| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a soldering method for doing a die-bonding superior in heat resistance for a semiconductor chip such as transistors, IC, etc., especially, power transistors under easy temperature control. <P>SOLUTION: A solder having a Pb content of 75% or more and a sold-liquid phase line temperature difference of 20°C or higher is heated into a solid-liquid coexisting state to solder the interface in this state. The solder having the Pb content of 75% or more itself has a high heat resistance to heat cycles and, if the soldering temperature varies somewhat, surely can hold the solid-light coexistence state, this allowing a solder layer to be easily thick owing to a solid solution in the solid-liquid coexisting material. Thus the shearing strain γ applied to the solider layer under heat cycles, based on the difference between linear thermal expansion coefficients of works, is easily reduced and the heat resistance of the solder itself may be increased to satisfactorily prevent the breakdown (crack breakdown) of the solder layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
