Kla-tencor Technologies Corporation

Kla Corporation

Pei-Chun Chiang

Jun Ye

Mark Joseph Wihl

Weston L Sousa

Lih-Huah Yiin

George Q Chen

Wenfei Gu

Methods and systems for detecting defects on a mask are provided. One method includes generating a database reference image for a multi-die mask by simulation and detecting first defects on the mask by comparing the database reference image to images of the mask generated by an imaging subsystem for a first of the multiple dies. The method also includes generating a die reference image for the first of the multiple dies by applying one or more parameters of the imaging subsystem learned by generating the database reference image to the images generated by the imaging subsystem of one or more of the multiple dies other than the first multiple die. In addition, the method includes detecting second defects on the mask by comparing the die reference image to the images of the mask generated by the imaging subsystem for the first of the multiple dies.

Defect detection for multi-die masks

Techniques that use the design databases used in each of the expose/etch steps during construction of phase shift masks are described. A model or reference image is rendered, accounting for systematic variations, from the design databases to represent what a layer of the PSM should look like after processing. The reference image is compared to an optically acquired image of a specimen phase shift mask to find defects. The technique of the present invention can be used to inspect EAPSM, APSM and tritone masks. The technique inspects all layers in one pass and is therefore more efficient.

Multiple design database layer inspection

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Cupertino, CA, United States of America

Pei-Chun Chiang