Patent ID: 8785265

Claim:
A method for manufacturing a semiconductor device, comprising the steps of: forming an insulating film containing nitrogen over a substrate including an insulating surface; introducing the substrate over which the insulating film containing nitrogen is formed, into a vacuum chamber; forming a first oxide semiconductor film containing nitrogen by sputtering in a nitrogen containing atmosphere under a first deposition condition that the substrate temperature is higher than or equal to 150° C. and lower than or equal to 450° C.; forming a second oxide semiconductor film containing nitrogen by sputtering in a nitrogen containing atmosphere under a second deposition condition that the substrate temperature is higher than or equal to 150° C. and lower than or equal to 450° C.; and performing heat treatment at a temperature higher than or equal to 150° C. and lower than or equal to 650° C. after the deposition is performed under the second deposition condition, wherein the first oxide semiconductor film to which the heat treatment is performed has a wurtzite crystal structure.