Spectroscopic scatterometer system

• US 6,483,580 B1
• Filed: 03/06/1998
• Issued: 11/19/2002
• Est. Priority Date: 03/06/1998
• Status: Expired due to Term

• Current Assignee: Kla-Tencor Technologies Corporation (KLA Corporation)
• Original Assignee: Kla-Tencor Technologies Corporation (KLA Corporation)
• Inventors: Xu, Yiping, Abdulhalim, Ibrahim
• Primary Examiner(s): Font, Frank G.
• Assistant Examiner(s): Nguyen, Tu T
• Application Number:
  US09/036,557
• Time in Patent Office: 1,719 Days
• Field of Search: 356/364, 356/365, 356/366, 356/367, 356/369, 356/319, 356/328, 356/73, 356/630, 356/300, 356/446, 356/447, 356/448, 356/326, 356/445
• US Class Current: 356/300
• CPC Class Codes: G01B 11/0641 with measurement of polarization
• CPC Class Codes: G01N 2021/213 Spectrometric ellipsometry
• CPC Class Codes: G01N 2021/556 Measuring separately scattering and specular
• CPC Class Codes: G01N 2021/95615 with stored comparision signal
• CPC Class Codes: G01N 21/211 Ellipsometry optical thickness measurement G01B11/06
• CPC Class Codes: G01N 21/4788 Diffraction for sizing particles G01N15/0205
• CPC Class Codes: G01N 21/55 Specular reflectivity
• CPC Class Codes: G01N 21/9501 Semiconductor wafers manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10
• CPC Class Codes: G01N 21/956 Inspecting patterns on the surface of objects contactless testing of electronic circuits G01R31/308; testing currency G07D; manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10
• CPC Class Codes: G01N 21/95607 using a comparative method
• CPC Class Codes: G03F 7/70491 Information management, e.g. software; Active and passive control, e.g. details of controlling exposure processes or exposure tool monitoring processes
• CPC Class Codes: G03F 7/70616 Monitoring the printed patterns
• CPC Class Codes: G03F 7/70625 Dimensions, e.g. line width, critical dimension [CD], profile, sidewall angle or edge roughness
• CPC Class Codes: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

Before the diffraction from a diffracting structure on a semiconductor wafer is measured, where necessary, the film thickness and index of refraction of the films underneath the structure are first measured using spectroscopic reflectometry or spectroscopic ellipsometry. A rigorous model is then used to calculate intensity or ellipsometric signatures of the diffracting structure. The diffracting structure is then measured using a spectroscopic scatterometer using polarized and broadband radiation to obtain an intensity or ellipsometric signature of the diffracting structure. Such signature is then matched with the signatures in the database to determine the grating shape parameters of the structure.

Claims

1. A method for measuring one or more parameters of a periodic diffracting structure adjacent to an associated structure, said associated structure having a thickness and an optical index, comprising:

providing an optical index and a film thickness of the associated structure;

constructing a reference database of one or more parameters related to said diffracting structure using said optical index and film thickness of the associated structure;

directing a beam of electromagnetic radiation at a plurality of wavelengths at said periodic diffracting structure,

detecting intensity data or ellipsometric parameters of a diffraction at said plurality of wavelengths from said diffracting structure of said beam; and

comparing said detected intensity data or ellipsometric parameters to said database to determine said one or more parameters.

2. The method of claim 1, wherein said directing directs said beam at an oblique angle to the diffracting structure.

3. The method of claim 2, wherein said oblique angle is in the range of about 40 to 80 degrees to a normal direction to the structure.

4. The method of claim 2, wherein said detecting detects a zeroth order diffraction of said beam from said diffracting structure.

5. The method of claim 2, wherein said directing directs polarized radiation to the diffracting structure.

6. The method of claim 1, wherein said detecting detects a zeroth order diffraction of said beam from said diffracting structure.

7. The method of claim 6, wherein said directing directs polarized radiation to the diffracting structure.

8. The method of claim 1, wherein said constructing constructs a reference database comprising a plurality of functions, each of said functions corresponding to one or more parameters of said diffracting structure and providing values of intensity or an ellipsometric parameter at said plurality of wavelengths.

9. The method of claim 8, each of said functions corresponding to a probable shape of lines, linewidth, height or wall angle of said diffracting structure.

10. The method of claim 1, wherein said directing directs polarized radiation to the diffracting structure.

11. The method of claim 1, wherein said constructing constructs said database by means of a model without the use of reference samples.

12. The method of claim 1, said plurality of wavelengths comprising ultraviolet wavelengths.

13. The method of claim 1, wherein said constructing constructs a reference database over a spectrum of wavelengths, said directing directs a beam of broadband radiation at wavelengths comprising said spectrum and said detecting detects intensity or ellipsometric parameter data over said spectrum of wavelengths.

14. The method of claim 13, wherein said comparing compares intensity data at wavelengths in a selected portion of the spectrum to a portion of the database.

15. The method of claim 14, said spectrum comprising ultraviolet wavelengths, wherein said portion consists of wavelengths in the ultraviolet range.

16. The method of claim 1, wherein said providing comprises measuring an optical index and film thickness of the associated structure.

17. The method of claim 16, wherein said measuring measures by means of a spectroscopic ellipsometer, a spectrophotometer or a spectroreflectometer.

18. The method of claim 1, said one or more parameters comprising shape of lines, linewidth, pitch, height and/or side wall angle of the structure.

19. The method of claim 1, wherein said detecting detects at said plurality of wavelengths substantially simultaneously.

20. The method of claim 1, further comprising using the one or more parameters of the diffracting structure in wafer process monitoring, closed-loop control or focus-exposure control in photolithography.

86. The method of claim 5, said oblique angle being substantially the Brewster angle for silicon.

132. The apparatus of claim 2, wherein said focusing and pattern recognition device supplies focus information to a stage for adjusting height of the structure so that it is in proper focus of the optics.

21. An apparatus for measuring one or more parameters of a periodic diffracting structure adjacent to at least one associated structure, said associated structure having a film thickness and an optical index, comprising:

a computer constructing a reference database of one or more parameters related to said diffracting structure using said an optical index and a film thickness of the associated structure;

optics directing a beam of electromagnetic radiation at a plurality of wavelengths at said periodic diffracting structure,

a detector detecting intensity data or ellipsometric parameters of a diffraction at said plurality of wavelengths from said diffracting structure; and

a processor comparing said detected intensity data or ellipsometric parameters to said database to determine said one or more parameters.

22. The apparatus of claim 21, wherein said optics directs said beam at an oblique angle to the diffracting structure.

23. The method of claim 22, wherein said oblique angle is in the range of about 40 to 80 degrees.

24. The apparatus of claim 22, wherein said detector detects a zeroth order diffraction of said beam from said diffracting structure.

25. The apparatus of claim 22, wherein said optics directs polarized radiation to the diffracting structure.

26. The apparatus of claim 21, wherein said detector detects a zeroth order diffraction of said beam from said diffracting structure.

27. The apparatus of claim 26, wherein said optics comprises a polarizer.

28. The apparatus of claim 27, wherein said polarizer is substantially fixed in position.

29. The apparatus of claim 21, wherein said computer constructs a reference database comprising a plurality of functions, each of said functions corresponding to one or more parameters of said diffracting structure and providing values of intensity at said plurality of wavelengths.

30. The apparatus of claim 29, each of said functions corresponding to a probable shape of lines, linewidth, height or wall angle of said diffracting structure.

31. The apparatus of claim 21, wherein said optics directs polarized radiation to the diffracting structure.

32. The apparatus of claim 21, wherein said computer constructs said database by means of a model without the use of reference samples.

33. The apparatus of claim 21, said plurality of wavelengths comprising ultraviolet wavelengths.

34. The apparatus of claim 21, wherein said computer constructs a reference database over a spectrum of wavelengths, said optics directing a beam of broadband radiation at wavelengths comprising said spectrum and said detector detects intensity data over said spectrum of wavelengths.

35. The apparatus of claim 34, wherein said processor compares intensity or ellipsometric parameter data at wavelengths in a selected portion of the spectrum to a portion of the database.

36. The apparatus of claim 35, said spectrum comprising ultraviolet wavelengths, wherein said portion consists of wavelengths in the ultraviolet range.

37. The apparatus of claim 21, further comprising an instrument measuring said optical index and film thickness of the associated structure.

38. The apparatus of claim 37, wherein said instrument comprises a spectroscopic ellipsometer, spectrophotometer or spectroreflectometer.

39. The apparatus of claim 37, wherein said instrument and optics employ common optical elements, said common elements comprising a broadband radiation source, a polarizer and a spectrometer.

40. The apparatus of claim 37, wherein said instrument and optics employ common optical elements, said common elements comprising also an analyzer, wherein said polarizer and analyzer are set to provide and pass radiation of substantially the same polarization when intensity data is detected from said diffracting structure, and to cause rotation between the polarizer and the analyzer when ellipsometric parameters are detected from the structure.

41. The apparatus of claim 21, said one or more parameters comprising shape of lines, linewidth, pitch, height and/or side wall angle of the structure.

42. The apparatus of claim 21, said optics comprising an optical fiber.

43. The apparatus of claim 21, further comprising a focusing and pattern recognition device for sensing whether at least one of the structures is in proper focus of the optics.

44. The apparatus of claim 43, wherein said focusing and pattern recognition device supplies focus information to a stage for adjusting height of the at least one of the structures so that it is in proper focus of the optics.

45. The apparatus of claim 21, wherein said apparatus comprises at least two of the following:

a spectroscopic ellipsometer, a spectroscopic scatterometer and a spectroreflectometer.

46. The apparatus of claim 21, said apparatus comprising a spectroscopic scatterometer, and a spectroscopic ellipsometer and/or a spectroreflectometer.

47. A method for measuring one or more parameters of a periodic diffracting structure of a sample, said one or more parameters comprising shape of lines, linewidth, pitch, height and/or side wall angle of the structure, said method comprising:

providing broadband radiation;

polarizing the broadband radiation to produce a sampling beam;

directing the sampling beam towards the structure at an oblique angle to the sample;

detecting intensity data of radiation of the sampling beam that has been diffracted from the periodic diffracting structure over a range of wavelengths; and

comparing the detected radiation intensity data to a reference database to determine said shape of lines, linewidth, pitch, height and/or side wall angle of the structure.

48. The method of claim 47, said sample having an associated structure, said diffracting structure lying adjacent to said associated structure of the sample, said method further comprising:

providing an optical index and film thickness of the associated structure; and

constructing the reference database using said optical index and film thickness of the associated structure, wherein the database is related to the one or more parameters.

49. The method of claim 48, wherein said constructing constructs the reference database over a spectrum of wavelengths, said directing directs a beam of radiation having wavelengths that comprise said spectrum and said detecting detects intensity data at a plurality of wavelengths over said spectrum of wavelengths.

50. The method of claim 49, wherein said comparing compares intensity data at wavelengths in a selected portion of the spectrum to a portion of the database.

51. The method of claim 50, said spectrum comprising ultraviolet wavelengths, wherein said portion consists of wavelengths in the ultraviolet range.

52. The method of claim 47, wherein said polarizing polarizes the broadband radiation so that the sampling beam is in the TE or TM mode, and the detecting detects radiation in the TE or TM mode.

53. The method of claim 47, wherein said detecting detects a zeroth order diffraction of said beam from said diffracting structure.

54. The method of claim 47, wherein said polarizing produces a sampling beam in the TE or TM mode.

55. The method of claim 47, wherein said polarizing polarizes the broadband radiation so that a sampling being with a predetermined polarization mode is produced.

56. The method of claim 47, wherein said oblique angle is in the range of about 40 to 80 degrees.

57. The method of claim 47, wherein said detecting detects a zeroth order diffraction of said beam from said diffracting structure.

58. The method of claim 47, wherein said comparing comprises constructing a reference database comprising a plurality of functions, each of said functions corresponding to one or more parameters of said diffracting structure and providing values of intensity at said plurality of wavelengths.

59. The method of claim 58, each of said functions corresponding to a probable shape of lines, linewidth, height or side wall angle of said diffracting structure.

60. The method of claim 47, wherein said comparing comprises constructing said database by means of a model without the use of reference samples.

61. The method of claim 47, further comprising performing spectroscopic measurements of data related to film thickness and index of refraction information of the sample over a spectrum.

62. The method of claim 47, said diffracting structure located adjacent to an associated structure, said method further comprising performing spectroscopic measurements of data related to characteristics of the associated structure.

63. The method of claim 62, wherein said spectroscopic measurements measures data related to film thickness and index of refraction information of the associated structure over a spectrum.

64. The method of claim 62, wherein the performing performs the measurements by means of a spectroscopic ellipsometer, spectrophotometer or spectroreflectometer.

65. The method of claim 47, wherein said detecting detects at a plurality of wavelengths substantially simultaneously.

66. The method of claim 47, further comprising using the shape of lines, linewidth, pitch, height and/or side wall angle of the diffracting structure in wafer process monitoring closed-loop control or focus-exposure control in photolithography.

67. A method for measuring one or more parameters of a periodic diffracting structure adjacent to an associated structure of a sample, comprising:

performing spectroscopic measurements on the associated structure to determine its characteristics;

constructing a reference database of one or more parameters related to said diffracting structure using said characteristics of the associated structure;

performing scatterometric measurements on the periodic diffracting structures to obtain intensity or ellipsometric data; and

comparing said intensity or ellipsometric data to-the reference database to derive said one or more parameters.

68. The method of claim 67, wherein said characteristics of the associated structure comprises optical index and film thickness.

69. The method of claim 68, wherein said spectroscopic measurements performing performs spectroscopic ellipsometric or spectroscopic reflectometric measurements.

70. The method of claim 68, wherein said spectroscopic measurements and scatterometric measurements are performed using broadband radiation.

71. The method of claim 68, wherein said spectroscopic measurements and scatterometric measurements are performed using polarized radiation.

72. The method of claim 68, wherein said constructing constructs a reference database over a spectrum of wavelengths, and wherein said scatterometric measurements are performed over said spectrum of wavelengths to obtain intensity data over said spectrum.

73. The method of claim 72, wherein said comparing compares intensity data at wavelengths in a selected portion of the spectrum to a portion of the database.

74. The method of claim 73, said spectrum comprising ultraviolet wavelengths, wherein said portion consists of wavelengths in the ultraviolet range.

75. The method of claim 67, said one or more parameters comprising shape of lines, linewidth, pitch, height and/or side wall angle of the structure.

76. The method of claim 67, wherein the performances of said spectroscopic and scatterometric measurements comprise detecting at a plurality of wavelengths substantially simultaneously.

77. An apparatus for measuring one or more parameters of a periodic diffracting structure adjacent to at least one associated structure, said associated structure having a film Thickness and an optical index, comprising:

means for constructing a reference database of one or more parameters related to said diffracting structure using said an optical index and a film thickness of the associated structure;

means for directing a beam of electromagnetic radiation at a plurality of wavelengths at said periodic diffracting structure;

means for detecting intensity data of a diffraction at said plurality of wavelengths from said diffracting structure; and

means for comparing said detected intensity data to said database to determine said one or more parameters.

78. The apparatus of claim 77, said one or more parameters comprising shape of lines, linewidth, pitch, height and/or side wall angle of the structure.

79. An apparatus for measuring one or more parameters of a periodic diffracting structure adjacent to at least one associated structure, said associated structure having a film thickness and an optical index, comprising:

means for constructing a reference database of one or more parameters related to said diffracting structure using said an optical index and a film thickness of the associated structure;

means for directing a beam of electromagnetic radiation at a plurality of wavelengths at said periodic diffracting structure;

means for detecting ellipsometric parameters of a diffraction at said plurality of wavelengths from said diffracting structure; and

means for comparing said detected ellipsometric parameters to said database to determine said one or more parameters.

80. The apparatus of claim 79, said one or more parameters comprising it shape of lines, linewidth, pitch, height and/or side wall angle of the structure.

81. A method for measuring one or more parameters of a sample having a periodic diffracting structure and a film structure associated with the diffracting structure, comprising

performing spectroscopic measurements on the sample to determine at least film thickness or index of refraction information of the associated structure;

constructing a reference database of one or more parameters related to said diffracting structure using said film thickness or index of refraction information of the associated structure; and

performing scatterometric measurements on the diffracting structure to obtain intensity or ellipsometric data.

82. The method of claim 81, further comprising:

comparing said intensity or cllipsometric data to the reference database to derive said one or more parameters.

83. The method of claim 81, said spectroscopic measurements performed being ellipsometric measurements.

84. The method of claim 81, wherein said spectroscopic and scatterometric measurements are performed using common optical elements.

85. The method of claim 81, wherein said spectroscopic and scatterometric measurements are performed by supplying a beam of radiation illuminating the sample at an oblique angle in the range of 40 to 90 degrees to a normal direction to the sample.

87. The method of claim 81, further comprising a focusing radiation to the sample and detecting whether the sample is at a proper height.

88. The method of claim 81, further comprising adjusting height of the sample in response to the detection.

89. The method of claim 81, further comprising comparing a reflected image of a portion of the sample to a pattern.

90. The method of claim 81, further comprising detecting radiation reflected by the sample by means of a reflectometer.

91. The method of claim 81, further comprising causing relative motion between the sample and instrument(s) used to perform the spectroscopic and/or scatterometric measurements, so that the spectroscopic measurement-measures an area of the sample without diffracting structures, and the scatterometric measurement measures a diffracting structure of the sample.

92. The method of claim 81, wherein said sample comprises a plurality of periodic diffracting structures and a substrate comprising one or more layers associated with the structures, wherein said spectroscopic measurements measures film thickness or index of refraction information of said one or more layers only once, and wherein said scatterometric measurements measure each of the structures to obtain data.

93. The method of claim 81, further comprising deriving physical parameters related to the sample from the film thickness and/or index of refraction information of the sample and the intensity or ellipsometric data.

94. The method of claim 93, wherein said deriving derives one or more parameters of the diffracting structure, said parameters comprising shape of lines, critical dimension, height and sidewall angle.

95. The method of claim 94, wherein said sample comprises a plurality of periodic diffracting structures associated with a substrate comprising one or more layers, each structure associated with a set of the one or more parameters, wherein the spectroscopic measurements determine film thickness or index of refraction information of the one or more layers, said deriving comprising constructing a database using said information, and wherein said deriving derives the sets of parameters of the plurality of periodic diffracting structures using the database.

96. The method of claim 94, wherein each of a plurality of samples comprises a substrate where the substrates of said plurality of samples have similar thickness and index of refraction characteristics, the structure of each sample associated with a set of the one or more parameters, wherein the spectroscopic measurements determine film thickness or index of refraction information of only one of the samples, said deriving comprising constructing a database using said information of said only one sample, and wherein said deriving derives the sets of parameters of the periodic diffracting structures of the plurality of samples using the database.

97. The method of claim 81, wherein said spectroscopic measurements are performed on the sample to determine at least film thickness and index of refraction information of the sample.

98. The method of claim 81, said one or more parameters comprising shape of lines, linewidth, pitch, height and/or side wall angle of the structure.

99. The method of claim 81, wherein the performances of said spectroscopic and scatterometric measurements comprise detecting at a plurality of wavelengths substantially simultaneously.

100. The method of claim 81, further comprising using the intensity or ellipsometric data of the diffracting structure in wafer process monitoring, closed-loop control or focus-exposure control in photolithography.

101. A method for measuring one or more parameters of a periodic diffracting structure of a sample, said one or more parameters comprising shape of lines, linewidth, pitch, height and/or side wall angle of the structure, said method comprising:

providing a reference database;

providing broadband radiation;

polarizing the broadband radiation to produce a sampling beam;

directing the sampling beam towards the periodic diffracting structure;

detecting ellipsometric parameters of radiation of the sampling beam that has been diffracted from the structure over a range of wavelengths; and

comparing the detected radiation to the reference database to determine said shape of lines, linewidth, pitch, height and/or side wall angle of the structure.

102. The method of claim 101, said sample having an associated structure, said diffracting structure lying adjacent to said associated structure of the sample, said method further comprising:

providing an optical index and film thickness of the associated structure; and

constructing the reference database using said optical index and film thickness of the associated structure, wherein the reference database is related to the one or more parameters.

103. The method of claim 102, wherein said constructing constructs a reference database of parameters over a spectrum of wavelengths, and said directing directs a beam of radiation having wavelengths that comprise said spectrum and said detecting detects ellipsometric parameters at a plurality of wavelengths over said spectrum of wavelengths.

104. The method of claim 103, wherein said comparing compares ellipsometric parameters at wavelengths in a selected portion of the spectrum to a portion of the database.

105. The method of claim 104, said spectrum comprising ultraviolet wavelengths, wherein said portion consists of wavelengths in the ultraviolet range.

106. The method of claim 101, further comprising directing said sampling beam at an oblique angle to the diffracting structure.

107. The method of claim 101, wherein said detecting detects a zeroth order diffraction of said beam from said diffracting structure.

108. The method of claim 101, wherein said polarizing produces a sampling beam in the TE or TM mode.

109. The method of claim 101, wherein said detecting detects at a plurality of wavelengths substantially simultaneously.

110. The method of claim 101, Other comprising using the shape of lines, linewidth, pitch, height and/or side wall angle of the diffracting structure in wafer process monitoring, closed-loop control or focus-exposure control in photolithography.

111. An apparatus for measuring one or more parameters of a periodic diffracting structure of a sample, said one or more parameters comprising shape of lines, linewidth, pitch, height and/or side wall angle of the structure, said apparatus comprising.

a reference database;

optics providing a sampling beam of polarized broadband radiation and directing the beam towards the structure at an oblique angle to the sample;

a detector detecting intensity data of radiation of the sampling beam that has been diffracted from the periodic diffracting structure over a range of wavelengths; and

a processor comparing the detected radiation intensity data to a reference database to determine said shape of lines, linewidth, pitch, height and/or side wall angle of the structure.

112. The apparatus of claim 111, said sample having an associated structure, said diffracting structure located adjacent to said associated structure of the sample, wherein said processor constructs a reference database using optical index and film thickness of the associated structure, wherein the database is related to the one or more parameters.

113. The apparatus of claim 112, wherein said processor constructs the reference database over a spectrum of wavelengths, said optics provides radiation having wavelengths that comprise said spectrum and said detector detects intensity data at a plurality of wavelengths over said spectrum of wavelengths.

114. The apparatus of claim 113, wherein said processor compares intensity data only at wavelengths in a selected portion of the spectrum to a portion of the database.

115. The apparatus of claim 114, said spectrum comprising ultraviolet wavelengths, wherein said portion consists of wavelengths in the ultraviolet range.

116. The apparatus of claim 111, wherein said optical element polarizes the broadband radiation so that the sampling beam is in the TE or TM mode, and the detector detects radiation in the TE or TM mode.

117. The apparatus of claim 111, wherein said detector detects a zeroth order diffraction of said beam from said diffracting structure.

118. The apparatus of claim 111, wherein said optics produces a sampling beam in the TE or TM mode.

119. The apparatus of claim 111, wherein said oblique angle is in the range of about 40 to 80 degrees.

120. The apparatus of claim 111, wherein said detector detects a zeroth order diffraction of said beam from said diffracting structure.

121. The apparatus of claim 111, wherein said processor constructs a reference database comprising a plurality of functions, each of said functions corresponding to one or more parameters of said diffracting structure and providing values of intensity at said plurality of wavelengths.

122. The apparatus of claim 121, each of said functions corresponding to a probable shape of lines, linewidth, height or side wall angle of said diffracting structure.

123. The apparatus of claim 111, wherein said processor constructs said database by means of a model without the use of reference samples.

124. The apparatus of claim 111, further comprising a spectroscopic device measuring data related to film thickness and index of refraction information of the sample over a spectrum.

125. The apparatus of claim 111, said diffracting structure located adjacent to an associated structure, said apparatus further comprising a spectroscopic device measuring data related to characteristics of the associated structure.

126. The apparatus of claim 125, said spectroscopic device measuring data related to film thickness and index of refraction information of the associated structure over a spectrum.

127. The apparatus of claim 125, wherein said instrument comprises a spectroscopic ellipsometer, spectrophotometer or spectroreflectometer.

128. The apparatus of claim 125, wherein said instrument and optics employ common optical elements, said common elements comprising a broadband radiation source, a polarizer and a spectrometer.

129. The apparatus of claim 125, wherein said instrument and optics employ common optical elements, said common elements comprising also an analyzer, wherein said polarizer and analyzer are set to provide and pass radiation of substantially the same polarization when intensity data is detected from said diffracting structure, and to cause rotation between the polarizer and the analyzer when ellipsometric parameters are detected from the structure.

130. The apparatus of claim 111, said optics comprising an optical fiber.

131. The apparatus of claim 111, further comprising a focusing and pattern recognition device sensing whether the structure is in proper focus of the optics.

133. The apparatus of claim 111, wherein said apparatus comprises at least two of the following:

a spectroscopic ellipsometer, a spectroscopic scatterometer and a spectroreflectometer.

134. The apparatus of claim 111, said apparatus comprising a spectroscopic scatterometer, and a spectroscopic ellipsometer and/or a spectroreflectometer.

135. An apparatus for measuring one or more parameters of a periodic diffracting structure of a sample, said one or more parameters comprising shape of lines, linewidth, pitch, height and/or side wall angle of the structure, said apparatus comprising:

a reference database;

optics providing a sampling beam of polarized broadband radiation and directing the beam towards the structure at an oblique angle to the sample;

a detector detecting ellipsometric parameters of radiation of the sampling beam that has been diffracted from the periodic diffracting structure over a range of wavelengths; and

a processor comparing the detected ellipsometric parameters to a reference database to determine said shape of lines, linewidth, pitch, height and/or side wall angle of the structure.

136. The apparatus of claim 135, said sample having an associated structure, said diffracting structure located adjacent to said associated structure of the sample, wherein said processor constructs a reference database using optical index and film thickness of the associated structure, wherein the database is related to the one or more parameters.

137. The apparatus of claim 136, wherein said processor constructs the reference database over a spectrum of wavelengths, said optics provides radiation having wavelengths that comprise said spectrum and said detector detects ellipsometric parameters at a plurality of wavelengths over said spectrum of wavelengths.

138. The apparatus of claim 137, wherein said processor compares ellipsometric parameters at wavelengths in a selected portion of the spectrum to a portion of the database.

139. The apparatus of claim 138, said spectrum comprising ultraviolet wavelengths, wherein said portion consists of wavelengths in the ultraviolet range.

140. The apparatus of claim 135, wherein said optical element polarizes the broadband radiation so that the sampling beam is in the TE or TM mode, and the detector detects ellipsometric parameters in the TE or TM mode.

141. The apparatus of claim 135, wherein said detector detects a zeroth order diffraction of said beam from said diffracting structure.

142. The apparatus of claim 135, wherein said optics produces a sampling beam in the TE or TM mode.

143. The apparatus of claim 135, wherein said oblique angle is in the range of about 40 to 80 degrees.

144. The apparatus of claim 135, wherein said detector detects a zeroth order diffraction of said beam from said diffracting structure.

145. The apparatus of claim 135, wherein said processor constructs a reference database comprising a plurality of functions each of said functions corresponding to one or more parameters of said diffracting structure and providing values of intensity at said plurality of wavelengths.

146. The apparatus of claim 135, each of said functions corresponding to a probable shape of lines, linewidth, height or side wall angle of said diffracting structure.

147. The apparatus of claim 135, wherein said processor constructs said database by means of a model without the use of reference samples.

148. The apparatus of claim 135, further comprising a spectroscopic device measuring data related to film thickness and index of refraction information of the sample over a spectrum.

149. The apparatus of claim 135, said diffracting structure located adjacent to an associated structure, said apparatus further comprising a spectroscopic device measuring data related to characteristics of the associated structure.

150. The apparatus of claim 149, said spectroscopic device measuring data related to film thickness and index of refraction information of the associated structure over a spectrum.

151. The apparatus of claim 149, wherein said instrument comprises a spectroscopic ellipsometer, spectrophotometer or spectroreflectometer.

152. The apparatus of claim 151, wherein said instruction and optics employ common optical elements, said common elements comprising a broadband radiation source, a polarizer and a spectrometer.

153. The apparatus of claim 149, wherein said instrument and optics employ common optical elements, said common elements comprising also an analyzer, wherein said polarizer and analyzer are set to provide and pass radiation of substantially the same polarization when intensity data is detected from said diffracting structure, and to cause rotation between the polarizer and the analyzer when ellipsometric parameters are detected from the structure.

154. The apparatus of claim 135, wherein said apparatus comprises at least two of the following:

a spectroscopic ellipsometer a spectroscopic scatterometer and a spectroreflectometer.

155. The apparatus of claim 135, said apparatus comprising a spectroscopic scatterometer, and a spectroscopic ellipsometer and/or a spectroreflectometer.