声学 MEMS Microphone

Measurement through the back-plate

A MEMS microphone is composed by a diaphragm vibrating between on or two holed back-plates. Measurement of topography and vibration modes of each the diaphragm is challenging :

  • Diaphragm is measured through  the back-plate. High lateral resolution is required
  • The thin 1 um back-plate silicon membrane is transparent for visible and near IR illumination. UV laser source is required

Description

  • Diaphragm diameter : 100 μm
  • Magnification : 20x
  • Lateral resolution : 0.5 μm
  • Excitation frequency : 1 kHz
  • Instrument : DHM R-1000 equipped with UV laser source

Vibrations measurement

The amplitude vibration map shows the diaphragm vibrations when the microphone is excited as a speaker by the stroboscopic unit at 1 kHz. The first vibration mode of both diaphragm is represented.

Amplitude vibrations map @ 1kHz