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Wafer Test Workshop

Jory Twitchel, Jerry Broz and Gunther Boehm

A real life pad crack study

Gunther Boehm's and Jory Twitchell's presentation focused on the analysis of the occurrence of undesirable pad cracks, i.e. the risk of damage to deeper wafer structures during probing.

Bond pads on microchips are exposed to the risk during the probing process that the scrub mark of the needle will cause cracks in the sub-pad structure. This can lead to long-term reliability risks. In various experiments, some of the most important factors influencing the development of such pad cracks were investigated. Wafers were contacted, scrub marks measured and the metal coating of the bond pad removed to make cracks visible that may have formed underneath.

As particularly important parameters have been identified: the shape of the needle tip, the way of probing movement and the quality of the tip cleaning. It could be demonstrated that a careful determination of these parameters allows a crack-free test operation.

All presentations of the workshop can be found directly on the corresponding page of the event (link below), the award-winning presentations can be found at "Awarded Presentations".