Lithographic apparatus and device manufacturing method

• US 7,336,343 B2
• Filed: 11/14/2006
• Issued: 02/26/2008
• Est. Priority Date: 07/27/2004
• Status: Expired due to Fees

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: De Jager, Pieter Willem Herman
• Primary Examiner(s): MATHEWS, ALAN A
• Application Number:
  US11/598,791
• Publication Number:
  US 20070052943A1
• Time in Patent Office: 469 Days
• Field of Search: 355/53, 355/67, 355/71, 355/77, 359/224, 359/619, 430/311
• US Class Current: 355/71
• 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
• CPC Class Codes: Y10S 359/904 Micromirror

Abstract

A lithographic apparatus and method include an illumination system that supplies a beam of radiation, an array of individually controllable elements that pattern the beam, and a projection system that directs the patterned beam a substrate supported on a substrate table. The projection system defines a pupil. Either the pupil or the array of individually controllable elements is imaged onto a target portion of the substrate. The projection system includes an array of lenses with each lens in the array arranged to direct a respective part of the patterned beam onto a respective part of the target portion of the substrate. In one example, each of the individually controllable elements is selectively controllable to direct a respective part of the beam away from the pupil such that the proportion of the beam passing through the pupil is adjusted. In one example, the individually controllable elements are arranged in groups, such that radiation deflected by each element in one group is directed towards the same lens in the lens array. In one example, the individually controllable elements in any one group are controlled together to direct radiation in different directions away from the pupil, such that the pattern imparted to the beam by that group of elements is substantially symmetrical with respect to the pupil.

Claims

1. A lithographic apparatus, comprising:

an illumination system configured to condition a beam of radiation;

an array of individually controllable elements configured to pattern the beam; and

a projection system configured to project the patterned beam onto a target portion of a substrate, the projection system defining a pupil and comprising an array of lenses, wherein the array of lenses is arranged to direct a respective part of the patterned beam towards a respective part of the target portion of the substrate,

wherein the individually controllable elements are arranged in groups, such that the patterned beam is directed by each element in each respective group towards a corresponding lens in the lens array, and

wherein the individually controllable elements in each group are controlled together to direct the patterned beam away from the pupil, whereby a pattern imparted onto the beam by that group of individually controllable elements is substantially symmetrical with respect to the pupil.

2. The apparatus of claim 1, wherein the individual elements in each of the groups are configured to direct the patterned beam in different directions away from the pupil.

3. The apparatus of claim 1, wherein the individually controllable elements are selectively controllable to progressively direct a respective part of the patterned beam away from the pupil, whereby an amount of the patterned beam passing through the pupil is progressively varied.

4. The apparatus of claim 1, wherein each of the groups of the individually controllable elements comprises two elements that progressively direct the patterned beam away from the pupil in directions inclined by 180°

with respect to each other.

5. The apparatus of claim 1, wherein the groups of the individually controllable elements comprises three elements that progressively direct the patterned beam away from the pupil in directions inclined at 120°

intervals with respect to each other.

6. The apparatus of claim 1, wherein the groups of the individually controllable elements comprises four elements that progressively direct radiation away from the pupil in directions inclined at 90°

intervals with respect to each other.

7. The apparatus of claim 1, wherein the individually controllable elements are mirrors that are tilted progressively away from a position in which the beam reflected by that mirror is symmetrical with respect to the pupil.

8. The apparatus of claim 1, further comprising:

a beam splitter configured to reflect the beam from the illumination system toward the individual controllable elements and to transmit the patterned beam from the individually controllable elements towards the array of lenses.

9. The apparatus of claim 1, wherein the pupil is defined by a projection lens contrast aperture plate.

10. A device manufacturing method, comprising:

(a) controlling individually controllable elements in an array of individually controllable element in groups to pattern a beam of radiation;

(b) selectively controlling the individually controllable elements to direct a respective part of the patterned beam away from a pupil in a projection system;

(c) using the individually controllable elements in each of the groups to direct the patterned beam towards a same lens in an array of lenses in a projection system;

(d) projecting the patterned beam onto a target portion of a substrate using the array of lenses in the projection system; and

(e) using the individually controllable elements to direct the patterned beam of radiation away from the pupil, whereby the pattern imparted to the beam by each of the groups is substantially symmetrical with respect to the pupil.

11. The method of claim 10, wherein step (e) directs the patterned beam in different directions away from the pupil.

12. The method of claim 11, wherein step (e) progressively directs the pattered beam in the different directions.

13. The method of claim 10, wherein step (d) wherein an amount of the patterned beam passing through the pupil is progressively varied.

14. The method of claim 10, further comprising:

forming one of the groups with two of the individually controllable elements, which are progressively adjusted to direct the patterned beam away from the pupil in directions inclined by 180°

with respect to each other.

15. The method of claim 10, further comprising:

forming one of the groups with three of the individually controllable elements, which are progressively adjusted to direct the patterned beam away from the pupil in directions inclined by 120°

with respect to each other.

16. The method of claim 10, further comprising:

forming one of the groups with four of the individually controllable elements, which are progressively adjusted to direct the patterned beam away from the pupil in directions inclined by 90°

with respect to each other.

17. The method of claim 10, further comprising:

using mirrors as the individually controllable elements, wherein the mirrors are tilted away from a position in which the patterned beam deflected by each of the mirrors is symmetrical with respect to the pupil.

18. The method of claim 10, further comprising:

directing the beam towards the individual controllable elements using a beam splitter; and

directing the patterned beam from the individually controllable elements towards the array of lenses via the beam splitter.

19. The method of claim 10, wherein a projection lens contrast aperture is positioned to define the pupil.