| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method for producing a silica glass crucible in which deformation and strain at a high temperature in such a state that the crucible is filled with a raw material melt is suppressed and occurrence of brown mold is also suppressed, and which does not cause impurity contamination resulting from the crucible and is suitably used for pulling a semiconductor single crystal such as silicon in a good yield. <P>SOLUTION: The method for producing a silica glass crucible, in which the outer layer in the thickness direction is formed of natural silica glass and the inner layer is formed of synthetic glass, comprises forming the outer layer and the inner layer by vitrifying the natural silica raw material powder and the synthetic silica raw material powder by a reduced pressure arc fusing, wherein the total thickness of the outer layer and the inner layer in at least a straight body part is 6-16 mm, the thickness of the inner layer is 5-40% of the total thickness, each concentration of Na, K, Li, Ca, Al, Ti, Fe and Cu in the inner layer is≤0.1 ppm, the Na concentration in the outer layer is≤0.2 ppm, and the number of pores each having a diameter of≥20μm is≤20 pores/mm<SP>2</SP>at an area of a depth of≤0.5 mm from the inner surface of the crucible. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
