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, S. C. Curry, C. B. Friedberg, 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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