Barbara A Peck

US Patent:

53007867, Apr 5, 1994

Filed:

Oct 28, 1992

Appl. No.:

7/967885

Inventors:

Timothy A. Brunner - Ridgefield CT
Michael S. Hibbs - Westford VT
Barbara B. Peck - Westford VT
Chrisopher A. Spence - Westford VT

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G01N 2186

US Classification:

250548

Abstract:

A photolithography mask structure having a novel optical focus test pattern is described. The mask structure has a non-phase-shifted, transparent substrate and includes a phase shifter of other than 180. degree. disposed between spaced, parallel opposing lines such that an alternating pattern of non-phase-shifted material and phase-shifted material is defined transverse said parallel lines. When projected onto the surface of an object measurable shifts of the test pattern corresponds in direction and magnitude with the extent of system defocus. Various alternating test pattern embodiments are presented, all of which include at least one phase shift window of other than 180. degree. in relation to the mask substrate. Further, a monitoring system and a monitoring process are discussed employing the presented mask structures.