Tra.Q — Laser marking for single wafer identification — Production experience from 100 million wafers

Single wafer identification is a mandatory element of a modern solar cell production [1]. It accelerates the efficiency roadmap of the solar cell and fosters the cost reduction roadmap of the fabrication. The laser marking concept Tra.Q creates an individual code on each and every wafer. This makes process optimization and quality control easier and faster. The solar cells are 100% traceable along the whole value chain [2-4]. Q-Cells has a broad experience of meanwhile 100 million solar cells, being fabricated in the Thalheim manufacturing line. A large statistical database is available. Typically, the code for the individual tracking is engraved onto the bare wafer before the manufacturing process. The big benefits of the single wafer identification are (a) faster learning in production, (b) steeper ramp curves for the introduction of innovations, (c) improved quality control of materials and of products from the suppliers, (d) enhanced transparency to the customer. The single wafer identification helps to make root cause analysis easier and faster and to nail down the key issues in a particular manufacturing site.