Method of manufacturing semiconductor device

A method of manufacturing a semiconductor device which includes a first member and a second member joined to the first member, the method comprising:

• a) producing (Cu,Ni)6Sn5 on a Ni film formed on the first member by melting a first unit of Sn—Cu solder containing 0.9 wt % or higher of Cu on the Ni film of the first member;
• b) producing (Cu,Ni)6Sn5 on a Ni film formed on the second member by melting a second unit of Sn—Cu solder containing 0.9 wt % or higher of Cu on the Ni film of the second member, the second unit of Sn—Cu solder being physically separated from the first unit of Sn—Cu solder;
• and
• c) after the steps a) and b) have been completed so that (i) the (Cu,Ni)6Sn5 has been produced from the first unit of Sn—Cu solder on the Ni film of the first member and (ii) the (Cu,Ni)6Sn5 has been produced from the second unit of Sn—Cu solder on the Ni film of the second member, and the second unit of Sn—Cu solder still is physically separated from the first unit of Sn—Cu solder, joining the first member and the second member to each other by melting the first unit of Sn—Cu solder having undergone step a) and by melting the second unit of Sn—Cu solder having undergone step b) so that the first unit of Sn—Cu solder and the second unit of Sn—Cu solder become integrated into a single unit.