Safety mechanism for a lithographic patterning device

• US 20050083499A1
• Filed: 07/20/2004
• Published: 04/21/2005
• Est. Priority Date: 07/22/2003
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Van De Ven, Bastiaan Lambertus Wilhelmus Marinus, Heerens, Gert-Jan
• Granted Patent: US 7,466,397 B2
• Time in Patent Office: Days
• US Class Current: 355/53
• CPC Class Codes: G03F 7/707 Chucks, e.g. chucking or un-chucking operations or structural details
• CPC Class Codes: G03F 7/70716 Stages
• CPC Class Codes: G03F 7/70741 Handling masks outside exposure position, e.g. reticle libraries
• CPC Class Codes: G03F 7/70783 Handling stress or warp of chucks, masks or workpieces, e.g. to compensate for imaging errors or considerations related to warpage of masks or workpieces due to their own weight
• CPC Class Codes: G03F 7/70825 Mounting of individual elements, e.g. mounts, holders or supports workpiece or mask holders G03F7/707
• CPC Class Codes: G03F 7/709 Vibration, e.g. vibration detection, compensation, suppression or isolation

Abstract

A lithographic apparatus equipped with a patterning device safety mechanism, is presented herein. In one embodiment, the apparatus comprises an illumination system for providing a beam of radiation, a support structure for supporting a patterning device that serves to impart the beam of radiation with a pattern in its cross-section, a substrate holder for holding a substrate having a plurality of target portions, a projection system for projecting the patterned beam onto the substrate target portions, a connector for securing the patterning device relative to the support structure, and a safety mechanism configured to reduce uncontrolled displacement of the patterning device in case of failure of the connector.

Claims

1. A lithographic apparatus comprising:

a substrate holder configured to hold a substrate;

an illuminator configured to condition a beam of radiation;

a support structure configured to support a patterning device that imparts a desired pattern onto the beam of radiation;

a projection system that projects the patterned beam to a target portion of the substrate;

a connector that secures said patterning device relative to said support structure; and

a safety mechanism configured to contain displacement of said patterning device in case of failure of said connector.

2. The lithographic apparatus of claim 1, further comprising:

a positioning system configured to position said patterning device relative to said support structure, and

a lithographic operational cycle, comprising;

(a) a projection phase, in which said patterning device is secured to said support structure by said connector while said patterned beam is projected onto a target portion of the substrate, and

(b) an exchange phase, in which said patterning device is exchanged, said positioning system positions said patterning device relative to said support structure, and at least a part of said positioning system is withdrawn after said patterning device has been positioned,

wherein said safety mechanism is configured to contain said patterning device in case of failure of said connector at least during the projection phase.

3. The lithographic apparatus of claim 2, wherein said safety mechanism comprises:

at least one x-directed stopping structure and at least one y-directed stopping structure, said x-directed stopping structure and said y-directed stopping structure configured to contain said patterning device relative to the support structure in the xy plane of said patterning device,

at least one z-directed stopping structure configured to contain said patterning device relative to said support structure in a direction out of the xy plane of said patterning device,

wherein at least one of said x-directed stopping structure, y-directed stopping structure, z-directed stopping structure are moveable to allow movement of said patterning device during the exchange phase.

4. The lithographic apparatus of claim 3, wherein said safety mechanism comprises at least three x-directed stopping structures, at least three y-directed stopping structures, and at least three z-directed stopping structures.

5. The lithographic apparatus of claim 3, wherein the x-directed stopping structure, the y-directed stopping structure, and the z-directed stopping structure are operated by said positioning system.

6. The lithographic apparatus of claim 3, wherein said x-directed stopping structure, the y-directed stopping structure, and the z-directed stopping structure are operated by dedicated actuators.

7. The lithographic apparatus of claim 3, wherein the distance between said x-directed stopping structure, y-directed stopping structure, and z-directed stopping structure and said patterning device when the patterning device occupies its nominal position relative to said support structure is about 1 mm to about 3 mm.

8. The lithographic apparatus of claim 3, wherein said x-directed stopping structure and y-directed stopping structure are attached to said support structure.

9. The lithographic apparatus of claim 3, wherein said safety mechanism comprises at least an integrated xy-directed stopping structure.

10. The lithographic apparatus of claim 2:

wherein, during the exchange phase, said positioning system performs positioning movements to position said patterning device relative to said support structure including the withdrawal of at least a part of said positioning system after said patterning device has been positioned,

wherein said safety mechanism is equipped with a safety mode and an inactive mode such that said safety mechanism contains said patterning device in case of failure of the connector in the safety mode, and

wherein, during the exchange phase, said safety mechanism is activated based on one or more positioning movements of said positioning system.

11. The lithographic apparatus of claim 10, wherein said safety mechanism comprises a flexible element and a holding element, the flexible element being attached to at least one of said support structure and said projection system, and the holding element being attached to the flexible element.

12. The lithographic apparatus of claim 11, wherein the flexible element is a leaf spring.

13. The lithographic apparatus of claim 11, wherein the flexible element is a spring mounted pin.

14. The lithographic apparatus of claim 10, wherein said positioning system comprises a reticle carrier that is configured to operate said safety mechanism.

15. The lithographic apparatus of claim 10, wherein a part of said positioning system that operates said safety mechanism comprises an interface adapted to engage said safety mechanism.

16. The lithographic apparatus of claim 11, wherein said safety mechanism comprises three flexible elements, each being provided with a holding element.

17. A device manufacturing method, comprising:

providing a substrate that is at least partially covered by a layer of radiation-sensitive material;

conditioning a beam of radiation;

applying a patterning device to configure the conditioned beam of radiation with a desired pattern in its cross-section;

securing said patterning device to a support structure using a connector;

containing said patterning device by safety mechanism in case of failure of said connector; and

projecting the patterned beam of radiation onto a target portion of the substrate.

18. The device manufacturing method of claim 17, further comprising:

positioning said patterning device relative to said support structure via a positioning system, and

providing a lithographic operational cycle, comprising;

(a) a projection phase, in which said patterning device is secured to said support structure by said connector while said patterned beam is projected onto a target portion of the substrate, and

(b) an exchange phase, in which said patterning device is exchanged, said positioning system positions said patterning device relative to said support structure, and at least a part of said positioning system is withdrawn after said patterning device has been positioned,

wherein said safety mechanism is configured to contain said patterning device in case of failure of said connector at least during the projection phase.

19. The device manufacturing method of claim 18, further including:

providing said safety mechanism with at least one x-directed stopping structure and at least one y-directed stopping structure, said x-directed stopping structure and said y-directed stopping structure configured to contain said patterning device relative to the support structure in the xy plane of said patterning device,

providing said safety mechanism with at least one z-directed stopping structure, said z-directed stopping structure configured to contain said patterning device relative to said support structure in a direction out of the xy plane of said patterning device,

wherein at least one of said x-directed stopping structure, y-directed stopping structure, z-directed stopping structure are moveable to allow movement of said patterning device during the exchange phase.

20. The device manufacturing method of claim 19, further comprising:

providing said safety mechanism with at least three x-directed stopping structures, at least three y-directed stopping structures, and at least three z-directed stopping structures.

21. The device manufacturing method of claim 19, further comprising:

operating the x-directed stopping structure, y-directed stopping structure, and z-directed stopping structure by said positioning system.

22. The device manufacturing method of claim 19, further comprising:

operating the x-directed stopping structure, y-directed stopping structure, and z-directed stopping structure by dedicated actuators.

23. The device manufacturing method of claim 19, further comprising:

arranging x-directed stopping structure, y-directed stopping structure, and z-directed stopping structure so that the distance between said x-directed stopping structure, y-directed stopping structure, and z-directed stopping structure and said patterning device when the patterning device occupies its nominal position relative to said support structure is about 1 to about 3 mm.

24. The device manufacturing method of claim 19, further comprising:

attaching said x-directed stopping structure and y-directed stopping structure to said support structure.

25. The device manufacturing method of claim 19, further comprising:

providing said safety mechanism with at least an integrated xy-directed stopping structure.

26. The device manufacturing method of claim 18, further comprising:

performing, during the exchange phase, positioning movements by said positioning mechanism, including the withdrawal of at least a part of said positioning system after said patterning device has been positioned,

equipping said safety mechanism with a safety mode and an inactive mode such that said safety mechanism contains said patterning device in case of failure of the connector in the safety mode, and

activating, during the exchange phase, said safety mechanism based on one or more positioning movements of said positioning system.

27. The device manufacturing method of claim 26, further comprising:

providing said safety mechanism comprises a flexible element and a holding element, the flexible element being attached to at least one of said support structure and said projection system, and the holding element being attached to the flexible element.

28. The device manufacturing method of claim 27, wherein the flexible element comprises a leaf spring.

29. The device manufacturing method of claim 27, wherein the flexible element comprises a spring mounted pin.

30. The device manufacturing method of claim 26, wherein said positioning system comprises a reticle carrier that is configured to operate said safety mechanism.

31. The device manufacturing method of claim 26, wherein the part of said positioning system that operates said safety mechanism comprises an interface adapted to engage said safety mechanism.

32. The device manufacturing method of claim 27, wherein said safety mechanism comprises three flexible elements, each being provided with a holding element.

33. A lithographic apparatus, comprising:

means for holding a substrate having a plurality of target portions;

means for conditioning a beam of radiation;

means for patterning said beam of radiation with a pattern in its cross-section;

means for supporting said patterning means;

means for projecting said patterned beam onto said substrate target portions;

means for securing said patterning device relative to said support means; and

means for containing said patterning means in case of failure of said securing means.

34. A mechanism for containing displacement of a patterning device connected to a movable support structure, comprising:

at least one x-directed stopping structure and at least one y-directed stopping structure, said x-directed stopping structure and said y-directed stopping structure configured to contain said patterning device relative to the support structure along the xy plane of said patterning device; and

at least one z-directed stopping structure configured to contain said patterning device relative to said support structure along a direction out of the xy plane of said patterning device,

wherein at least one of said x-directed stopping structure, y-directed stopping structure, z-directed stopping structure are moveable to allow movement of said patterning device during an exchange of said patterning device.

35. The mechanism of claim 34, wherein the x-directed stopping structure, the y-directed stopping structure, and the z-directed stopping structure are operated by said positioning system.

36. The mechanism of claim 34, wherein said x-directed stopping structure, the y-directed stopping structure, and the z-directed stopping structure are operated by dedicated actuators.

37. The mechanism of claim 34, wherein the distance between said x-directed stopping structure, y-directed stopping structure, and z-directed stopping structure and said patterning device when the patterning device occupies its nominal position relative to said support structure is about 1 mm to about 3 mm.

38. The mechanism of claim 34, wherein said x-directed stopping structure and y-directed stopping structure are attached to said support structure.

39. The mechanism of claim 34, wherein said safety mechanism comprises at least an integrated xy-directed stopping structure.

40. A mechanism for containing displacement of a patterning device connected to a movable support structure, comprising:

a flexible element; and

a holding element attached to the flexible element,

wherein the flexible element is attached to at least one of said movable support structure and a projection system that projects a patterned beam onto a substrate.

41. The mechanism of claim 40, wherein the flexible element is a leaf spring.

42. The mechanism of claim 40, wherein the flexible element is a spring mounted pin.