Process for Patterning Indium for Bump Bonding

TBMG-15263

12/01/2012

Abstract
Content

An innovation was created for the Cosmology Large Angular Scale Surveyor for integration of low-temperature detector chips with a silicon backshort and a silicon photonic choke through flip-chip bonding. Indium bumps are typically patterned using liftoff processes, which require thick resist. In some applications, it is necessary to locate the bumps close to high-aspect-ratio structures such as wafer through-holes. In those cases, liftoff processes are challenging, and require complicated and time-consuming spray coating technology if the high-aspect-ratio structures are delineated prior to the indium bump process. Alternatively, processing the indium bumps first is limited by compatibility of the indium with subsequent processing. The present invention allows for locating bumps arbitrarily close to multiple-level high-aspect-ratio structures, and for indium bumps to be formed without liftoff resist.

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Citation
"Process for Patterning Indium for Bump Bonding," Mobility Engineering, December 1, 2012.
Additional Details
Publisher
Published
Dec 1, 2012
Product Code
TBMG-15263
Content Type
Magazine Article
Language
English