Extending lifetime of yttrium oxide as a plasma chamber material

• US 20080169588A1
• Filed: 01/11/2007
• Published: 07/17/2008
• Est. Priority Date: 01/11/2007
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Liu, Shenjian, Shih, Hong, Daugherty, John, Outka, Duane
• Granted Patent: US 8,097,105 B2
• Time in Patent Office: Days
• US Class Current: 264/423
• CPC Class Codes: H01J 37/32467 Material
• CPC Class Codes: H01J 37/32495 Means for protecting the vessel against plasma
• CPC Class Codes: H01J 9/24 Manufacture or joining of vessels, leading-in conductors or bases
• CPC Class Codes: Y10T 29/4973 Replacing of defective part

Abstract

Two methods of extending the lifetime of yttrium oxide as a plasma chamber material are provided. One method comprises making a three-layer component of a plasma processing chamber by co-sintering a dual-layer green body where one layer comprises ceramic particles and a second layer comprises yttria particles. The two layers are in intimate contact during the sintering process. In a preferred embodiment, the three layer component comprises an outer layer of yttria, an intermediate layer of YAG, and a second outer layer of alumina. Optionally, the disks are pressed together during the sintering process. The resulting three-layer component is very low in porosity. Preferably, the porosity of any of the outer layer of yttria, the intermediate layer of YAG, and the second outer layer of alumina, is less than 3%. The second method comprises sealing an yttria plasma spray coated component by applying a liquid anaerobic sealant with a room temperature viscosity of less than 50 cP to the component by brushing the sealant on all yttria surfaces of the component, wet cleaning the component, curing the wet cleaned component for over 2 hours at a temperature of at least 150° C. in an N2 environment; and, applying a second sealant coat to the cured substrate by repeating the procedure used to apply the first coat.

Claims

1. A method of making a three-layer component of a plasma processing chamber comprising:

a. forming a dual-layer green body by

i. pressing together a first layer and a second layer

ii. machining the pressed together layers to the desired dimensions;

wherein the first layer comprises alumina particles and the second layer comprises yttria particles; and

b. co-sintering the dual-layer green body, wherein the first layer and the second layer are in intimate contact during the sintering process;

so as to form a three-layer component, comprising an outer layer of alumina adjacent an intermediate layer comprising a solid solution of yttria and alumina, adjacent a second outer layer of yttria.

2. The method of claim 1, wherein the intermediate layer comprises YAG, the first layer comprises a green sheet of alumina and the second layer comprises a green sheet of yttria.

3. The method of claim 1, wherein the porosity of any of the outer layer of yttria, the intermediate layer, and the outer layer of alumina is less than 3%.

4. The method of claim 1, wherein the porosity of any of the outer layer of yttria, the intermediate layer, and the outer layer of alumina is less than 1%.

5. The method of claim 1, wherein the first layer and second layer are hot isostatically pressed together during the co-sintering process.

6. The method of claim 1, wherein the first layer and the second layer of the green body are disk-shaped, with a smooth surface and a diameter of at least the desired final diameter, and wherein the green body consists essentially of the first and second layer.

7. The method of claim 1, wherein the three layer component forms a dielectric RF transmitting window.

8. The method of claim 7, wherein the first layer of the green body has a thickness of from about 20 mm to about 40 mm, and the second layer of the green body has a thickness of from about 1 mm to about 9 mm.

9. The method of claim 7, wherein the outer layer of yttria of the three-layer component has a thickness of from about 1 mm to about 5 mm, the intermediate layer of the three-layer component has a thickness of from about 2 mm to about 6 mm, and the outer layer of alumina of the three-layer component has a thickness of from about 15 mm to about 45 mm.

10. The method of claim 1, wherein the three-layer component is selected from the group consisting of a chamber wall, a chamber liner, a substrate support a baffle, a gas distribution plate, a plasma confinement ring, a nozzle, a plasma focus ring, a hot edge ring, a coupling ring, a chuck, a fastener and/or heating element of a plasma processing apparatus.

11. A method of installing a component of a plasma processing chamber comprising removing a component from within the chamber and replacing it with a component made according to the method of claim 1, wherein the component is installed such that when the chamber is in operation so as to create a plasma environment, the second outer layer of yttria has at least one surface exposed to the plasma environment.

12. The method of claim 11, wherein the plasma processing chamber is a conductor etch chamber.

13. The method of claim 11, wherein the three-layer component has improved resistance to peeling compared to thermally sprayed yttria coatings

14. A method of plasma processing a semiconductor substrate comprising processing the substrate in the plasma processing chamber of claim 11.

16. The method of claim 13, wherein the sealant contains Tetraethylene glycol dimethacrylate, 2-Hydroxyethyl methacrylate, Saccharin, Cumene hydroperoxide, and Methacrylic acid.

15. A method of sealing an yttria plasma spray coated component of a plasma processing chamber, the method comprising;

a) applying a liquid anaerobic sealant with a room temperature viscosity of less than 50 cP to the surfaces of all yttria layers of the component;

b) wet cleaning the component;

c) curing the wet cleaned component for over 2 hours at a temperature of at least 150°

C. in an N₂ environment; and

,

d) applying a second liquid anaerobic sealant to the cured substrate by repeating using the same procedure as in a) through c).

17. The method of claim 15, wherein the resistivity of each sealed yttria plasma spray coated layer is greater than ten times the resistivity of each respective unsealed layer.

18. The method of claim 15, wherein the sealant effectively penetrates through the entire yttria layer.

19. A method of plasma processing comprising processing a semiconductor substrate in a plasma processing chamber, the chamber comprising an yttria plasma spray coated component sealed by the method of claim 15.