Oxide removal from copper by using argon and fluorocarbon plasma treatment

Oxidized copper was treated with an inductively coupled argon plasma or pul sed glow discharge (PGD) fluorocarbon plasma. In both cases the Cu substrat e was biased to a negative voltage of 4 kV to promote sputtering and etchin g of the oxide layer. In the case of argon sputtering, spectrophotometer da ta were taken in situ to evaluate the oxide removal as a function of time. In addition, the amount of oxide was measured before and after the argon sp uttering and C2F6 etching using resonance Rutherford backscattering spectro metry (RBS). The spectrophotometer data showed saturation of the oxide remo val process after 2 h of argon sputtering. From the resonance RES measureme nts the oxide on the surface of copper was found to drop by 70% after 2 h o f argon plasma sputtering and 90% after 2 h of C2F6 plasma etching. (C) 200 1 Elsevier Science B.V. All rights reserved.