應用於射頻電路上低溫製程之SU-8射頻微機電串聯型開關

Abstract

此篇文章在於介紹新穎的製程在於矽基材上，利用SU-8材料及微加工過程去製作射頻微機電開關。開關是被設計成雙側固定端，且利用靜電力驅動的SU-8 (1.7μm) /銅(0.6μm) /SU-8 (2.6μm)三層結構的懸壁梁開關。此為結構開關的特性，包括在12GHz內，擁有小於0.76dB介入損失和 大於 27.8dB各離性。雖然此被製作出來的微機電開關的驅動電壓為46伏特，但此結構的微機電開關可以在被設計較低驅動電壓的開關，例如設計較薄的懸壁樑結構、更大的驅動電壓面積已及較長型的懸壁樑。然而，由於此SU-8製程全成過程的製程溫度低於135°C， 我們相信擁有低溫特性的SU-8製程將會有效地實現射頻微機電開關整合於系統晶片上的可能。

The paper presents a novel SU-8 micro-maching process for series RF MEMS switch fabrication on a silicon substrate. The switch is designed with a clamped-clamped SU-8 (1.7μm) /Cu (0.6μm) /SU-8 (2.6μm) bridge structure driven by electrostatic force. The performances of the switch include □ 0.76dB insertion loss and □ 27.8dB isolation up to 12GHz. Although the actuation voltages is about 46V, the structure can be further designed with less beam thickness, larger actuated electrode and longer beam length for low voltage actuation. Since the whole fabrication process can be kept below 135°C, it is our belief that the low temperature characteristic of the SU-8 process will realize cost-effective RFMEMS switches for integrated CMOS RF SOC (System-on-a-Chip) application.