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Proceedings Paper

Bottom anti-reflective coatings: fluid property characterization and wetting tendency
Author(s): Owen J. Hehmeyer; Abhishek Singh; Ramkumar Subramanian; Joffre Bernard
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Paper Abstract

This series of studies focuses on the fundamental fluid properties of several commercially available bottom anti- reflective coatings (BARCs). A goniometer was used to complete pendant drop analysis and dynamic contact angle measurement for two similar varieties (A-1 and A-2) of a 248nm BARC and another, competing variety (B-1) of a 248nm BARC. The pendant drop analysis shows that the liquid surface tension of the three BARCs is identical. The contact angle analysis was performed on SiON, low k dielectric, and F-based oxide type layers. Contact angle analysis shows that B-1 wets the least quickly, A-1 wets the most rapidly, and A-2 wets at an intermediate rate. All three wet quickly, A-1 and A-2 completely wet the surface, and B-1 nearly does. The surface type does not seem to affect the wetting rate, despite a real difference in the chemistry of the surface, as shown by the different surface energies of the materials. A Newman-type polymer-spreading model is proposed for the BARC spreading and shown to offer reasonable explanation of the wetting process. Three wafers, one for each BARC, were coated with resist and BARC and then stripped. The stripping process appears to have no major effect on the SiON and F- based oxide surfaces. However, the stripping process modifies the low k dielectric surface in an unknown way, making it more hydrophilic, which causes A-1 and A-2 BARCs to spread less well. Three wafers, one for each BARC, were subjected to a 20 degree(s)C/minute bake over the temperature range 50-220 degree(s)C in a mass spectrometer. The analysis shows that A-1 BARC exhibits the most outgassing, that A-2 BARC exhibits an intermediate level of outgassing and that the B-1 exhibits the least level of outgassing. In general, the B-1 peaked at substantially lower levels. The analysis shows that water vapor forms the largest component of the evolved gas. A-1 BARC causes the most water outgassing. The A-2 BARC, being substantially more viscous than the A-1 BARC, coats much thicker. The thickness is related to the spin speed by an inverse power relationship, where the power is -0.419.

Paper Details

Date Published: 24 July 2002
PDF: 13 pages
Proc. SPIE 4690, Advances in Resist Technology and Processing XIX, (24 July 2002); doi: 10.1117/12.474181
Show Author Affiliations
Owen J. Hehmeyer, Advanced Micro Devices, Inc. (United States)
Abhishek Singh, Advanced Micro Devices, Inc. (United States)
Ramkumar Subramanian, Advanced Micro Devices, Inc. (United States)
Joffre Bernard, Advanced Micro Devices, Inc. (United States)

Published in SPIE Proceedings Vol. 4690:
Advances in Resist Technology and Processing XIX
Theodore H. Fedynyshyn, Editor(s)

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