Fabrication of micromachined hotplates by combining the PolyMUMPs technology with self-aligned post-processing steps

Abstract

In this article, we propose a process to fabricate micromachined hotplates, by leveraging the multiuser MEMS process known as PolyMUMPs from MEMSCAP. The PolyMUMPs technology is complemented through self-aligned post-processing steps. This procedure eliminates the requirement of aligning masks during post-processing and enables easy prototyping of microhotplates. Two designs were fabricated, including microhotplates with gold interdigitated-electrodes and temperature sensors. The final device features a suspended membrane with dimensions of 400 × 120 μm2 and can achieve a heating temperature of 300 °C while consuming 24.1 mW of power. Long-term heating tests showed that the device can withstand a continuous heating process for more than 150 h at a temperature of 400 °C. These properties make the device suitable for targeting a wide range of applications, including the heating platform of metal-oxide type gas sensors.