Development of survivability envelopes for SnAg leadfree packaging architecures under shock and vibration

In this paper, the accuracy of optical measurements based on digital image correlation (DIC) with ultra high-speed imaging has been investigated for full-field measurement of transient strain in various board assemblies subjected to shock in various orientations. Previous researchers have measured the transient-dynamics of board assemblies with high-speed imaging in conjunction with high-speed image analysis for measurement of relative displacement, angle, velocity, and acceleration [1, 2], high-speed data-acquisition systems with discrete strain gages [3, 4, 5] and with accelerometers for measurement of transient acceleration [6, 7, 8]. Survivability envelope approach for leadfree area array architectures based on high-speed optical measurements and statistical pattern recognition has been presented. Degradation in confidence value gives a leading indication of component failure. Package architectures examined include-flex ball-grid arrays, tape-array ball-grid arrays, and metal lead-frame packages. Explicit finite-element models have been developed and correlated with experimental data. Models developed include, smeared property models, Timoshenko-beam models, and explicit sub-models.