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US 6,143,073 AGranted
Methods and apparatus for minimizing white point defects in quartz glass crucibles
AssigneeHeraeus Shin-Etsu America, Inc.
InventorsMarc A. Christman, Robert O. Mosier
Life of this patent
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Abstract
Methods and apparatus for manufacturing silica crucibles 9 containing few, if any, white point defects. The white point defects are reduced by decreasing the amount of silica vapor condensing on electrodes 4,5,6 used in the manufacturing process. The silica vapor condensation is decreased by providing a flow of a protective or non-reactive gas or gas mixture through protective devices 11,12,13, over portions of the electrodes where the silica vapor would otherwise condense.
Claims19
A method for making at least one silica crucible, comprising:
- providing a crucible substrate;
- providing a plurality of electrodes having an arc or plasma discharge therebetween;
- melting silica particles by introducing them through the arc or plasma discharge toward the crucible substrate;
- protecting a portion of the electrodes proximate the crucible substrate from silica vapor condensation;
- and
- cooling the crucible to its final form.
3 more elements
An apparatus for making a silica crucible, comprising:
- a mold for supporting a crucible;
- a plurality of electrodes having an arc or plasma discharge therebetween;
- means for introducing silica particles through the arc or plasma discharge and into the crucible substrate;
- and
- means for protecting the electrodes proximate the crucible substrate from silica vapor condensation.
2 more elements
Dependencies are inferred from the claim text.