JP2001295055A - Thin film deposition method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin film deposition method by which a thin film having the excellent quality is deposited at a low temperature and an inexpensive thin film is deposited by a simple device. SOLUTION: A plurality of substrates 2 with a thin film forming material 1 applied thereto are arranged in a stepwise manner keeping a predetermined spacing therebetween, and heat-treated while irradiating a space 3 formed by two substrates 2 adjacent to each other with the ultraviolet ray 5 led via a waveguide means 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming a thin film. More specifically, the present invention relates to a thin film forming method capable of forming a good quality thin film at a low temperature and forming an inexpensive thin film with a simple apparatus.

[0002]

2. Description of the Related Art As a method of forming a thin film, a sputtering method, a vapor deposition method, a coating method and the like are known. Among these, a coating type thin film forming method such as a sol-gel method or a thermal decomposition method can form an inexpensive thin film with a simple apparatus, and thus a method for forming an insulating film, a dielectric film, a transparent conductive film, and the like. Widely used as. Also, the types of thin films that can be used have been widened, and utilization in a wide range of fields is expected by taking advantage of the characteristics.

However, in the conventional coating type thin film forming method, it is necessary to set the temperature of the decomposition of the thin film forming material and the formation of the thin film to a higher temperature than other methods such as a sputtering method and a vapor deposition method in order to obtain a high quality thin film. In some cases, this method is difficult to apply depending on the type of thin film, and this has been a cause of limiting the use of this method.

On the other hand, there has been disclosed a thin film forming method in which a substrate coated with a thin film forming material is heat-treated while being irradiated with ultraviolet rays.

According to this method, a high-quality thin film can be formed at a low temperature by the effect of ultraviolet irradiation (for example,
When the SiO ₂ thin film is formed by heat treatment while irradiating ultraviolet rays, a thin film having the same refractive index can be formed at a low temperature of about 200 ° C. as compared with the case where no ultraviolet rays are irradiated).
Further, an ITO thin film which is a transparent conductive film can also form a low-resistance thin film.

[0006]

However, conventionally, when a thin film is formed on a plurality of substrates by this method, it is necessary to irradiate ultraviolet rays to the surface of the substrate on which the thin film forming material has been applied, so that the plurality of substrates are exposed on one surface. Were irradiated with ultraviolet rays from above.

For this reason, there is a problem in that the space in the apparatus cannot be effectively used, the mass productivity is reduced as compared with the method of not irradiating ultraviolet rays, and the apparatus needs to be enlarged in order to improve the mass productivity. Was.

Further, in order to uniformly form a thin film on a large substrate or a plurality of substrates juxtaposed on one surface by this method, it is necessary to uniformly irradiate ultraviolet rays. A method of scanning at the top, a method of arranging a large number of rod-shaped ultraviolet lamps, and the like have been used.

For this reason, the former method requires a complicated apparatus, and the latter requires many ultraviolet lamps. As a result, the advantage that an inexpensive thin film can be formed by a simple apparatus using a coating method is reduced. There was a problem that it would.

Accordingly, an object of the present invention is to provide a thin film forming method capable of forming a good quality thin film at a low temperature and forming an inexpensive thin film with a simple apparatus.

[0011]

The present invention provides the following method for forming a thin film in order to achieve the above object.

[1] A plurality of substrates coated with a thin film-forming material are arranged hierarchically and at a constant interval, and are disposed in a gap formed by two adjacent substrates via a waveguide means. A method for forming a thin film, comprising performing a heat treatment while irradiating the ultraviolet light.

[2] The method of forming a thin film according to [1], wherein the waveguide means is disposed with an emission end for emitting ultraviolet light positioned at an entrance of the gap.

[3] The waveguide means comprises a waveguide plate having an ultraviolet irradiation surface, the ultraviolet irradiation surface is disposed so as to face the thin film forming surface of the substrate, and the ultraviolet irradiation surface is provided. The method for forming a thin film according to the above [1] or [2], wherein irregularities for irregularly reflecting ultraviolet light are formed on the opposite surface.

[4] The method of forming a thin film according to any one of [1] to [3], wherein the heat treatment is performed while adjusting at least one of an oxygen concentration, a nitrogen concentration, and a degree of vacuum.

In the method of forming a thin film of the present invention, as described above, heat treatment is performed while irradiating ultraviolet rays, so that a high-quality thin film can be formed at a low temperature. In addition, since a plurality of substrates are arranged hierarchically and at a constant interval, improvement in mass productivity and cost reduction can be achieved without increasing the size of the apparatus. In addition, since a gap formed between two adjacent substrates is irradiated with ultraviolet light guided through the waveguide means, a uniform thin film can be efficiently formed. Further, the waveguide means is a waveguide plate having an ultraviolet irradiation surface, the ultraviolet irradiation surface is disposed so as to face the thin film forming surface of the substrate, and the ultraviolet light is irregularly reflected on the opposite surface to the ultraviolet irradiation surface. Since the irregularities are formed, a uniform thin film can be efficiently formed by utilizing the irregular reflection of the ultraviolet rays and optimally designing the irregularities on the opposite surface.

[0017]

Embodiments of the present invention will be specifically described below with reference to the drawings.

As shown in FIG. 1, according to the thin film forming method of the present invention, a plurality of substrates 2 coated with a thin film forming material 1 are arranged hierarchically and at regular intervals, and two adjacent substrates are arranged. The heat treatment is performed while irradiating the gap 3 formed by 2 with the ultraviolet rays 5 guided through the waveguide means 4.
Hereinafter, a more specific description will be given.

In the present invention, first, a plurality of substrates 2 to which the thin film forming material 1 has been applied are arranged hierarchically and at regular intervals. There is no particular limitation on the thin film forming material 1 used in the present invention, and examples thereof include Sn-doped In and SiO ₂ . In particular, in the present invention, since a thin film can be formed at a low temperature, it can be suitably applied to a material that is difficult to apply at a high temperature.

The distance between the substrates 2 is not particularly limited, and it is sufficient that ultraviolet rays can be introduced into the gap 3 formed by the two adjacent substrates 2.

The arrangement of the plurality of substrates 2 is not particularly limited except that they are arranged in a hierarchical manner. However, from the viewpoint of effective use of space and miniaturization and mass production of the apparatus, the plurality of substrates 2 are arranged. Preferably, the ends 2a are aligned and arranged substantially in parallel. At this time, for example, the substrate holder 8 may be disposed at a predetermined position in advance, and the substrate 2 may be fixed by the substrate holder 8.

The substrate 2 is formed by two adjacent substrates 2 from the viewpoint of efficient irradiation utilizing reflection of ultraviolet rays on the surface of the substrate 2 opposite to the surface on which the thin film forming material 1 is applied. The gap 3 is preferably a closed space except for the ultraviolet ray introducing portion 3a. For example, the end 2a of the substrate
The gap 3 at the end 2 b on the opposite side from the above may be closed by an ultraviolet reflecting plate 6 arranged perpendicularly to the substrate 2. When the substrate is fixed by the substrate holder 8, the surface 8 a on the opposite side to the surface to which the substrate 2 is fixed is reflected from the viewpoint of performing efficient irradiation using the reflection of ultraviolet rays on the surface 8 a opposite to the surface 8 a. Is preferably made of a material having a high ultraviolet reflectance.

In the present invention, next, two adjacent substrates 2
Is heat-treated while irradiating the gap 3 formed by the ultraviolet rays 5 guided via the waveguide means 4.

The waveguide means 4 is not particularly limited, and examples thereof include a quartz plate and a methyl methacrylate plate.

The wave guide means 4 has an emission end 4 for emitting ultraviolet rays.
a is a gap 3 formed by two adjacent substrates 2
It is preferable to arrange it at the entrance of the device. As shown in FIG. 2, the waveguide means 4 is formed of a waveguide plate having an ultraviolet irradiation surface, and the ultraviolet irradiation surface 4c is disposed so as to face the thin film forming surface of the substrate. Irradiation surface 4c
May be formed on the opposite surface 4d. At this time, it is preferable to design the unevenness of the opposite surface 4d so that the intensity of the ultraviolet light applied to the substrate becomes uniform.

On the other hand, it is preferable that the other end 4b of the waveguide means 4 is disposed so as to face the light source section 7.

The position of the light source 7 is not particularly limited, and may be any position with respect to the substrate 2, or may be a part of the apparatus, for example, inside or outside the vacuum vessel 11.

In the present invention, the conditions of the ultraviolet irradiation are not particularly limited, and the irradiation can be performed in the same manner as in a normal thin film forming method in which the heat treatment is performed while irradiating the ultraviolet.
The conditions of the heat treatment are not particularly limited, but are preferably 300 to 700 ° C., more preferably 400 to 700 ° C.
Perform at ~ 600 ° C. Further, it is preferable to perform the treatment while adjusting at least one of the oxygen concentration, the nitrogen concentration, and the degree of vacuum.

[0029]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples.

Embodiment 1 FIG. 3 is an explanatory view schematically showing an apparatus used in one embodiment of the thin film forming method of the present invention.

As shown in FIG. 3, this apparatus is constituted by a rotary pump 12 and a turbo molecular pump 13.
A vacuum vessel 11 capable of degassing to 0 ^-6 torr is provided. In addition, a gas supply unit 14 is provided for supplying nitrogen and oxygen from the gas tank to the vacuum vessel through a pipe. The pipe of the gas supply unit 14 is provided with a main valve and a slow leak vanoleb so that the concentrations of nitrogen and oxygen during processing can be controlled.

Inside the apparatus, a plurality of substrate holders 15 made of stainless steel are horizontally arranged at intervals of 5 mm. One end 15b of each substrate holder 15 in the longitudinal direction is connected to a heating / cooling pipe 19 having a thickness of 10 mm, and a gap 23 between the substrate holders 15 is provided at the other end 15b.
Only the a side is opened.

The heating / cooling pipe 19 is provided with a heater 20 and a cooling pipe 21 to control the temperature inside the apparatus.

A plurality of 5 mm-thick quartz plates 17 penetrate horizontally through the side wall of the apparatus. This quartz plate 17
The one end 17a is arranged so as to reach the outside of the device and to face the ultraviolet light emitting device having the mercury lamp 16 in the form of a side bar. On the other hand, the other end 17b is arranged so as to reach the inside of the apparatus and to face the ultraviolet ray introducing portion 23a in the gap 23 between the substrate holders 15. Quartz plate 17
Functions as a means for guiding ultraviolet rays, whereby the ultraviolet rays generated by the external mercury lamp 16 can be guided to the ultraviolet ray introducing portion 23 a in the gap 23 between the substrate holders 15.

Next, an ITO thin film (Sn
An example in which a doped In203 thin film is formed is shown. First, a non-alkali glass substrate (30 cm x 40 cm x 1 mm)
A material for forming a thermally decomposable thin film for an ITO thin film was applied thereon by a spinner, and then dried in a bake oven at 150 ° C. for 15 minutes to evaporate an alcohol content.

Twenty substrates were set in the above-mentioned apparatus, and after deaeration in vacuum, oxygen was introduced and heated until the substrate temperature reached 300 ° C.

Next, the mercury lamp 16 was turned on, and ultraviolet rays were introduced via the quartz plate 17 from the ultraviolet ray introduction portion 23a of the gap 23 between the substrate holders 15 arranged in a hierarchy to the substrate surface. The ultraviolet rays travel while repeating reflection between the surface of the substrate 18 and the lower surface of the substrate holder 15, and reach the heating / cooling plate 19 when reaching the heating / cooling plate 19.
The light was reflected by the outer wall surface of No. 9 and proceeded to the gaps opened between the substrate holders 15 while repeating the reflection again.

In this state, after a lapse of 30 minutes, the oxygen gas was degassed in vacuum, heated to 500 ° C., and held for 30 minutes. Thereafter, the heater 20 is turned off, and the cooling gas 22a is supplied to the heating / cooling pipe 19 to start rapid cooling.
When the temperature dropped to 0 ° C., air was introduced into the vacuum vessel, and cooling water 22 b was allowed to flow through the heating / cooling pipe 19 to cool the substrate, thereby obtaining a substrate on which an ITO thin film was formed.

The substrate on which the ITO thin film was formed as described above was compared with a substrate on which the ITO thin film was formed without irradiating ultraviolet rays during the heat treatment.

The surface resistance of the substrate on which the ITO thin film was formed without irradiation with ultraviolet rays was 500 Ω / □, and the in-plane resistance variation was about 25%. On the other hand, UV irradiation
In the substrate on which the TO thin film was formed, the surface resistance was 80Ω / □, and the in-plane resistance variation was about 10%.

As described above, the substrate obtained in the embodiment of the present invention can sufficiently exhibit the effect of the ultraviolet irradiation, and
It was confirmed that a TO thin film could be formed.

[0042]

As described above, according to the coating type thin film forming method of the present invention, a thin film of good quality can be formed at a low temperature, and an inexpensive thin film can be formed with a simple apparatus. A forming method can be provided.

[0043]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing one embodiment of a coating type thin film forming method of the present invention.

FIG. 2 is a cross-sectional view schematically showing another embodiment of the coating type thin film forming method of the present invention.

FIG. 3 is an explanatory view schematically showing one embodiment of a coating type thin film forming method of the present invention.

[Explanation of symbols]

 1: Thin film forming material 2: Substrate 2a: Terminal 2b: Terminal on the opposite side 3: Gap 3a: Ultraviolet light introduction part 4: Wave guide means 4a: Terminal (emission end) 4b: Terminal (light entrance end) 4c: Ultraviolet irradiation surface 4d: Opposite surface 5: Ultraviolet light 6: Ultraviolet reflector 7: Light source 8: Substrate holder 8a: Opposite surface 11: Vacuum container 12: Rotary pump 13: Turbomolecular pump 14: Gas supply unit 15: Substrate holder 15a: Terminal (heating) 15b: Mercury lamp 17: Quartz plate (wave guiding means) 17a: Terminal (mercury lamp side) 17b: Terminal (ultraviolet ray introduction side) 18: Substrate 19: Heating / cooling Pipe 20: Heater 21: Cooling pipe 22a: Cooling gas 22b: Cooling water 23: Gap 23a: Ultraviolet ray introduction part

Claims (4)

[Claims] A plurality of substrates coated with a thin film forming material are arranged hierarchically and at a constant interval, and guided through a waveguide means to a gap formed by two adjacent substrates. A method of forming a thin film, wherein the heat treatment is performed while irradiating the ultraviolet light. 2. The thin film forming method according to claim 1, wherein said waveguide means is disposed with an emission end for emitting ultraviolet light positioned at an entrance of said gap. 3. The waveguide means comprises a waveguide plate having an ultraviolet irradiation surface, the ultraviolet irradiation surface is disposed so as to face the thin film forming surface of the substrate, and the ultraviolet irradiation surface is 2. An irregular surface for irregularly reflecting ultraviolet light is formed on the opposite surface.
Or the thin film forming method according to 2. 4. The thin film forming method according to claim 1, wherein the heat treatment is performed while adjusting at least one of an oxygen concentration, a nitrogen concentration, and a degree of vacuum.