以靜電式平面梳狀致動器驅動之旋轉平台及一維垂直電熱致動器之量測與分析

Measurements and Analyses of the Electrostatic In-plane Comb-drive Rotational Platforms and 1-D Vertical Electrothermal Actuators

賴仁傑(Ren-jie Lai)

指導教授 ： 蔡睿哲

國立臺灣大學/電機資訊學院/光電工程學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.10547

摘要

過去微機電(MEMS)技術的應用範圍，包括汽車安全氣囊的自動撞擊感測器、噴墨印表機噴頭、壓力感測計、微陀螺儀等等。近年隨著CMOS技術發展，微機電技術之相關應用產業已進入消費性電子等多樣化領域。

一般微致動器的致動方法常用的有：靜電驅動、熱變形、壓電變形、電磁驅動等等，其他特別的物理機制方式也有，例如水珠、摩擦力等等。而運動方式也分為線性運動、彎曲、擺動、旋轉等等。

在本論文中首先介紹利用MetalMUMPs製程製造一種以靜電方式驅動的平面梳狀致動(in-plane comb-drive)一維旋轉平台。此旋轉平台的轉軸位於平台底部中央，當側向靜電力產生時此平台會因為底部有支點的關係而傾倒，以致達成旋轉的條件。得到實驗結果為當施加105V的電壓時平台的旋轉角度可達2.870.

論文中提出的另一種設計是垂直方向偏轉的電熱致動器。不同於以往以單材料(uni-material)為結構或者是不同材料結合而成的雙層結構(bimorph)，我們設計了分隔式、多種材料結合而成的電熱致動器，其中上層之鎳金屬具有較大的熱膨脹係數(CTE)以及較小的比熱，中間層是空氣視為gap，下層的多晶矽(Polysilicon)當做電流通路並且被氮化矽(Si3N4)包覆住。當電流通過整個結構時鎳金屬會產生垂直向下的彎曲。經過量測多組不同設計尺寸的元件得到最小的驅動電流在0.82mA時，致動器頂端即可達到25μm向下的位移，消耗的功率為10.58mW.

關鍵字

微機電 ； 靜電致動器 ； 電熱致動器 ； 平面梳狀致動器 ； 多層材料

並列摘要

The application range of Micro-Electro-Mechanical Systems (MEMS) technology, including the sensor using in airbag deployment systems for modern automobiles, inkjet-printer cartridges, pressure sensor, micro-gyroscopes, etc.. In recent years, the applications of MEMS technology have covered the consumer electronics due to the development of CMOS technology.

The actuation methods for typical micro-actuator include electrostatic driving, electrothermal deformation, piezoelectric deformation, and electromagnetic driving. Other actuating mechanisms such as droplet and friction have also documented. The motion types can be divided into bending, oscillating, rotation, and linear motion.

We present a 1-D rotational platform made by MetalMUMPs process and which is driven by electrostatic in-plane comb-drive actuators. The rotation axis locates on the middle of the bottom of the platform. When lateral electrostatic force is applied, the platform will cause “tilt” due to the created pivot on the bottom of the platform so that the rotational platform is accomplished. An out-of-plane rotational platform with in-plane electrostatic comb-drive actuators is presented in this thesis. A rotational angle of ±2.87o is achieved at a static driving voltage of 105V.

Another design which is proposed in this thesis is the vertical electrothermal actuators. We design the electrothermal actuators in the form of separated multi-materials which are different from uni-material and bimorph. Among them, the upper nickel metal provides higher coefficient of thermal expansion (CTE) and lower specific heat. The middle layer of the structure is air gap. Silicon nitride is used to be the torsion springs that connects to the movable nickel combs and rotational platform. Polysilicon enclosed in the nitride springs provides the electrical feed-through for the movable combs. While the electric current passes through this circuit, the tip of the nickel metal will induce downward bending. After measuring several devices in different design parameters, the actuator tip displacement of 25 μm is achieved in driving current of 0.82mA.

並列關鍵字

MEMS ； electrostatic actuator ； electrothermal actuator ； in-plane comb-drive actuator ； multi-material

參考文獻

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