Ingot and methods for ingot grinding

Abstract

A method of grinding an ingot for use in manufacturing a semiconductor or solar wafer is disclosed. The method includes providing an ingot including four flat sides and four rounded corner portions, each corner portion extending between an adjacent pair of the flat sides, and grinding a plurality of planar facets on each corner portion, each planar facet of the corner portion joined to an adjacent facet at a juncture and oriented such that each corner portion has a substantially arcuate shape. A wafer and ingot are also disclosed.

What is claimed is: 
     
         1 . A method of grinding an ingot for use in manufacturing semiconductor or solar wafers, the method comprising:
 providing an ingot including four flat sides and four corner portions, each corner portion extending between an adjacent pair of the flat sides; and   grinding a plurality of planar facets on each corner portion, each planar facet of the corner portion joined to an adjacent facet at a juncture and oriented such that each corner portion has a substantially arcuate shape.   
     
     
         2 . A method in accordance with  claim 1 , wherein grinding a plurality of planar facets comprises:
 rotating the ingot to a predetermined position;   advancing a grinding surface towards the corner portion such that the grinding surface forms one of the planar facets on the corner portion; and   retracting the grinding surface from the corner portion.   
     
     
         3 . A method in accordance with  claim 1 , further comprising smoothing the junctures such that each corner portion has a smooth, creaseless surface. 
     
     
         4 . A method in accordance with  claim 3 , wherein smoothing the junctures comprises:
 rotating the ingot back and forth about a longitudinal axis of the ingot in small increments; and   applying a grinding surface to the junctures while the ingot is rotated back and forth.   
     
     
         5 . A method in accordance with  claim 1 , wherein each corner portion includes a first planar facet joined to a first flat side at a first interface and a second planar facet joined to a second flat side at a second interface, the method further comprising smoothing the first and second interfaces to form smooth surfaces between the corner portions and the flat sides. 
     
     
         6 . A method in accordance with  claim 1 , wherein providing an ingot comprises providing an ingot made of mono-crystalline silicon. 
     
     
         7 . A method in accordance with  claim 1 , wherein grinding a plurality of planar facets on each corner portion comprises grinding the plurality of planar facets such that each substantially arcuate corner portion has a radius of approximately 100 millimeters. 
     
     
         8 . A method in accordance with  claim 1 , wherein grinding a plurality of planar facets comprises grinding a plurality of planar facets on each corner portion such that each corner portion includes a finite number of planar facets and includes at least six planar facets. 
     
     
         9 . A method in accordance with  claim 1 , wherein grinding a plurality of planar facets comprises grinding a plurality of planar facets on each corner portion such that each facet of the plurality of planar facets has the same length. 
     
     
         10 . An ingot of semiconductor or solar material, the ingot comprising:
 four flat sides; and   a corner portion extending between each adjacent pair of the flat sides, each corner portion including a plurality of planar facets, each planar facet of the corner portion joined to an adjacent facet at a juncture and oriented such that each corner portion has a substantially arcuate shape.   
     
     
         11 . An ingot in accordance with  claim 10 , wherein each juncture is rounded such that each corner portion has a smooth, creaseless surface. 
     
     
         12 . An ingot in accordance with  claim 10 , wherein each corner portion includes a first planar facet joined to a first flat side at a first interface and a second planar facet joined to a second flat side at a second interface, and wherein the first and second interfaces are rounded to form smooth surfaces between the corner portions and the flat sides. 
     
     
         13 . An ingot in accordance with  claim 10 , wherein the ingot is made of mono-crystalline silicon. 
     
     
         14 . An ingot in accordance with  claim 10 , wherein each substantially arcuate corner portion has a radius of approximately 100 millimeters. 
     
     
         15 . An ingot in accordance with  claim 10 , wherein each corner portion includes at least six planar facets. 
     
     
         16 . An ingot in accordance with  claim 10 , wherein each of the plurality of planar facets has the same length. 
     
     
         17 . An ingot in accordance with  claim 10 , wherein each corner portion includes only six planar facets. 
     
     
         18 . An ingot in accordance with  claim 10 , wherein the plurality of facets are formed by grinding the ingot with at least one cup wheel. 
     
     
         19 . An ingot in accordance with  claim 18 , wherein the plurality of facets are formed by grinding the ingot using both a first cup wheel with a rough grinding surface and a second cup wheel with a fine grinding surface. 
     
     
         20 . An ingot in accordance with  claim 10 , wherein each corner portion includes a finite number of planar facets and includes at least six planar facets.