Patent ID: 9535334
Date: 2017-01-03
CPC Classifications: G03F

Claim:
1. A method for extreme ultraviolet lithography (EUVL) process, comprising: loading a binary phase mask (BPM) to a lithography system, wherein the BPM includes two phase states and defines an integrated circuit (IC) pattern thereon, wherein the BPM includes a first phase state of the two phase states at a greater occurrence than a second phase state of the two phase states; setting an illuminator of the lithography system in an illumination mode according to the IC pattern; providing EUV light from the illuminator in the illumination mode to the BPM; reflecting the EUV light from the BPM configuring a pupil filter in the lithography system according to the illumination mode; using the pupil filter, filtering out a non-diffracted component of the reflected EUV light from the first state and the second state, wherein an average amplitude of the filtered non-diffracted component is substantially near an amplitude of EUV light reflected from the first state; increasing an amplitude of a diffracted component of the reflective EUV light, wherein the amplitude of the reflected EUV light diffracted from the second state is approximately doubled after the filtering; and exposing a photoresist layer with the diffracted component having the increased amplitude.