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Proceedings Paper

Residual layer thickness control and metrology in jet and flash imprint lithography
Author(s): Shrawan Singhal; Ravikiran Attota; S. V. Sreenivasan
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Paper Abstract

Jet-and-Flash Imprint Lithography (J-FIL) has demonstrated capability of high-resolution patterning at low costs. For accurate pattern transfer using J-FIL, it is necessary to have control of the residual layer thickness (RLT) of cured resist underneath features. Variation in RLT leads to critical dimension variation, thereby degrading device performance. Substrate nanotopography and feature density variation are two unavoidable sources of variation in RLT uniformity. The first part of this paper demonstrates the effect of these parameters on RLT variation. Through experiments and modeling, it has been observed that flatter wafers with lower nanotopography and thinner RLT lead to better RLT uniformity. However, for studying RLT variation, accurate metrology is critical. Currently, all metrology is done using destructive cross-section scanning electron microscopy (SEM), which may not be sufficient for process control. To this end, nondestructive optics-based methods, including the Through-focus Scanning Optical Microscopy (TSOM) method have been explored in this paper. Simulations reveal the potential to measure mean RLT, RLT variation, and uncertainty in feature dimension to an accuracy of 1 nm. Experimental validation and calibration are works in progress. Subsequent development of this technique can lead to a viable in-line metrology solution for RLT underneath features.

Paper Details

Date Published: 5 April 2012
PDF: 9 pages
Proc. SPIE 8324, Metrology, Inspection, and Process Control for Microlithography XXVI, 832434 (5 April 2012);
Show Author Affiliations
Shrawan Singhal, The Univ. of Texas at Austin (United States)
Ravikiran Attota, NIST (United States)
S. V. Sreenivasan, The Univ. of Texas at Austin (United States)

Published in SPIE Proceedings Vol. 8324:
Metrology, Inspection, and Process Control for Microlithography XXVI
Alexander Starikov, Editor(s)

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