JPH0680565B2 - Substrate with conductor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductor-bearing substrate in which a metal coating is formed on a desired portion of a transparent conductive film.

[0002]

2. Description of the Related Art A transparent conductive film containing indium oxide, tin oxide or the like as a main component is widely used as an electrode of a substrate of a display element such as liquid crystal or electrochromic, or an electrode of a solar cell. It is possible to form a metal coating on a required portion of the transparent conductive film for the purpose of reinforcing the strength and reducing the resistance value when soldering on the transparent conductive film or when it is used as a connection terminal for sockets. Often done.

As a method for forming this metal coating, a transparent conductive film is formed by a so-called electroless plating method using a plating solution containing nickel sulfate or nickel chloride as a raw material of nickel cation and containing hypophosphite as a reducing agent. Ni-P on top
A method of applying a plating film is known. Furthermore, a method for forming a metal coating by an electrolytic plating method, a metal vapor deposition method, a sputtering method, etc. is also known.

As a method of forming a transparent conductive film on a substrate, for example, the following method is known. 1) A method of obtaining a transparent conductive film by sputtering metallic indium, metallic tin or an alloy of both in an oxygen atmosphere. 2) A method in which indium oxide, tin oxide, or a mixture of both is vapor-deposited in a high vacuum, then heated in air, and secondarily baked to obtain a transparent conductive film. 3) A method of obtaining a transparent conductive film by vapor-depositing indium oxide, tin oxide or a mixture of both in a low pressure oxygen atmosphere.

However, it is difficult to obtain a practically sufficient adhesion strength between the transparent conductive film formed by either method and the metal film. Therefore, as a method for improving the adhesion with the metal film using the transparent conductive film prepared by the conventional method described above, a method of mechanically polishing the surface of the transparent conductive film, a method of performing a chemical etching treatment. Etc. have been proposed. This is a method of forming fine unevenness on the surface of the transparent conductive film to generate a so-called anchor effect.

[0006]

It is desired to obtain a further effect in the method of roughening the surface of the transparent conductive film formed on the substrate by the conventional method by a method such as mechanical polishing or chemical etching to improve the adhesion. In some cases, it is necessary to increase the polishing amount in mechanical polishing or the etching amount in chemical etching. However, when fine patterning is performed, disconnection due to partial disappearance of the transparent conductive film (such disconnection occurs at a certain rate depending on the degree of surface roughening) or an increase in resistance value. Occurs and there is a limit to increasing the degree of roughening.

Further, mechanical polishing has drawbacks in productivity and in uniformity of treated surface. In addition, the adhesion between the metal coating and the metal coating, which is increased by conventional methods such as mechanical polishing and chemical etching, was only about 30 to 50% greater than that when the surface was not roughened.

The present invention has been made to solve the above-mentioned drawbacks of conventional conductors, and it is possible to form a transparent conductive film without causing a phenomenon such as a partial disappearance of the transparent conductive film or an increase in resistance value. It is an object of the present invention to provide a substrate with a conductor that has an extremely high adhesion to a metal coating.

[0009]

That is, according to the present invention, a metal coating is formed on a required portion of a transparent conductive film of a substrate having a transparent conductive film containing at least one of indium oxide and tin oxide as a main component. In the case of a substrate with a conductor, the transparent conductive film has a crystal grain size in the> 222 <direction of 400Å in the X-ray diffraction method.
Provided is a substrate with a conductor, which is the above film.

The inventors of the present invention have found that the conventional transparent conductive film of the substrate with a conductor has a limit in improving the adhesion with the metal film even if mechanical polishing or chemical etching is performed. Research was conducted to improve the power by improving the characteristics of the transparent conductive film. As a result, it was discovered that the fact that the crystal grain size of the transparent conductive film was smaller than 400Å was the cause of the weak adhesion with the Ni-P metal film.

The present inventors have found that when a metal coating is provided on the transparent conductive film having a particle size of 400 Å or more, the adhesion is improved, and particularly the adhesion with the Ni-P metal coating is more than double the adhesion. It has been discovered that it has excellent properties that show power.

The mechanism of the crystal grain size relating to the adhesion with the metal coating can be explained as follows. Generally, in order to improve the adhesion between the substrate and the metal plating film, it is effective to create irregularities on the surface to increase the effective contact area, and to create a surface that causes the so-called anchor effect. It has been known. In the case of a transparent conductive film, the irregularities on the outermost surface become larger as the crystal grain size becomes larger.

That is, assuming that the constituent crystal grains are substantially spherical, the size of the surface irregularities matches the radius of the crystal grains. Further, as the crystal grain size increases, fine voids are generated between the adjacent grains, and the voids are filled with the metal coating, so that the anchor effect is produced.

It can be confirmed by measuring the refractive index of the film that the voids are generated when the crystal grain size is large. That is, while the indium oxide single crystal and the tin oxide single crystal show a refractive index of 2.00, the transparent conductive film having a particle size of 400 Å or more, which shows a high adhesion in the present invention, shows a refractive index of 1.90 to 1.93, which is considerably lower than this. This is because the transparent conductive film used in the present invention has a low crystal packing density and has many voids in the film.

Further, the refractive index of the transparent conductive film used for the conventional substrate with a conductor is generally 1.97 to 2.00, and a clear difference is recognized. As described above, the transparent conductive film used in the present invention has a crystal grain size in the> 222 <direction of X-ray diffraction of 400
Å It is defined as above, but it is possible to give a clear index from the viewpoint of the mechanism that the adhesion force with the metal film is generated.

The transparent conductive film having a crystal grain size in the> 222 <direction in the X-ray diffraction method of the present invention of 400 Å or more can be prepared as follows. As a material for the transparent conductive film, metal indium, metal tin, or an alloy in which both are mixed at a constant ratio is used. Oxygen is introduced into the chamber during the formation of the conductive film to adjust the pressure to 3 × 10 −3 Torr to 5 × 10 −3 Torr. The oxygen partial pressure needs to be changed according to the distance between the substrate and the evaporation source, but when the deposition rate is 1 to 3 Å / sec, the mean free path is 10 to 50% of the distance between the substrate and the evaporation source. The oxygen partial pressure is desirable. As a result, the vapor-deposited metal indium or metal tin almost certainly collides with oxygen molecules, and the film vapor-deposited on the substrate has oxygen molecules occluded in the film.

In the conventional method, many methods have been reported for producing a transparent conductive film using metal indium, metal tin, or an alloy in which both are mixed in a fixed ratio as a vapor deposition material. Heating to 500 ° C is usually practiced. In the substrate with a conductor of the present invention, the conductive film is formed while keeping the substrate temperature at room temperature to 100 ° C. It can be confirmed from an X-ray diffraction image that the conductive film thus formed is in an amorphous state because a large amount of oxygen is stored in the film. This substrate is then placed in air for 200
Secondary oxidation is carried out at ℃ to 500 ℃ until it becomes transparent.

By this secondary oxidation, the conductive film changes from an amorphous state to a polycrystalline film. The higher the secondary oxidation temperature is, the more desirable for the growth of crystal grains. However, since the oxidation is accompanied in the high temperature region, the resistance value increases. Since a crystal grain size in the> 222 <direction of 400 Å or more is practically sufficient for improving the adhesion with the plated coating, a secondary oxidation temperature for obtaining such a grain size is preferably about 300 ° C.

Here, the vapor deposition method has been described as the film forming method, but the same effect can be obtained by the sputtering method. Adjust the oxygen partial pressure during sputtering,
By forming an amorphous film in which a large amount of oxygen is stored during film formation, it is possible to cause crystal grain growth during secondary oxidation.

The crystal grain size in the> 222 <direction in the X-ray diffraction method is, for example, “Experimental Chemistry Lecture 4 Solid State Physical Chemistry” edited by the Chemical Society of Japan, page 238 and below, magazine “Measurement Technology”, November 1977, page 86. And page 89, and the magazine “Coloring materials” 1970, 43, 579 and 580, etc., can be measured by a known method.

As an example of the measuring method, the crystal grain size is D,
The wavelength of the X-ray used is λ (1,542 for Cu-Kα ray)
Å), the Bragg angle is θ, and the spread of the diffraction line purely based on the size of the crystal grain is β, and the crystal grain diameter D is obtained from the following equation. D = 0.9 λ / (β cos θ)

The spread β of the diffraction line is obtained by the following method. That is, first, the diffraction profile of the (101) plane is measured using a Cu-Kα ray generated under the conditions of 40 KV and 100 mA as an X-ray source. Measurement conditions are goniometer speed 1/4 /
Min, chart speed 10 mm / min, slit width is divergence slit 1/2 °, receiving slit 0.3 mm
, Scattering slit 1/2 °.

For the profile obtained, the width B0 at half the height from the background to the diffraction peak is measured. Double Bragg angle θ shown in Fig. 2 Kα for 2θ
The split width Δ of the (101) plane with respect to the angle 2θ is read from the relationship between the split widths Δ of the 1st line and the Kα 2 line. Then, based on the values of the width B0 and the split width Δ, the value B 1 is obtained from the relationship between the ratio Δ / B0 and the ratio B / B0 shown in FIG. High-purity silicon (purity 99.99%) is used as a standard sample, and each diffraction profile is measured under the above slit condition to obtain the half-width b 1. This is plotted against the angle 2θ, and the half width b
Make a graph showing the relationship between and the angle 2θ. (101) face angle
The ratio b / B can be obtained from the half-width b corresponding to 2θ, and the spread β of the diffraction line can be obtained from the relationship between the ratio b / B and the ratio β / B shown in FIG.

[0024]

EXAMPLE As shown in the sectional view of FIG. 1, the partial pressure of oxygen during vapor deposition was kept at 3 × 10 −3 Torr on a soda glass substrate 1,
In-Sn 8: 2 alloy with electron beam heating to a film thickness of 500
Molded to Å. Substrate 1 temperature is room temperature and deposition rate is 5
Å / sec. After vapor deposition, this substrate 1 is placed in air
Heat treatment was performed at 300 ° C for 1 hour. As a result, the semi-transparent In-Sn film is oxidized and becomes transparent, and the transparent conductive film 2
It was confirmed by the X-ray diffraction method that the particles forming the transparent conductive film 2 were grown to a diameter of about 450 Å at the same time as the formation of the above.

The substrate 1 having the transparent conductive film 2 formed thereon was washed with an alkali and then subjected to known catalyst treatment and activation treatment. Then, a nickel sulfate plating solution containing hypophosphite as a reducing agent is warmed to a temperature of 80 ° C., the substrate 1 is immersed in the plating solution for 60 seconds, and the Ni-P plating film 3 is formed into a transparent conductive film.
A film having a thickness of 2500 Å was formed at a predetermined position on 2. After that, the transparent conductive film 2 and the Ni-P plated film 3 are etched into a predetermined pattern with a ferric chloride mixed solution, and the Ni-P plated film 3 in an unnecessary portion is etched with nitric acid to form a substrate 1. Conductor 4 was formed.

The transparent conductive film 2 and the Ni-P plating film of this embodiment
When the adhesion strength with 3 was measured by the 90 ° peel method, it was 1.5
The adhesion strength was kg / 2 x 2 mm. This value is a practically sufficient adhesion strength. Table 1 shows the crystal grain size (Å) in the> 222 <direction and 90 ° according to the X-ray diffraction method of the substrate with a conductor made of the transparent conductive film and the Ni-P plating film in which the crystal grain size in the> 222 <direction is changed.
The results of measuring the adhesion strength (kg / 2 × 2 mm) by the peel method are shown. In the examples where the crystal grain size in the> 222 <direction was 400Å, the adhesion strength of 1.0 kg / 2 × 2 mm or less was obtained in all cases, which was not practically sufficient.

[0027]

[Table 1]

In Comparative Examples 1 to 3 of Table 1, the methods 1 to 3 for forming the three transparent conductive films described in the section of the prior art are described.
It was created by 3. In the example of Table 1, electroless Ni-P plating was described as the metal coating by the plating method, but the plating coatings of other metals also showed the same tendency as in the above embodiment depending on the type of the transparent conductive film.

[0029]

As described above, the substrate with a conductor of the present invention is a transparent conductive film containing at least one of indium oxide and tin oxide as a main component, and has a> 222 in X-ray diffraction method. Since a conductor is formed by applying a metal coating on a transparent conductive film having a crystal grain size in the <direction of 400 Å or more, a strong adhesion strength can be obtained between the transparent conductive film and the metal coating.

Further, since the transparent conductive film is formed by the vapor deposition method or the sputtering method, a large amount of polishing or etching is not required, and therefore, the phenomenon such as the disappearance of a part of the transparent conductive film or the increase of the resistance value is unlikely to occur. . In addition, a transparent conductive film having excellent productivity and uniformity of the treated surface can be obtained, and by forming a metal film on the transparent conductive film, a conductor having high reliability, uniform quality, and high productivity can be obtained. .

In the substrate with a conductor of the present invention, the metal film is formed on the transparent conductive film with a large adhesive force, so that the display portion using the transparent conductive film and another electronic circuit are connected on the same substrate. Especially when used as a circuit pattern of a so-called chip-on-glass liquid crystal display device provided with the circuit pattern of FIG.

The present invention can be applied in various ways within a range that does not impair the effects of the present invention.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of a substrate with a conductor of the present invention.

FIG. 2 is a graph showing how to determine the crystal grain size.

FIG. 3 is a graph showing how to determine a crystal grain size.

FIG. 4 is a graph showing how to determine a crystal grain size.

[Explanation of symbols]

 1: Substrate 2: Transparent conductive film 3: Ni-P plating film 4: Conductor

Claims (10)

[Claims] 1. A substrate with a conductor, wherein a metal film is formed on a required portion of a transparent conductive film of a substrate having a transparent conductive film containing at least one of indium oxide and tin oxide as a main component. A substrate with a conductor, which is a film having a crystal grain size in the> 222 <direction in the line diffraction method of 400 Å or more. 2. The substrate with a conductor according to claim 1, wherein the transparent conductive film is formed by evaporating or sputtering metallic indium or metallic tin or an alloy of indium and tin in an oxygen atmosphere at a predetermined atmospheric pressure. 3. The transparent conductive film is a transparent conductive film which is in an amorphous state immediately after vapor deposition or sputtering on the transparent conductive film forming body and is then baked into a polycrystalline state by heating. A substrate with a conductor according to claim 2. 4. The substrate with a conductor according to claim 1, wherein the transparent conductive film has a film thickness of 200Å to 2000Å. 5. The substrate with a conductor according to claim 1, wherein the metal coating is a metal plating coating. 6. The substrate with a conductor according to claim 5, wherein the metal coating is a nickel phosphorus plating coating. 7. The substrate with a conductor according to claim 1 or 5, wherein the film thickness of the metal coating is 500Å to 1 μm. 8. The substrate with a conductor according to claim 1, wherein the metal coating is a laminated coating having two or more layers. 9. The metal coating is a coating obtained by laminating another plating coating on a nickel phosphorus plating coating.
A substrate with a conductor according to the item. 10. The substrate with a conductor according to claim 9, wherein the plating film laminated on the nickel phosphorus plating film is a nickel boron metal film, a copper plating film or a gold plating film.