Radio frequency identification system and method for tracking silicon wafers

DETAILED DESCRIPTION The invention meets the above needs and overcomes the deficiencies of the prior art by providing an improved system and method of tracking semiconductor wafers.
This is accomplished by a radio frequency identification system having an encapsulated multi-page tag mounted on a wafer carrier and an associated tag reader.
Advantageously, the present invention uses a custom interface protocol which is well-suited for communicating one or more selected pages of data, including identifying information, between the tag and the reader and between the reader and a host computer.
The reader transmits and receives messages via a plurality of antennas, each located near a wafer processing station.
The host computer also controls the reader to write information to update the information stored in a particular tag or to transfer information from one tag to another in the event that the wafers are unloaded from the carrier.
In addition, such system is economically feasible and commercially practical and such method can be carried out efficiently and economically.
Briefly described, a system embodying aspects of the present invention tracks semiconductor wafers through processing operations performed at a plurality of stations.
The system includes a tag mounted on a wafer carrier in which the wafers are loaded for transport between the stations.
The tag includes a memory which has a plurality of pages storing information relating to the wafers in the carrier.
The stored information includes information identifying the carrier.
The system also includes a reader for reading the stored information from the tag pages.
The reader and tag communicate by radio frequency signals via one of a plurality of antennas connected to the reader.
Each antenna is located proximate to one or more of the stations and has a transmission range which defines a reader position.
The reader and tag communicate when the carrier is at the respective reader position.
The system further includes a host computer for processing the stored information read by the reader to track the wafers