Magnetic shunting pads for optimizing target erosion in sputtering processes
View Patent ↗Magnetic flux shunting pads for optimizing target erosion in sputtering processes are provided. In one embodiment, the invention relates to a sputtering system for countering uneven wear of a sputter target, the system including a sputter target having an emitting surface and a rear surface opposite to the emitting surface, a moving magnet assembly positioned proximate the rear surface and including a planar base and a magnet fixed to the planar base at a preselected point, the moving magnet assembly configured to be moved such that a position of the magnet relative to the rear surface is varied, and a magnetic shunting pad having a planar shape and positioned between the moving magnet assembly and the target, wherein the shunting pad includes uneven magnetic shunting characteristics.
1. A sputtering system for countering uneven wear of a sputter target, the system comprising:
a sputter target having an emitting surface and a rear surface opposite to the emitting surface;
a moving magnet assembly positioned proximate the rear surface and comprising a planar base and a magnet fixed to the planar base at a preselected point, the moving magnet assembly configured to be moved such that a position of the magnet relative to the rear surface is varied;
a magnetic shunting pad having a planar shape and positioned between the moving magnet assembly and the target, wherein the shunting pad comprises two zones comprising different materials and correspondingly different magnetic pass through flux characteristics; and
a backing plate positioned between the magnetic shunting pad and the target.
2. The sputtering system of claim 1 , wherein the magnetic shunting pad comprises:
a first zone having a first magnetic pass through flux characteristic; and
a second zone having a second magnetic pass through flux characteristic greater than the first magnetic pass through flux characteristic.
3. The sputtering system of claim 2 , wherein the magnetic shunting pad comprises a third zone having a third magnetic pass through flux characteristic greater than the first magnetic pass through flux characteristic and less than the second magnetic pass through flux characteristic.
4. The sputtering system of claim 3 , wherein the first pass through flux characteristic is less than about 10 percent flux passage, wherein the third pass through flux characteristic is about 45 to about 65 percent flux passage, and wherein the second pass through flux characteristic is about 95 to about 100 percent flux passage.
5. The sputtering system of claim 3 :
wherein the first zone comprises one or more materials selected from the group consisting of Ni, W, Al, Fe, Co, Zr, B, and Cu;
wherein the third zone comprises one or more materials selected from the group consisting of Ni, W, Al, Fe, Co, and Ta; and
wherein the second zone comprises one or more materials selected from the group consisting of Ni and W.
6. The sputtering system of claim 2 , wherein the first pass through flux characteristic is less than about 10 percent passage, wherein the second pass through flux characteristic is about 95 to about 100 percent passage.
7. The sputtering system of claim 2 , wherein the first pass through flux characteristic is about 1 percent passage, wherein the second pass through flux characteristic is about 100 percent passage.
8. The sputtering system of claim 1 , wherein the target comprises a predetermined erosion pattern, and wherein the magnetic shunting pad comprises a magnetic shunting pattern corresponding to the predetermined erosion pattern and is configured to cause a erosion pattern on the target more uniform than the predetermined erosion pattern.
9. The sputtering system of claim 8 , wherein the magnetic shunting pad comprises:
a first zone having a first magnetic pass through flux characteristic; and
a second zone having a second magnetic pass through flux characteristic greater than the first magnetic pass through flux characteristic,
wherein the predetermined erosion pattern of the target comprises a first target area having higher erosion than other areas of the target, and
wherein the first zone is aligned with the first target area.
10. The sputtering system of claim 9 , wherein the magnet is aligned with the first zone.
11. The sputtering system of claim 1 , wherein the magnetic shunting pad comprises a disk shape.
12. The sputtering system of claim 11 , wherein the magnetic shunting pad comprises:
a first zone having a first magnetic pass through flux characteristic; and
a second zone having a second magnetic pass through flux characteristic greater than the first magnetic pass through flux characteristic,
wherein the first zone comprises an annular ring along the disk shape,
wherein the second zone comprises two annular rings along the disk shape, wherein each of the two annular rings of the second zone is adjacent to the annular ring of the first zone.
13. The sputtering system of claim 11 , wherein the magnetic shunting pad comprises:
a first zone having a first magnetic pass through flux characteristic;
a second zone having a second magnetic pass through flux characteristic greater than the first magnetic pass through flux characteristic; and
a third zone having a third magnetic pass through flux characteristic greater than the first magnetic pass through flux characteristic and less than the second magnetic pass through flux characteristic,
wherein the first zone comprises an annular ring along the disk shape,
wherein the third zone comprises an annular ring along the disk shape having a diameter less than a diameter of the annular ring the first zone,
wherein the second zone comprises two annular rings along the disk shape, wherein each of the two annular rings is adjacent to the annular ring of the first zone.
14. The sputtering system of claim 11 , wherein the second zone further comprises a circular area positioned within the annular ring of the third zone.
15. The sputtering system of claim 1 , wherein the target, the planar base of the moving magnet assembly, and the magnetic shunting pad each comprise a disk shape.
16. The sputtering system of claim 1 , wherein the moving magnet assembly is configured to rotate about a central point of the planar base.
17. The sputtering system of claim 16 , wherein the magnet is fixed to the planar base at a preselected distance from the central point.
18. The sputtering system of claim 16 , wherein the magnet is configured to be rotated in a plane parallel to the rear surface of the target.
19. The sputtering system of claim 1 , wherein the magnetic shunting pad is coupled to the rear surface of the target.
20. The sputtering system of claim 1 , wherein the magnetic shunting pad abuts the backing plate.
21. The sputtering system of claim 1 , wherein the magnetic shunting pad abuts the backing plate which is coupled to the rear surface of the target.
22. The sputtering system of claim 1 , wherein the planar shaped shunting pad comprises a magnetic shunting gradient taken along a surface of the planar shaped shunting pad which provides uneven magnetic shunting characteristics.
23. The sputtering system of claim 1 , further comprising a first intervening layer positioned between the backing plate and the magnetic shunting pad.
24. The sputtering system of claim 23 , further comprising:
a graphite sheet; and
a second intervening layer sandwiched between the magnetic shunting pad and the graphite sheet.
25. The sputtering system of claim 24 , wherein the first intervening layer and the second intervening layer each comprise graphite.
26. The sputtering system of claim 23 , wherein the first intervening layer comprises graphite.