PURPOSE: To satisfy sufficiently the heat dissipation property and thermal fatigue property of a semiconductor element and to prevent inclusion of bubbles in solder and a junction failure from being generated by a method wherein the solder consists of a specified composition containing antimony, silver and copper in addition to the main component consisting of one or both of tin and lead, and moreover, contains a specified amount of phosphorus.

CONSTITUTION: A solder for die bonding use consists of a composition containing 1 to 10wt.% of antimony, 0.5 to 6wt.% of silver and 1wt.% of copper in addition to the main component consisting of one or of tin lead, and moreover, contains 0.01wt.% to less than 1.0wt.% of phosphorus. In a semiconductor device, which is mounted with the solder of such a composition and is completed via prescribed processes, inclusion of bubbles in the solder is little, a good heat resistance value is obtained and there is also no variation.