26 March 1993 Alignment technique for second-level exposure of phase-shifting masks using 10-kV raster-scan electron-beam lithography system
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Abstract
The fabrication of phase shifting masks requires precise alignment between the primary and shifter layers. The MEBESR IV electron-beam lithography system uses its SEM mode to acquire a video image of the phase shift mask (PSM) alignment mark. Digital signal- processing algorithms have been developed to accurately determine the locations of the marks. Alignment marks are acquired through various resist systems and film thicknesses. Machine control software translates and rotates the MEBES coordinate system to align it with the mask coordinate system, as determined by the location of the alignment marks. Results showing overlay accuracy between layers are presented.
© (1993) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Frank E. Abboud, Jorge L. Freyer, Andrew J. Muray, Robert J. Naber, John T. Poreda, John R. Thomas, "Alignment technique for second-level exposure of phase-shifting masks using 10-kV raster-scan electron-beam lithography system", Proc. SPIE 1809, 12th Annual BACUS Symposium on Photomask Technology and Management, (26 March 1993); doi: 10.1117/12.142148; https://doi.org/10.1117/12.142148
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