Electronic circuit device and method of producing the same

Abstract

In connecting an electronic circuit part such as a semiconductor or other part to a substrate for mounting the part with solder, the solder is composed of a high-melting-point solder portion which is subjected to working such as rolling and heat treatment in order to break the cast structure thereof, and a smaller volume of low-melting-point solder portions. The high-melting-point solder portion is connected to both the electronic circuit substrate and the electronic circuit part through the low-point-melting solder portions. This method enables interconnection between objects to be connected without impairing the high ductility and toughness of the high-melting-point solder which is subjected to working and heat treatment. This soldering method ensures highly reliable manufacture of miniaturized high density circuits, such as LSI.

Dependencies are inferred from the claim text.