Interface structure and strength of ultrasonically wedge bonded heavy aluminium wires in Si-based power modules

Dynamic Modeling Method of Electro-Thermo-Mechanical Degradation in IGBT Modules

“…As would be expected, the degree of wear is seen to increase gradually with state in lifetime, however, no chip hotspot effects are observed around the center wires. The latter [14]). is in contrast to previous presented results [6], [7] where the chip center tend to trap heat due to geometry.…”

“…Detailed information on online monitoring methodologies, power cycling setup, and visual inspection results are available in [5], [17], and [19]. Following power cycling the modules were experimentally investigated by four-point probing [20], [21] of electrical parameters and microinvestigation using SEM/FIB and microsectioning [14]. No significant degradation was observed in the chip or baseplate solder in any of the samples, accordingly, further investigation was centred on chip topside interconnects.…”

“…It has been reported that changes of, e.g., wire curvature alone as well as bond footprint affect the lifetime directly [13], [14]. Accordingly, accurate fitting of empirical models is paramount.…”

Damage Evolution in Al Wire Bonds Subjected to a Junction Temperature Fluctuation of 30 K

“…The X-Y plane images show shell-nut shaped footprints typical for wire bonds and often observed after shear testing or lift-off events. 26,30 A pre-cracked area is visible at the bond tail end on the right hand side of both bonds (these are highlighted and annotated A in Fig. 4).…”

“…The lack of clarity is attributable to several factors, including the ambiguous nature of the wire bonding mechanism itself, over which there are still a number of views. [20][21][22][23][24][25][26] This is compounded by the fact that the concept of fatigue damage generally lags behind other wear out phenomena in terms of the degree of understanding and consensus of relevant mechanisms of initiation, accumulation, and how these may be quantified. [27][28][29] In view of all these factors, the additional insight that can be gained from a 'same sample' x-ray computed tomography study is instrumental.…”