Semiconductor wafer carrier mapping sensor
AssigneeCyberOptics Semiconductor, Inc.
InventorFelix J. Schuda
Life of this patent
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Abstract
An improved laser-based wafer carrier mapping sensor is provided. The sensor includes a number of improvements including laser source improvements; optical improvements; and detector improvements. Laser source improvements include the type of laser sources used as well as the specification of size and power of such sources. Optical improvements include features that intentionally defocus the laser stripe on the wafer as well as additional features that help ensure precision stripe generation. Detector improvements include increasing gain while decreasing the effects of ambient light. Various combinations of these features provide additional synergies that facilitate the construction of a sensor with significantly improved dynamic response while decreasing the frequency of false cross slot errors.
Claims14
A wafer carrier mapping sensor comprising:
- at least one laser source adapted to generate a diverging laser beam;
- a focusing lens disposed to receive the diverging laser beam and focus the beam near a wafer edge;
- a cylinder lens disposed to receive the beam and diverge the beam in a first direction, generating a stripe;
- a detector adapted to receive laser light reflected from the wafer edge to produce a sensor output signal;
- and
- wherein the focal point is spaced from the wafer edge to reduce skirt illumination.
A wafer carrier mapping sensor comprising:
- a detector adapted to sense a laser stripe on a wafer edge to provide a signal indicative thereof;
- a laser stripe generator for generating a laser stripe having a width in a first direction greater than a height in a second direction, a center and a peak intensity at the center;
- and
- wherein the stripe includes a region spaced from the center 1 mm in the second direction, and wherein an intensity at the region is less than or equal to about 1/10000 of the peak intensity.
Dependencies are inferred from the claim text.