CPC H01L 22/26 (2013.01) [G01B 11/24 (2013.01); G01N 21/9501 (2013.01); H01L 21/31111 (2013.01); H01L 21/67253 (2013.01); G01B 2210/56 (2013.01); H10B 41/27 (2023.02); H10B 43/27 (2023.02)] | 9 Claims |
1. A metrology system for controlling an etch process applied by an etch apparatus to a multi-layered structure, the metrology system comprises:
an optical profile monitor that is configured to (a) illuminate a region of interest of the multi-layered structure during an etch process applied to the multi-layered structure; and (b) measure a spectral reflectance of the region of interest of the multi-layered structure;
an etch layer detector that is configured to (a) calculate a spectral derivative of a spectral reflectance signal obtained from the measuring; (b) identify, in the spectral derivative, a discontinuity indicative of a of crossing a layer boundary of the multi-layered structure; and
a controller that is configured to (a) determine that the layer boundary corresponds to a preselected layer boundary of the multi-layered structure; and (b) generate control signals for applying a predefined control action to the etch process responsive to determining that the crossed layer boundary corresponds to the preselected layer boundary of the multi-layered structure.
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