JPH1018026A - Production of oxide coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form oxide coating at a high speed without generating splash and to eliminate the generation of defective products caused by splash, at the time of producing oxide coating by vacuum deposition, by using oxide having specified particle size as an evaporating material and executing evaporation. SOLUTION: As the oxide, MgO, SiO2 , TiO2 , ZrO2 , Al2 O3 or the like are used. For regulating the rate of precipitating MgO to the one higher than the conventional case, MgO particles having about >=3mm particle size are used. For regulating the same to approximately double that in the conventional case or above, MgO having about >=4mm particle size is used. Furthermore, for regulating the same to approximately three times that or above, an evaporating raw material having about >=7mm shall be used. In this way, by using the evaporating material in which MgO particles having large particle size are contained, the frequency of the generation of splashes can be suppressed or the generation thereof can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an oxide film by vacuum evaporation, and more particularly, to a method for suppressing the occurrence of splash by vacuum evaporation using an oxide evaporation material having a predetermined dimension. The present invention relates to a method for producing a dielectric protective oxide film with or without generation.

[0002]

2. Description of the Related Art Since an MgO film has a long life and excellent discharge characteristics, it is used as a dielectric protection film for an AC-type plasma display (hereinafter referred to as "PDP"). Is generally manufactured by a vacuum evaporation method.

[0003] In recent years, in order to obtain an MgO film exhibiting excellent discharge characteristics, PDP manufacturers have adopted a vacuum deposition method as a method for producing the MgO film and are examining a mass production system. As an evaporation raw material for producing such an MgO film,
MgO crushed to a particle size of 1 mm or more and less than 3 mm
It is known to use evaporative materials such as crystal grains or sintered products made by baking and solidifying MgO powder.

[0004]

However, when the above-mentioned conventional evaporation material is heated by an electron gun using an electron beam evaporation source to perform vacuum deposition of MgO, the heating power of the electron gun is increased. Then, when trying to increase the deposition rate, in the process of evaporation, a splash from the evaporating material occurs, particles adhere to the obtained film, and defective products are generated, so that the deposition rate cannot be increased. There are drawbacks and a solution has been desired.

[0005] The above-mentioned splash means the following phenomena here. Usually, when evaporating a metal or oxide in a vacuum by electron beam heating, the evaporating raw material becomes steam when the temperature exceeds its melting point,
Evaporation starts on the order of uniform atoms (several Å). Splash refers to a uniform vapor flow from the vaporized raw material due to some cause during heating (for example, explosion of bubbles contained in the material due to thermal shock, electrostatic charge-up, etc.) during the evaporation process. Mixed with several μm to 100 μm
A phenomenon in which a lump of a visible size bumps and pops out is a problem in making a fine device. Such a phenomenon is generally likely to occur frequently during the deposition of an oxide, and in the case of an oxide having a high melting point such as MgO, an occluded gas in an evaporating material, particularly, poor heat conduction, and charge-up (static electricity). It is considered that this may be caused by the occurrence of the phenomenon.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for improving the drawbacks of the prior art and enabling a high-speed deposition of an oxide film with or without the occurrence of splash. .

[0007]

According to the present invention, there is provided a method for producing an oxide film by vacuum evaporation using an oxide evaporating material, wherein an oxide having a particle diameter of 3 mm or more is generally used as the evaporating material. Then, evaporation is performed to deposit an oxide film.

The evaporating material is preferably at least 4 mm,
More preferably, it is an oxide having a particle size of 7 mm or more. The upper limit value is not particularly limited, but may be any value as long as it is less than or equal to the maximum size that can be supplied and stored in a container for storing the evaporation material in the evaporation source, for example, a hearth used in a normal electron beam evaporation source.

The above-mentioned particles are, for example, one massive oxide crystal (eg, MgO crystal) which is electro-fused and crystal-grown.
Therefore, it is obtained by crushing into irregular shapes by Yumbo, etc., and usually has severe surface irregularities.

[0010] The oxide evaporating material is a block material, for example, a block material cut out from a block of oxide crystal (eg, MgO crystal) into a predetermined size by a diamond cutter or the like. It may be relatively smooth. Its dimensions are not particularly limited,
Any oxide block material having a dimension equal to or less than the maximum dimension that can be accommodated in a container for accommodating the evaporation material in the evaporation source may be used, and one or a combination of two or more may be used. For example, as a dimension less than the maximum dimension that can be supplied and stored in a hearth used in a normal electron beam evaporation source,
For example, 20 × 20 × 20 mm to 50 × 40 × 40 mm
Oxide blocking materials within a range may be used.

The oxide is, for example, MgO, Si
Oxides such as O ₂ , TiO ₂ , ZrO ₂ or Al ₂ O ₃ .

[0012]

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

FIG. 1 shows an exemplary electron beam evaporation source device for use in the method of the present invention. In FIG. 1, 1 is an electron gun, 2 is a path of an electron beam from the electron gun 1, 3 is a water-cooled copper hearth, 4 is a film thickness monitor, 5 is a shutter, 6 is a vacuum tank, 7 is a focusing coil, 8 is A swing coil, 9 is a deflection coil, 10 is an evaporating material, and 11 is a viewing window. A hearth 3, a film thickness monitor 4, a shutter 5, and a deflection coil 9 for storing the evaporation material 10 are arranged at predetermined positions in the vacuum chamber 6, and the shutter 5 and the film thickness monitor 4 store the evaporation material. It is provided at a position facing the hearth 3. Output electron beam 2 from electron gun 1
Is curved and guided into the hearth 3 from above by the action of the focusing coil 7 and the oscillating coil 8 provided around the connection path between the vacuum chamber 6 and the electron gun 1, and thus, into the hearth. Heat evaporation of the contained evaporation material 10 is performed,
Vapor deposition is performed on a predetermined substrate.

(Example 1) An MgO film was vacuum-deposited by using the electron beam evaporation source apparatus shown in FIG. 1 as described below.

An MgO evaporating raw material 10 having a particle size of 3 to 4 mm (supply amount: about 80 cm ³ (5 × 4 × 4 cm), a density of 3.51 g / cm ³ and a bulk density of 0.4 Water-cooled copper hearth 3 (capacity: 8 g)
0 cm ³ (5 × 4 × 4 cm), and a predetermined pressure (heating pressure: 1.3) is applied to the inside of the vacuum chamber 6 via a vacuum exhaust system.
× 10 ^-2 Pa), and then M
gO predetermined area portion of the evaporation material (38cm ²⁾ was heated (heating conditions: When the evaporation surface area 38cm ^2, about 4.0kW
(Deposition rate 4.0 nm / s) and about 16.0 kW (deposition rate 30.0 nm / s), the deposition rate is 0.5 nm.
/ S interval. The relationship between the power and the deposition rate is proportional. ), And MgO was evaporated and deposited on a predetermined substrate. As a result of this experiment, the maximum deposition rate at which MgO could be formed without generating a splash was:
It was 5.0 nm / s.

(Embodiment 2) 3 to 4 mm in Embodiment 1
4-5m instead of MgO evaporation raw material having a particle size of
m, 7 to 8 mm, 10 to 12 mm, or the method of Example 1 was repeated, except that a MgO evaporation raw material having a particle size of 14 to 15 mm was used. As a result, the maximum deposition rates at which MgO could be formed without generating a splash were 9.0 nm / s, 12.0 nm / s, and 13.5 nm, respectively.
/ S and 15.0 nm / s.

(Comparative Example 1) 3 to 4 mm in Example 1
Instead of MgO evaporation raw material having a particle size of 1 to 3 mm
Alternatively, the method of Example 1 was repeated except that a MgO evaporation raw material having a particle size of 2 to 3 mm was used. as a result,
The maximum deposition rate at which MgO could be deposited without generating a splash was only 4.2 nm / s.

(Embodiment 3) 3 to 4 mm in Embodiment 1
The method of Example 1 was repeated, except that an uncrushed 50 × 40 × 40 mm block-shaped MgO evaporating raw material was used instead of the MgO evaporating raw material having a particle size of, and the deposition rate was increased in accordance with the experiment. Was. As a result, the maximum deposition rate at which MgO could be formed without splash was 3
It was 5.0 nm / s.

FIG. 2 shows the results obtained in the above Examples and Comparative Examples. In FIG. 2, the horizontal axis represents the Mg used.
The particle diameter range of O is shown, and the vertical axis shows the maximum deposition rate at which an MgO film can be obtained without generating a splash during vacuum evaporation. As is evident from these results, in order to increase the MgO deposition rate as compared with the conventional case, it is required that
mmO particles having a particle size of at least mm may be used,
In order to increase the size to approximately twice or more of the conventional case, MgO having a particle size of about 4 mm or more may be used. Raw materials may be used. Thus, when considering a mass production line by high-speed deposition of an MgO film, the frequency of occurrence of splash can be suppressed or eliminated by using an evaporation material having MgO particles having the largest possible particle size.

When a higher deposition rate is required, an oxide block material having a size smaller than the maximum size that can be accommodated in a container for accommodating the evaporation material in the evaporation source, for example, a normal electron beam evaporation A 50 × 40 × 40 mm oxide block material that can be supplied and stored in a hearth used as a source is directly irradiated with an electron beam to evaporate MgO, thereby forming a high-speed MgO film without splash. Is possible. The size of the MgO block material mentioned here is shown as an example of the size that can be stored in the water-cooled copper hearth used in the above embodiment, but the MgO block material of a larger size,
Further, by increasing the power supply capacity by using a large-capacity electron gun power supply, the deposition rate can be further easily increased. Further, depending on the volume of the hearth, a block material having a size smaller than the illustrated size may be used, or a block material having a size smaller than the hearth volume may be used. The above-mentioned block materials can be used in combination.

Further, instead of the MgO evaporating material, Si
When the method described in the above Examples 1 to 3 is repeated using an oxide such as O ₂ , TiO ₂ , ZrO ₂ or Al ₂ O ₃ , similar to the case of these Examples, the generation of the splash Each oxide film was deposited and deposited at a high speed, with or without suppression.

Furthermore, in the above embodiment, the vacuum deposition method using an electron gun was described. In addition, the vacuum deposition method using a plasma gun, reactive deposition using these guns, In the same manner as in these examples, the above-mentioned oxide film could be vapor-deposited and produced at a high speed without splashing in the same manner as in these examples.

[0023]

According to the method for producing an oxide film of the present invention,
Since an oxide having a particle size of 3 mm or more or a block-shaped oxide is used as an evaporating material, it is possible to form an oxide film at a high speed without generating a splash, and to deposit an oxide film required in a mass production line. Since the size of the evaporating material can be selected according to the speed and the evaporating material can be evaporated, it is possible to eliminate the frequency of defective products caused by the splash.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an electron beam evaporation source device used in the method of the present invention.

FIG. 2 is a graph showing the relationship between the particle size of MgO and the maximum deposition rate at which an MgO film can be obtained without generating a splash during vacuum deposition.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electron gun 2 Electron beam path 3 Water-cooled copper hearth 4 Film thickness monitor 5 Shutter 6 Vacuum chamber 7 Focusing coil 8 Swing coil 9 Deflection coil 10 Evaporation material 11 Viewing window

Claims (7)

[Claims] 1. A method for producing an oxide film by vacuum evaporation using an oxide evaporation material, wherein the evaporation material comprises 3
performing evaporation using an oxide having a particle size of at least mm,
A method for manufacturing an oxide film, comprising depositing an oxide film. 2. The method according to claim 1, wherein the evaporation material is an oxide having a particle size of 4 mm or more. 3. The method according to claim 1, wherein the evaporation material is an oxide having a particle size of 7 mm or more. 4. The method according to claim 1, wherein the oxide is MgO, SiO ₂ , Ti.
The method according to claim 1, wherein the method is O ₂ , ZrO _2, or Al ₂ O ₃ . 5. A method for producing an oxide film by vacuum deposition using an oxide evaporation material, wherein the evaporation material comprises:
A method for manufacturing an oxide film, comprising: evaporating an oxide using at least one oxide block material having a size equal to or less than a maximum size that can be accommodated in a container accommodating an evaporating material to deposit an oxide. 6. The method according to claim 1, wherein the raw material is 20 × 20 × 20 mm.
6. The method according to claim 5, wherein the oxide block material has a size of about 50 * 40 * 40 mm. 7. The method according to claim 1, wherein the oxide is MgO, SiO ₂ , Ti.
7. The method according to claim 5, wherein O ₂ , ZrO _2, or Al ₂ O ₃ is used.