Bottom-up fill of submicron features in catalyst-enhanced chemical vapor deposition of copper

Abstract

A formation process for copper bottom-up fillings of submicron via holes and trenches using iodine as a catalytic surfactant and hexafluoroacetylacetonate-copper-vinyltrimethylsilane $[(hfac)Cu^I(vtms)]$ in catalyst-enhanced chemical vapor deposition (CECVD) of copper is presented. During the copper deposition, the film growth rate of copper at the bottom of the features is continuously accelerated until the completion of the bottom-up filling, and this results in the bottom-up filling of the submicron features has been previously considered not viable in vacuum deposition techniques. The accelerated film growth appears to be due to the accumulation of the catalytic surfactant of iodine onto the surface of the copper films growing at the bottom of the submicron features that is considered as the result of the reduction of the side-wall area in the submicron features as the film grows. The newly developed technique for the copper bottom-up filling of submicron features will give a great impact on on-chip copper interconnects for the next generation of microelectronic devices. Moreover, the film growth mode in a bottom-up fashion on submicron features is expected to be universal to other systems of chemical vapor deposition, which use a catalytic surfactant.