Geometry and process optimization for ultra-high RPM plating

Patent metadata

Field	Value
Publication number	US-9481942-B2
Application number	US-201514613306-A
Country	US
Kind code	B2
Filing date	Feb 3, 2015
Priority date	Feb 3, 2015
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

Various embodiments herein relate to methods and apparatus for electroplating metal onto substrates. The apparatus used to practice electroplating may be designed to have a geometric configuration that makes it difficult for air to travel and become trapped under the substrate. By using such apparatus, electroplating can occur at higher rates of substrate rotation than would otherwise be acceptable. The higher rate of substrate rotation allows electroplating to occur at higher limiting currents, which in turn increases throughput. The disclosed embodiments are particularly useful in the context of electrolytes that otherwise exhibit a relatively low limiting current (e.g., electrolytes having a low concentration of metal ions), though the embodiments are not so limited.

First claim

What is claimed is:

1. An apparatus for electroplating metal onto a substrate, the apparatus comprising:
a substrate support for supporting the substrate at its periphery, wherein when the substrate is present in the substrate support, a plating face of the substrate is held in a substrate plating plane;
a plating gap formed below the substrate plating plane and above an opposing surface positioned under the substrate plating plane;
a pump for delivering electrolyte such that the electrolyte flows into the plating gap;
a peripheral passage positioned radially outside of the substrate support, wherein the peripheral passage has a dimensionless peripheral passage parameter of about 2 or greater, and wherein electrolyte flows through the peripheral passage after the electrolyte exits the plating gap at the periphery of the plating gap and before the electrolyte reaches an electrolyte-air interface; and
a controller having instructions to control electroplating in a manner that does not result in the passage of air through the peripheral passage and under the substrate.

2. The apparatus of claim 1 , wherein the peripheral passage is at least partially defined by the substrate support.

3. The apparatus of claim 1 , wherein the peripheral passage is at least partially defined by a ring positioned radially outside of the substrate support.

4. The apparatus of claim 3 , wherein the ring is a dual cathode clamp ring.

5. The apparatus of claim 3 , wherein the ring is a shielding ring.

6. The apparatus of claim 3 , wherein the ring comprises an electrically insulating material.

7. The apparatus of claim 1 , wherein the peripheral passage has a dimensionless peripheral passage parameter between about 2-10.

8. The apparatus of claim 1 , wherein the peripheral passage has a height of at least about 0.1 inches.

9. The apparatus of claim 1 , the electrolyte-air interface having a resting position when the substrate is not being rotated, wherein a vertical distance between the substrate plating plane and the resting position of the electrolyte-air interface is at least about 10 mm.

10. The apparatus of claim 1 , wherein the peripheral passage is annularly shaped.

11. The apparatus of claim 1 , wherein the opposing surface positioned under the substrate plating plane is a surface of a channeled ionically resistive plate (CIRP), the CIRP comprising a plurality of through-holes, the apparatus further comprising an inlet above the CIRP for providing electrolyte to the plating gap and an outlet above the CIRP for receiving electrolyte from the plating gap, the inlet and outlet each extending between about 90-180° around the plating gap, the inlet and outlet positioned on opposite sides of the plating gap, wherein the peripheral passage is positioned proximate the outlet.

12. The apparatus of claim 11 , wherein the peripheral passage is not annularly shaped.

13. The apparatus of claim 1 , wherein the plating gap has a height between about 0.5-6 mm.

14. The apparatus of claim 1 , wherein the electrolyte follows a flow path after exiting the plating gap and before reaching the electrolyte-air interface, the flow path having a tortuosity of at least about 1.1.

15. The apparatus of claim 1 , wherein the peripheral passage is at least partially defined between a first surface that is substantially stationary during electroplating and a second surface that rotates during electroplating.

16. The apparatus of claim 1 , further comprising a substrate rotation mechanism for rotating the substrate within the substrate plating plane, wherein the controller has instructions to rotate the substrate within the substrate plating plane via the substrate rotation mechanism.

17. The apparatus of claim 1 , wherein the opposing surface positioned under the substrate plating plane is a surface of a channeled ionically resistive plate (CIRP), the CIRP comprising a plurality of through-holes, wherein the pump delivers electrolyte such that the electrolyte passes from below the CIRP, through the through-holes in the CIRP, and into the plating gap.

18. The apparatus of claim 17 , wherein at least a portion of the through-holes are oriented at a non-normal angle with respect to the substrate plating plane.

19. A method of electroplating metal onto a substrate, the method comprising:
positioning the substrate in a substrate support;
immersing the substrate in electrolyte in an electroplating chamber;
supplying current to cause metal to electroplate onto the substrate;
flowing electrolyte into a plating gap defined between the substrate and an opposing surface positioned under the substrate such that the electrolyte impinges upon the substrate, and flowing electrolyte from a periphery of the plating gap through a peripheral passage positioned radially outside of the substrate support, wherein electrolyte flows through the peripheral passage before reaching an electrolyte-air interface, wherein the peripheral passage has a dimensionless peripheral passage parameter of at least about 2;
wherein during electroplating, air does not travel through the peripheral passage and under the substrate.

20. The method of claim 19 , wherein the peripheral passage is at least partially defined by the substrate support.

21. The method of claim 19 , wherein the peripheral passage is at least partially defined by a ring positioned radially outside of the substrate support.

22. The method of claim 21 , wherein the ring is a dual cathode clamp ring.

23. The method of claim 21 , wherein the ring is a shielding ring.

24. The method of claim 19 , wherein the opposing surface positioned under the substrate is a surface of a channeled ionically resistive plate (CIRP), the CIRP comprising a plurality of through-holes, wherein electrolyte flows from below the CIRP, through the through-holes of the CIRP, and into the plating gap.

25. The method of claim 24 , wherein at least a portion of the through-holes are oriented at a non-normal angle with respect to the substrate.

26. The method of claim 19 , wherein the substrate is rotated during electroplating.

Assignees

• Lam Res Corp

Inventors

• Zhou Jian
• Sweeney Cian
• He Zhian
• Reid Jonathan David

Classifications

• C25D5/04

  Electroplating with moving electrodes · CPC title

• C25D21/12

  Process control or regulation (controlling or regulating in general G05) · CPC title

• C25D17/001

  Apparatus specially adapted for electrolytic coating of wafers, e.g. semiconductors or solar cells · CPC title

• C25D17/06

  Suspending or supporting devices for articles to be coated · CPC title

• C25D5/08 Primary

  Electroplating with moving electrolyte e.g. jet electroplating {(using locally applied jets of electrolyte C25D5/026)} · CPC title