A Study of Thermally Actuated Microvalve and Micro Flow Sensor

• Main Authors: Wen-Hua Tsai, 蔡文華
• Other Authors: Kow-Ming Chang
• Format: Others
• Language: en_US
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/45148591607591771301

碩士 === 國立交通大學 === 電子工程系 === 87 === Thermally actuated microvalves and micro-flow sensors are very potential in the field of MEMS. They are small devices with large actuation range, low power consumption and precise sensing ability. Besides, they can be integrated to construct a micro flow control system. The main structure of a microvalve is a sandwich diaphragm which consists of Pt, SiO2 and Si layers. The microvalve buckles due to the different thermal expansion of these materials. The microvalve is controlled by an input voltage to the platinum heater. In the micro-flow sensor, the sensing mechanism is that the resistance of a material varies with the change of temperature. This variance is called the temperature coefficient of resistivity (TCR). We also choose Pt as the sensing material owing to its high TCR. In addition, it is easy to integrate the micro-flow sensor with the microvalve by the same manufacturing processes. In this thesis, we propose the mechanisms and design considerations of the microvalve and the flow sensor. Fabrication process and results are discussed. Some suggestions are also given to promote the performance of the system.