METHOD AND APPARATUS FOR CALIBRATING SENSORS THAT DETECT WAFER PROTRUSION FROM A WAFER CASSETTE

摘要

A calibration gauge, an apparatus and a method for calibrating sensors that detect wafer protrusion from a wafer cassette using the calibration gauge. The calibration gauge includes a disk having a first region which is a circular sector of central angle A1 having a constant radius R1 about a center and an integral second region of increasing radius about the center, the increasing radius increasing from R1 to R2 through a central angle A2, wherein R2 is greater than R1 and A1+A2 equals 360°.

主权项

1. An apparatus, comprising:
a wafer cassette comprising a top, a bottom, opposite first and second ends and opposite sidewalls between said first and second ends, said cassette open at said top and said bottom, a plurality of slots formed in said sidewalls, each slot adapted to hold a circular wafer; a calibration gauge in the form of a disk having a first region which is a circular sector of central angle A1 having a constant radius R1 about a center and an integral second region of increasing radius about said center, the increasing radius increasing from R1 to R2 through a central angle A2, wherein R2 is greater than R1 and A1+A2 equals 360°; and wherein said disk is removeably positioned in a slot of said plurality slots and rotatable about said center, said second region of said disk extending past said opposite ends and said top of said wafer cassette.