Fabrication of multi-layer eddy current micro sensors for non-destructive inspection of small diameter pipes

Introduction To improve the reliability of gas supplying installations, the non-destructive inspection of gas pipes is required. For this purpose, eddy current sensors are usually used. Since the fabrication of small-scale sensors had not been achieved, the inspection of gas pipes of small diameter (less than 20 mm) was not possible. We report in the present work on the fabrication of the small-scale sensors using photolithography and electroplating techniques. The fabrication process of micro sensors of 3 mm x 3 mm x 80 pm in dimensions and composed of 4 layers of micro planar micro spiral coils of 10 x 10 pm2 copper line has been performed.