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Proceedings Paper

Distortion compensation for accurate overlay in lithography of quasiperiodic patterns
Author(s): Babak H. Khalaj; Yagyensh C. Pati; Thomas Kailath
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Paper Abstract

In this paper, we address the problem of ensuring accurate overlay in lithography of patterned substrates with low-order distortions. This problem becomes more important in situations where warpage and thermally induced distortion of high-density quasi-periodic patterns in large flat panel displays (FPDs), or high-density memory cells demand appropriate compensation schemes. A recently developed signal processing technique is used to estimate and compensate for substrate distortion. While avoiding time-consuming (e.g. site-by-site) alignment procedures, the proposed technique permits the use of time-efficient alignment procedures (e.g. global alignment) without compromising overlay accuracy. The proposed technique first estimates the existing low-order distortion of the patterned substrate. After estimating the distortion, global alignment schemes can be used to align the image of next layer to the previous one in a few check points. In the final step, the estimated distortion function can be used for compensating the local misalignments.

Paper Details

Date Published: 22 May 1995
PDF: 6 pages
Proc. SPIE 2439, Integrated Circuit Metrology, Inspection, and Process Control IX, (22 May 1995); doi: 10.1117/12.209211
Show Author Affiliations
Babak H. Khalaj, Stanford Univ. (United States)
Yagyensh C. Pati, Stanford Univ. (United States)
Thomas Kailath, Stanford Univ. (United States)

Published in SPIE Proceedings Vol. 2439:
Integrated Circuit Metrology, Inspection, and Process Control IX
Marylyn Hoy Bennett, Editor(s)

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