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The demands of submicron VHSIC Technology are trending to + .10 pm critical dimension control and + .10 μm overlay control. Equipment such as that evaluated in this paper will take an increasing role in this environment because it offers precision in the .002 μm range 1 a, moreover it produces the required data base in a reasonable time. The electrical prober provides alignment and linewidth data from specialized test structures etched into conductive films. This can provide a wealth of information about the photo/etch process. Again, it must be emphasized that the data collection process is highly automated and, therefore, very objective. In this paper, summaries of evaluations performed on various types of lithographic equipment available to us are presented. Processes used to generate the test structures are shown. Applications of the modeling capabilities when applied to the lithographic equipment are also included. This system can be very useful, for example, when applied to a projection 1:1 scanning system. One can model for translation and rotation error, commonly induced by operator misalignment, and thereby separate it from typical equipment related problems, i.e., scan, crosscan. The system will also model lens distortions and stepping errors from data accumulated with step-and-repeat equipment. Vector mapping of misregistration and contour mapping of linewidth variation gives one a powerful tool for seeing his own process capabilities. Comparison testing of the electrical prober to other linewidth measuring equipment, including optical and SEM, will also be reviewed. This is very important as linewidth measurement is fundamental to the electrical prober's operation. Optical systems for linewidth measurement and verniers placed directly on product provide a fine front line in baselining a process, particularly because of their immediate feedback of good data (bad sources notwithstanding). But, the process engineer using the electrical prober will realize a data base that truly enables him to make definitive statements about his own process as more stringent device requirements present themselves.
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