Abstract: A manufacturing method of a ring-shaped element for an etcher, comprises a granulation operation comprising i) a slurry manufacturing process of preparing a slurry by mixing a raw material including boron carbide, a sinterability enhancer with a solvent; and ii) a granulation process of drying the slurry to prepare granulated raw material; a molding operation of manufacturing a green body by molding the granulated raw material; a sintering operation of carbonizing and sintering the green body to manufacture a sintered body; a shape operation of shaping the sintered body to a ring-shaped element for an etcher. The sinterability enhancer comprises one selected from the group consisting of carbon, boron oxide and combinations thereof.

Abstract: A boron carbide sintered body includes necked boron carbide-containing particles. The thermal conductivity of the boron carbide sintered body at 400° C. is 27 W/m·K or less and the ratio of the thermal conductivity of the boron carbide sintered body at 25° C. to that of the boron carbide sintered body at 800° C. is 1:0.2 to 1:3.

Abstract: A ring-shaped element for an etcher includes a body portion having an outer diameter surface connecting an outer contour of an upper surface and an outer contour of a bottom surface, and an inner diameter surface connected to an inner contour of the upper surface, and a mounting portion having an upper surface connected to the inner diameter surface of the body portion at a position lower than the upper surface of the body portion, and an inner diameter surface connecting an inner contour of the upper surface and an inner contour of a bottom surface. The upper surface of the mounting portion is stepped from the upper surface of the body portion to constitute a substrate mounting portion. The surface or entire body of the ring-shaped element includes necked boron carbide-containing particles, and the thermal conductivity of the ring-shaped element at 400° C. is 27 W/m·K or less.

Abstract: An arrangement of a word line driver stage for semiconductor memory device is disclosed. The present invention is characterized in that a word line driver stages are into several sub-stages WD11-WD51 within a memory cell array, and each word line extending from a first one or a second one of the sub-stages is alternatively coupled to the sub-stage adjacent thereto. Thus this arrangement is capable of reducing the signal transmission delay and eliminating the adverse factor in the current critical design rule and layout.