Method and apparatus for treating surface including virtual anode
AssigneeNovellus Systems, Inc.
InventorsJonathan David Reid, Steve Taatjes
Life of this patent
Estimating the term…
Abstract
An apparatus for depositing an electrical conductive layer on the surface of a wafer includes a virtual anode located between the actual anode and the wafer. The virtual anode modifies the electric current flux and plating solution flow between the actual anode and the wafer to thereby modify the thickness profile of the deposited electrically conductive layer on the wafer. The virtual anode can have openings through which the electrical current flux passes. By selectively varying the radius, length, or both, of the openings, any desired thickness profile of the deposited electrically conductive layer on the wafer can be readily obtained.
Claims34
An apparatus for treating the surface of a substrate comprising:
- a clamshell for holding said substrate;
- a plating bath having a wall section;
- a virtual anode having a periphery secured to said wall section, said virtual anode having at least one opening therein;
- and
- an anode, said virtual anode being located between said clamshell and said anode.
A method of treating a surface of a substrate comprising the steps of:
- providing a clamshell, an anode, a virtual anode, and a plating bath containing a plating solution;
- mounting said substrate in said clamshell;
- placing said clamshell and said substrate in said plating solution;
- and
- generating an electric current flux between said surface of said substrate and said anode, wherein said electric current flux passes through said virtual anode, said virtual anode shaping said electric current flux according to a distance between said virtual anode and said substrate.
A method of treating a surface of a substrate comprising:
- providing a clamshell an anode a virtual anode having a plurality of openings therein, a first opening of said plurality of openings having a greater length than a second opening of said plurality of openings, and a plating bath containing a plating solution;
- mounting said substrate in said clamshell;
- placing said clamshell and said substrate in said plating solution;
- and
- generating an electric current flux between said surface of said substrate and said anode, wherein said electric current flux passes through said plurality of openings and thereby through said virtual anode, a greater percentage of said electric current flux passing through said second opening than through said first opening, said virtual anode shaping said electric current flux.
A method of electroplating a metallic layer on a substrate comprising:
- immersing said substrate in an electroplating solution;
- immersing an anode in said solution;
- applying a positive voltage to said anode and a negative voltage to said substrate;
- interposing a virtual anode in said electroplating solution between said anode and said substrate, said virtual anode comprising at least a first opening and a second opening;
- and
- causing said first opening to have a first width and a first length and said second opening to have a second width and a second length so as to produce a particular thickness profile of said metallic layer, said thickness profile being determined at least in part by said first and second widths and said first and second lengths.
An electroplating system for semiconductor wafers comprising:
- a power supply having a negative terminal and a positive terminal;
- a semiconductor wafer electrically connected to the negative terminal;
- a plating bath holding a plating solution;
- an anode positioned in the plating solution and electrically connected to the positive terminal;
- a nonconductive virtual anode positioned in the plating solution between the anode and the wafer, the virtual anode being in the form of an annulus having a central aperture with a diameter that is less than a diameter of the anode.
A method of electroplating a layer of metal on a semiconductor wafer comprising:
- immersing the wafer in a plating solution;
- immersing an anode in the plating solution;
- applying a negative voltage to the wafer and applying a positive voltage to the anode;
- and
- positioning a virtual anode between the anode and the wafer, the virtual anode being in the form of an annulus having a central aperture with a diameter less than a diameter of the wafer such that the virtual anode functions to limit a flow of current to an edge region of the wafer.
Dependencies are inferred from the claim text.