應用於人體脈搏感測之CMOS多層平行板電容式觸覺感測器

CMOS-Based Multiple Parallel Plate Capacitive Tactile Sensors for Human Pulse Sensing Application

柳峻琮(Jyun-Cong Liou)

指導教授 ： 田維誠

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.02032

摘要

本研究以互補式金氧半導體微機電系統（CMOS MEMS）製程設計電容式觸覺感測器，主要使用TSMC 1P6M 0.18 μm CMOS MEMS製程。特色為一感測結構內含有兩個感測電容，感測器由三個平行電極板與兩個可移動之空氣間隙組成；空氣間隙原先以鋁、鎢填滿，並於後製程中蝕刻除去，鋁金屬層與二氧化矽（SiO2）介電層構成感測器之結構體。感測器依電極幾何形狀主要分為方形以及米字形設計兩種類型，而方形設計依中央支柱尺寸又可細分為260 μm × 260 μm與200 μm × 200 μm。由探針施加壓力於感測器進行往復型之測試，量測所得感測器之上電容靈敏度以米字形設計4.96 fF/ mmHg最高，下電容靈敏度以中央支柱200 μm × 200 μm 之方形設計5.55 fF/ mmHg最高。人體脈搏量測中，量測得橈動脈之脈搏波形與壓力資訊之初步結果，證明具有發展成為非侵入式連續血液脈搏壓力感測器之潛力。

關鍵字

微機電系統 ； 互補式金氧半導體製程 ； 非侵入式 ； 電容式觸覺感測器 ； 脈搏壓力感測器

並列摘要

In this research, capacitive tactile sensors based on CMOS MEMS process were developed. Two sensing capacitors were integrated in one sensor structure for tactile sensing. The fabrication of sensor chips was based on the TSMC 1P6M 0.18 μm CMOS MEMS process. To realize two capacitors in one sensor, three parallel electrodes and two tunable air gaps were designed. The air gaps were initially filled with aluminum and tungsten and the metal filling would be removed in the wet etching process. The membrane electrode of the sensor consisted of aluminum and silicon dioxide. According to the geometry of the electrode, sensors were categorized into square-type and star-type designs. Two square-type designs were proposed; one design was with a larger central pillar with an area of 260 μm × 260 μm while the other design was with a smaller central pillar, with an area of 200 μm × 200 μm. The characterization of the sensors was obtained by a custom made testing system. It was measured that the maximum sensitivities of upper and lower capacitors are 4.96 fF/ mmHg for the star-type design and 5.55 fF/ mmHg for the square-type design with the 200 μm × 200 μm central pillar, respectively. In the human pulse measurement, preliminary radial pulse waveforms and blood pressure information were demonstrated successfully. It was demonstrated that our tactile sensors can be used for non-invasive continuous pulse pressure monitoring.

並列關鍵字

MEMS ； CMOS process ； non-invasive ； capacitive tactile sensor ； pulse pressure

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