JP2000319530A - Composition for semiconductor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thin film of a complex of a silicon-containing metal complex oxide with an aliphatic organic polymer excellent in mechanical strengths, adhesion performance with substrates, crack resistance, uniformity of film thickness and thick film-forming performance. SOLUTION: A thin film of an aliphatic organic polymer-inorganic complex is obtained by applying and gelling a composition comprising an alkoxysilane, at least one metal compound of a metal other than silicon selected from the forth, the fifth, the sixth, the thirteenth and the sixteenth families and an aliphatic organic polymer. Further, a porous silicon-containing metal complex oxide thin film is obtained by removing the aliphatic organic polymer from the thin film. The porous silicon-containing metal complex oxide can be preferably used as an insulating film for multilayer wiring as it is more excellent in mechanical strengths, adhesiveness to substrates, uniformity of film thickness and thick film-forming performance than usual ones and is capable of imparting low dielectric constants.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an organic polymer which is used for a wiring substrate or a semiconductor element and has excellent mechanical strength, adhesion to a substrate, crack resistance, uniformity of film thickness, and ability to form a thick film. Provided are a composite material with a silicon-containing metal composite oxide, and a precursor composition capable of forming a porous silicon-containing metal composite oxide having a large porosity and a low relative dielectric constant in addition to their physical properties. It is.

[0002]

2. Description of the Related Art Conventionally, a dense silicon oxide or a silicon oxide into which fluorine or an organic group is introduced has been used for an interlayer insulating film used for an LSI multilayer wiring. However, the relative dielectric constants of these materials are relatively large, and various problems such as wiring delay are caused by using these materials as an interlayer insulating film as LSI wiring becomes finer. For this reason, silicon oxide and an organic polymer are compounded to lower the relative dielectric constant, or silicon oxide is made porous to form a composite with air having a relative dielectric constant of about 1, thereby forming a dielectric constant. Attempts have been made to reduce rates.

Hrubesh et al. Reported that a wet gel obtained by hydrolyzing and dehydrating and condensing tetraalkoxysilane in alcohol was subjected to 110 bar in an autoclave.
Supercritical drying at 530K, relative dielectric constant of 1.1 to 1.9
Has been obtained as a porous silicon oxide thin film (Jour
nal of Material Research,
8 (7), p. 1736-1741 (1993)). According to Japanese Patent Application Laid-Open No. 7-185306, when producing a porous silicon oxide by supercritical drying as described above, a porous material having a high mechanical strength can be obtained by adding a metal compound composed of a metal other than silicon. A silicon-containing metal composite oxide is obtained. However, it is extremely difficult to apply a technique requiring a long-time treatment under a high temperature and a high pressure to the semiconductor manufacturing process.

[0004] JP-A-57-133119 discloses a composition containing an aluminum compound, a hydrolyzable silane compound and an epoxy resin. However, in this case, the aluminum compound and the silane compound are only added as catalysts, and the silane compound and the metal compound do not gel by reaction to form a network. A composite oxide cannot be obtained.

Further, Japanese Patent Publication No. 7-94326 discloses that
After dissolving a specific organic polymer in a solution containing alkoxysilanes, a hydrolysis reaction of alkoxysilanes is performed, and then a solution containing metal alkoxide is added to the solution, gelling is performed, and drying is performed. Then 500-8
A method for producing a porous silicon-containing metal composite oxide having strength and corrosion resistance by heating to 00 ° C. is disclosed. However, this method requires a high-temperature treatment of 500 ° C. or more, so that it cannot be used in a semiconductor manufacturing process. In addition, since the gelled material significantly shrinks during the high-temperature treatment, only a silicon dioxide porous material having a pore volume of about 0.16, that is, a dielectric constant of about 3.5 can be obtained. As described above, properties such as low dielectric constant, mechanical strength, adhesion to the substrate, crack resistance, uniformity of film thickness, and ability to form a thick film are essential for application to semiconductor devices. Before the present invention was made, it was extremely difficult to produce a porous material having the above characteristics by a method adaptable to a semiconductor production process.

[0006]

SUMMARY OF THE INVENTION The present invention relates to an insulating film for a semiconductor device and a precursor composition thereof, which are excellent in mechanical strength, adhesion to a substrate, crack resistance, uniformity of film thickness, and ability to form a thick film. About things.

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have conducted intensive studies, and as a result, surprisingly, the alkoxysilanes and the fourth, fifth, sixth, thirteenth, and A coating obtained by applying and gelling a composition comprising an aliphatic organic polymer and a metal compound comprising at least one or more metal elements other than silicon selected from Group 14; and removing the aliphatic organic polymer from the coating. The resulting porous silicon-containing metal composite oxide thin film is excellent not only in mechanical strength but also in adhesion to substrate and film thickness uniformity, thick film forming ability,
In addition, they have found that they have a low relative dielectric constant and are suitably used as insulating thin films for semiconductors, and have reached the present invention.

That is, the present invention relates to (1) (a) alkoxysilanes, (b) groups 4, 5, 6, 13, 14
A metal compound comprising at least one metal element other than silicon selected from the group consisting of: (c) an aliphatic organic polymer; and (2) a metal element contained in the metal compound is aluminum or titanium. , Zirconium, the composition according to (1), (3)
(1) The form of the metal compound is a metal alkoxide, a metal salt of an organic acid, or a metal complex of a diketone.
(4) The aliphatic organic polymer is characterized in that the aliphatic organic polymer is an aliphatic organic polymer containing aliphatic polyether, aliphatic polyester, aliphatic polycarbonate, and aliphatic polyanhydride as main components. (1) A composition obtained by applying the composition according to any one of the above (1) to (4) on a substrate and subjecting the alkoxysilane and the metal compound to hydrolysis and dehydration condensation. A transparent aliphatic organic polymer characterized by
A metal oxide composite thin film, (6) a porous silicon-containing metal composite obtained by removing the aliphatic organic polymer from the aliphatic organic polymer-metal oxide composite thin film according to (5). An oxide thin film; (7) a wiring structure using the thin film according to (5) or (6) as an insulator; and (8) a semiconductor including the wiring structure according to (7). Element.

Hereinafter, the present invention will be described in detail. The composition of the present invention is a composition comprising an alkoxysilane, a metal compound, and an aliphatic organic polymer. After the composition is coated on a substrate, the alkoxysilanes and the metal compound are hydrolyzed and dehydrated and condensed, whereby the alkoxy groups contained in the alkoxysilanes become hydroxyl groups, and subsequently cause a dehydration condensation reaction. On the other hand, the metal compound is also hydrolyzed to form a metal hydroxide and subsequently undergoes dehydration condensation, or the substituents and ligands contained in the metal compound are eliminated and condensed. As a result, a gel is formed, and a silicon-containing metal composite oxide thin film containing an aliphatic organic polymer is obtained.

The alkoxysilanes that can be used in the present invention include tetramethoxysilane, tetraethoxysilane, tetra (n-propoxy) silane, tetra (i-propoxy) silane, tetra (n-butoxy) silane, tetra ( and tetraalkoxysilanes such as (t-butoxy) silane. Also, an alkoxysilane oligomer, trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, bis (trimethoxysilyl) methane, bis (triethoxysilyl) Methane, 1,2-bis (trimethoxysilyl) ethane, 1,2-bis (triethoxysilyl) ethane, 1,4-bis (trimethoxysilyl) benzene, 1,4-bis (triethoxysilyl) benzene, etc. The alkoxysilanes having one hydrogen, an alkyl group or an aryl group on a silicon atom, such as represented by the formula (1), are also included in the alkoxysilanes used in the present invention. A partially hydrolyzed product of alkoxysilanes may be used as a raw material. These may be used alone or in combination of two or more.

Furthermore, in order to modify the resulting aliphatic organic polymer-metal oxide composite or porous silicon-containing metal composite oxide, two or three hydrogen, alkyl or aryl groups are added on the silicon atom. Can be mixed with the above-mentioned alkoxysilanes. The amount to be mixed is set to be 80 mol% or less of the total number of moles of the raw material silane compound. If it exceeds 80 mol%, gelation may not occur. As the metal compound used in the present invention, any compound can be used as long as it produces a metal oxide by a dehydration condensation reaction through hydrolysis or a condensation reaction by elimination of a substituent and / or a ligand. . Examples of metal atoms that can be suitably used include, for example, aluminum, titanium, zirconium, tin, germanium, tungsten, tantalum, and vanadium. Of these, aluminum, titanium and zirconium are particularly preferred.

Examples of the form of the metal compound include metal alkoxides having 1 to 6 carbon atoms such as methoxide, ethoxide, propoxide, butoxide and phenoxide, formic acid, acetic acid, propionic acid, oxalic acid, malonic acid, lactic acid, tartaric acid and the like. Metal salts of organic acids, alkyl acetoacetates, dialkyl malonates, acetylacetones, complexes of metals with diketones such as tetramethylheptanedione, hexafluoroacetylacetone, methanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfone Metal salts of sulfonic acids such as acids, metal salts of inorganic acids such as phosphoric acid, sulfuric acid, nitric acid, and carbonic acid, and other halides, cyanides, and alkylated compounds.
Hydrides, hydroxides, metal amides, quinolinates and the like. Among the above, alkoxides, salts of organic acids and diketone complexes are particularly preferred.

The metal compound may be composed of one type or two or more types for controlling the reactivity. These are determined by the type of metal atom contained in the metal compound and the likelihood of the above-mentioned hydrolysis reaction of alkoxysilane. The metal compound is used in an amount of 0.001 to 10 mol, preferably 0.1 mol, per 1 mol of silicon atom of the alkoxysilane used.
It is set so as to be in the range of 01 to 1 mol. When the content of the metal atom is less than 0.001 mol, the effect of the metal compound may not be obtained, and when the content is more than 10 mol, the gel may not be uniformly formed. The order in which the alkoxysilanes and the metal compound are added may be such that the metal compound is added after the alkoxysilanes are partially hydrolyzed, or vice versa, or the hydrolysis reaction may be started and proceed simultaneously. .

The aliphatic organic polymer used in the composition is not limited. Examples of the aliphatic organic polymer that can be preferably used include polyethers such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol, and polyethers. Acrylamide derivatives,
Amides such as polymethacrylamide derivatives, poly (N-vinylpyrrolidone) and poly (N-acylethyleneimine); esters such as polyvinyl alcohol, polyvinyl acetate, polyacrylic acid derivatives, polymethacrylic acid derivatives, and polycaprolactone; Examples include polyimides, polyurethanes, polyureas, polycarbonates, polyanhydrides, and the like. Further, a copolymer of monomers which are constituent components of these polymers or a copolymer with any other monomer may be used. The polymerization degree of the aliphatic organic polymer is selected from the range of 8 to 350,000. It is preferable that the basic skeleton of the polymer be an aliphatic one because it can be easily converted to a porous silicon-containing metal composite oxide by heating and sintering as described later. Preferred are aliphatic polyethers, aliphatic polyesters, aliphatic polycarbonates, and aliphatic polyanhydrides, and particularly preferred are polyethers such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

In order to increase the mechanical strength of the aliphatic organic polymer-metal oxide composite and to suppress shrinkage when converted to a porous silicon-containing metal composite oxide, an aliphatic organic polymer is used. It may have at least one polymerizable functional group in the molecule. In this case, the aliphatic organic polymer contained in the resulting aliphatic organic polymer-metal oxide composite has a three-dimensional network and / or graft-like structure. The functional groups used include a vinyl group,
Vinylidene group, vinylene group, glycidyl group, allyl group,
Examples include an acrylate group, a methacrylate group, an acrylamide group, a methacrylamide group, a carboxyl group, a hydroxyl group, an isocyanate group, an amino group, an imino group, and a halogen group. These functional groups may be in the main chain, at the terminal, or in the side chain of the polymer. Further, it may be directly bonded to the polymer chain, or may be bonded via a spacer such as an alkylene group or an ether group. The same polymer molecule may have one type of functional group, or may have two or more types of functional groups. Among the functional groups described above, vinyl, vinylidene, vinylene, glycidyl, allyl, acrylate, methacrylate, acrylamide, and methacrylamide groups are preferably used.

Specific examples of preferably used aliphatic organic polymers having a polymerizable functional group include polyethylene glycol acrylate, polyethylene glycol diacrylate, polyethylene glycol methacrylate, polyethylene glycol dimethacrylate, polyethylene glycol alkyl ether acrylate, and the like. Polyethylene glycol alkyl ether methacrylate, polyethylene glycol vinyl ether, polyethylene glycol divinyl ether, polyethylene glycol glycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol acrylate, polypropylene glycol diacrylate, polypropylene glycol methacrylate, polypropylene glycol dimethacrylate Acrylate, methacrylate, vinyl, glycidyl, glyceryl, propylene glycol alkyl ether acrylate, polypropylene glycol alkyl ether methacrylate, polypropylene glycol vinyl ether, polypropylene glycol divinyl ether, polypropylene glycol glycidyl ether, polypropylene glycol diglycidyl ether, etc. Such as aliphatic polyethers having a polymerizable functional group such as a group, polyglycidyl acrylate, polyglycidyl methacrylate, polyallyl acrylate, polyallyl methacrylate, polyvinyl acrylate, polyvinyl methacrylate, etc .; vinyl group, glycidyl group, allyl group in the side chain Polyacrylic acid having polymerizable functional groups such as Le and polymethacrylic acid esters, polyvinyl cinnamate, and epoxy resins.

Of these, polyethylene glycol acrylate, polyethylene glycol diacrylate, polyethylene glycol methacrylate, polyethylene glycol dimethacrylate, polyethylene glycol alkyl ether acrylate, polyethylene glycol, which can be easily converted to a porous silicon-containing metal composite oxide by heating and firing. Alkyl ether methacrylate,
Polyethylene glycol vinyl ether, polyethylene glycol divinyl ether, polyethylene glycol glycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol acrylate, polypropylene glycol diacrylate, polypropylene glycol methacrylate, polypropylene glycol dimethacrylate, polypropylene glycol alkyl ether acrylate, polypropylene glycol alkyl ether methacrylate, Particularly preferred are polypropylene glycol vinyl ether, polypropylene glycol divinyl ether, polypropylene glycol glycidyl ether, and polypropylene glycol diglycidyl ether.

The amount of the aliphatic organic polymer added is 10 ^-2 to 1 based on 1 part by weight of the total of the alkoxysilane and the metal compound.
00 parts by weight, preferably 10 ^-1 to 10 parts by weight, more preferably 10 ^{-1 to} 5 parts by weight. When the amount of the organic polymer is less than 10 ^-2 parts by weight, the strength of the composite does not increase, and the porosity of the porous silicon-containing metal composite oxide obtained therefrom also decreases. However, the properties of the composite do not appear, and the strength of the obtained porous silicon-containing metal composite oxide is low, which is not practical. Instead of the aliphatic organic polymer, a polymerizable organic monomer can be used as a starting material. In this case, any polymerizable monomer may be used. However, when a bifunctional monomer is contained in the organic monomer, the polymer in the obtained composite has a three-dimensional network and / or Or it becomes a graft-like structure.

[0019] Examples of those which can be preferably used include:
Acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, acrylic acid and methacrylic acid derivatives such as ethylene bis acrylate, ethylene bis methacrylate, α-cyano acrylic acid, α-cyano acrylic acid ester, vinyl acetate, vinyl propionate, Acid vinyl esters such as vinyl crotonate, vinyl benzoate and vinyl chloroformate, acrylamide, methacrylamide, N, N-dialkylacrylamide, N, N-dialkylmethacrylamide, N-alkylacrylamide, N-alkylmethacrylamide, N Amides such as N, N'-methylenebisacrylamide, N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, styrene, α-methylstyrene, p-methoxystyrene, diphenyle Tylene, vinylnaphthalene, vinylanthracene, vinylcyclopentane, vinylcyclohexane, vinyl group-containing hydrocarbons such as 5-vinyl-2-norbornene, acrylonitrile derivatives such as acrylonitrile and methacrylonitrile, N-vinylpyridine, N-vinylcarbazole And vinylamines such as N-vinylimidazole, vinyl alkyl ethers, vinyl alkyl ketones, glycidyl acrylate, glycidyl methacrylate, and epoxy resins.

These aliphatic organic polymers and polymerizable organic monomers may be used alone or in combination of two or more. Of course, an aliphatic organic polymer and a polymerizable organic monomer can be used in combination. The amount of the polymerizable organic monomer to be added is 10 ^{-2 to} 100 parts by weight, preferably 10 ^-2 parts by weight, based on 1 part by weight of the total of the alkoxysilane and the metal compound.
^-1 to 10 parts by weight, more preferably 10 ^{-1 to} 5 parts by weight, and when the aliphatic organic polymer and the polymerizable organic monomer are used in combination, the total amount is within the above range.

When an aliphatic organic polymer having a polymerizable functional group or a polymerizable organic monomer is used, a polymerization initiator may be added in order to promptly proceed the polymerization reaction. Known polymerization initiators include thermal radical generators such as azo compounds and organic peroxides, photoradical initiators such as diazo compounds, azide compounds and acetophenone derivatives, as well as photoacid generators and photobase generators. Can be used. These may be used alone or in combination of two or more. Thermal polymerization and photopolymerization using an initiator are performed by a known method. The amount of the polymerization initiator is set to 10 ^-3 to 1 part by weight, preferably 10 ^-2 to 10 ^-1 part by weight based on ¹ part by weight of the aliphatic organic polymer having a polymerizable functional group and the polymerizable organic monomer. .

In the composition of the present invention, the presence of a solvent is not always essential. However, in general, the alkoxysilanes or metal compounds are hardly compatible with the aliphatic organic polymer. is necessary. Any solvent can be used without particular limitation as long as it can dissolve alkoxysilanes, metal compounds, and aliphatic organic polymers. Even if the raw material alkoxysilanes and metal compounds are insoluble, they can be used as long as they become soluble after hydrolysis. The amount of the solvent used is set so that the total concentration of the alkoxysilane, the metal compound, the aliphatic organic polymer and the organic monomer is 0.05% by weight or more.
If the concentration is lower than this, gelation does not occur, and a practical coating film cannot be obtained.

Examples of the solvent used include those having 1 to 1 carbon atoms.
4, monohydric alcohols, dihydric alcohols having 1 to 4 carbon atoms,
In addition to alcohols such as glycerin, formamide, N
-Methylformamide, N-ethylformamide, N,
N-dimethylformamide, N, N-diethylformamide, N-methylacetamide, N-ethylacetamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methylpyrrolidone, N-formylmorpholine, N-acetylmorpholine Amides such as N-formylpiperidine, N-acetylpiperidine, N-formylpyrrolidine, N-acetylpyrrolidine, N, N'-diformylpiperazine, N, N'-diacetylpiperazine, tetramethylurea, N, N ' Ureas such as dimethylimidazolidinone, tetrahydrofuran, diethyl ether, di (n-propyl) ether, diisopropyl ether, diglyme, 1,4-dioxane, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether Ethers such as ethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol dimethyl ether, ethyl formate, methyl acetate, ethyl acetate, butyl acetate, isoamyl acetate, ethyl lactate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene Glycol diacetate, propylene glycol monomethyl ether acetate, diethyl carbonate, ethylene carbonate, esters such as propylene carbonate, acetone, methyl ethyl ketone,
Methyl propyl ketone, methyl (n-butyl) ketone,
Ketones such as methyl isobutyl ketone, methyl amyl ketone, cyclopentanone and cyclohexanone, nitriles such as acetonitrile, propionitrile, n-butyronitrile and isobutyronitrile, dimethyl sulfoxide, dimethyl sulfone, sulfolane and the like are preferably used. . These solvents may be mixed, or any other solvent or additive may be mixed.

Among the above-mentioned solvents, formamide, N
-Methylformamide, N-ethylformamide, N,
N-dimethylformamide, N, N-diethylformamide, N-methylacetamide, N-ethylacetamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methylpyrrolidone, N-formylmorpholine, N-acetylmorpholine Amides such as N-formylpiperidine, N-acetylpiperidine, N-formylpyrrolidine, N-acetylpyrrolidine, N, N'-diformylpiperazine, N, N'-diacetylpiperazine, tetramethylurea, N, N ' It is particularly preferred to use ureas such as -dimethylimidazolidinone.

In the present invention, a catalyst is not necessarily required for the hydrolysis and dehydration condensation of alkoxysilanes and metal compounds, but a catalyst may be added to accelerate the reaction. Specific examples of the catalyst include hydrochloric acid, nitric acid, sulfuric acid, formic acid,
Acids such as acetic acid, oxalic acid, and maleic acid, aqueous ammonia, potassium hydroxide, sodium hydroxide, triethylamine,
Alkalis such as triethanolamine, pyridine, piperidine and choline; These may be used alone or in combination of two or more. It is also possible to use two or more kinds in a stepwise manner. The term “stepwise” as used herein refers to, for example, performing a treatment with an acid catalyst in advance and then adding a base catalyst, or vice versa. The addition amount of these catalysts is 1 mol or less, preferably 10 ^-1 mol or less, per 1 mol of the total of the alkoxysilane and the metal compound. If it is more than 1 mol, a precipitate may be formed, and a uniform porous body may not be obtained.

In the present invention, the hydrolysis of alkoxysilanes and metal compounds is caused by water as a solvent when the catalyst is an aqueous solution, and sufficient water vapor exists in the surroundings without adding water. If so, you can use it. If necessary, water may be separately added. An appropriate amount of water is 0.3 to 10 ⁴ moles, preferably 1 to 10 moles per 1 mole of the total of silicon atoms contained in the raw material alkoxysilane and metal atoms contained in the metal compound.
10 moles. If the amount is more than 10 ⁴ mol, the homogeneity of the obtained composite may decrease. After the composition of the present invention is applied on a substrate and then gelled, an aliphatic organic polymer-metal oxide composite thin film can be obtained. As a method of applying the film, a known method such as casting, rotation, and immersion can be used. The thickness of the thin film composed of the aliphatic organic polymer-metal oxide composite is 0.1 μm.
m to 10 μm. If the thickness is more than 10 μm, cracks may occur.

The surface of the substrate may be treated in advance with an adhesion improver. In this case, as the adhesion improver, a compound used as a so-called silane coupling agent, an aluminum chelate compound, or the like can be used. Particularly preferably used are 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3
-Aminopropylmethyldimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropylmethyldichlorosilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropylmethyldiethoxysilane, 3 -Mercaptopropyltrimethoxysilane, 3-
Glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, hexamethyldisilazane, ethyl acetoacetate aluminum diisopropylate, aluminum Tris (ethyl acetoacetate), aluminum bis (ethyl acetoacetate)
Monoacetyl acetonate, aluminum tris (acetyl acetonate) and the like can be mentioned. When applying these adhesion improvers, other additives may be added as necessary, or they may be diluted with a solvent before use. The treatment with the adhesion improver is performed by a known method.

The temperature of the gelation reaction is not particularly limited, but is usually 0 to 180 ° C., preferably 30 to 150 ° C.
Perform in the range of ° C. If it is too low, the reaction rate is slow, and it takes a long time to sufficiently crosslink, while if it is too high, voids are liable to be formed, and the homogeneity of the resulting aliphatic organic polymer-metal oxide composite decreases. The time required for gelation varies depending on the gelling temperature, the amount of catalyst, and the like, but is usually in the range of several minutes to several days.

When an aliphatic organic polymer having a polymerizable functional group or a polymerizable organic monomer is used in the present invention, it is preferable to polymerize these. This reaction may proceed before, simultaneously with or after the alkoxysilane or metal compound gels. The order of these reactions varies depending on the type and amount of the catalyst and the reaction conditions. The polymerization reaction using a functional group here means general addition, polyaddition, addition condensation, ring opening, polycondensation reaction and the like. The polymerization reaction using the functional group in the aliphatic organic polymer can be promoted by heating. The temperature is selected from the range of 20 to 200 ° C. according to the type of the functional group contained in the aliphatic organic polymer. In addition, if the organic polymer used is a photocrosslinkable one, the reaction can be advanced by light irradiation. A polymerization initiator may be added in order to promptly advance the polymerization reaction. Known polymerization initiators include thermal radical generators such as azo compounds and organic peroxides, photoacid generators such as diazo compounds, azide compounds, and acetophenone derivatives, as well as photoacid generators and photobase generators. Can be used. These may be used alone or in combination of two or more. Thermal polymerization and photopolymerization using an initiator are performed by a known method. The amount of the polymerization initiator is 10 ⁻³ to 1 part by weight of the aliphatic organic polymer.
1 part by weight, preferably 10 ^-2 to 10 ^-1 part by weight is used.

When a gelation reaction of an alkoxysilane or a metal compound is carried out in a closed system using the composition of the present invention containing a solvent, a complex containing the solvent is obtained. It is necessary to dry. The drying temperature depends on the type of the solvent, but is usually from 30 to 250.
Perform in the range of ° C. Drying under reduced pressure is also effective. In order to control the generation of voids and obtain a uniform dried gel, a method of gradually increasing the temperature during the drying step is also preferable. When the present invention is carried out in an open system using a solvent, evaporation of the solvent occurs in parallel with the above-mentioned gelling reaction of the alkoxysilane or the metal compound. The order of the reaction and the removal of the solvent can be controlled by selecting the type of the silane compound as the raw material, the type and amount of the catalyst, the vapor pressure of the solvent, the atmosphere of the closed system or the open system, and the like. In the case of producing a thin film according to the present invention, the solvent is removed at the time when the gelling reaction of the alkoxysilane or the metal compound is completed under normal conditions.

The composite thin film obtained by using the composition of the present invention has high mechanical strength, adhesion to a substrate, uniformity of film thickness, and ability to form a thick film. It has excellent properties that are not available. Further, by removing only the aliphatic organic polymer from the composite, it can be converted to a porous silicon-containing metal composite oxide. The simplest method for removing the aliphatic organic polymer is a method in which the organic polymer is heated at a temperature equal to or higher than the thermal decomposition temperature of the organic polymer for about 1 minute to 24 hours. In addition, the aliphatic organic polymer can be removed by photolysis, plasma treatment, or a combination thereof.

It is also effective to treat the obtained porous silicon-containing metal composite oxide with a silylating agent to suppress water absorption and improve the adhesion to other substances. Examples of silylating agents that can be used include trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethylethoxysilane, methyldiethoxysilane, dimethylvinyl Methoxysilane, dimethylvinylethoxysilane,
Alkoxysilanes such as diphenyldimethoxysilane, diphenyldiethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, methyldichlorosilane, dimethylchlorosilane, dimethylvinylchlorosilane, methylvinyldichlorosilane Chlorosilanes such as methylchlorodisilane, triphenylchlorosilane, methyldiphenylchlorosilane, diphenyldichlorosilane, hexamethyldisilazane, N, N'-bis (trimethylsilyl) urea;
Silazanes such as N-trimethylsilylacetamide, dimethyltrimethylsilylamine, diethyltriethylsilylamine, and trimethylsilylimidazole. The silylation method is performed by a method such as coating, dipping, and steam exposure.

The composite thin film of the silicon-containing metal composite oxide and the aliphatic organic polymer of the present invention has excellent mechanical strength, adhesion to a substrate, crack resistance, uniform thickness, and ability to form a thick film. Therefore, it can be used for a wide range of applications such as optical materials such as lenses, structural materials, films and coating materials. In addition, since the composite thin film has a lower relative dielectric constant and a superior ability to form a thick film as compared with a silicon oxide thin film obtained using only alkoxysilane, it should be used as it is as an insulating portion of a wiring of a semiconductor element or the like. Is possible. However, for the purpose of obtaining a material having a lower relative dielectric constant, it is more preferable to convert the material into a porous silicon-containing metal composite oxide thin film. The porous silicon-containing metal composite oxide is also excellent in mechanical strength, adhesion to a substrate, crack resistance, film thickness uniformity, and ability to form a thick film, and has a low relative dielectric constant. The film can be used for an LSI multilayer wiring substrate or a semiconductor element.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described more specifically below with reference to embodiments of the present invention. The evaluation of the composite and the porous silicon-containing metal composite oxide was performed using the following apparatus,
Performed using the method. (1) Adhesion (tensile strength) measurement: Titanium was formed on the film by sputtering with a film thickness of 10 nm, and a tack was adhered on the titanium film with epoxy resin to prepare five samples, and a tensile test was performed. Evaluation was made as an average value of five samples on a machine. The measurement temperature is 25 ° C. (2) Indentation indentation measurement: Micro hardness tester manufactured by Shimadzu Corporation
Using 201S, it was determined from the average value of the indentation depth when a load of 0.05 g weight was applied to five arbitrary points on the sample with a diamond tip having a vertex angle of 115 degrees. The measurement temperature is 25 ° C.

(3) Measurement of film thickness: Ten points on the film were scratched with a cutter knife to expose the underlying wafer, and at each point, the surface was measured with a DEKTAK-IIA type surface roughness measuring device manufactured by Sloan. The depth was measured and calculated as the average value. (4) Measurement of dielectric constant: HP manufactured by Hewlett-Packard Company
It measured using the 4280 type CV measuring device. (5) Transparency: Slice the composite to a thickness of 1 mm, place it on a dial with 3 mm square black letters written on a white background,
If the characters were legible through the complex, it was judged to be transparent.

[0036]

Example 1 0.67 g of methyltrimethoxysilane, 0.20 of aluminum tris (ethylacetoacetate)
g, 0.42 g of polyethylene glycol monomethacrylate (average molecular weight 360) and 0.10 g of polyethylene glycol dimethacrylate (average molecular weight 540) of methanol 1.0 g, N-methylpyrrolidone 0.3 g, and propylene glycol methyl ether acetate 0.2 g. Dissolve in a mixed solvent and add 0.30 g of water and 0.1 N
0.15 g of sulfuric acid was added, and the mixture was stirred at room temperature for 2 hours. To this solution was added 0.05 g of dicumyl peroxide, and a silicon nitride thin film was formed on a 6-inch silicon wafer previously formed by chemical vapor deposition at a speed of 1500 revolutions per second.
Spin-applied for seconds. 1 on the hot plate
After heating at 20 ° C. for 3 minutes, the mixture was heated at 200 ° C. for 1 hour and then at 450 ° C. for 1 hour under a nitrogen atmosphere. When a tensile strength test was performed on this sample, the tensile strength was 78 MPa. The indenter indentation test showed that the hardness was 562 MPa and the elastic modulus was 6.00 GPa.

[0037]

Comparative Example 1 The same operation as in Example 1 was performed except that aluminum tris (ethyl acetoacetate) was not used, and the tensile strength was 39 MPa and the hardness was 3
It was 28 MPa and the elastic modulus was 3.71 GPa.

[0038]

Example 2 0.67 g of methyltrimethoxysilane, 0.20 of aluminum tris (ethylacetoacetate)
g, 0.52 g of polypropylene glycol diglycidyl ether (average molecular weight: 400)
g, 0.3 g of N-methylpyrrolidone and 0.2 g of propylene glycol methyl ether acetate, and 0.30 g of water and 0.15
g was added and stirred at room temperature for 2 hours. This solution was spin-coated on a 6-inch silicon wafer at a speed of 1500 revolutions per second for 10 seconds. In addition, 12
After heating at 0 ° C. for 3 minutes, and then heating at 200 ° C. for 1 hour and then at 450 ° C. for 1 hour under a nitrogen atmosphere, a flat, crack-free porous silicon-aluminum composite oxide thin film was obtained. Was done. Further, for the composition, using a silicon wafer with a silicon nitride thin film, a sample was prepared by performing exactly the same operation as in Example 1, and a tensile strength test and an indenter indentation test were performed. Elastic modulus 3.50 GPa
Met.

[0039]

Comparative Example 2 The same operation as in Example 2 was carried out except that aluminum tris (ethyl acetoacetate) was not used. As a result, the solution on the edge of the silicon wafer was repelled at the time of coating, and the film was stuck. In addition, the film was mottled also in other portions, and the film thickness was significantly lacking in uniformity.

[0040]

Example 3 0.67 g of methyltrimethoxysilane, 0.20 of aluminum tris (ethylacetoacetate)
g, polyethylene glycol (average molecular weight: 400)
52 g was dissolved in a mixed solvent of 1.0 g of methanol, 0.3 g of N-methylpyrrolidone and 0.2 g of propylene glycol methyl ether acetate, and 0.3 g of water was added to this solution.
0 g and 0.15 g of 0.1 N sulfuric acid were added, and the mixture was stirred at room temperature for 2 hours. This solution is applied to a 6-inch silicon wafer at 1
Spin coating was performed at a speed of 000 revolutions for 10 seconds. Further, after heating at 120 ° C. for 3 minutes in the air on a hot plate, and then heating at 200 ° C. for 1 hour and then at 450 ° C. for 1 hour in a nitrogen atmosphere, a flat, crack-free porous material having a thickness of 1.3 μm was obtained. A thin film of a composite oxide of silicon and aluminum was obtained. Further, for the composition, using a silicon wafer with a silicon nitride thin film, a sample was prepared by performing exactly the same operation as in Example 1, and a tensile strength test and an indenter indentation test were performed.
The hardness was 622 MPa and the elastic modulus was 4.82 GPa.

[0041]

Comparative Example 3 The same operation as in Example 3 was performed except that aluminum tris (ethyl acetoacetate) was not used. As a result, the film on the silicon wafer was white, and this was observed with a microscope. However, minute cracks occurred on the entire surface.

[0042]

Example 4 The solution used in Example 1 and Comparative Example 1 was
Titanium nitride was spin-coated at a rate of 1500 revolutions per second for 10 seconds on a 6-inch silicon wafer on which a film of titanium nitride had been formed in advance. Furthermore, on a hot plate in air at 120 ° C
, And then heated at 200 ° C. for 1 hour and then at 450 ° C. for 1 hour under a nitrogen atmosphere. Aluminum metal was deposited on these films through a mask, and had a diameter of 1.7.
mm electrode was prepared and the relative dielectric constant was measured. As a result, 2.06 was obtained for Example 1 and 2.1 for Comparative Example 1.
It was 5. In each case, the results were lower than the relative dielectric constant of methylsilsesquioxane of 3.0, and the results were lower when the aluminum compound was added than when it was not added.

[0043]

Example 5 The solution used in Examples 1 to 3 was cast on a polytetrafluoroethylene watch glass and heated in air at 120 ° C. for 1 hour and then at 180 ° C. for 1 hour to obtain an organic polymer. A metal oxide composite was obtained. These were all transparent.

[0044]

According to the present invention, a composite thin film of a silicon-containing metal composite oxide and an organic polymer having excellent mechanical strength, adhesion to a substrate, crack resistance, uniformity of film thickness, and ability to form a thick film. Was obtained. In addition, the porous silicon-containing metal composite oxide thin film obtained from the composite thin film is also superior in mechanical strength, adhesiveness to a substrate, uniformity of film thickness, and ability to form a thick film than conventional ones, In addition, since a material having a low dielectric constant can be obtained, it can be suitably used as an insulating film for LSI multilayer wiring, and is very useful in industry.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 69/00 C08L 69/00 71/02 71/02 73/00 73/00 H01L 21/31 H01L 21 / 31 A 21/316 21/316 G // H01B 3/12 336 H01B 3/12 336 H01L 21/768 H01L 21/90 SQ F term (reference) 4J002 BE021 BF021 BG011 BG131 BJ001 CF191 CG011 CH021 CJ001 CK011 CK021 CM011 CM041 DB007 DD007 DD077 DE097 DE247 DF027 DF037 DG047 DH047 EC077 EG047 EV257 EX036 EZ007 GQ05 5F033 QQ74 RR03 RR21 RR26 SS22 XX12 XX23 5F045 AB40 AF08 BB02 BB17 CB05 BB20 BA16 BA02 BA04 BA02 BA04 CD04

Claims (8)

[Claims] (1) alkoxysilanes, (b) 4
A metal compound comprising at least one metal element other than silicon selected from Group 5, Group 5, Group 6, Group 13, and Group 14,
(C) a composition for a semiconductor device comprising an aliphatic organic polymer. 2. The composition according to claim 1, wherein the metal element contained in the metal compound is aluminum, titanium, or zirconium. 3. The composition according to claim 1, wherein the form of the metal compound is a metal alkoxide, a metal salt of an organic acid, or a metal complex of a diketone. 4. The aliphatic organic polymer is an aliphatic polyether, an aliphatic polyester, an aliphatic polycarbonate,
The composition according to claim 1, wherein the composition is an aliphatic organic polymer containing aliphatic polyanhydride as a main component. 5. A transparent aliphatic organic material obtained by applying the composition according to claim 1 on a substrate and subjecting the composition to hydrolysis and dehydration condensation of an alkoxysilane and a metal compound. Polymer-metal oxide composite thin film. 6. The aliphatic organic polymer according to claim 5,
A porous silicon-containing metal composite oxide thin film obtained by removing an aliphatic organic polymer from a metal oxide composite thin film. 7. A wiring structure using the thin film according to claim 5 as an insulator. 8. A semiconductor device including the wiring structure according to claim 7.