微梁与基底间的毛细粘附作用

Capillary Adhesion between the Micro Beam and Its Substrate

在表面微型机械结构的制造过程中,强的毛细相互作用常常使得组成这些结构的微桥、微梁与基底粘附而导致失效。而在微尺度实验中,微桥与微梁又是微尺度材料常数和性能检测的常用的试件样式,如果实验中加载端与被检测的微尺度试件发生毛细粘附,将直接影响检测数据的准确性。本文应用微悬臂梁试件,讨论微梁与基底间的毛细粘附作用,并通过能量原理计算其粘附力的大小和试件几何尺寸、粘附面距离、粘附液体特性之间的关系。最后应用微散斑干涉,检测粘附平衡态时微桥和微梁的粘附力以及由毛细粘附所导致的弯曲变形,并与理论计算结果进行比较。

In the process of manufacturing the micro mechanical structure, strong capillary effect often makes the micro beam adhere to the substrate, which leads to device failure. In the micro scale experiments, micro beam is often used as the specimen to test the micro scale material constants and performances, so if the loading end adheres to the specimen in the experiments, the accuracy of the obtained data will be greatly influenced. In this paper micro cantilever beam specimen is used to discuss the capillary adhesion between the micro beam and its substrate. The relationship of the magnitude of the capillary force with the size of the specimen, the distance between the micro beam and the substrate, and the characteristic of the adhering liquid are obtained. Micro speckle interferometry is employed to detect the deformation of the micro beam in the equilibrium and the experimental results are compared with the theoretical prediction.