Skip to main content

Influence of a chip scale package on the frequency response of a MEMS microphone

Abstract

This paper describes the influence of a chip scale MEMS package (CSMP) on the acoustic behaviour of a silicon microphone. The influence was calculated using an electro-mechanical–acoustical equivalent circuit. Standard packaging of microphones using die bonding and wire bonding leads to a large front volume which acts as a Helmholtz resonator. This can dramatically influence the frequency response of the microphone system by adding a second resonance. In the worst case this second resonance is in the acoustic frequency range, thus degrading its performance in an unacceptable way. In case of the CSMP only a small front volume is generated between the substrate and the flip-chipped microphone chip. Thus the resonance step-up is very small compared to standard packages. Furthermore the frequency response can be flattened by optimizing the geometry of the small sound holes in the substrate. By choosing an appropriate geometry of these sound holes the package can act as a low pass filter where the cut-off frequency can be placed to the desired value of the acoustic spectrum.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11

References

  • Dehé A (2007) Silicon microphone development and application. Sens Actuators A 1333:283–287

    Google Scholar 

  • Feiertag G, Leidl A, Winter M (2009) Packaging of MEMS microphones. Proceedings of SPIE 7362-12

  • Füldner M (2004) Modellierung und Herstellung kapazitiver Mikrofone in BiCMOS-Technologie. Dissertation, Universität Erlangen-Nürnberg

  • Jogwich A (1974) Strömungslehre. W. Girardet, Essen

    Google Scholar 

  • Kühnel W, Hess G (1992) A silicon condenser microphone with structured back plate and silicon nitride membrane. Sens Actuators A 30:251–258

    Article  Google Scholar 

  • Li ZX, Du DX, Guo ZY (2003) Experimental study on flow characteristics of liquid in circular microtubes. J Microscale Thermophys Eng. doi:10.1080/10893950390219083

  • Prophet G (2008) MEMS enable multi-microphone consumer products. EDN Europe 12:30–34

    Google Scholar 

  • Scheeper PR, van der Donk AGH, Olthuis W, Bergveld P (1994) A review of silicon microphones. Sens Actuators A 44:1–11

    Article  Google Scholar 

  • Sessler GM (1987) Electrets. McGraw-Hill, New York

    Google Scholar 

  • Skvor Z (1967) On the acoustical resistance due to viscous losses in the air gap of electrostatic transducers. Acustica 19:295–299

    Google Scholar 

  • Timoshenko S (1959) Theories of plates and shells. McGraw-Hill, New York

    Google Scholar 

  • Zollner M, Zwicker E (1993) Elektroakustik. Springer, Berlin

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Matthias Winter.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Winter, M., Feiertag, G., Leidl, A. et al. Influence of a chip scale package on the frequency response of a MEMS microphone. Microsyst Technol 16, 809–815 (2010). https://doi.org/10.1007/s00542-009-0994-z

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00542-009-0994-z

Keywords

  • Counter Electrode
  • Acoustic Resistance
  • Helmholtz Resonator
  • Radiation Impedance
  • Mechanical Mass