SUBSTRATE FOR USE IN JOINING ELEMENT

摘要

A substrate for use in joining an element which comprises a base substrate of aluminum nitride or the like, a gold electrode layer formed on the surface thereof, a metal layer comprising at least one metal selected from the group consisting of Ag, Cu, Ni and Pb formed on the gold electrode layer and, formed thereon, a layer comprising a soft solder having a low melting point such as an Au−Sn type solder having a gold content of 20 wt % or less. An element having an electrode is joined by placing the element in such a manner that the electrode is contacted with the solder layer of the above substrate and then soldering by reflow at a low temperature. The above substrate allows an element to be joined to the substrate with enhanced joining strength.