電容式液態傾角感測器

Abstract

微機電系統是一個結合多重領域的科技平台，因此可應用的層面相當廣泛。傾角感測器應用於檢測水平位置，對於土木建築、機械工作平台以及攜帶式電子產品都是一不可或缺的儀器。本研究利用微機電系統之設計及製程技術，設計及製造一新式傾角感測器。而感測器的製作，首先於玻璃基板上利用SU-8光阻製作上蓋結構，並利用CMOS技術製作感測電容以及感測電路，再使用上蓋結構與IC晶片黏合，製作出一封閉腔，並在其內置入感測液體，當感測液體由於元件傾斜而運動時，會改變IC晶片上感測電容的電容值，此時感測電路會把電容變化量轉變為電訊號輸出，如此便能夠藉由電訊號的數值來判斷傾斜的角度以及方向。 本研究所提出的傾角感測器利用感測液體運動的方式來改變感測電容的電容值，由於感測液體是靠重力而運動，因此能夠有效避免因外在因素，如溫度、電磁力、電波等變化而影響傾角感測器的準確度。 而利用微機電製程技術來製作傾角感測器，除了使用較簡單的設計方式來達到高精度的角度感測外，相較於相關文獻所提出的感測器結構更為簡單，且更可應用於批次製造以降低成本。

Micro-Electro-Mechanical System (MEMS) is the technology platform that integrates various fields. The tilt sensor can be used to measure the level of inclination in fields of civil engineering, mechanical, portable electronic devices and many others. The sensor is designed and fabricated by using MEMS technology. The sensor was first fabricated on a glass substrate using SU-8 photoresistor to make the top structure. CMOS technology was used to fabricate the sensing capacitance and the sensing circuit. Then the top structure was bonded with the IC chip to make a closed cavity with injected sensing liquid. When the sensing liquid is moved by the tilt, it will change the the sensing capacitance on the IC chip. The sensing circuit will output an electrical signal. So we can determine the angle of inclination and the direction by the value of the electrical signals. The tilt sensors in this research use a sensing liquid movement to change the capacitance of the sensing capacitor value. The sensing liquid is move by gravity, and therefore be able to avoid effect due to external factors such as temperature, electromagnetic force, waves such changes may affect the sensitivity of the inclination sensor.