Compliant silicon wafer handling system

Abstract

A compliant wafer comb assembly for use in transferring semiconductor wafers between wafer cassettes, wafer carriers, or other wafer holding devices. The compliant wafer comb includes a plurality of slots in which wafer(s) can be held while being transported. The slots are parallel to each other and downward sloping from one end of the comb to the other. The sloped arrangement causes a single wafer at a time to become engaged with the comb when a batch of wafers is transferred from a cassette or wafer holding device to the comb, allowing the compliant features of the comb to compensate for the misalignment of each wafer individually. The comb is coupled to a static base structure by a set of independent column springs which permit motion of the comb slots in any direction necessary to compensate for a wafer's misalignment. This permits transfer of a misaligned wafer or wafers from a cassette or other carrier to the comb without damaging the wafer(s). The present invention is also directed to a wafer handling system which includes the compliant comb and sensor(s) for monitoring when a wafer is severely enough misaligned that transfer to the comb would damage the wafer. In such a situation, a feedback signal generated by the sensor to an attached controller is used to alter the position of a robotic arm or other mechanism used to align the comb with respect to the wafers, or to halt the motion of the robot.