A new experimental approach to investigate the physics-of-failure of wirebond interconnects

Master thesis (2018)

Authors

H. KOPALLY Electrical Engineering, Mathematics and Computer Science

Contributors

W.D. van Driel (supervisor 1)
H.W. van Zeijl (supervisor 2)
A. Bossche (supervisor 2)
P.J. French (supervisor 2)
Faculty
Electrical Engineering, Mathematics and Computer Science
Copyright: © 2018 Hima Kopally
Fatigue Interconnects Wire bonding Physics-of-failure Four wire resistance measurement
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Published Date

21-08-2018

Language

English

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Faculty

Electrical Engineering, Mathematics and Computer Science

Abstract

Wirebonding is an interconnection technology used to connect a chip to its LED package. It is currently not well understood which wirebond characteristics are best to tailor to prevent the failure of wirebonds. The focus of this thesis is to understand the physics-of-failure of wirebonds via an experimental approach. Therefore, an experimental setup is designed which can accurately measure the resistance of the wirebond samples by four-wire resistance measurements. Furthermore, Finite Element simulations are done to understand the physical nature of wirebond failure better.

Gold wirebonds with different loop geometries have been designed and made which are then subjected to temperature cycling. It is found through 4-wire experimental resistance setup that when a significant increase in resistance is reported, wirebond fatigue is imminent. Coffin-Manson based Finite Element
simulations show that stresses at the neck are higher than at the heel. In retrospect, when the wirebond samples are encapsulated in Silicone, there is an increase in the stresses at the heel.