Laser joining of glass to silicon using adhesive for MEMS packaging applications

F. Bardin, S. Kloss, C. H. Wang, A. Moore, A. Jourdain, I. De Wolf, D. P. Hand

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

2 Citations (Scopus)

Abstract

Laser joining is a promising technique for wafer-level bonding. It avoids subjecting the complete MEMS package to a high temperature and/or the high electric field associated with conventional wafer-level bonding processes, using the laser to provide only localized heating. We demonstrate that a benzo-cyclo-butene (BCB) polymer, used as an intermediate bonding layer in packaging of MEMS devices, can be satisfactorily cured with a substantial reduction of curing time compared with an oven-based process by using laser heating. A glass-on-silicon cavity bonded with a BCB ring can be produced in few seconds at typical laser intensity of 1 W/mm2 resulting in a local temperature of ~ 300°C. Hermeticity and bond strength tests show that such cavities have similar or better performance than cavities sealed by a commercial substrate bonders which require a minimum curing time of 10 minutes. The influence of exposure time, laser power and pressure on degree of cure, bond strength and hermeticity is investigated. The concept of using a large area, uniform laser beam together with a simple mirror mask is tested, demonstrating that such a mask is capable of protecting the centre of the cavity from the laser beam; however to prevent lateral heating via conduction through the silicon a high conductivity heat sink is required to be in good thermal contact with the rear of the silicon.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
Volume6107
DOIs
Publication statusPublished - 2006
EventFiber Lasers III: Technology, Systems, and Applications - San Jose, CA, United States
Duration: 23 Jan 200626 Jan 2006

Conference

ConferenceFiber Lasers III: Technology, Systems, and Applications
Country/TerritoryUnited States
CitySan Jose, CA
Period23/01/0626/01/06

Keywords

  • Laser bonding
  • MEMS packaging
  • Wafer bonding

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