Patent ID: 8172945
Filing Date: 2012-05-08
Classification: C30B,Y10S,Y10T

Abstract:
1. A vitreous silica crucible for pulling a single-crystal silicon ingot, comprising a double layered structure constituted by an outer layer composed of high-purity amorphous vitreous silica with a bubble content of 1 to 10% and a purity of 99.99% or higher, and an inner layer composed of high-purity amorphous vitreous silica with a bubble content of 0.6% or less and a purity of 99.99% or higher, wherein, with regard to an inner surface of the high-purity vitreous silica crucible, at least for the inner surface between ingot-pulling start line and ingot-pulling end line of a silicon melt surface, (a) a longitudinal section of the inner wall surface is in the shape of the wave to be a multi ring-groove patterned face, and (b) depth of the ring grooves constituting the multi ring-groove patterned face is set in the range of 0.5 to 2 mm and width of the ring grooves constituting the multi ring-groove patterned face is set in the range of 10 to 100 mm, respectively, such that pinhole defects in the large-diameter single-crystal silicon ingot are reduced.