JPS627265B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for manufacturing an indium oxide conductive film by sputtering, and is used, for example, in a transparent electrode substrate for a liquid crystal display device.

<Prior art> JP-A-56-7867 discloses that a translucent conductive film is formed on a glass substrate by sputtering using a target made of an indium-tin alloy as a cathode in a mixed gas atmosphere of inert gas and oxygen. A technique for forming a is disclosed.

Japanese Patent Publication No. 52-27165 discloses that after a coating is formed on a glass substrate by vacuum evaporation using In ₂ O ₃ and SnO ₂ as evaporation sources, the coating is heated at 300°C to 600°C in an oxygen atmosphere, for example, in air. A technique is disclosed in which a conductive film with high transmittance (77 to 85%) can be obtained by firing at a temperature of .degree.

Furthermore, in Japanese Patent Publication No. 48-55267, a conductive film with a transmittance of 88% is formed by depositing indium oxide on the surface of plastic in a high vacuum and then oxidizing it in an oxidizing atmosphere at a temperature of, for example, 250°C. What was obtained is disclosed.

It is known that after a conductive film is formed on a glass substrate using an indium-tin alloy, a firing treatment is performed in an oxygen atmosphere in order to increase the light transmittance of the film. However, the above-described manufacturing technology for transparent or semi-transparent conductive films involves forming a film by fixing the substrate to be coated in a vacuum chamber while facing a target or evaporation source, and cannot be applied to mass production.

In response, the applicant installed a sputtering target on the side wall of a bell gear vacuum chamber, arranged and held a large number of glass substrates to be coated inside the sputtering target in a cylindrical shape as a whole, and continuously rotated the sputtering target. We have invented a method to do this and are implementing it as mass production equipment.

<Problems to be Solved by the Invention> Transparent electrodes for liquid crystal display devices and their lead wires in which the product of the present invention is used are usually patterned by photoetching. This pattern forming work is often performed by the user of the transparent conductive film. Therefore, when the user performs the firing process in air after pattern formation, it is preferable to perform sputtering in accordance with the firing conditions such as firing temperature and firing time, and it is more preferable that the range of firing conditions is wide. Conventionally, it has been almost impossible to satisfy this requirement, and the firing process is usually performed under conditions unilaterally specified by the membrane manufacturer.

In addition, the thickness of the transparent conductive film is 1000 Å to 2000 Å.
When the membrane is relatively thick, it is difficult to sufficiently oxidize the lower layer of the membrane during the baking process in air, and there is a problem that sufficient permeability cannot be obtained at a relatively low temperature or in a relatively short time. .

Therefore, an object of the present invention is to provide an indium oxide conductive film formed by sputtering, which has a wide range of firing temperature and firing time required to obtain a desired light transmittance, and can therefore meet the various demands of film users who manufacture electrode patterns. An object of the present invention is to provide a method for manufacturing.

<Means for Solving the Problems> The method of the present invention for achieving this object includes a target made of an indium-tin alloy provided on a part of the side wall of a bell gear type container, and a target made of an indium-tin alloy that is rotated inside the side wall of the container. A sputtering ring comprising a rotating body, a vacuum means for evacuating the inside of the container, a gas atmosphere forming means for introducing a mixed gas of an inert gas and oxygen into the container, and a power means for rotationally driving the rotating body. Using a device, a coating on which a conductive film is to be formed is attached to the rotating body, and the rotating body is rotated in an atmosphere in which the interior of the container is maintained at a predetermined degree of vacuum by the vacuum means and the mixed gas is introduced. By doing so, sputtering is performed intermittently when the surface of the coating faces the target, and a film is formed while being continuously exposed to the mixed gas atmosphere regardless of the position of the coating during rotation. It is characterized by

<Function> According to the manufacturing method of the present invention, when focusing on one coating of a rotating body, as shown in FIG. As the film is formed by alternating the time during which it is subjected to sputtering and the time when it is exposed to an oxygen atmosphere without being sputtered, the oxygen content in the film increases.
The lower limit of the firing temperature in the firing process is lowered, or the firing time is shortened. In addition, since it is subject to intermittent sputtering, thin films of 1000 Å to 2000 Å are
It becomes possible to form the film over a relatively long time of 10 to 20 minutes, making it easier to control the atmosphere and improving control accuracy.

<Example> FIG. 1 shows an example of an apparatus used in an example of the present invention.

A removable bell gear type container 2 is mounted on a base 1 to form a vacuum chamber, the exhaust hole 3 of which is connected to an exhaust system such as a vacuum pump, and the gas introduction hole 4 is connected to a gas cylinder, etc. via a pressure reducing valve. is connected to. On the base 1, a ring body 5 with teeth carved inside is rotatably provided via a ball bearing 6, and a gear 7 that meshes with the teeth of this ring body is rotationally driven by a motor 8. I can leave. As shown in the perspective view in FIG. 2, a cage-shaped rotating body 9 is fixed onto the ring body 5, and a covering boulder 10 is appropriately suspended over the entire circumference of the side surface of the rotating body 9. Attach the body. A target 11 is attached to the side wall of the container 2, and a magnetron type magnet 12 is arranged behind the target 11 to superimpose magnetism on sputtering. DC power supply 13
The cathode of is connected to the target 11, the anode is connected to the container 2, and an anode circuit is formed between the container 2 and the coating via the rotating body 9. Such targets 11 and magnets 12 can be arranged at a plurality of locations on the side wall of the container 2.

When using this device, the inside of the container 2 is evacuated, a controlled mixed gas is introduced from the gas introduction hole 4 at the same time to adjust the inside of the container to a predetermined atmosphere, and the rotating body 9 is rotated by the motor 8. , sputtering is performed by applying a DC voltage between the target and the coating.

FIG. 4 schematically shows the structure of a membrane produced by the method of the present invention. As shown in Fig. 3, a rotating sheath is sputtered intermittently during each rotation cycle, but even during the period when it is not sputtered, it is continuously exposed to a mixed gas atmosphere, which increases the oxygen content. Layers 14 containing a large amount and layers 15 containing a large amount are alternately formed.

Next, an embodiment of the present invention using such a sputtering device will be described.

80% indium, 20% tin as target material
% molar ratio of the alloy, 95% argon in the container,
A mixed gas containing 5% oxygen by volume was introduced, and the atmosphere was adjusted to an ultimate vacuum of 1×10 ⁻⁴ Torr and a gas pressure of 1×10 ⁻³ Torr. The shortest distance between the target and the covering
20cm and apply 600V DC voltage between the two poles,
A current of 25 mA/cm ² was applied. As a result, the film thickness
Light transmittance 30 based on 500Å indium oxide
A translucent conductive film of less than % was obtained.

When this was heat-treated at a temperature of 350° C. for 5 minutes, a transparent conductive film with a resistance of 800 Ω/cm ² and a light transmittance of 83% (as measured by a spectrophotometer at a wavelength of 550 nm) was obtained.

<Effects of the Invention> According to the present invention, a target made of an indium-tin alloy is disposed on a part of the side wall of a bell gear vacuum, and an inert gas and an oxygen gas are injected inside the target while continuously rotating a coating. Using a device that forms a film by sputtering on the surface of the coating in a mixed gas atmosphere, sputtering is performed intermittently only once per rotation while continuously exposing the surface of the coating to the mixed gas atmosphere containing oxygen. As a result, the firing temperature in the firing process after being taken out from the vacuum chamber can be increased to a lower temperature, or the firing time can be shortened. In addition, intermittent sputtering extends the film formation time, making it easier to control the mixed gas atmosphere from the start to the end of film formation.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an example of an apparatus used to carry out the method of the present invention. FIG. 2 is a perspective view of the rotating body and cover holder 10 of FIG. 1. Third
The figure is an explanatory diagram of the operation of the method of the present invention, and FIG. 4 is a diagram schematically showing the structure of a film produced by the method of the present invention. DESCRIPTION OF SYMBOLS 1...Base, 2...Belgear type container, 3...Exhaust port, 4...Mixed gas inlet, 6...Ball bearing, 8...Motor, 9...Rotating body, 10...
Covering body holder, 11...Target.

Claims (1)

[Claims] 1. A target made of an indium-tin alloy provided on a part of the side wall of a bell gear type container, a rotating body rotating inside the side wall of the container, and a vacuum means for evacuating the inside of the container. The coating on which the conductive film is to be formed is rotated using a sputtering device having a gas atmosphere forming means for introducing a mixed gas of an inert gas and oxygen into the container, and a power means for rotationally driving the rotating body. When the surface of the coating faces the target by rotating the rotating body in an atmosphere in which the inside of the container is maintained at a predetermined degree of vacuum by the vacuum means and the mixed gas is introduced. A method of forming an indium oxide conductive film by sputtering, characterized in that sputtering is performed intermittently, and the film is formed while being continuously exposed to the mixed gas atmosphere regardless of the position of the coating during rotation. Production method.