Microencapsulation of silicon cavities using a pulsed excimer laser

Sherif M. Sedky, Hani H. Tawfik, Mohamed Ashour, Andrew B. Graham, John W. Provine, Qingxiao Wang, Xixiang Zhang, Roger T. Howe

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

This work presents a novel low thermal-budget technique for sealing micromachined cavities in silicon. Cavities are sealed without deposition, similar to the silicon surface-migration sealing process. In contrast to the 1100°C furnace anneal required for the migration process, the proposed technique uses short excimer laser pulses (24ns), focused onto an area of 23mm 2, to locally heat the top few microns of the substrate, while the bulk substrate remains near ambient temperature. The treatment can be applied to selected regions of the substrate, without the need for special surface treatments or a controlled environment. This work investigates the effect of varying the laser pulse energy from 400 mJ cm 2to 800 mJ cm 2, the pulse rate from 1Hz to 50Hz and the pulse count from 200 to 3000 pulses on sealing microfabricated cavities in silicon. An analytical model for the effect of holes on the surface temperature distribution is derived, which shows that much higher temperatures can be achieved by increasing the hole density. A mechanism for sealing the cavities is proposed, which indicates how complete sealing is feasible. © 2012 IOP Publishing Ltd.
Original languageEnglish (US)
Pages (from-to)075012
JournalJournal of Micromechanics and Microengineering
Volume22
Issue number7
DOIs
StatePublished - Jun 7 2012

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

Fingerprint Dive into the research topics of 'Microencapsulation of silicon cavities using a pulsed excimer laser'. Together they form a unique fingerprint.

Cite this