Method and Apparatus for Generating Illuminating Radiation

• US 20170322497A1
• Filed: 05/02/2017
• Published: 11/09/2017
• Est. Priority Date: 05/04/2016
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: LIN, Nan, Roobol, Sander Bas, Mathijssen, Simon Gijsbert Josephus
• Granted Patent: US 10,048,596 B2
• Time in Patent Office: Days
• CPC Class Codes: G02F 1/353 Frequency conversion, i.e. wherein a light beam is generated with frequency components different from those of the incident light beams
• CPC Class Codes: G02F 1/354 Third or higher harmonic generation
• CPC Class Codes: G02F 2201/16 series; tandem
• CPC Class Codes: G03F 7/2004 characterised by the use of a particular light source, e.g. fluorescent lamps or deep UV light
• CPC Class Codes: G03F 7/70 Microphotolithographic exposure; Apparatus therefor photo-masks G03F1/00
• CPC Class Codes: G03F 7/70033 by plasma extreme ultraviolet [EUV] sources
• 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: G03F 7/70625 Dimensions, e.g. line width, critical dimension [CD], profile, sidewall angle or edge roughness
• CPC Class Codes: G03F 7/70633 Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching
• CPC Class Codes: G21K 5/04 with beam-forming means
• CPC Class Codes: H05G 2/00 Apparatus or processes specially adapted for producing X-rays, not involving X-ray tubes, e.g. involving generation of a plasma X-ray lasers H01S4/00

Abstract

An method for generating illuminating radiation in an illumination apparatus for use in an inspection apparatus for use in lithographic processes is described. A driving radiation beam is provided that comprises a plurality of radiation pulses. The beam is split into first and second pluralities of driving radiation pulses. Each plurality of driving radiation pulses has a controllable characteristic. The first and second pluralities may be used to generate an illuminating radiation beam with an output wavelength spectrum. The first and second controllable characteristics are controlled so as to control first and second portions respectively of the output wavelength spectrum of the illuminating radiation beam.

Claims

1-22. -22. (canceled)

23. A method for generating an illuminating radiation beam in a higher harmonic generation radiation source, comprising:

providing a driving radiation beam, the radiation beam comprising a plurality of radiation pulses, for generating the illuminating radiation beam;

splitting the driving radiation beam into first plurality of driving radiation pulses and a second plurality of driving radiation pulses;

controlling a first controllable characteristic of the first plurality of radiation pulses to control a first portion of an output wavelength spectrum of the illuminating radiation beam; and

controlling a second controllable characteristic of the second plurality of radiation pulses to control a second portion of the output wavelength spectrum of the illuminating radiation beam.

24. The method of claim 23, wherein controlling a first controllable characteristic comprises controlling a delay of the first plurality of radiation pulses relative to the second plurality of radiation pulses by a specific delay value.

25. The method of claim 23, wherein at least one of the first controllable characteristic or the second controllable characteristic is controlled so as to respectively cause the first portion or the second portion of the output wavelength spectrum to comprise a single wavelength continuum.

26. The method of claim 23, wherein at least one of the controlling the first controllable characteristic or the controlling the second controllable characteristic comprises controlling a generation time window for higher harmonic generation of at least one pulse of the second plurality of driving radiation pulses.

27. The method of claim 26, wherein at least one of the controlling the first controllable characteristic or the controlling the second controllable characteristic comprises performing gating on at least one of the first plurality of driving radiation pulses or the second plurality of driving radiation pulses.

28. The method of claim 26, further comprising performing generalized double optical gating on at least one of the first plurality of driving radiation pulses or the second plurality of driving radiation pulses.

29. The method of claim 26, wherein at least one of the controlling the first controllable characteristic or the controlling the second controllable characteristic comprises performing pulse compression on at least one of the first plurality of driving radiation pulses or the second plurality of driving radiation pulses.

30. The method claim 23, wherein at least one of the first controllable characteristic or the second controllable characteristic is controlled such that the second portion of the output wavelength spectrum is different from the first portion of the output wavelength spectrum.

31. A method for an inspection apparatus, comprising:

providing a first plurality of driving radiation pulses;

providing a second plurality of driving radiation pulses;

combining the first and second plurality of output pulses into an illuminating radiation beam; and

using the illuminating radiation beam to determine at least one characteristic of a target;

wherein the providing the first plurality of radiation pulses comprises controlling a first controllable characteristic of the first plurality of radiation pulses to control a first portion of an output wavelength spectrum of the illuminating radiation; and

wherein the providing a second plurality of radiation pulses comprises controlling a second controllable characteristic of the second plurality of radiation pulses to control a second portion of the output wavelength spectrum of the illuminating radiation.

32. The method of claim 31, wherein the controlling the first controllable characteristic comprises controlling a delay of the first plurality of radiation pulses relative to the second plurality of radiation pulses by a specific delay value.

33. The method of claim 31, wherein at least one of the first controllable characteristic or the second controllable characteristic is controlled so as to respectively cause the first portion or the second portion of the output wavelength spectrum to comprise a single wavelength continuum.

34. The method of claims 31, wherein at least one of the controlling the first controllable characteristic or the controlling the second controllable characteristic comprises controlling a generation time window for higher harmonic generation of at least one pulse of the second plurality of driving radiation pulses.

35. The method of claim 34, wherein at least one of the controlling the first controllable characteristic or the controlling the second controllable characteristic comprises performing gating on the second plurality of driving radiation pulses.

36. The method of claim 34, further comprising performing generalized double optical gating on at least one of the first or second plurality of driving radiation pulses.

37. A method of manufacturing devices, comprising:

forming device features and metrology targets on a series of substrates by a lithographic process;

measuring properties of the metrology targets on one or more processed substrates by a method comprising;

providing a first plurality of driving radiation pulses;

providing a second plurality of driving radiation pulses;

combining the first and second plurality of output pulses into an illuminating radiation beam; and

using the illuminating radiation beam to determine at least one characteristic of the metrology targets, wherein;

the providing the first plurality of radiation pulses comprises controlling a first controllable characteristic of the first plurality of radiation pulses to control a first portion of an output wavelength spectrum of the illuminating radiation; and

the providing a second plurality of radiation pulses comprises controlling a second controllable characteristic of the second plurality of radiation pulses to control a second portion of the output wavelength spectrum of the illuminating radiation

wherein the measured properties are used to adjust parameters of the lithographic process for the processing of further substrates.

38. A computer program product comprising machine-readable instructions for causing a processor to perform operations comprising:

providing a driving radiation beam, the radiation beam comprising a plurality of radiation pulses, for generating the illuminating radiation beam;

splitting the driving radiation beam into first plurality of driving radiation pulses and a second plurality of driving radiation pulses;

controlling a first controllable characteristic of the first plurality of radiation pulses to control a first portion of an output wavelength spectrum of the illuminating radiation beam; and

controlling a second controllable characteristic of the second plurality of radiation pulses to control a second portion of the output wavelength spectrum of the illuminating radiation beam.

39. A computer program product comprising machine-readable instructions for causing a processor to perform operations comprising:

providing a first plurality of driving radiation pulses;

providing a second plurality of driving radiation pulses;

combining the first and second plurality of output pulses into an illuminating radiation beam; and

using the illuminating radiation beam to determine at least one characteristic of a target;

wherein the providing the first plurality of radiation pulses comprises controlling a first controllable characteristic of the first plurality of radiation pulses to control a first portion of an output wavelength spectrum of the illuminating radiation; and

wherein the providing a second plurality of radiation pulses comprises controlling a second controllable characteristic of the second plurality of radiation pulses to control a second portion of the output wavelength spectrum of the illuminating radiation.

40. A lithographic system comprising:

an illumination optical system arranged to illuminate a pattern;

a projection optical system arranged to project an image of the pattern onto a substrate; and

an inspection apparatus configured to;

provide a driving radiation beam, the radiation beam comprising a plurality of radiation pulses, for generating the illuminating radiation beam;

split the driving radiation beam into first plurality of driving radiation pulses and a second plurality of driving radiation pulses;

control a first controllable characteristic of the first plurality of radiation pulses to control a first portion of an output wavelength spectrum of the illuminating radiation beam; and

control a second controllable characteristic of the second plurality of radiation pulses to control a second portion of the output wavelength spectrum of the illuminating radiation beam;

wherein the lithographic system is arranged to use one or more parameters calculated by the inspection apparatus in applying the pattern to further substrates.

41. A lithographic system comprising:

an illumination optical system arranged to illuminate a pattern;

a projection optical system arranged to project an image of the pattern onto a substrate; and

an inspection apparatus configured to;

provide a first plurality of driving radiation pulses;

provide a second plurality of driving radiation pulses;

combine the first and second plurality of output pulses into an illuminating radiation beam; and

use the illuminating radiation beam to determine at least one characteristic of a target;

wherein the providing the first plurality of radiation pulses comprises controlling a first controllable characteristic of the first plurality of radiation pulses to control a first portion of an output wavelength spectrum of the illuminating radiation; and

wherein the providing a second plurality of radiation pulses comprises controlling a second controllable characteristic of the second plurality of radiation pulses to control a second portion of the output wavelength spectrum of the illuminating radiation.