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When assessing the mechanical durability of electronic assemblies, the focus is generally on the solder interconnect. However, in many package styles, such as BGAs (ball grid arrays), LGAs (land grid arrays), MLFs (micro lead frame) and QFNs (quad flat no-lead), the Cu trace emanating from the solder pad may be the weakest failure site, especially if the(More)
This study aims to establish a methodology for determining the residual contact stress developed during fabrication of non-conductive adhesive (NCA) bonded flip-chip-on-flex (FCOF) microelectronics systems. The method is demonstrated for a selected non-conductive adhesive. Fabrication of an NCA bonded FCOF system requires a compressive force large enough to(More)
In the conversion towards Pb-free electronics, there has been increasing interest in conductive adhesive interconnects, as they combine Pb-free materials with an attractive, low temperature, processing. One such promising packaging concept is direct bonding of flip-chip dies onto printed wiring boards (PWBs), with adhesive bonds between a gold-bumped(More)
This study focuses on quasi-static mechanical cycling durability of copper traces on printed wiring assemblies (PWAs). PWA specimens populated with Land Grid Array (LGA) components on copper-defined pads were cycled to failure under zero-to-max, three-point bending. Failure is defined in terms of electrical opens due to fatigue damage propagation through(More)
This study uses a global-local finite element study to determine the residual contact stress developed during fabrication of non-conductive adhesive (NCA) bonded flip-chip-on-flex (FCOF) systems. Electrical contact is made by pressure contact between gold bumps on the silicon die and gold coated copper bumps on the flex substrate. This study uses previous(More)
This dissertation investigates the fatigue durability of copper (Cu) traces on printed wiring assemblies (PWAs) under quasi-static cyclic mechanical flexure, using experimental results from a set of three-point bending fatigue tests, finite element (FE) modeling of the stresses generated during the cyclic bending tests, and response surfaces (RS) to(More)
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