Abstract: Electroless deposition of Cu provides for repair of copper seed layers formed by vacuum deposition processes, for formation of copper seed layers on catalytic materials, and for bulk fill of damascene trenches and via openings. Electroless plating baths for such depositions are formulated for both room temperature and elevated temperature operation, and each include a copper source, an environmentally friendly reducing agent, a pH buffer, a complexing agent, and a surfactant.