Method and apparatus for dispatching workpieces to tools based on processing and performance history

A system, comprising:

• a plurality of tools capable of performing a selected operation in a process flow;
• and
• a tool ranking unit operable to retrieve metrology data associated with a plurality of workpieces previously processed at the selected operation, determine a processing context associated with each of the workpieces, the processing context identifying a plurality of previous operations performed on the associated workpiece prior to the selected operation and a previous tool associated with each of the previous operations, determine a plurality of performance metrics for a plurality of tools capable of performing the selected operation based on the metrology data, each performance metric being associated with a particular tool and a particular processing context, identify a set of the performance metrics for the plurality of tools having a processing context matching a processing context of a selected workpiece awaiting performance of the selected operation, and generate a tool score for each of the tools based on the performance metrics;
• and
• a dispatching unit operable to dispatch the selected workpiece for processing in a selected one of the plurality of tools based on the tool scores.

A system for dispatching workpieces in a process flow including a plurality of operations, comprising:

• means for retrieving metrology data associated with a plurality of workpieces processed at a selected operation in the process flow;
• means for determining a processing context associated with each of the workpieces, the processing context identifying a plurality of previous operations performed on the associated workpiece prior to the selected operation and a previous tool associated with each of the previous operations;
• means for determining a plurality of performance metrics for a plurality of tools capable of performing the selected operation based on the metrology data, each performance metric being associated with a particular tool and a particular processing context;
• means for identifying a set of the performance metrics for the plurality of tools having a processing context matching a processing context of a selected workpiece awaiting performance of the selected operation;
• and
• means for dispatching the selected workpiece for processing in a selected one of the plurality of tools based on the set of performance metrics.