用于制备高机械可靠性RF MEMS开关的新型工艺  

Novel process for fabrication of RF MEMS switch with high mechanical reliability

作　　者：胡光伟[1] 刘泽文[1] 侯智昊[1] 李志坚[1] 

机构地区：[1]清华大学微电子学研究所,北京100084

出　　处：《光学精密工程》2008年第7期1213-1217,共5页Optics and Precision Engineering

基　　金：国家自然科学基金资助项目(No.60576048);北京市科委基金资助项目(No.GYYKW05070014)

摘　　要：对介质桥串联接触式RF MEMS开关的制备工艺进行了研究。介绍了开关的结构,说明了采用常规制备工艺容易在桥膜上形成应力集中,严重影响开关的机械可靠性。通过改进工艺,提出了一种侧向钻蚀刻蚀介质桥膜下金属的方法,获得了平坦的介质桥膜。最后,给出了完整的开关制备流程。与常规工艺相比,新工艺避免了应力集中问题,提高了开关的机械可靠性,成品率从10%提高到了95%,工作寿命从1000次提高到了2.5×107次。此外,在23.3 V的驱动电压下,开关插入损耗<0.55 dB@DC-10 GHz,隔离度>53.2 dB@DC-10 GHz。结果表明该工艺可满足无线通讯对MEMS开关成品率、寿命和微波性能的要求。In order to improve the mechanical reliability and lifetime of a series contact Radio Frequency Microelectro-mechanical System（RF MEMS） switch with dielectric bridge, the fabrication process was studied. The switch structure was analyzed,the results illustrated that the mechanical reliability of the switch was debased with regular process because of the stress concentration of the bridge film. After that, an isotropic undercutting process for forming the upper control electrodes and contact bar under the bridge was proposed to obtain plane bridge film. Finally, the whole process of the switch was presented. Compared with the regular process, the proposed method can avoid the problem of stress concentration, and can improve the mechanical reliability of the switch. As a result, the yield rate of the switch increases from 10% up to 95%, the lifetime is improved from 1 000 cycles up to 2. 5×10^7 cycles. In addition, under the actuation voltage of 23.3 V, the insertion loss is less than 0.55 dB@DC-10 GHz, and the isolation is more than 53.2 dB@DC-10 GHz. These results show that proposed process can satisfy the modern wireless communication system requirements of yield rate, lifetime and microwave performance.

关 键 词：MEMS开关 接触式开关 机械可靠性 侧向钻蚀 寿命 

分 类 号：TN385[电子电信—物理电子学] TN62