Coating film, method for forming coating film, and light-emitting diode device

Abstract

[Problem] To form, on a surface of a metallic material, a coating film which can prevent the surface of a metallic material from being discolored by corrosion due to any heat treatment during production or even due to outdoor use over a long period, and which has excellent wire bonding properties. [Solution] A hexamethyldisiloxane compound is sprayed together with nitrogen gas serving as a carrier gas under atmospheric pressure in a nitrogen plasma gas to convert the hexamethyldisiloxane compound to radicals, thereby polymerizing the compound. Thus, a polysiloxane film which has a thickness of 4-14 nm and which is constituted of a polysiloxane, the main chain of which is -(Si-O-Si)n-, is formed on a surface of a metallic material.

Description

technical field [0001] The present invention relates to a coating film formed on the surface of a metal material, especially silver or silver alloy, a method for forming the coating film, and a light emitting diode device provided with the coating film. Background technique [0002] Connectors and lead frames, which are connection parts for electronic devices, are often used in which copper and nickel base plating is applied to the surface of copper alloy materials such as brass and phosphor bronze, and silver plating is performed thereon. Since silver is a good conductor of electricity and heat, it is widely used as a plating material for connectors and lead frames. However, there is a problem that silver is easily discolored in the air, and especially corroded in an environment containing sulfur, discoloration becomes dark brown or blue-black, and electrical contact deteriorates. [0003] In recent years, from the viewpoint of energy saving and environmental protection, t...

AI Technical Summary

Problems solved by technology

However, there are the following problems: silver is easy to change color in the air, especially when it is corroded in an environment containing sulfur, the color becomes dark brown or blue-black, and the electrical contact becomes poor.

However, the thickness of the coating layer formed by this technique is about 300nm, so applying this technique to the coating film of the reflective part of the LED device has problems in terms of wire bonding characteristics

In addition, in this technique, since the plasmaization of the gas and the activation of the atomized spray coating forming material are performed at the same time, the activation of the spray coating forming material becomes uneven, and it is difficult to cover the entire surface of the substrate without omission. form a dense coating

In particular, when there is a passivation film on the surface of the metal material to be coated, or when a noble metal is used as the metal material, the above-mentioned surface state is inactive and in a low-energy state, so the coating film composed of organic substances is formed without omission. is extremely difficult

Therefore, even if an extremely thin coating film can be formed on the surface of a metal coating such as silver by this technology, there may be problems in appearance such as uneven treatment and dirt caused by the surface.

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