Lithographic apparatus and device manufacturing method

• US 7,274,029 B2
• Filed: 12/28/2004
• Issued: 09/25/2007
• Est. Priority Date: 12/28/2004
• Status: Expired due to Fees

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: De Smit, Joannes Theodoor, Lof, Joeri
• Primary Examiner(s): Vanore; David
• Application Number:
  US11/022,923
• Publication Number:
  US 20060138358A1
• Time in Patent Office: 1,001 Days
• Field of Search: None
• US Class Current: 250/492.22
• CPC Class Codes: G03F 7/70258 Projection system adjustments, e.g. adjustments during exposure or alignment during assembly of projection system
• CPC Class Codes: G03F 7/70275 Multiple projection paths, e.g. array of projection systems, microlens projection systems or tandem projection systems
• CPC Class Codes: G03F 7/70291 Addressable masks, e.g. spatial light modulators [SLMs], digital micro-mirror devices [DMDs] or liquid crystal display [LCD] patterning devices

Abstract

A projection system comprises an array of lenses MLA, each lens transmitting a unique part of a patterned beam. Measuring devices measure a distance between the array of lenses MLA and a substrate W. A controller controls an actuator to adjust a position (e.g., height and/or tilt) of the microlens array MLA.

Claims

1. A lithographic apparatus, comprising:

an illumination system that conditions a radiation beam;

an array of individually controllable elements that pattern the beam;

a projection system that projects the patterned beam onto a target portion of a substrate and comprising an array of lenses arranged in a plane, such that each lens transmits a different part of the patterned beam;

a measuring device that measures a distance between a part of the substrate and a part of the array of lenses, the distance being measured perpendicular to the substrate; and

an actuator that adjusts a position of the array of lenses based on measurements by the measuring device wherein the adjusted position is substantially perpendicular to the plane.

2. The apparatus of claim 1, further comprising:

a plurality of the measuring devices, each of the measuring devices measuring a respective one of the distances between a different part of the substrate and a different part of the array of lenses.

3. The apparatus of claim 2, wherein the plurality of the measuring devices comprises three of the measuring devices.

4. The apparatus of claim 1, wherein the actuator adjusts the array of lenses to adjust a position of a plurality of points on the substrate.

5. The apparatus of claim 4, further comprising:

a plurality of the measuring devices; and

a plurality of the actuators,

wherein each of the measuring devices has a corresponding one of the actuators.

6. The apparatus of claim 1, further comprising:

a plurality of the measuring devices;

a plurality of the actuators; and

wherein data from each of the measuring devices is used to control a corresponding one of the actuators.

7. The apparatus of claim 1, wherein the measuring device measures the distance between the substrate and the array of lenses when the substrate is in a position to be exposed by the patterned beam.

8. The apparatus of claim 1, further comprising:

a storage element that stores data regarding the measured distance between the substrate and the array of lenses.

9. The apparatus of claim 1, wherein the measuring device is a contactiess distance sensor.

10. The apparatus of claim 1, wherein the actuator adjusts in three degrees of freedom.

11. The apparatus of claim 1, wherein the actuator bends the array of lenses based on measurements by the measuring device.

12. The apparatus of claim 1, wherein the measuring device is fixed to the array of lenses and moves with the array of lenses.

13. The apparatus of claim 1, wherein the measuring device is independent from the array of lenses.

14. A device manufacturing method, comprising:

(a) patterning a beam of radiation using an array of individually controllable elements;

(b) projecting the patterned beam onto a target portion of a substrate using a projection system;

(c) arranging an array of lenses arranged in a plane of the projection system, such that each lens in the array of lenses transmits a different part of the patterned beam;

(d) measuring a distance between the substrate and the array of lenses, the distance being measured perpendicular to the substrate; and

(e) adjusting a position of the array of lenses based on the measured distance wherein the adjusted position is substantially perpendicular to the plane.

15. The device manufacturing method according to claim 14, wherein steps (d) and (e) occur at substantially a same time for the substrate.

16. A method according to claim 14 wherein steps (d) and (e) occur at different times.

17. A lithographic apparatus, comprising:

an illumination system that conditions a radiation beam;

an array of individually controllable elements that pattern the beam;

a projection system that projects the patterned beam onto a target portion of a substrate and comprising an array of lenses arranged in a plane, such that each lens transmits a different part of the patterned beam;

a measuring device that measures a distance parallel to the beam between the substrate and the array of lenses; and

an actuator that adjusts a position of the array of lenses based on the measured distance wherein the adjusted position is substantially perpendicular to the plane.