Investigation and mitigation of field-edge CDU fingerprint for ArFi lithography for 45-nm to sub-28-nm logic nodes

Autor: Le-Gratiet, Bertrand, Finders, Jo, Mouraille, Orion, Queens, Rene, Escalante, Maryana, Smeets, Bart, Beltman, Jan, Jullian, Karine
Zdroj: Proceedings of SPIE; February 2012, Vol. 8352 Issue: 1 p83520C-83520C-10, 8268491p
Abstrakt: While looking for intrafield CD variability budget definition we have observed that mask CDU correlates much better to silicon intrafield CDU when it is combined with an edge of field overexposure. This parasitic light diffusion into the field from the edge, generating a localized overexposure, is related to a mechanism called Out-Of-Field straylight. In this paper we will show evidences of this straylight mechanism, from specific experiments as well as from inline intrafield CDU analysis. In parallel we will detail specific scanner and masks tests that are being done attempting to quantify and understand this phenomenon. During this first characterisation phase we have also seen that this signature is quite systematic from a scanner to another and could be somehow modulated by the mask itself (transmission and absorber type). Today straylight is modelled in our APC as a unique contribution added to the mask and further investigations are needed to fully characterize it.
Databáze: Supplemental Index