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Die crack, which is the fracture of the silicon die substrate, results in the loss of device functionality. Newer thin plastic packages have approximately half the thickness of silicon die and plastic encapsulant as regular packages,
and are more vulnerable to die cracking. This paper presents the various die cracking mechanisms that can be observed in thin packages. Five example cases of die cracking were presented according to their causes: 1) die cracks due to the presence of die backside damage or edge chip-out resulting from an old backgrind process; 2) die cracks due to die edge chip-outs caused by improper wafer sawing; 3) die cracks induced by uneven die attach ejection due to planarity problems with the die ejector needles; 4) die cracks due to die backside damage caused by improperly set ejector needles; and 5) die cracks due to stresses imparted by lead conditioning equipment. This paper presents a best-known method (BKM) for the analysis of die cracking, in the light of optimization of new FA techniques. Fractography was likewise confirmed to be an important technique for determining the origin of
a die crack. |
