Atotech, an MKS brand, offers electroplating processes using nickel and copper as alternatives to conventional silver screen-printed contacts
The nickel layer acts as a contact interface and diffusion barrier, while copper forms the main conductive fingers and busbars
Tin and silver are offered as alternative final finishes, providing solderable surfaces for cell interconnection
Atotech, a brand of US-based MKS Inc., offers electroplating processes as an alternative to mainstream screen printing. This approach uses nickel and copper as primary materials, plating Ni/Cu/Sn or Ni/Cu/Ag stacks for metallization.
Copper is a lower-cost, more abundant conductive material, but it requires a barrier or surface layer to ensure reliable electrical contact and protect the cell. MKS’s process uses a sequence of surface pretreatment, nickel plating, copper plating, and a final tin- or silver-plating step.
Nickel is the first layer that is plated onto the silicon surface, forming an interface between silicon and the subsequent copper contact layer. It also acts as a diffusion barrier, helping prevent copper from migrating into the silicon. MKS offers its Nimate PV process for this stage. Copper is then plated over the nickel layer to form the main conductive fingers and busbars to support electrical conductivity. The company highlights the ductility and low-stress composition of the plated copper contacts as properties that help withstand mechanical stress. Its CupraCid PV family is designed for copper plating at current densities ranging from 2 to 25 A/dm².
These copper contacts receive a final surface finish to support cell interconnection and protect the metal. One option is tin plating, which provides a solderable surface that acts as a protective layer against environmental exposure. MKS lists Stannacid PV for standard tin plating and Niveostan PV 20 for high-speed tin deposition.
Alternatively, silver can be deposited as a final capping layer. According to the company, this can be applied through immersion or electrolytic plating and provides a surface suitable for soldering. The company offers its Argalux PV process for this application.
MKS also positions its plating processes for different cell technologies and designs. The approach is intended to provide an alternative to conventional silver screen printing, with copper being the key element of the contact structure.
