| 摘要 |
PURPOSE:To achieve insulating performance and thermal expansion characteristic similar to those of alumina and to improve the heat radiation performance and the machinability, by providing an insulating layer composed of alumina onto the surface of Al-Si alloy having the thermal expansion coefficient lower than a specific value. CONSTITUTION:Al-Si alloy having the thermal expansion coefficient lower than 16X10<-6>/ deg.C is employed for the base of a substrate 1, and an insulating layer 2 composed of alumina is provided on the surface portion of said base requiring insulating property. Since insulating property and thermal expansion characteristic similar to those of conventional alumina substrate are provided and Al-Si alloy is employed for the base of the substrate, high heat conductivity is achieved thereby the heat radiation performance is improved and high speed thermal recording is realized. Furthermore, since the thermal expansion coefficient is close to that of IC being mounted or thin film, the thin film will not be peeled off through heat cycle, and since the alumina insulating layer is compatible with Al-Si alloy of base, it can be adhered strongly to the surface of said Al-Si alloy. |
