1. A magnetic transducer element comprising:
a member of magnetizable material having an axis about which it is rotatable or capable of flexing;
wherein said member is a portion of a shaft, and
wherein said member being magnetizable to having a first and a second annulus of axially-directed stored magnetization about said axis extending inwardly from an external surface of said member, the first and second annuli being axially spaced and each annulus of magnetization emanating a magnetic field the distribution of a component of which in the axial direction exhibits a magnetic field profile which shifts in the axial direction as a function of torque applied to said member about said axis andor to a force causing said member to flex about said axis, and
wherein said first annulus exhibits a magnetic field profile of said component which shifts in the opposite direction to the shift of the magnetic field profile of said component exhibited by said second annulus in response to a given torque applied about said axis or to a given force applied to flex said member about said axis.
2. A magnetic transducer element as claimed in claim 1 in which said member is free of resident magnetizations other than the magnetizations of the annuli of magnetization.
3. A magnetic transducer element as claimed in claim 1 in which each annulus of magnetization generates a closed loop of magnetic flux which extends interiorly of the annulus essentially to said axis.
4. A magnetic transducer element as claimed in claim 1 in which the radial depth of each annulus of magnetization is between 30 and 60% of the radius between the axis and said surface.
5. A magnetic transducer element as claimed in claim 1 in which said component of the magnetic field emanated by each annulus is an axially-directed component the magnetic field profile of which shifts in the axial direction as a function of torque over at least a portion of the emanated magnetic field.
6. A magnetic torque transducer element as claimed in claim 1 in which said component of the magnetic field emanated by each annulus is a radial component the magnetic field profile of which shifts in the axial direction as a function of torque over at least a portion of the emanated magnetic field.
7. A magnetic transducer element as claimed in claim 5 wherein the magnetic field profile of said component has pivotal points or regions at or axially beyond the poles of each annulus through which the magnetic field profile passes irrespective of the torque-dependent axial shift.
8. A magnetic transducer element as claimed in claim 1 in which said first annulus of magnetization is created by relative rotation in one direction of said member with respect to means for magnetizing the member and said second annulus of magnetization is created by relative rotation in a direction opposite to said one direction of said member with respect to means for magnetizing the member.
9. A transducer arrangement comprising a magnetic transducer element as claimed in claim 1 and at least one magnetic field sensor located adjacent each annulus of magnetization to sense the field emanated by the respective annulus.
10. A transducer arrangement as claimed in claim 9 in which said at least one magnetic field sensor associated with each annulus has a direction of minimum response in the circumferential or tangential direction.
11. A transducer arrangement as claimed in claim 10 in which the respective at least one magnetic field sensor associated with each annulus has an axis of maximum response which lies in an axial direction or a radial direction.
12. A transducer arrangement as claimed in claim 11 in which the axis of maximum response is in a radial direction and the respective at least one magnetic field sensor is located in alignment with or in the vicinity of the axial center plane of each annulus of magnetization.
13. A transducer arrangement as claimed in claim 11 in which the axis of maximum response is in an axial direction and the respective at least one magnetic field sensor is axially located to one side of the axial center plane of each annulus of magnetization.
14. A transducer arrangement as claimed in claim 13 wherein there are two magnetic field sensors associated with each annulus of magnetization, the axis of maximum response of each of which sensors is in an axial direction and the two sensors are axially located to one and the other side of the axial center plane of the associated annulus of magnetization.
15. A transducer arrangement comprising a magnetic transducer element as claimed in claim 5 wherein said magnetic transducer element further comprises at least one magnetic field sensor oriented to respond to an axial field component and axially located to one side of the axial center plane of each annulus of magnetization.
16. A transducer arrangement as claimed in claim 15 wherein said magnetic transducer element further comprises at least one magnetic field sensor oriented to respond to an axial field component and axially located to the other side of the axial center plane of each annulus.
17. A transducer arrangement comprising a magnetic transducer element as claimed in claim 6 wherein said magnetic transducer element further comprises at least one magnetic field sensor oriented to respond to a radial field component and axially located at or in the vicinity of the axial center plane of each annulus of magnetization.
18. A magnetic transducer system comprising:
a magnetic transducer element in the form of a member of magnetizable material having an axis about which it is rotatable;
wherein said member is a portion of a shaft, and
said member being magnetized to have a first and second annulus of axially-directed stored magnetization about said axis extending inwardly from an external surface of said member, the first and second annuli being axially spaced and, preferably, each annulus of magnetization emanating no significant component of circumferential (tangential) magnetic flux externally of said surface when the member is subject to torque applied to said member about said axis, and each annulus emanating a magnetic field the distribution of a component of which in the axial direction exhibits a magnetic field profile which shifts in the axial direction as a function of torque applied to said member about said axis;
said first annulus exhibiting a magnetic field profile of said component which shifts in the opposite direction to the shift of the magnetic field profile of said component exhibited by said second annulus in response to a given torque applied about said axis; and
a sensor system comprising respective sensor assemblies responsive to the magnetic field profile exhibited by the first and second annulus respectively and means for combining the responses of said sensor assemblies to provide an output signal representing a torque applied to the shaft or an axial displacement of the shaft or respective signals representing the aforementioned torque and axial displacement.
19. A magnetic transducer system as claimed in claim 18 in which said component of the magnetic field emanated by each annulus is an axially-directed component the magnetic field profile of which shifts in the axial direction as a function of torque over at least a portion of the emanated magnetic field.
20. A magnetic transducer system as claimed in claim 18 in which said component of the magnetic field emanated by each annulus is a radial component the magnetic profile of which shifts in the axial direction as a function of torque over at least a portion of the emanated magnetic field.
21. A magnetic transducer system as claimed in claim 18 in which said first annulus of magnetization is created by relative rotation in one direction of said member with respect to means for magnetizing the member and said second annulus of magnetization is created by relative rotation in a direction opposite to said one direction of said member with respect to means for magnetizing the member.
22. A transducer arrangement comprising:
a magnetic transducer element which comprises:
a member of magnetizable material having an axis about which it is rotatable or capable of flexing;
wherein said member is a portion of a shaft, and
wherein said member being magnetized to have an annulus of axially-directed stored magnetization about said axis extending inwardly from an external surface of said member, and said annulus of magnetization emanating no significant component of circumferential (tangential) magnetic flux externally of said surface when the member is subject to torque applied to said member about said axis andor to a force applied to cause said member to flex about said axis, said annulus emanating a magnetic field having a distribution in the direction of said axis, the magnetic field profile of the axial component of which distribution shifts in the axial direction over at least a portion of the distribution of the emanated magnetic field in the axial direction as a function of the torque or the force applied; and at least one magnetic field sensor located adjacent said annulus of magnetisation to sense the field emanated by said element,
wherein the at least one sensor is located axially at a point (sweet spot) at which the magnetic field profile exhibits least variation as a function of the rotational angle of said member.
23. A transducer arrangement as claimed in claim 22 in which there is at least one sensor located at each of a pair of such points (sweet spots) on opposite sides of the centerline of the annulus of magnetization.
24. A transducer arrangement as claimed in claim 22 in which said at least one magnetic field sensor has a direction of minimum response in the circumferential or tangential direction.
25. A transducer arrangement as claimed in claim 22 in which said at least one magnetic field sensor has an axis of maximum response which lies in the axial direction.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A plasma processing systems comprising:
(a) a processing chamber body forming a cavity;
(b) a target disposed in the cavity;
(c) a substrate support member disposed in the cavity;
(d) a coil disposed adjacent the processing region;
(e) at least two current return plates disposed in the cavity; and
(f) a phase shift power source comprising a signal generator electrically coupled to the support member and the at least two current return plates.
2. The system of claim 1, wherein the phase shift power source further comprises a phase modulator; and further comprising a phase shift device electrically coupled between the phase modulator and the at least two current return plates.
3. The system of claim 1, wherein the phase shift power source is configured to phase shift a reference signal output from the signal generator by about 0 degrees to about 360 degrees.
4. The system of claim 1, further comprising a phase shift device disposed between the phase shift power source and the at least two current return plates.
5. The system of claim 4, wherein the phase shift device comprises a phase shifted output for each of the at least two current return plates.
6. The system of claim 1, wherein the phase shift power source comprises a phase modulator electrically coupled to the signal generator.
7. The system of claim 6, further comprising:
a power splitter electrically connected to the signal generator; the power splitter comprising a first output to the support member and a second output to the phase modulator.
8. The system of claim 7, further comprising a first amplifier electrically connected to the first output and a second amplifier electrically connected to the second output; wherein the first amplifier is electrically connected to the support member and the second amplifier is electrically connected to the at least two current return plates.
9. The system of claim 8, wherein the first and the second amplifiers are connected to a common and isolated ground.
10. The system of claim 8, further comprising a phase shift device electrically connected between the second amplifier and the at least two current return plates.
11. The system of claim 7, further comprising:
a phase shift device electrically connected between the phase modulator and the at least two current return plates;
an annular chamber shield disposed in the cavity and selectively electrically coupled to the phase modulator.
12. The system of claim 11, wherein the annular chamber shield is disposed between the processing chamber body and the at least two current return plates.
13. The system of claim 11, further comprising a first switch disposed to selectively couple the annular chamber shield and the phase shift power source.
14. The system of claim 13, further comprising:
a phase shift device electrically coupled between the phase modulator and the at least two current return plates; and
a second switch disposed to selectively couple the phase shift power source and the phase shift device; wherein the first switch and the second switch are alternatively open.
15. A method for operating a deposition vacuum chamber comprising a target at one end of the vacuum chamber, a substrate support member on another end of the vacuum chamber and at least two current return plates disposed between the ends of the vacuum chamber, the method comprising:
(a) supplying a first signal to the target;
(b) supplying a reference signal to the substrate support member; and
(c) modulating a resultant electric field between the substrate support member and the at least two current return plates by changing a phase relationship between the reference signal and a phase shifted signal on the at least two current return plates.
16. The method of claim 15, further comprising generating the reference signal and the phase shifted signal from a common signal generator.
17. The method of claim 15, wherein modulating the resultant electric field comprises rotating the electric field 360 about the substrate support member.
18. The method of claim 15, wherein modulating the resultant electric field comprises varying the strength of the electric field.
19. The method of claim 15, further comprising providing a coil signal to an inductive coil disposed between the ends of the vacuum chamber.
20. The method of claim 15, further comprising modulating the reference signal.
21. The method of claim 15, wherein the reference signal and the phase shifted signal are RF signals.
22. A plasma processing system, comprising:
(a) a processing chamber body forming a cavity;
(b) a substrate support member disposed in the cavity;
(c) at least two current return plates disposed in the cavity; and
(d) a phase shift power source comprising (i) a signal generator electrically coupled to the support member and the at least two current return plates and (ii) a phase modulator electrically coupled between the signal generator and the at least two current return plates.
23. The system of claim 22, further comprising an inductive coil disposed in the cavity and wherein the at least two current return plates are disposed between the coil and the processing chamber body.
24. The system of claim 22, wherein the phase modulator is configured to phase shift a reference signal output from the signal generator by about 0 degrees to about 360 degrees.
25. The system of claim 22, wherein the phase shift power source comprises a reference signal output connected to the support member and a phase shifted reference signal output connected to the at least two current return plates.
26. The system of claim 22, further comprising a phase shift device electrically coupled between the phase modulator and the at least two current return plates.
27. The system of claim 26, wherein the phase shift device comprises a phase shifted output for each of the at least two current return plates.
28. The system of claim 22, further comprising a power splitter electrically connected to the signal generator; the power splitter comprising a first output to the support member and a second output to the phase modulator.
29. The system of claim 28, further comprising a first amplifier electrically connected to the first output and a second amplifier electrically connected to the second output; wherein the first amplifier is electrically connected to the support member and the second amplifier is electrically connected to the at least two current return plates.
30. The system of claim 29, wherein the first and the second amplifiers are connected to a common and isolated ground.
31. The system of claim 29, further comprising a phase shift device electrically connected between the second amplifier and the at least two current return plates.
32. The system of claim 22, further comprising:
a phase shift device electrically connected between the phase modulator and the at least two current return plates;
an annular chamber shield disposed in the cavity and selectively electrically coupled to the phase modulator.
33. The system of claim 32, wherein the annular chamber shield is disposed between the processing chamber body and the at least two current return plates.
34. The system of claim 32, further comprising a first switch disposed to selectively couple the annular chamber shield and the phase shift power source.
35. The system of claim 34, further comprising:
a phase shift device electrically coupled between the phase modulator and the at least two current return plates; and
a second switch disposed to selectively couple the phase shift power source and the phase shift device; wherein the first switch and the second switch are alternatively open.