Bryan M Barnes

US Patent:

7772710, Aug 10, 2010

Filed:

Oct 31, 2007

Appl. No.:

11/931140

Inventors:

Richard Silver - Derwood MD, US
Pete Lipscomb - Cedar Park TX, US
Bryan Barnes - Derwood MD, US

Assignee:

Sematech, Inc. - Austin TX
National Institute of Standards and Technology - Gaithersburg MD

International Classification:

H01L 23/544

US Classification:

257797, 257283, 257E2154, 257E23179, 438401, 438462, 356401, 356400

Abstract:

A zero-order overlay target comprises a first zero-order line array fabricated on a first layer of a semiconductor structure, the first zero-order line array having a first pitch, and a second zero-order line array fabricated on a second layer of the semiconductor structure, the second zero-order line array having a second pitch. The second pitch may be different from the first pitch, and a portion of the second zero-order line array may be positioned to become optically coupled to a portion of the first zero-order line array when subject to an overlay measurement. Further, the second pitch may be variable. For example, the variable pitch may comprise a first set of features having a pitch approximately equal to the first pitch, a second set of features having a pitch different from the first pitch, and a third set of features having a pitch approximately equal to the first pitch.