Definition

Microsection (or cross-section) is a quality inspection technique where a PCB sample is cut, mounted in epoxy, polished, and examined under microscope. Microsectioning reveals internal features: copper thickness, plating quality, via fill, layer registration, laminate voids, and defects. It's a destructive test, performed on dedicated coupons or sample boards. Microsection analysis is required for IPC qualification, failure analysis, and first-article inspection. High-magnification SEM microsection can reveal nano-scale features and intermetallic compounds.