| 摘要 |
PURPOSE:To inhibit the generation in vicinity of the surface of a defect based on heat treatment stably by forming a polycrystal silicon film on the back of a wafer, thermally treating the wafer in a nonacidic atmosphere and thermally treating a silicon nitride film on the back of the wafer under a deposited condition. CONSTITUTION:The pole Si film 44 is shaped on the back of the Si wafer 41 within the range of 200-1,000nm through a CVD method (film forming temperature is 600-900 deg.C) utilizing the pyrolysis of SH4. The wafer 41 is warped so that the surface side is concaved by compressive stress in the film 44. The compressive stress in the film 44 is changed into tensile stress by thermally treating the wafer for time such as approximately one hour at a temperature such as 1,100 deg.C in the nonacidic atmosphere of Ar, etc., and the wafer is warped so that the surface side is convexed. When the wafer is thermally treated for approximately one hour in the wet O2 of 1,100 deg.C and a thermal oxide film 46 is shaped, the generation of the defects based on heat treatment are concentrated in a region extending over the back direction from the central section of the wafer by the action of a sink and a stress gradient, and a non-defect condition is obtained in the vicinity of the surface. |
