Using 3D tomography affords otherwise infeasible perspectives, such as virtual cross‐sections in the lateral plane of the attachment. This same sample‐study is about observing how the fine‐scale structure of a sintered attachment evolves and degrades over time. However, their degradation mechanisms are not as well understood. Sintered nanosilver die‐attachments have been proposed as a more reliable and environmentally friendly alternative to solder alloy joints for emerging power electronics module designs. This paper concerns the use of three‐dimensional (3D) X‐ray tomography, a nondestructive technique, to perform cradle‐to‐grave studies of sintered nanosilver die‐attachments under operation. Finally, cracks within the sintered joint are shown to have a negligible impact on the conduction pathway of the joint due to their aspect ratio and orientation with respect to the assembly. Examination of the texture (differing levels of X‐ray absorption) of virtual cross‐sectional images reveals the origins of the nonuniformity of densification. Evidence is provided of heterogeneous densification within the sintered joint under power cycling, and this is shown to play a major role in driving the initiation and propagation of the cracks. The propagation characteristics of these cracks within the substrate are analysed.
DATACON 2200 EVO PLUS REVIEWS CRACK
Crack fronts which develop in the most porous regions within the sintered attachment layer travel across the boundary into the copper substrate. Lateral views of crack development are presented, which show networks analogous to mud‐cracks.
This enables contextualization of some of the fine‐scale properties which underpin the large‐scale damage observed via tomography. Morphologies were extracted from tomography data and integrated with data from microscopy modalities at different resolution levels. A time‐lapse study of thermomechanical fatigue damage has been undertaken using three‐dimensional X‐ray computer tomography.