Conformal metal thin-film coatings in high-aspect-ratio trenches using a self-sputtered rf-driven plasma source

摘要

A thin-film coating system has been developed for the deposition of both conductive and insulating materials. The system employs a radio-frequency (rf)-discharge plasma source with four straight rf antennas, which is made of or covered with the deposition material, thus serving simultaneously as a sputtering target. The average deposition rate of the copper thin film can be as high as 500 nm/min when operated under continuous-wave mode. Film properties under different operating conditions (gas pressure and rf power) have been investigated experimentally. Three thin-film coating schemes have been developed, one of which has been demonstrated to be suitable for conformal deep-trench coating. Conformal coating over trenches of high-aspect ratio (>6:1) has been demonstrated at both micron and submicron scales.