微機電系統中微熱致動器具有輸入電壓低、產生位移大、製程簡易等優勢，典型微熱致動器以材料受熱產生形變量，根據位移的方向，分為同平面(in-plane)與出平面(out-of-plane)熱致動器。相較於同平面熱致動器，出平面熱致動器在製程上較困難、相關文獻較少，本文以鋁薄膜V型樑結構為元件主體，利用薄膜結構及挫曲機制達到出平面方向的形變，量測在出平面方向的位移量。 利用有限元素法模擬元件在施加電壓下之電流分佈、溫度變化與形變量。結果顯示微熱致動器在低電壓下，結構產生水平位移；在高電壓下，熱膨脹形成壓縮力，當壓縮力超過臨界負載後結構發生挫曲變形，造成出平面方向位移。V型樑結構樑寬度20 μm、薄膜厚度500 nm在溫度56℃發生挫曲，出平面位移量為16 μm。根據模擬結果設計元件結構，利用半導體製程技術使用蒸鍍方式沉積500 nm鋁薄膜、定義V型樑圖形，以非等向性濕蝕刻矽完成V型樑結構釋放。將製備完成之元件以全域性加熱，利用雷射位移計量測在溫度150℃時，出平面位移量為98 μm；以區域性加熱在輸入功率為0.01 W時結構溫度為146℃，觀察到出平面的位移量為6 μm，量測結果在出平面位移量有差異性，因製程不穩定造成元件缺陷。 ;In micro-electro-mechanical system, micro-thermal actuators have the advantages of low input voltage, large displacement and simple fabrication process. Typical micro-thermal actuators are driven by material expansion. Accord to the actuation direction, it can be divided into the in-plane and out-of-plane thermal actuators. Compared with the in-plane actuators, the out-of-plane actuators have less investigated and are difficulty to fabricate. This study takes the V-beam structure as the main component, use the thin film structure and buckling to achieve the out-of-plane deformation, and measure the displacement in the out-of-plane direction. The finite element method is used to simulate the current density, temperature, and deformation of the device. The results show that the micro-thermal actuators have horizontal displacements at low voltage, and cause buckling deformation due to the excess compressive force over the critical load at high voltage, causing the displacement in the out-of-plane direction. The V-beam structure with the beam width 20 μm and thickness 500 nm buckles at the temperature of 56℃ and achieve 16 μm displacement in out-of-plane direction. Based on the simulation results, the actuator is fabricate using semiconductor fabrication techniques. A 500 nm aluminum film is deposited by vapor deposition, followed by lithography and anisotropic wet etching to generate the V-beam structure. The measurement results show a 98 μm out-of-plane displacement at the global heating temperature of 150℃ by laser displacement meter. The local heating of 0.01 W cause a displacement of 6 μm at 146℃. The difference in the measurement results is due to the structure defects of process instability.
