JPS5918511A - Method of forming transparent conductive film on substrate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a transparent conductive film on a substrate, and particularly to a method for forming a transparent conductive film made of indium oxide, tin oxide, and ammonium oxide on a substrate by sputtering.

Conventionally, as a method for forming a transparent conductive film on a substrate, a target made of an alloy of indium and tin and a glass substrate are placed in a vacuum container facing each other, and an inert gas containing oxygen is introduced into the vacuum container. A so-called sputtering method is known in which a transparent conductive film of indium oxide containing tin oxide is formed on the glass substrate by sputtering the target while maintaining the target at a negative potential with respect to the glass substrate. .

The transparent conductive film thus formed on the glass substrate is heat-treated in the atmosphere at a flow rate of 70 to 60 minutes at a flow rate of 0.degree.

Transparent conductive films used in liquid crystal display devices are required to have high transparency and high electrical conductivity. To form a conductive film with high transparency and high electrical conductivity by the sputtering method, an inert gas containing 5% to 30% by volume of oxygen is introduced into a vacuum container, and the inside of the container is heated at 2×/ , 0-3 TOrr~! This can be achieved by sputtering while maintaining the pressure at x1O-2Torr ty).

However, since the indium in the conductive film formed under the above sputtering conditions is not sufficiently oxidized, metallic indium aggregates during the heat treatment process, causing an optical defect that shines white in reflected light, and also reduces the flatness of the surface of the film. It causes the disadvantage of loss.

The present invention was made in order to eliminate the above-mentioned drawbacks of a transparent conductive film of indium oxide containing tin oxide,
In the present invention, a target made of an alloy and a substrate to which a metal oxide film constituting the alloy is to be attached are placed in a vacuum container, an inert gas containing oxygen is introduced into the vacuum container, and the target is exposed to the substrate. A method for depositing and forming a metal oxide film on the substrate by applying a negative voltage to the target and sputtering the target, in which an alloy of indium, tin, and antimony is used for the target, and the amount of antimony is This is a method for forming a transparent conductive film on the substrate, characterized in that the ratio is 0.3 to 3 weight per 100 weight of indium.

(3) The present invention uses usually metallic indium 100 as a target.
Preference is given to using indium-tin-antimony alloys containing from 3 to 3 parts by weight of antimony metal in alloys containing from 3 to 0 parts by weight of tin metal.

By using an indium tin target containing 0.3 to 3 weights of antimony per 100 weights of indium, the present invention eliminates the agglomeration of metallic indium that causes an optical defect that shines white in reflected light, and also improves the flatness of the film. It does not cause the disadvantage of impairing sex.

It is thought that this is because antimony oxide contained in the conductive film suppresses the movement of metallic indium during heat treatment.

When the amount of antimony added to the target alloy is less than 0.3 weight per 100 indium weight, the effect of suppressing the agglomeration defects of metallic indium in the conductive film formed becomes small, and aggregation defects due to metallic indium occur. However, if the amount is more than 3 weight per 100 weight of indium (4'), the electrical conductivity of the conductive film becomes low.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

A cathode having a target 3 made of an indium-tin-antimony alloy plate with a diameter of 100 mm and a thickness of 1 mm on its surface and a glass plate j with a size of 100 mm x 100 mm and a thickness of Q mm are installed in a vacuum vessel. An anode l is provided.

A magnet 7 is provided on the back side of the cathode, and each magnet 7 is connected to a yoke g.
A magnetic path is formed between the two, and it is attached to the vacuum vessel L via an insulator. The vacuum container l has an exhaust port // to 11! ×1
After evacuation to O-6 TOrr, argon gas containing is volume % oxygen gas is supplied through the gas inlet IO, and the gas supply and exhaust port 1 are connected to equilibrate at 3X10-3 TOrr. The outer orifice valve was adjusted.

The power supply t is connected to the cathode 2, and the voltage is about -rsov with respect to the anode 2.
voltage is applied to generate a discharge.

Although the cathode is not shown, a water cooling device is provided and the cathode is cooled by water.

Alloys with various compositions were used for the target 3, and after forming a film with the thickness of the film, the film was baked in the atmosphere for 30 minutes to obtain a transparent conductive film. Table 1 shows the electrical and optical properties of the obtained transparent conductive film and the presence or absence of agglomeration defects of metallic indium in the transparent conductive film.

Table 2 shows the electrical and optical properties of transparent conductive films of comparative examples obtained in the same manner as in this embodiment and the presence or absence of agglomeration defects of metallic indium in the transparent conductive films.

The agglomeration defects of metallic indium shown in Tables 7 and 2 are defects observed under a microscope with a magnification of 300 times, and are covered by lumps of metallic indium with a diameter of several microns.

As is clear from Table 7 and Table 2, the transparent conductive film according to the present invention does not have the agglomeration defect of metallic indium that occurs in conventional transparent conductive films, and it is clear that it has high transmittance and high electrical conductivity. .

[Brief explanation of the drawing]

Figure E is a sectional view showing a sputtering apparatus according to the present invention. O/Front fang 2 Front/: Vacuum container 1.2: Cathode, 3: Target. tI: Anode, J Niglass plate, Otsu: Power supply. 7: magnet, lr: yoke, tsu: insulator. 10: Gas inlet, //: Exhaust port Figure 1 (7) Procedure amendment (method) / Indication of case Patent application 1983-/, 26g7g No. 1 Name of the invention Forming a transparent conductive film on a substrate Method 3 Relationship with the case of the person making the amendment Patent applicant address 4-8 Doshomachi, Higashi-ku, Osaka-shi, Osaka Name (
lθθ) Nippon Sheet Glass Co., Ltd. Representative Nobu Saiga, Representative 2 Correction. Target O"'"10#2tB (!a8)
7 Contents of amendment 1. Page 3 of the specification, line 7g to line 20 are deleted 02, between page 7 of the specification, line 1i and line 79 (below the table): 1 is a sectional view showing a sputtering apparatus showing the present invention."

Claims (1)

[Claims] A target made of an alloy and a substrate to which a metal oxide film constituting the alloy is to be attached are placed in a vacuum container, an inert gas containing oxygen is introduced into the vacuum container, and the target is heated to a negative temperature with respect to the substrate. In the method of depositing and forming a metal oxide film on the substrate by sputtering the target by applying a voltage, the target is an alloy of indium, tin, and antimony, and the amount of the antimony is set to 100% by weight of the indium. A method for forming a transparent conductive film on the substrate, characterized in that the ratio is 0.3 to 3 weight relative to the substrate.