Masaru Setomoto

Fabrication of Coil Lines with High Aspect Ratio for Electromagnetic Actuators

Actuators are finding increasing use in the various fields. And, it is one of most important parts for machines because it determines its performance. Actuators account for a large percentage and volume and weight of a product compared with other parts. Therefore, the progress in downsizing of actuators was required. Then, we have proposed a high aspect ratio coil lines for electromagnetic actuators in order to expect to reduce the size and increase the output power. To realize these coils and actuators, we have fabricated a three dimensional X-ray lithography and metallization process. Using these processes, we have formed three-dimensional coil lines with high aspect ratio that could be used in electromagnetic actuators. In this paper, we have fabricated coil lines with 10 mum line width, 20 mum pitch and aspect ratio of 5 on the surface of an acrylic pipe by mean of three-dimensional X-ray lithography technique. And, a void-free metallic deposit could be formed on a thin coil lines by electroplating method. It is very expected the high performance microcoils and actuators with high aspect ratio could be manufactured in spite of the miniature size.

Fabrication of high aspect ratio microcoils for electromagnetic actuators

The demand for micro-fabricated components and devices is continually increasing. Actuators can occupy a large volume and be a large part of the weight of an overall system, and therefore need to be reduced in size. However, there has been little progress in fabricating microactuators using existing technologies. Then, we have fabricated spiral microcoils with a narrow pitch and high aspect ratio structure for an electromagnetic type actuator using X-ray lithography and metallization techniques. We fabricated coils with 10 μm width coil lines with an aspect ratio of over 5. We also estimated the suction force of actuators using these microcoils. It is expected that these high aspect ratio microcoils would be capable of delivering high performance in spite of their miniature size.

Fabrication of Microcoils with Narrow and High Aspect Ratio Lines for Electromagnetic Actuators

Recently, actuators are finding the various fields and many applications. It is one of the most important components in various machines because its performance determines to operate a machine. The demand of micro- and nano- fabrications such as microactuators, microcoils, sensors, etc is increasing. To realize this demand, the key technology is processing of micro-fabrication. We are forcing on the electromagnetic actuators that could be driven at a low voltage and high efficiency. However, this type actuator is known to be unsuitable for miniaturization because current paths of coil lines are small in size. And, it is very difficult to make the microscopic coil lines with three dimensional structures. Therefore, we have fabricated and measured a solenoid type electromagnetic actuator with narrow pitch and high aspect ratio coil lines using X-ray lithography technique. Using this technique, we have obtained the coil lines with a width of 30 mum and an aspect ratio of about 3. It is very expected a high performance microcoil with high aspect ratio could be manufactured in spite of miniature size electromagnetic actuators.

Fabrication of High Aspect Ratio Microcoils Using X-Ray Lithography

Recently, the demand of micro-fabrications such as micro-sensors, microcoils, micro-actuators etc is increasing. Actuators account for a large percentage and volume and weight of a product compared with other parts. Therefore, the progress in downsizing of actuators was required. In order to resolve these problems, the key technology to realizing micro-devices is micro-fabrication process. Particularly, it is essential to the technologies for processing high aspect ratio structures in the production of micro-parts. We have proposed a three-dimensional fabrication process using X-ray lithography technique, and fabricated spiral microcoils having coil lines of narrow pitch and high aspect ratio structures. We have fabricated spiral microcoils at a pitch of 60 μm, and aspect ratio of about 5 using X-ray lithography and narrow metallization techniques on acrylic pipe surface. In addition, we also estimated the suction force of electromagnetic actuators using these microcoils. Measurement results were relatively in good agreement with theoretical values using high aspect ratio microcoils. It is very expected that the high performance microcoils could be manufactured in spite of miniature size.Copyright

Fabrication and estimation of electromagnetic type microactuators with microcoil

Recently, the requests for actuator are small size, high output power and lower electrical power, and so on. We are focusing on an electromagnetic type actuator. Nonetheless, this type actuator is known to be unsuitable for miniaturization because an allowable current carrying capacity is small. Therefore, we fabricated microcoil with narrow pitch and high aspect ratio using deep X-ray lithography and metallization techniques. If the aspect ratio is increased, cross section area of coil lines is also increased allowing a greater current path. We have fabricated coil lines with the width of 10 μm and the aspect ratio of over 5 on acrylic pipe surface. For current paths, copper layer was formed between narrow pitch thread structures on pipe by electroforming. Finally, isotropic copper etching was performed until the insulated portions of the wiring were exposed. We have estimated a suction force of electromagnetic actuator using this microcoil. The theoretical values by simulation and actual measurements of suction force were compared. These results are relatively in good agreement with theoretical values. Thus, it is very expected that microcoils with high aspect ratio and microactuators with high output force could be manufactured in spite of the miniature size.

Fabrication of high-aspect-ratio coil for electromagnetic actuators using LIGA process

Actuators are finding increasing use in the various fields. And, it is one of the most important parts of machine in motion because of determine its performance. Recently, the demands for various actuators are smaller size, higher output power, lower input electrical power, and so on. To realize these demands, the key technology is processing of microfabrication. We achieved development of the three-dimensional deep X-ray lithography technique for the spiral micro coil with a high inductance. Therefore, we have fabricated and estimated the solenoidal electromagnetic type microactuator of a low driving power by using this technique. This actuator having the high aspect ratio of coil line is also expected a great force in spite of miniature size. Now, we have obtained the coil line with the width of 10 μm and the aspect ratio of 5. We have also fabricated the measurement system for suction force of electromagnetic actuator. The coil model was measured by this system, and results were relatively in good agreement with simulation results. Using this high aspect coil made by X-ray lithography technique, the electromagnetic actuators have been expected to manufacture with high output force in smaller size.