Lithographic apparatus and device manufacturing method

• US 20070252967A1
• Filed: 02/08/2007
• Published: 11/01/2007
• Est. Priority Date: 10/18/2004
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Bleeker, Arno, Troost, Kars
• Granted Patent: US 7,965,380 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 7/70425 Imaging strategies, e.g. for increasing throughput or resolution, printing product fields larger than the image field or compensating lithography- or non-lithography errors, e.g. proximity correction, mix-and-match, stitching or double patterning
• CPC Class Codes: G03F 7/70516 Calibration of components of the microlithographic apparatus, e.g. light sources, addressable masks or detectors

Abstract

Lithographic apparatus using an array of individually controllable elements in which a fraction of the intensity of the beam of radiation patterned by the array of individually controllable elements is diverted to an image sensor for verifying the quality of the image generated.

Claims

1. A lithographic apparatus, comprising:

an illumination system that conditions a beam of radiation;

an array of individually controllable elements that pattern the beam;

a beam divider that divides an intensity of the patterned beam into at least first and second fractions, each having substantially a complete cross-section of the pattern;

a projection system that projects the first fraction of the patterned beam onto a target portion of a substrate;

an image sensor that inspects at least a portion of the cross-section of the second fraction of the patterned beam; and

an actuator that moves the image sensor to select the portion of the cross-section of the second fraction of the patterned beam that is inspected

2. A lithographic apparatus, comprising:

an illumination system that conditions a beam of radiation;

an array of individually controllable elements that pattern the beam;

a beam divider that divides an intensity of the patterned beam into at least first and second fractions, each having substantially a complete cross-section of the pattern;

a projection system that projects the first fraction of the patterned beam onto a target portion of a substrate;

an image sensor that inspects at least a portion of the cross-section of the second fraction of the patterned beam; and

one or more moveable optical components and associated actuators configured to select the portion of the cross-section of the second fraction of the patterned beam that is inspected

3. A lithographic apparatus, comprising:

an illumination system that conditions a beam of radiation;

an array of individually controllable elements that pattern the beam;

a beam divider that divides an intensity of the patterned beam into at least first and second fractions, each having substantially a complete cross-section of the pattern;

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

an image sensor that inspects at least a portion of the cross-section of the second fraction of the patterned beam, wherein the portion of the patterned beam inspected by the image sensor is magnified.

4. A lithographic apparatus, comprising:

an illumination system that conditions a beam of radiation;

an array of individually controllable elements that pattern the beam;

a beam divider that divides an intensity of the patterned beam into at least first and second fractions, each having substantially a complete cross-section of the pattern;

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

an image sensor that inspects at least a portion of the cross-section of the second fraction of the patterned beam,

wherein a number of sensing pixels in the image sensor is greater than a number of individually controllable elements in the array of individually controllable elements corresponding to the portion of the cross-section of the patterned beam that is inspected by the image sensor.

5. The lithographic apparatus of claim 4, wherein the number of sensing pixels in the image sensor is at least four times or greater than the number of individually controllable elements in the array of individually controllable elements corresponding to the portion of the cross-section of the patterned beam that is inspected by the image sensor.

6. A lithographic apparatus, comprising:

an illumination system that conditions a beam of radiation;

an array of individually controllable elements that pattern the beam;

a beam divider that divides an intensity of the patterned beam into at least first and second fractions, each having substantially a complete cross-section of the pattern;

a projection system that projects the first fraction of the patterned beam onto a target portion of a substrate;

an image sensor that inspects at least a portion of the cross-section of the second fraction of the patterned beam; and

a controller that compares an image detected by the image sensor with a corresponding portion of an image intended to be projected into the substrate, wherein the controller adjusts a calibration control of the array of individually controllable elements or calibrates or adjusts the array of individually controllable elements based on a difference between the image detected by the image sensor and the intended image.

7. A lithographic apparatus, comprising:

an illumination system that conditions a beam of radiation;

an array of individually controllable elements that pattern the beam;

a beam divider that divides an intensity of the patterned beam into at least first and second fractions, each having substantially a complete cross-section of the pattern;

a projection system that projects the first fraction of the patterned beam onto a target portion of a substrate;

an image sensor that inspects at least a portion of the cross-section of the second fraction of the patterned beam; and

a controller that compares an image detected by the image sensor with a corresponding portion of an image intended to be projected into the substrate, wherein the controller identifies from one or more exposures which, if any, of the individually controllable elements in the array of individually controllable elements fail to adequately respond to control signals intended to control that individually controllable element, and wherein the controller uses the identification to calibrate or adjust the individually controllable elements prior to exposure of the substrate.

8. A lithographic apparatus, comprising:

an illumination system that conditions a beam of radiation;

an array of individually controllable elements that pattern the beam;

a beam divider that divides an intensity of the patterned beam into at least first and second fractions, each having substantially a complete cross-section of the pattern;

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

an image sensor that inspects at least a portion of the cross-section of the second fraction of the patterned beam and calibrates control of the individually controllable elements prior to exposure of the substrate.