Fabrication of Microcoils with Narrow and High Aspect Ratio Coil Line

摘要

Actuators are some of the most important elements in machines and robotics. The need for micro-fabrication of microactuators, smart sensors and microcoils is increasing. Actuators, which have a large volume and weight as part of a product, have been required to reduce their size. However, the processing required for three-dimensional micro-sized structures is very difficult. Here, the LIGA process could be used to fabricate nano- and micro-scale parts for many applications. Therefore, we have fabricated a spiral microcoil with narrow pitch and high aspect ratio coil line structures for an electromagnetic microactuator using the LIGA process. We have fabricated coil lines with a width of 10 μm and an aspect ratio of over 5 on an acrylic pipe surface using the X-ray lithography technique. Then, a void-free copper film was formed by electroforming in order to obtain coil lines. Finally, we have succeeded in obtaining a microcoil with an aspect ratio of over 2 using the isotropic etching process. We have also estimated the suction force of electromagnetic actuators using these microcoils. It is expected that these microcoils with a narrow and high aspect ratio structure could be capable of delivering high performance in spite of their miniature size.