1. Silicon Nitride Circuit Board for Power Modules
While past practice has been to use alumina and aluminum nitride for the insulated substrate used in the power modules of automobiles, new forms of energy, industrial equipment, and other such applications, silicon nitride substrates are increasingly being adopted because of their excellent material strength, thermal conductivity, and insulation.
In the past, commercial-scale production of silicon nitride substrates by Hitachi Metals, Ltd. has largely been of the insulated substrates themselves. Recently, however, Hitachi Metals has embarked on the full-scale production of silicon nitride substrates for power modules that are composed of a silicon nitride insulated substrate brazed to copper sheet.
Hitachi Metals already has the materials used in a silicon nitride circuit board (the silicon nitride substrate and the brazing material and copper sheet), and is able to satisfy a wide variety of customer requirements. A newly developed silicon nitride substrate with high thermal conductivity (130 W/m•K) is also available.
There is a trend toward the use of thicker copper (0.6 mm or more) to enhance the heat dissipation of circuit boards for power modules. Hitachi Metals has come up with a wide product range to coincide with silicon nitride circuit boards for power modules entering full-scale production. Hitachi Metals has also started to offer surface treatment of copper circuit in the form of plating with nickel (Ni), silver (Ag), etc., and the intention is to expand the options for material characteristics, copper thickness, and copper circuit patterns in the future.
(Hitachi Metals, Ltd.)