Sub-resolution phase shift mask

U.S. Patent Number: 5698349

Abstract: The invention describes the fabrication and use of a sub-resolution phase shift mask. The mask is formed using a single alignment step with all other alignment steps being accomplished by self alignment. This self alignment is made possible by using vertical anisotropic etching of an opaque material layer to form opaque spacers at the pattern edges of phase shifting material. The opaque spacers combine with phase shifting and other opaque regions of the mask to provide improved image resolution and depth of focus tolerance at the surface of an integrated circuit wafer.

Inventors: Yang; Ming-Tzong (Hsin Chu, TW)

Assignee: United Microelectronics Corporation (Hsin-Chu City, TW)

Application Number: 08/670,271

Issued: 1997-12-16

Expired: 2005-12-16

Classes: 430/5 ; 430/313

Field of search: 430/5,322,324,313

Click the image above to view patent images at uspto.gov within a frame.

Click here for the fulltext page on uspto.gov within a frame.