Patent ID: 6175777
Filing Date: 2001-01-16
Classification: H01L

Abstract:
A method for transferring a wafer cassette between an Automated Guide Vehicle (AGV) and process equipment in a semiconductor fabrication facility, the method comprising the steps of:when the AGV arrives at the process equipment, transmitting a first signal, indicative of a cassette transfer request, from the AGV to the process equipment;before the wafer cassette is transferred between the AGV and the process equipment, checking whether the process equipment is in a transfer mode, the process equipment when in said transfer mode being in a physical state ready and suitable for the transfer of the wafer cassette between the AGV and the process equipment;setting the process equipment to said transfer mode after the checking step if the process equipment was not already in said transfer mode;as long as the checking reveals that the process equipment is not yet in said transfer mode, postponing the transfer of a wafer cassette between the AGV and the process equipment and continuing to check whether the process equipment is in said transfer mode;transmitting a second signal representative of a cassette transfer authorization once the process equipment is in said transfer mode; andtransferring the cassette between the AGV and the process equipment once said first and second signals have been transmitted so as to avoid a mis-handling of the wafer cassette during the transferring of the cassette.