Improved adhesion for plated Solar cell metallisation

Experts predict that copper plated metal contacts will eventually become the dominant metallisation for silicon wafer-based technologies once several key issues are solved. Of particular importance is the adhesion strength and hence durability of such plated contacts with many of the largest cell manufacturers currently nervous about considering such metallisation for large-scale manufacturing due to concerns in this area. A new approach for enhancing the adhesion strength for plated contacts involves establishing laser-machined anchor points in the silicon surface which when plated act to enhance both the ohmic contact and the mechanical adhesion strength for the metallisation. Cells manufactured on a production line using this innovation typically lose 0.1% in efficiency in absolute terms relative to identically manufactured cells that do not use the anchor points. BP Solar´s Saturn cells using a similar approach have demonstrated that such plated contacts are at least as durable if not more durable than screen-printed contacts installed at the same time 20 years ago.