13 September 1982 Wafer Stepper Characterization And Process Control Techniques
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A process control vehicle is described which allows the characterization and comparison of wafer steppers with respect to distortion, resolution, uniformity, and misregistration. A block of test structures consisting of optical resolution patterns, verniers, and electrical line width and misalignment resistors is arrayed on an 11 x 11 grid which fills the entire available field of a 10X reticle. Fach block also contains a pair of targets for the THE laser-interferometric auto-alignment system. The ability of the auto-aligner to acquire such targets to within 500 is exploited as a metrology tool whereby the measured coordinates at each site are compared to the ideal (theoretical) coordinates to generate a vector distortion map across the field. Subsequent reduction of misregistration data is accomplished via application of the six parameter model developed by Perloff and co-workers. It is shown that these diagnostic tools permit the rapid characterization of distortion anisotropy for a given stepper and can be used to optimize and monitor level-to-level regis-tration. Further applications are suggested.
© (1982) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
S. C. Curry, C. B. Friedberg, "Wafer Stepper Characterization And Process Control Techniques", Proc. SPIE 0334, Optical Microlithography I: Technology for the Mid-1980s, (13 September 1982); doi: 10.1117/12.933566; https://doi.org/10.1117/12.933566

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