System for measuring polarimetric spectrum and other properties of a sample
DCFirst Claim
1. A method for measuring optically detectable properties of a sample, comprising:
- focusing a polarized sample beam of broadband radiation onto the sample, said beam having a multitude of polarization states;
collecting radiation modified by the sample by means of an objective; and
analyzing and dispersing the radiation modified by and collected from the sample to provide a polarimetric spectrum, wherein no substantial relative change in polarization state between the radiation and the sample beam is caused by relative motion between optical elements employed in the focusing, collecting and analyzing; and
deriving information on optically detectable properties of the sample from said polarimetric spectrum.
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Abstract
A polarized sample beam of broadband radiation is focused onto the surface of a sample and the radiation modified by the sample is collected by means of a mirror system in different planes of incidence. The sample beam focused to the sample has a multitude of polarization states. The modified radiation is analyzed with respect to a polarization plane to provide a polarimetric spectrum. Thickness and refractive information may then be derived from the spectrum. Preferably the polarization of the sample beam is altered only by the focusing and the sample, and the analyzing is done with respect to a fixed polarization plane. In the preferred embodiment, the focusing of the sample beam and the collection of the modified radiation are repeated employing two different apertures to detect the presence or absence of a birefringence axis in the sample. In another preferred embodiment, the above-described technique may be combined with ellipsometry for determining the thicknesses and refractive indices of thin films.
157 Citations
249 Claims
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1. A method for measuring optically detectable properties of a sample, comprising:
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focusing a polarized sample beam of broadband radiation onto the sample, said beam having a multitude of polarization states;
collecting radiation modified by the sample by means of an objective; and
analyzing and dispersing the radiation modified by and collected from the sample to provide a polarimetric spectrum, wherein no substantial relative change in polarization state between the radiation and the sample beam is caused by relative motion between optical elements employed in the focusing, collecting and analyzing; and
deriving information on optically detectable properties of the sample from said polarimetric spectrum. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
providing a reference beam;
detecting the reference beam to provide a reference spectrum; and
wherein said deriving comprises comparing said spectrum and said reference spectrum to obtain said information of the sample.
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22. The method of claim 1, said focusing or collecting being performed at least twice and within at least two different ranges of angles to a reference plane normal to a sample surface.
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23. The method of claim 22, said sample having different optically detectable properties along at least two axes, wherein said focusing or collecting are repeated employing at least two different apertures each aligned or centered respectively about one of said axes.
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24. The method of claim 23, wherein said at least two different apertures are substantially 90 degrees apart.
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25. The method of claim 1, wherein said focusing, collecting, dispersing and deriving are performed twice, once with polarization states of the sample beam and/or those of the modified and collected radiation within a first range of angles to a reference plane normal to a sample surface, and another time with said polarization states within a second different range of angles to the reference plane.
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26. The method of claim 25, further comprising polarizing the sample beam before it reaches the sample, and/or analyzing the radiation modified by and collected from the sample with a polarizing element so that radiation of the sample beam and/or the modified and collected radiation is polarized, with the polarizing element in two different positions when the focusing, collecting, dispersing and deriving are performed twice.
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27. The method of claim 26, wherein said two different positions are substantially 90 degrees apart by rotation.
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28. An apparatus for measuring optically detectable properties of a sample, comprising:
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first optics focusing a polarized sample beam of broadband radiation onto the surface of the sample, the sample beam having a multitude of polarization states, wherein said sampling beam is focused along directions substantially surrounding a line normal to said sample;
second optics collecting radiation modified by the sample, said second optics comprising an objective; and
an instrument analyzing and dispersing the radiation modified by and collected from the sample to provide a polarimetric spectrum, wherein no substantial relative change in polarization state between the radiation and the sample beam is caused by relative motion between the first and second optics and the instrument;
wherein said information on optically detectable properties of the sample is derivable from said polarimetric spectrum. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62)
a radiation source providing a beam of broadband radiation; and
third optics splitting said beam of broadband radiation into said polarized sample beam and said reference beam, wherein said first optics focuses said sample beam onto the sample so that the focused beam has a multitude of polarization states, wherein said polarization states are functions of an angle φ
to a reference plane normal to a sample surface, said angle φ
having a range defining a substantial angle of an illumination aperture.
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30. The apparatus of claim 29, wherein said first optics focuses said polarized beam along different planes of incidence onto the sample, said planes being at different angles .phi. to the reference plane, said angle of the illumination aperture being about 90 or 180 degrees.
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31. The apparatus of claim 29, said third optics comprising a totally reflecting mirror placed less than completely across said beam.
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32. The apparatus of claim 29, said third optics deflecting a portion of said radiation in the beam from the source into a sample beam, the undeflected portion of the radiation defining a reference radiation beam.
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33. The apparatus of claim 29, wherein information on optically detectable properties of the sample is derivable from a comparison of said polarimetric spectrum and said reference spectrum.
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34. The apparatus of claim 33, said radiation beam and said polarimetric and reference spectra comprising multiple wavelengths in a range from about 190 nm to about 830 nm.
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35. The apparatus of claim 29, wherein said third optics comprises a polarizing beam splitter.
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36. The apparatus of claim 29, wherein said third optics comprise a beam divider, said apparatus further comprising a polarizer.
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37. The apparatus of claim 36, said polarizer being in an optical path to the first optics and forms a part of the instrument.
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38. The apparatus of claim 36, said polarizer being in an optical path to the first optics, said instrument comprising an analyzer in an optical path from the second optics.
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39. The apparatus of claim 28, said instrument comprising an analyzer, said apparatus further comprising a polarizer passing a beam of broadband radiation to form said polarized sample beam, wherein during the focusing by the first optics and analyzing by the instrument, the polarizer and analyzer do not rotate.
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40. The apparatus of claim 28, wherein said first and second optics comprise a common objective that focuses the sample beam onto and collects radiation modified by the sample.
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41. The apparatus of claim 28, further comprising a flip-in polarizer and a device moving the polarizer into and out of a path of the beam of broadband radiation from a radiation source to provide the sample beam that is polarized or unpolarized.
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42. The apparatus of claim 41, wherein said polarizer polarizes the beam originating from the source and analyses the radiation modified by and collected from the sample.
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43. The apparatus of claim 28, further comprising a source of radiation, wherein said first optics focuses radiation from the source onto the sample, said sample having different optically detectable properties along at least two axes, said apparatus further comprising at least one aperture aligned with one of said axes, said aperture being in an optical path between the source and the instrument.
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44. The apparatus of claim 43, wherein said at least one aperture is centered about said one of the axes.
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45. The apparatus of claim 43, further comprising a mechanism selecting one of at least two apertures to be aligned with one of the axes.
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46. The apparatus of claim 45, wherein said mechanism causes each of two different apertures to be aligned with a corresponding one of the axes, so that the polarimetric spectra obtained when the two apertures are aligned consecutively with their corresponding axes yields information on optically detectable properties of the sample.
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47. The apparatus of claim 46, wherein said mechanism comprise a wheel with at least two apertures therein.
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48. The apparatus of claim 47, wherein said wheel comprise a polarizer in each of the at least two apertures.
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49. The apparatus of claim 47, wherein two of said at least two apertures have shapes substantially in the shape of a circle with one quadrant blocked.
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50. The apparatus of claim 28, further comprising a source of radiation, wherein said first optics focuses radiation from the source onto the sample, said sample having different optically detectable properties along at least two axes, said apparatus further comprising a mechanism rotating a linear polarizer in an optical path of the sample beam for detecting said axes.
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51. The apparatus of claim 28, said broadband radiation comprising multiple wavelengths in a range from about 190 nm to about 830 nm.
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52. The apparatus of claim 28, wherein said instrument analyzes the radiation modified by the sample with respect to a predetermined and fixed polarization plane.
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53. The apparatus of claim 28, further comprising a phase retarder in an optical path between the second optics and the instrument, said retarder altering phase of the modified radiation collected from the sample prior to analyzing and dispersing it.
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54. The apparatus of claim 53, wherein said retarder retards said phase of the modified and collected radiation by about π
- /4 radians.
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55. The apparatus of claim 28, said first or second optics comprising a mirror having a coating that introduces a total change in phase of radiation reflected by it by the first and second optics of about π
- /2 radians.
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56. The apparatus of claim 28, wherein said sample beam surrounds a line normal to a surface of the sample.
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57. The apparatus of claim 28, further comprising a common polarizing element that polarizes a sample beam before it is focused by the first optics, and that analyzes the radiation modified by and collected from the sample.
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58. The apparatus of claim 57, wherein said common polarizing element comprises a polarizer or a polarizing beam splitter.
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59. The apparatus of claim 58, further comprising a xenon and/or deuterium lamp supplying radiation.
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60. The apparatus of claim 28, wherein said focusing, collecting and dispersing are performed twice, once with polarization states of the sample beam and/or those of the modified and collected radiation within a first range of angles to a reference plane normal to a sample surface, and another time with said polarization states within a second different range of angles to the reference plane.
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61. The apparatus of claim 28, further comprising a polarizing element polarizing the sample beam before it reaches the sample, and/or analyzing the radiation modified by and collected from the sample to polarize the sample beam and/or the modified and collected radiation, and an instrument moving the element between at least two different positions where the focusing, collecting and dispersing are performed.
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62. The apparatus of claim 61, wherein said two different positions are substantially 90 degrees apart by rotation.
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63. A method for obtaining information of one or more layers of a sample, said method comprising:
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focusing a polarized first sample beam of broadband radiation onto the one or more layers, said beam having a multitude of polarization states;
collecting radiation that originates from the first beam and that is modified by the one or more layers of the sample by means of an objective;
analyzing and dispersing the radiation modified and collected from the sample to provide a polarimetric spectrum;
focusing a polarized second beam of radiation at said one or more layers in a direction at an oblique angle to the one or more layers;
obtaining measurements of changes in polarization state in amplitude and phase of the radiation that has been modified by the one or more layers and that originates from the second beam; and
determining information on optically detectable properties of said one or more layers from said measurements and the polarimetric spectrum. - View Dependent Claims (64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79)
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80. An apparatus for obtaining information of one or more layers of a sample, said apparatus comprising:
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first optics focusing a first polarized sample beam of broadband radiation to the one or more layers, and a second sample beam of polarized radiation at said one or more layers in a direction at an oblique angle to the one or more layers;
second optics collecting radiation that originates from the first beam and that is modified by the one or more layers of the sample, said second optics comprising an objective;
an instrument analyzing and dispersing the radiation modified and collected from the sample to provide a polarimetric spectrum; and
an ellipsometer obtaining measurements of changes in polarization state in amplitude and phase of the modified radiation from the one or more layers originating from second beam;
wherein information on optically detectable properties of said one or more layers is derivable from the measurements of the ellipsometer and the polarimetric spectrum. - View Dependent Claims (81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104)
a radiation source providing a beam of broadband radiation; and
third optics splitting said beam of broadband radiation into said polarized first beam and a reference beam, wherein said first optics focuses said first beam onto the one or more layers of the sample so that the focused beam has a multitude of polarization states.
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85. The apparatus of claim 84, wherein said third optics splits said beam from the source into a polarized sample beam and a polarized reference beam.
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86. The apparatus of claim 85, said third optics comprising a totally reflecting mirror placed less than completely across said beam.
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87. The apparatus of claim 85, said third optics deflecting a portion of said radiation in the beam from the source into a sample beam, the undeflected portion of the radiation defining a reference radiation beam.
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88. The apparatus of claim 85, wherein said third optics comprises a polarizing beam splitter.
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89. The apparatus of claim 85, wherein said third optics comprises a beam divider, said apparatus further comprising a polarizer.
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90. The apparatus of claim 89, said polarizer being in an optical path to the first optics and forms a part of the instrument.
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91. The apparatus of claim 89, said polarizer being in an optical path to the first optics, said instrument comprising an analyzer in an optical path from the second optics.
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92. The apparatus of claim 80, further comprising a detector detecting the reference beam to provide a reference spectrum, wherein said information is derivable by comparing said polarimetric spectrum and said reference spectrum.
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93. The apparatus of claim 92, said polarimetric and reference spectra comprising multiple wavelengths in a range from about 190 nm to about 830 nm.
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94. The apparatus of claim 80, said instrument comprising an analyzer, said apparatus further comprising a polarizer polarizing a beam of broadband radiation to generate the first polarized sample beam, wherein said analyzer and the polarizer do not rotate when radiation from the first and second beams is modified by the sample and collected, dispersed, analyzed and measured.
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95. The apparatus of claim 80, wherein said first optics focuses said polarized beam along different planes of incidence onto the sample.
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96. The apparatus of claim 80, wherein said first and second optics comprise a common objective that focuses the first beam onto and collects radiation modified by the one or more layers at the surface of the sample.
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97. The apparatus of claim 80, further comprising a flip-in polarizer and a mechanism moving the polarizer into and out of a path of a beam of broadband radiation from a radiation source to provide the first sample beam that is focused by the first optics.
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98. The apparatus of claim 97, wherein said polarizer polarizes the beam originating from the source to provide the first sample beam and analyses the radiation that is modified by the sample and collected by the second optics and that originates from the first beam.
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99. The apparatus of claim 80, said broadband radiation of the first and second beams comprising multiple wavelengths in a range from about 190 nm to about 830 nm.
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100. The apparatus of claim 80, wherein said instrument analyzes the radiation modified by the surface of the sample and from the first sample beam with respect to a predetermined and fixed polarization plane.
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101. The apparatus of claim 80, wherein said second beam is a laser beam whose wavelength is in the polarimetric spectrum, wherein the ellipsometer is a single wavelength ellipsometer that obtains measurements of changes in polarization state caused by the one or more layers at the wavelength of the laser, and wherein thickness information and refractive indices of the one or more layers are derivable over said polarimetric spectrum.
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102. The apparatus of claim 80, said second beam having wavelengths in a broadband, wherein the ellipsometer is a spectroscopic ellipsometer that obtains measurements of changes in polarization state caused by the one or more layers over the spectrum of the second beam, and said determining determines the refractive indices of the one or more layers over a combined spectrum of the first and second beams.
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103. The method of claim 102, said combined spectrum comprising multiple wavelengths ranging from about 190 nm to about 830 nm.
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104. The apparatus of claim 80, said first or second optics comprising a mirror having a coating that introduces a total change in phase of radiation reflected by it by the first and second optics of about π
- /2 radians.
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105. A method for measuring optically detectable properties of a sample, comprising:
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focusing a sample beam of radiation onto the sample, the radiation in said beam comprising at least one ultraviolet or deep ultraviolet wavelength;
collecting radiation modified by the sample;
dispersing the radiation modified by and collected from the sample to provide a spectrum, wherein no substantial relative change in polarization state between the radiation and the sample beam is caused by relative motion between optical elements employed in the focusing and collecting, wherein the radiation in the sample beam and/or the dispersed radiation is polarized; and
deriving information on optically detectable properties of the sample from said spectrum. - View Dependent Claims (106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117)
providing a reference beam;
detecting the reference beam to provide a reference spectrum; and
wherein said deriving comprises comparing said spectrum and said reference spectrum to obtain said information of the sample.
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107. The method of claim 105, wherein radiation in the sample beam and/or radiation that is dispersed is polarized.
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108. The method of claim 105, further comprising polarizing the sample beam before it reaches the sample, and analyzing the radiation modified by and collected from the sample, by a common polarizing element.
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109. The method of claim 108, wherein said polarizing and analyzing are performed by means of a polarizer or a polarizing beam splitter.
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110. The method of claim 105, further comprising polarizing a beam of broadband radiation to provide said sample beam, wherein said focusing focuses said polarized sample beam such that a beam having a multitude of polarization states is focused onto the sample, wherein said polarization states are functions of an angle φ
- to a reference plane normal to a sample surface, said angle φ
having a range defining a substantial angle of an illumination aperture.
- to a reference plane normal to a sample surface, said angle φ
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111. The method of claim 110, wherein said focusing focuses said polarized beam along different planes of incidence onto the sample, said planes being at different angles φ
- to the reference plane, the range of said angle of the illumination aperture being about 90 or 180 degrees.
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112. The method of claim 105, said focusing or collecting being performed at least twice and within at least two different ranges of angles to a reference plane normal to a sample surface.
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113. The method of claim 112, said sample having different optically detectable properties along at least two axes, wherein said focusing or collecting are repeated employing at least two different apertures each aligned or centered respectively about one of said axes.
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114. The method of claim 113, wherein said at least two different apertures are substantially 90 degrees apart.
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115. The method of claim 105, wherein said focusing, collecting, dispersing and deriving are performed twice, once with polarization states of the sample beam and/or those of the modified and collected radiation within a first range of angles to a reference plane normal to a sample surface, and another time with said polarization states within a second different range of angles to the reference plane.
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116. The method of claim 115, further comprising polarizing the sample beam before it reaches the sample, and/or analyzing the radiation modified by and collected from the sample with a polarizing element so that radiation of the sample beam and/or the modified and collected radiation is polarized, with the polarizing element in two different positions when the focusing, collecting, dispersing and deriving are performed twice.
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117. The method of claim 116, wherein said two different positions are substantially 90 degrees apart by rotation.
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118. A method for measuring optically detectable properties of a sample, comprising:
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focusing a sample beam of radiation onto the sample;
collecting radiation modified by the sample;
dispersing the radiation modified by and collected from the sample to provide a spectrum, wherein no substantial relative change in polarization state between the radiation and the sample beam is caused by relative motion between optical elements employed in the focusing, collecting and analyzing;
deriving information on optically detectable properties of the sample from said spectrum; and
polarizing the sample beam before it reaches the sample and/or analyzing the radiation modified by and collected from the sample, wherein said focusing, collecting, dispersing and deriving are performed twice, once with polarization states of the sample beam and/or those of the modified and collected radiation within a first range of angles to a reference plane normal to a sample surface, and another time with said polarization states within a second different range of angles to the reference plane. - View Dependent Claims (119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129)
providing a reference beam;
detecting the reference beam to provide a reference spectrum; and
wherein said deriving comprises comparing said spectrum and said reference spectrum to obtain said information of the sample.
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127. The method of claim 118, said focusing or collecting being performed twice and within two different ranges of angles to a reference plane normal to a sample surface.
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128. The method of claim 127, said sample having different optically detectable properties along at least two axes, wherein said focusing or collecting are performed twice employing at least two different apertures each aligned or centered respectively about one of said axes.
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129. The method of claim 128, wherein said at least two different apertures are substantially 90 degrees apart.
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130. A method for measuring optically detectable properties of a sample, comprising:
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focusing a sample beam of radiation onto the sample;
collecting radiation modified by the sample;
dispersing the radiation modified by and collected from the sample to provide a spectrum, wherein no substantial relative change in polarization state between the radiation and the sample beam is caused by relative motion between optical elements employed in the focusing, collecting and analyzing; and
deriving information on optically detectable properties of the sample from said spectrum;
said focusing or collecting being performed twice and within two different ranges of angles to a reference plane normal to a sample surface. - View Dependent Claims (131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142)
providing a reference beam;
detecting the reference beam to provide a reference spectrum; and
wherein said deriving comprises comparing said spectrum and said reference spectrum to obtain said information of the sample.
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143. An apparatus for measuring optically detectable properties of a sample, comprising:
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optics focusing a sample beam of radiation onto the sample, the radiation in said beam comprising at least one ultraviolet or deep ultraviolet wavelength;
a collector collecting radiation modified by the sample; and
a device dispersing the radiation modified by and collected from the sample to provide a spectrum, wherein no substantial relative change in polarization state between the radiation and the sample beam is caused by relative motion between optical elements employed in the focusing and collecting, wherein the radiation in the sample beam and/or the dispersed radiation is polarized;
wherein information on optically detectable properties of the sample is derivable from said spectrum. - View Dependent Claims (144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155)
a source providing a reference beam; and
a detector detecting the reference beam to provide a reference spectrum;
wherein said information on optically detectable properties of the sample is derivable by a comparison of said spectrum and said reference spectrum.
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145. The apparatus of claim 143, wherein the radiation in the sample beam and/or the dispersed radiation is polarized.
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146. The apparatus of claim 143, further comprising a common polarizing element polarizing the sample beam before it reaches the sample, and analyzing the radiation modified by and collected from the sample.
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147. The apparatus of claim 143, wherein said polarizing and analyzing are performed by means of a polarizer or a polarizing beam splitter.
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148. The apparatus of claim 143, further comprising a polarizing element polarizing a beam of broadband radiation to provide said sample beam, wherein said focusing focuses said polarized sample beam such that a beam having a multitude of polarization states is focused onto the sample, wherein said polarization states are functions of an angle φ
- to a reference plane normal to a sample surface, said angle φ
having a range defining a substantial angle of an illumination aperture.
- to a reference plane normal to a sample surface, said angle φ
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149. The apparatus of claim 148, wherein said optics focuses said polarized beam along different planes of incidence onto the sample, said planes being at different angles φ
- to the reference plane, the range of said angle of the illumination aperture being about 90 or 180 degrees.
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150. The apparatus of claim 143, further comprising at least two apertures, said sample having different optically detectable properties along at least two axes, wherein said focusing or collecting are repeated employing at least two different apertures each aligned or centered respectively about one of said axes.
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151. The apparatus of claim 150, wherein said at least two different apertures are substantially 90 degrees apart.
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152. The apparatus of claim 143, wherein said focusing, collecting and dispersing are performed twice, once with polarization states of the sample beam and/or those of the modified and collected radiation within a first range of angles to a reference plane normal to a sample surface, and another time with said polarization states within a second different range of angles to the reference plane.
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153. The apparatus of claim 143, further comprising a polarizing element polarizing the sample beam before it reaches the sample, and/or analyzing the radiation modified by and collected from the sample to polarize the sample beam and/or the modified and collected radiation, and an instrument moving the element between at least two different positions where the focusing, collecting and dispersing are performed.
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154. The apparatus of claim 153, wherein said two different positions are substantially 90 degrees apart by rotation.
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155. The apparatus of claim 143, further comprising a xenon and/or deuterium lamp supplying radiation for the sample beam.
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156. An apparatus for measuring optically detectable properties of a sample, comprising:
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optics focusing a sample beam of radiation onto the sample;
a collector collecting radiation modified by the sample;
a device dispersing the radiation modified by and collected from the sample to provide a spectrum, wherein no substantial relative change in polarization state between the radiation and the sample beam is caused by relative motion between optical elements employed in the focusing, collecting and analyzing, wherein information on optically detectable properties of the sample is derivable from the spectrum;
a polarizing element polarizing the sample beam before it reaches the sample and/or analyzing the radiation modified by and collected from the sample; and
an instrument moving the element between at least two positions where said focusing, collecting and dispersing are performed, so that polarization states of the sample beam and/or those of the modified and collected radiation have different ranges of angles to a reference plane normal to a sample surface when said element is at said at least two positions. - View Dependent Claims (157, 158, 159, 160, 161, 162, 163, 164, 165, 166)
a source providing a reference beam;
a detector detecting the reference beam to provide a reference spectrum; and
wherein said information is derivable by comparing said spectrum and said reference spectrum.
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164. The apparatus of claim 156, said focusing or collecting being performed twice and within two different ranges of angles to a reference plane normal to a sample surface.
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165. The apparatus of claim 164, further comprising at least two different apertures, said sample having different optically detectable properties along at least two axes, wherein said optics focuses or the collector collects radiation through the at least two different apertures each aligned or centered respectively about one of said axes.
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166. The apparatus of claim 165, wherein said at least two different apertures are substantially 90 degrees apart.
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167. An apparatus for measuring optically detectable properties of a sample, comprising:
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optics focusing a sample beam of radiation onto the sample;
a collector collecting radiation modified by the sample; and
a device dispersing the radiation modified by and collected from the sample to provide a spectrum, wherein no substantial relative change in polarization state between the radiation and the sample beam is caused by relative motion between optical elements employed in the focusing, collecting and analyzing, wherein said information is derivable from the spectrum, and wherein said optics focuses radiation or the collector collects radiation at at least two different times within two different ranges of angles to a reference plane normal to a sample surface. - View Dependent Claims (168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179)
a source providing a reference beam; and
a detector detecting the reference beam to provide a reference spectrum;
wherein information on optically detectable properties of the sample is derivable from said spectrum and said reference spectrum.
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179. The apparatus of claim 167, further comprising a xenon and/or deuterium lamp supplying radiation for the sample beam.
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180. A method for obtaining information of one or more layers of a sample, said method comprising:
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focusing a first sample beam onto the one or more layers, the radiation in said beam comprising at least one ultraviolet or deep ultraviolet wavelength;
collecting radiation that originates from the first beam and that is modified by the one or more layers of the sample;
dispersing the radiation modified and collected from the sample to provide a spectrum;
focusing a polarized second beam of radiation at said one or more layers in a direction at an oblique angle to the one or more layers;
obtaining measurements of changes in polarization state in amplitude and phase of the radiation that has been modified by the one or more layers and that originates from the second beam; and
deriving information on optically detectable properties of said one or more layers from said measurements and the spectrum. - View Dependent Claims (181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191)
providing a reference beam; and
detecting the reference beam to provide a reference spectrum;
wherein said information is derivable by comparing said spectrum and said reference spectrum.
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182. The method of claim 180, further comprising polarizing the first sample beam before it reaches the sample, and analyzing the radiation modified by and collected from the sample, by a common polarizing element.
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183. The method of claim 182, wherein said polarizing and analyzing are performed by means of a polarizer or a polarizing beam splitter.
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184. The method of claim 180, further comprising polarizing a beam of broadband radiation to provide said first sample beam, wherein said first sample beam focusing focuses said polarized first sample beam such that a beam having a multitude of polarization states is focused onto the sample, wherein said polarization states are functions of an angle φ
- to a reference plane normal to a sample surface, said angle φ
having a range defining a substantial angle of an illumination aperture.
- to a reference plane normal to a sample surface, said angle φ
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185. The method of claim 184, wherein said first sample beam focusing focuses said polarized beam along different planes of incidence onto the sample, said planes being at different angles φ
- to the reference plane, the range of said angle of the illumination aperture being about 90 or 180 degrees.
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186. The method of claim 180, said first sample beam focusing or collecting being performed at least twice and within at least two different ranges of angles to a reference plane normal to a sample surface.
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187. The method of claim 181, said sample having different optically detectable properties along at least two axes, wherein said first sample beam focusing or collecting are repeated employing at least two different apertures each aligned or centered respectively about one of said axes.
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188. The method of claim 187, wherein said at least two different apertures are substantially 90 degrees apart.
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189. The method of claim 180, wherein said first sample beam focusing, collecting, dispersing and deriving are performed twice, once with polarization states of the first sample beam and/or those of the modified and collected radiation within a first range of angles to a reference plane normal to a sample surface, and another time with said polarization states within a second different range of angles to the reference plane.
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190. The method of claim 189, further comprising polarizing the first sample beam before it reaches the sample, and/or analyzing the radiation modified by and collected from the sample with a polarizing element so that radiation of the first sample beam and/or the modified and collected radiation is polarized, with the polarizing element in two different positions when the focusing, collecting, dispersing and deriving are performed twice.
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191. The method of claim 190, wherein said two different positions are substantially 90 degrees apart by rotation.
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192. A method for obtaining information of one or more layers of a sample, said method comprising:
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focusing a first sample beam of radiation onto the one or more layers;
collecting radiation that originates from the first beam and that is modified by the one or more layers of the sample;
dispersing the radiation modified and collected from the sample to provide a spectrum;
focusing a polarized second beam of radiation at said one or more layers in a direction at an oblique angle to the one or more layers;
obtaining measurements of changes in polarization state in amplitude and phase of the radiation that has been modified by the one or more layers and that originates from the second beam;
deriving information on optically detectable properties of said one or more layers from said measurements and the spectrum; and
polarizing the first sample beam before it reaches the sample and/or analyzing the radiation modified by and collected from the sample, wherein said first sample beam focusing, collecting, dispersing and deriving are performed twice, once with polarization states of the first sample beam and/or those of the modified and collected radiation within a first range of angles to a reference plane normal to a sample surface, and another time with said polarization states within a second different range of angles to the reference plane. - View Dependent Claims (193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203)
providing a reference beam;
detecting the reference beam to provide a reference spectrum; and
wherein said deriving comprises comparing said spectrum and said reference spectrum.
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201. The method of claim 192, said first sample beam focusing or collecting being performed twice and within two different ranges of angles to a reference plane normal to a sample surface.
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202. The method of claim 201, said sample having different optically detectable properties along at least two axes, wherein said first sample beam focusing or collecting are performed twice employing at least two different apertures each aligned or centered respectively about one of said axes.
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203. The method of claim 202, wherein said at least two different apertures are substantially 90 degrees apart.
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204. A method for obtaining information of one or more layers of a sample, said method comprising:
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focusing a first sample beam of radiation onto the one or more layers;
collecting radiation that originates from the first beam and that is modified by the one or more layers of the sample;
dispersing the radiation modified and collected from the sample to provide a spectrum;
focusing a polarized second beam of radiation at said one or more layers in a direction at an oblique angle to the one or more layers;
obtaining measurements of changes in polarization state in amplitude and phase of the radiation that has been modified by the one or more layers and that originates from the second beam; and
deriving information on optically detectable properties of said one or more layers from said measurements and the spectrum;
said first sample beam focusing or collecting being performed twice and within two different ranges of angles to a reference plane normal to a sample surface. - View Dependent Claims (205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215)
providing a reference beam;
detecting the reference beam to provide a reference spectrum; and
wherein said deriving comprises comparing said spectrum and said reference spectrum to obtain said information of the sample.
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216. An apparatus for obtaining information of one or more layers of a sample, said apparatus comprising:
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optics focusing a first sample beam of radiation to the one or more layers, and a second sample beam of polarized radiation at said one or more layers in a direction at an oblique angle to the one or more layers, the radiation in said first beam comprising at least one ultraviolet or deep ultraviolet wavelength;
a collector collecting radiation that originates from the first beam and that is modified by the one or more layers of the sample;
a device dispersing the radiation modified and collected from the sample to provide a spectrum; and
an ellipsometer obtaining measurements of changes in polarization state in amplitude and phase of the modified radiation from the one or more layers originating from second beam;
wherein said information on optically detectable properties of said one or more layers is derivable from the measurements of the ellipsometer and the spectrum. - View Dependent Claims (217, 218, 219, 220, 221, 222, 223, 224, 225, 226)
a source providing a reference beam;
a detector detecting the reference beam to provide a reference spectrum; and
wherein said information is derivable by a comparison of said spectrum and said reference spectrum.
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218. The apparatus of claim 216, further comprising a common polarizing element polarizing the first sample beam before it reaches the sample, and analyzing the radiation modified by and collected from the sample.
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219. The apparatus of claim 218, wherein said polarizing and analyzing are performed by means of a polarizer or a polarizing beam splitter.
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220. The apparatus of claim 216, further comprising a polarizing element polarizing a beam of broadband radiation to provide said first sample beam, wherein said optics focuses said polarized first sample beam such that a beam having a multitude of polarization states is focused onto the sample, wherein said polarization states are functions of an angle φ
- to a reference plane normal to a sample surface, said angle φ
having a range defining a substantial angle of an illumination aperture.
- to a reference plane normal to a sample surface, said angle φ
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221. The apparatus of claim 220, wherein said optics focuses said polarized first sample beam along different planes of incidence onto the sample, said planes being at different angles φ
- to the reference plane, the range of said angle of the illumination aperture being about 90 or 180 degrees.
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222. The apparatus of claim 216, further comprising at least two apertures, said sample having different optically detectable properties along at least two axes, wherein said first sample beam focusing or collecting are repeated employing at least two different apertures each aligned or centered respectively about one of said axes.
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223. The apparatus of claim 222, wherein said at least two different apertures are substantially 90 degrees apart.
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224. The apparatus of claim 216, wherein said first sample beam focusing, collecting, dispersing and deriving are performed twice, once with polarization states of the first sample beam and/or those of the modified and collected radiation within a first range of angles to a reference plane normal to a sample surface, and another time with said polarization states within a second different range of angles to the reference plane.
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225. The apparatus of claim 216, further comprising a polarizing element polarizing the first sample beam before it reaches the sample, and/or analyzing the radiation modified by and collected from the sample to polarize the first sample beam and/or the modified and collected radiation, and an instrument moving the element between at least two different positions where the focusing, collecting and dispersing are performed.
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226. The apparatus of claim 225, wherein said two different positions are substantially 90 degrees apart by rotation.
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227. An apparatus for obtaining information of one or more layers of a sample, said apparatus comprising:
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optics focusing a first sample beam of radiation to the one or more layers, and a second sample beam of polarized radiation at said one or more layers in a direction at an oblique angle to the one or more layers, the radiation in said first beam comprising at least one ultraviolet or deep ultraviolet wavelength;
a collector collecting radiation that originates from the first beam and that is modified by the one or more layers of the sample;
a device dispersing the radiation modified and collected from the sample to provide a spectrum;
a polarizing element polarizing the first sample beam before it reaches the sample and/or analyzing the radiation modified by and collected from the sample before such radiation is dispersed by the device;
an ellipsometer obtaining measurements of changes in polarization state in amplitude and phase of the modified radiation from the one or more layers originating from second beam;
wherein said information on optically detectable properties of said one or more layers is derivable from measurements of the ellipsometer and the spectrum; and
an instrument moving the element between at least two positions, so that polarization states of the first sample beam and/or those of the modified and collected radiation have different ranges of angles to a reference plane normal to a sample surface when said element is at said at least two positions. - View Dependent Claims (228, 229, 230, 231, 232, 233, 234, 235, 236, 237)
a source providing a reference beam;
a detector detecting the reference beam to provide a reference spectrum; and
wherein information on optically detectable properties of the sample by a comparison of said spectrum and said reference spectrum.
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235. The apparatus of claim 227, said focusing or collecting being performed twice and within two different ranges of angles to a reference plane normal to a sample surface.
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236. The apparatus of claim 235, further comprising at least two different apertures, said sample having different optically detectable properties along at least two axes, wherein said optics focuses or the collector collects radiation through the at least two different apertures each aligned or centered respectively about one of said axes.
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237. The apparatus of claim 236, wherein said at least two different apertures are substantially 90 degrees apart.
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238. An apparatus for obtaining information of one or more layers of a sample, said apparatus comprising:
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optics focusing a first sample beam of radiation to the one or more layers, and a second sample beam of polarized radiation at said one or more layers in a direction at an oblique angle to the one or more layers, the radiation in said first beam comprising at least one ultraviolet or deep ultraviolet wavelength;
a collector collecting radiation that originates from the first beam and that is modified by the one or more layers of the sample;
a device analyzing and dispersing the radiation modified and collected from the sample to provide a spectrum; and
an ellipsometer obtaining measurements of changes in polarization state in amplitude and phase of the modified radiation from the one or more layers originating from second beam;
wherein said information on optically detectable properties of said one or more layers from the measurements of the ellipsometer and the spectrum, and wherein said optics focuses radiation in the first sample beam or the collector collects radiation at at least two different times within two different ranges of angles to a reference plane normal to a sample surface. - View Dependent Claims (239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249)
a source providing a reference beam;
a detector detecting the reference beam to provide a reference spectrum; and
information on optically detectable properties of the sample is derivable from a comparison of said spectrum and said reference spectrum.
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249. The apparatus of claim 238, further comprising a xenon and/or deuterium lamp supplying radiation for the first sample beam.
Specification