Patent ID: 7005081

Claim:
An ingot cutting method, wherein a crystalline ingot is positioned within an etching gas and the etching gas is excited by illumination of light from a light source onto said crystalline ingot, thereby making a component of the etching gas react chemically with a component of said crystalline ingot and volatilizing the component of said crystalline ingot to cut said crystalline ingot and obtain wafers, comprising the steps of: preparing said crystalline ingot; and guiding light from a light source to said crystalline ingot via a sheet-like, bar-like, or fiber-like optical wave guide, wherein during the cutting of said crystalline ingot, said optical wave guide and said crystalline ingot are moved relative to each other in a manner such that said optical wave guide becomes inserted into a slit formed in said crystalline ingot by volatilization of said crystalline ingot and the distance between the light exiting surface of said optical wave guide and the chemically reacting part at the cut part of said crystalline ingot is kept substantially fixed.