Assembly of electronics and optelectronics with optoelectronic tweezers

Abstract

Optoelectronic Tweezers (OET) is a relatively new micro- and nanoscale manipulation technique that takes advantage of both optical tweezers and dielectrophoresis (DEP). Based on light induced dielectrophoresis (LIDEP), the virtual electrodes which are created by light allow continuous control and massively parallel manipulation over a large operational area with a low required optical power and a high accuracy. In this work, we demonstrated the use of OET to manipulate micro-objects including silver-coated PMMA microspheres, solder beads, carbon nanotubes and part of GaN micro-LEDs. The prerequisites of building functional circuits with OET including electrical connection and component manipulation have been investigated as well. We proposed a feasible method for creating electrical connection including assembly, freeze-drying and step-by-step melt. Current-voltage characteristic shows a low resistance of 11.6 Ω, which proves the capacity of OET in creating good electrical connection. Accuracy of assembly has been examined both qualitatively and quantitatively, which indicates a way to choose an appropriate light pattern size in assembly. We proposed a quantitative definition of accuracy and found a linear relationship between light pattern diameter and accuracy. The highest accuracy we achieved is 0.8 ± 0.1 μm with 60 μm diameter light pattern for 45 μm solder beads. The maximum speed of 45 μm solder bead we achieved is 2800 μm/s, corresponding to a DEP force of 3.27 nN which is much larger than optical tweezers (pN level).