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Proceedings Paper

High-resolution profilometry for improved overlay measurements of CMP-processed layers
Author(s): Anna Mathai; Jason Schneir
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Paper Abstract

Chemical-mechanical polishing (CMP) processes are widely used in the semiconductor industry to enable multilevel device processing and smaller device features with smaller stepper lens depth of focus. However, CMP planarization of the wafers can lead to failure modes in stepper alignment and overlay measurements that rely on some topography for contrast. It is also been speculated that the CMP process, with its rotating pads that are wetted with polishing slurry, has a spreading or smearing effect on the overlay targets. Both these effects can lead to inaccurate and imprecise overlay measurements. In this paper, we present the results of measuring the depth and asymmetry of overlay targets post-CMP using a High Resolution Profiler. We find clear evidence of smearing in post-CMP overlay targets and discuss its impact on stepper registration error.

Paper Details

Date Published: 8 June 1998
PDF: 10 pages
Proc. SPIE 3332, Metrology, Inspection, and Process Control for Microlithography XII, (8 June 1998); doi: 10.1117/12.308725
Show Author Affiliations
Anna Mathai, KLA-Tencor Corp. (United States)
Jason Schneir, KLA-Tencor Corp. (United States)


Published in SPIE Proceedings Vol. 3332:
Metrology, Inspection, and Process Control for Microlithography XII
Bhanwar Singh, Editor(s)

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