Radiation source, lithographic apparatus, and device manufacturing method

• US 7,109,498 B2
• Filed: 09/30/2004
• Issued: 09/19/2006
• 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
• Primary Examiner(s): Lee, John R.
• Assistant Examiner(s): Hashmi, Zia R.
• Application Number:
  US10/953,472
• Publication Number:
  US 20050116183A1
• Time in Patent Office: 719 Days
• Field of Search: None
• US Class Current: 250/492.2
• 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 lithographic apparatus, comprising:

a radiation source including a plurality of selectively addressable pn-junction elements, the radiation source generating patterned radiation through selective addressing of the plurality of selectively addressable pn-junction elements; and

a projection system that projects the patterned radiation generated by the radiation source onto a target portion of a substrate.

2. The lithographic apparatus of claim 1, wherein each of the pn-junction elements is doped with impurities to increase emission of radiation at a desired frequency.

3. The lithographic apparatus of claim 1, wherein each of the pn-junction elements is covered by a layer of transparent oxide.

4. The lithographic apparatus of claim 1, further comprising:

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

5. The lithographic apparatus of claim 1, further comprising:

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

6. The lithographic apparatus of claim 1, further comprising:

a filter that selects a desired range of wavelengths from the radiation emitted by selectively addresses ones of the pn-junction elements.

7. A lithographic method used to manufacture a device, comprising:

selectively addressing an array of pn-junction elements to form a patterned beam of radiation; and

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

8. The method of claim 7, further comprising:

doping the pn-junction elements with impurities to increase emission of radiation at a desired frequency.

9. The method of claim 7, further comprising:

covering the pn-junction elements with layer of transparent oxide.

10. The method of claim 7, further comprising:

providing a potential difference of at least about 4V to reverse bias the selectively addresses ones of the pn-junction elements.

11. The method of claim 7, further comprising:

providing a potential difference of about 5V to reverse bias the selectively addresses ones of the pn-junction elements.

12. The method of claim 7, further comprising:

filtering a desired range of wavelengths from the radiation emitted by the selectively addressed pn-junction elements.