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Proceedings Paper

The effect of UPW quality on photolithography defect
Author(s): Wah Hoo Ng; Siew Ing Yet; Chu Yaw Liau
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Paper Abstract

Photolithography resist process consists of priming, resist coating, post-apply bake, exposure, post-exposure bake develop, and post bake; advanced RETs and immersion photolithography has more critical resist process steps. Materials used in the resist process require the utmost in cleanliness, especially coating & develop process. In photolithography, De-Ionized Water (DIW) or Ultra Pure Water (UPW) is used during resist developing process as the pre-wet and rinsing material. UPW is supplied by a centralized auto supply system in a semiconductor fabrication; the UPW is controlled for temperature, pH, resistivity, TOC, ions, and etc. State of the art semiconductor design continues to shrink; defect control becomes essential for high yields in semiconductor fabrication. In this paper, effect of UPW quality on resist process defect is revealed. Low resistivity DIW used in resist developing process generates residue defects, which created killing block etch defect after the subsequent etching process. Different measurements for DIW quality are demonstrated; water pH, conductivity, and Total Organic Carbon (TOC) in this case reflected the quality issue of UPW. Detail study on the residue defect and the cause-and-effect with UPW's quality is shown and discussed; the hypothesis is explained with experimental results. High quality UPW is required to eliminate the residue defect, hence minimal defective wafer is obtained. Additionally, resist developing process optimization to improve process robustness is also important.

Paper Details

Date Published: 14 December 2009
PDF: 7 pages
Proc. SPIE 7520, Lithography Asia 2009, 75202V (14 December 2009); doi: 10.1117/12.836992
Show Author Affiliations
Wah Hoo Ng, X-FAB Sarawak Sdn. Bhd. (Malaysia)
Siew Ing Yet, X-FAB Sarawak Sdn. Bhd. (Malaysia)
Chu Yaw Liau, X-FAB Sarawak Sdn. Bhd. (Malaysia)

Published in SPIE Proceedings Vol. 7520:
Lithography Asia 2009
Alek C. Chen; Woo-Sung Han; Burn J. Lin; Anthony Yen, Editor(s)

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