ELECTROPLATING APPARATUS FOR TAILORED UNIFORMITY PROFILE

• US 20120258408A1
• Filed: 04/03/2012
• Published: 10/11/2012
• Est. Priority Date: 11/07/2008
• Status: Active Grant

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: MAYER, Steven T., PORTER, David W., BUCKALEW, Bryan L., RASH, Robert
• Granted Patent: US 8,858,774 B2
• Time in Patent Office: Days
• US Class Current: 430/325
• CPC Class Codes: C25D 17/001 Apparatus specially adapted for electrolytic coating of wafers, e.g. semiconductors or solar cells
• CPC Class Codes: C25D 17/002 Cell separation, e.g. membranes, diaphragms
• CPC Class Codes: C25D 17/007 Current directing devices
• CPC Class Codes: C25D 17/008 Current shielding devices
• CPC Class Codes: C25D 17/06 Suspending or supporting devices for articles to be coated
• CPC Class Codes: C25D 17/12 Shape or form C25D17/14 takes precedence
• CPC Class Codes: C25D 21/10 Agitating of electrolytes; Moving of racks
• CPC Class Codes: C25D 21/12 Process control or regulation controlling or regulating in general G05
• CPC Class Codes: C25D 5/04 Electroplating with moving electrodes
• CPC Class Codes: C25D 5/18 Electroplating using modulated, pulsed or reversing current
• CPC Class Codes: C25D 7/123 Semiconductors first coated with a seed layer or a conductive layer
• CPC Class Codes: H01L 21/2885 using an external electrical current, i.e. electro-deposition
• CPC Class Codes: H01L 21/76873 for electroplating

Abstract

Methods of electroplating metal on a substrate while controlling azimuthal uniformity, include, in one aspect, providing the substrate to the electroplating apparatus configured for rotating the substrate during electroplating, and electroplating the metal on the substrate while rotating the substrate relative to a shield such that a selected portion of the substrate at a selected azimuthal position dwells in a shielded area for a different amount of time than a second portion of the substrate having the same average arc length and the same average radial position and residing at a different angular (azimuthal) position. For example, a semiconductor wafer substrate can be rotated during electroplating slower or faster, when the selected portion of the substrate passes through the shielded area.

Claims

1. A method of electroplating a metal on a cathodically biased substrate while controlling azimuthal uniformity, the method comprising:

(a) providing the substrate into an electroplating apparatus configured for rotating the substrate during electroplating, wherein the apparatus comprises an anode and a stationary auxiliary azimuthally asymmetric electrode; and

(b) electroplating the metal on the substrate while rotating the substrate, and while providing power to the auxiliary azimuthally asymmetric electrode in correlation with the rotation of the substrate, such that the auxiliary azimuthally asymmetric electrode diverts and/or donates plating current to a first portion of the substrate at a selected azimuthal position of the substrate differently than to a second portion of the substrate having the same average arc length and the same average radial position and residing at a different azimuthal angular position.

16. The method of claim 1, further comprising the steps of:

applying photoresist to the substrate;

exposing the photoresist to light;

patterning the resist and transferring the pattern to the substrate;

and selectively removing the photoresist from the substrate.

2-12. -12. (canceled)

13. An electroplating apparatus for electroplating a metal on a substrate, the apparatus comprising:

(a) a plating chamber configured to contain an electrolyte, an anode, and an azimuthally asymmetric auxiliary electrode;

(b) a substrate holder configured to hold the substrate; and

(c) a controller comprising program instructions for electroplating the metal on the substrate while rotating the substrate, and while providing power to the auxiliary azimuthally asymmetric electrode in correlation with the rotation of the substrate, such that the auxiliary azimuthally asymmetric electrode diverts and/or donates plating current to a first portion of the substrate at a selected azimuthal position of the substrate differently than to a second portion of the substrate having the same average arc length and the same average radial position and residing at a different angular azimuthal position.

14. A system comprising an apparatus of claim 13 and a stepper.

44. The apparatus of claim 13, wherein the auxiliary azimuthally asymmetric electrode is C-shaped.

45. The apparatus of claim 13, wherein the auxiliary azimuthally asymmetric electrode is in an azimuthal current flow confinement structure.

46. The apparatus of claim 13, wherein the auxiliary azimuthally asymmetric electrode is housed in a separate chamber and the exposure of plating current from the auxiliary electrode is through at least one channel that delivers current into a region of the cell near the periphery of the substrate over an arc angle of less than about 120 degrees.

47. The apparatus of claim 13, wherein the auxiliary azimuthally asymmetric electrode is configured to be cathodically biased and is configured to divert different amounts of plating current from different azimuthal positions of the substrate during electroplating.

48. The apparatus of claim 13, wherein the auxiliary azimuthally asymmetric electrode is configured to be anodically biased and is configured to donate different amounts of plating current to different azimuthal positions of the substrate during electroplating.

49. The apparatus of claim 13, wherein the auxiliary azimuthally asymmetric electrode is configured to be both anodically and cathodically biased during electroplating, and is configured to divert plating current from a first azimuthal position on the substrate and to donate plating current to a second azimuthal position on the substrate.

50. The apparatus of claim 13, wherein the apparatus further comprises a shield, shielding the periphery of the substrate at all azimuthal positions, and wherein the auxiliary azimuthally asymmetric electrode is configured to be anodically biased at least during a portion of a time of a full rotation of the substrate, and is configured to donate current to the selected azimuthal position on the substrate.

51. The apparatus of claim 13, wherein the apparatus is configured such that a distance between the auxiliary azimuthally asymmetric electrode and the substrate in plating position is no greater than 20% of the radius of the substrate.

52. The apparatus of claim 13, further comprising program instructions for:

during electroplating rotating a shield having a generally annular body with a removed segment, wherein the shield is positioned in close proximity of the wafer, and wherein the rotation is not synchronized with the wafer rotation and wherein the rotation optimizes flow of electrolyte in the proximity of the substrate.

15. A non-transitory computer machine-readable medium comprising program instructions for control of an electroplating apparatus, the program instructions comprising code for electroplating the metal on the substrate while rotating the substrate, and while providing power to the auxiliary azimuthally asymmetric electrode in correlation with the rotation of the substrate, such that the auxiliary azimuthally asymmetric electrode diverts and/or donates plating current to a first portion of the substrate at a selected azimuthal position of the substrate differently than to a second portion of the substrate having the same average arc length and the same average radial position and residing at a different angular azimuthal position.

17-20. -20. (canceled)

21. A method of electroplating a metal on a cathodically biased substrate while controlling azimuthal uniformity, the method comprising:

(a) providing the substrate into an electroplating apparatus configured for rotating the substrate during electroplating, wherein the apparatus comprises a first anode and a multi-segmented auxiliary anode or a multi-segmented auxiliary electrode configured to serve both as an auxiliary anode and an auxiliary cathode; and

(b) electroplating the metal on the substrate while rotating the substrate, and while providing power to the segments of the multi-segmented auxiliary anode or the multi-segmented auxiliary electrode in correlation with the rotation of the substrate, such that said anode donates plating current to a first portion of the substrate at a selected azimuthal position of the substrate to a different level than to a second portion of the substrate having the same average arc length and the same average radial position and residing at a different angular azimuthal position, or such that said auxiliary electrode donates current to the first portion and diverts the current from the second portion.

22-33. -33. (canceled)

34. An electroplating apparatus for electroplating a metal on a substrate, the apparatus comprising:

(a) a plating chamber configured to contain an electrolyte and a shield;

(b) a substrate holder configured to hold the substrate; and

(c) a controller comprising program instructions for electroplating the metal on the substrate while rotating the substrate relative to the shield such that a selected portion of the substrate at a selected azimuthal position dwells in a shielded area for a different amount of time than a second portion of the substrate having the same average arc length and the same average radial position and residing at a different angular azimuthal position.

53. The apparatus of claim 34, wherein program instructions comprise instructions for rotating the substrate at a first speed when the selected portion of the substrate is less shielded, and at a second speed when the selected portion of the substrate is more shielded, wherein one full rotation of the substrate comprises a first period of rotation at the first speed and a second period of rotation at the second speed.

54. The apparatus of claim 53, wherein the second speed is lower than the first speed.

55. The apparatus of claim 34, wherein the electroplating apparatus further comprises an ionically resistive ionically permeable element having a flat surface that is configured to be substantially parallel to and separated from the plating face of the substrate by a distance of about 10 millimeters or less during electroplating, wherein the element has a plurality of non-communicating holes.

56. The method of claim 55, wherein the shield is an azimuthally asymmetric shield eclipsing some of the holes of the flow-shaping element or wherein the shield is the ionically resistive ionically permeable element having an azimuthally asymmetric distribution of holes.

35-43. -43. (canceled)