| 摘要 |
PURPOSE:To reduce a stress caused at the inside of an IC chip by a method wherein a porous polytetrafluoroethylene layer is formed between a semiconductor element and a base material. CONSTITUTION:A porous polytetrafluoroethylene layer 5 in laid between a base body 3 and a semiconductor element 1. The layer 5 is preferably made by stretching polytetrafluoroethylene film and make it porous. The member can be obtained properly when fine hole gaps at 2mum or lower are formed at a porosity of 40 to 95%, especially at 60 to 80%. Thereby, when the layer 5 whose Young's modulus is low is used, the stretch of the base material 3 is absorbed by the layer 5 when a temperature is raised. Thereby, a large stress is not caused on both the surface and the rear surface of the element 1. In the same manner, when the temperature is lowered, the contraction of the base material 3 is transmitted to the element 1 after it has been reduced largely, and a chip is not damaged. |
