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Proceedings Paper

Improving the measurement algorithm for alignment
Author(s): Shinichi Nakajima; Yuho Kanaya; Akira Takahashi; Koji Yoshida; Hideo Mizutani
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Paper Abstract

As semiconductor design rules decrease, tighter tolerances are required for alignment. Improvement of the measurement algorithm can make a considerable contribution to reduction of the overlay error. An algorithm makes the alignment accuracy greatly improved that utilizes wavelet transform and uses information about image asymmetry. Experimental result using the Alignment Data Logging System shows that there is a process that the algorithm reduces the overlay error from over 100nm (3(sigma) ) to under 50nm. Two other algorithms are also introduced that are an interpolation method that reduces error from image sampling and a mark recognition method that reduces measurement failures focusing on some kinds of symmetry of the alignment mark.

Paper Details

Date Published: 22 August 2001
PDF: 11 pages
Proc. SPIE 4344, Metrology, Inspection, and Process Control for Microlithography XV, (22 August 2001); doi: 10.1117/12.436780
Show Author Affiliations
Shinichi Nakajima, Nikon Corp. (Japan)
Yuho Kanaya, Nikon Corp. (Japan)
Akira Takahashi, Nikon Corp. (Japan)
Koji Yoshida, Nikon Corp. (Japan)
Hideo Mizutani, Nikon Corp. (Japan)

Published in SPIE Proceedings Vol. 4344:
Metrology, Inspection, and Process Control for Microlithography XV
Neal T. Sullivan, Editor(s)

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