Off-axis catadioptric projection optical system for lithography

• US 7,511,798 B2
• Filed: 07/30/2004
• Issued: 03/31/2009
• Est. Priority Date: 07/30/2004
• Status: Expired due to Fees

• Current Assignee: ASML Holding NV
• Original Assignee: ASML Holding NV
• Inventors: Oskotsky, Mark, Smirnov, Stanislav
• Primary Examiner(s): Fuller; Rodney E
• Application Number:
  US10/902,469
• Publication Number:
  US 20060023191A1
• Time in Patent Office: 1,705 Days
• Field of Search: 355/43, 355/45, 355/51, 355/53, 355/57, 355/60, 355/66, 355/67, 355/77
• US Class Current: 355/66
• 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: G03B 27/54 Lamp housings; Illuminating means
• CPC Class Codes: G03F 7/70225 Optical aspects of catadioptric systems, i.e. comprising reflective and refractive elements

Abstract

An off-axis catadioptric projection optical systems for use in lithography tools for processing modulated light used to form an image on a substrate is provided. In one embodiment the optical system includes an off-axis mirror segment, a fold mirror, a relay, an aperture stop and a refractive lens group. Modulated light is transmitted through the system to form an image on a substrate. In a second embodiment the projection system includes an off-axis mirror segment, an aperture stop and a refractive lens group. In a third embodiment the projection system includes an off-axis mirror segment, a negative refractive lens group, a concave mirror, a relay, an aperture stop, and a refractive lens group. A method to produce a device using a lithographic apparatus including a projection system with an off-axis mirror segment as the first element in a projection optics system is also provided.

Claims

1. A projection system having multiple mirror segments for use in a lithography tool for processing modulated light used to form an image on a substrate, comprising:

an off-axis mirror segment that receives modulated light, wherein an axis of the off-axis mirror segment differs from an axis of the substrate, wherein the off-axis mirror segment is the first mirror segment within the projection system;

an aperture stop that receives the modulated light from said off-axis mirror segment; and

a refractive lens group that focuses the modulated light onto the substrate;

wherein the projection system is configured such that an intermediate real image is not formed between the off-axis mirror segment and the refractive lens group.

2. The projection system of claim 1, further comprising a pattern generating device that provides the modulated light for use in forming the image on the substrate.

3. The projection system of claim 2, wherein said pattern generating device is a spatial light modulator.

4. The projection system of claim 1, wherein said off-axis mirror segment is concave.

5. The projection system of claim 1, wherein said off-axis mirror segment provides field curvature correction.

6. The projection system of claim 1, wherein said substrate is a semiconductor wafer or flat panel display.