Automatic microcircuit formation based on gold-coated SU-8 microrods via dielectrophoresis

To explore the application of the characteristics of metallic microparticles, alternating current electric trapping of the SU-8 microrods coated with a thin gold layer by the chemical approach is investigated. Positive dielectrophoresis is used to absorb the gold-coated SU-8 microrods at the edge of the parallel electrodes, thereby forming chains to connect the electrodes. This is a fast automatic microcircuit formation process. Moreover, a non-charged molecule is modified on the surface of the gold-coated SU-8 microrod, and the modified microrods are controlled by the alternating electric field to form a number of chains. The different chains between the parallel electrodes consist of various parallel circuits. In order to compare these chains with different electric surfaces, the impedances of the metallic and modified microrods are measured and compared, and the results show that the gold-coated microrods act as pure resistors, while the microrods functionalized by a non-charged molecule behave as good capacitors.