Low cost Rear Ag paste using doping silver plated-coated Copper and Tin powder under N2 protection firing

Low cost Rear Ag paste is made by silver plated-coated Copper and Tin powder to replace part of pure Ag powder in the paste to reduce the cost of solar cell manufacture and also improve the adhesion of the solar cell busbar. The key issue to use Ag coated copper and tin is the oxidization of cooper and tin during the drying and firing process which will reduce the solderability and adhesion by using this system. We use N2 protection during drying and firing process to prevent the oxidization of cooper and tin. Therefore, the solderability and adhesion has been increased a lot to achieve the industry testing standard. Also Rs reduction is also a big achievement for this paste system.