyl)malonate.

The reason for this is that the blending ratio of the oxoacid ester compound to the alkali-soluble polymer having a phenol skeleton is preferably 1 to 500 parts by weight, more preferably 5 to 300 parts by weight, based on 100 parts by weight of the polymer. If the amount of the compound is less than 1 part by weight, sufficient photosensitivity cannot be imparted, whereas if the amount exceeds 500 parts by weight, coating properties deteriorate and it is difficult to form a resist film with a uniform thickness. This is because it may be difficult to form.

On the other hand, the acid-generating compound of the present invention is as follows.

Various known compounds and mixtures may be mentioned. For example, diazonium salts, phosphonium salts, sulfonium salts, and iodonium CF, SO3-, P-CI, Ph5OJ-
.

Salts such as P-NO and Ph502-, organic halogen compounds, orthoquinone-diazide sulfonyl chloride, and the like can be used as the acid-generating compound of the present invention. All organic halogen compounds known as free-radical-forming photoinitiators are hydrohalic acid-forming compounds and can be used as acid-generating compounds in the present invention.

Specific examples of compounds that generate this acid in the present invention include di(paratertiary butylbenzene)iodonium trifluoromethanesulfonate, diphenyliodonium trifluoromethanesulfonate, bezoi,
, -t-, O71.2, Zil para-toluene sulfonate, Triphenyl sulfonium triple olomethane sulfonate, Tri(tert-butylphenyl) sulfonium trifluoromethane sulfonate, Benzenediazonium para-toluene sulfonate, Tris-Schiff 1 bromomethyl-S -triazine, 0-naphthoquinonediazide-4-sulfonic acid chloride, etc. can be used.

The content of the acid-generating compound of the present invention is suitably in the range of about 0.01 to about 10% by weight, more preferably 0.1 to about 10% by weight, based on the total weight of the solid content of the photosensitive composition. 5% by weight
is within the range of If it is less than 0.01% by weight, no effect can be obtained by adding it, while if it exceeds 10% by weight, the coating properties will deteriorate. Since it contains such acid-generating compounds, the acid generated by exposure to light decomposes the oxo-acid ester compound and decarboxylates it, resulting in a polymer containing phenol and an oxo-acid ester compound. interaction disappears and a pattern latent image is formed. By developing this, a desired pattern can be obtained.

In addition, the alkali-soluble silicon-containing polymer having a phenol skeleton used in the photosensitive composition (1) of the present invention includes (1) polysiloxane having phenol in the side chain, (2) polysilane having phenol in the side chain, or (2) silicon-containing polymer. Examples include novolac resins synthesized from phenol in the side chain. Specific examples of the polysiloxanes mentioned above are shown in Table 1 below. Specific examples of the polysiloxanes mentioned above are shown in Table 2 below. Examples of the novolac resins (2) include those obtained by condensing silicon-containing phenol monomers and phenols shown in Table 3 below with formalin or aldehydes. Examples of phenols used here include phenol,
O-chlorophenol, m-chlorophenol, p-chlorophenol, m-cresol, p-cresol, xylenol, bisphenol A, 4-chloro-3-cresol, dihydroxybenzene, trihydroxybenzene and the like can be mentioned.

The blending ratio of the oxoacid ester compound to the alkali-soluble silicon-containing polymer having a phenol skeleton is 1 to 200 parts by weight per 100 parts by weight of the silicon-containing polymer.
It is desirable that the amount is 5 to 100 parts by weight, more preferably 5 to 100 parts by weight.The reason for this is that if the amount of the compound is less than 1 part by weight, sufficient photosensitivity cannot be imparted; This is because if the amount exceeds the weight part, the oxygen RIE resistance of the formed pattern may deteriorate.

In the present invention, an alkali may be used as needed. Examples of the alkali-soluble resin include commercially available novolac resins and poly(p-vinylphenol).

Poly(p-isopropenylphenol), poly(m-isopropenylphenol), copolymer of p-hydroxystyrene and methyl methacrylate, copolymer of p-isopropenylphenol and methyl acrylate, p-hydroxy Copolymer of styrene and methyl acrylate, P-
Any resin may be used as long as it has an aromatic ring and a hydroxyl group in its structural unit, such as a copolymer of hydroxystyrene and methacrylic acid.

Next, a method for forming a resist pattern using the photosensitive composition 0) of the present invention will be explained.

First, a resist solution consisting of the photosensitive composition of the present invention dissolved in an organic solvent is applied onto a substrate by a spin coating method or a dipping method, and then dried to form a resist film. As for the substrate used here.

Examples include a silicon wafer, a silicon wafer having steps on its surface on which various insulating films, electrodes, and wiring are formed, a blank mask, and the like. In addition, examples of the organic solvent include ketone solvents such as cyclohexanone, acetone, methyl ethyl ketone, and methyl isobutyl ketone;
Examples include cellosolve solvents such as methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, and butyl cellosolve acetate, and ester solvents such as ethyl acetate, butyl acetate, and isoamyl acetate. These solvents may be used alone or in the form of a mixture.

Next, the resist film is exposed to deep UV light through a mask having a desired pattern using a mercury lamp or the like as an exposure source, and then developed with an alkaline aqueous solution. As a result, the unexposed portions of the resist film are dissolved and removed to form a desired resist pattern. The alkaline aqueous solution used here is, for example, an organic alkaline aqueous solution such as a tetramethylammonium hydroxide aqueous solution.

Alternatively, inorganic alkali aqueous solutions such as potassium hydroxide and sodium hydroxide can be used.

Next, a two-layer resist system using the photosensitive composition (1) of the present invention will be explained.

First, after applying a flattening agent on the substrate,
Baking is performed at a temperature of 30 to 150 minutes to form a planarization layer of desired thickness. Examples of the substrate used here include a silicon wafer, a silicon wafer having steps on its surface on which various insulating films, electrodes, and wiring are formed, a blank mask, and the like. The planarizing agent may be any material as long as it has a purity that does not cause any trouble in the production of semiconductor devices, etc. Examples of such planarizing agents include positive resists made of substituted naphthoquinone diazide and novolak resin, polystyrene, Polymethyl methacrylate, polyvinylphenol.

Examples include novolak resin, polyester, polyvinyl alcohol, polyethylene, polypropylene, polyimide, polybutadiene, polyvinyl acetate, and polyvinyl butyral. These resins may be used alone or in the form of mixtures.

Next, after applying a resist solution consisting of the photosensitive composition (1) of the present invention dissolved in an organic solvent on the flattening layer,
Examples of the solvent for the photosensitive composition of the present invention, which is dried at 150°C or lower, preferably 50 to 120°C to form a resist film of a desired thickness, include 1, for example, cyclohexanone, acetone,
Examples include ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, cellosolve solvents such as methyl cellosolve, methyl cellosolve acetate, and ethyl cellosolve acetate, and ester solvents such as ethyl acetate, butyl acetate, and isoamyl acetate. These solvents are
They may be used alone or in the form of a mixture. As the coating means, for example, a spin coating method using a spinner, a dipping method, a spraying method, a printing method, etc. can be adopted. The thickness of the resist film can be arbitrarily adjusted by adjusting the coating means, the silicon resin concentration in the photosensitive liquid, the viscosity, and the like.

Next, by exposing a desired portion of the resist film on the planarization layer to light, the exposed portion has lower solubility in the alkaline aqueous solution than the unexposed portion. The optimum n light amount during this exposure depends on the types of components constituting the resist film, but is usually preferably in the range of 1a+J/a# to 10J/-. Further, for exposure, either a contact exposure method or a projection exposure method can be adopted. Subsequently, the exposed resist film is developed with an alkaline aqueous solution. As a result, the unexposed portions of the resist film are dissolved and removed to form a desired resist pattern. The alkaline aqueous solution used here may be any one that quickly dissolves the unexposed part of the cyst film and has an extremely low rate of dissolution in other exposed parts.1 For example, a tetramethylammonium hydroxide aqueous solution. Examples include tetraalkylammonium aqueous solutions such as, and inorganic alkali aqueous solutions such as potassium hydroxide and sodium hydroxide. These alkaline aqueous solutions are usually used at a concentration of 15% by weight or less. Further, as the developing means, for example, a dipping method, a spray method, etc. can be adopted. After development, the developer is washed away with water.

Next, using the formed resist pattern as a mask, the exposed planarization layer is etched by oxygen reactive ion etching (oxygen RIE). At this time, the resist pattern made of the photosensitive composition of the present invention is oxygen RI.
Silicon dioxide (
Sun, ) or similar films are formed and have 10 to 100 times the acid 1 RIE resistance of the exposed planarization layer.

Therefore, the planarization layer portion exposed from the resist pattern is selectively removed by the oxygen RIE method, and an optimal pattern profile is obtained.

A wet etching method and a dry etching method are used as the etching method for etching the substrate using the pattern formed by such a process as a mask.When forming a fine pattern of 3p or less, the dry etching method is used. preferable. Wet etching agents include hydrofluoric acid aqueous solution, ammonium fluoride aqueous solution, etc. when etching a silicon oxide film, and phosphoric acid aqueous solution, acetic acid aqueous solution, nitric acid aqueous solution when etching aluminum. When a chromium-based film is to be etched, an aqueous solution of cerium ammonium nitrate or the like is used. As a dry etching gas, CF4. C,FCC4,,BCa,,CQ
, , HCQ, etc., and these gases may be used in combination as necessary.

Etching conditions include the concentration of wet etching agent in the reaction tank, the concentration of dry etching gas, reaction temperature and reaction time, etc., based on the combination of the material on which the fine pattern is to be formed and the photosensitive composition. However, the method is not particularly limited.

After the above-described etching, the pattern made of the planarization layer and resist remaining on the substrate is removed using a stripping agent such as Nagase Kasei Co., Ltd. trade name: J-100.

Remove using oxygen gas plasma, etc.

In addition to the above steps, it is acceptable to add further steps depending on the purpose. For example, the purpose is to improve the adhesion between the resist film made of a photosensitive composition and the flattening layer, or between the flattening layer and the substrate. Examples include a pretreatment step performed before application of each liquid, a beta step performed before or after development, and a reirradiation step with ultraviolet rays performed before dry etching.

As described above, the omega photosensitive composition of the present invention is well sensitive to deep UV because it is composed of an alkali-soluble polymer having a phenol skeleton, an oxoacid ester compound, and an acid-generating compound. , can be used as a positive type resist. Further, by performing exposure and development using the photosensitive composition, a fine pattern having a rectangular cross section that has excellent dry etching resistance and high tolerance during the process can be formed.

In addition, the photosensitive composition (1) of the present invention is good against deep UV because it is composed of an alkali-soluble silicon-containing polymer having a phenol skeleton, an oxoacid ester compound, and a compound that generates an acid when exposed to light. It is sensitive to light, has excellent resistance to oxygen reactive etching (oxygen RIE resistance), and can be developed with an alkaline aqueous solution, so it can be applied to a two-layer resist method and can form fine patterns.

(Example with Zero Capacity Spot) Examples related to the omega photosensitive composition of the present invention will be described in detail below.

Example 1 75 g of poly(p-vinylphenol), 25 g of dimethyl 7cetone dihydroborate, and 0.5 g of diphenyliodonium trifluoromethanesulfonate were dissolved in 250 g of ethyl cellosolve acetate to form a 0.2-fluororesin membrane. A resist solution was prepared by filtration using a filter.

Next, the resist solution was applied onto a silicon wafer and dried on a hot plate at 90°C for 5 minutes to a thickness of 1.
．． An OIIM resist film was formed. Subsequently, this resist film was exposed to light (100 mJ/aJ) using a reduction projection exposure machine using KrF (248n) # excimer laser light. Thereafter, the film was developed by immersing it in a 1.2% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. As a result, a highly accurate positive resist pattern having a rectangular shape with a width of 0.3 μm was formed.

Example 2 A resist solution was prepared by using 1.0 g of benzoin tosylate in place of the iodonium salt in Example 1.

When exposed and developed in the same manner as in Example 1, 0.
A highly accurate positive resist pattern having a 3- rectangular shape was obtained.

Example 3 75 g of m,p-cresol novolak resin, 25 g of diethyl oxalyl acetate, and 2 0-nitrobenzyl tosylate
A resist solution was prepared in the same manner as in Example 1 using G.

When exposed and developed in the same manner as in Example 1,
A highly accurate resist pattern having a rectangular shape of 0.3% was obtained.

Example 4 In Example 1, 1.0 g of tri(tert-butylphenyl)sulfonium trialolomethanesulfonate was used instead of the iodonium salt.

A resist solution was prepared.

When exposed and developed in the same manner as in Example 1, 0.
3. A highly accurate positive resist pattern having a rectangular shape was obtained.

Example 5 The same procedure as in Example 1 was carried out using 75 g of novolak resin synthesized from 3.5-xylenol and m-cresol (1;1), 25 g of 2-oxoglutaric acid, and 4.0 g of diphenyliodonium trifluoromethanesulfonate. A resist solution was prepared.

When exposed and developed in the same manner as in Example 1, 0.
A highly accurate resist pattern having a 3- rectangular shape was obtained.

Example 6 Using 75 g of poly(p-vinylphenol), 25 g of ethyl acetopyruvate, and 5 g of benzointosylate,
A resist solution was prepared in the same manner as in Example 1.

When exposed and developed in the same manner as in Example 1, 0.
A highly accurate resist pattern having a 3- rectangular shape was obtained.

Example 7 A resist solution similar to that in Example 1 was applied to an aluminum film formed on a silicon wafer, and exposed and developed in the same manner as in Example 1 to form a resist pattern with a width of 0.3p. . Next, using this resist pattern as a mask, the exposed aluminum film was dry etched using CBrCQ gas. The width of the resist pattern could be faithfully transferred to the aluminum film.

Comparative Example 1 A polymethyl methacrylate solution was applied to an aluminum film formed on a silicon wafer, exposed and developed in the same manner as in Example 1 to form a resist pattern, and then exposed using the resist pattern as a mask. CBrCI2. When dry etching was performed using gas, the polymethacrylate pattern disappeared during the etching of the aluminum, making it impossible to transfer the pattern.

Examples relating to the photosensitive composition (1) of the present invention will be described in detail below.

Example 8 75 g of polysiloxane represented by the following structural formula (A)
and 7cetone dimethyl dicarboxylate 25 g and diphenyliodonium trifluoromethanesulfonate 0.5 g
was dissolved in 300 g of ethyl cellosolve acetate and filtered using a 0.2-fluororesin membrane filter to prepare a silicon-containing resist solution.

Next, a resist made of commercially available novolac resin was applied to a thickness of 2.0°C on the silicon wafer, and then heated at 200°C.
A flattening layer was formed by heating for 30 minutes.

Next, apply 0.6% of the resist solution on this planarization layer.
It was coated to a thickness of 7 m, prebaked at 90°C for 5 minutes, and exposed using a 248nm KrF excimer laser beam (
100 mJ/ci). Thereafter, it was immersed in a 1.0% by weight aqueous tetramethylammonium hydroxide solution for 1 minute and developed to form a resist pattern. Thereafter, the planarization layer was etched by oxygen RIE using the resist pattern as a mask.

When a cross-section of the pattern of the planarization layer after etching by oxygen RIE method was observed with a scanning electron microscope, it was found that the film thickness was 2.3 mm, and the line width and line spacing were both 0.3 mm. It was confirmed that it has a rapid profile.

Example 9 75 g of polysiloxane represented by the following structural formula (B)
A silicon-containing resist solution was prepared by dissolving 25 g of dimethyl α-ketoglutarate and 1.0 g of O-nitrobenzyl tosylate in 400 g of ethyl cellosolve acetate, and filtering the solution using a 0.2-fluorine resin membrane filter. did.

Next, a commercially available resist made of novolac resin was applied to a thickness of 2.0 mm on the silicon wafer, and the resist was heated at 200°C for 3.
After heating for 0 minutes to form a flattening layer, coating, exposure, TIt image, oxygen R
When IE was performed, a pattern was obtained that had a film thickness of 2.3 mm and a line width and line spacing of 0.3 p, each having a sharp profile.

Example 10 A novolak resin 75 synthesized from a phenol having silicon in its side chain represented by the following structural formula (C), 25 g of tert-butyl acetoacetate, and 2 g of benzoin tosylate were mixed with ethyl cellosolve acetate 400. and filtered using a 0.2 gm fluororesin membrane filter to prepare a silicon-containing resist solution.

L■.

Next, a resist made of a commercially available novolac resin was applied to a thickness of 2.0 mm on the silicon wafer.

After heating at 200° C. for 30 minutes to form a flattening layer.

Using the above resist, coating, exposure, and l
! image, and oxygen RIE was performed. However, as a developer, 3
．． An aqueous solution of tetramethylammonium hydroxide with a concentration of 0% by weight was used. As a result, the film thickness was 2.3- and the line width and line spacing were both 0.3. A pattern with a sharp profile was obtained.

Example 11 In place of the iodonium salt in Example 8, 1.0 g of tri(tert-butylphenyl)sulfonium trifluoromethanesulfonate was used.

A resist solution was prepared.

As a result of performing exposure, development, and RIE in the same manner as in Example 8,
A resist pattern with a sharp profile of 0.37 m was obtained.

Example 12 In Example 8, 25 g of diethyl 2-acetylglutarate was used instead of dimethyl acetonedicarboxylate,
A resist solution was prepared.

As a result of performing exposure, development, and RIE in the same manner as in Example 8,
A resist pattern with a sharp profile of 0.3- was obtained.

Example 13 In Example 8, 25 g of triethyl oxalmalonate was used instead of acetone and dimethyl dicarboxylate,
A resist solution was prepared.

As a result of performing exposure, development, and RIE in the same manner as in Example 8,
A resist pattern with a sharp profile of 0.3 μI was obtained.

〔Effect of the invention〕

As described in detail above, the photosensitive composition (1) of the present invention is well sensitive to deep UV, has excellent dry etching resistance, and can form fine patterns with high tolerance upon exposure and development.

Furthermore, it has remarkable effects such as being able to be effectively used as a mask in the dry etching process of semiconductor devices.

Further, according to the photosensitive composition (1) of the present invention, deep UV
It is well exposed to light, has excellent oxygen RIE resistance, can be developed with an alkaline aqueous solution, can be applied to a two-layer resist system, and is extremely convenient for microfabrication. It has a great effect.

(Margin below) Table 1 (continued) Table 1 (continued) No. table Table 3 (continued) No. table et Hl ■ Table 3 (continued) Table 3 (continued) Table 3 (continued) υH et ■.

Table 3 (continued) 2H5 zHs Table 3 (continued) zHs Faith

Claims (2)

[Claims] (1) A photosensitive composition comprising: an alkali-soluble polymer having a phenol skeleton; an oxoacid ester compound; and a compound that generates an acid when exposed to light. (2) A photosensitive composition, wherein the alkali-soluble polymer according to claim (1) is a silicon-containing polymer.