微機電電容式麥克設計與製造

本文完成多層堆疊電容式麥克風的設計、製作與特性分析。以矽製程微機電系統技術為基礎，完成微結構相關特性模擬分析後，設計不同尺寸與多樣式結構的電容式麥克風，相關電容式麥克風製程由MEMSCAP協助完成。本文基於最佳化設計之結果完成晶片尺寸的設計、利用半導體製程製作以及電腦來進行模擬分析對照，最後再進行封裝及性能測試，以不斷改善麥克風設計來適應工業界嚴格之需求。此外，關於電容式麥克風特性的量測。在雷射都卜勒的動態檢測中，可以明顯的觀測橫隔薄膜受到聲壓而產生的規律振動，其振動的最大位移量約在１微米之間，在頻率響應的量測中，可以發現雜訊對其元件的干擾影響，在經由治具的改善與放大器的增益輸出後，應可以得到一個完整訊號的頻率響應曲線，在取樣頻率1 kHz時，約可得到-80 dB/Pa的增益輸出（ref. to 0.1mV/Pa）。經由量測結果證實，此微電容式麥克風簡單的微機電結構與高靈敏度的特徵是能夠被預測的。未來工作將研究改善犧牲層蝕刻的長時間釋放技術，並調整元件微機電結構設計，使具高靈敏度的薄膜應力變化感測效能，以期能建立微感測器相關技術於日後的應用中。

關鍵字

薄膜；崩潰電壓；麥克風；微機電

並列摘要

The multi-layer stacking capacitive types of microphones are designed and fabricated based on theoretical analysis, simulations and silicon-based MEMS fabrication technology. The microphones in different physical sizes and functional structures are designed on the same chip. Micro-fabrication of the micro-microphones has been performed by the MEMSCAP Company. The MEMS microphone had been produced based on the optimum design and analysis. Two approaches are adopted in experimental validation --- one under static input voltage while another subjected to vibratory sound in wide frequency range. In the case with 6 Pa sound pressure applied to the membrane, the largest displacement of 1 m over the entire membrane is measure by a laser Doppler vibrometer, and furthermore pull-in phenomenon is present with acquisition of corresponding pull-in voltage and membrane deflection. In the second case with vibratory sound as the excitation, the frequency responses are obtained with moderate levels of noise present, giving less satisfactory sensitivities of the manufactured microphone. This is probably due to high residual stress remained inside the membrane. This residual stress is primarily caused the heat release from bulk micro-machining etching process on the backplate. When the sampling frequency reaches 1 kHz, gain output is about -80 dB/Pa (ref. to 0.1mV/Pa). Future works should be focused on developing the fabrication process to reduce residual stress for improving long-term sacrificial layer release etching technology and to adjust microstructures for compensating non-specific effects reduced film stress variations.

並列關鍵字

MEMS ； microphone ； membrane ； pull-in

參考文獻

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微機電電容式麥克設計與製造

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