Sputtering target including a feature to reduce chalcogen build up and arcing on a backing tube
View Patent ↗A sputtering target has a cylindrical backing tube having two edges and a sidewall comprising a middle portion located between two end portions. The sputtering material is on the backing tube. The sputtering material does not cover at least one end portion of the backing tube. The sputtering target also has a feature which prevents or reduces at least one of chalcogen buildup and arcing at the at least one end portion of the backing tube not covered by the sputtering material.
1. A sputtering target, comprising:
a cylindrical backing tube having two edges and a sidewall comprising a middle portion located between two end portions;
a copper indium gallium sputtering material contacting the middle portion of the sidewall of the backing tube, wherein the sputtering material does not cover at least one end portion of the sidewall of the backing tube; and
a thermally insulating feature in contact with the at least one end portion of the sidewall of the backing tube, which prevents or reduces a chalcogen buildup and arcing at the at least one end portion of the backing tube not covered by the sputtering material, the thermally insulating feature comprising a dielectric material portion that has a different composition from the copper indium gallium sputtering material,
wherein the chalcogen comprises selenium, sulfur or a combination thereof.
2. The sputtering target of claim 1 , wherein the sputtering target is incorporated into a sputtering apparatus that includes:
a chamber for containing the sputtering target;
a sputtering source that comprises a magnetron configured to be located inside the backing tube; and
a chalcogen source which provides the chalcogen in the chamber.
3. The sputtering target of claim 1 , wherein the backing tube comprises steel.
4. The sputtering target of claim 1 , wherein the sputtering material includes chalcogen.
5. The sputtering target of claim 1 , wherein the thermally insulating feature comprises a dielectric coating on the at least one end portion of the backing tube.
6. The sputtering target of claim 5 , wherein the sputtering target is located in a reactive sputtering chamber having a chalcogen source, and the dielectric coating prevents chalcogen from contacting the at least one end portion of the backing tube.
7. The sputtering target of claim 6 , wherein the dielectric coating comprises a polymer, a glass, a ceramic, or a crystalline electrical non-conductor.
8. The sputtering target of claim 6 , wherein:
the dielectric coating is applied as a tape on the end portion of the backing tube; or
the dielectric coating is applied via an adhesive on end portion of the backing tube; or
the dielectric coating comprises at least a portion of a sleeve which is disposed on the end portion of the backing tube; or
the dielectric coating is formed as a thin film on the end portion of the backing tube.
9. The sputtering target of claim 6 , wherein the dielectric coating comprises a thin film formed by at least one of physical vapor deposition, chemical vapor deposition, oxidation of the backing tube, and anodization of the backing tube.
10. The sputtering target of claim 1 , further comprising a heated shield adjacent to the thermally insulating feature and the at least one end portion of the backing tube.
11. The sputtering target of claim 10 , wherein the shield is spaced from the thermally insulating feature and the end portion of the backing tube and extends adjacent to an edge of the sputtering material.
12. The sputtering target of claim 11 , wherein the shield comprises a stationary shield or a rotating shield.
13. The sputtering target of claim 12 , wherein a stationary heater is located adjacent to the rotating shield.
14. The sputtering target of claim 11 , wherein an embedded heater is located in the shield, a heater is attached to the shield, or the shield is made of a resistance heater material.
15. The sputtering target of claim 14 , wherein the shield is a rotating shield and the heater comprises a rotary electrical connection.
16. The sputtering target of claim 1 , further comprising: a heater or a heat lamp directed at the thermally insulating feature and the end portion of the backing tube.
17. The sputtering target of claim 1 , further comprising: a heater located adjacent to the thermally insulating feature and the end portion of the backing tube, and wherein the heater is configured to rotate with the backing tube.
18. The sputtering target of claim 1 , wherein the thermally insulating feature comprises a thermally insulating material layer inside the backing tube at the end portion of the backing tube but not at the middle portion of the backing tube.
19. The sputtering target of claim 18 , wherein the thermally insulating material comprises a tape, a thin film, or an epoxy layer which reduces effect of cooling water inside the backing tube on the end portion of the backing tube.
20. The sputtering target of claim 1 , wherein the thermally insulating feature comprises a thermally insulating material located between an end portion of the sputtering material and the backing tube.
21. The sputtering target of claim 1 , further comprising a ring shaped shield having poor thermal contact to the sputtering material or to the end portion of the backing tube, wherein the shield covers the thermally insulating feature and the end portion of the backing tube.
22. The sputtering target of claim 21 , wherein the shield sets off a dark space at the end portion of the backing tube.
23. The sputtering target of claim 22 , wherein the shield comprises an aluminum ring or a copper ring and the sputtering material comprises a copper indium gallium sputtering material.