Vitreous silica crucible for pulling silicon single crystal and method of manufacturing the same

摘要

The present invention provides a vitreous silica crucible which can suppress the sidewall lowering of the crucible under high temperature during pulling a silicon single crystal, and a method of manufacturing such a vitreous silica crucible. The vitreous silica crucible 10 includes an opaque vitreous silica layer 11 provided on the outer surface side of the crucible and containing numerous bubbles, and a transparent vitreous silica layer 12 provided on the inner surface side. The opaque vitreous silica layer 11 includes a first opaque vitreous silica portion 11a provided on the crucible upper portion, and a second opaque vitreous silica portion 11b provided on the crucible lower portion. The specific gravity of the second opaque vitreous silica portion 11b is 1.7 to 2.1, and the specific gravity of the first opaque vitreous silica portion 11a is 1.4 to 1.8, and smaller than that of the second opaque vitreous silica portion. The particle size distribution of the material silica powder for the first opaque vitreous silica portion 11a is wider than that of the second opaque vitreous silica portion 11b, and the material silica powder for the first opaque vitreous silica portion 11a includes more fine powder than that for the second opaque vitreous silica portion 11b.

主权项

1. A vitreous silica crucible for pulling a silicon single crystal, the crucible having a sidewall portion, a curved portion, and a bottom portion, and having an opaque vitreous silica layer provided on an outer surface side of the crucible and containing numerous bubbles and a transparent vitreous silica layer provided on an inner surface side of the crucible, wherein
the opaque vitreous silica layer has a first opaque vitreous silica portion provided on a crucible upper portion belonging to a range from a crucible upper end to a first intermediate position below the upper end, and a second opaque vitreous silica portion provided on a crucible lower portion belonging to a range from the first intermediate position to a crucible lower end or a range from a second intermediate position below the first intermediate position to the crucible lower end, a height h1 of the first opaque vitreous silica portion is 0.1h0 to 0.6h0, where h0 is a height of the entire crucible, a specific gravity of the second opaque vitreous silica portion is 1.7 to 2.1, and a specific gravity of the first opaque vitreous silica portion is 1.4 to 1.8, and smaller than that of the second opaque vitreous silica portion, the OH group content of the opaque vitreous silica layer including both first and second opaque vitreous silica portions provided as the upper portion and lower portion, respectively, is less than 60 ppm, and at a position approximately 30 μm toward the outer surface side from a position where a bubble content rate of the transparent vitreous silica layer starts to increase, the bubble content rate reaches a bubble content rate of the opaque vitreous silica layer.