Patent ID: 8273644

Claim:
A soldering method of soldering a cooling base member made of a first metal material to a second member, the method comprising the steps of: forming a solder resist region composed of an oxide film of the first metal material of the cooling base member at at least one part of an outer peripheral portion surrounding a soldering-target region of the cooling base member by selectively shooting a laser light to the at least one part of the outer peripheral portion surrounding the soldering-target region of the cooling base member to thermally oxidize a surface of the cooling base member and form the oxide film of the first metal material; and bonding the second member to the soldering-target region of the cooling base member using a solder, wherein the oxide film has a strongly oxidized region and a weakly oxidized region, wherein the strongly oxidized region is positioned bordering the soldering-target region so that the strongly oxidized region is in contact with the soldering-target region.