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No.44 2011.12

The influence of component of sintering aids in Ag paste on electroless Ni/Au Plating Process

General Head Research Yuki Tsuno
General Head Research Yuki Nagao

Low-melting point glass is used for sintering aids” bonding agent “of conductive paste or LTCC boards etc. In the low-melting point glass, lead-free glass is mainly employed by environmental regulation of RoHS Directive etc. Therefore, we have developed various lead-free glasses by classifying them into bismuth, zinc and silica types for difference of frameworks. And, Ni/Au plating is often performed in order to get excellent solder bonding ability and excellent gold wire bonding ability on electrodes formed by silver paste to which low-melting point glass of lead-free was added as sintering aids. Plating-resistance of the silver electrodes is required.

In this paper, we describe results that investigated elution composition and elution volume from low-melting point glass of lead-free that is sintering aids, state of silver film and plating resistance.

Laminated Structure for LED Lighting System "TOP MRS PROCESS"

General Head Research Tomomi Aoki

Light Emitting Diode, namely” LED “has great advantages, for example, long life, high luminous efficiency, conservation and more. It’s the reason that LED attracts rising attentions as light sources in the future. Silver plating is excellent in light reflectivity. So it’s widely applied to reflectors for LED elemental devices. However, silver is naturally tarnished with ease. The lower reflectivity after a long-term use is a great apprehension in the industry.

In our research, we find that the debasement in reflectivity ascribes to the” internal “and “external “factors: the former means copper diffusion from copper-alloy materials and the latter indicates the sulfuration of silver film.

We’ve developed” TOP MRS PROCESS “, which can wonderfully maintain the light reflectivity for LED reflectors for a long time. It’s composed of two processes, firstly” TOP MRS-PD “as palladium plating to prevent copper-diffusion, then” TOP MRS-ZN “as zinc oxide film on bright silver plating for anti-sulfuration.

Formaldehyde-free Type Electroless Copper Plating Solution "OPC COPPER AF"

General Head Research KANG JOONHAENG

In recent years, decrease and restriction of use of environmental load substance have been promoted by legal regulation such as WEEE, RoHS directive or REACH.

As for electroless copper plating process, formaldehyde is widely used as a reducing agent because it is low cost and accessible. Formaldehyde is recognized as a carcinogen in recent years because of low vaper pressure and strong stimulation even if it is low concentration. It may become subject of regulation in future because adverse effect to environment or human body is large.

On this background, we have worked on the development of electroless copper plating solution without formaldehyde. As a result, we have developed electroless copper plating process, “ OPC COPPER AF “which uses sodium hypophosphite as a reducing agent.