Patent ID: 7846792

Claim:
A method for manufacturing a semiconductor device, comprising: (a) forming first insulating layers as buffer layers over front and back sides of a semiconductor substrate; (b) forming second insulating layers and third insulating layers over the first insulating layers in this order, the second insulating layers having different etching characteristics from the third insulating layers; (c) measuring a thickness of one of the second insulating layers; (d) removing the front side third insulating layer by etching and removing part of the front side second insulating layer by etching, the etch depth of the front side second insulating layer depending on the thickness of the second insulating layer measured in step (c); (e) patterning the remaining front side second insulating layer and etching the semiconductor substrate using the patterned front side second insulating layer as a mask to form a device isolation trench; (f) depositing a device isolation insulating film so as to fill the device isolation trench with a device isolation insulating layer and removing part of the device isolation insulating layer formed over the front side second insulating layer by polishing using the front side second insulating layer as a stopper; and (g) removing the front side second insulating layer by etching.