Method and apparatus for use in generating plasma
A method of generating a plasma is provided. The method uses a plasma antenna having a length, the method including driving an electrical conductor of the plasma antenna with RF frequency current to generate plasma both at a first location and at a second location spaced apart from the first location in a direction along the length of the antenna, there being a region adjacent to the antenna between the first location and the second location at which the generation of plasma is curtailed as a result of at least one shield member.
1. A method of generating a plasma with the use of a plasma antenna having a length, the method including driving an electrical conductor of the plasma antenna with RF frequency current to generate plasma both at a first location and at a second location spaced apart from the first location in a direction along the length of the antenna, there being a region adjacent to the antenna between the first location and the second location at which the generation of plasma is curtailed as a result of at least one shield member;
wherein the at least one shield member restricts the generation of plasma at a further region that is on the opposite side of the first location from the second location, in the direction along the length of the antenna, or on the opposite side of the second location from the first location, in the direction along the length of the antenna.
2. The method according to claim 1 , wherein the plasma generated at one or both of the first location and the second location extends circumferentially around the antenna by more than 300 degrees.
3. The method according to claim 1 , wherein the plasma generated at one or both of the first location and the second location extends circumferentially around the antenna by less than 270 degrees.
4. The method according to claim 1 , wherein the at least one shield member restricts the generation of plasma circumferentially around the antenna by more than 300 degrees.
5. The method according to claim 1 , wherein the at least one shield member restricts the generation of plasma on circumferentially around the antenna by less than 270 degrees.
6. The method according to claim 1 , wherein the at least one shield member restricts the generation of plasma at one or both of the first location and the second location.
7. The method according to claim 1 , wherein the at least one shield member restricts the generation of plasma at a further region that is on the opposite side of the first location from the second location, in the direction along the length of the antenna, or on the opposite side of the second location from the first location, in the direction along the length of the antenna.
8. The method according to claim 1 , wherein the at least one shield member comprises material that has a relative magnetic permeability of less than 100.
9. The method according to claim 1 , wherein the at least one shield member is in the form of a partial or complete Faraday cage.
10. The method according to claim 1 , wherein the at least one shield member comprises an electromagnetic-shielding electrically conductive material.
11. The method according to claim 1 , wherein the at least one shield member is held at a fixed potential.
12. The method according to claim 1 , wherein the at least one shield member comprises dielectric material.
13. The method according to claim 1 , wherein the antenna creates a magnetic field which is enhanced and/or focussed by a plasma focussing member, which comprises ferromagnetic material.
14. The method according to claim 1 , wherein the antenna is at least partly contained within an air-tight tube of material.
15. The method according to claim 14 , wherein the at least one shield member is mounted externally of the air-tight tube of material.
16. The method according to claim 1 , wherein the length of the antenna between the first and second locations is linear.
17. The method according to claim 1 , wherein the method includes generating plasma with the use of at least two lengths of plasma antenna being spaced laterally apart from each other.
18. The method according to claim 1 , wherein the method includes confining the plasma so as to cause interaction between the plasma and a target.
19. A plasma antenna for use in the method of claim 1 , the antenna being provided together with said at least one shield member, the antenna and said at least one shield member together forming a plasma antenna assembly.
20. A plasma reactor comprising one or more plasma antenna assemblies according to claim 19 .
21. The plasma reactor according to claim 20 , wherein the plasma antenna is configured to generate a plasma remote from a sputter target.
22. A deposition apparatus comprising one or more plasma antenna assemblies according to claim 19 .
23. A method of depositing a material on a substrate, the method comprising:
generating a plasma remote from one or more sputter targets suitable for plasma sputtering using a plasma antenna having a length, by driving an electrical conductor of the plasma antenna with RF frequency current to generate plasma both at a first location and at a second location spaced apart from the first location in a direction along the length of the antenna, there being a region adjacent to the antenna between the first location and the second location at which the generation of plasma is curtailed as a result of at least one shield member,
generating sputtered material from the one or more sputter targets using the plasma; and
depositing the sputtered material onto the substrate.
24. The method according to claim 23 , wherein the step of generating sputtered material from the target or targets using the plasma includes confining and/or controlling, with the use of an electric field and/or a magnetic field, the plasma in such a way that the plasma sputters material from a target.
25. The method according to claim 23 , wherein the plasma has uniform density at the target as a result, at least in part, of the use of the at least one shield member.
26. An electronic device comprising a component which comprises a layer of material deposited using the method of claim 23 .
27. The electronic device according to claim 26 , wherein the component includes the substrate onto which the layer of material has been deposited.
28. A plasma antenna assembly, the assembly comprising an antenna and a housing, wherein
the antenna has a length,
the antenna is configured, when powered by RF frequency current, to generate plasma both at a first location and at a second location spaced apart from the first location in a direction along the length of the antenna, and
the housing has at least one shield member which is arranged such that there is a region adjacent to the antenna between the first location and the second location at which, in use, the generation of plasma is inhibited as a result of said at least one shield member;
wherein the at least one shield member is configured to restrict the generation of plasma at a further region that is on the opposite side of the first location from the second location, in the direction along the length of the antenna, or on the opposite side of the second location from the first location, in the direction along the length of the antenna.