| 摘要 |
PURPOSE:To enable a stable-quality substrate for LSI to be formed with a good yield, by using a specific silicon substrate and then performing heat treatment at both 600-900 deg.C and 1000-1200 deg.C for the substrate respectively once or more. CONSTITUTION:A silicon substrate to be used is the one whose ratio alpha1106/alpha513 of absorption factors alpha1106 to alpha513 at room temperature for infrared light of 1106 cm<-1> and 513cm<-1> in wave numbers is 4.0 or more. Heat treatments both at 600-900 deg.C and 1000-1200 deg.C for the substrate are performed respectively once or more before or during an element formation process. Time for which the heat treatment at 600-900 deg.C is performed is 4 hours or more. An atmospere in which the heat treatment performed at 1000-1200 deg.C is non-oxidizing or reducing. Time for which the heat treatment at 1000-1200 deg.C is performed is 4 hours or more. Hence, the stable-quality substrate for LSI can be formed with a good yield.
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