JPH0470663A - Photosensitive resin composition - Google Patents

Abstract

PURPOSE:To obtain a higher glass transition temp. and to improve oxygen plasma resistance by incorporating specific polysiloxane and >=1 kinds of the sensitizers selected from a group consisting of orthonitrobenzyl ester, etc., into the above compsn. CONSTITUTION:The polysiloxane obtd. by the hydrolysis and condensation of alkoxysilane having an oxysilane ring and >=1 kinds of the sensitizers selected from the group consisting of meldrum's acid or its deriv., diazodimedone or its deriv., diazoketone compd., and orthonitrobenzyl ester are incorporated into this compsn. The chemical structure of a ladder type which adopts the siloxane bond as a skeletal structure and uses the multifunctional alkoxysilane as a raw material is adopted in such a manner and the hydroxyl group subjected to ring opening by the introduction of the oxysilane ring, by which alkaline solubility is enabled. The higher glass transition temp. is obtd. in this way and the oxygen plasma resistance is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photosensitive resin composition that reproduces a positive pattern with high precision and has high resistance to oxygen plasma.

[Conventional technology]

Positive-type photoresists made of novolak resin and naphthoquinonediazide as a photosensitizer have recently been used in the field of lithography because they have characteristics such as high sensitivity, high resolution, and alkali solubility. Now, two-layer Gist CB,
J, lJn (B, J.

Lln), Solid State Technology (Sol
id 5tate Technology, Vol. 24, p. 73 (1981):], a pattern with a high shape ratio is anisotropically etched using oxygen plasma etching (0□RIB) using a resist thin film formed on a substrate as a mask. It is obtained by doing. This 02RIB resistance has become extremely important depending on the resist material, and materials that form oxides due to O□RIB, generally materials containing silicon, are
It is said to have excellent resistance. However, current photoresists do not contain silicon components, so
It had the drawback of poor IE resistance. To solve this problem, polysiloxane-based resist materials have been proposed, but this type of material generally has a low glass transition temperature, so it is easy to get dust during processing, it is difficult to control the film thickness, and it is difficult to control the film thickness during development. There were major problems in compatibility with the process, such as deterioration in developability due to deformation.

[Problem to be solved by the invention]

Therefore, the glass transition temperature is high, and 0□RIB
Resist materials with excellent resistance and alkaline development are expected.

An object of the present invention is to provide a photosensitive resin composition that solves the above problems.

[The island's means of solving problems]

To summarize the present invention, the present invention relates to a photosensitive resin composition, which includes a polysiloxane obtained by hydrolysis and condensation of an alkoxysilane having an oxirane ring, Meldrum's acid or a derivative thereof, diazodimedone or a derivative thereof, It is characterized by containing a diazodiketone compound and one or more photosensitizers selected from the group consisting of orthonitrobenzyl esters.

In order to solve the above-mentioned problems, the present invention first improves O,RIB resistance by using siloxane bonds as a skeleton structure, and adopts a ladder-type chemical structure by using polyfunctional alkoxysilane as a raw material. This increases the glass transition temperature, and also increases alkali solubility by introducing an oxirane ring and opening the hydroxyl group.

The polysiloxane constituting the photosensitive resin composition of the present invention is generally synthesized by the following method. first,
A specific alkoxysilane is dissolved in alcohol such as ethanol, and water and a catalyst such as hydrochloric acid are added to this. This catalyst may optionally be omitted. This reaction proceeds at room temperature, but may be heated if necessary. After a predetermined period of time has elapsed, the reaction solution is poured into water, and the precipitated product is filtered out and then dried. The product at this stage may be used for practical purposes, or if a higher polymer is desired, the product may be further reacted with an alkali catalyst in an appropriate solvent. Alternatively, it is also effective to proceed with condensation by further heating in bulk. During this reaction process, the oxirane ring opens and converts into a corresponding hydroxyl group, so that the obtained polysiloxane dissolves in an aqueous alkaline solution.

Furthermore, since the polysiloxane obtained by hydrolysis and condensation of the alkoxysilane of the present invention generally has a silanol group at the end, there is a possibility that this condensation may cause the properties to change over time. To avoid this, the silanol group can be replaced by another non-reactive substituent using a silylating agent.

The alkoxysilane having an oxirane ring used in the present invention is not particularly limited, and is a bifunctional or trifunctional alkoxysilane having an oxirane ring in the molecule. Specifically, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-(N-allyl-
N-glycidyl)aminopropyltrimethoxysilane,
3-(N,N-diglycidyl)aminopropyltrimethoxysilane, N-glycidyl-N,N-bis[3-(
methyldimethoxysilyl)propyl]amine, N-glycidyl-N,N-bis-[3-()rimethoxysilyl)
propyl]amine, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyljethoxysilane, 2(3,4-epoxycyclohexyl)ethyltriethoxysilane, 3-(N-allyl-N-glycidyl) Aminopropyltriethoxysilane, 3-(N,
N-diglycidyl)aminopropyltriethoxysilane, N-glycidyl-N, N-bis[3-methyljethoxysilyl)propyl]amine, N-glycidyl-N
, N-bis-[3-()ethoxysilane)propyl]
Examples include amines and the like.

The present invention also includes polysiloxanes obtained by copolymerizing an alkoxysilane having an oxirane ring with a general-purpose metal alkoxide or metal chloride. Although this type of general-purpose metal alkoxide is not particularly limited, the following are exemplified. Dimethoxydimethylsilane, Jetoxydimethylsilane, Dimethoxymethyl-3,3,3-)lifluoropropylsilane, Jetoxydivinylsilane, Jetoxydiethylsilane, 3
-aminopropyljethoxymethylsilane, 3- (2
-aminoethylamino)propyldimethoxymethylsilane, dimethoxymethylphenylsilane, jetoxymethylphenylsilane, dimethoxydiphenylsilane, jetoxydiphenylsilane, tris(2-methoxyethoxy)vinylsilane, methyltrimethoxysilane, ethyltrimethoxysilane, 3 .3.3-Trifluoropropyltrimethoxysilane, methyltriethoxysilane, 3
-(N-methylamino)propyltrimethoxysilane,
Methyltris-(2-aminoethoxy)silane, triacetoxyvinylsilane, tri(LI)oxyvinylsilane, ethyltriethoxysilane, 3-mercaptopropyltriethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, phenyltrimethoxy Silane, 2-cyanoethyltriethoxysilane, allyltriethoxysilane, propyltriethoxysilane, hexyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, methyltripropoxysilane, phenyltriethoxy Silane, 3-[N-allyl-(2-aminoethyl)
]Aminopropyltrimethoxysilane, 4-trimethoxysilyltetrahydrophthalic anhydride, 4-triethoxysilyltetrahydrophthalic anhydride, 4-triisopropoxysilyltetrahydrophthalic anhydride, 4-trimethoxysilyltetrahydrophthalic acid, 4-triethoxysilyltetrahydrophthalic acid, 4-triisopropoxysilyltetrahydrophthalic acid, tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, tetraethoxyzircone, tetrabutoxyzircon, tetraisopropoxyzircone, tetramethoxygermane, tetraethoxy Titanium, tetrabutoxytitanium, tetrabutoxytin, pentabutoxyniobium, pentabutoxytalium, triethoxyboron, tributoxygallium,
Dibutoxylead, tributoxyneodymium, tributoxyerbium. Among these, phenyltriethoxysilane, methyltriethoxysilane and tetraethoxysilane are particularly preferred from the viewpoint of raw material availability, reactivity, properties of the obtained product, etc. Further, examples of metal chlorides include n-butyltrichlorosilane, dimethyldichlorosilane, ethyltrichlorosilane, methyltrichlorosilane, phenyltrichlorosilane, trichlorovinylsilane, diphenyldichlorosilane, and the like.

The polysiloxane used in the present invention has a thickness of 24 μm.
The light transmittance at 8 nm is 90% or more, and
Even when phenyltriethoxysilane is copolymerized, 7
It is 0% or more, and is promising as a resist for excimer laser.

The catalyst used in the present invention is not particularly limited, and acid catalysts and alkali catalysts are used. Such acid catalysts include hydrochloric acid, hydrofluoric acid, nitric acid, sulfuric acid,
Examples include acetic acid and formic acid. Furthermore, examples of the alkali catalyst include ammonia, sodium hydroxide, potassium hydroxide, calcium hydroxide, and the like.

Resist materials made of polysiloxane can be used in a variety of applications in combination with appropriate photosensitizers.

However, ortho-naphthoquinone-based photosensitizers have large absorption at wavelengths of 300 nm or less, and if they do not fade due to light irradiation, they are not suitable as resist materials for lithography using light sources with wavelengths in the deep ultraviolet region, such as excimer lasers. Therefore, in the present invention, a photosensitive agent that has low light absorption in the deep ultraviolet region or is photobleached is used. For example, diazomeldrum acid and its derivatives, diazodimedone and its derivatives, diazodiketone compounds, orthonitrobenzyl esters, etc. can be mentioned.

Since the above-mentioned polysiloxane is alkali-soluble, it can be used as a positive photosensitive resin composition by adding a photosensitizer. In other words, due to ultraviolet (UV) irradiation, the photosensitizer in the irradiated area becomes the corresponding carboxylic acid or decomposes, so that the dissolution inhibition effect disappears.
Since the irradiated area is removed by alkaline development, it exhibits positive resist characteristics.

In addition, after pattern exposure with high energy ray irradiation,
The image reversal method, in which the entire surface is irradiated with ultraviolet rays and then exposed, can form a negative pattern.

In this photosensitive resin composition, the photosensitizer serves as an inhibitor of resist dissolution in an aqueous alkaline solution. The amount of photosensitive agent added is usually in the range of 5 to 40% by weight; if it is less than 5%, it is difficult to suppress the dissolution of the polymer compound in an alkaline developer, making alkaline development impossible, and if it exceeds 40%. The silicon content as a resist material decreases, and the oxygen plasma resistance decreases. Generally, a preferable addition amount is about 20%.

The photosensitizing agent in the present invention is not particularly limited, but includes the following:
Compounds represented by IV) are preferred.

Next, using the photosensitive resin composition of the present invention, , an example of a method for forming a pattern will be described. First, a film of an organic polymer material is formed on a substrate such as silicon, and the photosensitive resin composition of the present invention is applied thereon to form a two-layer structure. Next, after heat treatment, light is irradiated to make only the irradiated area soluble in a developing solvent, and then the photosensitive resin composition in the irradiated area is removed by development. Next, using the photosensitive resin composition in the non-irradiated area as a mask, the underlying organic polymer film is removed by dry etching using oxygen gas to form a pattern. The above-mentioned organic polymer material may be of any type as long as it can be etched by oxygen plasma, but after pattern formation, when dry etching the substrate using this as a mask, resistance is required, so Group-containing polymers are preferred.

Examples of synthesis of polysiloxane used in the composition of the present invention are shown below, but the invention is not limited thereto.

Synthesis example 1 3-glycidoxypropyltrimethoxysilane 23.6
g (0.1 mol) was dissolved in ethanol, and an aqueous hydrochloric acid solution was added thereto with stirring.

After reacting at room temperature for 24 hours, 14444 was further heated at 60°C.
It took time to react. After cooling to room temperature, add ammonia and further cool for 24 hours.
The reaction continued for hours. After the reaction, the reaction solution was poured into distilled water, and the generated precipitate was filtered off to obtain a white polymer. The product is tetrahydrofuran (THF) ethanol,
It was soluble in solvents such as ethylene glycol monoethyl ether (ethyl cellosolve), methyl isobutyl ketone (MIBK), and acetone. Clear, uniform films were obtained from these solutions.

Synthesis example 2 3-glycidoxypropyltrimethoxysilane 11.8
g (0.05 mol) and phenyltriethoxysilane 1
2. Og (0.05 mol) was dissolved in ethanol and an aqueous hydrochloric acid solution was added thereto with stirring. 24 at room temperature
After reacting for an hour, the reaction was further carried out at 60° C. for 144 hours. After the reaction, the reaction solution was poured into distilled water, and the generated precipitate was filtered off to obtain a white polymer. The product was soluble in solvents such as THF, ethanol, ethyl cellosolve, MIBK, acetone, and ethyl acetate.

Clear, uniform films were obtained from these solutions.

Synthesis example 3 3-glycidoxypropyltrimethoxysilane 11.8
g (0.05 mol) and methyltriethoxysilane8.
9 g (0.05 mol) was dissolved in ethanol, and an aqueous hydrochloric acid solution was added thereto while stirring. After reacting at room temperature for 24 hours, the reaction was further carried out at 60° C. for 144 hours. After the reaction, the reaction solution was poured into distilled water, and the generated precipitate was filtered off to obtain a white polymer. The product was soluble in solvents such as THF, ethanol, ethyl cellosolve, MIBK, acetone, and ethyl acetate. Clear, uniform films were obtained from these solutions.

Synthesis example 4 3-glycidoxypropyltrimethoxysilane 4.72
g (0.02 mol) methyltriethoxysilane 8
．． 9 g (0.05 mol) and tetraethoxysilane 6
．． Dissolve 24 g (0.03 mol) in ethanol,
An aqueous hydrochloric acid solution was added to this while stirring. After reacting at room temperature for 6 hours, ammonia water was added and the mixture was further heated at 60°C.
The reaction was allowed to proceed for 24 hours. After the reaction, the reaction solution was poured into distilled water, and the generated precipitate was filtered off to obtain a white polymer.

The products are THF, ethanol, ethyl cellosolve, MI
It was soluble in solvents such as BK, acetone, and ethyl acetate.

Clear, uniform films were obtained from these solutions.

Synthesis Example 5 24.6 g (0.1 mol) of 2'-(3,4-epoxycyclohexyl)ethyltrimethoxysilane was dissolved in ethanol, and an aqueous hydrochloric acid solution was added thereto while stirring. After reacting at room temperature for 24 hours, further reacting at 60°C for 144 hours.
Allowed time to react.

After the reaction, the reaction solution was poured into distilled water, and the generated precipitate was filtered off to obtain a white polymer. The product was soluble in solvents such as THF, ethanol, ethyl cellosolve, MIBK, and acetone.

Clear, uniform films were obtained from these solutions.

In the infrared spectrum of the product film, the absorption of the methoxy group at 8 and 37 μm observed in the infrared spectrum of the monomer is significantly reduced, and the absorption of the oxirane ring at 11.3 μm is also reduced. . Furthermore, absorption of ○H groups of 2.96 μm, which was not observed in Sentsuma, was observed, confirming the formation of polysiloxane having hydroxyl groups.

Synthesis Example 6 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane 12.3g (0.05 mol) and phenyltriethoxysilane 12. Og (0.05 mol) was dissolved in ethanol and an aqueous hydrochloric acid solution was added thereto with stirring. After reacting at room temperature for 24 hours, an additional 60
The reaction was carried out at ℃ for 144 hours. After the reaction, the reaction solution was poured into distilled water, and the generated precipitate was filtered off to obtain a white polymer. The products are THF, ethanol, ethyl cellosolve,
It was soluble in solvents such as MIBK, acetone, and ethyl acetate. Clear, uniform films were obtained from these solutions.

Synthesis Example 7 12.3 g (0.05 mol) of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and 8.9 g (0.05 mol) of methyltriethoxysilane were dissolved in ethanol and dissolved while stirring. To this was added an aqueous hydrochloric acid solution. After reacting at room temperature for 24 hours, further react at 60℃1
The reaction was allowed to proceed for 44 hours. After the reaction, the reaction solution was poured into distilled water, and the generated precipitate was filtered off to obtain a white polymer.

The products are THF, ethanol, ethyl cellosolve, MI
It was soluble in solvents such as BK, acetone, and ethyl acetate.

Clear, uniform films were obtained from these solutions.

Synthesis Example 8 2-(3,4-epoxycyclohexyl)dityltrimethoxysilane 4.92 g (0.02 mol) methyltriethoxysilane 8.9 g (0.05 mol) and tetraethoxysilane 6.24 g (0.03 mol) was dissolved in ethanol, and an aqueous hydrochloric acid solution was added thereto with stirring. After reacting at room temperature for 6 hours, ammonia water was added and the reaction was further carried out at 60°C for 24 hours. After cooling to room temperature, ammonia was added and the reaction was continued for an additional 12 hours. After the reaction, the reaction solution was poured into distilled water, and the generated precipitate was filtered off to obtain a white polymer. The product is THF.

Ethanol, ethyl cellosolve, MIBK, acetone,
It was soluble in solvents such as ethyl acetate.

Clear, uniform films were obtained from these solutions.

Synthesis example 9 3-glycidoxyprobyltrimethoxysilane 4.72
g (0.02 mol) methyltriethoxysilane 8
．． 9 g (0.05 mol) and 8.52 g (0.03 mol) of tetraisopropo-bovine titanium were dissolved in ethanol, and hydrochloric acid was added thereto with stirring. After reacting under reflux for 12 hours, return to room temperature and add water 144
Reacted for 44 hours. After the reaction, the reaction solution was poured into distilled water,
The generated precipitate was filtered to obtain a white polymer. The products are THF, ethanol, ethyl cellosolve, MIBK,
It was soluble in solvents such as acetone and ethyl acetate. Clear, uniform films were obtained from these solutions.

Synthesis Example 10 4.92 g (0.02 moJL) of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and 19.2 g (0.08 mole) of phenyltriethoxysilane were dissolved in ethanol and stirred. At the same time, an aqueous hydrochloric acid solution was added thereto. After reacting at room temperature for 24 hours, the reaction was further carried out at 60° C. for 14,444 hours. After the reaction, the reaction solution was poured into distilled water, and the generated precipitate was filtered off to obtain a white polymer. The product was soluble in solvents such as THF, ethanol, ethyl cellosolve, MIBK, acetone, and ethyl acetate. Clear, uniform films were obtained from these solutions.

Synthesis Example 11 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane 2.46 g (0.01 mol) 4-trimethoxysilylcitrahydrophthalic anhydride 2.72 g
(0.01 mol) and phenyltriethoxysilane 19
．． 2 g (0.08 mol) was dissolved in ethanol, and an aqueous hydrochloric acid solution was added thereto while stirring. After reacting at room temperature for 24 hours, the reaction was further carried out at 60° C. for 14,444 hours.

After the reaction, the reaction solution was poured into distilled water, and the generated precipitate was filtered off to obtain a white polymer. The product was soluble in solvents such as THF, ethanol, ethyl cellosolve, MIBK, acetone, and ethyl acetate. Clear, uniform films were obtained from these solutions.

Synthesis Example 12 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane 4.92 g (0.02 mol) and methyltriethoxysilane 14.2 g (0.08 mol)
was dissolved in ethanol, and an aqueous hydrochloric acid solution was added thereto while stirring. After reacting at room temperature for 24 hours, an additional 6
The reaction was carried out at 0°C for 14,444 hours. After the reaction, the reaction solution was poured into distilled water, and the generated precipitate was filtered off to obtain a white polymer.

It was soluble in solvents such as raw ff1lltTHF, ethanol, ethyl cellosolve, MIBK, acetone, and ethyl acetate. Clear, uniform films were obtained from these solutions.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.
The invention is not limited to these examples.

Example 1 A solution prepared by dissolving 10 g of the polysiloxane obtained in Synthesis Examples 1 to 12 and 3 g of 0-nitrobenzylcholic acid ester in 50 g of ethyl cellosolve acetate was coated on a silicon wafer to a thickness of about 0.3 μm by a spin coating method. ,80℃
Prebaked for 20 minutes. After pre-beta, far ultraviolet light (excimer laser + 248 nm) was irradiated. After irradiation,
Developed with Microposit 2401 (manufactured by Sibley) and a developer with a water ratio of 1:1, and there was no residual film on the irradiated area.
The sensitivity was calculated as the irradiation amount that resulted in %.

Furthermore, the resolution was determined by measuring the minimum pattern size that can be resolved in a line and space pattern. Table 1 shows the sensitivity and minimum pattern size.

Example 2 Sensitivity and resolution were evaluated in the same manner as in Example 1, using a diazomeldrum acid derivative having the following structure in place of the photosensitizer O-nitrobenzylcholic acid ester in Example 1.

Table 2 shows the sensitivity and resolution. The resolution was evaluated by forming a line & space pattern, and the resolution was 0.3 μm for each material.
A wide pattern was formed.

Photosensitizer■ Photosensitizer■ N+ Photosensitizer■ Example 3 Sensitivity and analysis were carried out in the same manner as in Example 1, using a diazodimedone derivative with the following structure in place of the photosensitizer 0-nitrobenzylcholic acid ester in Example 1. Image quality was evaluated.

■ Table 3 shows the sensitivity. Resolution was evaluated by forming line and space patterns, and patterns with a width of 0.3 μm could be formed with all materials.

Example 4 Sensitivity and resolution were evaluated in the same manner as in Example 1, using a diazodiketone compound having the following structure in place of the photosensitizer 0-nitrobenzylcholic acid ester in Example 1.

■ Table 4 shows the sensitivity. Resolution was evaluated by forming line and space patterns, and patterns with a width of 0.3 μm could be formed with all materials.

Example 5 AZ-1350 resist (manufactured by Hoechst) was coated on a silicon wafer to a thickness of 3 μm, and heated at 200° C. for 30 minutes to insolubilize it. The resist material used in Example 2 was applied on top of this AZ resist by approximately 0.3
It was applied to a thickness of μm and prebaked at 80° C. for 20 minutes. After blivating, far ultraviolet rays were irradiated through a chrome mask with a 0.3 μm line and space pattern, and development was performed with a developer having the same composition as in Example 2, and the mask pattern was transferred to the resist material. After that, A etching was performed using oxygen gas as an etching gas and the resist pattern as a mask using a parallel plate type sputter etching device.
Etched the Z resist. RF power 0.2 W/
By etching for 15 minutes at a gas pressure of 20 mTorr, cm', 0□, the AZ resist in the portions not covered by the resist pattern completely disappeared.

Furthermore, any of the resist materials used in Example 2 was 0.
A 3 μm line and space pattern could be formed with a thickness of about 3 μm.

Example 6 The photosensitive resin composition used in Example 2.3.4 was
It was confirmed that a negative pattern can be formed using the image reversal method using X-rays.

〔Effect of the invention〕

As explained above, the present invention is a photosensitive resin composition consisting of an alkali-soluble polysiloxane and a photosensitizer that has low light absorption in the deep ultraviolet region or is photobleachable, and therefore can be used as a resist material for excimer laser lithography. As a result, it becomes a non-swellable positive resist that can be developed with alkali, allowing the formation of fine patterns with high precision.

Furthermore, the resist containing silicon has high resistance to oxygen plasma, and therefore can be used as an upper layer resist of a two-layer resist. Therefore, there is an advantage that fine patterns of 0.5 μm or less can be formed with a high aspect ratio.

Claims (1)

[Claims] 1. One type selected from the group consisting of a polysiloxane obtained by hydrolysis/condensation of an alkoxysilane having an oxirane ring, Meldrum's acid or its derivatives, diazodimedone or its derivatives, diazodiketone compounds, and orthonitrobenzyl esters. A photosensitive resin composition characterized by containing the above photosensitizer.