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US 8,475,644 B2Granted
Method and apparatus for electroplating
AssigneeNovellus Systems, Inc.
InventorsSteven Mayer, Jingbin Feng, Zhian He, Jonathan Reid, Seshasayee Varadarajan
Life of this patent
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Abstract
An apparatus for electroplating a layer of metal onto the surface of a wafer includes an ionically resistive ionically permeable element located in close proximity of the wafer and an auxiliary cathode located between the anode and the ionically resistive ionically permeable element. The ionically resistive ionically permeable element serves to modulate ionic current at the wafer surface. The auxiliary cathode is configured to shape the current distribution from the anode. The provided configuration effectively redistributes ionic current in the plating system allowing plating of uniform metal layers and mitigating the terminal effect.
Claims20
An apparatus for electroplating metal onto a substrate, the apparatus comprising:
- (a) a plating chamber configured to contain an electrolyte and an anode while electroplating metal onto the substrate;
- (b) a substrate holder configured to hold the substrate such that a plating face of the substrate is positioned at a defined distance from the anode during electroplating, the substrate holder having one or more electrical power contacts positioned around a substantially circular perimeter and arranged to contact an edge of the substrate and provide electrical current to the substrate during electroplating;
- (c) an ionically resistive ionically permeable element shaped and positioned between the substrate and the anode during electroplating, the ionically resistive ionically permeable element having a substantially flat surface that is substantially parallel to and separated from a plating face of the substrate, wherein the ionically resistive ionically permeable element has an ionically resistive body with a plurality of perforations made in the body such that the perforations do not form communicating channels within the body and wherein said perforations allow for transport of ions through the element;
- (d) a variable field shaping element positioned between the ionically resistive ionically permeable element and the position of the anode for electroplating;
- and
- (e) a first auxiliary cathode located between the anode and the ionically resistive ionically permeable element, and peripherally oriented to shape the current distribution from the anode, while the first auxiliary cathode is supplied with current during electroplating;
- and
- (f) a second auxiliary cathode positioned to be located between the ionically resistive ionically permeable element and the substrate during electroplating, wherein the second auxiliary cathode is adapted to divert a portion of ionic current from an edge region of the substrate.
5 more elements
A method of plating a metal layer onto a substrate, the method comprising:
- (a) holding a substrate, having a working surface comprising conductive seed and/or barrier layer, in a substrate holder of an electroplating apparatus, wherein the apparatus comprises a plating chamber, an anode, and a variable field shaping element, a first auxiliary cathode and a second auxiliary cathode;
- (b) immersing the working surface of the substrate in an electrolyte solution and proximate an ionically resistive ionically permeable element positioned between the working surface and the anode contained in the plating chamber, the ionically resistive ionically permeable element having a flat surface that is parallel to and separated from the working surface of the substrate, wherein the variable field shaping element is positioned between the ionically resistive ionically permeable element and the position of the anode for electroplating;
- and wherein the ionically resistive ionically permeable element has an ionically resistive body with a plurality of perforations made in the body such that the perforations do not form communicating channels within the body and wherein said perforations allow for transport of ions through the element;
- (c) supplying current to the substrate with one or more electrical power contacts positioned around a substantially circular perimeter to plate the metal layer onto the seed and/or barrier layer;
- (d) supplying current to an auxiliary cathode located between the anode and the ionically resistive ionically permeable element, to thereby shape the current distribution from the anode;
- and
- (e) supplying current to the second auxiliary cathode located between the substrate and the ionically resistive ionically permeable element to divert a portion of ionic current from the edge portion of the substrate.
4 more elements
An apparatus for electroplating metal onto a substrate, the apparatus comprising:
- (a) a planting chamber configured to contain an electrolyte and a anode while electroplating metal onto the substrate;
- (b) a substrate holder configured to hold the substrate such that a plating face of the substrate is positioned at a defined distance from the anode during electroplating, the substrate holder having one or more electrical power contacts positioned around a substantially circular perimeter and arranged to contact an edge of the substrate and provide electrical current to the substrate during electroplating;
- (c) an ionically resistive ionically permeable element shaped and positioned between the substrate and the anode during electroplating, the ionically resistive ionically permeable element having a substantially flat upper surface that is substantially parallel to and separated from a plating face of the substrate, wherein the ionically resistive ionically permeable element has an ionically resistive body with a plurality of perforations made in the body such that the perforations do not form communicating channels within the body and wherein said perforations allow for transport of ions through the element;
- (d) a variable field shaping element positioned between the ionically resistive ionically permeable element and the position of the substrate holder;
- and
- (e) a first auxiliary cathode located between the anode and the ionically resistive ionically permeable element, and peripherally oriented to shape the current distribution from the anode, while the first auxiliary cathode is supplied with current during electroplating
- (f) a second auxiliary cathode positioned to be located between the ionically resistive ionically permeable element and the substrate during electroplating, wherein the second auxiliary cathode is adapted to divert a portion of ionic current from an edge region of the substrate.
4 more elements
Dependencies are inferred from the claim text.