This paper describes the newly developed processes of low temperature wafer bonding using plasma activation and deep dry silicon etching technologies. Both processes are a new type of “MEMS” (Micro Electro Mechanical System) process technology suitable for automotive pressure sensors. The conventional pressure sensor was a unified unit consisting of a silicon sensor chip and a glass stage. The diced unified unit was cut from a bonded disk of a processed silicon wafer and a glass stage substrate, and the silicon sensor chip incorporated four piezo-resistors, a diaphragm and bipolar-circuit. However, the pressure sensor had difficulty in accurately measuring pressure in the high temperature range because of the thermal strain caused by the thermal expansion coefficient difference between the silicon sensor chip and the glass stage. By changing the stage substrate material from glass to silicon, this has eliminated the difference of the thermal expansion coefficient between the silicon sensor chip and the stage, and resulted in making it possible to accurately measure pressure in a high temperature environment such as a vehicle's engine room. Furthermore, by introducing a newly developed low temperature wafer bonding process, this has led to the integration of the silicon sensor chip with a CMOS circuit. Additionally, by adopting a deep dry silicon etching process instead of the conventional wet etching process, which incidentally generated unnecessary bevel portions at the etched side walls of the diaphragm during etching, this has not generated the unnecessary bevel portions and resulted in reducing the diaphragm area and downsizing the silicon sensor chip.


    Access

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    New MEMS Process Technology for Pressure Sensors Integrated with CMOS Circuits


    Additional title:

    Sae Technical Papers


    Contributors:

    Conference:

    SAE 2014 World Congress & Exhibition ; 2014



    Publication date :

    2014-04-01




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    New MEMS Process Technology for Pressure Sensors Integrated with CMOS Circuits

    Asai, S. / Abe, R. / Isobe, Y. et al. | British Library Conference Proceedings | 2014


    A Modular CMOS Foundry Process for Integrated Piezoresistive Pressure Sensors

    Dahlmann, G. / Holzer, G. / Hering, S. et al. | British Library Conference Proceedings | 2005


    CMOS integrated elliptic diaphragm capacitive pressure sensor in SiGe MEMS

    Sundararajan, A. D. / Rezaul Hasan, S. M. | British Library Online Contents | 2014


    Smart CMOS pressure sensors

    Kandler,M. / Eichholz,J. / Manoli,Y. et al. | Automotive engineering | 1990


    Latchup in CMOS Integrated Circuits

    Soliman, K. A. / Nichols, D. K. | NTRS | 1985