Meaning
Metallographic cross-section inspection procedures evaluate the internal structural integrity and plating thickness of printed circuit board microvias and barrel walls. Performing microsectioning verification enables quality engineers to detect internal physical defects such as plating voids, barrel cracks and delamination hidden within multilayer circuit assemblies. Electronics quality assurance laboratories employ this destructive testing method to validate circuit board manufacturing processes against military and IPC standards.
The inspection scope covers drilled holes, plated copper layers and dielectric interfaces, concluding once optical microscopy analysis and dimensional measurements are recorded.
Preparation Protocol
Specimen preparation protocols require potting circuit board coupons in synthetic resin before grinding and polishing sample surfaces. Conducting microsectioning verification involves microscopic examination of highly polished cross-sections under optical or scanning electron microscopes. Technicians apply chemical etchants to reveal copper grain structures and plating layer boundaries.
Defect Detection
Internal physical anomalies visible under magnification reveal underlying defects in drilling, desmear or electroplating steps. Integrating microsectioning verification into lot release protocols prevents defective board batches from entering automated component placement lines. Inspection reports quantify copper plating thickness across via walls to verify compliance with minimum thickness specifications.
Acceptance Threshold
Printed circuit board lots fail quality verification when microsection photos reveal plated hole copper thickness below specified IPC standards.
