US 11,929,291 B2
Layer detection for high aspect ratio etch control
Gil Loewenthal, Tel-Aviv (IL); Shay Yogev, Kibbutz Kfar Menachem (IL); and Yoav Etzioni, Tel Aviv (IL)
Assigned to NOVA LTD., Rehovot (IL)
Filed by NOVA LTD., Rehovot (IL)
Filed on Aug. 23, 2021, as Appl. No. 17/445,727.
Application 17/445,727 is a continuation of application No. 16/349,287, granted, now 11,107,738, previously published as PCT/IB2017/057158, filed on Nov. 16, 2017.
Claims priority of provisional application 62/422,885, filed on Nov. 16, 2016.
Prior Publication US 2022/0044975 A1, Feb. 10, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. H01L 21/66 (2006.01); G01B 11/24 (2006.01); G01N 21/95 (2006.01); H01L 21/311 (2006.01); H01L 21/67 (2006.01); H10B 41/27 (2023.01); H10B 43/27 (2023.01)
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
OG exemplary drawing
 
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.