致動器(Actuator)為微機電系統元件之一，其驅動方式包含靜電驅動、壓電驅動、電磁驅動、電熱驅動及記憶合金。電熱式致動器因具有低操作電壓、製程容易、與積體電路相容等特性，且可應用陣列方式增加其位移與輸出力量。因此，在應用上具有相當大的發展空間。

本研究提出以彎曲樑結構製作熱致動器，此彎曲樑結構可避免V型致動器水平方向挫曲之缺點。利用有限單元分析軟體ANSYS計算出具有最大位移及微小應力之結構。此最佳尺寸為寬度5μm、曲率半徑3,000μm之彎曲樑。其主要結構材料包含矽基材(Silicon Substrate)、鋁電極(Aluminum Pad)及作為導電熱源之多晶矽(Polysilicon)。熱致動器結構之分析流程以熱力學為基礎，計算出結構正確之熱對流係數，代入有限單元分析軟體ANSYS，求得正確之溫度分佈。再以此溫度分佈作為結構之負載，可得到結構精確之力學行為。以本研究之模擬方法所求得結構之位移與文獻中之量測結果相比較，其誤差在10%以下。

An actuator is a component of the Micro-Electro-Mechanical System (MEMS). The ways to drive actuators include electrostatic driving, piezoelectricity driving, electromagnetic driving, electro-thermal driving and shape memory alloy. Electro-thermal actuators have such advantages as lower input voltage needed, integrated-circuit manufacturing technology used. Furthermore, both types of actuators can be arrayed to increase its displacement and output force. Therefore, the actuators have sizable development space in application

We choose curve-beam as the structure, because the structure can avoid horizontal buckle in the V-type actuators. A finite element software (ANSYS) was used to solve the 3D electro-thermo-mechanical problems. We compute the optimum dimension that has the maximum displacement and minimum stress. The optimum structure of actuator is 5μm wide and 3,000μm in radius. The structure materials include Silicon Substrate, Aluminum Pad and Polysilicon. The analysis processes are based on thermodynamics, so we can compute the accurate heat transfer coefficient and get accurate temperature distribution by using ANSYS. Then we can obtain accurate mechanical behaviors, and compare them with the literature. Its error is under 10%.

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