Recovery method for platinum plating bath
AssigneeMicron Technology, Inc.
InventorDinesh Chopra
Life of this patent
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Abstract
A recovery system for platinum electrolytic baths operating at low current densities is disclosed. An oxidizing system is provided in a closed-loop recirculation system for platinum plating at low current densities. The oxidizing system reoxidizes Pt+2 ions, which are typically formed at low current densities, to Pt+4 ions by using oxidizers, for example peroxide. A sensor may be also provided to detect the relative concentration of [Pt+2] ions to [Pt+4] ions and to tailor the relative concentrations to a predetermined level.
Claims68
A method of electroplating a surface of a semiconductor wafer, comprising the steps of:
- placing said surface of said semiconductor wafer in a platinum electrolytic solution;
- using an electrode within said platinum electrolytic solution to electroplate said surface of said semiconductor wafer, said electroplating producing Pt+2 ions in said platinum electrolytic solution;
- removing at least a part of said platinum electrolytic solution having a first concentration of Pt+2 ions to an oxidizing area;
- reducing said first concentration of Pt+2 ions of said removed at least part of said electrolytic solution to a second lower concentration of Pt+2 ions;
- and
- returning said removed at least part of said electrolytic solution having said second lower concentration of Pt+2 ions to said electrolytic solution.
A method of operating an electroplating system, said method comprising the steps of:
- placing a semiconductor product in a platinum electrolytic solution of said electroplating system;
- electroplating platinum onto said semiconductor product, said electroplating generating Pt+2 ions in said platinum electrolytic solution;
- removing at least a part of said platinum electrolytic solution having a first concentration of Pt+2 ions to an oxidizing area;
- determining said first concentration of Pt+2 ions of said removed at least part of said platinum electrolytic solution in said oxidizing area;
- converting Pt+2 ions to Pt+4 ions in said removed at least part of said electrolytic solution;
- and
- returning said removed at least part of said platinum electrolytic solution having converted Pt+2 ions to Pt+4 ions to said electrolytic solution.
A method of reducing the concentration of Pt+2 ions present in a platinum electroplating solution, said method comprising the steps of:
- removing at least a part of said platinum electroplating solution having a first concentration of Pt+2 ions to an oxidizing area;
- oxidizing at least part of said Pt+2 ions in said oxidizing area to decrease said first concentration of Pt+2 ions;
- and
- returning said removed at least part of said platinum electroplating solution having a decreased concentration of Pt+2 ions to said platinum electroplating solution.
A method of forming a platinum electrode of an MIM capacitor, said method comprising the steps of:
- placing said MIM capacitor in a platinum electrolytic solution;
- electroplating platinum onto said MIM capacitor, said electroplating generating Pt+2 ions in said platinum electrolytic solution;
- removing at least a part of said platinum electrolytic solution having a first concentration of Pt+2 ions to an oxidizing area;
- determining said first concentration of Pt+2 ions of said removed at least part of said platinum electrolytic solution in said oxidizing area;
- converting Pt+2 ions to Pt+4 ions in said removed at least part of said electrolytic solution;
- and
- returning said removed at least part of said platinum electrolytic solution having converted Pt+2 ions to Pt+4 ions to said electrolytic solution.
Dependencies are inferred from the claim text.