Patent ID: 6188323
Filing Date: 2001-02-13
Classification: H01L

Abstract:
A system for mapping positional information of a plurality of workpieces seated in a container on a load port of a tool for processing the plurality of workpieces, the system comprising:wherein said load port including an access port through which the plurality of workpieces are transferred, and a port door capable of covering the access port and capable of moving in a vertical direction relative to the workpieces, away from the access port;a transmitter mounted on the port door and moving with the port door, said transmitter capable of transmitting a beam into the container;a receiver mounted on the port door and moving with the port door, said receiver capable of receiving said beam and said receiver capable of indicating a first state when said receiver receives said beam and said receiver capable of indicating a second state when said receiver does not receive said beam; andmeans for determining the positional information of the plurality of workpieces base on a switching of said receiver between said first and second states.