Static and dynamic mechanical properties measurement of micro-nano metal thin film using cantilever beam deflection

• Main Authors: Peng-Chih Chen, 陳朋馳
• Other Authors: 林明澤
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/85056673008780622955

碩士 === 國立中興大學 === 精密工程學系所 === 98 === Microelectromechanical systems (MEMS) technologies are developing rapidly with increasing study of the design, fabrication and commercialization of microscale systems and devices. Continued growth of Microsystems technologies requires still further miniaturization, with a corresponding need to understand how length scales affect static and dynamic mechanical behavior of all the components. Accurate knowledge on the static and dynamic mechanical behaviors of thin film materials used for MEMS is important for successful design and development of MEMS. Here, a new technique for studying the mechanical behavior of thin metal films is presented. The test specimen was designed to deposit on a novel triangle shape “paddle” beam in order to provide uniform plane strain distribution. Standard clean room processing was used to prepare the sample. The sample dimensions are 20mm × 20mm, using a silicon substrate. The length of the triangular beam from the fixed end to the free end connected to the paddle plate is 3mm. The area of the paddle plate is 25mm2. The thickness of the silicon wafer is 250μm. The thickness of the cantilever beam is 40μm after etching. Sputter deposition was used to deposit the metal conduct layer onto the bottom surface. The tested thin film on the top surface can then be measured for its static and dynamic mechanical properties. The measurement system is custom design and the system set-up is design to measure beam deflection by either capacitance or a laser point reflection inside the vacuum chamber. It consists of the position sensor measurement and the deflection electrode. The measurement is made using a capacitance plate mounted on the PC board on top or a laser point reflected from the paddle plate surface into a position sensing detector (PSD). The static testing on the modulus measurements of Al thin films with different thickness was presented. The dynamic properties of Al thin film were also studied using the dynamic frequency response of the paddle structure generated by electrostatic force under different vacuum pressure were also demonstrated.