Stacked solid via formation in integrated circuit systems

Abstract

A method of forming solid copper vias in a dielectric layer permits stacked up vias in a multi-layer multi-chip carrier. An conducting layer is deposited over a substrate and lines of a first interconnect layer formed on the substrate. An aperture formed in a photoresist layer over said lines is filled with copper by electroplating to form a solid via. The via can be polished until its top is flat. Using a photoresist mask, the conductive layer used for electroplating is removed between the lines. A dielectric layer is then formed over the lines and via. A bulge in the dielectric over the via is removed by etching through an aperture defined in a photoresist layer, which is then stripped. A second interconnect layer can be formed on the resulting structure. The foregoing steps can be iterated to build a multi-layer structure with stacked up vias.