JPH06166511A - Coating liquid for silicon oxide-based film formation - Google Patents

Abstract

PURPOSE:To provide a coating liquid capable of forming films causing no crack even in the case of being thick and excellent in adhesiveness, uniformity and electrical insulation, thus suitably usable for the formation of interlayer electrical insulating films, flattened films and protective films in semiconductor elements or liquid crystal display elements. CONSTITUTION:The objective coating liquid composed of (A) an organic solvent- contg. solution and (B) poly-silicon oxide obtained by forming an adduct by reaction between silicon tetrachloride or trichlorosilane and a base free from active hydrogen-bearing functional group followed by reaction of the adduct with water while suppressing gelation.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel coating liquid for forming a silicon oxide film, and more specifically to form a film which is free from cracks even in a thick film and which is excellent in adhesion, homogeneity and insulation. A coating liquid for forming a silicon oxide film, which is suitable for forming an interlayer insulating film, a flattening film, a protective film in a semiconductor device or a liquid crystal display device, or as a multilayer material for a multi-layer resist method and a phase shifter material. It is a thing.

[0002]

2. Description of the Related Art In the production of various electronic component materials, it is often necessary to form an interlayer insulating film, a flattening film, a protective film, etc. on a solid surface. As these films, a silicon oxide type coating film has been generally used conventionally, and is formed on a solid surface by a vapor phase growth method, a dispersion coating method, a film forming liquid coating method or the like.

However, the vapor phase growth method is a method for depositing and growing silicon oxide on a solid surface using a special apparatus, which requires an expensive apparatus and is difficult to mass-produce. Have Further, the dispersion coating method is a method of coating a solid compound with a silicon oxide powder or a glass powder dispersed in a polymer compound, and it has been attracting attention in recent years because it is simple, but it is a homogeneous dispersion. However, there are drawbacks such that the film thickness is not uniform, and pinholes are easily generated. Further, as a method for coating a film-forming solution, for example, it is known to use a reaction product obtained by reacting halogenosilane with a carboxylic acid and an alcohol as a coating solution (JP-B-52).
No. 16488 gazette), a silicon oxide-based coating formed from such a coating liquid has hygroscopicity, so that it absorbs moisture in the atmosphere to lower the adhesiveness and insulating properties, and a practical interlayer insulating film is formed. In addition to being unobtainable, there is a drawback in that a thick film tends to cause cracks.

Further, since the coating liquid of the reaction product of the halogenosilane has a relatively large molecular weight of the reaction product and a high viscosity, it has a fine pattern having a groove of 0.5 μm or less like the recent LSI. Is not suitable for forming an insulating film.

In order to overcome the drawbacks of the silicon oxide type coating,

[Chemical 4] A coating using an inorganic polysilazane based on the structural unit represented by the following formula has been proposed (JP-A-3-23270).
No. 9), this film is for forming silicon nitride fibers and cannot be applied as an interlayer insulating film because of its high dielectric constant.

[0006]

DISCLOSURE OF THE INVENTION The present invention overcomes the drawbacks of the prior art and forms a coating film which does not crack even in a thick film and which is excellent in adhesion, homogeneity and insulation. Therefore, the present invention has been made for the purpose of providing a coating liquid which is suitably used for forming an interlayer insulating film, a flattening film, a protective film and the like in a semiconductor device, a liquid crystal display device and the like.

[0007]

Means for Solving the Problems As a result of intensive studies to develop a coating solution having the above-mentioned preferable properties, the present inventors have obtained silicon tetrachloride or silane trichloride as a raw material and obtain it by a specific method. It has been found that the object can be achieved by the coating solution composed of the solution containing the polysilicon oxide and the organic solvent thus obtained, and the present invention has been completed based on this finding.

That is, according to the present invention, (A) silicon tetrachloride or silane trichloride or a mixture thereof is reacted with a base having no functional group having active hydrogen to form an adduct, and then the adduct is added. The present invention provides a coating liquid for forming a silicon oxide film, which comprises a solution containing poly (silicon oxide) obtained by reacting with water while suppressing gelation, and (B) an organic solvent.

The coating solution of the present invention comprises a solution containing (A) polysilicon oxide and (B) an organic solvent,
In the present invention, the component (A) component poly (silicon oxide) is produced as follows.

In general, silicon tetrachloride (SiCl ₄ ) and silane trichloride (HSiCl ₃ ) are highly reactive and react violently with moisture and oxygen in the air, and thus have a desired degree of polymerization and homogeneity. It is known to be difficult to give. Therefore, in the present invention, first, silicon tetrachloride or silane trichloride or a mixture thereof is reacted with a base having no functional group having active hydrogen to form an adduct, and then the adduct and water are gradually added. React.

Examples of the base having no functional group having active hydrogen include pyridine, pyridazine, pyrimidine, pyrazine, picoline, N-methylhyperidine, and tertiary amines such as trialkylamine. Considering that it is used as a scavenger of hydrogen chloride produced as a by-product in the subsequent reaction with water, the amount of these bases used is 2 to 10 chemical equivalent times that of silicon tetrachloride or silane trichloride used. It is desirable to select within the range.

To form the adduct, silicon tetrachloride or silane trichloride may be added dropwise to the base that is liquid at room temperature, or the base may be dissolved in a non-reactive, non-water-soluble solvent. Silicon tetrachloride or silane trichloride may be added dropwise to the solution. The reaction temperature at this time is -50 to 20.
The range of 0 ° C. is preferred, and the reaction is carried out in a dry inert gas atmosphere such as dry nitrogen or dry argon. In this case, the air in the reaction vessel may be replaced with the inert gas to carry out the reaction, or the reaction may be carried out while the inert gas is bubbled in the reaction solution.

The above-mentioned non-reactive and non-water-soluble solvent includes aliphatic hydrocarbons having a boiling point of 35 to 200 ° C. under normal pressure,
Aromatic hydrocarbons, ketones, ethers, etc. can be mentioned. You may use 1 type of these solvents,
You may use it in combination of 2 or more type.

Next, the adduct thus produced and water are reacted while suppressing gelation to produce poly silicon oxide. This gelation is suppressed by controlling the amount of water added and the temperature. This is, for example, by blowing water vapor together with an inert gas such as nitrogen or argon into a liquid base in which the adduct is suspended or into a mixed liquid containing the adduct and the base and a non-reactive, non-water-soluble solvent. It is advantageous to carry out the reaction while. At this time, a rapid heat is generated, so that the reaction temperature is -50 to 2 by sufficiently cooling.
It is desirable to keep the temperature in the range of 0 ° C., and the reaction is carried out under an atmosphere of an inert gas such as nitrogen or argon.

The poly-silicon oxide thus produced has the formula

[Chemical 5] The basic skeleton is the bond represented by

[Chemical 6] Or

[Chemical 7] And has a weight average molecular weight of 500 to
It is in the range of 3,000, is dissolved in a solvent, and salts formed from the reaction by hydrochloric acid and a base are removed by means such as filtration. When the solvent is volatilized from this solution, a viscous, colorless and transparent liquid is obtained, which is left at room temperature for a long time or baked in high temperature air to form a transparent solid film.

Further, for use as a coating solution, the above solution may be used as it is, but in order to remove an excess base, a large amount of a non-water-soluble solvent is added, and then the pressure is reduced or heated to effect the base. Volatilize. If the base is not completely removed in this process, the above operation is repeated.
Alternatively, the coating liquid may be prepared by adding a non-water-soluble solvent after performing a low temperature treatment in a reduced pressure atmosphere such as nitrogen or argon to obtain a viscous liquid.

In the coating liquid of the present invention, it is preferable that the organic solvent therein is a water-insoluble solvent having a boiling point of 90 to 200 ° C. under normal pressure. The coating solution of the present invention forms a silicon oxide type coating even when applied on a solid surface and left at room temperature for a long period of time, but the coating solution is applied on the solid surface and dried to form a coating film. Afterwards, 3 in the air
By firing in a temperature range of 50 ° C. or higher, a silicon oxide coating film having excellent physical properties is formed. Furthermore, by applying water vapor in this firing, SiO bond progresses, and a silicon oxide-based coating having more excellent physical properties is formed. The silicon oxide-based coating thus formed has no cracks even if it is a thick film, and is excellent in adhesion, homogeneity and insulation.

[0018]

EFFECT OF THE INVENTION The coating solution for forming a silicon oxide type coating of the present invention can form a silicon oxide type coating having excellent adhesion, homogeneity and insulation without cracking even in a thick film. It is preferably used as a layered material for forming an interlayer insulating film, a flattening film, a protective film in a device or a liquid crystal display device or for a multilayer resist method. Further, since the formed film has excellent homogeneity, light scattering is suppressed, and it is also useful as a phase shifter material formed on a mask for LSI.

[0019]

EXAMPLES Next, the present invention will be described in more detail by way of examples.

Example 1 Pyridine was added to a 400 ml five-necked flask equipped with a gas blowing tube, a thermometer, a stirrer, a separating funnel and a cooling condenser in a glow box in which air was previously replaced with dry nitrogen gas. Add 150 ml and stir while cooling with water, continue introducing dry nitrogen into pyridine through a gas blowing tube, and add about 30 g of a mixture of silicon tetrachloride and silane trichloride in a weight ratio of 1: 1 from a separating funnel to a reaction temperature It was added dropwise while cooling so as to be 5 to 20 ° C. At this time, when the temperature of the reaction is violently increased, the dropping speed is slowed down to adjust the reaction temperature within the above range.

By this reaction, a pyridine suspension in which a white precipitate floats was obtained. Next, the dry nitrogen, which had been introduced into the suspension through a gas blowing tube, was changed to nitrogen which was passed through water to contain steam, and the temperature of the suspension was adjusted to 5 to 2.
While maintaining the temperature at 0 ° C., bubbles were bubbled into the suspension little by little. In this case, if the temperature rises rapidly, the bubble of nitrogen is weakened or stopped to suppress the temperature rise, and the reaction temperature is adjusted within the above range.

When the amount of water bubbled with nitrogen decreased by 13 ml, the nitrogen was switched to dry nitrogen, and stirring was continued for another hour. Then, after removing the solid precipitate by filtration, 50 ml of m-xylene as a water-insoluble solvent was added to the filtrate, and the pressure was reduced to 20 Torr under reduced pressure.
Pyridine was removed at 5-30 ° C. This operation was repeated 4 times to obtain a coating liquid for forming a silicon oxide film having a solid content concentration of 10% by weight, in which pyridine was removed.

The coating solution obtained in this manner was applied to a depth of 1.
3 ml was dropped on a 6-inch silicon wafer having a groove of 0 μm and a width of 1.0 μm, and 2 times at 2000 rpm.
After spin coating for 0 seconds, it was dried at 140 ° C. for 30 minutes, and then baked at 400 ° C. for 60 minutes in a nitrogen atmosphere to form a silicon oxide based coating film on the silicon wafer. When this coating film was observed with a 200 × optical microscope and a 15000 × electron microscope, no cracks were observed on the surface, and it was a uniform flattened film with a flattening rate of 85%.

Example 2 A glass substrate (80 × 120) was used in the coating solution used in Example 1.
mm, thickness 1.1 mm), dip coat both surfaces of the glass substrate with the coating solution, dry at 140 ° C. for 30 minutes, and then bake at 500 ° C. for 60 minutes to form a film on the entire surface of the glass substrate. A 0.5 μm silicon oxide coating was formed.

The glass substrate thus obtained was washed with a 5 wt% hydrochloric acid aqueous solution for 5 minutes, then placed in a container containing a 10 wt% hydrochloric acid aqueous solution, immersed at 60 ° C. for 100 minutes, and exuded from the glass substrate. When a sodium leaching test was performed, the amount of sodium leached was 0.02 ppm. For comparison, a similar leaching test was conducted on a glass substrate on which a silicon oxide-based film was not formed. As a result, the amount of sodium leached was 0.32 ppm, confirming its effectiveness as a protective film for the glass substrate. It was

Claims (3)

[Claims] 1. (A) Silicon tetrachloride or trichlorosilane or a mixture thereof is reacted with a base having no active hydrogen-containing functional group to form an adduct, and then the adduct and water are gelled. A coating liquid for forming a silicon oxide coating film, which comprises a solution containing poly (silicon oxide) obtained by reacting while suppressing the formation of an organic solvent, and (B) an organic solvent. 2. Polysilicon oxide has the formula: The bond represented by is the basic skeleton, and the terminal is represented by the formula: Or Having a group represented by
The coating solution for forming a silicon oxide film according to claim 1, which is 00. 3. The organic solvent has a boiling point of 120 to 2 at atmospheric pressure.
The coating liquid for forming a silicon oxide film according to claim 1 or 2, which is a water-insoluble solvent at 00 ° C.