SYSTEM AND METHOD OF GROWING SILICON INGOTS FROM SEEDS IN A CRUCIBLE AND MANUFACTURE OF SEEDS USED THEREIN
Systems and methods that reduce the overall cost of producing a silicon ingot are provided herein. More specifically, one or more surface pieces may be sliced from a silicon boule in relation to a plurality of nodes at a particular orientation. These one or more surface pieces may then be formed into one or more seeds having a specific length, width and thickness usable in a silicon ingot growth process. By utilizing these pieces to form one or more seeds, pieces of a boule which would have been previously discarded may now be used to form high quality seeds for use in a silicon ingot grow process.
1 . A method for manufacturing a seed for use in a silicon ingot growth process, the method comprising:
slicing, by a first cutting device, one or more surface pieces from a silicon boule in relation to a plurality of nodes at a particular orientation; and
forming the one or more surface pieces into one or more seeds having a specific length, width and thickness usable in a silicon ingot growth process.
2 . The method of claim 1 , further comprising:
cropping one or more of the surface pieces along predetermined cut lines prior to forming the one or more seeds.
3 . The method of claim 1 , wherein the one or more surface pieces are residual pieces formed as a result of squaring the silicon boule in relation to the plurality of nodes at a particular orientation to form a silicon brick.
4 . The method of claim 3 , wherein four residual pieces are formed as a result of squaring the silicon boule and wherein the brick has a pseudo square cross-sectional shape with a <100> orientation on each side surface.
5 . The method of claim 1 , wherein one or more surface pieces are cut, by a second cutting device, to form a first surface and a second surface of the surface piece, and as a result the cut surface piece has five flat surfaces and one curved surface.
6 . The method of claim 1 , wherein one or more surface pieces are cropped lengthwise to form two flat vertical side surfaces.
7 . The method of claim 6 , wherein one or more surface pieces are further cropped to form a flat horizontal top surface.
8 . The method of claim 5 , wherein the second cutting device cuts a first surface, a second surface, and a third surface of the surface piece, and as a result the cut surface piece has six flat surfaces.
9 - 14 . (canceled)
15 . The method of claim 1 , wherein:
the silicon boule has an axis of growth in a <100> direction.
16 . The method of claim 1 , wherein:
a vector drawn normal from the axis of growth through any node is a <110> direction.
17 . The method of claim 1 , wherein the seeds are formed having a diamond shape.
18 . The method of claim 17 , wherein the one or more surface pieces are cropped into a plank, and wherein a first cut is made by a second cutting device in the plank at about a 45 degree angle relative to an axis associated with the length the plank, and wherein a second cut is made by the cutting device at about a 45 degree angle relative to the axis associated with the length of the plank parallel with the first cut and at a predetermined length away from the first cut, wherein the first cut and the second cut form the diamond shaped seed.
19 . The method of claim 18 , wherein a first group of diamond shaped seeds have at least one side surface with a <110> orientation and at least one side surface with a <100> orientation.
20 . The method of claim 19 , wherein a second group of diamond shaped seeds have orientations that minor the first group.
21 - 23 . (canceled)
24 . A method for growing a silicon ingot utilizing at least one seed manufactured by claim 1 , the method comprising:
providing a crystal growth apparatus configured to promote ingot growth by directional solidification;
placing a plurality of seeds and a feedstock material in a crucible in the crystal growth apparatus;
heating and melting the feedstock material contained in the crucible, without substantially melting the seeds; and
removing heat from the crucible to form the silicon ingot.
25 . The method of claim 24 , wherein a first and second group of diamond shaped seeds are placed in the crucible to have a side surface with a <100> orientation in the first group in contact with a side surface with a <110> orientation in the second group.
26 . The method of claim 24 , wherein the plurality of seeds are stacked on top of each other in the crucible.
27 . The method of claim 24 , wherein the plurality of seeds have curved surfaces and are placed in the crucible in an alternating pattern of curved and flat surfaces.
28 . The method of claim 27 , further comprising fusing one or more gaps between neighboring seeds with liquid silicon to maintain a <100> crystal silicon orientation.
29 . (canceled)
30 . A system for manufacturing a seed for use in a silicon ingot growth process, the system comprising:
a first cutting device configured to slice one or more surface pieces from a silicon boule in relation to a plurality of nodes at a particular orientation; and
a second cutting device configured to form the one or more surface pieces into one or more seeds having a specific length, width and thickness usable in a silicon ingot growth process.
31 - 58 . (canceled)