Method for etching a wafer edge using a potassium-based chemical oxidizer in the presence of hydrofluoric acid

A method for chemically etching an edge of a wafer comprising:

• depositing a polysilicon layer on the wafer including at least one major surface of the wafer and the edge of the wafer;
• covering opposed major surfaces of the wafer to thereby protect the major surfaces;
• and
• exposing the edge of the wafer to a potassium-based chemical oxidizer in the presence of hydrofluoric acid while the opposed major surfaces are covered to thereby etch the edge of the wafer so as to remove at least the polysilicon layer from the edge of the wafer without removing the polysilicon layer from the at least one major surface of the wafer.

A method for fabricating wafers comprising:

• dividing a crystal ingot into a plurality of wafers;
• grinding an edge of at least one wafer to have a shape;
• depositing a polysilicon layer on the wafer including at least one major surface of the wafer and the edge of the wafer following said grinding step;
• etching the edge of the wafer with a potassium permnanganate in the presence of hydrofluoric acid to thereby remove the polysilicon layer from the edge of the wafer without removing the polysilicon layer from the at least one major surface of the wafer, wherein the ratio of hydrofluoric acid to potassium permanganate is between 2:1 and 4:1;
• rinsing the wafer following etching;
• and
• thermally annealing the wafer following rinsing.