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The reliability of integrated circuit (IC) packages depends in many respects on their mechanical integrity. The effect of structural weaknesses caused by poor bonding, voids, microcracks or delaminations may not be evident in the electrical performance characteristics, but may cause premature failure. C-mode scanning acoustic microscopy (C-SAM) is an excellent tool for non-destructive failure analysis of IC packages. It has exhibited good sensitivity to interface anomalies such as poor bonding, delamination, voids, cracks, and foreign material inclusions. The non-destructive ultrasonic test method using C-SAM is a common detection method for delamination or crack failures in semiconductors with reliable and relatively accurate results. This paper will demonstrate the effectiveness of C-SAM at non-destructively analysis from A-Scan, B-Scan, C-Scan and T-Scan respectively. And the capability of C-SAM in detecting IC surface corrosion will be also illustrated.

Via delamination, a novel electromigration failure mechanism, has been investigated and understood. The mass transport model, in conjunction with environmental, thermal, and mechanical stresses was proposed to explain this failure mechanism. Process enhancements, which include lowering the thin film stresses and strengthening the adhesion between the tungsten plug/metal stack and metalhnter-level dielectric interfaces, have effectively eliminated this reliability failure mode.