JP2621760B2 - Composition for coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition containing a siloxane polymer, and is particularly suitable as a buffer coat for semiconductor devices, a flattening agent, or a protective film for a liquid crystal display. The present invention relates to a coating composition used in the above.

[0002]

2. Description of the Related Art Conventionally, various coating compositions containing a siloxane polymer obtained by hydrolyzing and condensing a silane having a hydrolyzable group have been proposed. However, the conventional coating composition has low crack resistance, and its film thickness is limited to 2 μm, so that it is used as a buffer coat for a semiconductor device, a flattening agent, or a protective film of a liquid crystal display. Was inadequate.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a coating composition having excellent crack resistance and suitably used even when a thick film is required.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to provide a compound represented by the general formula (2) RSi ( 1 mole) per mole of a bifunctional silane represented by the general formula (1) R ₂ Si (OR ′) _2. oR ') ₃ in the trifunctional silane to 20 moles containing silane mixture hydrolysis and siloxane polymer obtained by condensation represented, film hardener, and a solvent
The solvent is by-produced by hydrolysis of the alkoxysilane.
And a coating composition characterized by being substantially free of alcohol .

(Where R represents hydrogen, an alkyl group, an aryl group, an alkenyl group, or a substituted product thereof;
Each may be the same or different. R 'is Mechi
And ethyl groups, each of which is the same or different
May be. ) That is, the present invention is a result of the present inventors have conducted extensive studies, the use of difunctional silanes began heading by considerations such that film stress measuring play a significant effect in improving the crack resistance It is based on that. Further, the content of the tetrafunctional silane greatly affects the crack resistance. Further, the content of silane in which R is a phenyl group also has a great effect on improving crack resistance. Therefore, by setting these contents to a specific range and containing a film curing agent, it becomes possible to form a film,
In addition, the crack resistance becomes sufficiently excellent.

Hereinafter, the configuration of the present invention will be described in order.

The siloxane polymer used in the present invention is represented by the following general formula (2): RSi (OR ') ₃ per mole of a bifunctional silane represented by the general formula (1) R ₂ Si (OR') ₂ Is obtained by hydrolyzing and condensing a silane mixture containing 1 to 20 mol of a trifunctional silane represented by the following formula:

(Where R is hydrogen, an alkyl group, aryl
Represents an alkyl group, an alkenyl group, and a substituted product thereof,
Each may be the same or different.R 'is Mechi
And ethyl groups, each of which is the same or different
May be. )The silane compound is represented by the general formula (1)
The general formula (3) Si per mole of the bifunctional silane(OR ') _Four  Even if it contains 5 mol or less of the tetrafunctional silane represented by
good.

Specific examples of R are preferably those having 1 to 6 carbon atoms; hydrogen; alkyl groups such as methyl, ethyl and propyl groups; aryl groups such as phenyl, tolyl and naphthyl groups; vinyl groups. Alkyl groups and aryl groups such as alkenyl groups such as phenyl, allyl groups, and fluoro-substituted forms such as trifluoromethyl groups; epoxy-substituted forms such as 3-glycidoxypropyl groups; and amine-substituted forms such as 3-aminopropyl groups. And alkenyl groups, but are not limited thereto, and they may be the same or different.

R 'is a methyl group or an ethyl group
Each may be the same or different.

The following are specific examples of these silane compounds.

Examples of the bifunctional silane include dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, methylphenyldimethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, and 3-glycidoxypropyl. Methyldimethoxysilane, 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl)
-3-aminopropylmethyldimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropylmethyldiethoxysilane, cyclohexylmethyldimethoxysilane, heptadecafluorodecylmethyldimethoxysilane, 3-methacryloxypropyldimethoxysilane, octadecylmethyldimethoxy silane,, etc., and the like.

Examples of the trifunctional silane include methyltrimethoxysilane, methyltriethoxysilane, hexyltrimethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, Phenyltriethoxysilane, trifluoromethylmethoxysilane, trifluoromethylethoxysilane, 3-aminopropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, N- (2-aminoethyl ) -3-Aminopropyltrimethoxysilane,
3-chloropropyltrimethoxysilane, 3- (N, N
-Diglycidyl) aminopropyltrimethoxysilane,
3-glycidoxypropyl Kishishi trimethoxysilane, heptadecafluorodecyltrimethoxysilane, tridecafluorooctyltrimethoxysilane, trifluoropropyl trimethoxysilane,, etc. may be mentioned.

[0014] 4 functional silane, tetramethoxysilane, tetraethoxysilane,, etc. may be mentioned.

In the present invention, it is important to use a silane mixture containing 1 to 20 mol of trifunctional silane per 1 mol of bifunctional silane in order to obtain a film having excellent crack resistance. is there.

When only the bifunctional silane is used, it is a linear silicone polymer and its thermal decomposition temperature is 300 ° C. or higher. When the amount of the functional silane is 0.3 mol or less, the film is not cured by heating at a normal temperature of 300 to 500C after coating, and a film cannot be formed. When the amount of the trifunctional silane is in the range of 0.3 to 1.0 mol, the film can be formed, but the adhesion to the substrate is not sufficient. Meanwhile, 3
When the amount of the functional silane exceeds 20 mol, crack resistance becomes insufficient. Therefore, for one mole of the bifunctional silane,
Only when the amount of the trifunctional silane is in the range of 1 to 20 mol, crack resistance can be improved without impairing other film properties such as substrate adhesiveness.

In addition, 4 moles per mole of bifunctional silane
The functional silane can be used by mixing at a ratio of 5 mol or less, but the use of a tetrafunctional silane has an advantage of improving the denseness of the film, but leads to a decrease in crack resistance. It is better not to use.

It is preferable that R contains a silane compound having a phenyl group in an amount of 5 to 50 mol%. If the silane compound in which R is a phenyl group is too large, the film becomes cloudy or the transmittance of ultraviolet light decreases. On the other hand, if the amount is too small, the crack resistance decreases.

A siloxane polymer is obtained by adding water to these silane mixtures and subjecting them to hydrolysis and partial condensation.

Specific examples of the silane mixture used include a mixture of 5 mol of methyltriethoxysilane and 1 mol of tetraethoxysilane with respect to 1 mol of diphenyldiethoxysilane, and a mixture of 1 mol of dimethyldimethoxysilane with methyltrimethoxysilane. 2 moles, phenyltrimethoxysilane 1 mole mixture of, etc. can be mentioned.

The reaction may be carried out without a solvent, but is usually carried out in a solvent. The solvent is preferably an organic solvent, methanol,
Ethanol, propanol, butanol, 3-methyl-
Alcohols such as 3-methoxy-1-butanol; glycols such as ethylene glycol and propylene glycol; ethers such as ethylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether and diethyl ether; methyl isobutyl ketone and diisobutyl ketone Ketones; amides such as dimethylformamide and dimethylacetamide; ethyl acetate, ethyl cellosolve acetate, 3-methyl-3-methoxy-1
-Acetates such as butanol acetate; aromatic or aliphatic hydrocarbons such as toluene, xylene, hexane and cyclohexane, γ-butyrolactone,
N-methyl-2-pyrrolidone, dimethyl sulfoxide and the like can be mentioned. The amount of the solvent can be arbitrarily selected, but is preferably used in the range of 0.1 to 3.0 weight per 1 weight of silane.

The water to be added is preferably ion-exchanged water. The amount of water can be arbitrarily selected.
It is preferable to use it in the range of 1.0 to 4.0 mol.

In the reaction, an acid or base catalyst can be used. Hydrochloric acid, sulfuric acid, acetic acid, trifluoroacetic acid, phosphoric acid, polycarboxylic acids or anhydrides thereof, acid catalysts such as ion exchange resins, triethylamine, diethylamine, triethanolamine, diethanolamine,
Base catalysts such as sodium hydroxide, potassium hydroxide, and alkoxysilane having an amino group can be used.

The reaction temperature is usually selected from the range of the freezing point to the boiling point of the reaction system, but it is also possible to carry out the reaction at a temperature higher than the boiling point in a pressurized state. In order to obtain a high-molecular-weight siloxane polymer, the reaction is preferably performed under reflux for 1 to 100 hours. In addition, in order to increase the degree of polymerization of the siloxane polymer, reheating or addition of a base catalyst can be performed.

In the coating composition of the present invention,
Alcohol produced by hydrolysis of alkoxysilane
It is important that they are substantially free of tools. Therefore, anti
From the reaction solution by hydrolysis of alkoxysilane
Cole, that is, methanol or ethanol
Need to be removed. The method of removal is particularly limited
However, preference is given to methyl isobutyl ketone,
Hydrophobic organics such as isobutyl ketone and diethyl ether
Extract siloxane polymer from the reaction solution using a solvent
Wash the organic layer with water or heat it.
For distilling off alcohol and water by-produced by
Is the law.

In order to improve coatability and storage stability,
In addition to removing the produced alcohol, water and red
Alternatively, the catalyst can also be removed.

After removing by-produced alcohol,
Roxane polymer or siloxane polymer solution
If necessary, a solvent can be added. polymer
The concentration is preferably 5 to 80% by weight.
Is preferably 20 to 70% by weight .

The solvent used here is preferably an organic solvent , such as 3-methyl-3-methoxy-1-butanol.
High-boiling alcohols, ethylene glycol, glycols such as propylene glycol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, ethers such as diethyl ether; methyl isobutyl ketone and diisobutyl ketone; dimethylformamide And amides such as dimethylacetamide; ethyl acetate, ethyl cellosolve acetate, and acetates such as 3-methyl-3-methoxy-1-butanol acetate; aromatic and aliphatic hydrocarbons such as toluene, xylene, hexane, and cyclohexane; ,
γ-butyrolactone, N-methyl-2-pyrrolidone, dimethyl sulfoxide and the like can be mentioned.

In the coating solution of the present invention, since a bifunctional silane is used, there is a problem that the film is harder to cure as compared with a case where a trifunctional silane or a tetrafunctional silane is used.
Therefore, a film curing agent is contained as an essential component. Acid and base catalysts are used as the film curing agent, and the acid or base used in the reaction can be left as it is.

It is preferable to use a compound which generates an acid or a base by heat and a compound which generates an acid or a base by light. Specifically, compounds that generate an acid by heat or light include benzoin tosylate, benzoin mesylate, pyrogallol tritosylate, pyrogallol trimesylate, tri (nitrobenzyl) phosphate, trianisofinphosphate, and diaryliodonium salts Examples of compounds that generate a base by heat or light, such as triarylsulfonium salts, include nitrobenzylcyclohexyl carbamate and di (methoxybenzyl) hexamethylenedicarbamate. The amount of these compounds used is
It is preferably from 0.01 to 20% by weight, more preferably from 0.1 to 10% by weight. Further, the coating liquid used in the present invention contains, in addition to a film curing agent, viscosity adjustment as required. Agents, surfactants, stabilizers, coloring agents, vitreous forming agents and the like can be added.

The coating composition of the present invention is applied to a substrate such as a silicon wafer or a ceramic plate by a known method such as spinner or dipping, dried, and the dried film is heated and cured to obtain a composition. It cures completely and becomes a coating film.

The drying temperature is preferably 50 to 150 ° C., the film thickness after drying is preferably 0.5 to 5.0 μm, and the curing temperature is preferably 200 to 450 ° C.

The coating composition of the present invention is used as a buffer coat for a semiconductor device, a flattening agent, a protective film for a liquid crystal display, an interlayer insulating film, a material for forming a waveguide, a material for a phase shifter, and various protective films. But not limited to these.

[0034]

Next, the present invention will be described in more detail with reference to examples.

Example 1 A silane mixture of 1 mol of diphenyldiethoxysilane, 5 mol of methyltriethoxysilane and 1 mol of tetraethoxysilane was dissolved in 100 g of methyl isobutyl ketone, and 10 mol of water and 0.1 mol of phosphoric acid were added thereto. Was added with stirring. The obtained solution was heated and reacted for 3 hours under reflux. Thereafter, the siloxane polymer was extracted using 1 kg of methyl isobutyl ketone, 1 kg of ion-exchanged water was added to the obtained organic layer, and the mixture was shaken. After standing, the aqueous layer was separated and removed. The obtained organic layer was concentrated to dryness to obtain a siloxane polymer.

This siloxane polymer was dissolved in propylene glycol monomethyl ether so as to have a polymer concentration of 50% by weight, and benzoin tosylate was added in an amount of 0.5% by weight based on the polymer to obtain a coating composition. .

This coating composition was applied on a silicon wafer using a spin coater and cured at 300 ° C. for 1 hour. As a result, a good film having a thickness of 8 μm and having no cracks was obtained.

Comparative Example 1 In Example 1, 5 mol of methyltriethoxysilane was used.
A siloxane polymer was synthesized in the same manner as in Example 1 except that a silane mixture of 1 mol of tetraethoxysilane was used as a raw material to obtain a coating composition.

When this coating composition was coated on a silicon wafer using a spin coater, a film thickness of 8
Many cracks occurred at μm.

Comparative Example 2 In Example 2, 2 mol of methyltrimethoxysilane was used.
A siloxane polymer was synthesized in the same manner as in Example 2 except that a mixture of 1 mol of phenyltrimethoxysilane was used as a raw material to obtain a coating composition.

The coating composition was coated on a silicon wafer using a spin coater.
Many cracks occurred at μm.

Example 2 95.2 g of methyltrimethoxysilane (0.7 mol)
l), 36 g of dimethyldimethoxysilane (0.3 mol
1), 39.6 g of phenyltrimethoxysilane (0.2
mol) in propylene glycol monomethyl ether 2
The resultant was dissolved in 00 g, and 60 g of water and 2 g of phosphoric acid were added thereto with stirring. The resulting solution was heated at a bath temperature of 105 ° C. for 2 hours, the internal temperature was raised to 90 ° C., and 90 g of a component mainly composed of methanol as a by-product was distilled off. Next, the mixture was heated at a bath temperature of 130 ° C. for 1.0 hour, the internal temperature was raised to 118 ° C., and 70 g of a component mainly composed of water and propylene glycol monomethyl ether was distilled off, followed by cooling to room temperature to obtain a coating liquid. .

This coating solution was applied to a quartz plate using a spin coater and cured at 250 ° C. for 1 hour. As a result, a colorless and transparent film having a thickness of 5 μm and having no cracks was obtained.

The unit composition of the obtained film was ²⁹ S
When measured by i-solid state NMR, R ₂ SiO, R
The molar ratio of SiO _1.5 was 1: 3, which was consistent with the molar ratio of the raw material 2,3-functional silane.

[0045]

The coating composition of the present invention has excellent crack resistance and can be suitably used as a buffer coat for a semiconductor device requiring a thick film, a flattening agent, or a protective film for a liquid crystal display. it can.

Claims (7)

(57) [Claims] A compound represented by the general formula (1): R ₂ Si (OR
') To the difunctional silane 1 mole represented by _2, the general formula (2) RSi (OR') 3-functional silane to 20 moles containing silane mixture represented by ₃ to hydrolysis and condensation Containing siloxane polymer, film hardener, and solvent
The solvent is by-produced by hydrolysis of the alkoxysilane.
A coating composition comprising substantially no alcohol . (Where R is hydrogen, an alkyl group,
Represents an aryl group, an alkenyl group, and a substituted product thereof, which may be the same or different. R '
Represents a methyl group or an ethyl group.
It may be different. ) 2. The silane mixture is prepared by adding 5 moles of a tetrafunctional silane represented by the general formula (3) Si (OR ′) ₄ to 1 mol of the bifunctional silane represented by the general formula (1). The coating composition according to claim 1, wherein the content is at most mol. 3. 5 to 50 mol% of the silane mixture has R
Is a silane which is a phenyl group. The coating composition according to claim 1 or 2, wherein 4. The coating composition according to claim 1, further comprising a compound capable of generating an acid by heat as a film curing agent. 5. The coating composition according to claim 1, further comprising a compound capable of generating a base by heat as a film curing agent. 6. The coating composition according to claim 1, further comprising a compound capable of generating an acid by light as a film curing agent. 7. The coating composition according to claim 1, further comprising a compound capable of generating a base by light as a film curing agent.