Patent ID: 8257546

Claim:
A method for monitoring an etch process, comprising: (a) performing pre-etch critical dimension (CD) measurements of a substrate to generate pre-etch measurement information; (b) applying an outlier filter to remove outliers in the pre-etch measurement information; (c) analyzing the pre-etch measurement information to determine that a patterning is of a sufficient quality to allow for etching of the substrate and to determine process parameters to an etch process; (d) providing the substrate along with the pre-etch measurement information to an etch reactor; (e) etching the substrate in the etch reactor to form structures in the substrate using the etch process, wherein the pre-etch measurement information in combination with etch process monitoring are used to in-situ monitor an etch process endpoint, wherein the etch process monitoring comprises: directing radiation onto the substrate, wherein an intensity of the radiation is modulated at a frequency of about 10 Hz; and collecting a portion of the radiation reflected from the substrate to determine critical dimension of the structures formed in the substrate; and (f) terminating the etch process based on the etch process monitoring having identified that the etch process has reached the etch process endpoint.