Radiation source, lithographic apparatus, and device manufacturing method

• US 20050116183A1
• Filed: 09/30/2004
• Published: 06/02/2005
• Est. Priority Date: 10/09/2003
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Sinke, Arnold
• Granted Patent: US 7,109,498 B2
• Time in Patent Office: Days
• US Class Current: 250/492.200
• 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 7/70575 Wavelength control, e.g. control of bandwidth, multiple wavelength, selection of wavelength or matching of optical components to wavelength
• CPC Class Codes: H01L 33/32 containing nitrogen

Abstract

A radiation source for use in lithography. The radiation source comprising a pn-junction disposed on a substrate that can be reverse-biased to cause avalanche breakdown and emission of UV or DUV radiation by deceleration of electrons accelerated into an n-type region of the pn-junction. The radiation source can have a low operating voltage, a high switching speed, and provides great design freedom. High intensity can be provided, e.g., by the use of large or multiple sources. The pn-junction can be doped with impurities to increase emission of radiation at a desired frequency and increase the efficiency of the device. For protection, the pn-junction may be covered by a layer of transparent oxide. By reverse biasing the pn-junction with a potential difference at least 4V, radiation of wavelength 300 nm or less can be obtained. The pn-junction source of the present invention can replace conventional radiation sources and be using in connection with a mask/contrast device, or can be used to replace both the conventional radiation source and the mask/contrast device.

Claims

1. A radiation source for imaging in a lithography system, said radiation source comprising:

a substrate, and

a pn-junction disposed on the substrate, the pn-junction being reverse-biased to cause avalanche breakdown and emission of UV or DUV radiation through deceleration of electrons accelerated into an n-type region of said pn-junction.

2. The radiation source of claim 1, wherein said pn-junction is doped with impurities to increase emission of radiation at a desired frequency.

3. The radiation source of claim 1, wherein said pn-junction is covered by a layer of transparent oxide.

4. The radiation source of claim 1, further comprising:

a voltage source that provides a potential difference of at least about 4V to reverse bias the pn-junction.

5. The radiation source of claim 1, further comprising:

a voltage source that provides a potential difference of about 5V to reverse bias the pn-junction.

6. The radiation source of claim 1, further comprising:

a filter that selects a desired range of wavelengths from the radiation emitted by said pn-junction.

7. The radiation source of claim 1, further comprising:

a plurality of selectively addressable elements, each element comprising a respective one of the pn-junction.

8. A lithographic apparatus, comprising:

a patterning device; and

a radiation source, the radiation source comprising,

a substrate, and

a pn-junction disposed on the substrate, the pn-junction being reverse-biased to cause avalanche breakdown and emission of UV or DUV radiation by deceleration of electrons accelerated into an n-type region of said pn-junction,

whereby a pattern formed when radiation from the radiation source interacts with the patterning device is transferred onto a substrate.

9. A lithographic apparatus, comprising:

an illumination system that provides a beam of radiation, the illumination system comprising,

a support structure that supports a patterning device, the patterning device patterning the beam;

a projection system that projects the patterned beam onto a target portion of a substrate,

wherein the illumination system comprises a radiation source including a pn-junction disposed on a substrate, the pn-junction being reverse-biased to cause avalanche breakdown and emission of UV or DUV radiation by deceleration of electrons accelerated into an n-type region of said pn-junction.

10. The lithographic apparatus of claim 9, wherein the illumination system further comprises:

an illumination optical system that projects an image of said radiation source onto a pupil plane of the projection system,

wherein said support structure supports said patterning device at a plane that is a Fourier transform of the plane of said radiation source.

11. A lithographic apparatus, comprising:

a radiation source serving as patterning means, said radiation source comprising a plurality of selectively addressable elements, each element comprising a pn-junction disposed on a substrate, the pn-junctions having an ability to be reverse-biased to cause avalanche breakdown and emission of UV or DUV radiation by deceleration of electrons accelerated into an n-type region of said pn-junction; and

a projection system that projects an image of the radiation source onto a target portion of a substrate.

12. A device manufacturing method, comprising:

reverse biasing a pn-junction to cause avalanche breakdown and emission of UV or DUV radiation by deceleration of electrons accelerated into the n-type region of said pn-junction, which generates a patterned beam of radiation;

projecting the pattered beam of radiation onto a target portion of a substrate.