| 摘要 |
PURPOSE: To obtain high quality with high yield by a method wherein, when semiconductor multilayer material having a top silicon layer is manufactured, a silicon wafer containing boron whose concentration is higher than or equal to a specific value is heat-treated in an hydrogen atmosphere at a specific temperature or higher, baron is diffused outward, its concentration is decreased, and the top layer is subjected to a thinning process. CONSTITUTION: Two CZ silicon wafers of a top 11 and a base 12 are prepared, and the top wafer 11 is made to contain boron whose concentration is 10<19> /cm<3> or higher. The wafers 11, 12 are subjected to a thermal oxidation process in a dry oxidizing atmosphere in a temperature range of 850-1000 deg.C, for 10-60 minutes. Thermal oxide layers 13, 14 of 5-100μm are formed on the surfaces of the respective wafers. The thermal oxide layers 13, 14 are collectively heat- trated for joining in an Ar atmosphere at 800-1100 deg.C, for 10-60 minutes. After bonding, the wafer of the top 11 is mechanically polished to be 7-15μm thick. The wafer is heated at 1000-1200 deg.C in a hydrogen atmospher, for 10-1000 minutes. Boron is diffused outward and a low concentration layer 11a is obtained. Thereby high quality is obtained with high yield.
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