7 November 1983 Wafer Pattern Defect Detection: An Automatic Inspection Technique
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A system to automatically inspect wafers for pattern defects has recently been developed. With this apparatus, the patterns of two neighboring chips are converted into video signals, which are then electronically compared by sophisticated hybrid circuitry to determine any differences between them. The discrepancies, if any, are recognized as defects. The inspection results are processed with a built-in microcomputer and the defect coordinates are stored in memory. By accessing them, the wafer is moved into exact position for post-inspection confirmation and close examination of each defect by the operator through a microscope. The defective wafer pattern is also displayed on a video monitor. In addition, it is possible to draw a defect map by utilizing an X-Y plotter interfaced to the inspection system. The system is equipped with two inspection modes for maximum versatility. The video signal can be generated by either bright-field or dark-field imaging methods. The user may therefore select the mode most compatible to a specific wafer and its requirements. Typical applications of this system include: - to detect pattern defects on the finished wafer (after photoresist developing an e, etching) that may have occured during the various production processes. - to detect repeating defects resulting from inconsistencies on an arrayed reticle used in the wafer stepping process. (The importance of this feature will become increas-ingly evident as direct wafer steppers become the workhorses of the VLSI era.) - to monitor various processing factors, such as foreign particle contamination. The performance and efficiency of such an automatic wafer inspection system will undoubtedly lead to its replacing the current conventional method of manual microscopic examination by the human eye in the near future. This is supported by the inclusion of data collected by end users of this system.
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Yasushi Uchiyama, Yasushi Uchiyama, Daikichi Awamura, Daikichi Awamura, Katsuyoshi Nakashima, Katsuyoshi Nakashima, } "Wafer Pattern Defect Detection: An Automatic Inspection Technique", Proc. SPIE 0394, Optical Microlithography II: Technology for the 1980s, (7 November 1983); doi: 10.1117/12.935144; https://doi.org/10.1117/12.935144


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