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Proceedings Paper

Threshold measurements in laser-assisted particle removal
Author(s): Shyan Jer Lee; Kamran Imen; Susan Davis Allen
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Paper Abstract

Laser assisted particle removal (LAPR) is a novel technique capable of removing particulate contamination from solid surfaces. LAPR uses an energy transfer medium which preferentially absorbs into capillary spaces under and around the particles on the contaminated substrate. Laser irradiation causes explosive evaporation of the energy transfer medium via absorption into the energy transfer medium itself or the substrate/particle system with subsequent conductive heat transfer. The explosive force propels particles off the substrate much like a small rocket engine. In our experiments, LAPR was used to remove 9.5 micrometers Al2O3, 5 micrometers Al2O3, and 1 micrometers polystyrene particles from Si surfaces at the wavelengths of 10.6 micrometers and 9.6 micrometers using water as the energy transfer medium. At these wavelengths the laser energy is absorbed predominantly in the water. Laser removal thresholds (J/cm2) were obtained using a degenerate threshold model. The temperature rise in the energy transfer medium was estimated, suggesting that superheating of the absorbed water is a reasonable mechanism for LAPR.

Paper Details

Date Published: 1 December 1991
PDF: 11 pages
Proc. SPIE 1598, Lasers in Microelectronic Manufacturing, (1 December 1991); doi: 10.1117/12.51020
Show Author Affiliations
Shyan Jer Lee, Univ. of Iowa (United States)
Kamran Imen, Univ. of Iowa (United States)
Susan Davis Allen, Univ. of Iowa (United States)

Published in SPIE Proceedings Vol. 1598:
Lasers in Microelectronic Manufacturing
Bodil Braren, Editor(s)

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