Paper
22 August 2001 Improving the measurement algorithm for alignment
Shinichi Nakajima, Yuho Kanaya, Akira Takahashi, Koji Yoshida, Hideo Mizutani
Author Affiliations +
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.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Shinichi Nakajima, Yuho Kanaya, Akira Takahashi, Koji Yoshida, and Hideo Mizutani "Improving the measurement algorithm for alignment", Proc. SPIE 4344, Metrology, Inspection, and Process Control for Microlithography XV, (22 August 2001); https://doi.org/10.1117/12.436780
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CITATIONS
Cited by 3 scholarly publications.
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KEYWORDS
Optical alignment

Overlay metrology

Signal detection

Detection and tracking algorithms

Image processing

Semiconducting wafers

Microscopes

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