Glass wafers and automatic defect inspection equipment are being used successfully to do reticle image qualification. This technique assures that a reticle is free of repeating defects prior to being used to expose silicon wafers on a wafer stepper. The task becomes more essential, and more difficult as geometry sizes break the 1 micron barrier and relevant defect sizes approach 0.35 micron. In this study, the printibality of defects on glass wafers is examined and defect size is compared to the same defects printed in resist on silicon. Glass wafers are then inspected on a KLA 209. The concepts of defect fidelity function and effective defect capture size are defined and experimentally validated for wet and dry etched chrome and aluminum clad glass wafers. Undercutting is also examined for the four cases.
James A. Reynolds,
David B. Fundakowski,
"Defect Fidelity On Chrome And Aluminum Coated Glass Wafers.", Proc. SPIE 0772, Optical Microlithography VI, (1 January 1987); doi: 10.1117/12.967060; https://doi.org/10.1117/12.967060