Study On MEMS Capacitive Pressure Sensor Based On Porous Silicon Sacrificial Layer

As an important sensor used widely in modern production and living,pressure sensor has a 70-year history. With the development of microelectronic industry, pressure sensor has been developed in the direction of intellectualization, miniaturization and intelligence.Based on the new method and equipment of preparation of porous silicon, this dissertation proposes a novel structure of MEMS capacitive pressure sensor based on porous silicon sacrificial layer. This dissertation also shows the production process of the novel sensor. The thesis specific main wok and results are as follows:(1) Based on double-tank electrochemical etching method, the novel method and equipment of porous silicon preparation is studied. A novel equipment of double-tank electrochemical etching method is designed. The novel equipment can satisfy the needs of porous silicon preparation on normal silicon wafer and SOI wafer and it can prepare porous silicon with different shapes and numbers. The novel equipment has advantages in simple construction, easy operation and high security.(2) Based on the basic structure of capacitive pressure sensor,a novel structure of MEMS capacitive pressure sensor based on porous silicon sacrificial layer is proposed.The square P++ type silicon membrane with slots is used as sensitive layer. The flat membrane and slotted membrane are have been analyzed and compared with ANSYS.(3) The process for processing MEMS capacitive pressure sensor based on porous silicon sacrificial layer is proposed.