DEVELOPMENT OF SURVIVABILITY ENVELOPES FOR SnAg LEADFREE PACKAGING ARCHITECTURES UNDER SHOCK AND VIBRATION

摘要

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.