International Business Machines Corporation

Barbara Bates Peck

Michael Straight Hibbs

Timothy A Brunner

Grant N Pealer, Iii

Dean Craig Humphrey

Chrisopher A Spence

The invention relates to the evaluation of the pupil illumination profile in a projection lithography system using an imaging reticle featuring a plurality of holes of few microns in diameter. The imaging reticle is placed at the lens object plane and a photoresist coated substrate is exposed in a defocused position from the lithographic image plane. The image reticle has a plurality of identical holes that are regularly spaced at predetermined distances for a more detailed evaluation of the effective pupil illumination across the entire exposure field.

Pupil imaging reticle for photo steppers

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.

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Westford, VT, United States of America

Barbara Bates Peck