| Summary: | 碩士 === 國立中興大學 === 精密工程學系所 === 99 === In this thesis, we have presented a high sensitive miniature ribbon microphone fabricated with a combination of semiconductor manufacturing and micro-electro-mechanical system techniques. For the circuit design within ribbon microphone, the dual induction circuit was introduced in order to amplify the signal from induction coil cutting magnetic field. Furthermore, the vibration velocity and sensitivity of diaphragm were significantly improved by altering its shape as a consequence of releasing diaphragm strain. The miniature ribbon microphone thus possesses of a higher sensitivity.
SU-8 1040 was used as a main material of the diaphragm in miniature ribbon microphone since it was more compliant to the lithophotography that we implemented in this study. Another advantage of using SU-8 1040 is a lower process temperature, which reduced the extrinsic stress induced by the difference of thermal expansion coefficient between diaphragm and substare. The dimension of dual induction circuit was 17 mm×3 mm×0.003 mm for rectangular shape. With this design,the vibration rate reached 4.85 um/s. The frequency response of miniature ribbon microphone was -42.6 dBV/Pa (@1k Hz), corresponding to a sensitivity of 7.41 mV/Pa.
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