High-Aspect-Ratio Micromachining of Fluoropolymers Using Focused Ion Beam
- PDF / 2,746,253 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 37 Downloads / 259 Views
1020-GG02-09
High-Aspect-Ratio Micromachining of Fluoropolymers Using Focused Ion Beam Yoshinori Matsui1, Nozomi Miyoshi2, Akihiro Oshima2, Shu Seki1, Masakazu Washio2, and Seiichi Tagawa1 1 The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan 2 Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo Shinjuku-ku, Tokyo, 169-8555, Japan
ABSTRACT Poly(tetrafluoroethylene) (PTFE) microstructure with high aspect ratio (> 200) and without solid debris along the edge was fabricated with high etch rate using FIB. Evolution of PTFE by FIB is responsible for the high aspect ratio, the high etch rate, and the no solid debris. Roughness of etched surface of the PTFE increases with fluence, although edge of the etched area has good profiles. The etch mechanism seems to be complicated. INTRODUCTION Fluoropolymers have excellent properties such as high thermal stability, high chemical stability, low adhesion, biological suitability, and low frictional resistance [1]. Micromachining of these polymers are very attractive for biomedical microelectromechanical system (BioMEMS) applications, e.g., flow cytometers, biological assays, and nano-filters. However, hand fabrication limits the ability of current devices to be effectively reduced in size. There was no suitable solvent for chemical etching of these polymers to perform wet bulk micromachining, thus micromachining of these polymers had been considerably difficult. Micromachining of these polymers have been intensively studied by pulsed laser ablation [2-4], or photo-etching with synchrotron radiation [5-7]. Micromachining with laser ablation is however not preferred, because resolution is poor and aspect-ratio, which is the ratio of the depth of microstructures to the pattern width, is quite low (∼2). Photo-etching by synchrotron radiation enable fluoropolymers to be etched with high-aspect-ratio [5-7]. This method uses contact mask with high cost, and the resolution partially depends on the mask with thickness enough to cut off the radiation. In order to realize applications in BioMEMS, micromachining of fluoropolymers with high resolution, high aspect ratio, high etching rate, excellent etch profiles is desirable. Focused ion beam micromachining (FIBM) is appropriate to achieve nanometer - micrometer modification because of the potential for allowing high resolution (approaching tens of nanometer). FIBM is carried out by scanning the ion beam over the desired area with material removal via radiation chemical reaction and physical spattering. Unfortunately, the physically sputtered materials redeposit along the edge of the etched area, and at last the sputtered materials cannot be removed from etching area. This process results in low etching rate, etch profiles with low aspect ratio, and reducing the resolution. Redepositon of removed material is therefore one of the most serious problem in FIB fabrication.
In the present study, we carried out micromachining of PTFE by FIB to produce mi
Data Loading...
