Department of Mechanical Engineering
Chungbuk National University
Cheongju Chungbuk, Korea
Seungming Cho and Bongtae Han
CALCE Electronic Products and Systems Center
University of Maryland
College Park, MD 20742
A robust scheme of moire interferometry for real-time observation is employed to study the temperature dependent thermo-mechanical behavior of a ceramic ball grid array package assembly. The scheme is implemented with a convection-type environmental chamber that provides the rapid temperature control required in accelerated thermal cycling. Thermal deformations are documented at various temperatures. Thermal-history dependent analyses of global and local deformations are presented. A significant non-linear global behavior is documented due to complete stress relaxation at the maximum temperature. An analysis of solder interconnections reveals that inelastic deformation accumulates at the bottom eutectic solder fillet only at high temperatures.
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