Selective Deposition of Thin Copper Films onto Siliconwith Improved Adhesion

A novel copper deposition method has been developed to plate silicon surfaces. Continuous copper films are obtained galvanically on p- or n-type, single- or polycrystalline silicon. The films possess homogeneous structure, smooth surface, and improved adhesion to the substrate. The plating bath comprises an aqueous solution containing a copper compound, ascorbic acid, ammonium fluoride, and an antistress agent. With this process, the use of seed layers to improve adhesion between metal and semiconductor is avoided.