Vitreous silica crucible and method of manufacturing the same

1. A method of manufacturing a vitreous silica crucible for pulling a silicon single crystal, comprising:

a silica powder layer forming process of forming the silica powder layer by depositing silica powder on an inner surface of a mold defining an outer shape of the vitreous silica crucible;

an arc heating process of fusing, by arc heating, the silica powder layer in the mold to form the vitreous silica crucible having a vitreous silica layer and terminating the arc heating so as to leave unfused silica powder layer between the vitreous silica layer and the mold;

a taking-out process of taking out the vitreous silica crucible from the mold;

a honing process of removing the unfused silica powder layer on the outer surface of the vitreous silica crucible; and

further comprising, after the taking-out process and before the honing process, a marking process of marking by a laser beam an identifier comprised of multiple groove lines constituting alphabetic characters, numeric characters, or a bar code on the outer surface of the vitreous silica crucible to identify various kinds of crucibles, wherein

each groove line after the honing process has a depth of 0.2 to 0.5 mm, and a width of 0.8 mm or more at the opening of the groove line, and each groove line has a cross-sectional shape of an inverse trapezoid;

each groove line is formed by:

(i) setting, on the outer surface of the vitreous silica crucible under the unfused silica powder layer, a focal point of the laser released from a laser marker;

(ii) in that state, reciprocally moving the focal point along a longitudinal direction of the groove line at a width-direction position to form a part of the groove line;

(iii) shifting the focal point in a width direction to a next width-direction position and repeating step (ii); and

(iv) repeating step (iii) to form each of the multiple groove lines with the inverse trapezoid cross section, wherein a width of an opening in the unfused silica powder layer is wider than a width of an opening in the each of the multiple groove lines, and the number of the width-direction positions is 3 to 10 for the each groove line.

2. The method of claim 1 , wherein the width at the opening of the groove line was 2 mm or less.

3. The method of claim 1 , wherein the laser is a carbon dioxide laser.

4. The method of claim 1 , wherein the laser is scanned 3 to 7 times at each of the width-direction positions.

5. The method of claim 1 , wherein the width of the groove line at the bottom is 30 to 95% of the width at the opening of the groove line.

6. The method of claim 1 , further comprising:

an inspection process of inspecting the vitreous silica crucible after the honing process,

a grinding process of, when a foreign substance is detected in the inspection process, removing the foreign substance by grinding, and

a re-arc heating process of re-arc heating the vitreous silica crucible after the grinding.

7. The method of claim 1 , further comprising a rim cutting process of removing an opening edge of the vitreous silica crucible in a certain width after the honing process, wherein

the identifier is marked on a position within 30 mm toward the bottom direction from the opening edge, after the rim cutting process, of the vitreous silica crucible.