Patent ID: 9568872
Date: 2017-02-14
CPC Classifications: G01B,G01N,G03F,G03G,H01L

Claim:
1. A method of controlling a manufacturing process, the method comprising the steps of: a) providing a testing area with a periodic structure having a period d, wherein within each period d the periodic structure includes a plurality of alternating lines having constant width and spaces having monotonically increasing width and wherein the periodic structure includes a series of sets of patterned features; b) illuminating the periodic structure with a light, thereby producing a plurality of non-zero order diffraction signals, c) collecting the diffraction signals to produce a test signature; d) matching the test signature with a reference signature, wherein the reference signature was previously produced by performing steps a), b), and c) with respect to a reference structure; and e) controlling a manufacturing process using a control setting set associated with the matching reference signature.