Dependence of metal sheet resistance on metal etch/post-etch treatment andsubsequent process conditions

Metal sheet resistance (R-s) becomes more important in manufacturing sub-ha lf-micron devices, especially for logic devices. This study focuses on inve stigating the relationship of the metal R-s with metal etch/post-etch treat ment conditions and subsequent deposition and annealing conditions. Various experimental results related to the metal R-s variation with respect to co rrosion characteristics were described in detail. The metal R-2 was increas ed with chlorine flow rate due to more isotropic etching property of chlori ne plasma during the metal etch process. It was also found that the conditi ons of inter-metal dielectric (IMD) deposition and hydrogen annealing proce ss performed subsequently after the metal etch are dominant factors affecti ng the metal R-s. The metal R-s of the sample with H-2 annealing (400 degre esC, 30 min) increased up to 25.5% compared with the one obtained from the sample without H-2 treatment. The metal R-s was observed to be almost indep endent of the pitting corrosion induced by post-wet cleaning process. In ad dition, the change of the metal R-s for 48 h after metal etch and the mecha nism of the pitting corrosion deduced from AES analysis results are mention ed in this paper. (C) 2000 Published by Elsevier Science Ltd.