Title :
Surface-Tension-Driven Self-Assembly of 3-D Microcomponents by Using Laser Reflow Soldering and Wire Limiting Mechanisms
Author :
Lei Yang ; Wei Liu ; Chunqing Wang ; Yanhong Tian
Author_Institution :
Sch. of Mater. Sci. & Eng., Harbin Inst. of Technol., Harbin, China
Abstract :
This paper proposes a surface-tension-driven self-assembly method for manufacturing highly 3-D microstructures in microelectromechanical systems (MEMS). By using laser reflow soldering, various MEMS microstructures, even including the thermal-sensitive components, are able to be effectively assembled. Moreover, an energy-based numerical model is established for predicting the equilibrium geometry of a self-assembled structure. Based on the calculated results of energy and torque, an analysis is carried out on the factors affecting the self-assembled equilibrium position. In addition, the self-assembly process is also investigated experimentally by fabricating a popped-up microstructure with two light-emitting diodes die. Experimental studies, combined with the modeling results, have demonstrated that the self-assembly angle can be controlled within ±2.5°. Furthermore, in order to enhance the precision of self-assembly, a novel low-cost wire limiter structure fabricated by the wire bonding process is presented, which reduces the assembly angle variation down to ±0.5°.
Keywords :
lead bonding; light emitting diodes; microfabrication; micromechanical devices; numerical analysis; reflow soldering; self-assembly; surface tension; 3D microcomponents; 3D microstructure manufacturing; MEMS microstructures; assembly angle variation; energy-based numerical model; equilibrium geometry prediction; laser reflow soldering; light-emitting diodes die; low-cost wire limiter structure; microelectromechanical systems; popped-up microstructure fabrication; self-assembled equilibrium position; self-assembled structure; self-assembly angle; surface-tension-driven self-assembly method; thermal-sensitive components; wire bonding process; wire limiting mechanisms; Assembly; Light emitting diodes; Micromechanical devices; Microstructure; Self-assembly; Surface treatment; Torque; 3-D microcomponents; laser reflow; microelectromechanical systems (MEMS); self-assembly; surface tension; wire limiter;
Journal_Title :
Components, Packaging and Manufacturing Technology, IEEE Transactions on
DOI :
10.1109/TCPMT.2012.2221126