Critical dimension control using development end point detection for wafers with multilayer structures

Toshiyuki Hagi; Yoshimitsu Okuda; Tohru Ohkuma

doi:10.1117/12.44436

1 July 1991 Critical dimension control using development end point detection for wafers with multilayer structures

Toshiyuki Hagi, Yoshimitsu Okuda, Tohru Ohkuma

Proceedings Volume 1464, Integrated Circuit Metrology, Inspection, and Process Control V; (1991) https://doi.org/10.1117/12.44436
Event: Microlithography, 1991, San Jose, CA, United States

Abstract

Fiber-optic-based reflectivity measurement during spray or spray/puddle development is effective for accurate critical dimension (CD) control. However, there are some difficulties in using wafers with multilayer structures. This paper describes an improved method for end-point detection of wafers with multilayer structures which consist of 160 +/- 10 nm SiN/20 nm SiO2 /Si. The improvement has been done in the following way. (1) Variation of the film thickness in the multilayer structure was found to cause shifts of the end point and CD. (2) By choosing the optimum wavelength, the CD shift was minimized for the variation of the film thickness. (3) The optimum wavelength was determined from the reflectivity measurement on the multilayer structure. (4) Improved CD accuracy of +/- 0.02 micrometers was attained for a SiN film thickness varying from -10 nm to +10 nm relative to an average value by choosing the optimum wavelength.

Citation Download Citation

Toshiyuki Hagi, Yoshimitsu Okuda, and Tohru Ohkuma "Critical dimension control using development end point detection for wafers with multilayer structures", Proc. SPIE 1464, Integrated Circuit Metrology, Inspection, and Process Control V, (1 July 1991); https://doi.org/10.1117/12.44436

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