基于表面张力的复合微组装技术研究.

Micro-assembly plays an important role in the integration of MEMS, stretchable electronics, and microsensors. However, in micro and nano world, due to the scaling law, the body force such as gravity is not dominant anymore, instead, surface forces such as surface tension and Van der Waals forces become more dominant, which causes a big challenge for micro-assembly, especially for releasing of micro parts. This paper proposes a hybrid micro-assembly method which combines the robotic micro-assembly technique and the surface tension driven self-alignment technique. The robotic micro-assembly technique is used to achieve fast positioning and surface tension driven self-alignment technique is used to achieve high precision alignment. A theoretical model is developed to estimate the surface energy and surface tension for self-alignment. The influence of the displacement bias and droplet volume on the surface free energy and surface tension are investigated using the model. The results show that the surface free energy and surface tension force increase as the volume of the droplet and placement bias increases. Experiments have been carried out to study the relationship between the volume of the droplet and the success rate of self-alignment. The results show that the success rate can reach 100 % when the volume of the droplet is larger than 30nL and less than 110nL and the placement biases are in the range of 50 µm to 500 µm. This proposed method takes the advantages of fast robotic micro-assembly technique and high precision surface tension driven self-alignment technique and provides a new method for integration of the MEMS and stretchable electronics. [ABSTRACT FROM AUTHOR]