Lithographic apparatus and device manufacturing method

• US 20060119825A1
• Filed: 12/02/2004
• Published: 06/08/2006
• Est. Priority Date: 12/02/2004
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Munnig Schmidt, Robert-Han
• Granted Patent: US 7,391,499 B2
• Time in Patent Office: Days
• US Class Current: 355/67
• 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: G03F 7/70475 Stitching, i.e. connecting image fields to produce a device field, the field occupied by a device such as a memory chip, processor chip, CCD, flat panel display

Abstract

A lithographic apparatus for reducing the visibility of artifacts in the pattern is provided. The apparatus comprises an illumination system, a patterning device, a projecting system, and a modulating device. The illumination system supplies a beam of radiation. The patterning device patterns the beam. The projection system projects the beam onto a target portion of a substrate. The modulating device modulates the beam to impart the pattern with a modulation scheme.

Claims

1. A lithographic apparatus comprising:

an illumination system that supplies a beam of radiation;

a patterning device that patterns the beam;

a projection system that projects the beam onto a target portion of the substrate; and

a modulating device that modulates the beam to impart the pattern with a modulation scheme.

2. The apparatus of claim 1, wherein the modulating device is part of the illumination system.

3. The apparatus of claim 1, wherein the patterning device comprises an array of individually controllable elements.

4. The apparatus of claim 3, wherein the modulating device is arranged to apply the modulation scheme to elements of the array of individually controllable elements.

5. The apparatus of claim 1, wherein the modulating device comprises the array of individually controllable elements.

6. The apparatus of claim 1, wherein the modulating device is disposed in the optical path of the beam of radiation between the illumination system and the substrate.

7. The apparatus of claim 6, wherein the modulating device is disposed between the illumination system and the patterning device.

8. The apparatus of claim 6, wherein the modulating device is disposed between the patterning device and the substrate.

9. The apparatus of claim 1, wherein the modulating device applies a predetermined modulation scheme to the beam of radiation.

10. The apparatus of claim 1, wherein the modulating device applies a random modulation scheme to the beam of radiation.

11. The apparatus of claim 1, wherein the modulating device modulates the amplitude of the beam of radiation.

12. The apparatus of claim 1, wherein the modulating device modulates the frequency of the beam of radiation.

13. The apparatus of claim 1, further comprising:

a controller that selects a modulation scheme in accordance with the pattern of the beam of radiation.

14. The apparatus of claim 1, wherein the modulating device is arranged to modulate the beam of radiation in a portion of its cross-section.

15. The apparatus of claim 14, wherein the modulating device is arranged to modulate the beam of radiation only at its periphery.

16. A device manufacturing method, comprising:

patterning a beam of radiation;

projecting the patterned beam of radiation onto a target portion of a substrate; and

modulating the beam of radiation.

17. The method of claim 16, wherein the beam is imparted with a pattern using an array of individually controllable elements.

18. The method of claim 16, wherein the beam of radiation is modulated prior to the beam being imparted with a pattern.

19. The method of claim 16, wherein the beam of radiation is modulated after the beam has been imparted with a pattern.

20. The method of claim 16, wherein the step of modulating the beam of radiation comprises modulating the amplitude of the beam of radiation.

21. The method of claim 16, wherein the step of modulating the beam of radiation comprises modulating a frequency of the beam of radiation.