Power semiconductor device and manufacturing method therefor
View Patent ↗A power semiconductor device includes a substrate, an element circuit pattern formed on the substrate and made of Cu covered with an electroless Ni—P plating layer, and a power semiconductor element bonded to the element circuit pattern by a solder, wherein the solder is an alloy of Sn, Sb, and Cu, and the weight percent of Cu is in the range of 0.5 to 1%, inclusive.
1. A power semiconductor device comprising:
a substrate;
an element circuit pattern formed on said substrate and made of Cu covered with an electroless Ni—P plating layer; and
a power semiconductor element bonded to said element circuit pattern by a solder;
wherein said solder is an alloy of Sn, Sb, and Cu, and the weight percent of Cu is in the range of 0.5 to 1%, inclusive.
2. The power semiconductor device according to claim 1 , wherein the weight percent of Sn in said alloy is in the range of 91 to 93%, inclusive, and the weight percent of Sb in said alloy is in the range of 6.5 to 8%, inclusive.
3. The power semiconductor device according to claim 2 , further comprising:
a terminal circuit pattern formed on said substrate; and
a terminal bonded to said terminal circuit pattern by a terminal solder;
wherein said terminal solder is an Sn—Ag-based or Sn—Ag—Cu-based unleaded solder having a liquidus temperature in the range of 215° to 220° C., inclusive; and
wherein said solder has a solidus temperature in the range of 235° to 238° C., inclusive.
4. The power semiconductor device according to claim 1 , wherein said Ni—P plating layer has a thickness in the range of 2 to 3 μm, inclusive.
5. A power semiconductor device comprising:
a substrate;
a circuit pattern which is an unplated Cu pattern formed on said substrate;
a power semiconductor element bonded to said circuit pattern by a solder made of an alloy of Sn, Sb, and Cu;
a terminal circuit pattern formed on said substrate;
a terminal bonded to said terminal circuit pattern by a terminal solder made of an Sn—Ag-based or Sn—Ag—Cu-based unleaded solder;
wherein the weight percent of Cu in said solder is in the range of 0.5 to 1%, inclusive, and said solder has a solidus temperature in the range of 235° to 238° C., inclusive; and
wherein said terminal solder has a liquidus temperature in the range of 215° to 220° C., inclusive.
6. The power semiconductor device according to claim 5 , further comprising:
a bottom surface pattern formed on the surface of said substrate opposite that on which said circuit pattern is formed; and
a heat sink bonded to said bottom surface pattern by a solder having the same composition as said solder;
wherein said heat sink is Cu and is not plated.