Abstract: According to one embodiment, a plasma processing apparatus includes a processing container processing a substrate, a power supply supplying an electric power into the processing container to generate plasma, an upper electrode arranged inside the processing container, a substrate mounting table including a lower electrode opposed to the upper electrode, and placing the substrate thereon, an edge ring arranged at an outer peripheral portion of the substrate mounting table to surround an periphery of the substrate, and a drive mechanism driving at least part of the edge ring up and down. The edge ring includes a lower ring mounted on the outer peripheral portion of the substrate mounting table, an upper ring mounted on the lower ring to be movable up and down by the drive mechanism, and an auxiliary ring arranged at a lower surface of the upper ring to be movable up and down together with the upper ring, and including a surface facing a side to be opened to an inside of the processing container.

Abstract: A composite material for enhancing traction between a surface of an article made of the material and a second contact surface is disclosed. Fine chips are encapsulated in covering material to form covered particles. The covered particles are evenly dispersed within a base material. The covering material is harder than the base material; the second contact surface material is harder than the covering material; and the fine chips are made from a material that is harder than the second contact surface material. As the surface of the article made of the material and the second contact surface interact, the fine chips are continuously exposed to the second contact surface. As a result, the fine chips are free to engage small indentations in the second contact surface and to bite into ice on the second contact surface, if any ice is present.