Direct Laser Patterned Electroplated Copper Contacts for Interdigitated Back Contact Silicon Solar Cells

Laser patterning of seed layers for Cu electroplated interdigitated contacts on Ni/a-SiN
_x
:H/Si substrates is presented. Damage was controlled by varying the laser conditions. Cu growths shorted the contacts due to conductive residues in the scribe lines, but were attenuated with pre-deposition etching yielding electrically-isolated plated fingers. Parasitically-plated Cu stripes were now observed in laser cuts, postulated due to Cu nucleation from high current densities at pinholes originating from laser and etch damage to the resistive a-SiN
_x
:H. While a promising approach for contact processing, laser conditions must be carefully optimized to minimize substrate damage.