This paper describes the delamination in chemical mechanical polishing for copper interconnection layer. Adhesion strength for the electroplating copper layer (Cu/barrier layer) is determined mainly by barrier layer. Adhesion strength is considerably lower for conventional copper layer deposited on Ta/TaN and TAN barrier land decreases with annealing. Since the stress relaxation can occur during void formation and delamination, critical pressure for the delamination decreases to 120 g/cm(2). Critical pressure at the barrier layer/low e, however, is not affected by the barrier layer. It decreases practically from 350 to 200 g/cm(2) with reduction of dielectric constant from 3.3 to 2.7 in SiOC interlayer. Thus, better adhesion strength can be attained by increasing dielectric constant in this low e layer. Delamination occurs at lower polishing pressure at the barrier/PAE low epsilon interlayer. (C) 2004 Published by Elsevier B.V.