Reliable Metallization Process for Ultra Fine Line Printing

Abstract

In this paper we present an approach to achieve both 100mg paste deposit on a c-Si solar cell and efficiency gains with no impact on peel strength at extremely narrow finger widths. Using the double print process with suitable pastes and screens we demonstrate an 0.18% absolute efficiency gain and 20% paste saving over the standard process. This benefit is correlated to the finger width reduction from 63μm to 47μm, leading to an increase in Isc and Voc, due to the reduced recombination area under the metal contacts. The peel strength is also shown to increase from 1.5N to 3N for the same busbar thickness, when different paste compositions for the DP process are used. We also show screen lifetimes above 30k prints in production, with a stable process in terms of efficiency gain and paste saving.