Patent ID: 9018735
Filing Date: 2015-04-28
Classification: H01L

Abstract:
1. A silicon wafer, comprising: a first denuded zone formed with a depth ranging from approximately 20 μm to approximately 80 μm from a top surface of the silicon wafer; and a bulk area formed between the first denuded zone and a backside of the silicon wafer, the bulk area having a concentration of oxygen within a range from approximately 10.5 to approximately 13 ppma (parts per million atom) uniformly distributed within a variation of 10% over the bulk area, and a density of bulk micro defect in the bulk area being greater than or equal to 5.43×10 wherein the first denuded zone is a defect free zone; the first denuded zone and the bulk area are obtained by performing a first rapid thermal process and a second rapid thermal process after the first rapid thermal process, a size of oxygen precipitate in the bulk area increasing during the second rapid thermal process, and by performing a first annealing process at a first temperature, and a second annealing process at a second temperature subsequent to the first annealing process, the second temperature being higher than the first temperature; and the first rapid thermal process and the second rapid thermal process are performed at a temperature in a range of approximately 950° C. to 1150° C.