Method of controlling chemical bath composition in a manufacturing environment
AssigneesInternational Business Machines Corporation, Novellus Systems, Inc.
InventorsJohn O. Dukovic, William E. Corbin, Jr., Erick G. Walton, Peter S. Locke, Panayotis C. Andricacos, James E. Fluegel, Evan Patton, Jonathan Reid
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Abstract
A method for controlling the composition of a chemical bath in which predictive dosing is used to account for changes in the composition of the bath in which the operating characteristics of the process are partitioned into a plurality of operating modes and the consumption or generation of materials related to the process are determined empirically and additions of material are made as appropriate.
Claims11
A method for controlling the concentration of a plurality of chemical species in a wet chemical bath of predetermined composition for a processing tool including a bulk tank, a plurality of workstations coupled to the bulk tank and a plurality of sources of additives, comprising the steps of:
- characterizing the status of the tool into said plurality of operational modes;
- determining a material balance for each of a plurality of chemical species under each operational mode,
- determining a minimum dose of additive for each said chemical species comprising the components of the bath;
- determining the rate at which each additive to the bath will be depleted or generated within each of said operational modes;
- determining when the value of each additive exceeds said minimum dose;
- and
- adding said minimum dose or greater of respective additives determined to have exceeded said minimum dose to said bath.
Dependencies are inferred from the claim text.