Method for removing electroplated metal facets and reusing a barrier layer without chemical mechanical polishing

摘要

A method for avoiding using CMP for eliminating electroplated copper facets and reusing barrier layer in the back end of line (“BEOL”) manufacturing processes. Electropolishing is employed to remove the deposited surface metal, stopping at the barrier layer to form a smooth surface that may be utilized in subsequent steps. The method is suitable for the electropolishing of metal surfaces after formation of filled vias for through-silicon via processes employing metals such as copper, tungsten, aluminum, or alloys thereof. The remaining barrier layer may be reused to fabricate the redistribution layer.

主权项

1. A method for forming a filled blind via, the method comprising the steps of:
defining a blind via in a wafer; depositing an insulation layer over a wafer surface and in the blind via; forming a barrier layer comprising a first metal and a seed layer comprising a second metal over the insulation layer, the barrier layer and the seed layer extending into the blind via; forming a third metal layer over the barrier layer and the seed layer, filling the blind via; removing overburden metal facets disposed outside the blind via by electropolishing, the overburden metal facets comprising the second metal and the third metal, to expose the barrier layer disposed over the wafer surface and to define a smooth surface; forming a first redistribution layer over the exposed barrier layer; and patterning the barrier layer by removing portions of the barrier layer extending beyond the first redistribution layer.