MEMS矢量水听器敏感结构的后CMOS释放工艺研究

Research on post-CMOS release process of sensitive structure of MEMS vector hydrophone

纤毛式微机电系统(MEMS)矢量水听器可探测水下质点振速等矢量信息,与互补金属氧化物半导体(CMOS)集成能够很大程度地提升其性能。针对纤毛式MEMS矢量水听器的CMOS集成提出了一种方案,该方案在MEMS后处理工艺中,利用侧墙保护和各向异性湿法腐蚀从正面释放水听器的十字梁敏感结构。整个后处理过程不需要光刻,降低加工难度的同时,保证了加工结构的精确性。设计出了一种验证性的工艺流程,具体分析了4种不同结构的湿法腐蚀过程。最终完成了这4种结构的工艺流片,对实验结果进行了分析。实验验证了该方案的可行性,为纤毛式MEMS矢量水听器的CMOS集成奠定了基础。

Cilium MEMS vector hydrophone can detect vector information such as the underwater particle vibration velocity.Integrating with complementary metal oxide semiconductor(CMOS),can greatly improve its performance.A scheme for integration of cilium MEMS vector hydrophone with CMOS is proposed.In the MEMS post-treatment process,the cross beam sensitive structure of the hydrophone is front-side released by sidewall protecting and anisotropic wet etching.The whole post-treatment process does not need lithography,reducing the difficulty of processing while ensuring the precision of processing structure.A verification process is designed,and wet etching processes of four different structures are analyzed concretely.Finally,tape-out of processes of the four structures are achieved and the experimental results are analyzed.The experiment verifies the feasibility of the scheme,which lays a foundation for CMOS integration of cilium MEMS vector hydrophone.