Application of eddy-current testing technique for high-density double-layer printed circuit board inspection

High-density double-layer printed circuit board (PCB) inspection based on the eddy-current testing (ECT) technique is proposed in this paper. The ECT probe, which consisted of a planar meander exciting coil and spin-valve giant magnetoresistance (SV-GMR) sensor array, is used for this propose. Defects on both the top- and bottom-layer of the high-density double-layer PCB are examined by the ECT technique with scanning over either the top or bottom layer. The characteristics of the proposed ECT probe for high-density double-layer PCB inspection are studied. The inspection results of the high-density double-layer PCB model verify that applying the ECT technique enables identification of the defects of both the top and bottom layer with one-side scanning.