| 摘要 |
<p>PURPOSE:To relieve thermal strain generated during heat treatment by a method wherein on a back surface of an insulating single crystal substrate which is utilized during fabrication of an SOS structured semiconductor device, a layer which is composed of a material which has nearly equal thermal expansion coefficient as a semiconductor layer on a front surface and less hardness than the substrate is formed. CONSTITUTION:On a back surface of a sapphire substrate 1, a single crystal Si layer 2 is deposited utilizing vapor phase deposition, and a back side reinforcement is applied on the substrate 1. Next thereto on the surface of the substrate 1 a single crystal Si layer 3 on which elements are to be formed is grown by vapor phase deposition in the same way. Next thereto in the layer 3 plural number of MOS integrated circuits 41, 42 etc. are formed, being isolated by a scribing lise 5 utilizing conventional method. Next thereto they are covered by a protective film such as wax etc., and utilizing mixture of fluoric and nitric acid the layer 2 which was used as a reinforcement and now becomes useless is etched away and the substrate 1 is divided into a piece of circuit after cutting it by a diamond stylus along a scribing line. By this method deterioration of circuits can not occur in spite of heat treatment during a process.</p> |
