This paper reviews the CMP for electroplated copper layers employing in copper interconnection layer. Adhesion strength is so low, for instance, 10 gf, in conventional copper layer on TaN barrier layer that peeling occurs easily both during annealing and CMP at low pressure. This is due to that highly stressed copper layer is formed on Ta/TaN barrier layer. To solve this serious problem, deposition and formation of low stress copper layers are strongly requested. Critical pressure occurring of the peeling, PC, increases with the reduction of stress in the seed layer, where the stress is reduced by the agglomeration of seed layer. Other requirement is to make polishing by charge transfer polishing employing MnO_2 slurry instead of mechanical polishing. Critical pressure, PC, increases from 3 to 9 psi with employing abrasive free MnO_2 slurry for same copper interconnection layer. This result shows clearly that problem of the peeling can be solved with the enhancement of adhesion strength by these methods. Contamination at the surface of low s interlayer in the copper CMP is also studied. Heavy and light contamination occurs with polishing by Al_2O_3 and MnO_2 slurry.
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