一种用于高机械可靠性RF MEMS开关制备的新型工艺

为提高介质桥串联接触式MEMS开关的工作寿命，本文改进了常规制备工艺，提出一种侧向钻蚀刻蚀介质桥膜下金属的方法，以获得平坦的介质桥膜，制备得到高机械可靠性的开关。与常规工艺相比，新工艺避免了应力集中问题，成品率从10％提高到了95％，工作寿命从1000次提高到了2500万次。在23.3V的驱动电压下，开关插入损耗 0.55dB＠DC-10GHz，隔离度 53.2dB＠DC-10GHz。

A novel process for fabrication of high mechanical reliability RF MEMS switch

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 2.5×107 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.