Noise in conductive adhesive bonds under mechanical stress as a sensitive and fast diagnostic tool for reliability assessment

Vandamme, L.K.J.; Perichaud, Marie-Genevieve; Noguera, E.; Danto, Yves; Behner, U.

doi:10.1016/s0026-2714(99)00154-7

Cited by 1 publication

(1 citation statement)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The fabrication process with ACAs is shorter (and hence cheaper) than the process for solders, because there is no need for fluxing, cleaning, and underfilling. Because of these advantages ACAs are popular in several industries, including in Liquid Crystal Displays (LCDs), smart cards and labels, automotive applications, and portable microelectronics [4]. Finally, adhesive joints are more flexible than solder joints and may be able to withstand mechanical loading better.…”

Section: Introductionmentioning

confidence: 99%

Mechanics of Adhesively Bonded Flip-Chip-on-Flex Assemblies. Part I: Durability of Anisotropically Conductive Adhesive Interconnects

Haase

Farley

Iyer

et al. 2008

Journal of Adhesion Science and Technology

View full text Add to dashboard Cite

This is Part I of a two-part paper on adhesively bonded flip-chip-on-flex (FCOF) microelectronic assemblies. This paper examines the use of anisotropically conductive adhesives (ACAs), and the companion paper (Part II) addresses the use of non-conductive adhesives (NCAs). Two types of FCOF dies, bonded with ACAs, were subjected to temperature cycling and repeated temperature shock durability tests. The specimens have Au-plated bumps and the ACA contains Au-plated polymer particles. Specimens were fabricated with different bonding pressures. Scanning Electron Microscopy (SEM) investigations were performed to characterize the distribution and shape of the conducting particles.Contact resistance measurements, conducted throughout the temperature cycling durability test for 1000 temperature cycles between 20 • C and 115 • C, showed that resistance varied cyclically with each temperature cycle, but there was no increase in the average resistance over the duration of the test. In contrast, cyclic thermal shock tests between −50 • C and 115 • C produced failures within 200-2500 cycles, depending on the specimen configuration.Studies were conducted to examine the effect of specimen configuration and temperature on: (i) interconnect resistance, based on electro-thermal modeling; and (ii) mechanical contact stresses, based on thermomechanical modeling. Modeling techniques used detailed finite element analysis (FEA) as well as simpler rapid-assessment models based on 2D variational methods (for example, the Raleigh-Ritz method) and 1D electrical resistance networks. These models were used to parametrically investigate the influence of interconnect design, bonding pressure, temperature and interconnect degradation mechanisms, on the contact resistance and contact stresses.Results suggested that the thermal expansion of the ACA during temperature cycling did not cause any changes in the contact resistance at the contact interface, thus suggesting the possibility of bonding at AuAu interfaces. During thermal shock, the expansion mismatch stress between the die and Printed Wiring Board (PWB) at the low temperature (−50 • C) was probably sufficient to fracture this bond. The issue of gold-to-gold bonding will be addressed in a future paper.

show abstract

Section: Introductionmentioning

confidence: 99%