Test pattern layout for test photomask and method for evaluating critical dimension changes

• Main Authors: Fujita, Yuki, Levin, James P, Jeffer, Raymond W, Caldwell, Brian N, Nash, Steven C, Malenfant, Jr., Joseph L
• Format: Patent
• Language: English
• Published: 05.06.2018
• Subjects: APPARATUS SPECIALLY ADAPTED THEREFOR; BASIC ELECTRIC ELEMENTS; CALCULATING; CINEMATOGRAPHY; COMPUTING; COUNTING; ELECTRIC DIGITAL DATA PROCESSING; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; ELECTROGRAPHY; HOLOGRAPHY; MATERIALS THEREFOR; ORIGINALS THEREFOR; PHOTOGRAPHY; PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES,e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTORDEVICES; PHYSICS; SEMICONDUCTOR DEVICES

Aspects of the present invention relate to a test photomask and a method for evaluating critical dimension changes in the test photomask. Various embodiments include a test photomask. The test photomask includes a plurality of cells having a varied density pattern. The plurality of cells include a first group of cells arranged along a first line, the first group of cells having a first combined density ratio. The plurality of cells also include a second group of cells arranged along a second line, the second group of cells having a second combined density ratio. In the plurality of cells, the second combined density ratio for the second group of cells is equal to the first combined density ratio of the first group of cells. The varied density pattern is configured to substantially neutralize fogging effects.