Time-resolved optical emission spectroscopy is used to investigate the discharge of the RF pulse sputtering of copper. The time integrated emission of a neutral copper atom in RF pulse sputtering was found to be superior to emission in continuous mode. The increase stemmed from the concentration of the power in the sharp pulse at the breakdown of the discharge. The integrated emission reached its maximum at 50% duty ratio. A sudden drop in the copper emission in continuous mode from that of a 98% duty ratio was correlated with an absence of the power peak of the pulse mode. (C) 2007 Elsevier B.V. All rights reserved.