Durable graphite connector and method for manufacturing thereof
View Patent ↗An article comprising a graphite part coated with a pyrolytic graphite (pG) for increased mechanical strength of at least 25% over an uncoated graphite part. In connector applications for use in a semiconductor processing assembly such as a heater, the pG coated component is overcoated with at least a protective layer of an electrically insulating material, and wherein part of the pG coated graphite part is exposed (uncoated with the protective layer) for providing electrical connections to the assembly.
1. A graphite article for use in an assembly for a semi-conductor processing environment, comprising
a graphite core,
a coating layer comprising pyrolytic graphite having an average thickness of 0.001″ to 0.10″,
a protective coating layer disposed on a least a portion of the pyrolytic graphite coating layer, the protective coating layer comprising at least one of a nitride, carbide, carbonitride or oxynitride of elements selected from a group consisting of B, Al, Si, Ga, refractory hard metals, transition metals, and combinations thereof; and
wherein the graphite article has a tensile strength of at least 25% higher than a corresponding graphite article without the pyrolytic graphite coating layer and the protective coating layer.
2. The graphite article of claim 1 , wherein the graphite article has a tensile strength of at least 50% higher than a corresponding graphite article without the pyrolytic graphite coating layer and the protective coating layer.
3. The graphite article of claim 1 , wherein the graphite article has a tensile strength of at least 70% higher than a corresponding graphite article without the pyrolytic graphite coating layer and the protective coating layer.
4. The graphite article of claim 1 , wherein the pyrolytic graphite coating layer has a thickness of 0.005″ to 0.05″.
5. The graphite article of claim 1 , wherein the pyrolytic graphite coating layer has a thickness of 0.0254″ to 0.05″.
6. The graphite article of claim 1 , for use as one of an element support, a support bar, a fixture, a plate, a nut, a rod, a spacer, a bolt, a sleeve, a disc, a tube, a washer, a stud, a gear, a roller, a shaft, a slide plate, a lift off arm, a bearing, a pusher bar, a stopper rod, a connector, a power lead-in, and a slat.
7. The graphite article of claim 1 , wherein the graphite core is hollow having a surface, and wherein at least a portion of the surface on hollow core is coated by at least a layer of a pyrolytic graphite coating layer having an average thickness of 0.001″ to 0.10″.
8. The graphite article of claim 1 , wherein the pyrolytic graphite coating layer is further coated by a protective coating layer comprising at least one of a nitride, carbide, carbonitride or oxynitride of elements selected from a group consisting of B, Al, Si, Ga, refractory hard metals, transition metals, and combinations thereof.
9. The graphite article of claim 1 , wherein the graphite core is hollow, and wherein the graphite article further comprises:
a support member disposed within the hollow core.
10. The graphite article of claim 8 , wherein the support member is a tube comprising metal.
11. The graphite article of claim 1 , for use in a wafer processing apparatus in a chemical vapor deposition furnace, and wherein the graphite article has an oxidation rate of less than 10 nm/min. at a temperature of at least 600° C.
12. The graphite article of claim 1 , wherein the article has an oxidation rate of less than 5 nm/min. at a temperature of at least 600° C.
13. The graphite article of claim 1 , wherein the article has an oxidation rate of less than 2 nm/min. at a temperature of at least 500° C.
14. The graphite article of claim 1 , wherein the protective coating layer comprises one of pyrolytic boron nitride and aluminum nitride.
15. The graphite article of claim 1 , wherein the protective coating layer has a CTE ranging from 2.0×10 −6 /K to 10×10 −6 /K in a temperature range of 25 to 1000° C.
16. The graphite article of claim 1 , wherein at least a portion of the pyrolytic graphite coating layer is exposed and not coated with the protective coating layer, for providing electrical connection with an external power source.
17. The graphite article of claim 1 , in the form of a shaft providing support to a wafer-processing device, wherein:
the shaft has a connection end for connecting with an external power supply to provide electrical connection to the wafer processing device and a base end for providing support for a substrate to support a wafer to be processed;
the shaft is coated with a pyrolytic graphite layer having an average thickness of 0.001″ to 0.10″, having an outer protective layer of a thickness of 2-500 μm comprising least a nitride, carbide, carbonitride or oxynitride of elements selected from a group consisting of B, Al, Si, Ga, refractory hard metals, transition metals, and combinations thereof, the protective layer has a CTE ranging from 2.0×10 −6 /K to 10×10 −6 /K in a temperature range of 25 to 1000° C. at least a portion of the connection end of the shaft is not coated with the protective layer, for the pG coating layer to be exposed for connecting the wafer-processing device with the external power supply.
18. A wafer processing assembly for heating a wafer substrate, the assembly comprises:
an electric heater comprising a graphite substrate having a flat surface for supporting the wafer substrate and at least a support shaft for supporting the flat surface, the support shaft comprises a graphite connector for connecting the electric heater to a power supply means, the graphite connector is coated with at least a layer of pyrolytic graphite having a thickness of 0.001″ to 0.10″, and wherein the graphite connector has a tensile strength of at least 25% higher than a corresponding graphite article without the pG coating layer.
19. The wafer processing assembly of claim 18 , wherein the pG coated graphite connector is further coated with at least a protective coating layer on a least a portion of the graphite coating layer, the protective coating layer comprising at least one of a nitride, carbide, carbonitride or oxynitride of elements selected from a group consisting of B, Al, Si, Ga, refractory hard metals, transition metals, and combinations thereof.
20. The wafer processing assembly of claim 18 , wherein the support shaft further comprising a support member disposed within the shaft, and wherein the support member is a tube comprising metal.
21. A heater assembly for use in semi-conductor processing applications, the assembly comprises:
a heater which is vertically moved in a furnace;
an electrode connected to the heater, the electrode comprises a graphite part which is coated with at least a layer of pyrolytic graphite having a thickness of 0.001″ to 0.01″, and wherein the graphite part has a tensile strength of at least 25% higher than a corresponding graphite part without the pG coating layer.
22. A method for extending the service life of a graphite part in assemblies for use in semi-conductor processing applications, the method comprises:
coating the graphite part with at least a layer of pyrolytic graphite (pG) having a thickness of 0.001″ to 0.10″;
coating at least part of the pG coated graphite with a layer having a thickness of 2-500 μm and comprising least a nitride, carbide, carbonitride or oxynitride of elements selected from a group consisting of B, Al, Si, Ga, refractory hard metals, transition metals, and combinations thereof, for the graphite part to have a tensile strength of at least 25% higher than a corresponding graphite article without the pG coating layer and the outer protective layer.