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Proceedings Paper

Scatterometry measurement of nested lines, dual space, and rectangular contact CD on phase-shift masks
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Paper Abstract

Evaluation of lithography process or stepper involves very large quantity of CD measurements and measurement time. In this paper, we report on a application of Scatterometry based metrology for evaluation of binary photomask lithography. Measurements were made on mask level with ODP scatterometer then on wafer with CD-SEM. 4 to 1 scaling from mask to wafer means 60nm line on wafer translates to 240nm on mask, easily measurable on ODP. Calculation of scatterometer profile information was performed by a in-situ library-based analysis (5sec/site). We characterized the CD uniformity, linearity, and metal film thickness uniformity. Results show that linearity measured from fixed-pitch, varying line/space ratio targets show good correlation to top-down CD-SEM with R2 of more than 0.99. ODP-SEM correlation results for variable pitch shows that careful examination of scatterometer profile results in order to obtain better correlation to CD SEM, since both tools react differently to the target profile variation. ODP results show that global CD distribution is clearly measurable with less outliers compared to CD SEM data. This is thought to be due to 'averaging' effect of scatterometer. The data show that Scatterometry provides a nondestructive and faster mean of characterizing lithography stepper performanceprofiles. APSM 1st level (before Cr removal) 'dual-space' CDs and EPSM rectangular contacts were also measured with and results demonstrates that Scatterometer is capable of measuring these targets with reasonable correlation to SEM.

Paper Details

Date Published: 5 April 2007
PDF: 6 pages
Proc. SPIE 6518, Metrology, Inspection, and Process Control for Microlithography XXI, 651856 (5 April 2007); doi: 10.1117/12.729246
Show Author Affiliations
Kyung M. Lee, Intel Corp. (United States)
Sanjay Yedur, Timbre Technologies, Inc. (United States)
Sven Henrichs, Intel Corp. (United States)
Malahat Tavassoli, Intel Corp. (United States)
Kiho Baik, Intel Corp. (United States)

Published in SPIE Proceedings Vol. 6518:
Metrology, Inspection, and Process Control for Microlithography XXI
Chas N. Archie, Editor(s)

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