Lithographic apparatus and device manufacturing method utilizing a continuous light beam in combination with pixel grid imaging

• US 7,251,019 B2
• Filed: 07/20/2005
• Issued: 07/31/2007
• Est. Priority Date: 07/20/2005
• Status: Expired due to Fees

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Tinnemans, Patricius Aloysius Jacobus, De Jager, Pieter Willem Herman
• Primary Examiner(s): Nguyen; Henry Hung
• Assistant Examiner(s): LIU, CHIA HOW MICHAEL
• Application Number:
  US11/185,024
• Publication Number:
  US 20070019174A1
• Time in Patent Office: 741 Days
• Field of Search: 355/55, 355/53, 355/67
• US Class Current: 355/55
• 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: G03F 7/70358 Scanning exposure, i.e. relative movement of patterned beam and workpiece during imaging

Abstract

A continuous source of radiation, for example a lamp, is used in conjunction with pixel grid imaging. In one example, the individually controllable elements operate at a frequency of at least about 50 kHz. To compensate for any distortion of an exposed spot a point spread function is adjusted to be shorter in a scanning direction.

Claims

1. A lithographic apparatus, comprising:

an illumination system that supplies a continuous beam of radiation;

an array of individually controllable elements that modulate the radiation beam and configured to produce a first set of sub-beams from the radiation beam, the first set of sub-beams having oblong or elliptical cross-sectional shapes;

a substrate mover that continuously moves a substrate in a first direction relative to the radiation beam; and

a projection system that is configured to transform the first set of sub-beams into a second set of sub-beams having a circular cross-section shape and to project the second set of sub-beams onto a target portion of the substrate, the projection system comprising, a microlens array, each microlens in the microlens array having an oblong or elliptical shape, wherein each microlens receives a respective portion of the first set of sub-beams of radiation to form respective portions of the second set of sub-beams of radiation.

2. The lithographic apparatus of claim 1, wherein elements in the array of individually controllable elements are configured to be switched ON and OFF at a rate of at least about 50 kHz.

3. The lithographic apparatus of claim 1, further comprising a controller that sets the state of at least a portion of the individually controllable elements sequentially.

4. The lithographic apparatus of claim 3, wherein the state of the at least a portion of the individually controllable elements is set one at a time through setting one by one.

5. The lithographic apparatus of claim 3, wherein the state of the at least a portion of the individually controllable elements is set a row at a time through setting row by row.

6. The lithographic apparatus of claim 3, wherein the state of the at least a portion of the individually controllable elements is set a group at a time through setting a group of the individually controllable elements by a group of the individually controllable elements.

7. The lithographic apparatus of claim 1, further comprising a lamp configured to produce the continuous beam of radiation.

8. The lithographic apparatus of claim 7, wherein the lamp is a Hg lamp.

9. The lithographic apparatus of claim 1, wherein at a focal point of at least one of the microlenses a maximum length of across-section of a corresponding one of the sub-beams of radiation in the second set of sub-beams is shorter in the first direction than in a second direction perpendicular to the first direction.

10. A device manufacturing method, comprising:

forming a first set of patterned sub-beams of radiation having oblong or elliptical cross-sectional shapes through patterning a continuous beam of radiation using an array of individually controllable elements;

scanning a substrate;

receiving respective portions of the first set of patterned sub-beams of radiation on respective microlenses in a microlenses array, each of the respective microlenses having oblong or elliptical shapes; and

forming a second set of patterned sub-beams of radiation that are projected onto target portions of the scanning substrate using the respective microlenses, the second set of patterned sub-beams of radiation having circular cross-sectional shapes.

11. The device manufacturing method according to claim 10, wherein a state of a portion of the array of individually controllable elements is set sequentially.