Lithographic apparatus and device manufacturing method

• US 20050007569A1
• Filed: 05/13/2004
• Published: 01/13/2005
• Est. Priority Date: 05/13/2003
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Donders, Sjoerd Nicolaas Lambertus, Baselmans, Johannes Jacobus Matheus, Mulkens, Johannes Catharinus Hubertus, Streefkerk, Bob, Bakker, Levinus Pieter, Loopstra, Erik Roelof, Straaijer, Alexander, Mertens, Jeroen Johannes Sophia Maria, Lof, Joeri, Slaghekke, Bernardus Antonius, Simon, Klaus, Hoogendam, Christiaan Alexander, Derksen, Antonius Theodorus Anna Maria, Van Der Meulen, Frits, Cox, Hendrikus Herman Marie, Houkes, Martijn, Van Nunen, Gerardus Petrus Matthijs, Van Der Toorn, Jan-Gerard Cornelis
• Granted Patent: US 7,352,434 B2
• Time in Patent Office: Days
• US Class Current: 355/30
• CPC Class Codes: G03F 7/70341 Details of immersion lithography aspects, e.g. exposure media or control of immersion liquid supply chemical composition of immersion liquids G03F7/2041
• CPC Class Codes: G03F 7/70425 Imaging strategies, e.g. for increasing throughput or resolution, printing product fields larger than the image field or compensating lithography- or non-lithography errors, e.g. proximity correction, mix-and-match, stitching or double patterning
• CPC Class Codes: G03F 7/70525 Controlling normal operating mode, e.g. matching different apparatus, remote control or prediction of failure
• CPC Class Codes: G03F 7/709 Vibration, e.g. vibration detection, compensation, suppression or isolation

Abstract

In a lithographic apparatus, a localized area of the substrate surface under a projection system is immersed in liquid. The height of a liquid supply system above the surface of the substrate can be varied using actuators. A control system uses feedforward or feedback control with input of the surface height of the substrate to maintain the liquid supply system at a predetermined height above the surface of the substrate.

Claims

1. A lithographic projection apparatus, comprising:

a radiation system configured to provide a beam of radiation;

a support configured to support a patterning device, the patterning device configured to pattern the beam according to a desired pattern;

a substrate table configured to hold a substrate;

a projection system configured to project the patterned beam onto a target portion of the substrate and having an optical axis; and

a liquid supply system configured to provide an immersion liquid on the substrate in a space between the projection system and the substrate, wherein at least part of the liquid supply system is free to move in the direction of the optical axis and/or rotate about at least one axis perpendicular to the optical axis.

2. An apparatus according to claim 1, further comprising:

an actuator configured to adjust at least one of the height and tilt of at least part of the liquid supply system relative to the substrate.

3. An apparatus according to claim 2, further comprising:

a control system configured to control the actuator to maintain a predetermined height of at least part of the liquid supply system above the substrate.

4. An apparatus according to claim 3, further comprising:

at least one sensor configured to measure a height of at least part of the liquid supply system above the surface of the substrate, wherein the control system uses a feedback control method with input from the at least one sensor.

5. An apparatus according to claim 3, further comprising:

a measurement system configured to measure a surface height of the substrate prior to the entry of the substrate into the projection system and to store the measured height in a storage device, wherein the control system uses feedforward control with input of the measured height from the storage device.

6. An apparatus according to claim 3, further comprising:

at least one sensor configured to measure a height of the substrate in an exposure position, wherein the control system uses a feedforward control method with input of the height of the substrate in an exposure position.

7. An apparatus according to claim 2, wherein, in a non-actuated state, the actuator positions the liquid supply system to a maximum setting away from the surface of the substrate in the direction of the optical axis of the projection system.

8. An apparatus according to claim 2, wherein the actuator is connected between the liquid supply system and at least one of a base frame that supports the substrate table and a reference frame that supports the projection system.

9. An apparatus according to claim 8, wherein at least one of supporting members and at least one second actuator are connected between the liquid supply system and at least one of the base frame and the reference frame to keep the liquid supply system substantially stationary relative to the projection system in a plane perpendicular to the optical axis.

10. An apparatus according to claim 2, wherein the actuator is part of the liquid supply system, the actuatorn comprising:

a seal extending along at least part of a boundary of the space between a final element of the projection system and the substrate table; and

a gas seal configured to form a gas seal between the seal and the surface of the substrate;

wherein the pressure in the gas seal is variable to adjust at least one of the height and tilt of the liquid supply system relative to the substrate.

11. An apparatus according to claim 10, further comprising:

at least one sensor configured to measure a position of an edge of the liquid relative to the gas seal and a controller configured to vary the pressure in the gas seal to influence the position of the edge of the liquid.

12. An apparatus according to claim 11, wherein the controller operates in a feedforward manner, based on the distance between the seal and the substrate.

13. An apparatus according to claim 3, wherein the predetermined height is approximately 10 μ

m to 1000 μ

m

14. An apparatus according to claim 1, further comprising:

a dummy disk configured to be positioned under the liquid supply system during a substrate exchange, wherein the dummy disk is attachable to the at least part of the liquid supply system, and the at least part of the liquid supply system is movable away from the substrate with the dummy disk attached during substrate swap.

15. An apparatus according to claim 1, wherein the part of the liquid supply system is braced away from the substrate table by a non-electrical, mechanical device or a magnetic device.

16. An apparatus according to claim 1, further comprising:

a safety controller configured to monitor at least one of relative positions and velocity of the part of the liquid supply system and the substrate table.

17. An apparatus according to claim 16, wherein the safety controller is configured to control movement of at least one of the part of the liquid supply system and the substrate table in the event of a collision risk being determined from the monitoring thereby to prevent the collision.

18. An apparatus according to claim 1, further comprising:

a positional controller configured to generate control signals to position the part of the liquid supply system in the direction of the optical axis.

19. An apparatus according to claim 18, wherein the positional controller is also configured to generate control signals to position the substrate table in the direction of the optical axis.

20. An apparatus according to claim 19, further comprising:

a feedforward compensator configured to compensate the control signals to position the substrate table based on the control signals to positionthe part of the liquid supply system.

21. An apparatus according to claim 20, wherein the feedforward compensator is configured to compensate for closed loop characteristics of the part of the liquid supply system.

22. An apparatus according to claim 19, further comprising:

a damping and stiffness compensator configured to compensate the control signals to position the part of the liquid supply system to mitigate for the damping coefficient and stiffness of immersion liquid between the liquid supply system and the substrate.

23. An apparatus according to claim 1, wherein at least part of the liquid supply system is free to rotate around axes orthogonal to the optical axis.

24. A device manufacturing method, comprising:

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

projecting a patterned beam of radiation onto a target portion of the layer of radiation-sensitive material using a projection system,

providing a liquid on the substrate to fill a space between the substrate and the projection system; and

allowing a system which provides the liquid to move freely in the direction of the optical axis of the projection system.