JPH02129842A - Manufacture of conductive thin film - Google Patents

Abstract

PURPOSE:To manufacture a conductive thin film having a big area with a good yield by forming a conductive thin film on a substrate in a state where an insulation substrate to be coated is held in an electrically insulated state from a coating device body. CONSTITUTION:A substrate 1 is held by an holder 2 consisting of stainless steel or the like. A tray 3 is earth-connected through the device body. An insulator 5 such as a ceramic insulates the substrate holder 2 from the tray 3. A gap by 5a is opened between the holder 2 and the tray 3 by this insulator 5, while a part of the surface also of the insulator 5 is coated with a conductive thin film by coming round of a target material so that a gap 5b between the insulator 5 and the holder 2 as well as the length 5c as a barrier from the target material of the insulator 5 through the tray 3 are necessary in order to more completely perform insulation. Thereby, a phenomen, in which charged electrons on the substrate flow out at a stretch through a conductive film to the device body side is excluded while causing no film coming-off.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for forming a conductive thin film on an insulating substrate.

[Prior art] Thin film manufacturing methods generally include vapor deposition, ion blating, sputtering, and CVD, but among these methods, the method is relatively easy, provides high film adhesion, and is excellent in mass production. The sputtering method is often used, and recent progress has been made in increasing the size of the area.

FIG. 4 shows the configuration of a conventional general DC bipolar sputtering apparatus. In the figure, 1 is a substrate such as glass, 2 is a substrate holder 3 that supports the substrate 1, is a tray (also called a transport cart in the case of a per-leaf type sputtering apparatus), and 4 is a target material. The substrate holder 2 and the tray 3 are usually made of a conductive material such as stainless steel, and the tray 3 is electrically connected to the main body of the apparatus in some way.

[Problems to be Solved by the Invention] When forming a conductive thin film on an insulating substrate using the conventional sputtering method described above, thread-like film peeling may occur on the substrate surface, and this defect increases the film forming area. As a result, the rate of occurrence becomes higher and the yield of film formation on large substrates is significantly lowered. The cause of this defect is that in the sputtering method,
Normally, the substrate side is set to a ground potential and a negative electric field is applied to the sputter target side to generate a discharge, but in the early stage of film formation, the substrate is an insulator, so electrons emitted from the cathode charge the substrate.

For this reason, for example, if the substrate holder is electrically connected to the main body of the device, film formation will progress and a conductive thin film will be formed at the boundary between the substrate and the substrate holder, and the moment electrical conduction occurs, the electrons that were previously charged on the substrate will be removed. It flows all at once to the main body of the device through the conduction point between the board and the board holder. It is thought that the current generated at this time causes film peeling on the substrate surface. Due to this defect, there is a problem in that it is difficult to manufacture a conductive thin film with a good yield, especially in a large area.

It is an object of the present invention to solve the problems in the prior art and to manufacture a conductive thin film over a large area with good yield.

[Means for Solving the Problems] In the present invention, a conductive thin film is formed on an insulating substrate on which a film is to be formed, while the insulating substrate is held electrically insulated from the main body of a film forming apparatus.

[Function] When a conductive film is formed on an insulating substrate, since the substrate is insulated from the device body, the phenomenon in which electrons charged on the substrate flow all at once through the conductive film to the device body side is eliminated, and film peeling is prevented. does not occur.

[Example] FIG. 1 is an example of a sputtering apparatus according to the manufacturing method of the present invention, and shows the same DC bipolar sputtering apparatus as in FIG. 4. A substrate 1 made of glass or the like is held in a holder 2 made of stainless steel or the like. Reference numeral 3 denotes a tray, which is connected to earth via the main body of the apparatus (not shown). 4 is the target.

Reference numeral 5 denotes an insulator such as ceramic that insulates between the substrate holder 2 and the tray 3. Due to this insulator 5, there is a gap 5a between the holder 2 and the tray 3, but as the target material wraps around, a conductive thin film is also formed on a part of the surface of the insulator 5, making it more perfect. In order to provide insulation, a length 5c is required as a gap 5b between the insulator 5 and the holder 2 and as a barrier for the tray 3 to protect the insulator 5 from the target material. These gaps and lengths 5a-5
c varies somewhat depending on the substrate, target size, distance between cathode and anode (C-A), flatness of substrate holder, film forming conditions, etc., but for 5a, it is 0.3~
1.5 n++n, 0.1 to 1.0 for 5 b
+nm and 5c, approximately 10 to 40II1m is appropriate.

As shown in FIG. 1, according to the present invention, since the substrate 1 and the substrate holder 2 are insulated from the main body of the apparatus, the charged electrons on the substrate 1 and the substrate holder 2 do not leak out. This makes it possible to prevent thread-like film peeling due to electron outflow, which is a technical problem, and leads to a significant improvement in yield.

Although not shown in the figure, it goes without saying that the same effect can be obtained even if an insulator is placed between the substrate 1 and the substrate holder 2.

Note that in the manufacturing method of the present invention, film formation is completed while the substrate or substrate holder remains charged, so it is preferable to remove static electricity from the substrate or substrate holder by blowing for static elimination after film formation to prevent dust from adhering to the film.

Specific examples of the present invention are shown below. With the configuration shown in FIG. 1, 2000 transparent electrodes (ITO) were formed on 50 glass substrates each having a substrate size of 300x3.0Oxt1.0 (mm). The discharge pressure at this time was 3 mTorr, the current was 2 A, the distance between C and A was 50 mm, and ceramic was used as the insulator 5 in Fig. 1, and 5 a = 0.
．． 5mm, 5b=0.1mm, 5c=
It was set to 30 mm. As a result, the film formation yield was 100%, and no film peeling due to electron outflow was observed. moreover,
The results of film formation with varying substrate sizes are shown graphically in FIGS. 2 and 3.

Figure 2 shows the results of the defective rate when changing the substrate size with the configuration of the present invention, and for reference, Figure 3 shows the results of the defective rate when a film was formed with the conventional configuration shown in Figure 4. show.

As shown in Figure 3, in the conventional manufacturing method, the substrate size is 50 mm.
When the area exceeds about 0 cm2, many defects occur due to the outflow of electrons, and the defective rate increases rapidly as the area increases. On the other hand, as shown in FIG. 2, the manufacturing method of the present invention resulted in a defective rate of 1% or less even when the substrate size was about 2000 cm2.

The insulating substrate on which the conductive thin film described above is formed can be used as an insulating substrate constituting a liquid crystal cell, for example, a strong-talk liquid crystal cell.

Further, in the present invention, in addition to the sputtering method described above, RF (radio frequency) sputtering, plasma CVD, and ion blating method can be applied.

[Effects of the Invention] As explained above, the present invention solves the problem of the conventional technology of film peeling due to the outflow of electrons during the formation of a conductive film, and makes it possible to manufacture a conductive thin film over a large area with good yield. become.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a DC bipolar sputtering apparatus according to the present invention, Fig. 2 is a graph showing the defective rate of thin films produced by the apparatus shown in Fig. 1, and Fig. 3 is a conventional DC bipolar sputtering apparatus. FIG. 4 is a graph showing the defective rate of thin films manufactured by the method, and FIG. 4 is a configuration diagram of a conventional DC bipolar sputtering apparatus. 1: Substrate, 2: Substrate holder, 4: Target, 5: Insulator. % @ l) l ト懺t♂

Claims (10)

[Claims] (1) A method for producing a conductive thin film, which comprises forming a conductive thin film on an insulating substrate to be deposited while electrically insulating the substrate. (2) The method for manufacturing a conductive thin film according to claim 1, wherein the substrate is directly mounted and held on an insulator. (3) The method for producing a conductive thin film according to claim 1, wherein the substrate is held by a substrate holder, and the substrate holder is mounted and held on an insulator. (4) The method for manufacturing a conductive thin film according to claim 1, wherein the conductive thin film is formed using a DC bipolar sputtering method. (5) A substrate holder for holding an insulating substrate to be deposited, a tray for mounting the substrate holder in the film deposition apparatus main body, and a tray for electrically insulating the substrate from the film deposition apparatus main body. An apparatus for carrying out the method for manufacturing a conductive thin film according to claim 1, characterized in that the apparatus is made of an insulator. (6) The apparatus for producing a conductive thin film according to claim 5, wherein the insulator is provided between the substrate and the substrate holder. (7) The apparatus for producing a conductive thin film according to claim 5, wherein the insulator is provided between the substrate holder and the tray. (8) The apparatus for producing a conductive thin film according to claim 5, wherein the film forming apparatus is a DC bipolar sputtering apparatus. (9) A patent characterized in that the substrate holder is mounted on the tray via an insulator, and a plate material for preventing target material from flying off is provided on the outer edge of the lower surface of the substrate holder at a distance from the holder. An apparatus for producing a conductive thin film according to claim 8. (10) The apparatus for producing a conductive thin film according to claim 9, wherein the plate material for preventing flying of the target material is formed by protruding the lower edge of the tray.