| 摘要 |
A Sn-Ag-Cu based lead-free solder ball having a chemical composition, in mass %, that Ag: 1.0 to 4.0 %, Cu: 0.05 to 2.0 %, P: 0.0005 to 0.005 % and the balance: Sn. When used for forming a solder bump on the electrode of BGA or CSP, the above lead-free solder ball is free from the yellow discoloration (yellowing) of its surface, exhibits excellent wettability, and also is free from the formation of voids in a portion connected with the solder. The lead-free solder ball is specifically effective for a fine solder ball having a diameter of 0. 04 to 0.5 mm. |
