| 摘要 |
PURPOSE:To prevent the generation of the reaction grain boundary of Sn as well as to contrive improvement in thermal fatigue characteristics by microscopically forming Pb crystals by a method wherein the title solder is formed with Pb as the main component and Ag or Sb, and Cu or As are added to the remainder of Sn. CONSTITUTION:The solder to be used for semiconductor, on which thermal fatigue characteristics are improved, is formed by adding Ag or Sb and Cu, with which Pb crystals are microscopically formed, or As of 0.05-0.1wt% to the main component of Pb. The reason why the quantity of addition of Ag or Sb, Cu or As is set at 0.05-0.1wt. is that the characteristics of thermal fatigue can not be improved sufficiently when the quantity of addition is less than 0.05wt% and that the thermal fatigue characteristics are deteriorated when the quantity of addition exceeds 0.1% on the contrary to the above. The deterioration of the thermal fatigue characteristics generated when the quantity of addition exceeded 0.1wt% is considered that it is resulted from the generation of the instable state of alloy due to the difference in density and also due to the presence of an intermetallic compound, because the intermetallic compound such as Cu6Sn5, Ag3Sn and SbSn is formed by Cu, Ag, Sb and Sn. |
