Silica glass crucible for pulling up silicon single crystal and method for manufacturing thereof
A silica glass crucible for pulling up a silicon single crystal including a wall part, a corner part and a bottom part is provided with an outer layer formed from an opaque silica glass layer which includes many bubbles, and an inner layer formed from a transparent silica glass layer which substantially does not include bubbles, wherein at least one part of an inner surface of the wall part and the corner part being an uneven surface formed with multiple damaged parts having a depth of 50 μm or more and 450 μm or less, and wherein a region among the inner surface of the bottom part within a certain range from the center of the bottom part being a smooth surface which does is substantially not formed with damage.
1. A silica glass crucible for pulling up a silicon single crystal including a wall part, a corner part and a bottom part, comprising:
an outer layer formed from an opaque silica glass layer which includes many bubbles; and
an inner layer formed from a transparent silica glass layer which substantially does not include bubbles, wherein
at least one part of an inner surface of the wall part and the corner part being an uneven surface formed with multiple damaged parts having a depth of 50 μm or more and 450 μm or less, and a region among the inner surface of the bottom part within a certain range from the center of the bottom part being a smooth surface which does is substantially not formed with damage.
2. The silica glass crucible as claimed in claim 1 , wherein the region within a certain range from the center of the bottom part includes a projection plane of the silicon single crystal.
3. The silica glass crucible as claimed in claim 1 , wherein the region within a certain range from the center of the bottom part includes a region within 50% of the diameter of the crucible from the center of the crucible bottom part.
4. The silica glass crucible as claimed in claim 1 , wherein the number of damaged parts formed on the inner surface of the corner part is more than the number of damaged parts formed on an inner surface of the wall part.
5. The silica glass crucible as claimed in claim 1 , wherein the vicinity of the top end of the wall part which does not contact with a silicon melt is a smooth surface not formed with damaged parts.
6. The silica glass crucible as claimed in claim 1 , wherein the shape of the damaged parts is a dimple shape.
7. The silica glass crucible as claimed in claim 1 , wherein the shape of the damaged parts is a long thin line shape.
8. The silica glass crucible as claimed in claim 1 , wherein the number of damaged parts is equal to 100 or more and 500 or less.
9. A silica glass crucible for pulling up a silicon single crystal including a wall part, a corner part and a bottom part, comprising:
an outer layer formed from an opaque silica glass layer which includes many bubbles; and
an inner layer formed from a transparent silica glass layer which substantially does not include bubbles, wherein
at least one part of an inner surface of the wall part and the corner part is rougher than an inner surface of the bottom part.
10. The silica glass crucible as claimed in claim 9 , wherein the inner surface of the corner part is rougher than the inner surface of the wall part.
11. A method for manufacturing a silica glass crucible, comprising:
forming a silica glass crucible by melting and vitrifying a silica powder; and
forming damaged parts having a depth of 50 μm or more and 450 μm or less on at least one part of an inner surface of a wall part and a corner part of the silica glass crucible.
12. The method for manufacturing a silica glass crucible as claimed in claim 11 , wherein the damaged parts are formed using a diamond pen.