Semiconductor alignment tool

DETAILED DESCRIPTION OF THE DRAWINGS The invention is a semiconductor alignment tool having a housing that has a number of registration pins for mating with a standard semiconductor cassette.
A plurality of x-y axis sensors are embedded in a first surface of the housing.
The x-y axis sensors sense an edge of a semiconductor wafer as it is placed in the standard semiconductor cassette.
The sensor outputs are processed either at the tool or by software running on a computer.
The software determines the direction the wafer needs to move in order to be correctly located.
Once the semiconductor wafer is correctly located, the position information can be programmed into a robot.
The tool provides a low cost method of aligning robots to semiconductor cassettes.
The tool saves time and is more accurate than prior art methods.
FIG.
1 is a top, left perspective view of a tool 20 for aligning a robot arm to a cassette for holding semiconductor wafers in accordance with one embodiment of the invention.
The tool 20 has a housing 22 that is similar to a semiconductor cassette.
The housing 22 is made of metal in one embodiment and holds the required electronics.
The housing 22 has a slot one position 24 and a slot twenty-five position 26.
Once the robot has been calibrated to the slot one position 24 most robot models can then determine the other positions.
Semiconductor cassettes have a standard spacing between slots, so the robot just needs to increment the z-axis to place a wafer in slot two or slot ten.
Some robot models need to be calibrated to slot twenty-five in addition to slot one.
The tool 20 includes a z-axis non-intrusive detector.
The z-axis non-intrusive detector by SUNX model EX13B is suitable for this application.
The z-axis non-intrusive detector, in one embodiment, has an optical transmitter and an optical detector aligned on the slot one position 24.
When the semiconductor wafer is in the correct slot one position it breaks (reflects) the optical transmitter beam.
This is detected by the optical detector