Claims
- 1. A method of plating an article, comprising the steps of:providing an anode in proximity to said article; providing a cathode in contact with said article, wherein an electrostatic field is formed between said anode and said cathode in response to a voltage difference applied across said anode and cathode; providing an electrically conductive element proximate to said article; and applying a control voltage to said electrically conductive element to alter saidt electrostatic field proximate said article to control the plating of said article.
- 2. The method of claim 1, wherein said article comprises a wafer.
- 3. The method of claim 2, wherein said control voltage is selected to change a plating rate at a desired region of said wafer.
- 4. The method of claim 3, wherein said electrically conductive element comprises a ring that is generally coincident with a perimeter of said wafer during plating of said wafer.
- 5. The method of claim 4, wherein said control voltage is selected to reduce the plating rate near the perimeter of said wafer in order to compensate for an otherwise higher plating rate near said perimeter caused by a high resistance characteristic of a seed layer disposed on said surface of said wafer.
- 6. In a plating apparatus comprising a container, a cathode electrode, an anode electrode situated at a higher position within said container, and an intermediate electrode situated at an intermediate position within said container below said higher position, a method of plating an article situated at a lower position within said container below said intermediate position and having a metal seed layer in electrical contact with said cathode electrode, comprising:introducing plating fluid into said container to form a plating fluid bath; applying a positive voltage potential from said anode electrode to said cathode electrode to form an electrostatic field extending from said anode electrode to said article which causes plating deposition to occur over said metal seed layer; and applying a negative voltage potential from said intermediate electrode to said cathode electrode to alter said electrostatic field that extends from said anode electrode to said article to reduce a plating rate of said plating deposition at a desired region above said metal seed layer.
- 7. The method of claim 6, wherein said article comprises a wafer.
- 8. The method of claim 6, wherein said metal seed layer comprises copper.
- 9. The method of claim 6, wherein said intermediate electrode is configured into an annular ring generally coincident with a perimeter of said article.
- 10. The method of claim 6, wherein said negative voltage potential is selected to improve the uniformity of a plating deposition across said metal seed layer.
- 11. The method of claim 6, wherein said cathode electrode is situated within said container.
- 12. In a plating apparatus comprising a container, a cathode electrode, an anode electrode situated at a higher vertical position within said container, and an intermediate electrode situated at an intermediate vertical position within said container below said higher vertical position, a method of plating an article situated at a lower vertical position within said container below said intermediate vertical position and having a metal seed layer in electrical contact with said cathode electrode, comprising:introducing plating fluid into said container to form a plating fluid bath; forming a positive voltage potential from said anode electrode to said cathode electrode to form an electrostatic field that causes the plating, of said article; and forming a negative voltage potential from said intermediate electrode to said cathode electrode to alter the electrostatic field to control a plating rate of said article at a desired region.
- 13. The method of claim 12, wherein said article comprises a wafer.
- 14. The method of claim 12, wherein said metal seed layer comprises copper.
- 15. The method of claim 12, wherein said intermediate electrode is configured into an annular ring generally coincident with a perimeter of said article.
- 16. The method of claim 12, wherein said negative voltage potential is selected to improve the uniformity of a plating deposition across said metal seed layer.
- 17. The method of claim 12, wherein said cathode electrode is situated within said container.
CROSS-REFERENCES TO RELATED APPLICATIONS
This application is a Divisional Application of application Ser. No. 09/348,768, filed Jul. 7, 1999, now U.S. Pat. No. 6,197,182 which is incorporated herein by reference.
US Referenced Citations (9)