Patent ID: 7144749

Claim:
A method of etching a semiconductor device having a fuse embedded therein beneath different first and second sets of material, comprising: (a) first etching at least a first set of material from a first region of the semiconductor device, from the surface of the first set of material in towards the embedded fuse; (b) measuring the remaining distance between the embedded fuse and the first etched surface of the first region of the semiconductor device; (c) second etching an amount of the second set of material from said first region of the semiconductor device, from the first etched surface of the first region further in towards the embedded fuse, the amount of the second set of material being determined based on the preceding measurement of the remaining distance; (d) measuring the remaining distance between the embedded fuse and the second etched surface of the first region of the semiconductor device; and (e) determining if the remaining distance measured in step (d) falls within a desired range of distances and, if the remaining distance does not fall within the desired range, returning to step (c).