Haynes and Boone, LLP
Extreme ultraviolet lithography with reduced exposure dose and negative tone development
A method of lithography patterning includes forming a resist layer over a substrate and providing a radiation with a first exposure dose to define an opening to be formed in the resist layer. The opening is to have a target critical dimension CD1 after developed by a negativ-tone development (NTD) process. The method further includes exposing the resist layer to the radiation with a second exposure dose less than the first exposure dose and developing the resist layer in a negative-tone development process to remove unexposed portions of the resist layer, resulting in an opening between resist patterns. A critical dimension CD2 of the opening is greater than CD1 by a delta. The method further includes forming an interfacial layer on sidewalls of the resist patterns. The interfacial layer has a thickness that is substantially equal to half of the delta.
TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD.
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Chen-Yu Ching-Yu
Liu Chang