PCB conductor dimension and alignment inspection by using ECT probe with SV-GMR sensor

Inspection of bare printed circuit boards (PCBs) consists of evaluating not only imperfections in the PCB conductor but also PCB conductor dimensions and alignment. An eddy-current testing (ECT) probe consisting of a spin-valve giant magneto-resistance (SV-GMR) device was used as a magnetic sensor, with a planar meander coil as an exciter, and applied to PCB conductor dimension and alignment inspection. High-frequency