公开(公告)号：EP1048392A4

公开(公告)日：2002-04-17

申请号：EP98959137

申请日：1998-12-09

Applicant: HITACHI LTD

Inventor： SHIMOKAWA HANAE ,  SOGA TASAO ,  OKUDAIRA HIROAKI ,  ISHIDA TOSHIHARU ,  NAKATSUKA TETSUYA ,  INABA YOSHIHARU ,  NISHIMURA ASAO

IPC: B23K1/00 ,  B23K35/00 ,  B23K35/26 ,  C22C13/02 ,  H01L23/50 ,  H05K3/34 ,  B23K1/20

CPC classification number: H05K1/181 ,  B23K1/0016 ,  B23K35/004 ,  B23K35/007 ,  B23K35/262 ,  B23K2201/40 ,  H01L23/488 ,  H01L23/49811 ,  H01L23/532 ,  H01L24/29 ,  H01L2224/83101 ,  H01L2924/01322 ,  H01L2924/15747 ,  H05K3/3426 ,  H05K3/3463 ,  H05K2201/10909 ,  Y02P70/613 ,  Y10T29/49144 ,  Y10T29/49149 ,  Y10T29/49169 ,  Y10T428/12708 ,  Y10T428/12715 ,  H01L2924/00

Abstract: A Pb-free solder-connected structure having a sufficiently large connection strength, featuring an interface that remains stable even after the passage of time, and maintaining sufficient wettability and resistance against whiskers, and an electronic device. Specifically, a Pb-free solder, characterized in that an Sn-Ag-Bi solder which is a representative Pb-free solder is connected to an electrode that has an Sn-Bi layer formed on the surface thereof. Bi concentration in the Sb-Bi layer is preferably 1 to 20 % by weight to obtain a sufficient degree of wettability. When a more reliable joint is required, the Cu layer is formed under the Sn-Bi layer to obtain a connection portion having a sufficiently large interfacial strength.