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Proceedings Paper

Mechanism studies of scanning electron microscope measurement effects on 193-nm photoresists and the development of improved line-width measurement methods
Author(s): T. R. Sarrubi; Matthew F. Ross; Mark Neisser; Thomas Kocab; Bernard T. Beauchemin Jr.; William R. Livesay; Selmer S. Wong; Waiman Ng
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Paper Abstract

The effect of scanning electron microscope (SEM) measurements on the dimensions of resist features was studied for 193nm resist materials. Initial measurements showed that resist lines became smaller as they were repeatedly measured, with size changes of up to 40 to 50 nm after 50 to a 100 measurements. There was a significant size change for the two 193nm resist systems tested, an acrylate based single layer system and a hybrid single layer system, although the magnitude of the effect was different for each system. The total dose per SEM measurement seen locally by the resist was calculated to be on the order of 100 (mu) C/cm$_2), a significant amount by the standards of e-beam induced chemistry. Entire wafers of the hybrid system were cured in an e-beam curing system to enable chemical characterization of irradiated resist. It was found that there was loss of the anhydride functionality when blanket-coated wafers of the hybrid system were cured and a corresponding reduction in film thickness. The remaining material was cross-linked. However, to our surprise, we found that e-beam curing of exposed line and space patterns id not result in any critical dimension (CD) change, any height change, or any profile change. What is more, the cured line and spaces patterns did not show significant line width change when repeatedly measured in a SEM. It is speculated that the resists gets hot while being measured and how hot affects how much shrinkage is seen. Depending on the temperature reached, either cross-linking or annealing will be the fastest process; and the balance between the two will determine how much shrinkage is seen during measurement.

Paper Details

Date Published: 24 August 2001
PDF: 11 pages
Proc. SPIE 4345, Advances in Resist Technology and Processing XVIII, (24 August 2001); doi: 10.1117/12.436837
Show Author Affiliations
T. R. Sarrubi, Arch Chemicals, Inc. (United States)
Matthew F. Ross, Electron Vision Corp. (United States)
Mark Neisser, Arch Chemicals, Inc. (United States)
Thomas Kocab, Arch Chemicals, Inc. (United States)
Bernard T. Beauchemin Jr., Arch Chemicals, Inc. (United States)
William R. Livesay, Electron Vision Corp. (United States)
Selmer S. Wong, Rockwell Science Ctr. (United States)
Waiman Ng, KLA-Tencor Corp. (United States)

Published in SPIE Proceedings Vol. 4345:
Advances in Resist Technology and Processing XVIII
Francis M. Houlihan, Editor(s)

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