Corrosion in plastic packages-sensitive initial delamination recognition

The interface between the molding compound (MC) and the chip surface is of considerable interest for failure analysis on plastic-packaged chips. Scanning acoustic microscopy (SAM) is widely used for nondestructive evaluation in this field. Prior research of stressed components has shown that some delaminations containing microbridges, or "spongy" elements, are undetectable by SAM. Corrosion proves to be a sensitive mechanism for detecting these failures. In certain cases corrosion can be detected quasinondestructively by IR microscopy, while conventional destructive physical analysis and optical microscopy remain the easiest way to assess it. Degradation of the interface molding compound and chip is detectable by SAM at a later stage.<
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