A method of etching multi-layer films, the method including: (1) etching a plurality of layers according to etching parameters, (2) determining a plurality of optical characteristics each associated with one of the plurality of layers and determined during the etching of the associated one of the plurality of layers, and (3) determining dynamic etch progressions each based on one of the plurality of optical characteristics that is associated with a particular one of the plurality of layers undergoing the etching.