JPH0714834B2 - Method for forming titania thin film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides a protective film, a dielectric film, an electric insulating film,
The present invention relates to a method for forming a titania thin film that acts as a high-refractive index film or the like.

[Prior Art] There are various methods for forming a titania thin film on a substrate. For example, Japanese Patent Application Laid-Open No. 59-26966 describes a so-called sol-gel method. This method comprises a step of preparing a sol having fine particles of titania as a dispersed phase and water as a dispersion medium, a step of adding a thermoplastic binder to the sol in the presence of water to prepare a mixture thereof, and a substrate. It includes a step of forming a thin film of the above mixture, a step of drying the thin film to gel the sol, and a step of firing the gelled thin film to convert it into a titania thin film. However, since this method uses sol as a so-called starting material, fine particles of titania tend to settle,
There is a problem that the obtained titania thin film is likely to be cracked or have uneven thickness.

[Problems to be Solved by the Invention] An object of the present invention is to solve the above-mentioned problems of the conventional method and to provide a method for obtaining a uniform titania thin film with few cracks and uneven thickness.

[Means for Solving the Problems] In order to achieve the above-mentioned object, in the present invention, (a) one kind of titanium alkoxide selected from the following group A and one kind selected from the following group B: And a step of preparing a mixture containing at least one solvent selected from the following Group C: Group A: titanium methoxide titanium ethoxide titanium ethoxide titanium propoxide titanium butoxide Group B: monoethanolamine diethanolamine Triethanolamine Group C: methanol ethanol propanol butanol (b) a step of forming a thin film of the above mixture on a substrate, (c) a step of drying and gelling the above thin film, and (d) baking the gelled thin film And a method of forming a titania thin film, which comprises:

Hereinafter, the present invention will be described in more detail for each step.

Preparation Step of Mixture: In the present invention, first, one titanium alkoxide selected from the following group A and 1 selected from the following group B are used.
A mixture of one hydrolysis inhibitor and one solvent selected from Group C below is prepared. The hydrolysis inhibitor prevents the precipitation of fine particulate hydroxides of titania due to hydrolysis in each step up to firing.
Although it is possible to select and use two or more kinds from each of the A, B, and C groups, there is almost no difference in the titania thin film obtained in this way, and the disadvantage of cost increase is even greater.

Group A: Titanium methoxide Titanium ethoxide Titanium propoxide Titanium butoxide Group B: monoethanolamine diethanolamine triethanolamine Group C: methanol ethanol propanol butanol The propoxide of group A above is either 1-propoxide or 2-propoxide. May be The butoxide may be any of 1-butoxide, 2-butoxide, isobutoxide and t-butoxide.

In addition, the propanol of group C is 1-propanol,
It may be any of 2-propanol. The butanol may be 1-butanol, 2-butanol, isobutanol or t-butanol.

The mixing ratio of the titanium alkoxide, the hydrolysis inhibitor and the solvent is slightly different depending on the kind thereof, but when the titanium alkoxide is mmol, the hydrolysis inhibitor is nmol and the solvent is p liter, the formula: 0.1 ≦ n / m ≦ 10 0.01 ≦ m / p ≦ 1 is preferably selected. When n / m <0.1, hydrolysis may not be sufficiently suppressed. Also,
When n / m> 10, the viscosity of the mixture becomes high, which may make the handling difficult. Furthermore, when m / p <0.01, too much solvent is not practical. Furthermore, when m / p> 1, the titanium alkoxide may remain undissolved. The preferable range is 0.5≤n / m≤3 0.05≤m / p≤0.5.

In the mixing operation, the titanium alkoxide of group A, the hydrolysis inhibitor of group B, and the solvent of group C may be mixed simultaneously, or a mixture of the hydrolysis inhibitor of group B and the solvent of group C may be mixed. The titanium alkoxide of Group A may be added to and mixed with. At this time, it is preferable that the titanium alkoxide of the group A is not exposed to moisture as much as possible until the mixing operation is completed, and it is preferable that the titanium alkoxide of the group A is replaced with dry nitrogen or the like in a glove box. However,
Subsequent operations can be performed in the atmosphere. In addition, B
It is preferable that the hydrolysis inhibitor of the group and the solvent of the group C are dehydrated in advance with molecular sieves or the like.

The obtained mixture is transparent or almost transparent, and exhibits orange, yellow, or the like depending on the type and amount of impurities contained in the titanium alkoxide of Group A.

Thin Film Forming Process of Mixture: In the present invention, next, a thin film of the above mixture is formed on the heat resistant substrate.

The substrate may be one that can withstand the firing temperature described below,
Materials include metals such as nickel, cobalt, chromium, and titanium, or alloys containing these metals as main components, carbon,
Inorganic substances such as silicon, ceramics such as alumina, silica, zirconia, titania, boron nitride, silicon nitride, silicon carbide and boron carbide, and glass may be used.
The shape may be any of fibrous shape, film shape, plate shape, bulk shape and the like. The surface of each of these substrates may be washed to remove oil or the like, or may be ground to smooth the surface.

The thin film can be formed by coating with a brush, a roller or the like, coating with a spray, or dip coating in which the substrate is dipped in the mixture and pulled up. Among them, the dip coating method is most preferable.

The thin film formed on the substrate wets when touched and flows when the substrate is tilted.

Drying and gelling step: In the present invention, next, the thin film of the mixture formed on the substrate is dried to scatter the solvent of group C to form the titanium alkoxide of group A and the hydrolysis inhibitor of group B. Use a gelled thin film.

This step may be performed at room temperature, or may be performed at a constant temperature of about 50 to 80 ° C. Further, it may be carried out in a glove box whose humidity is controlled to 1% or less. The gelled thin film does not flow even if the substrate is tilted, but it gives a fingerprint when pressed with a finger. Often slightly yellowish.

Firing step: In the present invention, the gelled thin film is then fired together with the substrate to convert it into a titania thin film. This firing is performed as follows, for example.

That is, the gelled thin film together with the substrate is put in a furnace and
Minutes, preferably 5 to 8 ° C / min, 400 to 1500 ° C, preferably 600 to 800 ° C, and held at that temperature for several tens of minutes to several hours, then 1 to 10 ° C / min, preferably Is 5-8 ° C
By cooling to room temperature at a rate of / min. If the rate of temperature increase or decrease is too high, the resulting titania thin film may be cracked. The firing temperature is
The temperature at which the gelled film transforms into a titania film, which is 400-1500 ° C, preferably 600-800 ° C, as described above.

Next, the present invention will be described in more detail based on examples.

Example 1 0.01 mol of titanium methoxide, 0.01 mol of monoethanolamine, and 0.1 liter of methanol were mixed for 1 hour in a glove box flowing dry nitrogen with a stirrer to prepare a mixture. .

On the other hand, a quartz glass plate having a length of 40 mm, a width of 10 mm and a thickness of 0.5 mm was ultrasonically cleaned with trichlene, acetone, ethanol and pure water for 3 minutes each, and finally dried by blowing high purity dry nitrogen. .

Next, the quartz glass plate was immersed in the mixture, and after 1 minute, it was vertically pulled up at a rate of 10 cm / min to form a thin film of the mixture on the quartz glass plate.

Next, the above thin film was dried in a constant temperature oven at 50 ° C. for 1 hour to gel.

Next, the gelled thin film together with the quartz glass plate was placed in an electric furnace, and
After raising the temperature to 700 ° C at a rate of ° C / min, holding it at that temperature for 1 hour, and then lowering it to room temperature at a rate of 6 ° C / min, a transparent, slightly grayish titania thin film was formed on the quartz glass. Obtained.

When the obtained titania thin film was observed with an optical microscope at 600 times, no cracks or the like were observed.
Further, when analyzed by X-ray diffractometry, a titania peak was observed at a position of 2θ = 25 °, and it was confirmed that the titania had been converted to titania.

Example 2 A titania thin film was obtained in the same manner as in Example 1 except that titanium ethoxide was used instead of titanium methoxide.

This titania thin film is also the same as that obtained in Example 1.
It was extremely homogeneous.

Example 3 A titania thin film was obtained in exactly the same manner as in Example 1 except that titanium 2-propoxide was used instead of titanium methoxide.

This titania thin film is also the same as that obtained in Example 1.
It was extremely homogeneous.

Example 4 A titania thin film was obtained in exactly the same manner as in Example 1 except that titanium 1-butoxide was used instead of titanium methoxide.

This titania thin film is also the same as that obtained in Example 1.
It was extremely homogeneous.

Example 5 0.01 mol of titanium methoxide, 0.01 mol of diethanolamine, and 0.1 liter of methanol were mixed with a stirrer for 1 hour in a glove box flowing dry nitrogen to prepare a mixture.

On the other hand, a quartz glass plate having a length of 40 mm, a width of 10 mm and a thickness of 0.5 mm was ultrasonically cleaned with trichlene, acetone, ethanol and pure water for 3 minutes each, and finally dried by blowing high purity dry nitrogen. .

Next, the quartz glass plate was immersed in the mixture, and after 1 minute, it was vertically pulled up at a rate of 10 cm / min to form a thin film of the mixture on the quartz glass plate.

Next, the above thin film was dried in a constant temperature oven at 50 ° C. for 1 hour to gel.

Next, the gelled thin film is placed in an electric furnace for each quartz glass plate,
The temperature was raised to 700 ° C at a rate of 6 ° C / min, held at that temperature for 1 hour, and then lowered to room temperature at a rate of 6 ° C / min, and a transparent, slightly grayish titania thin film was formed on the quartz glass. Got

When the obtained titania thin film was observed with an optical microscope at 600 times, no cracks or the like were observed.
Further, when analyzed by X-ray diffractometry, a titania peak was observed at a position of 2θ = 25 °, and it was confirmed that the titania had been converted to titania.

Example 6 A titania thin film was obtained in exactly the same manner as in Example 5 except that titanium ethoxide was used instead of titanium methoxide.

This titania thin film is also the same as that obtained in Example 5.
It was extremely homogeneous.

Example 7 A titania thin film was obtained in the same manner as in Example 5 except that titanium 2-propoxide was used instead of titanium methoxide.

This titania thin film is also the same as that obtained in Example 5.
It was extremely homogeneous.

Example 8 A titania thin film was obtained in the same manner as in Example 5 except that titanium 1-butoxide was used instead of titanium methoxide.

This titania thin film is also the same as that obtained in Example 5.
It was extremely homogeneous.

Example 9 Using a stirrer, 0.01 mol of titanium methoxide, 0.01 mol of triethanolamine, and 0.1 liter of methanol were mixed for 1 hour in a glove box flowing dry nitrogen to prepare a mixture. .

On the other hand, a quartz glass plate having a length of 40 mm, a width of 10 mm and a thickness of 0.5 mm was ultrasonically cleaned with trichlene, acetone, ethanol and pure water for 3 minutes each, and finally dried by blowing high purity dry nitrogen. .

Next, the quartz glass plate was immersed in the mixture, and after 1 minute, it was vertically pulled up at a rate of 10 cm / min to form a thin film of the mixture on the quartz glass plate.

Next, the above thin film was dried in a constant temperature oven at 50 ° C. for 1 hour to gel.

Next, the gelled thin film together with the quartz glass plate was placed in an electric furnace, and
The temperature was raised to 700 ° C at a rate of ℃ / min, held at that temperature for 1 hour, and then lowered to room temperature at a rate of 6 ° C / min, and a transparent, slightly grayish titania thin film was formed on the quartz glass plate. Got

When the obtained titania thin film was observed with an optical microscope at 600 times, no cracks or the like were observed.
Further, when analyzed by X-ray diffractometry, a titania peak was observed at a position of 2θ = 25 °, and it was confirmed that the titania had been converted to titania.

Example 10 A titania thin film was obtained in exactly the same manner as in Example 9 except that titanium ethoxide was used instead of titanium methoxide.

This titania thin film is also the same as that obtained in Example 9.
It was extremely homogeneous.

Example 11 A titania thin film was obtained in the same manner as in Example 9 except that titanium 2-propoxide was used instead of titanium methoxide.

This titania thin film is also the same as that obtained in Example 9.
It was extremely homogeneous.

Example 12 A titania thin film was obtained in exactly the same manner as in Example 9 except that titanium 1-butoxide was used instead of titanium methoxide.

This titania thin film is also the same as that obtained in Example 9.
It was extremely homogeneous.

Example 13 Using a stirrer, 0.01 mol of titanium methoxide, 0.01 mol of monoethanolamine, and 0.1 liter of ethanol were mixed for 1 hour in a glove box flowing dry nitrogen to prepare a mixture. .

On the other hand, a quartz glass plate having a length of 40 mm, a width of 10 mm and a thickness of 0.5 mm was ultrasonically cleaned with trichlene, acetone, ethanol and pure water for 3 minutes each, and finally dried by blowing high purity dry nitrogen. .

Next, a quartz glass plate was immersed in the above mixture, and after 1 minute, it was vertically pulled up at a rate of 10 cm / min to form a thin film of the mixture on the quartz glass plate.

Next, the above thin film was dried in a constant temperature oven at 50 ° C. for 1 hour to gel.

Next, the gelled thin film together with the quartz glass plate was placed in an electric furnace, and
After raising the temperature to 700 ° C at a rate of ° C / min, holding it at that temperature for 1 hour, and then lowering it to room temperature at a rate of 6 ° C / min, a transparent, slightly grayish titania thin film was formed on the quartz glass. Obtained.

When the obtained titania thin film was observed with an optical microscope at 600 times, no cracks or the like were observed.
Further, when analyzed by X-ray diffractometry, a titania peak was observed at a position of 2θ = 25 °, and it was confirmed that the titania had been converted to titania.

Example 14 A titania thin film was obtained in exactly the same manner as in Example 13 except that titanium ethoxide was used instead of titanium methoxide.

This titania thin film also, similar to that obtained in Example 13,
It was extremely homogeneous.

Example 15 A titania thin film was obtained in the same manner as in Example 13 except that titanium 2-propoxide was used instead of titanium methoxide.

This titania thin film also, similar to that obtained in Example 13,
It was extremely homogeneous.

Example 16 A titania thin film was obtained in exactly the same manner as in Example 13 except that titanium 1-butoxide was used instead of titanium methoxide.

This titania thin film also, similar to that obtained in Example 13,
It was extremely homogeneous.

Example 17 Using a stirrer, 0.01 mol of titanium methoxide, 0.01 mol of diethanolamine, and 0.1 liter of ethanol were mixed for 1 hour in a glove box flowing dry nitrogen to prepare a mixture.

On the other hand, a quartz glass plate having a length of 40 mm, a width of 10 mm and a thickness of 0.5 mm was ultrasonically cleaned with trichlene, acetone, ethanol and pure water for 3 minutes each, and finally dried by blowing high purity dry nitrogen. .

Next, a quartz glass plate was immersed in the above mixture, and after 1 minute, it was vertically pulled up at a rate of 10 cm / min to form a thin film of the mixture on the quartz glass plate.

Next, the above thin film was dried in a constant temperature oven at 50 ° C. for 1 hour to gel.

Next, the gelled thin film is placed in an electric furnace for each quartz glass plate,
The temperature was raised to 700 ° C at a rate of 6 ° C / min, held at that temperature for 1 hour, then lowered to room temperature at a rate of 6 ° C / min, and a transparent, slightly grayish titania was formed on the quartz glass plate. A thin film was obtained.

When the obtained titania thin film was observed with an optical microscope at 600 times, no cracks or the like were observed.
Further, when analyzed by X-ray diffractometry, a titania peak was observed at a position of 2θ = 25 °, and it was confirmed that the titania had been converted to titania.

Example 18 A titania thin film was obtained in exactly the same manner as in Example 17, except that titanium ethoxide was used instead of titanium methoxide.

Also this titania thin film, similar to that obtained in Example 17,
It was extremely homogeneous.

Example 19 A titania thin film was obtained in exactly the same manner as in Example 17, except that titanium 2-propoxide was used instead of titanium methoxide.

Also this titania thin film, similar to that obtained in Example 17,
It was extremely homogeneous.

Example 20 A titania thin film was obtained in exactly the same manner as in Example 17, except that titanium 1-butoxide was used instead of titanium methoxide.

Also this titania thin film, similar to that obtained in Example 17,
It was extremely homogeneous.

Example 21 Using a stirrer, 0.01 mol of titanium methoxide, 0.01 mol of triethanolamine, and 0.1 liter of ethanol were mixed for 1 hour in a glove box flowing dry nitrogen to prepare a mixture. .

On the other hand, a quartz glass plate having a length of 40 mm, a width of 10 mm and a thickness of 0.5 mm was ultrasonically cleaned with trichlene, acetone, ethanol and pure water for 3 minutes each, and finally dried by blowing high purity dry nitrogen. .

Next, the quartz glass plate was immersed in the mixture, and after 1 minute, it was vertically pulled up at a rate of 10 cm / min to form a thin film of the mixture on the quartz glass plate.

Next, the above thin film was dried in a constant temperature oven at 50 ° C. for 1 hour to gel.

Next, the gelled thin film together with the quartz glass plate was placed in an electric furnace, and
The temperature was raised to 700 ° C at a rate of ℃ / min, held at that temperature for 1 hour, and then lowered to room temperature at a rate of 6 ° C / min, and a transparent, slightly grayish titania thin film was formed on the quartz glass plate. Got

When the obtained titania thin film was observed with an optical microscope at 600 times, no cracks or the like were observed.
Further, when analyzed by X-ray diffractometry, a titania peak was observed at a position of 2θ = 25 °, and it was confirmed that the titania had been converted to titania.

Example 22 A titania thin film was obtained in exactly the same manner as in Example 21 except that titanium ethoxide was used instead of titanium methoxide.

This titania thin film also, similar to that obtained in Example 21,
It was extremely homogeneous.

Example 23 A titania thin film was obtained in exactly the same manner as in Example 21 except that titanium 2-propoxide was used instead of titanium methoxide.

This titania thin film also, similar to that obtained in Example 21,
It was extremely homogeneous.

Example 24 A titania thin film was obtained in exactly the same manner as in Example 21 except that titanium 1-butoxide was used instead of titanium methoxide.

This titania thin film also, similar to that obtained in Example 21,
It was extremely homogeneous.

Example 25 Using a stirrer, 0.01 mol of titanium methoxide, 0.01 mol of monoethanolamine and 0.1 liter of 2-propanol were mixed for 1 hour in a glove box flushing with dry nitrogen, and the mixture was stirred. Prepared.

On the other hand, a quartz glass plate having a length of 40 mm, a width of 10 mm and a thickness of 0.5 mm was ultrasonically cleaned with trichlene, acetone, ethanol and pure water for 3 minutes each, and finally dried by blowing high purity dry nitrogen. .

Next, the quartz glass plate was immersed in the mixture, and after 1 minute, it was vertically pulled up at a rate of 10 cm / min to form a thin film of the mixture on the quartz glass plate.

Next, the above thin film was dried in a constant temperature oven at 50 ° C. for 1 hour to gel.

Next, the gelled thin film together with the quartz glass plate was placed in an electric furnace, and
The temperature was raised to 700 ° C at a rate of ℃ / min, held at that temperature for 1 hour, and then lowered to room temperature at a rate of 6 ° C / min. Got

When the obtained titania thin film was observed with an optical microscope at 600 times, no cracks or the like were observed.
Further, when analyzed by X-ray diffractometry, a titania peak was observed at a position of 2θ = 25 °, and it was confirmed that the titania had been converted to titania.

Example 26 A titania thin film was obtained in exactly the same manner as in Example 25 except that titanium ethoxide was used instead of titanium methoxide.

This titania thin film is also similar to that obtained in Example 25.
It was extremely homogeneous.

Example 27 A titania thin film was obtained in exactly the same manner as in Example 25 except that titanium 2-propoxide was used instead of titanium methoxide.

This titania thin film is also similar to that obtained in Example 25.
It was extremely homogeneous.

Example 28 A titania thin film was obtained in the same manner as in Example 25 except that titanium 1-butoxide was used instead of titanium methoxide.

This titania thin film is also similar to that obtained in Example 25.
It was extremely homogeneous.

Example 29 A mixture was prepared by mixing 0.01 mol of titanium methoxide, 0.01 mol of diethanolamine, and 0.1 liter of 2-propanol for 1 hour using a stirrer in a glove box flushing with dry nitrogen. .

On the other hand, a quartz glass plate having a length of 40 mm, a width of 10 mm, and a thickness of 0.5 mm was ultrasonically cleaned for 3 minutes each using trichlene, acetone, ethanol, and pure water, and finally dried by spraying high-purity dry nitrogen. .

Next, the quartz glass plate was immersed in the mixture, and after 1 minute, it was vertically pulled up at a rate of 10 cm / min to form a thin film of the mixture on the quartz glass plate.

Next, the above thin film was dried in a constant temperature oven at 50 ° C. for 1 hour to gel.

Next, the gelled thin film is placed in an electric furnace for each quartz glass plate,
The temperature was raised to 700 ° C at a rate of 6 ° C / min, held at that temperature for 1 hour, and then lowered to room temperature at a rate of 6 ° C / min, and a transparent, slightly grayish titania thin film was formed on the quartz glass. Got

When the obtained titania thin film was observed with an optical microscope at 600 times, no cracks or the like were found.
Further, when analyzed by X-ray diffractometry, a titania peak was observed at a position of 2θ = 25 °, and it was confirmed that the titania had been converted to titania.

Example 30 A titania thin film was obtained in exactly the same manner as in Example 29 except that titanium ethoxide was used instead of titanium methoxide.

This titania thin film is also similar to that obtained in Example 29.
It was extremely homogeneous.

Example 31 A titania thin film was obtained in exactly the same manner as in Example 29 except that titanium 2-propoxide was used instead of titanium methoxide.

This titania thin film is also similar to that obtained in Example 29.
It was extremely homogeneous.

Example 32 A titania thin film was obtained in the same manner as in Example 29 except that titanium 1-butoxide was used instead of titanium methoxide.

This titania thin film is also similar to that obtained in Example 29.
It was extremely homogeneous.

Example 33 Using a stirrer, 0.01 mol of titanium methoxide, 0.01 mol of triethanolamine, and 0.1 liter of 2-propanol were mixed for 1 hour in a glove box flowing dry nitrogen, and the mixture was stirred. Prepared.

On the other hand, a quartz glass plate having a length of 40 mm, a width of 10 mm and a thickness of 0.5 mm was ultrasonically cleaned with trichlene, acetone, ethanol and pure water for 3 minutes each, and finally dried by blowing high purity dry nitrogen. .

Next, the quartz glass plate was immersed in the mixture, and after 1 minute, it was vertically pulled up at a rate of 10 cm / min to form a thin film of the mixture on the quartz glass plate.

Next, the above thin film was dried in a constant temperature oven at 50 ° C. for 1 hour to gel.

Next, the gelled thin film is placed in an electric furnace for each quartz glass plate,
The temperature was raised to 700 ° C at a rate of 6 ° C / min, held at that temperature for 1 hour, then lowered to room temperature at a rate of 6 ° C / min, and a transparent, slightly grayish titania was formed on the quartz glass plate. A thin film was obtained.

When the obtained titania thin film was observed with an optical microscope at 600 times, no cracks or the like were observed.
Further, when analyzed by X-ray diffractometry, a titania peak was observed at a position of 2θ = 25 °, and it was confirmed that the titania had been converted to titania.

Example 34 A titania thin film was obtained in exactly the same manner as in Example 33 except that titanium ethoxide was used instead of titanium methoxide.

This titania thin film is also the same as that obtained in Example 33.
It was extremely homogeneous.

Example 35 A titania thin film was obtained in exactly the same manner as in Example 33 except that titanium 2-propoxide was used instead of titanium methoxide.

This titania thin film is also the same as that obtained in Example 33.
It was extremely homogeneous.

Example 36 A titania thin film was obtained in exactly the same manner as in Example 33 except that titanium 1-butoxide was used instead of titanium methoxide.

This titania thin film is also the same as that obtained in Example 33.
It was extremely homogeneous.

Example 37 Using a stirrer, 0.01 mol of titanium methoxide, 0.01 mol of monoethanolamine, and 0.1 liter of 1-butanol were mixed for 1 hour in a glove box under a dry nitrogen flow, and the mixture was stirred. Prepared.

On the other hand, a quartz glass plate having a length of 40 mm, a width of 10 mm and a thickness of 0.5 mm was ultrasonically cleaned with trichlene, acetone, ethanol and pure water for 3 minutes each, and finally dried by blowing high purity dry nitrogen. .

Next, the quartz glass plate was immersed in the mixture, and after 1 minute, it was vertically pulled up at a rate of 10 cm / min to form a thin film of the mixture on the quartz glass plate.

Next, the above thin film was dried in a constant temperature oven at 50 ° C. for 1 hour to gel.

Next, the gelled thin film is placed in an electric furnace for each quartz glass plate,
The temperature was raised to 700 ° C at a rate of 6 ° C / min, held at that temperature for 1 hour, then lowered to room temperature at a rate of 6 ° C / min, and a transparent, slightly grayish titania was formed on the quartz glass plate. A thin film was obtained.

When the obtained titania thin film was observed with an optical microscope at 600 times, no cracks or the like were observed.
Further, when analyzed by X-ray diffractometry, a titania peak was observed at a position of 2θ = 25 °, and it was confirmed that the titania had been converted to titania.

Example 38 A titania thin film was obtained in the same manner as in Example 37 except that titanium ethoxide was used instead of titanium methoxide.

This titania thin film is also the same as that obtained in Example 37.
It was extremely homogeneous.

Example 39 A titania thin film was obtained in exactly the same manner as in Example 37 except that titanium 2-propoxide was used instead of titanium methoxide.

This titania thin film is also the same as that obtained in Example 37.
It was extremely homogeneous.

Example 40 A titania thin film was obtained in the same manner as in Example 37 except that titanium 1-butoxide was used instead of titanium methoxide.

This titania thin film is also the same as that obtained in Example 37.
It was extremely homogeneous.

Example 41 A mixture was prepared by mixing 0.01 mol of titanium methoxide, 0.01 mol of diethanolamine and 0.1 liter of 1-butanol for 1 hour using a stirrer in a glove box flowing dry nitrogen. .

On the other hand, a quartz glass plate having a length of 40 mm, a width of 10 mm and a thickness of 0.5 mm was ultrasonically cleaned with trichlene, acetone, ethanol and pure water for 3 minutes each, and finally dried by blowing high purity dry nitrogen. .

Next, the quartz glass plate was immersed in the mixture, and after 1 minute, it was vertically pulled up at a rate of 10 cm / min to form a thin film of the mixture on the quartz glass plate.

Next, the above thin film was dried in a constant temperature oven at 50 ° C. for 1 hour to gel.

Next, the gelled thin film together with the quartz glass plate was placed in an electric furnace, and
The temperature was raised to 700 ° C at a rate of ℃ / min, held at that temperature for 1 hour, and then lowered to room temperature at a rate of 6 ° C / min, and a transparent, slightly grayish titania thin film was formed on the quartz glass plate. Got

When the obtained titania thin film was observed with an optical microscope at 600 times, no cracks or the like were observed.
Further, when analyzed by X-ray diffractometry, a titania peak was observed at a position of 2θ = 25 °, and it was confirmed that the titania had been converted to titania.

Example 42 A titania thin film was obtained in exactly the same manner as in Example 41 except that titanium ethoxide was used instead of titanium methoxide.

This titania thin film is also the same as that obtained in Example 41.
It was extremely homogeneous.

Example 43 A titania thin film was obtained in exactly the same manner as in Example 41 except that titanium 2-propoxide was used instead of titanium methoxide.

This titania thin film is also the same as that obtained in Example 41.
It was extremely homogeneous.

Example 44 A titania thin film was obtained in exactly the same manner as in Example 41 except that titanium 1-butoxide was used instead of titanium methoxide.

This titania thin film is also the same as that obtained in Example 41.
It was extremely homogeneous.

Example 45 Using a stirrer, 0.01 mol of titanium methoxide, 0.01 mol of triethanolamine, and 0.1 liter of 1-butanol were mixed for 1 hour in a glove box flowing dry nitrogen, and the mixture was stirred. Prepared.

On the other hand, a quartz glass plate having a length of 40 mm, a width of 10 mm and a thickness of 0.5 mm was ultrasonically cleaned with trichlene, acetone, ethanol and pure water for 3 minutes each, and finally dried by blowing high purity dry nitrogen. .

Next, the quartz glass plate was immersed in the mixture, and after 1 minute, it was vertically pulled up at a rate of 10 cm / min to form a thin film of the mixture on the quartz glass plate.

Next, the above thin film was dried in a constant temperature oven at 50 ° C. for 1 hour to gel.

Next, the gelled thin film is placed in an electric furnace for each quartz glass plate,
The temperature was raised to 700 ° C at a rate of 6 ° C / min, held at that temperature for 1 hour, then lowered to room temperature at a rate of 6 ° C / min, and a transparent, slightly grayish titania was formed on the quartz glass plate. A thin film was obtained.

When the obtained titania thin film was observed with an optical microscope at 600 times, no cracks or the like were observed.
Further, when analyzed by X-ray diffractometry, a titania peak was observed at a position of 2θ = 25 °, and it was confirmed that the titania had been converted to titania.

Example 46 A titania thin film was obtained in exactly the same manner as in Example 45 except that titanium ethoxide was used instead of titanium methoxide.

This titania thin film was also prepared in the same manner as that obtained in Example 45.
It was extremely homogeneous.

Example 47 A titania thin film was obtained in exactly the same manner as in Example 45 except that titanium 2-propoxide was used instead of titanium methoxide.

This titania thin film was also prepared in the same manner as that obtained in Example 45.
It was extremely homogeneous.

Example 48 A titania thin film was obtained in the same manner as in Example 45 except that titanium 1-butoxide was used instead of titanium methoxide.

This titania thin film was also prepared in the same manner as that obtained in Example 45.
It was extremely homogeneous.

[Effects of the Invention] The present invention uses a mixture containing titanium alkoxide, a hydrolysis inhibitor, and a solvent, that is, a liquid as a starting material, and uses a sol as in the above-described conventional method as a starting material. In addition, it is possible to prevent the titanium alkoxide from being hydrolyzed by the use of a hydrolysis inhibitor, and to prevent precipitation of fine-grained hydroxides of titanium, etc. Difficult to form cracks and uneven thickness. Moreover, the characteristics of titania such as heat resistance, corrosion resistance, wear resistance, surface smoothness, electrical insulation, dielectric properties, and high optical refractive index are not impaired.

The method of the present invention has the above-mentioned features, for example, a titania thin film is formed for the purpose of imparting electric insulation or dielectric properties to an IC circuit, or a titania thin film is formed on an electrically insulating thin plate to form a multilayer capacitor. Or to form a titania thin film on an electrically insulating thin plate and stack it to use as a so-called surge absorber that absorbs a momentary large current such as a lightning strike, or as a titania thin film on various substrates. Can be used as a high-refractive index film in an optical waveguide, or a titania thin film can be formed on the surface of a lens, prism, or other optical component for the purpose of protecting it. it can.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuhiro Niwa 120 Asahigaoka, Meito-ku, Nagoya, Aichi Examiner Taizo Nakamura (56) References JP-A-58-167428 (JP, A) JP-A-55-141573 ( JP, A) JP 61-44949 (JP, B2)

Claims (1)

[Claims] (A) One titanium alkoxide selected from the following Group A, one hydrolysis inhibitor selected from the following Group B, and one solvent selected from the following Group C: And a group A: titanium methoxide titanium ethoxide titanium propoxide titanium butoxide group B: monoethanolamine diethanolamine triethanolamine group C: methanol ethanol propanol butanol (b) of the mixture on a substrate. A method of forming a titania thin film, comprising: a step of forming a thin film; (c) a step of drying and gelling the thin film; and (d) a step of firing the gelled thin film to convert it into a titania thin film.