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13 May 1994 Overlay measurement and analysis of x-ray/optical lithography for mix-and-match device applications
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A joint Motorola/IBM experiment was performed in mix-and-match lithography across widely separated locations. A simple pattern placement metrology data set was created, and x-ray masks were manufactured according to this data. The same data was converted into a 5x reticle and optically stepped on wafers. The x-ray mask was designed to print upon two optical fields with one x-ray exposure. The x-ray mask was aligned to the wafers to produce box-in- box images for overlay metrology. The main overlay problems encountered were systematic offsets between x-ray and optical images, and average magnification error of approximately 8 ppm. The magnification error is substantial because of the 3 degree(s)C temperature difference between the optical stepper stage and the x-ray mask-writer. In an actual device run, the magnification differences will be removed by compensation in the e-beam writing of the x-ray mask. Offsets will be removed by use of a send-ahead wafer to determine the correct offset alignment in the x-ray stepper.
© (1994) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Arnold W. Yanof, Kevin D. Cummings, Philip A. Seese, Matthew A. Thompson, Mark Drew Jr., Daniel J. DeMay, James M. Oberschmidt, Robert H. Fair, and Angela C. Lamberti "Overlay measurement and analysis of x-ray/optical lithography for mix-and-match device applications", Proc. SPIE 2194, Electron-Beam, X-Ray, and Ion-Beam Submicrometer Lithographies for Manufacturing IV, (13 May 1994);

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