JSTS:Journal of Semiconductor Technology and Science

The Institute of Electronics and Information Engineers (대한전자공학회)
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The Active Dissolved Wafer Process (ADWP) for Integrating single Crystal Si MEMS with CMOS Circuits

  • Karl J. Ma (Center for Integrated Sensors and Circuits University) ;
  • Yogesh B. Glanchandani (Univ. of Michigan) ;
  • Khalil Najafi (Center for Integrated Sensors and Circuits University)
  • Published : 2002.12.01
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Abstract

This paper presents a fabrication technology for the integration of single crystal Si microstructures with on-chip circuitry. It is a dissolved wafer technique that combines an electro-chemical etch-stop for the protection of circuitry with an impurity-based etch-stop for the microstructures, both of which are defined in an n-epi layer on a p-type Si wafer. A CMOS op. amp. has been integrated with $p^{++}$ Si accelerometers using this process. It has a gain of 68 dB and an output swing within 0.2 V of its power supplies, unaffected by the wafer dissolution. The accelerometers have $3{\;}\mu\textrm{m}$ thick suspension beams and $15{\;}\mu\textrm{m}$ thick proof masses. The structural and electrical integrity of the fabricated devices demonstrates the success of the fabrication process. A variety of lead transfer methods are shown, and process details are discussed.

Keywords

References

  1. K.D. Wise, K. Najafi, 'Microfabrication techniques for integrated sensors and microsystems,' Science, 254, Nov. 29, 1991 https://doi.org/10.1126/science.1962192
  2. C.S. Sander, J.W. Knutti, J.D. Meindl, 'A monolithic capacitive pressure sensor with pulse-period output,' IEEE Trans. on Electron Devices, ED-27 (5), May 1980 https://doi.org/10.1109/T-ED.1980.19958
  3. J. Ji, K.D. Wise, 'An implantable CMOS analog signal processor for multiplexed microelectrode recording arrays,' Tech. Dig., IEEE Solid-State Sensor and Actuator Workshop, Hilton Head, 1990, pp. 107-110 https://doi.org/10.1109/SOLSEN.1990.109831
  4. Y.B. Gianchandani, K.J. Ma, and K. Najafi, 'A CMOS dissolved wafer process for integrated p++ microelectromechanical systems,' Proc., IEEE International Conference on Solid-State Sensors and Actuators (Transducers '95), Stockholm, Sweden, June 1995, pp. 79-82 https://doi.org/10.1109/SENSOR.1995.717093
  5. K. Ma, K. Najafi, 'A new capacitive electro-chemical etch-stop technique,' Proc. IEEE International Workshop on Micro Electro Mechanical Systems (MEMS) 1994, Oiso, Japan, pp. 158-163 https://doi.org/10.1109/MEMSYS.1994.555616
  6. Y.B. Gianchandani, K. Najafi, 'Batch-assembled multilevel micromachined mechanisms from bulk silicon,' lOP Journal of Micromechanics and Microengineering, vol. 2, pp. 80-85, 1992 https://doi.org/10.1088/0960-1317/2/2/003
  7. Y.B. Gianchandani and K. Najafi, 'Scanning Thermal Profilers with Integrated Sensing and Actuation,' IEEE Transactions on Electron Devices, 44 (11), Nov. 1997, pp. 1857-68 https://doi.org/10.1109/16.641353