JPH0416505A - Production of silicon dioxide coating film - Google Patents

Abstract

PURPOSE:To uniformly form a silicon dioxide coating film on the surface of a substrate of an arbitrary shape at a low temp. by bringing the substrate into contact with an aq. soln. contg. ammonium silicofluoride. CONSTITUTION:A treating soln. is prepd. by adding boric acid, etc., to an aq. ammonium silicofluoride soln. A substrate is brought into contact with the treating soln. by immersion or other method and a silicon dioxide coating film is deposited on the surface of the substrate. By this method, a silicon dioxide coating film can be formed even on a substrate of a metal, etc., causing a reaction in a highly acidic bath. Since the aq. ammonium silicofluoride soln. is not highly acidic and treatment can be carried out at a relatively low temp., the danger of handling can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a silicon oxide film, and particularly to contacting a substrate with a treatment liquid containing ammonium fluorosilicate.

[Prior art] As a method for producing a silicon oxide film on the surface of an arbitrary base material,
Saturating silicon oxide in hydrosilicofluoric acid with a concentration of 0.5 to 3.0 mol/9, then adding 2.0xlO-2 mol or more of boric acid per 1 g of a saturated silicon oxide aqueous solution of hydrosilicic fluoric acid. A method of manufacturing a silicon oxide film on the surface of a substrate by immersing the substrate in a treatment solution supersaturated with silicon oxide
-196744), and a method in which a supersaturated state of silicon oxide is maintained to some extent by continuing to add boric acid to the treatment solution, and a silicon oxide film is repeatedly deposited (JP-A-5
8-161944), and in place of boric acid as an additive in the above method, an aluminum compound, a calcium compound,
Improved method using magnesium compounds, etc.
20876) etc. are known.

[Problems to be Solved by the Invention] The above precipitation method has advantages such as being able to form a film at low temperatures and forming a uniform silicon oxide film on the surface of a base material of any shape. The hydrosilicofluoric acid used is a strongly acidic liquid comparable to sulfuric acid. Therefore, there is a problem in that substrates such as metals that react in acidic aqueous solutions cannot be subjected to immersion treatment as they are. There was also the problem that since it was a strong acid, it was quite dangerous to handle.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and includes using an aqueous solution containing ammonium silicofluoride as a treatment liquid and bringing the substrate into contact with the treatment liquid. This is a method for producing a silicon dioxide film in which a silicon dioxide film is deposited on a surface.

Here, the aqueous solution used is an ammonium silicate fluoride solution or a solution in which silicon dioxide is dissolved in an ammonium silicate fluoride solution. As additives, boric acid, aluminum chloride, calcium chloride, and magnesium chloride are used, and for example, aluminum compounds, calcium compounds, magnesium compounds, etc. that react with fluorine can be effectively used. A method for forming a silicon oxide film on a substrate such as a glass plate or metal is generally to immerse the substrate in a treatment liquid, but it is also possible to apply the treatment liquid onto the substrate and bring it into contact with it. good. The silicon oxide film obtained by the present invention is probably deposited on the substrate as a result of a chemical reaction. Therefore, in general, the higher the concentration of silicon in the processing solution, the higher the film forming ability, and the higher the processing temperature, the larger the amount of film formed and the faster the film forming rate.

A treatment solution prepared by adding additives such as boric acid to an aqueous solution containing ammonium silicofluoride is maintained at a temperature of 20°C to 60°C, and a substrate such as glass is immersed in the solution and held for about 16 hours. A silicon dioxide film b is formed on the surface.

[Function] According to the present invention, the characteristics of the conventional method for producing a silicon dioxide film of this type are: (1) the film can be formed at a low temperature, and (2) a silicon oxide film can be uniformly formed on the surface of a base material of any shape. In addition to these advantages, silicon dioxide coatings can now be formed on substrates such as metals that react in strongly acidic solutions, which could not be applied in the past, expanding the range of application.

Further, the ammonium silicofluoride used is available as a powder reagent, and a highly pure processing solution can be easily prepared. When an aqueous ammonium fluorosilicate solution is used as a processing liquid, it can be used as a processing liquid and immediately perform a film forming process by simply dissolving the reagent powder. Processes such as saturating silicon dioxide are omitted, improving work efficiency. The ammonium fluorosilicate aqueous solution used in the present invention is not strongly acidic and can be processed at a relatively low concentration, so handling risks are considerably reduced.

[Example] Example 1 50 mf of ammonium fluorosilicate aqueous solution adjusted to various concentrations
f has a concentration of 0. 40 by adding 5 mol/Q boric acid aqueous solution.
Stir for 30 minutes in a constant temperature water bath at °C. After that, the soda lime glass (50℃m x 25mm) was thoroughly washed.
X1. ls 輯) was immersed. The glass substrate was partially masked with masking tape. After 16 hours, the glass substrate was taken out and the film thickness was measured using a contact needle type film thickness measuring device.

The treatment results are shown in Table-1. Note that the formed film was confirmed to be a silicon oxide film by infrared spectroscopy (!R), secondary ion mass spectrometry (SIMS), and the like.

Table 1 summarizes how the processing solution concentration and the amount of boric acid added affect the film formation rate. For example, when the processing solution concentration is 0.8 mol/9, the amount of boric acid added is 1 .5ml
! A 43 nm silicon oxide film was obtained on a glass substrate soaked for 16 hours, and a 55 nm film was obtained at 2.0 m1t. In addition, when the amount of boric acid added was 2.0 m51,
It is shown that a 90 nm film was obtained when treated at 0°C. Furthermore, when the amount of boric acid added increases to 4.0 mN, the amount of film formed becomes 0.

From this, there is a certain relationship between the amount of additives added and the amount of film formed, and the amount of additives added should not be too small.
I also learned that it is not good to have too much.

Table 1 shows that the relationship between the amount of additive added and the amount of film formed has a certain relationship with the concentration of the processing liquid. In other words, if the concentration of the processing solution is low, the film forming ability will not be exhibited unless the amount of additive added is increased. On the other hand, it can be seen that when the concentration of the processing solution becomes high, the film forming ability can be exhibited even by adding a small amount of additive.

Example 2 100 m9 of an approximately 0.4.0.6.0.8 mol/11 ammonium fluorosilicate aqueous solution saturated with silicon dioxide was placed in a beaker and maintained at 35° C. in a constant temperature water bath. Next 0.
2 m9 of a 5 mol/j boric acid aqueous solution was added. After addition,
After 30 minutes had elapsed, five thoroughly washed and dried soda lime glasses were immersed in each glass. Each soaked soda lime glass was taken out one by one at regular intervals and the amount of film formed was measured using a contact needle type film thickness measuring device. FIG. 1 shows the relationship between the immersion time and the amount of film formed. The horizontal axis shows the immersion time of the glass, and the vertical axis shows the amount of silicon oxide film formed. The amount of film formed increased monotonically over time.

Furthermore, the amount of film formed was larger with the treatment solution having a higher concentration of ammonium fluorosilicate.

Example 3 Using an ammonium fluorosilicate aqueous solution adjusted to 1 mol/11 as a treatment liquid, 50 mg was taken in a beaker and kept in a constant temperature water bath at 35°C. While keeping the processing solution at 35℃, add zero to the processing solution.
．． Add 2 m9 of 5 mol boric acid aqueous solution and stir for 30 minutes. After stirring, a glass substrate with an ITO film (indium tin oxide film) and a float glass plate were subjected to immersion treatment as a base material.

Since an ITO film dissolves in hydrosilicofluoric acid, a silicon oxide film cannot be formed using conventional methods. However, after 16 hours of carrying out the treatment in Example 3, the ITO film was taken out and its thickness was measured using a contact needle type film thickness measuring device. It was found that the ITO film was formed without dissolving, and the film thickness was 50 nm along with the float plate. It was covered with a silicon oxide film.

Further, a stainless steel plate was subjected to immersion treatment under the same treatment conditions. The surface of a stainless steel plate is eroded in hydrofluorosilicic acid and loses its gloss, but the method of Example 3 allows a silicon oxide film to be formed on the surface with a thickness of 50 rpm without losing the surface gloss. was completed.

Example 4 Ammonium fluorosilicate aqueous solution 1 adjusted to 0.8 mol/9
Pour 50ml of 50mN into each beaker and add 40mN to each beaker.
Keep in a constant temperature water bath. 0.02 mol of calcium chloride, 0.003 mol of aluminum chloride, and 0.02 mol of magnesium chloride were dissolved in a small amount of distilled water and added to each treatment solution. After stirring for 30 minutes, a thoroughly washed float plate measuring 50 mm x 25 mm x 1.1 mm was subjected to immersion treatment. Part of the glass was masked with masking tape. After immersing for 16 hours, the glass was taken out, washed, dried, and measured using a contact needle type film thickness measuring device. Films of 30 nm, 80 nm, and 30 nm were obtained, respectively.

[Effects of the Invention] According to the present invention, the characteristics of the conventional method for forming this type of silicon dioxide film are: 1. The film can be formed at a low temperature, and 2. A silicon oxide film can be formed uniformly on the surface of a base material of any shape. can. Furthermore, it is possible to form silicon dioxide coatings on substrates such as metals that react in strongly acidic solutions, which cannot be applied using the conventional methods, without losing any of the advantages described above, and it is expected that the scope of treatment will be greatly expanded.

The ammonium silicofluoride used is available as a powdered reagent, and a highly pure processing solution can be easily prepared.

When using an aqueous ammonium silicofluoride solution as a processing solution, it can be used as a processing solution and immediately perform film formation by simply dissolving the reagent powder, which improves work efficiency by eliminating steps such as saturating silicon dioxide. do.

The aqueous ammonium silicate fluoride solution used as the treatment liquid in the present invention is not strongly acidic and can be treated at a relatively low concentration, so it has remarkable effects such as considerably reducing handling risks. be.

[Brief explanation of drawings]

FIG. 1 shows the relationship between the immersion time and the amount of film formed when the treatment liquid of the present invention is used. Agent Patent Attorney Seiichi Ohno Procedural Amendment (Spontaneous) No. 11'2 Indication of the Case 1990 Patent Application No. 117044 2. Name of the Invention Manufacture of silicon dioxide coating Method 3: Relationship with the person making the amendment Patent applicant address: 3-5-11 Doshomachi, Chuo-ku, Osaka Name (40
0) Nippon Sheet Glass Co., Ltd. Representative Tatsu Nakajima 24, agent name (6908)

Claims (2)

[Claims] (1) A method for producing a silicon dioxide coating, which comprises bringing a substrate into contact with a treatment liquid consisting of an aqueous solution containing ammonium silicofluoride and an additive to form a silicon oxide coating on the surface of the substrate. (2) Claim 1, wherein the additive is boric acid, aluminum chloride, calcium chloride, or magnesium chloride.
A method for producing a silicon dioxide film as described in 1.