Mask overlay scaling error caused by exposure energy using a stepper

Takashi Saito; Shin-ya Sakamoto; Keiji Okuma; Hirofumi Fukumoto; Yoshimitsu Okuda

doi:10.1117/12.148970

4 August 1993 Mask overlay scaling error caused by exposure energy using a stepper

Takashi Saito, Shin-ya Sakamoto, Keiji Okuma, Hirofumi Fukumoto, Yoshimitsu Okuda

Proceedings Volume 1926, Integrated Circuit Metrology, Inspection, and Process Control VII; (1993) https://doi.org/10.1117/12.148970
Event: SPIE'S 1993 Symposium on Microlithography, 1993, San Jose, CA, United States

Abstract

The wafer expansion scaling error in overlay accuracy using a stepper has been investigated. The scaling error depends on the exposure energy, mask aperture ratio and wafer surface reflectance. The scaling error is observed only along the X axis when using a global alignment method. From the experimental results, we present a mechanism which explains the scaling error. Then the occurrence of the scaling error according to the mechanism is simulated by the heat conduction and displacement analysis. The cause of the scaling error is proved to be local wafer expansion due to the accumulated heat generated by the exposure light energy.

Citation Download Citation

Takashi Saito, Shin-ya Sakamoto, Keiji Okuma, Hirofumi Fukumoto, and Yoshimitsu Okuda "Mask overlay scaling error caused by exposure energy using a stepper", Proc. SPIE 1926, Integrated Circuit Metrology, Inspection, and Process Control VII, (4 August 1993); https://doi.org/10.1117/12.148970

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