Patent ID: 7033518

Claim:
A method of continuously etching a multi-layer film, comprising the steps of: storing a target etch depth for each layer of a plurality of layers of said multi-layer film; determining the value of a selected optical characteristic for an initial layer of said plurality of layers; etching a layer of said plurality of layers according to selected etching parameters, said etching of each layer further comprising; (a) determining a plurality of values for said selected optical characteristic associated with each one of said plurality of layers-undergoing said etching, (b) calculating in real time the dynamic etch progressions based on said plurality of values associated with said layer undergoing said etching, (c) determining if one of said dynamic etch progressions is the same as said target etch depth for said layer undergoing said etching, and (d) repeating steps (b) and (c) until said target etch depth and said dynamic etch progressions are the same; determining the value of a selected optical characteristic for another layer of said plurality of layers; and repeating said etching step for said another layer.