Fabrication of electromagnetically-driven tilted microcoil on polyimide capillary surface for potential single-fiber endoscope scanner application

The design and fabrication of a Micro-electromechanical Systems (MEMS)-based tilted microcoil on a polyimide capillary are reported in this paper, proposed for an electromagnetically-driven single-fiber endoscope scanner application. The parameters of the tilted microcoil were optimized by simulation. It is proved that the largest driving force could be achieved when the tilt-angle, the pitch and the coil turns of the designed microcoil were 60°, 80 μm and 20, respectively. The modal simulation of the designed fiber scanner was carried out. The prototypes of the tilted microcoils were fabricated on the surface of polyimide capillary with 1 mm-diameter using our developed cylindrical projection lithography system. The dimensions of the two tilted microcoils were as follows: one was tilt-angle 45°, line width 10 ± 0.2 μm, coil pitch 78.5 ± 0.5 μm, and the other was tilt-angle 60°, line width 10 ± 0.2 μm, coil pitch 81.5 ± 0.5 μm. Finally, a direct mask-less electroplating process was employed to fabricate the copper microcoil with 15 μm thickness on the gold (Au) seed-layer, and the corresponding line width was expanded to 40 μm.