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Proceedings Paper

Development Of Accurate Linewidth Measurement Techniques To Support Fabrication Of Devices With Structures Lum And Less
Author(s): Robert L. Van Asselt; Heinrich Becker; Edward C. Douglas
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Paper Abstract

In this study, a low voltage scanning electron microscope, a confocal beam scanning laser microscope and a bright field microscope measuring system were compared for measurement accuracy. The SEM was selected as the primary measuring system because of the higher intrinsic accuracy. Distance calibration was based on nested, coplanar pitches, and SEM cross sections with conductive coating used as dimension standards. Optical systems generally have less accuracy but display greater precision, are typically less expensive and have a higher throughput. Application of the National Bureau of Standards "Dual Threshold" technique improved the accuracy of optical bright field microscope measurements. The confocal beam scanning laser microscope displayed improved resolution compared to a bright field microscope with the same objective lens. The precise location of surfaces possible with the confocal microscope permits an extremely reproducible range of focal planes to be scanned for data acquisition. This can be used to reduce the effect of substrate variations on the measurement process, and therefore increase accuracy. The signal profiles generated by scanning the same structures with each of the three systems are compared. Problems in relating the signal profiles to the actual structures are discussed. The range of dimensions and the accuracy of each system are estimated.

Paper Details

Date Published:
PDF: 11 pages
Proc. SPIE 0921, Integrated Circuit Metrology, Inspection, and Process Control II, ; doi: 10.1117/12.968348
Show Author Affiliations
Robert L. Van Asselt, GE Microelectronics Center (United States)
Heinrich Becker, Wild Leitz USA Inc (United States)
Edward C. Douglas, GE Microelectronics Center (United States)

Published in SPIE Proceedings Vol. 0921:
Integrated Circuit Metrology, Inspection, and Process Control II
Kevin M. Monahan, Editor(s)

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