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Proceedings Paper

Ablation and cleaning of wafer surface by excimer laser
Author(s): Yong-Kee Kim; Dae-Jin Kim; Je-Kil Ryu; Sung-Sik Pak
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Paper Abstract

The importance of surface cleaning is an essential factor in VLSI technology, flat panel display, and data storage devices. The results of laser cleaning technology were studied using KrF excimer laser (248 nm) irradiation in cleanroom environment. The applied energy density was 200 - 800 mJ/cm2 at a repetition rate of 10 - 40 Hz with various focused beam widths. Results of photoresist stripping were made before and after laser irradiation with PR covered wafers and comparison of laser cleaning results were investigated as well with bare wafers. The atomic force microscopy (AFM) images of laser cleaning results were also presented and compared before and after laser irradiation. The surface roughness of AFM image of contaminated wafer surface before laser irradiation was 192 angstrom and that of after laser irradiation was 16.2 angstrom. The mechanism of laser cleaning and ablation is rapid thermal expansion of substrate surface induced by an instantaneous temperature rising due to laser irradiation. It is found that the temperature rising of the substrate surface was about 297 degree(s)C with a fluence of 400 mJ/cm2 at 300K. Laser dry cleaning technology easily removed fingerprints, submicron Al2O3 and SiO2 particulates intentionally contaminated on the top of the wafer surface without aids of toxic chemicals and deionized water.

Paper Details

Date Published: 29 June 2001
PDF: 9 pages
Proc. SPIE 4274, Laser Applications in Microelectronic and Optoelectronic Manufacturing VI, (29 June 2001); doi: 10.1117/12.432546
Show Author Affiliations
Yong-Kee Kim, Hantech Co., Ltd. (South Korea)
Dae-Jin Kim, Hantech Co., Ltd. (South Korea)
Je-Kil Ryu, Hantech Co., Ltd. (South Korea)
Sung-Sik Pak, Hantech Co., Ltd. (South Korea)

Published in SPIE Proceedings Vol. 4274:
Laser Applications in Microelectronic and Optoelectronic Manufacturing VI
Malcolm C. Gower; Henry Helvajian; Koji Sugioka; Jan J. Dubowski, Editor(s)

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