Patent ID: 9704738
Date: 2017-07-11
CPC Classifications: H01L

Claim:
1. A method, comprising: creating an etch stop trench in a top portion of a semiconductor wafer; forming a first etch stop material in the etch stop trench; producing a second etch stop material on the first etch stop material; fabricating a device layer in the top portion of the semiconductor wafer, wherein the device layer comprises an active device; bonding the semiconductor wafer to a handle wafer with the top portion of the semiconductor wafer facing the handle wafer; after the bonding, thinning a bottom side of the semiconductor wafer to a bottom portion of the first etch stop material; after the thinning, selectively eliminating the first etch stop material to a bottom portion of the second etch stop material; and after the eliminating, removing a bottom portion of the semiconductor wafer.