Patent Number: 
Section: claims

1. An apparatus having a reaction frame that receives reaction forces from a stage comprising: a first reaction frame portion of the reaction frame coupled to ground in a first direction by a ground rod aligned along the longitudinal side of the first reaction frame;  a second reaction frame portion of the reaction frame not coupled directly to ground in the first direction; and  an interconnect rod passing parallel to the plane defined by the first reaction frame portion and second reaction frame portion having a first end and a second end with a damper therebetween, wherein the first end is coupled to the first reaction frame portion and the second end is coupled to the second reaction frame portion and reaction forces in the first direction received by the second reaction frame portion are transferred to ground through the interconnect rod and the first reaction frame portion. 2. The apparatus of  claim 1  further comprising: claim 1 a first drive mechanism having a fixed drive portion and a movable drive portion, the fixed drive portion coupled to the first reaction frame portion and the movable drive portion coupled to the stage that moves in at least the first direction; and  a slidable coupling between the fixed drive portion and the movable drive portion associated with the first drive mechanism that structurally decouples the first reaction frame portion from the stage in at least the first direction. 3. The apparatus in  claim 2  wherein each slidable coupling further includes an air-bearing. claim 2 4. The apparatus of  claim 1  further comprising: claim 1 a second drive mechanism having a fixed drive portion and a movable drive portion, the fixed drive portion coupled to the second reaction frame portion and the movable drive portion coupled to the stage that moves in at least the first direction; and  a slidable coupling between the fixed drive portion and the movable drive portion of the second drive mechanism that structurally decouples the second reaction frame portion from the stage in at least the first direction. 5. The apparatus in  claim 4  wherein each slidable coupling further includes an air-bearing. claim 4 6. The apparatus of  claim 1  further comprising: claim 1 a base;  a first slidable coupling supporting the stage on the base that decouples the stage from the reaction frame in at least the first direction; and  a second slidable coupling supporting the reaction frame on the base that decouples the reaction forces between the stage and the reaction frame. 7. The apparatus in  claim 6  wherein each slidable coupling further includes an air-bearing. claim 6 8. The apparatus in  claim 1  wherein the first direction is along the interconnect rod. claim 1 9. The apparatus in  claim 1  wherein the reaction frame is free to move in X, Y, and Theta Z degrees of freedom with respect to the base. claim 1 10. The apparatus of  claim 1  wherein the ground rod is further alligned along the center-of-gravity associated with the first reaction frame portion. claim 1 11. The apparatus of  claim 1  wherein the damper is implemented using a spring-damper mechanism. claim 1 12. A stage assembly, comprising: a stage guided movably in at least a first direction;  a first reaction frame portion of a reaction frame, the first reaction frame coupled to ground in the first direction by a first ground rod aligned along the longitudinal side of the first reaction frame portion;  a second reaction frame portion of the reaction frame not coupled directly to ground in the first direction; and  an interconnect rod passing parallel to the plane defined by the first reaction frame portion and second reaction frame portion having a first end and a second end with a damper therebetween, wherein the first end is coupled to the first reaction frame portion and the second end is coupled to the second reaction frame portion and reaction forces from the stage moving in the first direction received by the second reaction frame portion are transferred to ground through the interconnect rod and the first reaction frame portion. 13. The stage assembly of  claim 12  wherein the damper is implemented using a spring-damper mechanism. claim 12 14. The stage assembly of  claim 12  further comprising: claim 12 a first drive mechanism having a fixed drive portion and a movable drive portion, the fixed drive portion coupled to the first reaction frame portion and the movable drive portion coupled to the stage that moves in at least the first direction; and  a slidable coupling between the fixed drive portion and the movable drive portion associated with the first drive mechanism that structurally decouples the first reaction frame portion from the stage in at least the first direction. 15. The stage assembly in  claim 14  wherein the reaction frame is free to move in X, Y, and Theta Z degrees of freedom with respect to the base. claim 14 16. The stage assembly of  claim 14  wherein the ground rod is further alligned along the center-of-gravity associated with the first reaction frame. claim 14 17. An exposure system comprising: an illumination system that irradiates radiant energy; and  the stage assembly according to  claim 14 , the stage assembly carrying an object disposed on a path of the radiant energy.  claim 14 18. An object on which an image has been formed by the exposure system of  claim 17 . claim 17 19. The stage assembly of  claim 12  further comprising: claim 12 a second drive mechanism having a fixed drive portion and a movable drive portion, the fixed drive portion coupled to the second reaction frame portion and the movable drive portion coupled to the stage that moves in at least the first direction; and  a slidable coupling between the fixed drive portion and the movable drive portion that structurally decouples the second reaction frame portion from the stage in at least the first direction. 20. The stage assembly in  claim 19  wherein each slidable coupling further includes an air-bearing. claim 19 21. The stage assembly of  claim 12  further comprising: claim 12 a base that the stage is movable thereon;  a first slidable coupling supporting the stage on the base that decouples the stage from the reaction frame in at least the first direction; and  a second slidable coupling supporting the reaction frame on the base that decouples the reaction forces between the stage and the reaction frame. 22. The stage assembly in  claim 21  wherein each slidable coupling further includes an air-bearing. claim 21 23. The stage assembly in  claim 12  wherein the first direction corresponds to the length of the interconnect rod. claim 12 24. The stage assembly in  claim 23  wherein each slidable coupling further includes an air-bearing. claim 23 25. A method of processing reaction forces from a stage, comprising: providing a first reaction frame portion of a reaction frame;  alligning a ground rod attached to ground and coupled along the longitudinal side of the first reaction frame;  providing a second reaction frame portion of the reaction frame; and  interconnecting the first reaction frame portion and second reaction frame portion together with an interconnect rod passing parallel to the plane defined by the first reaction frame portion and second reaction frame portion having a damper along the length of the interconnect rod wherein reaction forces in the first direction received by the second reaction frame portion are transferred to ground through the combination of the interconnect rod, the damper and the first reaction frame portion. 26. The method of  claim 25  further comprising: claim 25 providing a first drive mechanism having a fixed drive portion and a movable drive portion, the fixed drive portion coupled to the first reaction frame portion and the movable drive portion coupled to the stage that moves in at least the first direction; and  structurally decoupling the first reaction frame portion from the stage in at least the first direction using a slidable coupling between the fixed drive portion and the movable drive portion associated with the first drive mechanism. 27. The method of  claim 25  further comprising: claim 25 providing a second drive mechanism having a fixed drive portion and a movable drive portion, the fixed drive portion coupled to the second reaction frame portion and the movable drive portion coupled to the stage that moves in at least the first direction; and  structurally decoupling the first reaction frame portion from the stage in at least the first direction using a slidable coupling between the fixed drive portion and the movable drive portion associated with the second drive mechanism. 28. The method of  claim 25  further comprising: claim 25 providing a base;  structurally decoupling the stage from the base in at least the first direction using a slidable coupling supporting the stage on the base; and  structurally decoupling the reaction forces between the reaction frame and the base in at least the first direction using a slidable coupling supporting the reaction frame on the base. 29. The method of  claim 28  wherein the reaction frame is free to move in X, Y, and Theta Z degrees of freedom with respect to the base. claim 28 30. The method of  claim 25  wherein the ground rod is further alligned along the center-of-gravity associated with the first reaction frame. claim 25 31. The method of  claim 25  wherein the damper is implemented using a spring-damper mechanism. claim 25 32. An apparatus having a reaction frame that receives reaction forces from a stage comprising: a first reaction frame portion of the reaction frame coupled to ground in a first direction by a first ground rod aligned along the longitudinal side of the first reaction frame;  a second reaction frame portion of the reaction frame not coupled directly to ground in the first direction;  an interconnect rod having a first end and a second end alligned with the ground rod, wherein the first end is coupled to the first reaction frame portion and the second end is coupled to the second reaction frame portion and reaction forces in the first direction received by the second reaction frame portion are transferred to ground through the combination of the interconnect rod and the first reaction frame portion. 33. The apparatus of  claim 32  further comprising: claim 32 a first drive mechanism having a fixed drive portion and a movable drive portion, the fixed drive portion coupled to the first reaction frame portion and the movable drive portion coupled to the stage that moves in at least the first direction; and  a slidable coupling between the fixed drive portion and the movable drive portion associated with the first drive mechanism that structurally decouples the first reaction frame portion from the stage in at least the first direction. 34. The apparatus in  claim 33  wherein each slidable coupling further includes an air-bearing. claim 33 35. The apparatus of  claim 32  further comprising: claim 32 a second drive mechanism having a fixed drive portion and a movable drive portion, the fixed drive portion coupled to the second reaction frame portion and the movable drive portion coupled to the stage that moves in at least the first direction; and  a slidable coupling between the fixed drive portion and the movable drive portion associated with the second drive mechanism that structurally decouples the second reaction frame portion from the stage in at least the first direction. 36. The apparatus in  claim 35  wherein each slidable coupling further includes an air-bearing. claim 35 37. The apparatus of  claim 32  further comprising: claim 32 a base;  a first slidable coupling supporting the stage on the base that decouples the stage from the reaction frame in at least the first direction; and  a second sidable coupling supporting the reaction frame on the base that decouples the reaction forces between the stage and the reaction frame. 38. The apparatus in  claim 37  wherein each slidable coupling further includes an air-bearing. claim 37 39. The apparatus in  claim 32  wherein the reaction frame is free to move in X, Y, and Theta Z degrees of freedom with respect to the base. claim 32 40. The apparatus of  claim 32  wherein the ground rod is further alligned along the center-of-gravity of the first reaction frame portion. claim 32 41. A stage assembly, comprising: a stage guided movably in at least a first direction;  a first reaction frame portion of the reaction frame coupled to ground in the first direction by a ground rod aligned along the longitudinal side of the first reaction frame;  a second reaction frame portion of the reaction frame; and  an interconnect rod having a first end and a second end alligned with the ground rod, wherein the first end is coupled to the first reaction frame portion and the second end is coupled to the second reaction frame portion and reaction forces in the first direction received by the second reaction frame portion are transferred to ground through the combination of the interconnect rod and the first reaction frame portion. 42. The stage assembly of  claim 41  further comprising: claim 41 a first drive mechanism having a fixed drive portion and a movable drive portion, the fixed drive portion coupled to the first reaction frame portion and the movable drive portion coupled to the stage that moves in at least the first direction; and  a slidable coupling between the fixed drive portion and the movable drive portion associated with the first drive mechanism that structurally decouples the first reaction frame portion from the stage in at least the first direction. 43. The stage assembly in  claim 42  wherein each slidable coupling further includes an air-bearing. claim 42 44. The stage assembly of  claim 41  further comprising: claim 41 a second drive mechanism having a fixed drive portion and a movable drive portion, the fixed drive portion coupled to the second reaction frame portion and the movable drive portion coupled to the stage that moves in at least the first direction; and  a slidable coupling between the fixed drive portion and the movable drive portion that structurally decouples the second reaction frame portion from the stage in at least the first direction. 45. The stage assembly in  claim 44  wherein each slidable coupling further includes an air-bearing. claim 44 46. The stage assembly of  claim 41  further comprising: claim 41 a base that the stage is movable thereon;  a first slidable coupling supporting the stage on the base that decouples the stage from the reaction frame in at least the first direction; and  a second slidable coupling supporting the reaction frame on the base that decouples the reaction forces between the stage and the reaction frame. 47. The stage assembly in  claim 46  wherein each slidable coupling further includes an air-bearing. claim 46 48. The apparatus in  claim 41  wherein the reaction frame is free to move in X, Y, and Theta Z degrees of freedom with respect to the base. claim 41 49. An object on which an image has been formed by the exposure system of  claim 48 . claim 48 50. The stage assembly of  claim 41  wherein the ground rod is further alligned along the center-of-gravity of the first reaction frame. claim 41 51. An exposure system comprising: an illumination system that irradiates radiant energy; and the stage assembly according to  claim 41 , the stage assembly carrying an object disposed on a path of the radiant energy.  claim 41 52. A method of processing reaction forces from a stage, comprising: providing a first reaction frame portion of a reaction frame;  alligning a ground rod attached to ground and coupled along the longitudinal side of the first reaction frame;  providing a second reaction frame portion of the reaction frame not coupled directly to ground in the first direction; and  interconnecting the first reaction frame portion and second reaction frame portion together with an interconnect rod having a first end and a second end alligned with the ground rod, wherein the first end is coupled to the first reaction frame portion and the second end is coupled to the second reaction frame portion and reaction forces in the first direction received by the second reaction frame portion are transferred to ground through the combination of the interconnect rod and the first reaction frame portion. 53. The method of  claim 52  further comprising: claim 52 providing a first drive mechanism having a fixed drive portion and a movable drive portion, the fixed drive portion coupled to the first reaction frame portion and the movable drive portion coupled to the stage that moves in at least the first direction; and  structurally decoupling the first reaction frame portion from the stage in at least the first direction using a slidable coupling between the fixed drive portion and the movable drive portion associated with the first drive mechanism. 54. The method of  claim 52  further comprising: claim 52 providing a second drive mechanism having a fixed drive portion and a movable drive portion, the fixed drive portion coupled to the second reaction frame portion and the movable drive portion coupled to the stage that moves in at least the first direction; and  structurally decoupling the first reaction frame portion from the stage in at least the first direction using a slidable coupling between the fixed drive portion and the movable drive portion associated with the second drive mechanism. 55. The method of  claim 52  further comprising: claim 52 providing a base;  structurally decoupling the stage from the base in at least the first direction using a third slidable coupling supporting the stage on the base; and  structurally decoupling the reaction forces between the reaction frame and the base in at least the first direction using a fourth slidable coupling supporting the reaction frame on the base. 56. The method of  claim 55  wherein the reaction frame is free to move in X, Y, and Theta Z degrees of freedom with respect to the base. claim 55 57. The method of  claim 52  wherein the ground rod is further alligned along the center-of-gravity of the first reaction frame portion. claim 52