| 摘要 |
PROBLEM TO BE SOLVED: To join a Cu electrode or an electrode applied with Cu plating and an electrode applied with Ni/Au plating or Ag-Pd plating by soldering with high joint reliability while suppressing formation of an intermetallic compound on a joint boundary.SOLUTION: When joining a package having an electrode applied with Ni/Au plating or Ag-Pd alloy plating to a printed board having a Cu electrode or an electrode applied with Cu plating by soldering, laminated solder material for hetero electrode joint as joint material between Sn-Ag-Cu type solder material or Sn-Sb type solder material and Sn-Ag-Cu-Ni type solder material or Sn-Pb type solder material are heated or cooled, thereby, a solid phase diffusion layer is formed on an inner part of the laminated solder material for hetero electrode joint and the electrode applied with Ni/Au plating or Ag-Pd alloy plating and the Cu electrode or the electrode applied with Cu plating are joined by soldering in such a state that the Sn-Ag-Cu type solder material or the Sn-Pb type solder material is brought into contact with the Cu electrode and, at the same time, the Sn-Ag-Cu-Ni type solder material or the Sn-Cu type solder material is brought into contact with the electrode applied with Ni/Au plating or Ag-Pd alloy plating.SELECTED DRAWING: None |
