| 摘要 |
PURPOSE:To prevent a wafer from warpage and to eliminate an automatic doping during a wafer processing by forming a laminated protective film of SiO2 and Si3N4 initially on the back surface of the wafer processing, thereby balancing stresses irrespective of the state of the back surface. CONSTITUTION:Two wafers 1 in which the front surface is formed in a mirror state and the back surface is formed with relatively ruggedness are matched on the mirror surfaces and are intimately contacted, and a set of two wafers are filled in a treating furnace which contains O2 of high moisture while exposing the back surfaces. Then, the furnace is pressurized to treat the wafers at 1,000 deg.C for approx 1hr, thereby producing a thick SiO2 film 2 having a thickness of 2- 3mum, the wafers are then removed from the furnace, and an Si3N4 film 4 having a thickness of approx. 0.5-1mum is accumulated by a gas phase growth method on the film 2. Thereafter, the set of the wafers are isolated, and when an SiO2 film 3 of approx. 1,000Angstrom is formed on the surface upon formation of the film 2, this film is removed, a buried layer 5 is diffused and formed on the surface of the wafer 1, an epitaxial layer 6 is grown, the layer 6 is then insularly formed with a field SiO2 film 7, and an element 8 is formed thereon. |
