Examination Regime
Post-assembly metallurgical sectioning, decapsulation and chemical deprocessing verify internal component construction and solder joint integrity through irreversible specimen disassembly. Destructive physical analysis evaluates raw materials, hermetic seals, internal wire bonds and diffusion barriers against procurement specifications. High-reliability space, defense and medical procurements mandate these destructive audits on statistical sample units drawn from production lots before flight release.
Sectioning Workflow
Specimen preparation begins with acoustic microscopy or radiographic baseline imaging to locate internal structural voids. Precision diamond sawing isolates critical package features without inducing secondary mechanical fractures. Epoxy encapsulation secures the specimen inside an epoxy puck, which undergoes progressive mechanical grinding using silicon carbide papers followed by diamond polishing suspensions down to sub-micron particle sizes.
Chemical etching exposes intermetallic layers, grain boundary networks and gold-aluminum intermetallic compounds under scanning electron microscopy. Sample lots fail destructive physical analysis when technicians identify voiding, anomalous intermetallic growth, pad lifting or unbonded die interfaces that breach MIL-STD-1580 acceptance criteria.
Risk Containment
Lot rejection prevents contaminated or structurally defective active components from entering high-reliability PCBA production queues. Counterfeit die identification and unauthorized internal material substitutions become visible during chemical decapsulation and die mark inspection. High procurement costs for sacrificial samples are balanced by the mitigation of catastrophic field failures in unserviceable operating environments.
