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US 5,567,300 AGranted
Electrochemical metal removal technique for planarization of surfaces
AssigneeIBM Corporation
InventorsMadhav Datta, Terrence R. O'Toole
Life of this patent
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Abstract
A high speed electrochemical metal removal technique provides for planarization of multilayer copper interconnection in thin film modules. The process uses a neutral salt solution, is compatible with the plating process and has minimum safety and waste disposal problems. The process offers tremendous cost advantages over previously employed micromilling techniques for planarization.
Claims22
An electrochemical cell for electrochemical planarization of a first electrode surface, comprising:
- a second electrode surface generally parallel to the first electrode surface;
- scanning means for relative lateral motion of the second electrode surface parallel to the first electrode surface;
- means for providing an aqueous electrolyte;
- additive substance means for providing an electrical resistance additive substance;
- impingement means for a) combining said aqueous electrolyte and said electrical resistance additive substance to form a resistive electrolytic salt mixture and b) disposing said resistive electrolytic salt mixture by localized impingement towards said first electrode surface and from said second electrode surface;
- and
- voltage means;
- wherein the first electrode surface is electrochemically planarized when a potential difference is applied across the cell by the voltage means.
5 more elements
An electrochemical cell for electrochemical planarization of a first electrode surface, comprising:
- a second electrode surface generally parallel to the first electrode surface;
- scanning means for relative lateral motion of the second electrode surface parallel to the first electrode surface;
- means for providing an aqueous electrolyte;
- additive substance means for providing an electrical resistance additive substance;
- means for a) combining said aqueous electrolyte and said electrical resistance additive substance to form a resistive electrolytic salt mixture and b) disposing said resistive electrolytic salt mixture between said first electrode surface and said second electrode surface;
- and
- voltage means;
- wherein the first electrode surface is electrochemically planarized when a potential difference is applied across the cell by the voltage means;
- and
- wherein the additive substance means provides the additive substance in the form of a resistive organic substance at a molarity greater than 1 M.
7 more elements
An electrochemical cell for electrochemical planarization of a first electrode surface, comprising:
- a second electrode surface generally parallel to the first electrode surface;
- scanning means for relative lateral motion of the second electrode surface parallel to the first electrode surface;
- means for providing an aqueous electrolyte;
- additive substance means for providing an electrical resistance additive substance;
- means for a) combining said aqueous electrolyte and said electrical resistance additive substance to form a resistive electrolytic salt mixture and b) disposing said resistive electrolytic salt mixture between said first electrode surface and said second electrode surface;
- and
- voltage means;
- wherein the first electrode surface is electrochemically planarized when a potential difference is applied across the cell by the voltage means;
- and wherein the first electrode surface is copper and the electrolyte is selected from the group consisting of NaNO.sub.3 at a molarity of 2 M to 4 M and NaCl at a molarity of 2 M to 4 M.
6 more elements
An electrochemical cell for electrochemical planarization of a first electrode surface, said electrochemical cell comprising:
- a second electrode surface generally parallel to the first electrode surface;
- scanning means for providing relative lateral motion of the second electrode surface parallel to the first electrode surface;
- means for providing an electrolyte having a viscosity less than 20 centipoises and an ohmic resistivity of more than 5.0 ohm-centimeter and for disposing said electrolyte between said second electrode surface and said first electrode surface;
- and
- voltage means;
- wherein the first electrode surface is electrochemically planarized when a potential difference is placed across the cell.
3 more elements
A method of planarizing metal fihn on a substrate surface, the method including the steps of:
- providing a cathode;
- providing an aqueous electrolyte disposed between the film and the cathode;
- adding an electrical resistance additive substance to the electrolyte;
- mixing the electrolyte and the additive substance to form a resistive electrolytic mixture;
- providing voltage means;
- spraying the resistive electrolytic mixture through localized impingement onto said metal film;
- and
- establishing a potential difference between the film and the cathode by the voltage means while performing relative lateral motion of the cathode parallel to the film so that the film is electrochemically planarized.
5 more elements
A method of planarizing metal film on a substrate surface, the method including the steps of:
- providing a cathode;
- providing an aqueous electrolyte disposed between the film and the cathode;
- adding an electrical resistance additive substance to the electrolyte;
- mixing the electrolyte and the additive substance to form a resistive electrolytic mixture;
- providing voltage means;
- spraying the resistive electrolytic mixture through localized impingement onto said metal film;
- and
- establishing a potential difference between the film and the cathode by the voltage means while performing relative lateral motion of the cathode parallel to the film so that the film is electrochemically planarized,
- wherein the additive substance is a resistive organic substance at a molarity greater than 1 M.
6 more elements
An electrochemical cell for electrochemical planarization of a first electrode surface, comprising:
- a second electrode surface generally parallel to the first electrode surface and spaced from the first electrode surface by less than or equal to 3 millimeters;
- scanning means for relative lateral motion of the second electrode surface parallel to the first electrode surface;
- an aqueous electrolyte adapted to be disposed between the second electrode surface and the first electrode surface;
- an electrical resistance additive substance mixed with the electrolyte to form a resistive electrolytic mixture;
- and
- voltage means;
- wherein the first electrode surface is electrochemically planarized when a potential difference is applied across the cell by the voltage means.
4 more elements
An electrochemical cell for electrochemical planarization of a planar first electrode surface, comprising:
- a linear second electrode surface generally parallel to the first electrode surface;
- scanning means for relative lateral motion of the second electrode surface parallel to the first electrode surface;
- an aqueous electrolyte adapted to be disposed between the second electrode surface and the first electrode surface;
- an electrical resistance additive substance mixed with the electrolyte to form a resistive electrolytic mixture;
- means for spraying the resistive electrolytic mixture onto said first electrode surface by localized impingement;
- and
- voltage means;
- wherein the first electrode surface is electrochemically planarized when a potential difference is applied across the cell by the voltage means.
5 more elements
Dependencies are inferred from the claim text.