Power limits for non-destructive laser ablation of contaminants on micromachined structures

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The minimum and maximum laser irradiances that are effective in cleaning etch-released membranes and microstructure was measured for carbon microparticles on LPCVD silicon nitride thin films and suspended platforms. A 1064nm Nd:Yag laser was scanned across the samples to ablate the contaminants. Microscope images of the membranes showed mass removal for an irradiance as low as 600W cm-2. More thorough cleaning was achieved by increasing the irradiance. For 2.5×2.5mm, 205nm thin silicon nitride membranes, 79% of the contaminated area was removed with an exposure of 3.7kW cm-2. Catastrophic damage was seen at a power level of 8.4kW cm-2. Ablation effects were also measured as a change in optical absorption using a photo thermal common-path interferometer. Peak absorption values were decreased from over 100,000ppm to less than 20,000ppm. Silicon nitride platforms were also tested. Despite significant substrate heating, the platforms survived intact up to power levels of 8.4kW cm-2 with near perfect cleaning of carbon particles from their surfaces.

Original languageEnglish (US)
Title of host publication2016 International Conference on Optical MEMS and Nanophotonics, OMN 2016 - Proceedings
PublisherIEEE Computer Society
ISBN (Electronic)9781509010356
DOIs
StatePublished - Sep 13 2016
Event21st International Conference on Optical MEMS and Nanophotonics, OMN 2016 - Singapore, Singapore
Duration: Jul 31 2016Aug 4 2016

Publication series

NameInternational Conference on Optical MEMS and Nanophotonics
Volume2016-September
ISSN (Print)2160-5033
ISSN (Electronic)2160-5041

Other

Other21st International Conference on Optical MEMS and Nanophotonics, OMN 2016
CountrySingapore
CitySingapore
Period7/31/168/4/16

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