本研究提出了以CMOS-MEMS製程技術所製作之4×4電容式超音波感測器晶片。藉由將感測電路置於感測結構的下方，減少了拉線進而降低電路之寄生電容，有較好的訊噪比，同時也提高了面積利用效率。全新的晶片只要透過濕蝕刻釋放Metal 3，並以Parylene封閉蝕刻孔，簡單的兩個後製程步驟即可供實驗量測使用。單一感測器面積為280μm×280μm以9個(3×3)直徑60 μm的圓形薄膜並聯而成，總電容值為312.2 fF。感測陣列則是以16個(4×4)單一感測器所組成，總感測面積約1120μm×1120μm。實驗結果發現感測陣列中的16個感測器，均成功在水中收到5 MHz超音波探頭所發出的訊號，並在適當的量測條件下可達到數百mV的輸出。在光聲成像方面，運用馬達二維掃描物體的方式，單一感測器成功地呈現出6 μm碳纖維的3D影像，感測陣列則成功地呈現頭髮的3D影像。

This study proposed a 4 × 4 capacitive ultrasonic sensor chip produced by CMOS-MEMS process technology. By using the sensing circuit placed at the bottom of the sensor structure, the routing interconnect is reduced, so is the parasitic capacitance. It had a better signal-to-noise-ratio, but also improved the efficiency of area utilization. The structures were released through wet etching (Metal 3), and sealed by using the Parylene. Nine membranes, each with an inner diameter of 60 μm, formed a single detection unit with the area of 280 μm × 280 μm and the capacitance value of 312.2 fF. The sensor array is composed of 16 (4 × 4) sensors with a total area of about 1120 μm × 1120 μm. The experimental results show that the 4 × 4 sensor array can successfully receive the signals of 5 MHz ultrasound in the water, outputs of hundreds of mV can be measured under appropriate measurement conditions. 2D large-aperture arrays were emulated by 2D mechanical scanning of a single sensing element or 16 (4 × 4) sensing elements. The 3D photoacoustic images of a carbon fiber and a hair were successfully produced.

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