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.