Rotationally asymmetric variable electrode correction
AssigneeNovellus Systems, Inc.
InventorsSteven T. Mayer, John S. Drewery
Life of this patent
Estimating the term…
Abstract
A work piece is electroplated or electroplanarized using an azimuthally asymmetric electrode. The azimuthally asymmetric electrode is rotated with respect to the work piece (i.e., either or both of the work piece and the electrode may be rotating). The azimuthal asymmetry provides a time-of-exposure correction to the current distribution reaching the work piece. In some embodiments, the total current is distributed among a plurality of electrodes in a reaction cell in order to tailor the current distribution in the electrolyte over time. Focusing elements may be used to create “virtual electrode” in proximity to the surface of the work piece to further control the current distribution in the electrolyte during plating or planarization.
Claims41
A method of electrochemically processing a metal layer on a work piece, the method comprising:
- (a) providing a reactor comprising an azimuthally asymmetric electrode;
- (b) providing the work piece in the reactor at a position substantially aligned with the azimuthally asymmetric electrode;
- (c) rotating at least one of the work piece and the azimuthally asymmetric electrode with respect to the other;
- and
- (d) electrochemically processing the metal layer on the work piece while rotating to thereby provide a radially varying source of current over the period of rotation.
An apparatus for electrochemically processing a metal layer on a work piece, the apparatus comprising:
- (a) a reactor chamber;
- (b) an azimuthally asymmetric electrode in the reactor chamber;
- (c) a work piece holder for holding the work piece in the reactor at a position substantially in alignment with the azimuthally asymmetric electrode;
- and
- (d) a mechanism for rotating at least one of the work piece and the azimuthally asymmetric electrode with respect to the other.
A method of electroplating a layer of a metal onto a work piece, the method comprising:
- (a) providing a reactor comprising an azimuthally asymmetric anode;
- (b) providing the work piece in the reactor at a position substantially aligned with the azimuthally asymmetric anode;
- (c) rotating at least one of the work piece and the azimuthally asymmetric anode with respect to the other while contacting a plating solution containing ions of the metal;
- and
- (d) plating metal onto the work piece while rotating to thereby provide a radially varying source of current.
A method of electrolytically removing material from the surface of a work piece, the method comprising:
- (a) providing a reactor comprising an azimuthally asymmetric cathode;
- (b) providing the work piece in the reactor at a position substantially aligned with the azimuthally asymmetric cathode;
- and
- (c) rotating at least one of the work piece and the azimuthally asymmetric cathode with respect to the other while contacting an electrolyte to provide a radially varying current distribution at work piece and thereby electrolytically removing material from the work piece.
A method of electrochemically processing a work piece having a region that requires more or less processing than at least one other area on the work piece, the method comprising:
- (a) providing a reactor comprising an electrode assembly, the electrode assembly comprising multiple separate electrode segments having distinct radial and/or azimuthal positions;
- (b) providing work piece in the reactor at a position substantially aligned with the electrode assembly;
- (c) rotating at least one of the work piece and the electrode assembly with respect to the other;
- and
- (d) during rotation, sequentially adjusting the current and/or voltage provided to individual electrode segments in the assembly in a manner that follows the period of rotation and tracks the region on the work piece requiring more or less processing than at least one other area on the work piece.
Dependencies are inferred from the claim text.