Methods of Forming Integrated Circuit Contact Pads Using Electroless Plating of Diffusion Barrier Layers

摘要

Methods of forming a contact pad include forming a copper pattern on a semiconductor substrate and forming a passivation layer on the copper pattern. The passivation layer is defined to have an opening therein that exposes at least a portion of an upper surface of the copper pattern. A diffusion barrier layer is formed in the opening by electroless plating the diffusion barrier layer onto the exposed portion of the upper surface of the copper pattern. This diffusion barrier layer operates as a barrier to copper out-diffusion from the copper pattern. These methods further include conformally depositing an underbump metallization layer onto at least a sidewall of the opening in the passivation layer and onto an upper surface of the diffusion barrier layer. A step is then performed to plate a contact bump (e.g., solder bump) onto a portion of the underbump metallization layer extending opposite the diffusion barrier layer.