The main objective of this work is to adapt Laser Induced Forward Transfer (LIFT), a well-known laser direct writing technique for material transfer, to define metallic contacts (fingers and busbars) onto c-Si cells. A layer of a commercial silver paste (viscosity around 30-50 kcPs), with thickness in the order of tens of microns, is applied over a glass substrate using a coater.. The glass with the silver paste is set at a controlled gap over the c-Si cell. A solid state pulsed laser (532 nm) is focused on the glass/silver interface producing a droplet of silver that it is transferred to the acceptor substrate. The process parameters (silver paste thickness, gap and laser parameters -spot size, pulse energy and overlapping of pulses) are modified and the morphology of the voxels is studied using confocal microscopy. Long lines are printed with a scanner and their uniformity, width, and height are studied. Examples of metallization of large areas (up to 10 cm x 10 cm) over c-Si cells are presented.

Date Published: 12 March 2015
PDF: 7 pages
Proc. SPIE 9351, Laser-based Micro- and Nanoprocessing IX, 93510B (12 March 2015); doi: 10.1117/12.2080092

Published in SPIE Proceedings Vol. 9351:
Laser-based Micro- and Nanoprocessing IX
Udo Klotzbach; Kunihiko Washio; Craig B. Arnold, Editor(s)