Patent ID: 7993489
Filing Date: 2011-08-09
Classification: C23F,H01J,H01L

Abstract:
1. A plasma processing apparatus comprising: a process container configured to accommodate a target substrate and to be vacuum-exhausted, said process container including a conductive casing that is grounded; a first electrode supported by the casing through an insulating member and serving as an upper electrode inside the process container; a second electrode disposed below the first electrode and opposite the first electrode inside the process container and serving as a lower electrode configured to support the target substrate; a first RF (radio frequency) power supply configured to apply a first RF power for plasma generation to the first electrode; a DC (direct current) power supply configured to apply a DC voltage for plasma generation to the first electrode; and a process gas supply unit configured to supply a process gas into the process container, plasma of the process gas being generated between the first electrode and the second electrode, wherein the first electrode includes a conductive electrode support, and an outer electrode plate and an inner electrode plate both supported at a lower side of the conductive electrode support facing the second electrode, such that the inner electrode plate spreads directly above the second electrode, the outer electrode plate surrounds the inner electrode plate and is decoupled for DC relative to the inner electrode plate, and the outer electrode plate has a planar outer contour larger than the second electrode, a gas diffusion cell is formed inside the electrode support and gas delivery holes are formed in the inner electrode plate, such that the process gas from the process gas supply unit is supplied through the gas diffusion cell and the gas delivery holes into a space between the first electrode and the second electrode, the electrode support is connected to the first RF power supply and the DC power supply, the outer electrode plate is physically connected to the electrode support with a dielectric film interposed therebetween such that the outer electrode plate is decoupled for DC and coupled for RF relative to the electrode support, the inner electrode plate is physically connected to the electrode support without the dielectric film interposed therebetween such that the inner electrode plate is coupled for DC and for RF relative to the electrode support, and an RF current from the first RF power supply substantially flows into the outer electrode plate and the inner electrode plate, while a DC current from the DC power supply substantially does not flow into the outer electrode plate but substantially flows into the inner electrode plate.