Method of forming a phase shift mask

Abstract

The present invention relates to a method of forming a phase shift mask on a mask substrate. This method comprises sequentially forming a phase shifter layer and a shield layer on the mask substrate, forming a photo-resist layer on a predetermined region of the shield layer, wherein the periphery of the photo-resist layer comprises at least one vertical side-wall, and forming a deposition layer uniformly on the photo-resist layer and the shield layer surrounding the photo-resist layer. Next, silylanizing the deposition layer. Next, performing an anisotropic etching process to remove the deposition layer on top of the photo-resist layer and the shield layer surrounding the photo-resist layer, and to partially remove the deposition layer covered on the vertical side-wall of the photo-resist layer so as to form a spacer on the vertical side-wall of the photo-resist layer. Then, vertically removing the shield layer and the phase shifter layer not covered by the photo-resist layer and the spacer, and vertically removing the spacer and the shield layer under the spacer. Lastly, removing the photo-resist layer completely to complete the phase shift mask.

Dependencies are inferred from the claim text.