Three- and Four-Point Bend Testing for Electronic Packages

Shetty, Santosh; Reinikainen, T.

doi:10.1115/1.1604158

Cited by 48 publications

(24 citation statements)

References 3 publications

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“…[58][59][60][61] The 3-point bending [3PB, shown in Fig. 4(a)] tests (initially developed to test thick samples for fracture strength [62][63][64][65] ) on 8 lm thick UTCs reveal a mechanical strength of $3 GPa. 66 Similar tests on UTCs embedded in flexible foil substrates 67 show an increase in fracture strength of up to $190% and a higher curvature of bending-which is up to $85% more than the UTCs which are not embedded in flexible substrates.…”

Section: Ultra-thin Chips and Mechanical Bendingmentioning

confidence: 99%

Bending induced electrical response variations in ultra-thin flexible chips and device modeling

Heidari

Wacker

Dahiya

2017

Applied Physics Reviews

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Electronics that conform to 3D surfaces are attracting wider attention from both academia and industry. The research in the field has, thus far, focused primarily on showcasing the efficacy of various materials and fabrication methods for electronic/sensing devices on flexible substrates. As the device response changes are bound to change with stresses induced by bending, the next step will be to develop the capacity to predict the response of flexible systems under various bending conditions. This paper comprehensively reviews the effects of bending on the response of devices on ultra-thin chips in terms of variations in electrical parameters such as mobility, threshold voltage, and device performance (static and dynamic). The discussion also includes variations in the device response due to crystal orientation, applied mechanics, band structure, and fabrication processes. Further, strategies for compensating or minimizing these bending-induced variations have been presented. Following the in-depth analysis, this paper proposes new mathematical relations to simulate and predict the device response under various bending conditions. These mathematical relations have also been used to develop new compact models that have been verified by comparing simulation results with the experimental values reported in the recent literature. These advances will enable next generation computer-aided-design tools to meet the future design needs in flexible electronics.

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Section: Ultra-thin Chips and Mechanical Bendingmentioning

confidence: 99%

Bending induced electrical response variations in ultra-thin flexible chips and device modeling

Heidari

Wacker

Dahiya

2017

Applied Physics Reviews

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“…A significant number of studies have been published that discuss the reliability of various electronic assemblies and packages subjected to four-point bend testing. [1][2][3][4][5][6][7][8][9][10][11] All these studies were carried out at cyclic frequencies between 1 Hz and 3 Hz and, as such, do not account for the timedependent (creep) behavior of solder interconnects. However, as seen in the literature, 12-14 a significant amount of creep can occur in solders even at room temperature.…”

Section: Introductionmentioning

confidence: 99%

Evaluating the Impact of Dwell Time on Solder Interconnect Durability Under Bending Loads

Menon

Osterman

Pecht

2015

Journal of Elec Materi

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With the increasing portability and miniaturization of modern-day electronics, the mechanical robustness of these systems has become more of a concern. Existing standards for conducting mechanical durability tests of electronic assemblies include bend, shock/drop, vibration, and torsion. Although these standards provide insights into both cyclic fatigue and overstress damage incurred in solder interconnects (widely regarded as the primary mode of failure in electronic assemblies), they fail to address the impact of timedependent (creep) behavior due to sustained mechanical loads on solder interconnect durability. It has been seen in previous studies that solder durability under thermal cycling loads is inversely proportional to the dwell time or hold time at either temperature extreme of the imposed temperature cycle. Fatigue life models, which include dwell time, have been developed for solder interconnects subject to temperature cycling. However, the fatigue life models that have been developed in the literature for solder interconnects under mechanical loads fail to address the influence of the duration of loading. In this study, solder interconnect test vehicles were subjected to cyclic mechanical bending with various dwell times in order to understand the impact of the duration of mechanical loads on solder interconnect durability. The solder interconnects examined in this study were formed with 2512 resistor packages using various solder compositions [tin-lead (Sn-Pb) and 96.5Sn-3Ag-0.5Cu (SAC305)]. To evaluate the impact of dwell time, the boards were tested with 0 s, 60 s, and 300 s of dwell time at both extremes of the loading profile. It was observed that an increase in the dwell time of the loading profile resulted in a decrease in the characteristic life of the solder interconnects. The decrease in fatigue life was attributed to increased creep damage as identified using finite-element simulations. An energy partitioning approach was then used to estimate the mean cycles to failure for the various testing conditions. The estimated mean cycles to failure were within 10% of the experimentally obtained mean cycles to failure.

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“…In addition, Rooney et al [2004] and Shetty and Reinikanine [2003] performed cyclic bending tests and Towashiraporn et al [2005] conducted a power cycling test. In this study, to increase the reliability of electronic package, various testing methods were developed and reliability evaluations were conducted.…”

Section: Introductionmentioning

confidence: 99%

Fatigue and fracture assessment for reliability in electronics packaging

2008

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Modern electronics products relentlessly become more complex, higher in density and speed, and thinner and lighter for greater portability. The package of these products is therefore critical. The reliability of the interconnection of electronics packaging has become a critical issue. In this study, the novel testing methods for electronic packaging are introduced and failure mechanisms of electronic packaging are explained. Electronics packaging is subjected to mechanical vibration and thermal cyclic loads which lead to fatigue crack initiation, propagation and the ultimate fracture of the packaging. A small-sized electromagnetic-type bending cycling tester, a micro-mechanical testing machine, and thermal fatigue testing apparatus were specially developed for the reliability assessment of electronics packaging. The long-term reliability of an electronic component under cyclic bending induced high-cycle fatigue was assessed. The high-cycle bending-fatigue test was performed using an electromagnetic-type testing machine. The time to failure was determined by measuring the changes in resistance. Using the micro-mechanical tester, low cycle fatigues were performed and compared with the results of a finite element analysis to investigate the optimal shape of solder bumps in electronic packaging. Fatigue tests on various lead-free solder materials are discussed. To assess the resistance against thermal loads, pseudo-power cycling method is developed. Thermal fatigue tests of lead-containing and lead-free solder joints of electronic packaging were performed using the pseudo-power cycling tester. The results from the thermal fatigue tests are compared with the mechanical fatigue data in terms of the inelastic energy dissipation per cycle. It was found that the mechanical load has a longer fatigue life than the thermal load at the same inelastic energy dissipation per cycle.

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Three- and Four-Point Bend Testing for Electronic Packages

Cited by 48 publications

References 3 publications

Bending induced electrical response variations in ultra-thin flexible chips and device modeling

Bending induced electrical response variations in ultra-thin flexible chips and device modeling

Evaluating the Impact of Dwell Time on Solder Interconnect Durability Under Bending Loads

Fatigue and fracture assessment for reliability in electronics packaging

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