具有音源定位功能之中央支撐仿生式麥克風之製造與量測

Abstract

本論文中介紹製造與量測一具備聲源定位功能之中央支撐圓形振膜之混合仿生式微機電麥克風。此麥克風模仿了寄生蒼蠅耳朵的機制與酢漿草莖幹的支撐架構，並利用四層電鍍銅製程達成。以往的製程中由於振膜與基板間極小的空氣間隙，導致嚴重的黏附效應，因此多加了一dimple 層，來消除此黏附效應。其中，傳統中央支撐圓形振膜仿生麥克風為一萬向節式設計，為了比較特性，我們利用電鍍銅製程將兩種麥克風製造出並量測，結果顯示混合式仿生麥克風在敏感度上有36%的改善，亦即會有較好的聲源定向功能。藉由製造與量測，我們進一步驗證了混合式仿生麥克風，不但繼承了傳統萬向節式設計的好處，也提昇了聲源定位的敏感度，增加了微機電麥克風在助聽器應用上的潛力。

This paper presents the fabrication and measurement of a hybrid biomimetic MEMS microphone which is supported by a central-supported circular diaphragm for sound source localization. The microphone imitating the mechanism of the parasitoid fly’s ear and the supporting construction of clover stalk has been successfully fabricated using a four-layer copper electroplating process. A dimple layer has been added to eliminate the stiction effect resulted by smaller air gap which is a critical factor to ensure device reliability. Two kinds of central supported diaphragm designs in the biomimetic microphones which are the conventional gimbal-type and the hybrid one respectively have been fabricated and measured for performance comparison, the results indicate that the hybrid design has a superior ability in sound source localization, i.e. ~36% sensitivity improvements in comparison with that of the hybrid design. The fabrication further validates the hybrid structure can not only inherit the advantages from conventional gimbal-type design, but also promote sound source localization sensitivity for MEMS microphones with a potential application for hearing aid devices.