Method and apparatus for electroplating
AssigneeNovellus Systems, Inc.
InventorsSteven Mayer, Jingbin Feng, Zhian He, Jonathan Reid, Seshasayee Varadarajan
Life of this patent
Estimating the term…
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
A method of plating a metal layer onto a substrate, the method comprising:
- (a) holding a substrate, having a working surface comprising a conductive layer, in a substrate holder of an electroplating apparatus, wherein the apparatus comprises a plating chamber, an anode, 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 the working surface 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;
- (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 conductive layer of the substrate;
- (d) supplying current to the first 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 ionically resistive ionically permeable element and the substrate during electroplating to divert a portion of ionic current from an edge region of the substrate.
Dependencies are inferred from the claim text.