Method for fabricating phase shifting mask and a phase shifting mask

Abstract

The method for fabricating a phase-shifting mask includes the steps of providing a substrate having a light shielding layer and a phase-shifting light transmitting layer sequentially formed thereon, first patterning the light shielding layer and the phase-shifting light-transmitting layer to form phase-shifting regions, and oxidizing sidewall portions of the light shielding layer in each phase-shifting region to form phase-shifting light-transmitting sidewall portions. The method further includes the steps of depositing photoresist over the substrate, second patterning the photoresist using the light shielding layer as a mask such that in each phase-shifting region a portion of the phase-shifting light-transmitting layer on the light shielding layer is exposed by removal of the photoresist, and forming a rim phase-shifting layer in each phase-shifting region using the photoresist pattern as a mask. The rim phase-shifting layer includes unexposed portions of the phase-shifting light-transmitting layer and the phase-shifting light transmitting sidewall portions. Then, a half-tone layer in each phase-shifting region is formed using the photoresist pattern as a mask such that a rim phase-shifting layer surrounds each half-tone layer.

Dependencies are inferred from the claim text.