A Highly Manufacturable Large Area Array MEMS Probe Card Using Electroplating and Flipchip Bonding
Bong-Hwan Kim; Jong-Bok Kim; Jong-Hyun Kim
Industrial Electronics, IEEE Transactions on
Volume 56, Issue 4, April 2009 Page(s):1079 - 1085
Digital Object Identifier 10.1109/TIE.2008.2003366
Summary:A highly manufacturable microelectromechanical systems (MEMS) probe card was developed by using flipchip bonding technology, which is applicable to large area array bonding ranging from 2- to 8-in substrates. A cantilever-type probe structure for an actual device was electroplated with nickel-cobalt and was bonded with nickel bump, which anchored on the ceramic substrate. Gold-tin (AuSn) was used as the material of flipchip bonding between the cantilever beam and bump. Flipchip bonding itself is not a new technology, but combining it with a MEMS probe card is a novel technique in large area bonding because of the high reflow temperature (280degC, Au80Sn20). Various parallelism bonding processes were used to find the best bonding method. The MEMS probe card was designed to achieve a deflection of 50 mum when 2 gram force (gf) was applied and to keep elasticity up to a deflection of 150 mum. The specification of the probe card was for actual 12-in dynamic random access memory testing. The measured average contact force was 2.04 gf at a 50-mum overdrive. In addition, mechanical and electrical characteristics were also suitable for the actual device test.
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