Low Cost and High Resolution X-Ray Lithography for Fabrication of Microactuator

Abstract

In this work, low-cost and high resolution X-ray lithography is developed by employing low-cost sputtered lift-off lead film on mylar sheet substrate and applied for fabrication of electrostatic actuators. X-ray mask was fabricated by conventional photolithography, Pb sputtering and lift-off process. The Pb mask is used for X-ray lithography of electrostatic actuator structures with 5 µm interdigitate electrodes. For 140 µm-thick SU-8 photoresist on Cr-coated glass substrates, Pb film thickness of around 10 µm was used to block X-ray with 95% x-ray image contrast at a critical dose of 4,200mJ/cm3. A high aspect ratio of 26.5 of SU8 microstructure with 5 µm lateral resolution has been achieved by the developed low cost Pb based X-ray mask. In addition, a steep sidewall angle of nearly 90o for SU-8 structure is confirmed. The results demonstrate that the Pb based X-ray mask offers high resolution X-ray lithography at a very low cost and is promising for microactuator applications.