What is the flat edge (Flat) of a silicon wafer?
Flat can also be referred to as a locating edge.
Instead of a full circle, 2, 4, or 6 inch wafers have a missing corner cut off. After the ingot is drawn by the CZ method and before it is cut into wafers, once the crystal orientation is determined, one or more flat edges are cut into the ingot with a diamond saw.
Thus the wafer has 1-2 locating edges, the long one at the bottom of the wafer and the short one in a variable position, following the crystal orientation and doping type.
