JP2006104478A - Coating solution for forming oxide coating film and method for producing oxide film and semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating solution that can form a coating film having excellent coating uniformity and high thermal stability, to provide a method for producing uniform and thermally stable oxide coating film and further a method for producing a semiconductor device having the uniform and thermally stable oxide coating film. <P>SOLUTION: The coating solution for forming the oxide coating film is produced by hydrolyzing and polycondensing an alkoxysilane represented by general formula (I) (wherein R is a 1-4 C alkyl, R' is a 1-3C alkyl, m is 0, 1 or 2) in the presence of a solvent and removing the monohydric alcohol formed during the hydrolysis. The coating solution is applied to the surface of semiconductor elements, then dried at 50 to 200°C, followed by firing at 300 to 1,000°C, thereby producing semiconductor devices having oxide coating film. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coating liquid for forming an oxide film, an oxide film, and a method for manufacturing a semiconductor device.

  2. Description of the Related Art Conventionally, as a method for interlayer insulation of semiconductor elements such as IC and LSI, a method of forming an oxide film by hydrolyzing a silanol compound and baking a condensate is often used. The method using tetrafunctional silanes such as tetraethoxysilane is the most widely known, but in the method using only tetrafunctional silane, the three-dimensional cross-linking structure becomes very dense and rigid when fired to form a silica-based film. Therefore, there is a problem that cracks occur when the film thickness increases. In order to solve this problem, a method of cohydrolyzing bifunctional and trifunctional silanes is disclosed in Patent Document 1 and the like.

These methods are generally called sol-gel methods, and a coating solution for forming a film is prepared using alkoxysilane (alkoxy group having 1 to 3 carbon atoms) as a starting material and prepared using water and a catalyst in the presence of a solvent. Then, after spin coating on a substrate such as LSI, heat treatment at about 450 ° C. is performed to form an oxide film. However, the coating solutions prepared by these methods have the disadvantage that the uniformity of the film thickness is reduced during spin coating, and the processability is poor in the subsequent semiconductor manufacturing process.
JP 57-191219 A

  The invention described in claims 1 and 2 provides a coating liquid for forming an oxide film that is excellent in coating uniformity and can form a thermally stable oxide film. The invention according to claim 3 provides a coating solution for forming an oxide film that is more excellent in coating uniformity. The invention according to claim 4 provides a method for producing a uniform and thermally stable oxide film. The invention according to claim 5 provides a method of manufacturing a semiconductor device having a uniform and thermally stable oxide film.

（式中Ｒは、炭素数１〜４のアルキル基、Ｒ′は炭素数１〜３のアルキル基、ｍは０、１または２を意味する）で表されるアルコキシシラン化合物を溶媒の存在下に加水分解及び縮重合させ、加水分解によって生成する１価アルコールを除去してなる酸化物被膜形成用塗布液に関する。本発明は、また、上記の酸化物被膜形成用塗布液において、溶媒の沸点が加水分解で生成する１価アルコールの沸点より３０℃以上高いものである酸化物被膜形成用塗布液に関する。 The present invention relates to (A) the general formula (I)

(Wherein R represents an alkyl group having 1 to 4 carbon atoms, R 'represents an alkyl group having 1 to 3 carbon atoms, and m represents 0, 1 or 2). It is related with the coating liquid for oxide film formation formed by removing the monohydric alcohol produced | generated by hydrolysis and polycondensation to hydrolysis. The present invention also relates to the coating solution for forming an oxide film, wherein the boiling point of the solvent is 30 ° C. or more higher than the boiling point of the monohydric alcohol generated by hydrolysis.

  Furthermore, this invention relates to the manufacturing method of the oxide film characterized by drying these coating liquids on a substrate surface, drying at 50-200 degreeC, and baking at 300-1000 degreeC. The present invention also provides a semiconductor device characterized in that these coating liquids are applied onto the surface of a semiconductor element, dried at 50 to 200 ° C., and then fired at 300 to 1000 ° C. to form an oxide film. It relates to the manufacturing method.

  The coating solution for forming an oxide film according to claims 1 and 2 is excellent in coating uniformity. This coating solution is effective for flattening the surface of an element such as an interlayer gap film in an electronic component, particularly a semiconductor multilayer wiring, and a magnetic bubble memory. The coating liquid for forming an oxide film according to claim 3 is further excellent in coating uniformity. According to the method for producing an oxide film in claim 4, a uniform film free from cracks can be obtained even with a thickness of about 1.5 μm. According to the method for manufacturing a semiconductor device in claim 5, a semiconductor device having the above excellent oxide film can be manufactured.

等のテトラアルコキシシラン、

等のモノアルキルトリアルコキシシラン、

等のジアルキルジアルコキシシランが挙げられ、これらは１種または２種以上が用いられる。 The alkoxysilane compound used in the present invention is represented by the general formula (I), and specifically,

Tetraalkoxysilane, etc.

Monoalkyltrialkoxysilane such as

Dialkyl dialkoxysilanes such as these are used, and one or more of these are used.

  Although there is no restriction | limiting in particular in the ratio of the said alkoxysilane compound used for this invention, in order to improve the crack resistance of the oxide film obtained, a tetraalkoxysilane compound is 50-80 mol%, a trialkoxysilane compound is used. A range of 10 to 20 mol% and a dialkoxysilane compound of 10 to 40 mol% are preferable.

  Examples of the solvent used in the present invention include acetate esters such as isopropyl acetate and isobutyl acetate, glycol acetate solvents such as ethylene glycol monomethyl acetate and ethylene glycol diacetate, N, N-dimethylacetamide, N, N-dimethylformamide, Various solvents such as an amide solvent such as N-methyl-2-pyrrolidone and a glycol ether solvent may be used, and one or more of these may be used. The boiling point of the solvent is preferably 100 ° C. or higher from the viewpoint that there is no unevenness in the film thickness obtained by coating. Further, the solvent has a boiling point of 30 ° C. or higher than the boiling point of the monohydric alcohol produced by hydrolysis. This is preferable because alcohol can be easily removed by distillation.

  In the hydrolysis and polycondensation in the present invention, as a catalyst, an inorganic acid such as hydrochloric acid, sulfuric acid, phosphoric acid, boric acid, hydrofluoric acid or nitric acid, or an organic acid such as oxalic acid, maleic acid, sulfonic acid or formic acid is used. preferable. The catalyst is preferably 0.0001 to 0.01 mol% with respect to 1 mol of the alkoxysilane compound. In addition, water needs to be present in the hydrolysis, but it is preferably used in an amount of 0.5 to 2 moles with respect to 1 equivalent of the alkoxy group in the alkoxysilane compound.

  The coating solution for forming an oxide film of the present invention is produced by hydrolysis and polycondensation of an alkoxysilane compound using water and a catalyst in the presence of the above-mentioned solvent, and hydrolysis at a temperature of 100 ° C. or lower under reduced pressure. Compared with the coating liquid obtained by hydrolyzing and condensing a conventional alkoxysilane compound and these and a metal alkoxide compound by removing the monovalent alcohol to keep the solvent of the coating liquid uniform. The uniformity is very good. The monohydric alcohol can be removed by distillation by heating or heating under reduced pressure.

  Next, in order to form an oxide film using the coating solution thus obtained, the coating solution is immersed on a substrate such as glass, ceramics, silicon wafer, or silicon wafer on which a circuit is formed. After coating by a method such as spin coating, it is usually dried at 50 to 200 ° C., preferably 100 to 150 ° C., and then fired at 300 to 1000 ° C., preferably 300 to 450 ° C. The thickness of the oxide film to be formed is preferably 0.2 to 0.5 μm. As a semiconductor device on which an oxide film may be formed, there is a silicon wafer or the like on which an aluminum wiring is formed, and the wiring may have a multilayer wiring structure.

Action:
In order to form an oxide film that does not generate cracks on a substrate such as silicon or aluminum using a coating liquid for forming an oxide film containing an alkoxysilane compound, (1) the curing shrinkage strain during firing is reduced, (2) It is necessary to use a coating solution that satisfies the condition that the thermal expansion coefficient of the film is close to the value of the substrate. Such a coating solution has a low boiling point of 1 generated by hydrolysis during the production of the coating solution. It is obtained by maintaining the uniformity of the solvent by removing the hydric alcohol.

Hereinafter, the present invention will be described in detail with reference to examples.
Example 1
152.0 g of Si (OCH ₃ ) _{4 and} 136.0 g of CH ₃ Si (OCH ₃ ) ₃ were dissolved in 900 g of propylene glycol monopropyl ether, and 63.0 g of water in which 2.0 g of nitric acid was dissolved was added to this solution. Hydrolysis and condensation were carried out at room temperature for 10 hours, followed by treatment at 20 ° C. for 2 hours in a distillation apparatus controlled to a reduced pressure of 2 mmHg to remove methyl alcohol produced by hydrolysis from the coating solution. As a result of measuring the residual amount of methyl alcohol in this reactant solution with a gas chromatograph (Hitachi 263-50 type), it was 0.1 wt% or less in the reactant solution. The heating residue of the obtained coating solution was 15% by weight.

  The coating solution prepared here was applied onto a 6-inch silicon wafer at 2000 rpm using a spinner, dried on a hot plate controlled at 150 ° C. and 250 ° C. for 1 minute each, and then 400 ° C. in an electric furnace. When baked for 1 hour, a colorless transparent film without cracks was obtained. The thickness of the oxide film formed on the wafer was measured at 10 points with an interference film thickness meter (Lambda Ace, manufactured by Dainippon Screen) and found to be 0.50 ± 0.01 μm. Further, the solution is formed on a silicon wafer on which an aluminum wiring having a thickness of 1.0 μm and a line & space width of 0.5 to 5.0 μm is formed under the same conditions as described above to form a pattern around the wafer. When the film thickness of the portion that was applied was measured in the same manner as described above, the film thickness was 0.50 ± 0.02 μm.

(Comparative Example 1)
264.0 g of Si (OC ₂ H ₅ ) ₄ was dissolved in 600 g of ethyl alcohol, and 80 g of water in which 4.0 g of maleic acid was dissolved was added to this solution, followed by hydrolysis and condensation to prepare a reactant solution. The coating solution prepared here was applied onto a 6-inch silicon wafer at 2000 rpm using a spinner, dried on a hot plate controlled at 150 ° C. and 250 ° C. for 1 minute each, and then 400 ° C. in an electric furnace. When baked for 1 hour, a colorless transparent film without cracks was obtained. When the thickness of the oxide film formed on the wafer was measured at 10 points with an interference film thickness meter (Lambda Ace, manufactured by Dainippon Screen), it was 0.45 ± 0.50 μm.

  Further, the solution is formed on a silicon wafer on which an aluminum wiring having a thickness of 1.0 μm and a line & space width of 0.5 to 5.0 μm is formed under the same conditions as described above to form a pattern around the wafer. When the film thickness of the portion that was applied was measured in the same manner as described above, the film thickness was 0.45 ± 0.75 μm.

(Comparative Example 2)
152.0 g of Si (OCH ₃ ) _{4 and} 136.0 g of CH ₃ Si (OCH ₃ ) ₃ were dissolved in 600 g of propylene glycol monopropyl ether, and 63.0 g of water in which 2.0 g of maleic acid was dissolved was added to this solution. Then, hydrolysis and condensation were performed to prepare a reaction product solution.

  The coating solution prepared here was applied onto a 6-inch silicon wafer at 2000 rpm using a spinner, dried on a hot plate controlled at 150 ° C. and 250 ° C. for 1 minute each, and then 400 ° C. in an electric furnace. When baked for 1 hour, a colorless transparent film without cracks was obtained. When the thickness of the oxide film formed on the wafer was measured at 10 points with an interference film thickness meter (Lambda Ace, manufactured by Dainippon Screen), it was 0.47 ± 0.01 μm. Further, the solution is formed on a silicon wafer on which an aluminum wiring having a thickness of 1.0 μm and a line & space width of 0.5 to 5.0 μm is formed under the same conditions as described above to form a pattern around the wafer. When the film thickness of the portion that was applied was measured in the same manner as described above, the film thickness was 0.47 ± 0.20 μm.

Claims (5)

Formula (I)

(Wherein R represents an alkyl group having 1 to 4 carbon atoms, R 'represents an alkyl group having 1 to 3 carbon atoms, and m represents 0, 1 or 2). Is a coating liquid for forming an oxide film obtained by removing monohydric alcohol produced by hydrolysis and condensation polymerization, and the residual amount of monohydric alcohol in the solution is 0.1% by weight or less. Coating liquid for forming a physical film [However, (A) (1) Dialkoxy having one or two of a phenyl group and an alkyl group having 1 to 3 carbon atoms and an alkoxy group having 1 to 4 carbon atoms Silane, (2) Phenyltrialkoxysilane or methyltrialkoxysilane having an alkoxy group having 1 to 4 carbon atoms, (3) Inorganic acid or PKa which does not contain a metal and contains at least one of chlorine atom and phosphorus atom The value is 0 Intrinsic viscosity at 25 ° C. obtained by dehydration condensation of a mixture of an organic acid of 8 to 6 and (4) water or a water-soluble organic solvent excluding aliphatic monohydric alcohol under heating. Is 0.1-10 cm ³ / g silicone oligomer, (B) an aliphatic monohydric alcohol or a mixed solvent containing the same, and (C) a condensation catalyst containing a metal atom]. Formula (I)

(Wherein R represents an alkyl group having 1 to 4 carbon atoms, R 'represents an alkyl group having 1 to 3 carbon atoms, and m represents 0, 1 or 2). A coating solution for forming an oxide film, wherein the monohydric alcohol produced by hydrolysis is essentially removed by the hydrolysis and condensation polymerization of [(A) (1) a phenyl group and an alkyl having 1 to 3 carbon atoms] Dialkoxysilane having one or two of the groups and having an alkoxy group having 1 to 4 carbon atoms, (2) phenyltrialkoxysilane or methyltrialkoxysilane having an alkoxy group having 1 to 4 carbon atoms, (3) an inorganic acid which does not contain a metal and contains at least one kind of chlorine atom and phosphorus atom or an organic acid having a PKa value of 0.8 to 6, and (4) water or water and an aliphatic monohydric alcohol Except water soluble Including under heating a mixture of solvent comprising an organic solvent, silicone oligomer of intrinsic viscosity of 0.1 to 10 ³ / g at 25 ° C. which is E dehydration condensation, monohydric alcohols or it aliphatic (B) Excluding mixed solvents and (C) condensation catalysts containing metal atoms].   The coating liquid for oxide film formation whose boiling point of the solvent of Claim 1 or 2 is 30 degreeC or more higher than the boiling point of the monohydric alcohol produced | generated by hydrolysis.   A method for producing an oxide film, wherein the coating liquid according to claim 1 or 2 is applied onto a substrate surface, dried at 50 to 200 ° C, and then fired at 300 to 1000 ° C.   An application film according to claim 1 or 2 is applied on a surface of a semiconductor element, dried at 50 to 200 ° C, and then fired at 300 to 1000 ° C to form an oxide film. Manufacturing method.