WO2007111271A1

WO2007111271A1 - Composition for forming silica coating and silica coating

Info

Publication number: WO2007111271A1
Application number: PCT/JP2007/056091
Authority: WO
Inventors: Kiyoshi Ishikawa; Toshiyuki Ogata; Hideo Hada; Shogo Matsumaru
Original assignee: Tokyo Ohka Kogyo Co., Ltd.
Priority date: 2006-03-24
Filing date: 2007-03-23
Publication date: 2007-10-04
Also published as: TW200740939A; JP2007254677A; TWI358431B

Abstract

Disclosed is a composition for forming a silica coating which enables to form a silica coating by being applied over a substrate and then heated thereon at a low temperature. Also disclosed is a silica coating obtained by using such a composition. Specifically disclosed is a composition for forming a silica coating, which contains a hydrolysis-condensation product (A) of an alkoxysilane and a compound (B) which generates an acid or a base by the action of heat. It is preferable that the compound (B) generates an acid or a base at a temperature of not less than 100˚C but not more than 300˚C.

Description

Composition for forming silica-based film and silica-based film

Technical field

[0001] The present invention relates to a composition for forming a silica-based film and a silica-based film. More specifically, the present invention relates to a composition for forming a silica-based film capable of forming a film at a low temperature and a silica-based film.

Background art

[0002] A composition for forming a silica-based film is mainly used for reducing a step in a semiconductor wiring or filling a groove between wirings to form a silica-based film. Since the liquid is applied, the pattern recess on the wafer can be easily embedded, and the wiring can be flattened with good reproducibility. This silica-based film is particularly preferably used as an interlayer insulating film.

Such a silica-based coating is generally obtained by applying a composition for forming a silica-based coating on a substrate, heating at 80 ° C. to 300 ° C., and baking at a temperature of 350 ° C. or higher. (For example, refer to Patent Document 1).

Patent Document 1: Japanese Patent Laid-Open No. 2005-171067

Disclosure of the invention

Problems to be solved by the invention

[0004] As described above, a firing process at a high temperature of 350 ° C or higher is required, leading to a decrease in productivity. In addition, firing at a high temperature is preferable for exhibiting the desired characteristics of the silica-based coating because the organic group bonded to the silicon decomposes, etc.

[0005] The present invention has been made in view of the above-described problems, and provides a composition for forming a silica-based film that can form a silica-based film by heating at a low temperature. With the goal.

Means for solving the problem

[0006] In order to solve the above-mentioned problems, the present inventors have made extensive studies focusing on the additive agent added to the silica-based film forming composition. As a result, it generates acid or base by the action of heat. It has been found that the above problems can be solved by using a compound, and the present invention has been completed. More specifically, the present invention provides the following.

[0007] A first invention of the present invention is a composition for forming a silica-based film comprising a siloxane polymer (A) and a compound (B) that generates an acid or a base by the action of heat.

[0008] The second invention of the present invention is a silica-based coating obtained from the above-mentioned composition for forming a silica-based coating.

The invention's effect

[0009] The composition for forming a silica-based film of the present invention contains a compound that generates an acid or a base by the action of heat. Thereby, a silica-based film can be easily formed at a temperature of less than 350 ° C.

Brief Description of Drawings

FIG. 1 is a diagram showing a FT-IR chart of Example 1.

FIG. 2 is a diagram showing an FT-IR chart of Comparative Example 1.

FIG. 3 is a diagram showing an FT-IR chart of Example 2.

FIG. 4 is a diagram showing an FT-IR chart of Comparative Example 3.

FIG. 5 is a graph comparing the BHF resistance of silica-based coatings in Example 2 and Comparative Example 3.

BEST MODE FOR CARRYING OUT THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described.

[0012] <Silica-based film-forming composition>

The composition for forming a silica-based film of the present invention comprises a siloxane polymer (A) and a compound (B) that generates an acid or a base by the action of heat.

[0013] <Siloxane polymer (A)>

The siloxane polymer of the present invention (hereinafter also referred to as “component (A)”) is not particularly limited, and is a polymer having a Si 2 O 3 Si bond.

Among these siloxane polymers, hydrolysis-condensation products of alkoxysilanes can be suitably used. Any kind of alkoxysilane can be used as the alkoxysilane. Examples of such alkoxysilane include, for example, the following general formula (a): Mention may be made of the compounds represented.

[0014] [Chemical 1]

R ¹ _n -S i (OR ² ) ₄ — _n · · · (a)

(In the formula, R ¹ is hydrogen, an alkyl group having 1 to 20 carbon atoms or an aryl group, R ² is a monovalent organic group, and n is an integer of 0 to 2.)

Here, examples of the monovalent organic group include an alkyl group, aryl group, aryl group, and glycidyl group. In these, an alkyl group and an aryl group are preferable. The number of carbon atoms of the alkyl group is preferably 1 to 5, and examples thereof include a methyl group, an ethyl group, a propyl group, and a butyl group. The alkyl group may be linear or branched, and hydrogen may be substituted with fluorine. As the aryl group, those having 6 to 20 carbon atoms are preferred, and examples thereof include a phenyl group and a naphthyl group.

[0016] As specific examples of the compound represented by the general formula (a),

(al) When n = 0, examples include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane,

(a2) When n = l, monomethyltrimethoxysilane, monomethyltriethoxysilane, monomethyltripropoxysilane, monoethyltrimethoxysilane, monoethyltriethoxysilane, monoethyltripropoxysilane, monopropyltrimethoxy Examples include monoalkyltrialkoxysilanes such as silane and monopropyltriethoxysilane, monophenyltrialkoxysilanes such as monophenyltrimethoxysilane, and monophenyltriethoxysilane.

(a3) When n = 2, dialkyl dialkoxysilane, diphenyl such as dimethylenoresimethoxysilane, dimethylenoresetoxysilane, dimethylenoresipropoxysilane, getinoresioxymethoxysilane, methinoresoxyoxysilane, methinoresidipropoxysilane, etc. Examples include diphenyl dialkoxysilanes such as dimethoxysilane and diphenyljetoxysilane.

In the composition for forming a silica-based film of the present invention, the weight average of the siloxane polymer (A) The average molecular weight is preferably 200 or more and 50000 or less, more preferably 1000 or more and 3000 or less. If it is this range, the applicability | paintability of the composition for silica-type film formation can be improved.

[0018] Hydrolytic condensation of alkoxysilane is obtained by reacting alkoxysilane as a polymerization monomer in an organic solvent in the presence of an acid catalyst or a base catalyst. The alkoxysilane used as the polymerization monomer may be used alone or may be condensed by combining plural kinds.

[0019] Further, trialkylalkoxysilanes such as trimethylmethoxysilane, trimethylethoxysilane, trimethylpropoxysilane, triethylmethoxysilane, triethyloxysilane, triethylpropoxysilane, tripylpyroxysilane, tripropylethoxysilane, Triphenylalkoxysilane such as triphenylmethoxysilane and triphenylethoxysilane may be added during hydrolysis.

[0020] The degree of hydrolysis of alkoxysilane, which is a precondition for condensation, can be adjusted by the amount of water to be added. In general, it is preferable that the amount of water added is 1.0 to L: 0.0 times the total number of moles of alkoxysilane represented by the chemical formula (a). More preferably, it is added at a molar ratio of 5 to 8.0. By making the addition amount of water 1.0 mol or more, the degree of hydrolysis can be sufficiently increased, and the film formation can be improved. On the other hand, gelling can be prevented and the storage stability can be improved by controlling the molarity to 10.0 mol or less.

[0021] In addition, in the condensation of the alkoxysilane represented by the chemical formula (a), it is preferable to use an acid catalyst. The acid catalyst that is preferably used is not particularly limited and is conventionally used. Any organic acid or inorganic acid can be used. Examples of the organic acid include organic carboxylic acids such as acetic acid, propionic acid, and butyric acid, and examples of the inorganic acid include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, and the like. The acid catalyst may be added directly to the mixture of alkoxysilane and water, or may be added to the alkoxysilane as an acidic aqueous solution together with water.

[0022] The hydrolysis reaction is usually completed in about 5 to about L00 hours. In addition, it is possible to contain one or more alkoxysilanes represented by the chemical formula (a) at a heating temperature not exceeding room temperature to 80 ° C. It is also possible to complete the reaction in a short reaction time by dropping the acid catalyst aqueous solution into the organic solvent for reaction. The hydrolyzed alkoxysilane then undergoes a condensation reaction, resulting in the formation of a Si—O Si network.

[0023] <Compound capable of generating acid or base by the action of heat (B)>

As a compound that generates an acid or base by the action of heat (hereinafter also referred to as “component (B)”)

As long as it generates an acid or a base by heating, it can be used without any particular limitation. In addition, the compound that generates an acid or a base is preferably a compound that generates an acid or a base at 100 ° C. or higher and 300 ° C. or lower.

[0024] By including the component (B), the composition for forming a silica-based film can form a silica-based film without firing at a high temperature of, for example, 350 ° C or higher. Thereby, heating (for example, drying and baking) after applying the composition for forming a silica-based film can be simplified.

[0025] Further, by including the component (B), chemical resistance against hydrofluoric acid and the like can be improved.

[0026] Examples of such substances include thermal acid generators and thermal base generators. The thermal acid generator is not particularly limited, but 2, 4, 4, 6-tetrabromocyclohexagenone, benzoin tosylate, 2--trobendiltosylate, and other alkyls of organic sulfonic acid. Esters can be used. Specific examples include sulphonium salts, iodine salts, benzothiazonium salts, ammonium salts, phosphonium salts, and the like. Of these, particularly preferred are ododonium salts, sulfo-salts and benzothiazo-salts. Specific examples of the sulfo-um salt and the benzothiazo-um salt include, for example, 4-acetoxyphenol dimethylsulfo-hexafluoroarsenate, benzyl 4-hydroxyphenol methylsulfo-hexafluoro Antimonate, 4-acetoxyphenol pendylmethylsulfo-hexafluoroantimonate, dibenzyl 4-hydroxyphenolsulfo-hexafluoroantimonate, 4-acetoxyphenol pendylsulfo-hexaflux Examples include oloantimonate and 3-benzylbenzothiazolium hexafluoroantimonate.

[0027] The thermal base generator is not particularly limited, but 1-methyl 1- (4 —Biphenyl-ethyl) ethyl carbamate, forceful rubamate derivatives such as 1,1-dimethyl-2-cyanoethylcarbamate, urea derivatives such as urea and N, N-dimethyl-N'methylurea, 1,4-dihydronicotine Dihydropyridine derivatives such as amides, quaternized ammonium salts of organic silanes and organic boranes, dicyandiamide and the like are used. In addition, trichlorodiethyl acetate guanidine, trichlorodimethylacetate acetate, potassium trichlorodiacetate, phenylsulfonylacetate guanidine, p-diphenylsulfolacetate guanidine, p-methanesulfursulfate -Lusulfol acetate guanidine, phenol-potassium propylpropiolate, guanidine propylpropiolate, cesium ferropropiolate, p-chlorophenol guanidine propylpropiolate, p-phthalene bisphenol Examples include guanidine lupropiolic acid, tetramethylammonium phenolsulfol acetate, and tetramethylammonium phenolpropiolate.

Among these, it is particularly preferable to use a compound represented by the following chemical formula (b-1) and the following chemical formula (b-2).

[0029] [Chemical 2]

[0030] [Chemical 3]

[0031] Further, these compounds generating an acid or a base may be used alone or in combination of two or more.

[0032] The content of the component (B) is 0.1% by mass or more and 20 quality with respect to the SiO equivalent mass of the component (A).

2

More preferably, the amount is 0.5% by mass or more and 15% by mass or less. By setting the component (B) within the above range, the temporal stability of the composition for forming a silica-based film can be improved.

[0033] <Other ingredients>

(Surfactant)

It is preferable to mix | blend surfactant with the composition for silica-type film formation of this invention. Due to the presence of the surfactant, it is possible to improve the coatability and spreadability on the substrate.

[0034] (Solvent)

The composition for forming a silica-based film of the present invention preferably contains a solvent for the purpose of improving coating properties and film thickness uniformity. As this solvent, an organic solvent generally used conventionally can be used. Specific examples include monohydric alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, 3-methoxy-3-methyl-1-butanol, 3-methoxy-1-butanol; methyl 3-methoxypropionate, ethyl 3-ethoxy Alkyl carboxylic acid esters such as propionate; polyhydric alcohols such as ethylene glycol, diethylene glycol, and propylene glycol; ethylene glycol monomethino enoenoate, ethylene glycol monometheno enoenoate, Tylene glycol monopropinoreateol, ethylene glycol monobutinoleatenore, propylene glyconole monomethinoatenore, propylene glycolenomonotenoleatenore, propylene glycolenomonopropenoatenore, propylene glycol Polyhydric alcohol derivatives such as Noremonobutinoreethenole, Ethylene Glycoleomonomethenoleetenore Acetate, Ethylene Glycoleo Monoethylenoleate Monoteracetate, Propylene Glycol Monomethyl Ether Acetate, Propylene Glycol Monoethyl Ether Acetate; Examples include fatty acids such as acetic acid and propionic acid; ketones such as acetone, methyl ethyl ketone, and 2-heptanone. Of these, alcohol solvents and glycol solvents are preferably used. These organic solvents may be used alone or in combination of two or more.

[0035] The amount of the solvent is not particularly limited, but it is preferable that the concentration of components (solid content) other than the solvent is 5 to: LOO mass% 20 to 50 mass % Is more preferable. By making it in this range, the coatability can be improved.

[0036] (Other)

Further, in the present invention, other resin, additives, and the like can be blended within a range that does not impair the effects of the present invention.

[0037] << Method for Forming Silica Film >>

As a method for forming a silica-based coating, first, a composition for forming a silica-based coating is applied on a substrate. As a method for applying the composition for forming a silica-based film on the substrate, for example, any method such as a spray method, a spin coat method, a dip coat method, a roll coat method can be used. Is used.

[0038] Next, the silica-based film-forming composition applied on the substrate is heat-treated. The heat treatment is not particularly limited with respect to its means, temperature, time, etc. In general, it may be performed on a hot plate at about 80 to 300 ° C. for about 1 to 6 minutes.

[0039] According to the composition for forming a silica-based film of the present invention, an acid or a base is generated by heating with a heat treatment. Hydrolysis is promoted by the generated acid or base, so that the alkoxy group becomes a hydroxyl group and alcohol is generated. After that, the two molecules of alcohol condense and a Si-O-Si network is formed. A dense silica-based film can be obtained.

[0040] In addition, the heat treatment is preferably performed in three steps or more and in steps. Specifically, after the first heat treatment for about 30 seconds to 2 minutes on a hot plate at about 60 to 150 ° C in the atmosphere or an inert gas atmosphere such as nitrogen, 100 to 220 ° The second heat treatment is performed for about 30 seconds to 2 minutes at about C, and the third heat treatment is performed for about 30 seconds to 2 minutes at about 150 to 300 ° C. Thus, by performing stepwise heat treatment of three or more steps, preferably about 3 to 6 steps, a silica-based film can be formed at a lower temperature.

Example

Next, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

[Example 1]

Spin-on glass material based on trialkoxysilane hydrolysis product (OCD T-12 1000V (trade name): Tokyo Ohka Kogyo Co., Ltd., SiO equivalent solid content: 7 mass

2

%)), The above-mentioned compound (b-1) was added so as to be 7.5% by mass with respect to the solid content in the spin-on glass material to produce a composition for forming a silica-based film. A composition for forming a silica-based film was applied on a 6-inch silicon wafer using a coater (SS8261NUU: manufactured by Tokyo Ohka Kogyo Co., Ltd.) at a rotation speed of lOOOOrpm. Next, heating was performed on a hot plate at 80 ° C. for 60 seconds, 150 ° C. for 60 seconds, and 200 ° C. for 60 seconds to form a silica-based film.

Spin-on glass material containing hydrolysis product of tetramethoxysilane Z monomethyltrimethoxysilane = 1/1 (molar ratio) (OCD T-7 7000WK80A (trade name): manufactured by Tokyo Ohka Kogyo Co., Ltd., SiO converted solid The concentration of the compound (b-1) is

2

A silica-based film forming composition was produced by adding 7% by mass with respect to the solid content in the non-on glass material. The composition for forming a silica-based film was applied onto a 6-inch silicon wafer at a rotational speed of lOOOOrpm using a coater (SS8261NUU: manufactured by Tokyo Ohka Kogyo Co., Ltd.). Next, heat on a hot plate at 300 ° C for 60 seconds to form a silica coating. Made.

[0044] <Comparative Example 1>

A silica-based film was produced in the same manner as in Example 1 using OCD T-12 1000V.

[0045] <Comparative Example 2>

In Comparative Example 1, after heating, firing was further performed at 400 ° C. in a nitrogen atmosphere to form a silica-based film.

[Comparative Example 3]

A silica-based film was formed in the same manner as in Example 2 using OCD T-7 7000WK80A.

[0047] <Comparative Example 4>>

In Comparative Example 3, after heating, firing was further performed at 400 ° C. in a nitrogen atmosphere to form a silica-based film.

[0048] <Filmability evaluation>

The film-formability evaluation was performed using Ding-1! ^ Ding 11 ^ -615 (trade name) manufactured by JASCO Corporation. Example 1 and Comparative Examples 1 and 2 were evaluated based on the ratio of the peak area of Si—O bond to the peak area of Si—H bond. Further, Example 2 and Comparative Examples 3 and 4 were evaluated based on the ratio of the peak area of the Si—O bond and the peak area of the Si—C bond. Incidentally, FT-shows in the IR Ji Yato, peak Si- O bond 1050 cm ^_1 around, 2250 cm peak near ^_1 Si- H bond, the peak of 1275 cm ^{_ 1} near the Si- C bond. The results are shown in Tables 1 and 2. Also, the FT-IR chart of Example 1 is shown in FIG. 1, the FT-IR chart of Comparative Example 1 is shown in FIG. 2, the FT-IR chart of Example 2 is shown in FIG. 3, and the FT-IR chart of Comparative Example 3 is shown. Figure 4 shows the IR chart.

[0049] [Table 1]

Si-O / Si -H

Row 1 4591 3.756

Ghost 1 4325 2. 364

Row 2 4221 3.164 [0050] [Table 2]

[0051] From Tables 1 and 2, Examples 1 and 2 in which the additive was added compared to Comparative Example 1 and Comparative Example 3 in which the additive (Compound (b-1)) was used It was confirmed that a Si-O-Si network was formed by heating below 200 ° C. In addition, compared to Comparative Examples 2 and 4, which were fired at 400 ° C, a Si-O-Si network was formed that was equivalent to or better than when fired at a higher Si-OZSi-H ratio. I was able to confirm.

[0052] Furthermore, the second embodiment, the silica-based film of Comparative Example 3, 3 parts by mass ^_0/0 resistance Noffa for one Dofu' (BHF) acid concentration, time after applying the BHF onto the silica-based film It confirmed by measuring the amount of film | membrane slips with respect to. The results are shown in Fig. 5.

As shown in FIG. 5, it was confirmed that the coating of Example 2 had higher chemical resistance than Comparative Example 3.

Claims

The scope of the claims

A composition for forming a silica-based film, comprising: a siloxane polymer (A); and a compound (B) that generates an acid or a base by the action of heat.

2. The composition for forming a silica-based film according to claim 1, which is a compound capable of generating an acid or a base at a force of 100 ° C. or higher and 300 ° C. or lower.

The composition for forming a silica-based film according to claim 1 or 2, wherein the compound (B) generating the acid or base is a compound represented by the following structural formula (b-1) or (b-2).

[Chemical 1]

[4] The content of the compound (B) that generates the acid or base is the SiO equivalent mass of the component (A).

2. The composition for forming a silica-based film according to claim 1, wherein the composition is 0.1% by mass or more and 20% by mass or less.

[5] The composition for forming a silica-based film according to any one of [1] to [4], wherein the siloxane polymer (A) is a hydrolysis-condensation product of alkoxysilane. 6. The composition for forming a silica-based film according to claim 5, wherein the alkoxysilane contains at least one selected from compounds represented by the following general formula (a).

[Chemical 3]

R ¹ _n — S i (OR ² ) ₄ — _η · · · (a)

[7] A silica-based film obtained from the composition for forming a silica-based film according to any one of claims 1 to 6.