SPATIAL WAVEFRONT ANALYSIS AND 3D MEASUREMENT

• US 20110149298A1
• Filed: 09/03/2009
• Published: 06/23/2011
• Est. Priority Date: 01/24/2002
• Status: Abandoned Application

• Current Assignee: Icos Vision Systems NV (KLA Corporation)
• Original Assignee: Icos Vision Systems NV (KLA Corporation)
• Inventors: Lanzmann, Emmanuel, Wolfling, Shay, Banitt, David, Levavi, Shay, Saban, Yoram, Weitzman, Yosi, Arieli, Yoel
• Application Number:
  US12/553,927
• Publication Number:
  US 20110149298A1
• Time in Patent Office: Days
• US Class Current: 356/521
• CPC Class Codes: G01B 9/02087 Combining two or more images of the same region
• CPC Class Codes: G01J 9/02 by interferometric methods using interferometers for measuring optically the linear dimensions of objects G01B9/02
• CPC Class Codes: G11B 7/005 Reproducing G11B7/0065 takes precedence
• CPC Class Codes: G11B 7/0051 involving phase depth effects
• CPC Class Codes: G11B 7/24088 for storing more than two values, i.e. multi-valued recording for data or prepits

Abstract

A method of wavefront (100) analysis including applying a transform to the wavefront, applying a plurality of different phase changes (110, 112, 114) to the transformed wavefront (108), obtaining a plurality of intensity maps (130, 132, 134) wherein the plurality of different phase changes are applied to region of the transformed wavefront, corresponding to a shape of the light source.

Claims

1-49. -49. (canceled)

50. A method for effecting phase change of a wavefront comprising:

applying a plurality of different phase changes to said wavefront, thereby to obtain a plurality of differently phase changed wavefronts,

wherein said step of applying a plurality of different phase changes comprises providing an optical system having a selectable plurality of optical configurations creating a corresponding plurality of phase changes respectively, and

wherein said optical system comprises a spatial light modulator (SLM) including a central inactive area and a peripheral active area.

51. A method for effecting phase change of a wavefront comprising:

applying a plurality of different phase changes to said wavefront, thereby to obtain a plurality of differently phase changed wavefronts,

wherein said step of applying a plurality of different phase changes comprises providing an optical system having a selectable plurality of optical configurations creating a corresponding plurality of phase changes respectively, and

wherein said optical system comprises a phase plate having a plurality of portions each corresponding to an individual phase change and a phase plate portion selector operative to position a selected one of the phase plate portions along a light path.

52-55. -55. (canceled)

56. A method for effecting phase change of a wavefront which comprises:

applying a plurality of different phase changes to said wavefront, thereby to obtain a plurality of differently phase changed wavefronts,

wherein said step of applying a plurality of different phase changes comprises providing an optical system having a selectable plurality of optical configurations creating a corresponding plurality of phase changes respectively, and

wherein said optical system comprises two mirrors at an adjustable distance from one another whose relative configuration is such that a first portion of the light impinging at the two minor configuration arrives at the first minor and a second portion of the tight impinging at the two minor configuration arrives at the second minor.

57. A method according to claim 56 wherein said two mirrors comprise a first minor preceding a second mirror along the light path and having an aperture defined therewith, thereby allowing said second portion of the light to reach the second minor via the aperture.

58. A method according to claim 56 wherein said two mirrors comprise a first minor preceding a second minor along the light path wherein at least one dimension of the first mirror'"'"'s surface area is less than at least one corresponding dimension of the cross-section of the wavefront and less than the corresponding dimension of the second mirror'"'"'s surface area, thereby allowing said second portion of the light to reach the second minor.

59. A method according to claim 56 and also comprising at least one piezo-electric actuator operative to allow a user to control the distance between the two mirrors.

60-66. -66. (canceled)

67. A method for wavefront analysis comprising:

forming a real image of an object at an image plane;

analyzing an image wavefront corresponding to said real image at said image plane; and

utilizing results of said analyzing to reconstruct an object wavefront, corresponding to said object.

68. A method for wavefront analysis according to claim 67 and wherein said analyzing takes place following forming said real image.

69. A method for wavefront analysis according to claim 67 and wherein said analyzing an image wavefront comprises:

obtaining a plurality of differently phase changed transformed image wavefronts corresponding to an image wavefront being analyzed which has an amplitude and a phase;

obtaining a plurality of intensity maps of said plurality of phase changed transformed image wavefronts; and

employing said plurality of intensity maps to obtain an output indicating said amplitude and phase of said image wavefront being analyzed.

70. A method for wavefront analysis according to claim 67 and wherein said analyzing an image wavefront comprises interfering said wavefront with a wavefront reflected from a reference surface.

71. A method for wavefront analysis according to claim 67 and wherein said analyzing an image wavefront comprises spatially splitting the wavefront into two parts and interfering one part with the other in a common-path manner.

88. A method for wavefront analysis according to claim 69 and wherein:

said object wavefront is a surface mapping wavefront obtained by reflecting radiation from a surface of said object, said surface mapping wavefront having an amplitude and a phase;

said image wavefront is an image surface mapping wavefront; and

said output indicating said amplitude and phase of said image wavefront being analyzed is employed to obtain an output indicating said surface of said object.

89. A method for wavefront analysis according to claim 69 and wherein:

said object wavefront is an object inspection wavefront obtained by transmitting radiation through said object, said object inspection wavefront having an amplitude and a phase;

said image wavefront is an image object inspection wavefront; and

said output indicating said amplitude and phase of said image wavefront being analyzed is employed to obtain an output indicating optical and thickness properties of said object.

90. A method for wavefront analysis according to claim 69 and wherein:

said object wavefront is a spectral analysis wavefront obtained by causing radiation to impinge on an object, said spectral analysis wavefront having an amplitude and a phase;

said image wavefront is an image spectral analysis wavefront; and

said output indicating said amplitude and phase of said image wavefront being analyzed is employed to obtain an output indicating spectral content of said radiation.

72. A wavefront analysis system comprising:

an imager, forming a real image of an object at an image plane;

a wavefront analyzer, analyzing an image wavefront corresponding to said real image at said image plane; and

an object wavefront reconstructor, utilizing an output of said image wavefront analyzer to reconstruct an object wavefront, corresponding to said object.

73. A wavefront analysis system according to claim 72 and wherein said wavefront analyzer comprises:

a wavefront transformer, operative to provide a plurality of differently phase changed transformed wavefronts corresponding to said image wavefront which has an amplitude and a phase;

an intensity map generator, operative to provide a plurality of intensity maps of said plurality of phase changed transformed wavefronts; and

an intensity map utilizer, employing said plurality of intensity maps to provide an output indicating said amplitude and phase of said image wavefront.

75. A wavefront analysis system according to claim 72 and also comprising:

a wavefront interference generator, generating an interference of said wavefront with a wavefront reflected from a reference surface.

76. A wavefront analysis system according to claim 72 and also comprising:

a wavefront splitter, spatially splitting said image wavefront into first and second parts; and

a wavefront interference generator, generating an common-path interference of said first part with said second part.

77. A wavefront analysis system according to claim 72 and wherein said imager is an optical microscope.

78. A wavefront analysis system according to claim 72 and wherein said image plane is any plane.

79. A wavefront analysis system according to claim 72 wherein said imager is a revolving turret with at least one commercial objective.

80. A wavefront analysis system according to claim 73 and wherein:

said wavefront transformer comprises an optical manipulator and an Optics-, and said intensity map generator comprises a CCD camera.

74. (canceled)

81-87. -87. (canceled)

91-106. -106. (canceled)