US 6,887,627 B2 · Method of fabricating phase shift mask

Abstract

A method of fabricating a phase shift mask (PSM) is described. A patterned photoresist layer is formed on an opaque layer over a transparent plate. A thin mask layer is formed on the sidewalls of the patterned photoresist layer. The exposed opaque layer and transparent plate thereunder are then removed while using the patterned photoresist layer and mask layer as a mask. A phase shift opening is formed in the transparent plate, and thereby a phase shift layer is formed at the place where the phase shift opening is located. The patterned photoresist layer and the opaque layer thereunder are then removed to expose the transparent plate. The opaque layer under the mask layer can precisely self-align the phase shift layer to prevent alignment deviation caused by multiple lithography processes. The precision of the phase shift mask can be increased, and mask manufacture cost can be lowered.

Claims18

Dependent claims

A method of fabricating a phase shift mask, comprising the steps of:

forming an opaque layer and a patterned photoresist layer sequentially on a transparent plate;
forming a mask layer over said opaque layer and said patterned photoresist layer;
removing a portion of said mask layer to leave a portion of said mask layer on sidewalls of said patterned photoresist layer and to expose said opaque layer;
removing an exposed portion of said opaque layer and a portion of said transparent plate thereunder to form a phase shift opening;
and
removing said patterned photoresist layer and a portion of said opaque layer under said patterned photoresist layer.

3 more elements

Dependencies are inferred from the claim text.

Method of fabricating phase shift mask

Life of this patent

Method of fabricating phase shift mask

Life of this patent

Abstract

Claims18