Dielectric Patterning Using Aerosol Jet Printing

Abstract

A method for spatially selective etching of dielectric layers using an aerosol jet printer is described. The method, referred to as direct etching, was first implemented using inkjet printing. This article reports on the adaption of the method to operate on an ‘Optomec’ aerosol jet printer in order to increase patterning resolution and processing throughput, as required for commercial photovoltaic applications. It is demonstrated that the etching process can be tailored to different applications by varying the processing parameters, such as the gas flow rates, platen movement speed and number of printing passes. The results presented in this article show that grooves as narrow as 20 μm can be etched in dielectric layers that are commonly used for passivation of commercially produced silicon solar cells. Accurate alignment enabled by the ‘Optomec’ aerosol jet printer allowed etched patterns to be formed in pre-patterned surfaces, a property that may find application in a number of selective-emitter solar cell designs which currently use aligned screen printing for metallization. In addition, a method of etching point openings for metal contacts for enhanced rear surface passivation is presented and discussed.