Electromagnetic Casting Apparatus for Silicon
AssigneeConsarc Corporation
InventorKyojiro Kaneko
Life of this patent
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Abstract
This invention aims at providing a silicon electromagnetic casting apparatus for accurate and easy manufacturing of high quality silicon ingots. This apparatus uses a furnace vessel 100, a conductive crucible 200 installed in the internal part of the furnace vessel 100 and an induction coil 300 installed on the outer circumference of the crucible 200. Constant pressure is maintained in the internal part of the furnace vessel 100 using a prescribed gas and the silicon inside the above mentioned crucible 200 is solidified after melting it by induction heating by applying voltage on the induction coil 300. The induction coil 300 is made by placing 2 induction coils 310 and 320 having different induction frequencies one above the other.
Claims18
A silicon electromagnetic casting apparatus comprising a furnace vessel, a conductive crucible installed within the furnace vessel and an induction coil element installed around the outer circumference of the conductive crucible, wherein a constant pressure is maintained within the furnace vessel using a prescribed gas and a silicon in the conductive crucible is moved downwards along the center line of the furnace vessel, and melted by induction heating by applying a terminal voltage to the induction coil element to form a molten silicon, and thereafter the molten silicon is solidified;
- characterized in that the induction coil element comprises a plurality of induction coils of different induction frequencies arranged one above another in which the silicon in the crucible is melted by induction heating, wherein among the plurality of induction coils of different induction frequencies, the lowest-disposed induction coil is operating at a high induction frequency, with which the high induction frequency the stirring effect on the molten silicon is low and a static state of the molten silicon is maintained.
(canceled)
A silicon electromagnetic casting process comprising the steps of supplying a silicon into a conductive crucible disposed within a furnace vessel, the conductive crucible having a plurality of induction coils surrounding the outer circumference of the conductive crucible;
- circulating a coolant through a plurality of electrically insulated segments of the conductive crucible;
- supplying a prescribed gas to the interior of the furnace vessel to maintain a constant pressure within the furnace vessel;
- and applying a terminal voltage to the plurality of induction coils to melt the silicon by induction heating and form a molten silicon;
- characterized by the steps of supplying a different induction frequency to each of the plurality of induction coils;
- supplying a high induction frequency to the lowest-disposed one of the plurality of induction coils with the high induction frequency suppressing stirring of the molten silicon and maintaining a static state of the molten silicon;
- and solidifying the molten silicon.
A silicon ingot formed by an electromagnetic casting process comprising the steps of supplying a silicon into a conductive crucible disposed within a furnace vessel, the conductive crucible having a plurality of induction coils surrounding the outer circumference of the conductive crucible;
- circulating a coolant through a plurality of electrically insulated segments of the conductive crucible;
- supplying a prescribed gas to the interior of the furnace vessel to maintain a constant pressure within the furnace vessel;
- and applying a terminal voltage to the plurality of induction coils to melt the silicon by induction heating and form a molten silicon;
- characterized by the steps of supplying a different induction frequency to each of the plurality of induction coils;
- supplying a high induction frequency to the lowest-disposed one of the plurality of induction coils with the high induction frequency suppressing stirring of the molten silicon and maintaining a static state of the molten silicon;
- and
- forming the silicon ingot from solidification of the molten silicon within the conductive crucible.
Dependencies are inferred from the claim text.