Patent ID: 8193084

Claim:
A method of manufacturing a semiconductor device, comprising: providing a semiconductor substrate comprising a first insulation film formed on a main surface of the semiconductor substrate; forming a first wiring on the first insulation film; forming an opening in the semiconductor substrate from a back surface of the semiconductor substrate so as to expose the first insulation film, the opening having a first end at the main surface and a second end at the back surface; forming a second insulation film in the opening and on the back surface; forming a second wiring on the second insulation film so that the second wiring is connected to the first wiring at the first end and extends from inside the opening and beyond the second end to cover a portion of the back surface; forming a continuous solder layer on the back surface so as to be in contact with the second wiring extending beyond the second end and so as to enter the opening to cover only a portion of the second wiring on a sidewall and also a portion of the second wiring on a bottom of the opening; and reflowing the solder layer so that a portion of the solder layer flows into the opening, whereby the solder layer is formed on the back surface so that a portion of the solder layer is in contact with the second wiring at the first end of the opening prior to the reflowing.