Evaluation of the Mechanical Integrity of Beam Lead Devices and Bonds using Thermomechanical Stress Waves

A novel technique for either destructive or non-destructive evaluation of the mechanical integrity of beam lead transistors and integrated circuits has been demonstrated. A Febetron 705 flash electron beam machine was used to generate thermomechanical stress waves which were acoustically coupled to bonded beam lead devices. Computer aided stress wave analysis of the system was used to calculate the stresses generated in the individual beams. This allows prediction of failure modes and levels. Experimental results have demonstrated that failure modes can be related to device or bonding deficiencies, and reveal failures which cannot be easily obtained by other methods of testing.