Ring-shaped element for etcher and method for etching substrate using the same

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.

What is claimed is: 
     
         1 . A ring-shaped element for an etcher, comprising:
 a body portion comprising an upper surface and a bottom surface spaced a distance from each other by an outer diameter surface connecting an outer contour line of the upper surface and an outer contour line of the bottom surface, and an inner diameter surface connected to an inner contour line of the upper surface; and   a mounting portion comprising an upper surface comprising an outer diameter directly connected to the inner diameter surface of the body portion at a position lower than the upper surface of the body portion, a bottom surface connected to the bottom surface of the body portion, and spaced a distance from the upper surface by an inner diameter surface connecting an inner contour line of the upper surface and an inner contour line of the bottom surface,   wherein the upper surface of the mounting portion is stepped from the upper surface of the body portion to constitute a substrate mounting portion thereon,   wherein the surface or entire body of the ring-shaped element comprises necked boron carbide-containing particles, and   wherein the thermal conductivity of the ring-shaped element at 400° C. is 27 W/m·K or less.   
     
     
         2 . The ring-shaped element according to  claim 1 , wherein a first distance between the upper surface of the body portion and the bottom surface of the body portion is 1.5 to 3 times a second distance between the upper surface of the mounting portion and the bottom surface of the mounting portion. 
     
     
         3 . The ring-shaped element according to  claim 1 , wherein the upper surface of the body portion or the upper surface of the mounting portion has a roughness Ra of 0.1 μm to 1.2 μm. 
     
     
         4 . The ring-shaped element according to  claim 1 , wherein the upper surface of the body portion or the upper surface of the mounting portion has a porosity of 3% or less. 
     
     
         5 . The ring-shaped element according to  claim 1 , wherein the upper surface of the body portion or the upper surface of the mounting portion comprises a ratio of thermal conductivity at 25° C. to that at 800° C. of 1:0.2 to 1:3. 
     
     
         6 . The ring-shaped element according to  claim 1 , wherein an area of pores having a diameter of 10 μm or more accounts for 5% or less of the area of all pores on the upper surface of the body portion or the upper surface of the mounting portion. 
     
     
         7 . The ring-shaped element according to  claim 1 , wherein the ring-shaped element does not form particles upon contact with fluorine or chlorine ions in a plasma etcher. 
     
     
         8 . The ring-shaped element according to  claim 1 , wherein the etch rate of the upper surface of the body portion is 55% or less of that of the upper surface of a body portion made of single-crystal silicon (Si). 
     
     
         9 . The ring-shaped element according to  claim 1 , wherein the replacement time of the ring-shaped element is at least twice that of a ring-shaped element made of single-crystal silicon when the replacement time is defined as the time required for the height of the body portion to fall 10% or more of its initial height. 
     
     
         10 . The ring-shaped element according to  claim 1 , wherein the ring-shaped element is a focus ring configured to mount a substrate in a chamber of a plasma processing system. 
     
     
         11 . An etcher comprising the ring-shaped element according to  claim 1  as a focus ring. 
     
     
         12 . A method for etching a substrate, comprising: mounting the ring-shaped element according to  claim 1  as a focus ring in a plasma etcher; arranging a substrate on the upper surface of the mounting portion; and operating the plasma etcher to etch the substrate in a predetermined pattern. 
     
     
         13 . A ring-shaped element for an etcher, comprising:
 a body portion comprising an upper surface connected to an outer diameter surface; and   a mounting portion disposed inward from the body portion comprising a mounting surface stepped down from the upper surface of the body portion at an inner diameter surface,   wherein the inner diameter surface is stepped inward by the mounting surface,   wherein the mounting surface is configured to support a substrate,   wherein a surface of the ring-shaped element comprises necked boron carbide-containing particles, and   wherein the thermal conductivity of the ring-shaped element at 400° C. is 27 W/m·K or less.   
     
     
         14 . The ring-shaped element according to  claim 13 , wherein the body of the ring-shaped element comprises necked boron carbide-containing particles.