Patent ID: 6777314
Filing Date: 2004-08-17
Classification: H01L,H05K

Abstract:
A method of forming an electrical contact on a surface of a substrate, the method comprising the steps of:forming a first layer copper on the surface of the substrate, where the first layer is formed in substantially contiguous sheet across the surface of the substrate using an electroless plating process, applying a masking layer of photoresist to the first layer, where the masking layer leaves exposed first portions of the first layer and covers second portions of the first layer, immersing the substrate in a first electrolytic plating bath, applying a first electrical potential between the layer and the first electrolytic plating bath, thereby causing the formation of a second layer of nickel on the exposed first portions of the first layer, immersing the substrate in a second electrolytic plating bath, applying a second electrical potential between the first layer and the second electrolytic plating bath, thereby causing formation of a third layer of gold on the second layer, removing the masking layer from the substrate to expose the second portions of the first layer, and removing the exposed second portions of the first layer to form discrete contact pads from the first portions of the first layer and the overlying second layer and third layer.