The patterning of the contact layer is modulated by strong etch effects that are highly dependent on the geometry of the contacts. Such litho-etch biases need to be corrected to ensure a good pattern fidelity. But aggressive designs contain complex shapes that can hardly be compensated with etch bias table and are difficult to characterize with standard CD metrology. In this work we propose to implement a model based etch compensation method able to deal with any contact configuration. With the help of SEM contours, it was possible to get reliable 2D measurements particularly helpful to calibrate the etch model. The selections of calibration structures was optimized in combination with model form to achieve an overall errRMS of 3nm allowing the implementation of the model in production.

Date Published: 20 October 2016
PDF: 8 pages
Proc. SPIE 10032, 32nd European Mask and Lithography Conference, 1003202 (20 October 2016); doi: 10.1117/12.2248013

Published in SPIE Proceedings Vol. 10032:
32nd European Mask and Lithography Conference
Uwe F.W. Behringer; Jo Finders, Editor(s)