JPH09125006A - Polysilazane coating liquid and formation of ceramic coating layer using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polysilazane coating solution which can inhibit the liberation of toxic gas during its storage or application to the substrate and can flatten the global level difference, and the formation of ceramic coating layer using the same. SOLUTION: This polysilazane coating solution is prepared by dissolving a polysilazane resin comprising a recurring unit represented by the formula (R<1> , R<2> and R<3> are each H, a hydrocarbon group, a hydrocarbon-substituted silyl group or an amino group or carbyloxy group where at least one of R<1> to R<3> is hydrogen atom) in a mixed organic solvent which is composed of two different kinds of organic solvents, low and high-boiling ones where the difference in their boiling points is at least 30 deg.C and the content of the low-boiling solvent is at least 50wt.% based on the whole amount of the solvent. This coating solution is applied to the substrate, dried and fired to form the objective ceramic coating layer.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention can suppress the generation of toxic gas such as hydrogen gas and ammonia gas during storage and during coating on a substrate, and can flatten a global step. The present invention relates to a novel polysilazane-based coating liquid and a method for forming a ceramic coating on a substrate using the same.

[0002]

2. Description of the Related Art Conventionally, in the manufacture of semiconductor devices and display devices, smoothing / planarizing films, interlayer insulating films, protective films, multi-layer resist coatings, optical interlayer films such as phase shifters and refractive index adjusting coatings. Polysilazane-based material is often used as a film-forming material for the high-density, high-quality coating, and is excellent in crack resistance even when it is thickened. For this polysilazane-based material, various manufacturing methods can be used. And reforming methods have been proposed (JP-A-60-145903 and JP-A-61-28).
7930, JP-A-63-309526, JP-A-3-119077, and JP-A-3-232709.
Japanese Patent Laid-Open No. 5-238827, Japanese Patent Laid-Open No. 6-1
36130, JP-A-6-136131, JP-A-6-157764, JP-A-6-136323.
Japanese Patent Application Laid-Open No. 6-157989, Japanese Patent Application Laid-Open No. 6-2
40208, JP-A-6-299118, etc.).

By the way, in recent years, with the progress of large-scale integration of semiconductor elements and display devices, multi-layer wiring, large diameter and large size of substrates to be used, uniform coating film thickness and occurrence of striations occur. There has been a demand for improvement of coating properties such as prevention and improvement of flatness of a global step, and there has been a strong demand for development of a polysilazane-based coating solution suitable for this.

[0004]

The present invention meets the above-mentioned demands, has good coating characteristics, can flatten the global level difference, and can be used for hydrogen gas and ammonia gas during storage and during coating on a substrate. To provide a polysilazane-based coating liquid for forming a ceramic film, which can suppress the generation of such harmful gas, is easy to handle, and has excellent storage stability, and using this product, a ceramic film on a substrate. The purpose of the present invention is to provide a method for forming.

[0005]

As a result of various researches on a polysilazane-based coating liquid for forming a ceramic coating, the present inventors have identified two types of organic solvents having a boiling point difference of a specific value or more. Mixed organic solvent containing a ratio of, particularly each organic solvent is in a specific boiling range, solubility in water is small, and by using a mixed organic solvent containing no active hydrogen, polysilazane-based coating having excellent properties It was found that a liquid can be obtained, and the present invention has been completed based on this finding.

That is, the present invention provides a compound represented by the general formula

Embedded image (Wherein R ¹ , R ² and R ³ are each a hydrogen atom, a hydrocarbon group, a hydrocarbon-substituted silyl group, a hydrocarbon-substituted amino group or a carbyloxy group, and at least one of R ¹ , R ² and R ³ is Is a hydrogen atom), in a polysilazane-based coating solution comprising a solution of a polysilazane-based resin having a main skeleton composed of repeating units represented by
It consists of two kinds of low boiling point and high boiling point organic solvents, and the content of the low boiling point organic solvent is at least 50% by weight of the total amount of the solvent.
A polysilazane-based coating liquid for forming a ceramic coating, which is characterized by using a mixed organic solvent that is, and a coating of the polysilazane-based coating liquid for forming a ceramic coating on a substrate surface by a spinner, followed by drying and firing. The present invention provides a method for forming a ceramic coating.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The polysilazane-based coating liquid of the present invention is obtained by dissolving a polysilazane-based resin in an organic solvent, and the polysilazane-based resin has the general formula (I)

Embedded image Those having a main skeleton composed of a repeating unit represented by are used.

R ¹ , R ² and R ^{3 in the} general formula (I) are each a hydrogen atom, a hydrocarbon group, a hydrocarbon-substituted silyl group, a hydrocarbon-substituted amino group or a carbyloxy group. Here, as the hydrocarbon group, for example, an alkyl group,
Examples thereof include an alkenyl group, a cycloalkyl group, an aryl group and an aralkyl group. The hydrocarbon-substituted silyl group may be a silyl group having 1 to 3 of these hydrocarbon groups, preferably an alkylsilyl group, and the hydrocarbon-substituted amino group may be an amino group having 1 or 2 of the above hydrocarbon groups. Groups, preferably alkylamino groups. Examples of the carbyloxy group include an alkoxy group, an alkenyloxy group, a cycloalkoxy group, an aryloxy group and an aralkyloxy group. Also,
R ¹ , R ² and R ³ may be the same or different, but at least one of them is a hydrogen atom.

Such polysilazane resins are known (Japanese Patent Laid-Open Nos. 60-145903 and 6-06).
1-287930, JP-A-63-309526, JP-A-3-119077, JP-A-3-23.
No. 2709, No. 5-238827, No. 6-136130, No. 6-136131, No. 6-157764, No. 6-13.
6323, JP-A-6-15789, JP-A-6-240208, JP-A-6-299118, etc.), and in the present invention, the kind thereof is not particularly limited, and the above general formula ( R ¹ in I),
As R ² and R ³ , a hydrogen atom and one appropriately selected from the above groups (provided that at least one of R ¹ , R ² and R ³ is a hydrogen atom) can be used. Further, this polysilazane-based resin may be used alone,
Two or more kinds may be used in combination.

In the present invention, the organic solvent is composed of two kinds of low boiling point and high boiling point organic solvents having a boiling point difference of 30 ° C. or more, and the content of the low boiling point organic solvent is 50% by weight of the total amount of the solvent. It is necessary to use the above mixed organic solvent. By using such a mixed organic solvent,
Since the evaporation rate is appropriately controlled as compared with a single-type solvent, the global step can be efficiently flattened. If the boiling point difference is less than 30 ° C., the flatness of the global step is reduced. From the point of flatness of the global step,
The preferred boiling point difference is 50 ° C. or higher. On the other hand, when the content of the low boiling point organic solvent is less than 50% by weight of the total amount of the solvent, the drying property of the coating film is small and the fluidity of the coating liquid is large, so that it is difficult to form a thick film. Further, if the content of the low boiling point organic solvent is too large, the flatness of the global step is deteriorated. From the viewpoints of coating film drying property, thickening film, and flatness of global level difference, the mixing ratio of the high boiling point organic solvent and the low boiling point organic solvent is selected within the range of 1: 1 to 1: 5 by weight. Is preferred.

These organic solvents are not particularly limited as long as they can dissolve the polysilazane resin well.
Examples thereof include hydrocarbon solvents such as aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbon solvents, ether solvents such as aliphatic ethers and alicyclic ethers. , Hexane, heptane, isoheptane, octane, isooctane, nonane,
Aliphatic hydrocarbons such as 2,2,5-trimethylhexane and n-decane, cyclohexane, methylcyclohexane, dimethylcyclohexane, ethylcyclohexane,
Alicyclic hydrocarbons such as p-menthane, cyclohexene, dipentene and decalin, aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene, 1,1,2
-Halogenated hydrocarbons such as trichloroethane and tetrachloroethane, ether solvents such as dipropyl ether, butyl ethyl ether, dibutyl ether, dioxane and tetrahydropyran. Among these, a solvent having a water solubility of 0.1% by weight or less and containing no active hydrogen is preferable from the viewpoint of storage stability of the prepared coating liquid. The active hydrogen as used herein refers to a hydrogen atom directly bonded to oxygen or nitrogen in an organic compound. In general, a solvent containing an element such as O, N, S, or P in the molecule has high hydrophilicity (polarity) and is not preferable in terms of storage stability. As the solvent having a water solubility of 0.1% by weight or less and containing no active hydrogen, among the above-mentioned solvents,
Examples thereof include hydrocarbon solvents of aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, and halogenated hydrocarbon solvents.

On the other hand, if the boiling point is too low, it is likely to evaporate and the handling property and flammability at high temperature are deteriorated. On the other hand, if the boiling point is too high, the drying property is small and it is difficult to form a thick film.
Therefore, an organic solvent having a boiling point in the range of 80 to 200 ° C. is preferable, and further, from the viewpoint of safety for the human body,
Aliphatic and alicyclic hydrocarbons having low toxicity, especially carcinogenicity are preferable. Examples of the solvent satisfying such requirements include nonane, 2,2,5-trimethylhexane, n-decane, methylcyclohexane, dimethylcyclohexane, ethylcyclohexane, cyclohexene,
Examples thereof include dipentene, p-menthane, decalin and the like.

In the present invention, a mixed organic solvent of a low-boiling point organic solvent and a high-boiling point organic solvent is used, and the low-boiling point organic solvent and the high-boiling point solvent may be used alone or as a mixture of two or more kinds. May be A preferred example of the mixed organic solvent used in the present invention is at least one low boiling point solvent selected from cyclohexane, cyclohexene, methylcyclohexane, dimethylcyclohexane and 2,2,5-trimethylhexane, and p-menthane and ethyl. It is a mixture of at least one high boiling point solvent selected from cyclohexane, decalin and dipentene.

The coating liquid of the present invention is obtained by dissolving a polysilazane resin in the mixed organic solvent, and the concentration of the polysilazane resin depends on the average molecular weight, molecular weight distribution, structure, etc. of the polysilazane resin used. Different,
Usually, it is 50% by weight or less. If this concentration exceeds 50% by weight, the coating properties, storage stability, handleability, etc. will deteriorate. Further, if the concentration is too low, it becomes difficult to increase the film thickness. From the viewpoint of coating properties, storage stability, handleability, thickening of the film, etc., the preferable concentration of the polysilazane resin is 10 to 40.
It is in the range of wt%, and particularly preferably in the range of 20 to 30 wt%.

In the coating liquid of the present invention, the amount of the high boiling point solvent in the mixed organic solvent is preferably 0.5 to 4 parts by weight, more preferably 0.6 to 4 parts by weight with respect to 1 part by weight of the polysilazane resin. The range of 2 parts by weight is advantageous from the viewpoints of drying property, fluidity, and flatness of global step.

In order to form a ceramic coating according to the present invention, first, the above polysilazane-based coating solution is applied to the surface of a substrate by a spinner so that the ceramic coating formed in the final firing step has a desired thickness. To do. The base material used at this time is not particularly limited and is appropriately selected depending on the application of the ceramic coating formed. Examples of this base material include a silicon wafer. Then, the coating film is dried at a temperature of about 50 to 300 ° C., and then usually 300 to 800 ° C., preferably 3
By carrying out the firing treatment at a temperature of 50 to 600 ° C., a desired ceramic film can be obtained. The thickness of this coating is
Usually 0.01 to 3.0 μm, preferably 0.1 to 1.5
It is in the range of μm.

[0017]

EFFECT OF THE INVENTION The coating liquid for forming a ceramic coating of the present invention is excellent in coating properties, can flatten the global step, and suppresses the generation of harmful gases such as hydrogen gas and ammonia gas during storage and during coating. It is easy to handle and has excellent storage stability.

Further, a ceramic-based coating formed using this polysilazane-based coating liquid is, for example, a smoothing / planarizing film, an interlayer insulating film, a protective film, a multilayer resist coating in the production of semiconductor elements and display devices, It is useful as an optical interlayer film such as a phase shifter or a refractive index adjusting film.

[0019]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The global flatness and storage stability of the coating solution were evaluated by the methods described below.

(1) Global Flattening Property FIG. 1 is an explanatory view for evaluating the global flattening property. A ceramic film 3 is formed on a silicon wafer 1 provided with a pattern 2 having a step of 0.8 μm. Shows the state. Using FIG. 1, the global flatness was evaluated according to the following criteria. ◯: As shown in FIG. 1- (a), the surface of the formed coating film is hardly affected by the unevenness on the substrate surface and is flattened in a wide range. X: As shown in FIG. 1- (b), the surface of the formed coating film is affected by the unevenness on the substrate surface and is not flattened in a wide range.

(2) Storage stability The storage stability was evaluated according to the following criteria. ○: Put the coating solution in a glass container and completely seal it in the atmosphere,
Gas generation and precipitation of gelation product were not observed even after holding at 25 ° C for 10 days. ×: Put the coating solution in a glass container and completely seal it in the atmosphere,
Gas is generated and gelled product or precipitate is generated after holding at 25 ° C for 10 days.

Reference Example Production of Polysilazane Polysilazane was produced as follows based on the production method described in JP-A-3-232709. Temperature 0
After replacing the inside of the reactor installed in a constant temperature bath at ℃ with dry nitrogen, 980 ml of dry pyridine was added and kept until the temperature became constant, and then dichlorosilane (S
103.2 g of iH ₂ Cl ₂ ) was added to obtain a white solid adduct. Then, the reaction mixture was kept at 0 ° C., and 102.0 g of dry ammonia was blown thereinto while stirring.
After completion of the reaction, dry nitrogen was blown into the reaction mixture to remove unreacted ammonia, and then pressure filtration was performed under a nitrogen atmosphere to obtain a filtrate 17
00 ml were obtained.

Next, this filtrate was placed in a pressure resistant reactor, and a reforming reaction was carried out under a nitrogen atmosphere while stirring in a closed system at 90 ° C. for 3 hours. During this period, a large amount of gas was generated, and the pressure inside the container increased by 1.0 kg / cm ² before and after the reaction. After cooling to room temperature, dry ethylcyclohexane 34
Add 00 ml, and under reduced pressure of 3-5 mmHg, 50-70.
When the solvent was removed at 0 ° C, 79.56 g of a white solid inorganic polysilazane was obtained. The molecular weight of this product was measured by gel permeation chromatography (GPC method) to find that the number average molecular weight (Mn) was 1350.

Example 1 4.68 g of polysilazane obtained in Reference Example was added with 10.30 g of cyclohexane (bp = 80.72 ° C., water solubility = 0.01% by weight) and p-menthane (bp . = 16
9.5 ° C., water solubility = less than 0.1% by weight) 3.74 g
Was dissolved in a mixed solvent consisting of to prepare 18.72 g of 25 wt% polysilazane coating solution (A).

This coating solution was applied to 2000r on a 6-inch silicon wafer having a 0.8 μm step pattern.
spinner coating for 40 seconds at 80 ℃, 200 ℃,
When heat treatment was performed on a hot plate in the order of 300 ° C. for 3 minutes each, and then in a furnace (furnace) at 400 ° C. for 60 minutes in an air atmosphere, SiO ₂ with good global planarization was obtained. A ceramic coating was obtained.

When a coating film was formed on the bare wafer using the coating solution under the same coating conditions as above, the film thickness of the coating film was 5500Å. Further, when this coating solution was placed in a glass container, completely sealed in the atmosphere, and kept at 25 ° C. for 10 days, no gelation was observed.

Example 2 4.68 g of polysilazane obtained in Reference Example was added to 10.30 g of cyclohexene (bp = 82.97 ° C., water solubility = 0.03% by weight) and n-decane (bp). . = 174.
The mixture was dissolved in a mixed solvent consisting of 3.74 g of 12 ° C. and water solubility of less than 0.1% by weight) to prepare 18.72 g of 25% by weight polysilazane coating solution (B). Table 1 shows the solvent used, its weight ratio and the high boiling point solvent to resin ratio.

Next, using this coating solution, a ceramic film was formed in the same manner as in Example 1. Table 3 shows the results.

Example 3 4.68 g of polysilazane obtained in Reference Example was added to methylcyclohexane (bp = 100.93 ° C., solubility in water =
Less than 0.1% by weight) 11.04 g, dipentene (b.
p. = 177.7 ° C., water solubility = less than 0.1% by weight)
It was dissolved in a mixed solvent consisting of 3.0 g to prepare 18.72 g of 25 wt% polysilazane coating solution (C). Table 1 shows the solvent used, its weight ratio and the high boiling point solvent to resin ratio. Next, using this coating solution, a ceramic film was formed in the same manner as in Example 1. Table 3 shows the results.

Example 4 4.68 g of polysilazane obtained in Reference Example was added to 2,2,5-
11.7 g of trimethylhexane (bp = 124.08 ° C., water solubility = less than 0.1% by weight), decalin (bp = 195.82 ° C., water solubility = less than 0.1% by weight) ) 2.34 g of a mixed solvent was dissolved to prepare 18.72 g of 25 wt% polysilazane coating solution (D). Table 1 shows the solvent used, its weight ratio and the high boiling point solvent to resin ratio. Next, using this coating solution, a ceramic film was formed in the same manner as in Example 1. Table 3 shows the results.

Example 5 4.68 g of polysilazane obtained in Reference Example was mixed with 7.3 g of cyclohexane (bp = 80.72 ° C., water solubility = 0.01% by weight) and ethylcyclohexane (bp. = 1
31.8 ° C., water solubility = less than 0.1% by weight) 6.74
It was dissolved in a mixed solvent of 25 g to prepare 18.72 g of 25 wt% polysilazane coating solution (E). Table 1 shows the solvent used, its weight ratio and the high boiling point solvent to resin ratio. Next, using this coating solution, a ceramic film was formed in the same manner as in Example 1. Table 3 shows the results.

Example 6 4.68 g of polysilazane obtained in Reference Example was mixed with 10.29 g of cyclohexene (bp = 82.97 ° C., water solubility = 0.03% by weight) and decalin (bp =). 195.8
The mixture was dissolved in a mixed solvent consisting of 3.75 g of water (solubility of water = less than 0.1% by weight at 2 ° C.) to prepare 18.72 g of 25% by weight polysilazane coating solution (F). Table 1 shows the solvent used, its weight ratio and the high boiling point solvent to resin ratio. Next, using this coating solution, a ceramic film was formed in the same manner as in Example 1. Table 3 shows the results.

Example 7 4.68 g of the polysilazane obtained in the reference example was mixed with 10.29 g of o-dimethylcyclohexane (bp = 119.0 ° C, water solubility = less than 0.1% by weight) and dipentene (b ．
p. = 177.7 ° C., water solubility = less than 0.1% by weight)
It was dissolved in a mixed solvent consisting of 3.75 g to prepare 18.72 g of a 25 wt% polysilazane coating solution (G). Table 1 shows the solvent used, its weight ratio and the high boiling point solvent to resin ratio. Next, using this coating solution, a ceramic film was formed in the same manner as in Example 1. Table 3 shows the results.

Example 8 4.68 g of polysilazane obtained in Reference Example was added to methylcyclohexane (bp = 100.93 ° C., solubility in water =
Less than 0.1% by weight) 10.29 g, p-menthane (b.
p. = 169.5 ° C., water solubility = less than 0.1% by weight)
It was dissolved in a mixed solvent consisting of 3.75 g to prepare 18.72 g of 25 wt% polysilazane coating solution (H). Table 1 shows the solvent used, its weight ratio and the high boiling point solvent to resin ratio. Next, using this coating solution, a ceramic film was formed in the same manner as in Example 1. Table 3 shows the results.

Example 9 4.68 g of polysilazane obtained in Reference Example was added to 5.96 g of cyclohexane (bp = 80.72 ° C., water solubility = 0.01% by weight), ethylcyclohexane (bp. =
131.8 ° C., water solubility = less than 0.1% by weight) 4.9
It was dissolved in a mixed solvent of 6 g to prepare 15.60 g of a 30 wt% polysilazane coating solution (I). Table 1 shows the solvent used, its weight ratio and the high boiling point solvent to resin ratio.
Next, using this coating solution, a ceramic film was formed in the same manner as in Example 1. Table 3 shows the results.

Example 10 4.68 g of polysilazane obtained in the reference example was added to 17.94 g of cyclohexane (bp = 80.72 ° C., water solubility = 0.01% by weight) and ethylcyclohexane (bp.
= 131.8 ° C, water solubility = less than 0.1% by weight) 1
It was dissolved in a mixed solvent of 6.38 g to prepare 39.00 g of a 12 wt% polysilazane coating solution (J). Table 1 shows the solvent used, its weight ratio and the high boiling point solvent to resin ratio. Next, using this coating solution, a ceramic film was formed in the same manner as in Example 1. Table 3 shows the results.

Example 11 4.68 g of polysilazane obtained in Reference Example was added to 10.30 g of benzene (bp = 80.10 ° C., water solubility = 0.06% by weight) and o-xylene (bp). . = 144.
It was dissolved in a mixed solvent consisting of 3.74 g of 41 ° C. and water solubility = 0.03% by weight to prepare 18.72 g of 25% by weight polysilazane coating solution (K). Table 1 shows the solvent used, its weight ratio and the high boiling point solvent to resin ratio. Next, using this coating solution, a ceramic film was formed in the same manner as in Example 1. Table 3 shows the results.

Comparative Example 1 4.68 g of polysilazane obtained in Reference Example was dissolved in 14.04 g of o-xylene (bp = 144.41 ° C., solubility of water = 0.03% by weight) to obtain 25% by weight. % Polysilazane coating solution (O) was prepared. The solvents used are shown in Table 2. Next, using this coating solution, a ceramic film was formed in the same manner as in Example 1. Table 3 shows the results.

Comparative Example 2 4.68 g of polysilazane obtained in Reference Example was mixed with isopropyl ether (bp = 68.47 ° C., water solubility = 0.
55 wt%) was dissolved in 14.04 g to prepare a 25 wt% polysilazane coating solution (P). The solvents used are shown in Table 2. Next, using this coating solution, in the same manner as in Example 1,
A ceramic film was formed. Table 3 shows the results.

Comparative Example 3 4.68 g of polysilazane obtained in Reference Example was dissolved in 14.04 g of decalin (bp = 195.82 ° C., water solubility = less than 0.1% by weight) to obtain 25% by weight. A polysilazane coating solution (Q) was prepared. The solvents used are shown in Table 2. Next, using this coating solution, a ceramic film was formed in the same manner as in Example 1. Table 3 shows the results.

Comparative Example 4 4.68 g of polysilazane obtained in Reference Example was added to isopropyl ether (bp = 68.47 ° C., water solubility = 0.
55% by weight) 10.29 g, 1,1,1,2-tetrachloroethane (bp = 129.2 ° C., water solubility =
0.11 wt%) 3.75 g dissolved in a mixed solvent of 25 wt% polysilazane coating solution (R) 18.72 g
Was prepared. Next, using this coating solution, a ceramic film was formed in the same manner as in Example 1. Table 3 shows the results.

Comparative Example 5 4.68 g of the polysilazane obtained in the Reference Example was added to 3.74 g of cyclohexene (bp = 82.97 ° C., water solubility = 0.03% by weight), and n-decane (bp). . = 174.1
It was dissolved in a mixed solvent consisting of 10.30 g of 2 ° C. and water solubility = less than 0.1% by weight) to prepare 18.72 g of 25% by weight polysilazane coating solution (S). Table 2 shows the solvent used, its weight ratio and the high boiling point solvent to resin ratio. next,
Using this coating solution, a ceramic film was formed in the same manner as in Example 1. Table 3 shows the results.

Comparative Example 6 4.68 g of polysilazane obtained in the Reference Example was mixed with 10.29 g of toluene (bp = 110.63 ° C., water solubility = 0.05% by weight) and ethylbenzene (bp =). Thirteen
6.19 ° C., water solubility = 0.02% by weight) 3.75 g
Was dissolved in a mixed solvent consisting of to prepare a 25 wt% polysilazane coating solution (T). Next, using this coating solution, a ceramic film was formed in the same manner as in Example 1. Table 3 shows the results.

[0044]

[Table 1]

[0045]

[Table 2] (Note) 1) Solubility of water in organic solvent (at 20 to 30 ° C.) is shown by weight%. 2) In the mixed solvent system, the weight ratio of the low boiling point solvent and the high boiling point solvent is shown. 3) The weight ratio of the high boiling point solvent to polysilazane is shown.

[0046]

[Table 3]

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for evaluating the global flatness of a coating liquid.

[Explanation of reference symbols] 1 Silicon wafer 2 Step pattern 3 Ceramics film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshio Hagiwara 150 Nakamaruko, Nakahara-ku, Kawasaki-shi, Kanagawa Tokyo Ohka Kogyo Co., Ltd. No. Tonen Research Institute

Claims (6)

[Claims] 1. A compound of the general formula (Wherein R ¹ , R ² and R ³ are each a hydrogen atom, a hydrocarbon group, a hydrocarbon-substituted silyl group, a hydrocarbon-substituted amino group or a carbyloxy group, and at least one of R ¹ , R ² and R ³ is Is a hydrogen atom), in a polysilazane-based coating solution comprising a solution of a polysilazane-based resin having a main skeleton composed of repeating units represented by
It consists of two kinds of low boiling point and high boiling point organic solvents, and the content of the low boiling point organic solvent is at least 50% by weight of the total amount of the solvent.
A polysilazane-based coating liquid for forming a ceramic film, which comprises using the mixed organic solvent 2. The polysilazane-based coating liquid for forming a ceramic coating according to claim 1, wherein the low-boiling organic solvent or the high-boiling organic solvent, or both of them is a mixture of two or more organic solvents. 3. The polysilazane-based coating liquid for forming a ceramic coating according to claim 1, wherein each organic solvent has a boiling point of 80 to 200 ° C. 4. Each organic solvent has a solubility in water of 0.
The polysilazane-based coating liquid for forming a ceramic coating according to claim 1, 2 or 3, which is selected from those containing 1% by weight or less and containing no active hydrogen. 5. The polysilazane-based coating liquid for forming a ceramic coating according to claim 4, wherein each organic solvent is an aliphatic hydrocarbon or an alicyclic hydrocarbon. 6. A method for forming a ceramic coating, which comprises applying the polysilazane-based coating liquid for forming a ceramic coating according to claim 1 on the surface of a substrate with a spinner, followed by drying and firing.