Acoustic Screening to Remove SUSPECT PLASTIC Components

摘要

In an ideal world, plastic-encapsulated microcircuits (PEMs) would leave the component manufacturer in pristine condition. BGAs, QFNs, PQFPs, TOs and other package types would have no electrical or structural anomalies that could lead to electrical failures. The components would arrive for assembly in this condition, and would pass through handling, reflow and testing with no alteration of their ideal state. They would give years of flawless service.In the real world, things do not always work out like this. A component may pick up a gap-type structural anomaly - delaminations, voids and cracks are the common ones - somewhere between the molding process and post-assembly shipment.