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The invention relates to a system for magnetically shielding a charged particle lithography apparatus. The system comprises a first chamber, a second chamber and a set of two coils. The first chamber has walls comprising a magnetic shielding material, and, at least partially, encloses the charged pa

The invention relates to a system for magnetically shielding a charged particle lithography apparatus. The system comprises a first chamber, a second chamber and a set of two coils. The first chamber has walls comprising a magnetic shielding material, and, at least partially, encloses the charged particle lithography apparatus. The second chamber also has walls comprising a magnetic shielding material, and encloses the first chamber. The set of two coils is disposed in the second chamber on opposing sides of the first chamber. The two coils have a common axis.

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1. A system for magnetically shielding a charged particle lithography apparatus, the system comprising: a first chamber having walls comprising a magnetic shielding material, the first chamber enclosing, at least partially, the charged particle lithography apparatus;a second chamber forming part of

1. A system for magnetically shielding a charged particle lithography apparatus, the system comprising: a first chamber having walls comprising a magnetic shielding material, the first chamber enclosing, at least partially, the charged particle lithography apparatus;a second chamber forming part of a vacuum chamber and having walls comprising a magnetic shielding material, the second chamber enclosing the first chamber;a moveable stage element arranged for supporting a substrate support structure, and positioned outside the first chamber and inside the second chamber;a set of two coils disposed in the second chamber outside of the first chamber and on opposing sides of the first chamber and the moveable stage element, the two coils having a common axis, andat least one magnetic field sensor positioned outside the first chamber and inside the second chamber, for measuring the magnetic field within the second chamber,wherein the first chamber is provided with an opening at a side facing the moveable stage element, for allowing charged particle radiation originating from the lithography apparatus to be exposed on a substrate provided on the substrate support structure, and wherein the at least one magnetic field sensor is positioned between the opening and the moveable stage element,wherein the system comprises a control system configured for controlling the currents through the coils based on information provided by the at least one magnetic field sensor, so as to nullify the magnetic field measured between the opening and the moveable stage element during operation,wherein the distance between a coil and the closest wall of the second chamber measured along a direction substantially parallel to the common axis is smaller than such distance between said coil and the closest wall of the first chamber. 2. The system of claim 1, wherein the second chamber encloses: a first set of two coils disposed on opposing sides of the first chamber, the two coils of the first set having a common axis in a first direction;a second set of coils disposed on opposing sides of the first chamber, the two coils of the second set having a common axis in a second direction substantially perpendicular to the first direction;a third set of coils disposed on opposing sides of the first chamber, the two coils of the third set having a common axis in a third direction substantially perpendicular to the first direction and the second direction. 3. The system of claim 1, wherein the distance between the coil and the closest wall of the first chamber is at least twice the distance between said coil and the closest wall of the second chamber. 4. The system of claim 1, wherein the coils are disposed in close proximity of the walls of the second chamber. 5. The system of claim 1, wherein all walls of the first chamber are disposed closer to the charged particle lithography apparatus than to at least one wall of the second chamber. 6. The system of claim 5, wherein all walls of the first chamber are disposed closer to the charged particle lithography apparatus than to any wall of the second chamber. 7. The system of claim 1, wherein the magnetic shielding material includes a material with a relative magnetic permeability greater than 300,000. 8. The system of claim 7, wherein the material is a mu metal. 9. The system of claim 1, wherein the first chamber is provided with a degaussing arrangement. 10. The system of claim 9, wherein the degaussing arrangement comprises one or more degauss coils. 11. The system of claim 1, wherein the second chamber is provided with a degaussing arrangement. 12. The system of claim 11, wherein the degaussing arrangement comprises one or more degauss coils. 13. The system of claim 1, wherein the first chamber has a cubical, cylindrical or box-like shape. 14. The system of claim 1, further comprising at least one magnetic field sensor for measuring the magnetic field within the first chamber. 15. The system of claim 14, further comprising a control system for controlling the currents through the coils based on information provided by the at least one magnetic field sensor. 16. The system of claim 1, wherein the charged particle lithography system comprises: a charged particle source for generating one or more charged particle beams;a moveable device for supporting the target; anda patterning device for enabling the transfer of the one or more beams onto the target surface in accordance with the pattern. 17. The system of claim 16, wherein the first chamber encloses the charged particle source and the patterning device, wherein the moveable device is located outside the first chamber, and wherein the first chamber is provided with the opening at a side facing the moveable device. 18. The system of claim 1, wherein at least one of the first chamber and the second chamber is provided with a removably attachable door, wherein the door is attachable by means of one or more connection bars. 19. The system of claim 18, wherein the one or more connection bars are hollow. 20. The system of claim 18, wherein the one or more connection bars include at least one inner bar for attachment to the door at the inside of the respective chamber and at least one outer bar for attachment to the door at the outside of the respective chamber, wherein the at least one inner bar and the at least one outer bar are provided with a plurality of mutually aligned holes at opposing sides thereof, and wherein the at least one inner bar and the at least one outer bar are connected to each other by connection of the at least one outer bar to the at least one inner bar using a connection element extending though two mutually aligned holes in the outer bar and through corresponding mutually aligned holes in the inner bar. 21. The system of claim 20 wherein the number of mutually aligned holes in the inner bar is greater than the number of mutually aligned holes in the outer bar. 22. The system of claim 20, wherein the connection element is a bolt, and the connection is fixated using a nut. 23. The system of claim 18, wherein one or more spring elements are provided between the bars and the door. 24. A method for magnetically shielding in a charged particle lithography apparatus, the method comprising: providing the charged particle lithography apparatus enclosed in a first chamber of a system for magnetically shielding the charged particle lithography apparatus according to claim 1;providing a substrate on a substrate support structure on a moveable stage element arranged in a second chamber of the system;exposing the substrate with charged particle radiation originating from the lithography apparatus via an opening in the first chamber, andmeasuring the magnetic field within the second chamber with at least one magnetic field sensor positioned outside the first chamber and inside the second chamber, between the opening and the moveable stage element. 25. The method of claim 24, wherein the step of exposing the substrate provided on the substrate support structure comprises: placing the substrate support structure at a position below the opening in the first chamber. 26. The method of claim 24, wherein the step of measuring the magnetic field within the second chamber comprises: adjusting compensation currents in the coils until the magnetic field measured with the at least one magnetic field sensor substantially equals zero, andmaintaining the compensation currents in the coils during exposure of the target by the charged particle lithography apparatus. 27. The method of claim 25, wherein the step of maintaining the compensation currents in the coils during exposure of the target comprises: measuring and compensating the magnetic field during subsequent movement of the stage element supporting the target. 28. A system for magnetically shielding a charged particle lithography apparatus, the system comprising: a first chamber having walls comprising a magnetic shielding material, the first chamber enclosing, at least partially, the charged particle lithography apparatus;a second chamber forming part of a vacuum chamber and having walls comprising a magnetic shielding material, the second chamber enclosing the first chamber;a moveable stage element arranged for supporting a substrate support structure, and positioned outside the first chamber and inside the second chamber;wherein the first chamber is provided with an opening at a side facing the moveable stage element, for allowing charged particle radiation originating from the lithography apparatus to be exposed on a substrate provided on the substrate support structure;wherein the first chamber has a cubical or box-like shape, and wherein the first chamber is provided with a degaussing arrangement, comprising at least one degauss coil that forms a path along three consecutive edges on the inside of the first chamber walls and back along the three consecutive edges on the outside of the first chamber walls, andwherein the distance between a degauss coil and the closest wall of the first chamber measured along a direction substantially perpendicular to the path is smaller than such distance between said degauss coil and the closest wall of the second chamber. 29. The system according to claim 28, wherein the second chamber has a cubical or box-like shape, and wherein the second chamber is provided with a further degaussing arrangement comprising at least one further degauss coil that traces a further path along three consecutive edges on the inside of the second chamber walls, and returning along the three consecutive edges on the outside of the second chamber walls, wherein the distance between a further degauss coil and the closest wall of the second chamber measured along a direction substantially perpendicular to the further path is smaller than such distance between said further degauss coil and the closest wall of the first chamber.