Ultrasonic Bonding of Aluminum Ribbons to Interconnect High-Efficiency Crystalline-Silicon Solar Cells

Abstract Next-generation, crystalline-silicon solar cells might use different metallization concepts compared to current state-of-the-art cell designs. One specific design uses a thin aluminum back layer created with a physical vapor deposition process. In the solar industry, there is no reliable, cost-effective method of directly connecting metallic ribbons to such an aluminum layer to create cell strings. In the semiconductor industry ultrasonically bonding aluminum ribbon to the aluminum metallization of power semiconductors or high-volume production is a well-established process. This paper describes adapting ultrasonic ribbon bonding and the equipment used in the semiconductor industry to interconnect crystalline-silicon solar cells.