Study on direct etching of poly(tetrafluoroethylene) by high-energy heavy ion beams

• PTFE can be etched directly using MeV region high energy heavy ion beam.
• The etching rates tended to increase with the atomic number (Z) of ion species.
• There are thresholds of irradiation dose for the etching, depending of Z of ions.
• The etching is mainly proceeded by both chain scission and decomposition from medium.
• Micro-fabrication of PTFE using Ni mesh mask was succeeded with fine pattern.

Micro-fabrication of poly(tetrafluoroethylene) (PTFE) was carried out using a high-energy heavy ion beam in the MeV region. PTFE was irradiated with various ions (6 MeV/u) under vacuum (<1.0×10−4 Pa) at room temperature (298 K). The surface of the irradiated PTFE was observed by laser microscopy and a scanning electron microscope (SEM). Micro-scale fabrications of PTFE were successfully performed by direct ion beam etching. Under our experimental conditions the etching proceeded more effectively by heavy ion beams (larger than N7+), compared with lower-energy ion beams (keV region). A larger atomic number (Z) of the irradiating ion induced higher etching rates in PTFE; the etching rate for Ne10+ and Xe54+ changed from 6.5×10−13 to 2.0×10−11 μm/(ion cm−2), respectively. As a result we suggest that due to their high electronic stopping powers, etching could be efficiently achieved using high-energy ion beams.