JPH03261629A - Process for forming film - Google Patents

Abstract

PURPOSE:To obtain a film having uniform thickness and excellent light- transmission, heat-resistance and chemical resistance and suitable as a protection film, optical wave-guide film, etc., by forming a film of a composition containing a hydrolysis and condensation product of a specific metal alkoxide or metal chloride and heat-treating the film. CONSTITUTION:A metal alkoxide (e.g. methyltrimethoxysilane) or a metal chloride (e.g. methyltrichlorosilane) expressed by formula (Y is organic group; M is tetravalent metal; X is chlorine or -OR; R is 1-4C alkyl) is prepared beforehand. A composition containing the hydrolysis and condensation product of the compound of formula or a mixture of the compound and other metal alkoxide (e.g. tetramethoxysilane) or metal chloride (e.g. tetrachlorosilane) is applied to a proper substrate and formed in the form of a film e.g. by drying in air. The film is heat-treated to obtain the objective film having uniform thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming a film applicable to various surface protection films, insulating films, optical waveguide films, and the like.

[Conventional technology]

Oxide films such as silica glass are superior to organic films such as polymers in terms of heat resistance, light transmittance, mechanical properties, etc., and are therefore used for various purposes. Conventionally, in order to form this type of oxide film, a method has generally been used in which a glass precursor is first synthesized by a sol-gel method and then this precursor is heated. Taking silica glass as an example,
First, as shown in the general formula (1) below, a metal alkoxide such as tetraethoxysilane is hydrolyzed and condensed to form a glass precursor, and then an alcoholic solution of the reaction solvent containing the glass precursor of the product is added to the After applying it to a substrate, etc., it was heated to obtain a glass film.

In addition to being used as mechanical, chemical, and electrical protective films, such glass films are used in various fields by utilizing their optical, electromagnetic, and catalytic properties.

S+-OR+ H2O→ -3i-0)1 +ROM(
1) [Problem to be solved by the invention] However, in the sol-gel method using metal alkoxide as a raw material, cracks tend to occur in the film due to the rigid chemical structure of the product, and generally a thin film of about 0.3 μm is formed. There was a problem that could only be solved. In addition, this kind of metal alkoxide hydrolysis/condensation product dissolves only in the reaction solvent, that is, once the solvent is removed from this reaction solution, it becomes difficult to dissolve in any solvent again, so it is generally used as a reaction solvent. Only alcoholic solvents such as ethyl alcohol and isopropyl alcohol could be used. This has the disadvantage that only alcohol-soluble additives can be used, such as when adding a third component to the resulting glass film. Furthermore, since this type of reaction solution contains water for hydrolyzing the metal alkoxide, condensation progresses between the silanol groups of the reaction product over time.
It had the disadvantage of poor storage stability.

The purpose of the present invention is to impart organic solvent solubility and flexibility to the oxide precursor by introducing an organic group into the precursor,
The object of the present invention is to provide a method for forming a film that has improved storage stability and facilitates the formation of composites and thick films.

[Means for Solving the Problems] To summarize the present invention, the present invention relates to a method for forming a film, which has the general formula Y-M-X, where Y is an organic group and M is a tetravalent Hydrolysis of metal alkoxides or metal chlorides alone or with other metal alkoxides or metal chlorides; - It is characterized by heating a film formed from a composition containing a condensation product.

In the present invention, since the precursor used at least partially has a ladder-like structure, it is characterized by a higher content of M-- bonds than ordinary chain-like organic polymers. When such a precursor film is heated, some or all of the organic groups are removed, resulting in a film having an oxide or a chemical structure similar to an oxide.

The organic group represented by Y in the metal alkoxide represented by the general formula Y-toX of the present invention is not particularly limited, and includes alkyl groups such as methyl, ethyl, propyl, butyl, alkenyl groups such as vinyl, etc. Aryl groups such as phenyl and precursors thereof are exemplified.

Also, in the general formula Y-M-X3, 4 represented by M
The valent metals include Si, Ge, Ti1Zr, S
n.

Examples include pb and the like. Among these, the most commonly used metals are Si, Ge, and Ti. Further, R represents an alkyl group such as methyl, ethyl, propyl or butyl.

Specific examples of substituted metal alkoxides include the following. Methyltrimethoxysilane, dithyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, hexyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, propyltriethoxysilane , butyltriethoxysilane, hexyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, 4-trimethoxysilyltetrahydrophthalic anhydride, 3,3.3
-) Lifluoropropyltrimethoxysilane, 3-(N
-Methylamino)propyltrimethoxysilane, 2-mercaptoethyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, 2-cyanoethyltriethoxysilane, allyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane Methoxysilane, 3
-aminopropyltriethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, methyltripropoxysilane, 3-[N-allyl-N(2-aminoethyl)]aminopropyltrimethoxysilane, 3-(N
-N-glycidyl)aminopropyltrimethoxysilane, 3-(N,N-diglycidyl)aminopropyltrimethoxysilane, methyltrimethoxygermane, ethyltrimethoxygermane, propyltrimethoxygermane, butyltrimethox sigelmane, hexyltrimethoxygermane Methoxygermane, vinyltrimethoxygermane, phenyltrimethoxygermane, methyltriethoxygermane, ethyltriethoxygermane, propyltriethoxygermane, butyltriethoxygermane, hexyltriethoxygermane, vinyltriethoxygermane, phenyltriethoxygermane, methyltriethoxygermane Methoxytitanium, dithyltrimethoxytitanium, propyltrimethoxytitanium, butyltrimethoxytitanium, hexyltrimethoxytitanium, vinyltrimethoxytitanium, phenyltrimethoxytitanium, methyltriethoxytitanium, ethyltriethoxytitanium, propyltriethoxytitanium, butyl triethoxytitanium, hexyltriethoxytitanium,
Vinyltriethoxytitanium, phenyltriethoxytitanium.

Examples of metal chlorides include n-butyl)IJ chlorosilane, dithyltrichlorosilane, methyltrichlorosilane, phenyltrichlorosilane, methyltrichlorogermane, and methyltrichlorotitanium.

In the present invention, the above substituted metal alkoxide or substituted metal chloride can be used as a raw material together with a commonly used metal alkoxide or metal chloride. Examples of this type of metal alkoxide that may be used in combination include the following. Tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane,
Tetraethoxyzircon, tetrabutoxyzircon, tetraisopropoxyzircon, tetramethoxygermane, tetraethoxygermane, tetrabutoxygermane,
Examples include tetraethoxytitanium, tetrabutoxytitanium, tetrabutoxytin, pentabutoxyniobium, pentabutoxytallium, triethoxyboron, tributoxygallium, dibutoxylead, tributoxyneodymium, and tributoxyerbium.

In addition, substituted alkoxides with two alkoxyl groups substituted, such as dimethyljethoxysilane, diphenyljethoxysilane, etc., may be used in combination with other compounds to increase the flexibility of the precursor or oxide film. Alternatively, it is also effective in some cases to use a substituted chloride in which two chlorine atoms are substituted, such as dimethyldichlorosilane and diphenyldichlorosilane.

Examples of other metal chlorides that may be used in combination include tetrachlorosilane, tetrachlorogermane, and tetrachlorotitanium.

An example of the forming method of the present invention is to apply the composition to a suitable substrate by spin cord or dip coating, air dry it, and then heat it. Although the heating temperature is not particularly limited, it is generally 200°C, and if a film having a structure closer to that of an oxide is desired, a temperature of 500°C or higher is desirable.

Further, in this case, it is appropriate to carry out the process in an atmosphere containing oxygen.

〔Example〕

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

Example 1 Polymethylsilsesquioxane, which is a hydrolysis/condensation product of methyltriethoxysilane, was dissolved in tetrahydrofuran to prepare a precursor solution.

This solution was applied to a substrate by dip coating and air-dried to form an organic film. Figure 1 shows the results of thermogravimetric analysis of this precursor in air (heating rate 20°C/min) in terms of the relationship between temperature (°C, horizontal axis) and weight residual rate (%, vertical axis). It is. Weight loss due to condensation at around 200°C is followed by weight loss due to elimination of organic groups from around 400°C. The weight loss rate at 600°C is about 20%,
At temperatures above this temperature, almost no weight change was observed.

Next, this precursor film was heated at a temperature of 400° C. to 900° C. for 3 hours each. A transparent and uniform film was formed at any temperature. Figure 2 shows the heat treatment temperature (°C, horizontal axis) and film thickness (
FIG. The film thickness is almost constant at around 700°C.

Figure 3 shows the infrared spectra of the precursor (Figure 3, A) and the film (Figure 3, B) heat-treated at 700°C at wavenumbers (c
FIG. 3 is a diagram showing the relationship between l' (horizontal axis) and transmittance (vertical axis). 1200c by heat treatment at 700℃
The absorption of S+-C84 near m-' and 780ca+-' almost disappears, and at 1100 cm-' and 800 cm-
' and 5i-0 absorption near 470 C[O-' is observed. Note that the absorption near 600 cm-' is caused by the substrate (S
i) Absorption.

Furthermore, it was observed that the films produced at any heat treatment temperature were completely insoluble in general-purpose organic solvents and had excellent chemical resistance.

Example 2 Phenylpolysilsesquioxane, which is a hydrolysis/condensation product of phenyltriethoxysilane, was dissolved in methyl isobutyl ketone (MIBK) to prepare a precursor solution. This solution was applied to a silicon substrate and a quartz glass substrate using a spin cord to form a precursor film with a thickness of about 2.5 μm.

Next, after air-drying these films, they were heated at 400°C to 90°C in an electric furnace.
Each sample was heat treated at a temperature of 00°C for 3 hours. A uniform, crank-free film was formed at any temperature.

FIG. 4 is a diagram showing the infrared spectrum of a film coated on a silicon substrate in terms of the relationship between wave number (C[11-', horizontal axis) and transmittance (vertical axis). In Figure 4, C1DSE, FS
G and H are heat treatment temperature 400.500.600 respectively
．． These are spectra of films produced at 700, 800 and 900°C.

This figure shows that organic matter (Siφ, 11
It can be seen that 30C[I+-') has begun to desorb.

Figure 5 shows the transmission characteristics before heat treatment (5'5!J, ■) and after heat treatment at 900°C (Figure 5, J) in wavelength (nm, horizontal axis).
FIG. 10 is a diagram showing the relationship between and transmittance (%, vertical axis).

In the spectrum after the heat treatment, no phenyl absorption observed in the 0.2 to 0.3 μm range was observed, indicating that the light transmittance was excellent in the wide wavelength range.

Example 3 A MIBK solution of phenylpolysilsesquioxane having a carboxyl group, which is a hydrolysis/condensation product of 0.8 mol of phenyltriethoxysilane and 0.2 mol of 4-trimethoxysilyltetrahydrophthalic anhydride, was used as a substrate. The corresponding membrane was obtained by casting.

Next, this precursor film was heated at 900° C. for 3 hours to obtain a transparent and uniform film.

Example 4 4-trimethoxysilyltetrahydrophthalic anhydride 0
．． An ethanol solution of a hydrolysis/condensation product of 3 mol and 0.7 mol of tetraethoxysilane was cast on a silicon substrate to obtain a corresponding organic film.

Next, this film was heated at 1200°C to obtain a transparent and uniform film.

Example 5 In Example 1, a hydrolysis/condensation product of methyltrichlorosilane was used instead of polymethylsilsesquioxane, a hydrolysis/condensation product of methyltrimethoxysilane, to obtain a transparent and uniform film. Ta.

Example 6 MI of hydrolysis/condensation product of 0.9 mol of methyltriethoxysilane and 0.1 mol of methyltributoxygermane
The corresponding film was obtained by casting the BK solution onto the substrate.

Example 7 MIB of hydrolysis/condensation product of 0.9 mol of methyltriethoxysilane and 0.1 mol of methyltributoxytitanium
The corresponding film was obtained by casting the K solution onto the substrate.

Next, this precursor film was heated at 1100° C. for 3 vf to obtain a transparent and uniform film.

〔Effect of the invention〕

As explained above, since the present invention uses a precursor soluble in an organic solvent, a uniform film having a thickness of 1 μIn or more is formed. Since this film has excellent light transmittance, heat resistance, and chemical resistance, it may be applicable to various protective films, light-transmitting films, and the like.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the results of thermogravimetric analysis in air of the precursor produced in Example 1, FIG. 2 is a diagram showing the relationship between heat treatment temperature and film thickness of the precursor produced in Example 1, Figure 3 shows the precursor film produced in Example 1 and its 7
Figure 4 showing the infrared spectrum of the film heat-treated at 00°C.
The figure shows infrared spectra of the precursor film produced in Example 2 and heat-treated at various temperatures, and FIG. 5 shows the transmission characteristics of the film produced in Example 2.

Claims (1)

[Claims] 1. Represented by the general formula Y-M-X_3 [wherein Y is an organic group, M is a tetravalent metal, and X is chlorine or an -OR group (R is an alkyl group having 1 to 4 carbon atoms]) A method for forming a film, comprising heating a film formed from a composition containing a metal alkoxide or metal chloride alone or a hydrolysis/condensation product with another metal alkoxide or metal chloride.