Filling subquarter-micron trench structure with high-purity copper using plasma reactor with H atom source

A plasma chemical vapor deposition reactor with an additional source of H atoms, in which concentrations of both H atoms and Cu-containing radicals are controllable independently, is developed to fill fine patterns for interconnects with high-purity Cu. Cu-filling property in trench structure with the reactor is evaluated under deposition conditions of high-purity (≈100%) Cu films. The surface reaction probability β of Cu-containing radicals is deduced from the coverage shape of Cu deposition in the trench structure and its Monte Carlo simulation. With decreasing the main discharge power P_m, the β value decreases from 0.2 for P_m = 35 W to 0.01 for P_m = 3 W. Using this reactor, we have realized filling of high purity Cu in a trench 0.3 μm wide and 0.9 μm deep.