Projection system for a lithographic apparatus

• US 7,426,076 B2
• Filed: 12/23/2004
• Issued: 09/16/2008
• Est. Priority Date: 12/23/2004
• Status: Expired due to Fees

• Current Assignee: ASML Holding NV, ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Holding NV, ASML Netherlands BV (ASML Holding NV)
• Inventors: Gui, Cheng-Qun, De Jager, Pieter Willem Herman, Harned, Robert D., Harned, Nora-Jean
• Primary Examiner(s): Pritchett; Joshua L
• Application Number:
  US11/019,672
• Publication Number:
  US 20060139745A1
• Time in Patent Office: 1,363 Days
• Field of Search: 359/366
• US Class Current: 359/366
• CPC Class Codes: G02B 17/002 Arrays of reflective systems
• CPC Class Codes: G02B 17/008 Systems specially adapted to form image relays or chained systems
• CPC Class Codes: G02B 17/0812 off-axis or unobscured systems in which all of the mirrors share a common axis of rotational symmetry
• CPC Class Codes: G03F 7/70233 Optical aspects of catoptric systems, i.e. comprising only reflective elements, e.g. extreme ultraviolet [EUV] projection systems
• CPC Class Codes: G03F 7/70275 Multiple projection paths, e.g. array of projection systems, microlens projection systems or tandem projection systems

Abstract

A projection system for a lithographic apparatus having a plurality of mirror imaging systems. In an embodiment, the mirror imaging systems are arranged in two rows with each row being perpendicular to a scanning direction of the projection system. Each mirror imaging systems has an associated imaging field. The mirror imaging systems are arranged in a manner that precludes gaps between adjacent imaging fields in the scanning direction. Each mirror imaging system includes a concave mirror and a convex mirror arranged concentrically with the concave mirror. The concave mirrors have a first mirror portion and a second mirror portion that are independently movable. In one embodiment, each of the mirror imaging systems has an associated phase, and the mirror imaging systems in one row are positioned 180 degrees out of phase with the mirror imaging systems in the other row.

Claims

1. A projection system for projecting radiation onto a substrate, comprising:

a plurality of mirror imaging systems each comprising at least a concave mirror and a convex mirror, wherein each mirror imaging system is arranged to direct radiation onto an associated imaging field at the substrate, wherein each concave mirror comprises a separate first mirror portion and a second mirror portion, the first and second mirror portions being independently moveable;

a first flat mirror arranged to direct incident light towards the concave mirror; and

a second flat mirror arranged to reflect light from a patterning device to the first flat mirror;

wherein the first flat mirror and the second flat mirror are arranged so as to receive an image from the patterning device and to reflect the image to the concave mirror so that the orientation of the image at the substrate is the same as the orientation of a corresponding portion of the patterning device producing the image.

2. The projection system of claim 1, wherein each convex mirror is arranged concentrically with its respective concave mirror.

3. The projection system of claim 1, wherein the concave mirrors of each mirror imaging system are shaped to allow the mirror imaging systems to be arranged in a manner that precludes gaps between adjacent imaging fields in a scanning direction.

4. The projection system of claim 1, wherein the mirror imaging systems are arranged in a first row and a second row with each row being perpendicular to a scanning direction.

5. The projection system of claim 4, wherein the second row of the mirror imaging systems is a mirror image of the first row of the mirror imaging systems such that the first and second row establish imaging fields on the opposite sides of a plane.

6. The projection system of claim 4, wherein the mirror imaging systems are arranged in a manner that precludes gaps between adjacent imaging fields in a scanning direction.

7. The projection system of claim 1, wherein the final image formed by all of the mirror imaging systems at the substrate corresponds with the patterning device as a whole.

8. The projection system of claim 1, further comprising a third flat mirror arranged to reflect light from the concave mirror to a substrate.

9. A lithographic apparatus, comprising:

an illumination system that supplies a beam of radiation;

a patterning device that imparts the beam of radiation with a pattern;

a substrate table that supports a substrate;

a projection system that projects the patterned beam of radiation onto a target portion of the substrate, the projection system comprises a plurality of mirror imaging systems, each mirror imaging system comprising at least a concave mirror and a convex mirror arranged to direct incident radiation onto an associated imaging field at the substrate, wherein each concave mirror comprises a separate first mirror portion and a second mirror portion, the first and second mirror portions being independently moveable;

a first flat mirror arranged to direct incident light towards the concave mirror; and

a second flat mirror arranged to reflect light from a patterning device to the first flat mirror;

wherein the first flat mirror and the second flat mirror are arranged so as to receive an image from the patterning device and to reflect the image to the concave mirror so that the orientation of the image at the substrate is the same as the orientation of a corresponding portion of the patterning device producing the image.

10. The lithographic apparatus of claim 9, where the patterning device comprises a mask.

11. The lithographic apparatus of claim 9, where the patterning device comprises an array of individually controllable light modulating elements.

12. A device manufacturing method, comprising:

(1) emitting a beam of radiation;

(2) imparting the beam of radiation with a pattern; and

(3) projecting the patterned beam of radiation onto a substrate, wherein the patterned beam of radiation is projected onto the substrate using a projection system comprises a plurality of mirror imaging systems, each mirror imaging system comprising at least a concave mirror and a convex mirror arranged to direct radiation onto an associated imaging field at the substrate, wherein each concave mirror comprises a separate first mirror portion and a second mirror portion, the first and second mirror portions being independently moveable;

a first flat mirror arranged to direct incident light towards the concave mirror; and

a second flat mirror arranged to reflect light from a patterning device to the first flat mirror;

wherein the first flat mirror and the second flat mirror are arranged so as to receive an image from the patterning device and to reflect the image to the concave mirror in a way that the orientation of the image at the substrate is the same as the orientation of a corresponding portion of the patterning device producing the image.

13. A flat panel display comprising a substrate produced using the method of claim 12.