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Complete-abrasive-free process for copper (Cu) damascene interconnection has been developed. The process is a combination of a newly developed abrasivefree chemical polishing (AFP) of Cu and dry etching of a barrier metal layer.Complete stop-on-barrier characteristics of Cu polishing are attained by using the new polishing agent and a polyurethane polishing pad. This combination produces a very clean, scratch-free, anticorrosive polished surface, and the total depth of erosion and dishing is reduced to less than one fifth of that produced by conventional slurries even after 100% over polishing. And it is shown that the developed AFP significantly reduces both Cu line resistance and its deviation. IntroductionChemical mechanical polishing (CMP) of Cu is one of the most important techniques for fabricating Cu damascene interconnects. Since conventional CMP slurries contain alumina abrasives, which are mechanically very hard, many scratches are generated not only on Cu but also on a Si02 film surface. The Si02 surface damage produced at the end of barrier metal CMP degrades breakdown reliability. Si02 erosion and Cu dishing were also serious problems, especially in the area of high pattern density [ 13. This erosion and dishing degrades the interconnects planarity and makes it difficult to fabricate high-density multilevel interconnects at a high yield. In order to minimize the erosion, slurryless polishing, which is a combination of an abrasive contained pad (whet stone) and

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