Development of a 3-Dimensional LIGA Process and Application to Fabricate a Spiral Microcoil

LIGA process has been developed in the 2.5-dimensional world. We introduced new technologies of a 3D X-ray lithography and a worm injection molding with an unscrewing de-molding mechanism, and succeeded in the deployment of a 3D LIGA process. Furthermore, we fabricated a spiral microcoil using the 3D-LIGA process and a metallization technique combining flat and smooth electroplating and isotropic chemical etching. The microcoil diameter was 0.5 mm and the length was 1 mm. The width of coil lines was 10µm and the pitch was 20µm. Characteristics of this microcoil as an inductor combine the inductance of 91 nH and the quality factor of 5.8 at the frequency of 1 GHz. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(1): 43–51, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20679