JPH06101254B2 - Method for forming translucent conductor film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] The present invention is an improvement in a method for forming a translucent conductor film used as a translucent electrode for a panel display.

Amorphous indium tin oxide is not suitable as an electrode because of its high electric resistance. Therefore,
It is necessary to heat-treat this to convert it into a polycrystal to have a low resistance. However, the indium and tin used as targets in the amorphous indium tin oxide formation process may remain in the unreacted amorphous indium tin oxide, and this residue grows during the heat treatment process and is subsequently removed. In the patterning process, undissolved residue may remain and a short circuit between electrodes may occur.

In the present invention, in order to solve this drawback, the amorphous indium tin oxide film is formed, then patterned, and then heat-treated.

TECHNICAL FIELD The present invention relates to a method for forming a translucent conductor film. In particular, even when the translucent electrodes having a small size are formed close to each other by using this translucent conductor film, the formation of the translucent conductor film in which the short circuit between the electrodes is not likely to occur Regarding the method.

[Prior Art] A translucent conductor is required as an electrode of a display panel made of EL, liquid crystal, electrochromic material, or the like. Indium tin oxide is conventionally used as such a translucent conductor.

The method of forming indium tin oxide uses a method of using indium tin oxide as a target, and indium and tin are used as targets, and a glow discharge is generated in oxygen gas to cause them to react with each other to produce indium. There is a reactive sputtering method for converting to tin oxide.

The present invention is an improvement in the method for forming a translucent conductor film using the reactive sputtering method.

Conventionally, to form a pattern of a translucent conductor film using the reactive sputtering method, an amorphous indium tin oxide film is formed using the reactive sputtering method, and then heat treatment is applied to the amorphous indium tin oxide film. It was converted into a crystalline indium tin oxide film to have low electric resistance, and this was patterned.

[Problems to be Solved by the Invention] However, in the process of forming the above amorphous indium tin oxide film, indium or tin used as a target may remain unreacted due to abnormal glow discharge or the like. is there. This unreacted material is
Although it is a very small substance and does not cause any particular inconvenience, this nucleus grows in a heat treatment step which is performed in the next step in order to reduce the resistance of indium tin oxide, and becomes a considerably large substance. By the way, since these metals cannot be dissolved with the indium tin oxide etchant, they remain undissolved in the patterning step performed after the above heat treatment. Therefore, if the indium tin oxide film is a fine electrode or the like that is close to each other, it causes a short circuit of the electrode, that is, a so-called touch, which lowers the manufacturing yield and hinders the reliability. In addition, a transparent electrode such as a panel display using EL is required to have high smoothness in addition to high light transmittance and low resistance. This is because an insulating film having a high withstand voltage is formed on the electrodes. Therefore, the presence of the above-mentioned insoluble residue is a drawback that is unacceptable even for transparent electrodes and the like of panel displays using EL.

The present invention is to eliminate this drawback, and a short circuit occurs between electrodes even when small-sized translucent electrodes are formed close to each other using this translucent conductor film. It is another object of the present invention to provide a method for forming a translucent conductor film having a high smoothness in addition to the fear.

[Means for Solving the Problems] In order to achieve the above object, the means adopted by the present invention are:
A high resistance amorphous indium tin oxide film 2 formed by using the reactive sputtering method is first patterned to form an indium tin oxide film pattern 3.
Is formed, and then heat treatment is performed to convert it into the low-resistance translucent conductive film 4.

[Operation] The above-mentioned drawback is caused by patterning after forming an insoluble material having a large size (an insoluble material which cannot be dissolved by an indium tin oxide etchant) in the heat treatment step. Focusing attention, this process order is reversed, and if patterning is first performed, even if an insoluble matter is generated in the subsequent heat treatment process, there is no real harm.

Example Hereinafter, a method for forming a translucent conductor film according to an example of the present invention will be described with reference to the drawings.

See Fig. 1. By using the reactive DC sputtering method in which the substrate 1 such as a glass substrate is kept at a relatively low temperature of 10 ° C to 200 ° C, indium and tin are targets, and glow discharge is used. An amorphous indium tin oxide film 2 having a high surface smoothness is formed to have a thickness of several hundred to several thousand Å.

See FIG. 2. The amorphous indium tin oxide film 2 is patterned using a resist film (not shown) as a mask and hot hydrochloric acid as an etchant to form an indium tin oxide film pattern 3.

See FIG. 3. Heat treatment is performed in a nitrogen atmosphere at 500 to 600 ° C. for about 1 hour to reduce the resistance and form the translucent conductor film 4.

In this heat treatment step, insoluble nuclei generated by abnormal glow discharge and the like inevitably generated in the above reactive DC sputtering step grow, but since the patterning was performed in the previous step, this grown insoluble nucleus Does not cause a touch, and no actual harm occurs.

[Effects of the Invention] As described above, in the method for forming a translucent conductor film according to the present invention, since the amorphous indium tin oxide film is directly patterned, the heat treatment is performed. In this heat treatment step, even if the insoluble nuclei existing in the amorphous indium tin oxide film grow, the pattern is not modified. Therefore, even when small translucent electrodes are formed close to each other using this translucent conductor film, there is no risk of short-circuiting between the electrodes and high smoothness. It is possible to provide a method for forming a translucent conductor film having:

[Brief description of drawings]

1 to 3 are process diagrams of a method for forming a translucent conductor film according to an embodiment of the present invention. 1 ... Substrate (glass substrate etc.), 2 ... Amorphous indium tin oxide, 3 ... Indium tin oxide film pattern, 4 ... Translucent conductor film.

Claims (1)

[Claims] 1. A substrate (1) on which a translucent conductor film (4) is formed is kept in a temperature range of 10 ° C. or higher and 200 ° C. or lower, and oxygen gas is supplied by targeting indium and tin. Is performed to form an indium tin oxide film (2), and the indium tin oxide film (2) is patterned to form an indium tin oxide film pattern (3).
To form 50 indium tin oxide film pattern (3).
A method for forming a translucent conductor film, which comprises heat-treating in the temperature range of 0 ° C. or higher and 600 ° C. or lower to form a translucent conductor film (4) having a low resistance.