Full Content is available to subscribers

Subscribe/Learn More  >

Laser Bonding and Modeling for Wafer-Level and Chip-Scale Packaging of Micro-Electro-Mechanical Systems

[+] Author Affiliations
Yi Tao, Ajay P. Malshe, W. D. Brown

University of Arkansas, Fayetteville, AR

Paper No. IMECE2002-39271, pp. 55-60; 6 pages
  • ASME 2002 International Mechanical Engineering Congress and Exposition
  • Electronic and Photonic Packaging, Electrical Systems Design and Photonics, and Nanotechnology
  • New Orleans, Louisiana, USA, November 17–22, 2002
  • Conference Sponsors: Electronic and Photonic Packaging Division
  • ISBN: 0-7918-3648-7 | eISBN: 0-7918-1691-5, 0-7918-1692-3, 0-7918-1693-1
  • Copyright © 2002 by ASME


In this work, low temperature selective solder (Pb37/Sn63) bonding of silicon chips or wafers for MEMS applications using a continuous wave (CW) carbon dioxide (CO2 ) laser at a wavelength of 10.6μm was examined. The low reflectivity, fair transmittance, and high absorptivity of silicon at the 10.6μm wavelength led to selective heating of the silicon and reflow of an electroplated or screen printed intermediate solder layer which produced silicon-solder-silicon joints. Finite element simulations were carried out to optimize the process parameters in order to achieve uniform heating and minimum induced thermal stress. The bonding process was performed on the fixtures in a vacuum chamber at an air pressure of one milliTorr to achieve fluxless soldering and vacuum encapsulation of silicon dies. The bonding temperature at the sealing ring was close to the reflow temperature of the eutectic lead tin solder, 183°C. Pull test results showed that the joint was sufficiently strong and could not be separated before the silicon die broke. Helium leak testing showed that the leak rate of the package was below 10−8 atm · cc/sec under optimized bonding conditions. The results of the Design of Experiment (DOE) method indicated that both laser incident power and scribe velocity significantly influenced bonding results. This novel method is especially suitable for vacuum bonding wafers containing MEMS and other micro devices with low temperature budgets where managing stress distribution is important. Further, sealed encapsulated and released wafers can be diced without damaging the MEMS devices at wafer scale.

Copyright © 2002 by ASME



Interactive Graphics


Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In