Massively parallel low-cost pick-and-place of optoelectronic devices by electrochemical fluidic processing

We describe a novel electrochemical technique for the nonlithographic, flui dic pick-and-place assembly of optoelectronic devices by electrical and opt ical addressing. An electrochemical cell was developed that consists of ind ium tin oxide (ITO) and n-type silicon substrates as the two electrode mate rials and deionized water (R = 18 M Omega) as the electrolytic medium betwe en the two electrodes. 0.8-20-mu m-diameter negatively charged polystyrene beads, 50-100-mu m-diameter SiO2 pucks, and 50-mu m LED's were successfully integrated upon a patterned silicon substrate by electrical addressing. In addition, 0.8-mu m-diameter beads were integrated upon a homogeneous silic on substrate by optical addressing. This method can be applied to massively parallel assembly (>1000 x 1000 arrays) of multiple types of devices (of a wide size range) with very fast (a few seconds) and accurate positioning. (C) 2000 Optical Society of America OCIS code: 230.0250.