| 摘要 |
PURPOSE:To prevent deterioration of characteristic and occurrence of damage of semiconductor elements caused by thermal distortion, by extending the thermal expansion material in the thermal melting process of soldering material. CONSTITUTION:The thermal expansion material 11 is composed of shape memory alloy coated with foaming resin which foams by heating and electrically insulative resin. This thermal expansion material 11 is temporarily fixed by an adhesive agent between the upper surface of the wiring substrate 1 and the lower surface of the semiconductor element 5, and the soldering material is melted by heating in the furnace. In this manner, the electrode 7 of the semiconductor 5 is electrically connected to the wiring substrate 1. When the soldering material is melted by heating, the semiconductor element 5 extends in the direction of (a) on account of the difference of the thermal distribution and the thermal expansion coefficient between the wiring substrate 1 and the semiconductor element 5. In accordance with cooling, the semiconductor element 5 contracts in the direction of (b). After hardening of the soldering material 4, the strength to supress the contraction of the semiconductor element 5 decreases, so that the thermal distortion remaining in the semiconductor element 5 can be absorbed by the soldering material 4 which has extended. |
