Source: http://www.google.com/patents/US7324216?dq=7,003,515
Timestamp: 2014-07-11 22:58:37
Document Index: 690099480

Matched Legal Cases: ['Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60']

Patent US7324216 - Sub-nanometer overlay, critical dimension, and lithography tool projection ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign in<nobr>Advanced Patent Search</nobr>PatentsA method of processing a substrate on which a layer of photoresist has been applied, the method involving: exposing the layer of photoresist to radiation that carries spatial information to generate exposure-induced changes in the layer of photoresist that form a pattern having one or more features;...http://www.google.com/patents/US7324216?utm_source=gb-gplus-sharePatent US7324216 - Sub-nanometer overlay, critical dimension, and lithography tool projection optic metrology systems based on measurement of exposure induced changes in photoresist on wafersAdvanced Patent SearchPublication numberUS7324216 B2Publication typeGrantApplication numberUS 11/208,424Publication dateJan 29, 2008Filing dateAug 19, 2005Priority dateAug 19, 2004Fee statusLapsedAlso published asUS20060050283, WO2006023612A2, WO2006023612A3Publication number11208424, 208424, US 7324216 B2, US 7324216B2, US-B2-7324216, US7324216 B2, US7324216B2InventorsHenry Allen HillOriginal AssigneeZetetic InstituteExport CitationBiBTeX, EndNote, RefManPatent Citations (68), Non-Patent Citations (20), Referenced by (3), Classifications (9), Legal Events (4) External Links: USPTO, USPTO Assignment, EspacenetSub-nanometer overlay, critical dimension, and lithography tool projection optic metrology systems based on measurement of exposure induced changes in photoresist on wafersUS 7324216 B2Abstract A method of processing a substrate on which a layer of photoresist has been applied, the method involving: exposing the layer of photoresist to radiation that carries spatial information to generate exposure-induced changes in the layer of photoresist that form a pattern having one or more features; and before developing the exposed photoresist, interferometrically obtaining measurements of the pattern in the exposed layer of photoresist for determining at least one of (1) locations of the one or more features of the pattern and (2) magnitudes of the exposure-induced changes.
RELATED APPLICATIONS The following applications are related to the present application: U.S. Ser. No. 60/447,254, filed Feb. 13, 2003, and U.S. Ser. No. 10/778,371, filed Feb. 13, 2004, both of which are entitled �Transverse Differential Interferometric Confocal Microscopy,� (ZI-40); U.S. Ser. No. 60/448,360, filed Feb. 19, 2003, and U.S. Ser. No. 10/782,057, filed Feb. 19, 2004, both of which are entitled �Longitudinal Differential Interferometric Confocal Microscopy For Surface Profiling,� (ZI-41); U.S. Ser. No. 60/448,250, filed Feb. 19, 2003, and U.S. Ser. No. 10/782,058, filed Feb. 19, 2004, both of which are entitled �Method And Apparatus For Dark Field Interferometric Confocal Microscopy,� (ZI-42); U.S. Ser. No. 60/443,980, filed Jan. 31, 2003 and U.S. Ser. No. 10/765,254, filed Jan. 27, 2004, entitled �Utility Leaky Guided Wave Modes Used in Interferometric Confocal Microscopy to Measure Properties of Trenches,� (ZI-46); U.S. Ser. No. 60/459,425, filed Apr. 1, 2003, entitled �Apparatus And Method For Joint Measurement Of Fields Of Scattered/Reflected Orthogonally Polarized Beams By An Object In Interferometry,� and U.S. Ser. No. 10/816,180, filed Apr. 1, 2004, entitled �Apparatus And Method For Joint Measurement Of Fields Of Scattered/Reflected Or Transmitted Orthogonally Polarized Beams By An Object In Interferometry,� (ZI-50); U.S. Ser. No. 60/485,507, filed Jul. 7, 2003, and U.S. Ser. No. 10/886,010, filed Jul. 7, 2004, both of which are entitled �Apparatus And Method For High Speed Scan For Sub-Wavelength Defects And Artifacts In Semiconductor Metrology,� (ZI-52); U.S. Ser. No. 60/485,255, filed Jul. 7, 2003, entitled �Apparatus and Method for Ellipsometric Measurements With High Spatial Resolution,� (ZI-53); U.S. Ser. No. 60/507,675, filed Oct. 1, 2003, entitled �Method and Apparatus for Enhanced Resolution of High Spatial Frequency Components of Images Using Standing Wave Beams in Non-Interferometric and Interferometric Microscopy,� (ZI-55); U.S. Ser. No. 60/602,046, filed Aug. 16, 2004, and U.S. Ser. No. (T.B.D.), filed Aug. 16, 2005, both of which are entitled �Apparatus and Method for Joint and Time Delayed Measurements of Components of Conjugated Quadratures of Fields of Reflected/Scattered Beams by an Object in Interferometry,� (ZI-57); U.S. Ser. No. 60/568,774, filed May 6, 2004, entitled �Apparatus and Methods for Measurement of Critical Dimensions of Features and Detection of Defects in UV, VUV, and EUV Lithography Masks,� (ZI-60); U.S. Ser. No. 60/569,807, filed May 11, 2004, entitled �Apparatus and Methods for Measurement of Critical Dimensions of Features and Detection of Defects in UV, VUV, and EUV Lithography Masks,� (ZI-61); U.S. Ser. No. 60/573,196, filed May 21, 2004, and U.S. Ser. No. 11/135,605, filed May 23, 2005, both of which are entitled �Apparatus and Methods for Overlay, Alignment Mark, and Critical Dimension Metrologies Based on Optical Interferometry,� (ZI-62); U.S. Ser. No. 60/571,967, filed May 18, 2004, entitled �Apparatus And Methods For Measurement Of Critical Dimensions Of Features And Detection Of Defects In UV, VUV, and EUV Lithography Masks,� (ZI-63); U.S. Ser. No. 60/602,999, filed Aug. 19, 2004, entitled �Sub-Nanometer Overlay, Critical Dimension, and Lithography Tool Projection Optic Metrology Systems Based on Measurement of Exposure Induced Changes in Photoresist on Wafers,� (ZI-64); and U.S. Ser. No. 60/618,483, filed Oct. 13, 2004, entitled �Sub-Nanometer Overlay, Critical Dimension, and Lithography Tool Projection Optic Metrology Systems Based on Measurement of Exposure Induced Changes in Photoresist on Wafers,� (ZI-65), all of which are incorporated herein by reference.
Overlay metrology saves subsequent process steps that would be built on a faulty foundation in case of an alignment error. Overlay metrology provides the information that is necessary to correct the alignment of the stepper-scanner and thereby minimize overlay error on subsequent wafers. Moreover, overlay errors detected on a given wafer after exposing and developing the photoresist can be corrected by removing the photoresist and repeating the lithography step on a corrected stepper-scanner. If the measured error is minor, parameters for subsequent steps of the lithography process could be adjusted based on the output of the overlay metrology to avoid excursions. If overlay error is measured subsequently, e.g., after the etch step that typically follows the develop step, it can be used to �scrap� severely mis-processed wafers, or to adjust process equipment for better performance on subsequent wafers, i.e., APC.
Prior overlay metrology methods use built-in test patterns etched or otherwise formed into or on the various layers during the same set of lithography steps that form the patterns for circuit elements on the wafer. The typical BiB pattern consists of two concentric squares, formed on a lower and an upper layer, respectively. �Bar-in-bar� is a similar pattern with just the edges of the �boxes� demarcated and broken into disjoint line segments. Typically one is the upper pattern and the other is the lower pattern, i.e., corresponding to earlier and later steps in the process. There are other patterns used for overlay metrology. The squares or bars are formed by lithographic and other processes used to make planar structures, e.g., CMP. Currently, the patterns for the boxes or bars are stored on lithography masks and projected onto the wafer. Other methods for putting the patterns on the wafer are possible, e.g., direct electron beam writing from computer memory, etc.
In one form of the prior art, a high performance microscope imaging system combined with image processing software estimates overlay error for the two layers. The image processing software uses the intensity of light at a multitude of pixels. Obtaining the overlay error accurately requires a high quality imaging system and means of focusing it. Some of this prior art is reviewed by the article �Semiconductor Pattern Overlay�, by Neal T. Sullivan, Handbook of Critical Dimension Metrology and Process Control, Kevin M. Monahan, ed., SPIE Optical Engineering Press, CR52, p. 160. A. Starikov, D. J. Coleman, P. J. Larson, A. D. Lapata, and W. A. Muth in �Accuracy of Overlay Measurements: Tool and Mark Asymmetry Effects,� Optical Engineering, 31, 1992, p. 1298, teach measuring overlay at one wafer orientation, rotating the wafer by 180�, measuring overlay again and attributing the difference to tool errors and overlay mark asymmetry.
The �average reflectivity� approximation for the interaction of light with gratings, as employed by U.S. Pat. No. 4,757,207, greatly simplifies the problem of light interaction with a grating but neglects much of the diffraction physics. The model used to interpret the data has four distinct regions whose respective reflectivities are determined by the combination of layers formed by the substrate and the overlaid patterns and by the respective materials in the substrate and patterns. Equation (1) in the U.S. Pat. No. 4,757,207 clearly indicates that these regions do not interact, i.e., via diffraction, as the total reflectivity of the structure is a simple average of the four reflectivities with area weighting.
In one type of measurement process of WO 02/065545 A2, a microstructure is illuminated and the intensity of reflected or diffracted radiation is detected as a function of the radiation's wavelength, the incidence direction, the collection direction, or polarization state (or a combination of such factors). Direction is typically specified as a polar angle and azimuth, where the reference for the polar angle is the normal to the wafer and the reference for the azimuth is either some pattern(s) on the wafer or other marker, e.g., a notch or a flat for silicon wafers. The measured intensity data is then passed to a data processing machine that uses some model of the scattering from possible structures on the wafer. For example, the model may employ Maxwell's equations to calculate the theoretical optical characteristics as a function of measurement parameters (e.g., film thickness, line width, etc.), and the parameters are adjusted until the measured and theoretical intensities agree within specified convergence criteria. The initial parameter estimates may be provided in terms of an initial �seed� model of the measured structure. Alternatively, the optical model may exist as pre-computed theoretical characteristics as a function of one or more discretized measurement parameters, i.e., a �library�, that associates collections of parameters with theoretical optical characteristics. The �extracted� structural model has the structural parameters associated with the optical model which best fits the measured characteristics, e.g., in a least-squares sense.
The measurement method taught by McNeil uses diffraction characteristics consisting of spectroscopic intensity data. A similar method can also be used with ellipsometric data, using ellipsometric parameters such as tan ψ, cos Δ in lieu of intensity data. For example, Xinhui Niu in �Specular Spectroscopic Scatterometry in DUV Lithography,� Proc. SPIE 3677, pp. 159, 1999, uses a library approach. The library method can be used to simultaneously measure multiple model parameters (e.g. linewidth, edge slope, film thickness).
In International (PCT) application publication No. WO 99/45340 by Xu et al. disclose a method for measuring the parameters of a diffracting structure on top of laterally homogeneous, non-diffracting films. The disclosed method first constructs a �reference database� based on a priori information about the refractive index and film thickness of underlying films, e.g., from spectroscopic ellipsometry or reflectometry. The reference database has �diffracted light fingerprints� or �signatures� (either diffraction intensities, or alternatively ellipsometric parameters) corresponding to various combinations of grating shape parameters. The grating shape parameters associated with the signature in the reference database that matches the measured signature of the structure are then reported as the grating shape parameters of the structure.
In International (PCT) application publication No. WO 02/065545 A2 by A. Sezginer, K. Johnson, and F. E. Stanke and entitled �Overlay Alignment Metrology Using Diffraction Gratings,� alignment accuracy between two patterned layers is measured using a metrology target comprising substantially overlapping diffraction gratings formed in a test area of the layers being tested. An optical instrument illuminates all or part of the target area and measures the optical response. The instrument can measure transmission, reflectance, and/or polarization of the illumination and detected light. Overlay error or offset between those layers containing the test gratings is determined by a processor programmed to calculate an optical response for a set of parameters that include overlay error, using a model that accounts for diffraction by the gratings and interaction to the gratings with each others' diffracted field. The model parameters might also take account of manufactured asymmetries. The calculated and measured responses are iteratively compared and the model parameters changed to minimize the difference.
In International (PCT) application publication No. WO 02/069390 by Xinhui Niu and Nickhil Jakatdar and entitled �Grating Test Patterns And Methods For Overlay Metrology,� a metrology is described for determining bias or overlay error in lithographic processes. The metrology includes a set of diffraction test patterns, optical inspection techniques using spectroscopic ellipsometer or reflectometer, and a method of test pattern profile extraction. The metrology uses a set of diffraction gratings as the test patterns and thin film metrology equipment, such as spectroscopic ellipsometer or spectroscopic reflectometer. The profiles of the test patterns in the two successive layers are analyzed. Overlay information are obtained after processing the profile data. In procedure, a line-on-line overlay grating test patterns structure is described in which a second layer mask is placed in the center of a clear line in a first layer mask. In a second procedure, a line-on-line overlay grating test patterns structure is described in which a second layer mask is placed in the center of a dark line in the first mask.
In International (PCT) application publication No. WO 02/24723 A2 by B. Brill, M. Finarov, and D. Scheiner and entitled �Lateral Shift Measurement Using An Optical Technique,� a method is described for controlling layers alignment in a multi-layer sample, such as in semiconductor wafers based on detecting a diffraction efficiency of radiation diffracted from the patterned structures located one above the other in two different layers of the sample.
OCDR is used to measure surface profiles of wafers such as described by in the article �Optical Coherency-Domain Reflectometry : A New Optical Evaluation Technique� by R. C. Youngquist, S. Carr, and D. E. N. Davies, Opt. Lett., 12. pp. 158 (1987). OCDR of prior art yields accurate information about the height profile of a surface but does not yield corresponding accurate information about the transverse location of features on a patterned wafer.
Bleaching or changes of the imaginary part of the refractive index, changes in the real part of the refractive index, changes in the density, and changes in the thickness of a photoresist layer on exposure are well known phenomena which occur in many photoresists such as described in articles by A. Erdmann, C. Henderson, and C. G. Willson, J. Appl. Phys. 89, p 8163 (2001) entitled �Impact of exposure induced refractive index changes of photoresists on the photolithographic process,� by H.-K. Oh, Y.-S. Sohn, M.-G. Sung, Y.-M. Lee, E.-M. Lee, S.-H. Byun,I. An, K.-S. Lee, and I.-H. Park, Advances in Resist Technology and Processing XVI, Proceedings of SPIE 3678, p 643 (1999) entitled �Refractive Index Change during Exposure for 193 nm Chemically Amplified Resist,� and by A. Kewitsch and A. Yariv, Appl. Phys. Lett. 68, p 455 (1996). Erdmann, Henderson, and Willson report for example that the change on exposure of the real part of the refractive index in a series of diazonaphthoquinone-novolac (DNQ-novolac) photoresists can be both positive and negative and could take on values as large as 0.05. Similar changes of the imaginary part of the refractive index on exposure of photoresist are also reported. Changes in the density are noted for example in the cited article by Kewitsch and Yariv and changes in the thickness of photoresist on exposure are described for example in cited article by H.-K. Oh et al.
At least some embodiments of the present invention are distinct from the metrologies described in commonly owned U.S. Provisional Patent Applications No. 60/568,774 (ZI-60) entitled �Apparatus And Methods For Measurement of Critical Dimensions Of Features And Detection Of Defects In UV, VUV, And EUV lithography Masks,� No. 60/569,807 (ZI-61) entitled �Apparatus And Methods For Measurement Of Critical Dimensions Of Features And Detection Of Defects In UV, VUV, And EUV Lithography Masks,� No. 60/573,196 (ZI-62) entitled �Apparatus And Methods For Overlay, Alignment Mark, And Critical Dimension Metrologies Based on Optical Interferometry,� and No. 60/571,967 (ZI-63) entitled �Apparatus And Methods For Measurement Of Critical Dimensions Of Features And Detection Of Defects In UV, VUV, And EUV lithography Masks� wherein measurements are made of locations and properties of patterns or portions of patterns in processed wafers and not of patterns or portions of patterns in photoresist layers generated by exposure induced changes in the refractive index, density and/or thickness of the photoresist layer with or without post exposure treatment. Each of the four cited provisional applications are by Henry A. Hill and the contents of each of the four cited provisional applications are herein incorporated in the entirety by reference.
U ⁡ ( P ) = C ⁢ ⁢ ⅇ ⅈ ⁢ ⁢ k ⁡ ( r ′ + s ′ ) ⁢ ⁢ ∫ η ⁢ ∫ ξ ⁢ ⅇ - ⅈ ⁢ ⁢ k ⁡ ( p ⁢ ⁢ ξ + q ⁢ ⁢ η ) + ⅈ ⁢ ⁢ k ⁡ ( ξ 2 + η 2 ) ⁢ ⁢ z r ′ ⁢ ⁢ 2 ⁢ ⅆ ξ ⁢ ⁢ ⅆ η ( 1 ) where C is a constant, ξ and η are the x and y coordinates of point O in the pupil, z0 is the location of point P0 in the z direction from the plane from which r′ is measured, k=2π/λ is the free space wavenumber for free space wavelength λ, r′ and s′ are defined in FIG. 5, and
p = l - l 0 ( 3 ) q = m - m 0 , where l 0 = - x 0 r ′ , l = x s ′ , ( 4 ) m 0 = - y 0 r ′ , m = y s ′ . The features of a spot comprising a single feature element or an array of elements forming a grating used in a overlay metrology system, a CD metrology system, a metrology system for acquiring information about the location of the PO optic axis, or a metrology system for acquiring information about the PO aberrations generally comprise high aspect ratios with respect to element lengths and separations. This property is used to advantage by specifying the pupil of the imaging system to be rectangular in cross-section with the boundaries of the rectangle aligned with the boundaries of the elements and selecting the aspect ratio of the rectangle to optimize performance of the linear displacement interferometric metrology system. The optimization of performance is used to obtain a high resolution in one dimension that is equivalent to a low k1{tilde under (>)}� where the resolution is given by k1 (λ/NA).
Another procedure is to not eliminate the contribution of forward reflected/scattered component in the measured conjugated quadratures but to restrict the range of values in ξ in Equation (1) to either limit the contribution to the measured conjugated quadrature to a single diffraction order from the arrays of elements comprising more than one element or in the case of an array comprising a single element, to prevent the generation of undesired contributions to the reflected/scattered component by multiple reflections between widely separated elements. The contributions of the forwarded/scattered components and the backscattered component are separated in the another procedure by the use of a form of phase sensitive detection such as described in commonly owned U.S. Provisional Patent Application No. 60/460,129 (ZI-51) and U.S. patent application Ser. No. 10/816,172 (ZI-51) wherein both are entitled �Apparatus and Method for Measurement of Fields of Forward Scattered/Reflected and Backscattered Beams by an Object in Interferometry,� both of which are by Henry A. Hill, and the contents of the provisional and non-provisional patent applications are herein incorporated in their entirety by reference.
θD≅−θI, (6)θI≈1. (7)
Δ ⁢ ⁢ θ ≅ λ l ⁢ ⁢ sec ⁢ ⁢ θ D . ( 8 ) The values of (ξ2+ξ1)/2 and (ξ2−ξ1) are determined in this case by θD and Δθ, respectively.
( ξ 2 , lim s ′ ) = ( 3 2 ) ⁢ ( w h ) . ( 9 ) For the example of h=100 nm and w=200 nm, the corresponding limiting value ξ2,lim is
ξ 2 , lim = 3 ⁢ ⁢ s ′ ( 10 ) with arctan ⁢ ⁢ ( ξ 2 , lim s ′ ) = 71.6 ⁢ ⁢ degrees . ( 11 ) A value of 71.6 degrees corresponds to a NA=0.95 which is compatible with imaging system designs.
U ⁡ ( P ) = 4 ⁢ ⁢ a ξ ⁢ a η ⁢ ⁢ C ⁢ ⁢ ⅇ ⅈ ⁢ ⁢ k ⁡ ( r ′ + s ′ ) - ⅈ ⁢ ⁢ k ⁡ [ ( p ⁢ ⁢ ξ 0 + q ⁢ ⁢ η 0 ) - 1 2 ⁢ ( ξ 0 2 + η 0 2 ) ⁢ ⁢ z 0 r ′2 ] � { sin ⁢ ⁢ c ⁢ ⁢ k ⁢ ⁢ α ξ ⁢ a ξ ⁢ ⁢ sin ⁢ ⁢ c ⁢ ⁢ k ⁢ ⁢ α η ⁢ a η - k ( β ⁢ ⁢ a ξ 2 2 ) 2 ⁢ ⁢ f 2 ⁡ ( k ⁢ ⁢ α ξ ⁢ a ξ ) - k ( β ⁢ ⁢ a η 2 2 ) 2 ⁢ ⁢ f 2 ⁡ ( k ⁢ ⁢ α η ⁢ a η ) - 2 ⁢ ⁢ k ( β ⁢ ⁢ a ξ 2 2 ) ⁢ ( β ⁢ ⁢ a η 2 2 ) ⁢ ⁢ f 1 ⁢ ⁢ ( k ⁢ ⁢ α ξ ⁢ ⁢ a ξ ) ⁢ ⁢ f 1 ⁢ ⁢ ( k ⁢ ⁢ α η ⁢ a η ) + � + ⅈ ⁢ [ k ( β ⁢ ⁢ a ξ 2 2 ) ⁢ ⁢ f 1 ⁢ ⁢ ( k ⁢ ⁢ α ξ ⁢ a ξ ) + k ( β ⁢ ⁢ a η 2 2 ) ⁢ ⁢ f 1 ⁢ ⁢ ( k ⁢ ⁢ α η ⁢ a η ) ] + � ⁢ } ( 12 ) where β = z 0 r ′2 , ( 13 ) ξ 0 = ( ξ 2 + ξ 1 ) 2 , η 0 = ( η 2 + η 1 ) 2 , α ξ = p - ξ 0 ⁢ β , α η = q - η 0 ⁢ β , a ξ = ( ξ 2 - ξ 1 ) 2 , a η = ( η 2 - η 1 ) 2 . and f 1 ⁡ ( k ⁢ ⁢ α ⁢ ⁢ a ) = sin ⁢ ⁢ c ⁢ ⁢ k ⁢ ⁢ α ⁢ ⁢ a - 2 ⁡ [ cos ⁢ ⁢ k ⁢ ⁢ α ⁢ ⁢ a - sin ⁢ ⁢ c ⁢ ⁢ k ⁢ ⁢ α ⁢ ⁢ a ( k ⁢ ⁢ α ⁢ ⁢ a ) 2 ] ⁢ = 1 3 - ( k ⁢ ⁢ α ⁢ ⁢ a ) 2 5 + � ⁢ , ( 14 ) f 2 ⁢ ⁢ ( k ⁢ ⁢ α ⁢ ⁢ a ) = sin ⁢ ⁢ c ⁢ ⁢ k ⁢ ⁢ α ⁢ ⁢ a + 4 ⁡ [ cos ⁢ ⁢ k ⁢ ⁢ α ⁢ ⁢ a - 3 ⁢ ⁢ f 1 ⁢ ⁢ ( k ⁢ ⁢ α ⁢ ⁢ a ) ] ⁢ = 1 5 + � ( 15 ) The properties of the measurement and reference beams are described in the context of specific embodiments of the present invention. However, it is appropriate to describe here a very general property that is achieved through the design of the reference beams used in the linear displacement interferometric metrology systems. The very general property of various embodiments of the present invention is that the reference beam is generated with properties such that the phase of conjugated quadratures corresponding to the interference cross-term between the reference beam and the reflected/scattered measurement beam from a given feature in the electrical interference values generated by detection of mixed output beams of the linear displacement interferometric metrology systems has no dependence on either x or y. The phase term in U(P) given by Equation (12) that is a function x is the term containing p in the ik(pξ0+qη0) phase term. Thus the x dependence of a phase term for the reference beam must be equal to ikxξ0/s′ in order to achieve the very general property.
The measurement of an error in an overlay, an error in a CD in a spot, information about the location of the PO optic axis, or information about the PO aberrations comprising a single pattern feature is based in part on a linear displacement interferometric measurement such as described in cited U.S. Provisional Patent Applications No. 60/568,774 (ZI-60), No. 60/569,807 (ZI-61), No. 60/573,196 (ZI-62), No. 60/571,967 (ZI-63), No. 60/602,999 (ZI-64), No. 60/618,483 (ZI-65) and No. 60/624,707 (ZI-68). Provisional Patent Applications No. 60/602,999, No. 60/618,483, and No. 60/624,707 are each entitled �Sub-Nanometer Overlay, Critical Dimension, And Lithography Tool Projection Optic Metrology Systems Based On Measurement Of Exposure Induced Changes In Photoresist On Wafers� and are by Henry A. Hill. The feature is formed by exposure induced changes in one or more of the refractive index, density, and thickness of the photoresist on a substrate with or without post exposure treatment, e.g. post exposure baking, vacuum treatment, and silylating. The feature may be written in the scribe-lines of the wafer and the spatial properties of the feature designed optimally for overlay metrology, CD metrology, location of PO optic axis metrology, PO aberration metrology, TIS metrology, WIS metrology, or APC.
Φ 1 = - k ⁢ [ ( p ⁢ ⁢ ξ 0 ′ + q ⁢ ⁢ η 0 ′ ) - 1 2 ⁢ ( ξ 0 ′ ⁢ ⁢ 2 + η 0 ′ ⁢ ⁢ 2 ) ⁢ ⁢ z 0 r ′ ⁢ ⁢ 2 ] + arctan ⁢ { k ⁢ ⁢ β ⁡ ( a ξ ′ ⁢ ⁢ 2 + a η ′ ⁢ ⁢ 2 ) 2 6 ⁢ ⁢ sin ⁢ ⁢ c ⁢ ⁢ k ⁢ ⁢ α ξ ′ ⁢ a ξ ′ ⁢ ⁢ sin ⁢ ⁢ c ⁢ ⁢ k ⁢ ⁢ α η ′ ⁢ ⁢ a η ′ } + � ( 16 ) where ξ′0 is determined by θD, a′ξis determined by the size of the spot that is being imaged and accordingly Δθ. Also the point spread function represented by Equation (12) can be used to derive the dependence of the phase Φ2 of a measured conjugated quadrature or differential conjugated quadrature on the translation of a grating pattern through the spot being imaged by the interferometric imaging system including the effects of the imaging system for delivering the measurement beam to the spot with the result
Φ 2 = k ⁢ [ ( x 0 ⁡ ( ξ 0 + ξ 0 ′ ) + y 0 ⁡ ( η 0 + η 0 ′ ) ) r ′ ] + k ⁢ ⁢ 1 2 ⁢ ( ξ 0 2 + ξ 0 ′ ⁢ ⁢ 2 + η 0 2 + η 0 ′ ⁢ ⁢ 2 ) ⁢ ⁢ z 0 r ′ ⁢ ⁢ 2 + arctan ⁢ { k ⁢ ⁢ z 0 6 ⁢ ⁢ sin ⁢ ⁢ c ⁢ ⁢ k ⁢ ⁢ α ξ ⁢ a ξ ⁢ ⁢ sin ⁢ ⁢ c ⁢ ⁢ k ⁢ ⁢ α η ⁢ a η ⁢ ( a ξ 2 + a η 2 ) r ′ ⁢ ⁢ 2 } + � + arctan ⁢ { k ⁢ ⁢ z 0 6 ⁢ ⁢ sin ⁢ ⁢ c ⁢ ⁢ k ⁢ ⁢ α ξ ⁢ a ξ ′ ⁢ ⁢ sin ⁢ ⁢ c ⁢ ⁢ k ⁢ ⁢ α η ⁢ a η ′ ⁢ ( a ξ ′ ⁢ ⁢ 2 + a η ′ ⁢ ⁢ 2 ) r ′ ⁢ ⁢ 2 } + � ( 17 ) where ξ0 is determined by θI and aξ will be set by the NA of the input beam delivery system of the measurement beam.
x 0 = λ ⁡ ( r ′ ξ 0 + ξ 0 ′ ) ⁢ ⁢ ( Φ 2 2 ⁢ ⁢ π ) + � ( 18 ) where 1 3 ≲ ( r ′ ξ 0 + ξ 0 ′ ) ≲ 1. ( 19 ) The ratio of the pitch Λ of a grating to the wavelength λ is
Λ λ = r ′ ξ 0 + ξ 0 ′ + � ⁢ . ( 20 ) Therefore the measurement of the phase Φ2 to an accuracy of 6 milliradian for a λ=200 nm and a Λ=100 nm would yield a relative position accuracy of 0.1 nm mod Λ_for the portion of the grating in the spot. The displacement redundancy of Λ is a consequence of the phase redundancy of 2π in Φ2.
The relative location of two gratings located on the same photoresist layer of a wafer is determined by scanning the respective portions of wafer corresponding to the two gratings and recording the spatial separation in x0 that corresponds to a change in Φ0 mod 2π. The relative location of the two gratings corresponds to the measured spatial separation in x0 mod Λ. The pitch redundancy generally will not present a problem when the measured separation mod Λ is used in an overlay metrology system. If however it is desired to remove the pitch redundancy, an array of additional gratings may be used in the manner described herein in the section entitled �Location Of A Feature: Grating Type�_for the removal of the pitch redundancy encountered in the feature position determination.
∂ Φ 2 ∂ z 0 = ⁢ k ⁢ ⁢ 1 2 ⁡ [ ξ 0 2 + ξ 0 ′ ⁢ ⁢ 2 + η 0 2 + η 0 ′ ⁢ ⁢ 2 ] ⁢ 1 r ′ ⁢ ⁢ 2 + ⁢ k 6 ⁢ ⁢ sin ⁢ ⁢ ck ⁢ ⁢ α ξ ⁢ a ξ ⁢ sin ⁢ ⁢ ck ⁢ ⁢ α η ⁢ a η ⁡ [ ( a ξ 2 + α η 2 ) r ′ ⁢ ⁢ 2 + ( a ξ ′ ⁢ ⁢ 2 + α η ′ ⁢ ⁢ 2 ) r ′2 ] + � ( 21 ) evaluated at z0=0. The difference in the height of the surface of the wafer at the sites of the two gratings is measured by the use of a differential interferometric confocal and/or an interferometric non-confocal microscopy system preferentially operating in a dark field mode. The differential interferometric microscopy systems are such as described herein in the section entitled �Differential Interferometric Microscopy Systems.� The differential interferometric microscopy systems may in addition be used to detect defects at either of the two sites.
Different pinholes of pinhole array 12 are used to obtain the respective measured values of Φ0 wherein the portion of the interferometric imaging system imaging the grating located on the interior process layer is compensated for the aberrations introduced by the object space being located interior to the surface of the wafer. The compensation uses the technique described in commonly owned U.S. Provisional Patent No. 60/444,707 (ZI-44) and U.S. patent application Ser. No. 10/771,785 (ZI-44) entitled �Compensation for Effects of Mismatch in Indices of Refraction at a Substrate-Medium Interface in Confocal and Interferometric Confocal Microscopy� wherein both are to Henry A. Hill and the contents of both the provisional and non-provisional patent applications are herein incorporated in their entirety by reference.
The pitch redundancy generally will not present a problem when the measured separation mod Λ is used in an overlay metrology system. If however it is desired to remove the pitch redundancy, an array of additional gratings may be used in the manner described herein for the removal of the pitch redundancy described herein in the section entitled �Location of a Feature; Grating type�.
There may be an offset error as a result of the affect of imaging of a spot interior of the wafer in each of the two scans of the wafer. However, the offset error will cancel out to a high level in computing the average of the two measured values of x0. The degree to which the offset errors cancel out can be checked by adapting the procedure described herein in the section entitled �Location of an Alignment Mark: Grating type� for spots comprising a single scattering element. In this case, the independent procedure can be for example based on a Scanning Electron Microscope (SEM).
A higher level of cancellation of the offset error can be achieved by using a set of an even number of gratings on one process layer and an odd number of gratings on the second process layer with the gratings on the two process layers interleaved transversely such as shown in FIG. 1 g. If the profiles of either or both of the two respective wafer surfaces are not flat, there will be an error introduced in the average value of the two measured values of x0 that are used in the determination of the spacing of the two gratings. The difference in the height of the two surfaces of the wafer at the sites of the two gratings is measured by the use of a differential interferometric confocal and/or an interferometric non-confocal microscopy system preferentially operating in a dark field mode. The differential interferometric microscopy systems are such as described herein in the section entitled �Differential Interferometric Microscopy Systems.� The differential interferometric microscopy systems may in addition be used to detect defects at either of the two sites.
The description of the PO optic axis and aberration metrology systems are given herein in sections entitled �Location Of Feature: Single Element Type,� �Location Of A Feature: Grating Type,� and �Relative Location Of Two Gratings Located On Same Photoresist Layer Of Wafer.� The feature used in the PO optic axis and aberration metrology systems may be written in the scribe-lines of the wafer and the spatial properties of the feature designed optimally for location determination of PO optic axis and for aberration monitoring of PO.
There are different ways to configure source 18 and beam-conditioner 22 to meet the input beam requirements of the different embodiments of the present invention. Examples of beam-conditioners that may be used in either first or the second technique comprise combinations of a two frequency generator and phase shifting type of beam-conditioner such as described in commonly owned U.S. Provisional Patent Application No. 60/442,858 (ZI-47) entitled �Apparatus and Method for Joint Measurements of Conjugated Quadratures of Fields of Reflected/Scattered Beams by an Object in Interferometry� and corresponding U.S. patent application Ser. No. 10/765,368 (ZI-47) entitled �Apparatus and Method for Joint Measurements of Conjugated Quadratures of Fields of Reflected/Scattered and Transmitted Beams by an Object in Interferometry� wherein both of the applications are by Henry A. Hill and the contents of which are incorporated herein in their entirety by reference.
Other examples of beam-conditioners that may be used in either the first or the second technique comprise combinations of multiple frequency generators and phase shifting types of beam-conditioners such as described for example in commonly owned U.S. Provisional Patent Application No. 60/459,425 (ZI-50) entitled �Apparatus and Method for Joint Measurement of Fields of Scattered/Reflected Orthogonally Polarized Beams by an Object in Interferometry,� in corresponding U.S. patent application Ser. No. 10/816,180 (ZI-50) also entitled �Apparatus and Method for Joint Measurement of Fields of Scattered/Reflected Orthogonally Polarized Beams by an Object in Interferometry,� and in commonly owned U.S. Provisional Application filed Aug. 16, 2004 (ZI-57) entitled �Apparatus and Method for Joint And Time Delayed Measurements of Components of Conjugated Quadratures of Fields of Reflected/Scattered and Transmitted/Scattered Beams by an Object in Interferometry.� The three U.S. Provisional Patent Applications and the two U.S. patent applications are all by Henry A. Hill and the contents of which are incorporated herein in their entirety by reference.
With a continuation of the description of different ways to configure source 18 and beam-conditioner 22 to meet the input beam requirements of different embodiments of the present invention, source 18 will preferably comprise a pulsed source. There are a number of different ways for producing a pulsed source such as described in cited U.S. Provisional Application filed Aug. 16, 2004 (ZI-57) entitled �Apparatus and Method for Joint And Time Delayed Measurements of Components of Conjugated Quadratures of Fields of Reflected/Scattered and Transmitted/Scattered Beams by an Object in Interferometry.�
The conjugated quadratures of fields of return measurement beams are obtained by using a single or double or a homodyne detection method or bi- or quad-homodyne detection method or variants and extensions thereof. The bi- and quad-homodyne detection methods are described for example in cited U.S. Provisional Patent Application No. 60/442,858 (ZI-47) and U.S. patent application Ser. No. 10/765,368 (ZI-47). The variants and extensions of the bi- and quad-homodyne detection methods are described for example in cited U.S. Provisional Patent Application No. 60/459,425 (ZI-50), U.S. patent application Ser. No. 10/816,180 (ZI-50), and U.S. Provisional Patent Application filed Aug. 16, 2004 (ZI-57) entitled �Apparatus and Method for Joint And Time Delayed Measurements of Components of Conjugated Quadratures of Fields of Reflected/Scattered and Transmitted/Scattered Beams by an Object in Interferometry.�
The variants of the bi- and quad-homodyne detection methods obtain measurements of electrical interference signals wherein each measured value of an electrical interference signal contains simultaneously information about two orthogonal components of each of two conjugated quadratures of fields of scattered/reflected orthogonally polarized beams. The two orthogonal components of the two conjugated quadratures correspond to orthogonal components of conjugated quadratures such as described in cited U.S. Provisional Patent Application No. 60/459,425 (ZI-50) and cited corresponding U.S. patent application Ser. No. 10/816,180 (ZI-50) and entitled �Apparatus and Method for Joint Measurement of Fields of Scattered/Reflected Orthogonally Polarized Beams by an Object in Interferometry�.
The extensions of the bi- and quad-homodyne detection methods to N -dimensional bi- and quad-homodyne detection methods obtain simultaneous joint measurements N independent conjugated quadratures of fields such as described in cited U.S. Provisional Patent Application filed Aug. 16, 2004 (ZI-57) entitled �Apparatus and Method for Joint And Time Delayed Measurements of Components of Conjugated Quadratures of Fields of Reflected/Scattered and Transmitted/Scattered Beams by an Object in Interferometry.�
The first imaging system 100 is shown schematically in FIG. 1 c. Imaging system 100 is a catadioptric system such as described in commonly owned U.S. Pat. No. 6,552,852 B2 (ZI-38) and U.S. Pat. No. 6,717,736 (ZI-43) both of which are entitled �Catoptric and Catadioptric Imaging System� wherein both applications are to Henry A. Hill, the contents of the two cited patents incorporated herein in their entirety by reference.
The description of interferometer 100, a source 18, beam-conditioner 22, detector 70, and electronic processor and controller 80 is the same as corresponding portions of the descriptions of catoptric and catadioptric imaging systems given in U.S. Patent Provisional Patent Application No. 60/485,507 (ZI-52) entitled �Apparatus and Method for High Speed Scan for Subwavelength Defects in Semiconductor Metrology� and U.S. patent application filed Jul. 7, 2004 (ZI-52) entitled �Apparatus and Method for High Speed Scan for Subwavelength Defects in Semiconductor Metrology� wherein both are by Henry A. Hill and the contents of which are incorporated herein in their entirety by reference.
A number of different catadioptric imaging systems for far-field and near-field interferometric confocal microscopy have been described such as in cited U.S. Pat. No. 6,552,852 (ZI-38) and cited U.S. Pat. No. 6,717,736 (ZI-43); in commonly owned U.S. Provisional Patent Application Nos. 60/447,254 (ZI-40) entitled �Transverse Differential Interferometric Confocal Microscopy,� 60/448,360 (ZI-41) entitled �Longitudinal Differential Interferometric Confocal Microscopy,� 60/448,250 (ZI-42) entitled �Thin Film Metrology Using Interferometric Confocal Microscopy,� 60/442,982 (ZI-45) entitled �Interferometric Confocal Microscopy Incorporating Pinhole Array Beam-Splitter,� 60/459,425 (ZI-50) entitled �Apparatus and Method for Joint Measurement Of Fields Of Orthogonally Polarized Beams Scattered/Reflected By An Object In Interferometry,� 60/485,255 (ZI-53) entitled �Apparatus and Method for Ellipsometric Measurements with High Spatial Resolution,� 60/501,666 (ZI-54) entitled �Catoptric and Catadioptric Imaging Systems With Adaptive Catoptric Surfaces,� and 60/506,715 (ZI-56) entitled �Catoptric and Catadioptric Imaging Systems Comprising Pellicle Beam-Splitters And Non-Adaptive And Adaptive Catoptric Surfaces;� and U.S. patent applications Ser. No. 10/778,371 (ZI-40) entitled �Transverse Differential Interferometric Confocal Microscopy,� Ser. No. 10/782,057 (ZI-41) entitled �Longitudinal Differential Interferometric Confocal Microscopy,� Ser. No. 10/782,058 (ZI-42) entitled �Thin Film Metrology Using Interferometric Confocal Microscopy,� Ser. No. 10/765,229 (ZI-45) entitled �Interferometric Confocal Microscopy Incorporating Pinhole Array Beam-Splitter,� and Ser. No. 10/816,180 (ZI-50) entitled �Apparatus and Method for Joint Measurement Of Fields Of Orthogonally Polarized Beams Scattered/Reflected By An Object In Interferometry.� The eight provisional patent applications, and the corresponding five non-provisional patent applications are all by Henry A. Hill and the contents of each of which are incorporated herein in their entirety by reference. Other forms of non-catoptric or non-catadioptric microscopy imaging systems may be used for interferometer 100 without departing from the spirit or scope of the present invention.
The use of slit array 114 and non-polarizing beam-splitter 116 are also shown in FIG. 2 b. Catadioptric imaging system 100 comprises a section of catadioptric imaging system 200 shown schematically in FIG. 2 a that corresponds to the section shown in FIG. 1 c. Elements of catadioptric imaging system 200 shown in FIG. 2 a comprise two different media in order to generate an achromatic anastigmat such as described in cited U.S. Provisional Application No. 60/485,507 (ZI-52) and U.S. patent application filed Jul. 7, 2004 (ZI-52) and entitled �Apparatus and Method for High Speed Scan for Subwavelength Defects in Semiconductor Metrology.�
A variant of catadioptric imaging system 200 is shown in FIG. 2 b wherein catadioptric imaging system 110 is an anastigmat that is not achromatic such as described in cited U.S. Provisional Application No. 60/485,507 (ZI-52) and U.S. patent application filed Jul. 7, 2004 (ZI-52) and entitled �Apparatus and Method for High Speed Scan for Subwavelength Defects in Semiconductor Metrology.�
The description of imaging system 100 is continued with reference to FIG. 1 c. Lens sections 40 and 44 are pie sections of lens 240 and 244 shown in FIG. 2 a. Lens elements 250, 256, 254, and 258 in FIG. 1 c are the same elements lens elements 250, 256, 254, and 258 in FIG. 2 a. Convex lens 52 has a center of curvature the same as the center of curvature of convex lens 250. Convex lenses 250 and 52 are bonded together with pinhole beam-splitter 12 in between. Pinhole array beam-splitter 12 is shown in FIG. 1 c. The pattern of pinholes in pinhole array beam-splitter is chosen so that the image of pinhole beam-splitter 12 on detector 70 to match the pixel pattern of detector 70. An example of a pattern is a two dimensional array of equally spaced pinholes in two orthogonal directions. The pinholes may comprise circular apertures, rectangular apertures, or combinations thereof such as described in commonly owned U.S. patent application Ser. No. 09/917,402 (ZI-15) entitled �Multiple-Source Arrays for Confocal and Near-field Microscopy� by Henry A. Hill and Kyle Ferrio of which the contents thereof are incorporated herein in their entirety by reference. The pinholes may also comprise microgratings such as described in cited U.S. Provisional Patent Application No. 60/459,425. A non-limiting example of a pinhole array for pinhole array beam-splitter 12 is shown in FIG. 1 d having a spacing between pinholes of b with aperture size a.
For each of the first, second, and third embodiments of the present invention and variant thereof, the interferometric metrology systems may be configured in other embodiments to obtain information in the form of joint and non-joint measurements of the angular distribution of the differential conjugated quadratures of reflected/scattered beams from Porro type prisms in features and other features of measurement objects. The other embodiments comprise the apparatus described in cited U.S. Provisional Patent Application No. 60/501,666 (ZI-54) entitled �Catoptric and Catadioptric Imaging Systems With Adaptive Catoptric Surfaces� for the acquisition of information about angular distributions.
Embodiments of the present invention can be extended to operate not only into the VUV but also into the EUV. This is achieved by the use of pellicle type beam-splitters such as described in cited U.S. Provisional Patent Application No. 60/506,715 (ZI-56) and self supporting beam-splitters such as described by T. Haga, M. C. K. Tinone, M. Shimada. T. Ohkubo, and A. Ozawa in a article entitled �Soft x-ray multilayer beam splitters,� J. Synchrotron Rad., 5, pp 690 (1998). The description of techniques used in source 18 and beam-conditioner 22 for the generation of UV and VUV measurement and reference beams also can be used to generate EUV measurement and reference beams such as described in cited U.S. Provisional Application filed Aug. 16, 2004 (ZI-57) entitled U.S. Provisional Patent Application filed Aug. 16, 2004 (ZI-57) entitled �Apparatus and Method for Joint And Time Delayed Measurements of Components of Conjugated Quadratures of Fields of Reflected/Scattered and Transmitted/Scattered Beams by an Object in Interferometry.�
The difference in properties may be in the form of a surface profile, widths of two sections, depths of the two sections, or a particle located on the surface or in one of the two sections. A difference in the two widths will generate a difference in the amplitudes of the beams scattered by the entrance plane aperture formed by the feature sections. A difference in the depths of the two sections or the presence of a particle located in one of the two sections will modify the properties of leaky and non-leaky guided wave modes that are excited in the features by the respective measurement beams. The description of the excited leaky guided wave modes and the fields radiated by the excited leaky guided wave modes is the same as described in commonly owned U.S. Provisional Patent No. 60/443,980 (ZI-46) entitled �Leaky Guided Wave Modes Used in Interferometric Confocal Microscopy to Measure Properties of Trenches� and U.S. patent application Ser. No. 10/765,254 (ZI-46) with the same title and both by Henry A. Hill. The contents of both the patent application and the provisional patent application are here within incorporated in their entirety by reference.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS3628027Dec 17, 1969Dec 14, 1971Sulzer AgBeam deflecting and focusing means for photoelectric monitoring, counting or control apparatusUS3748015Jun 21, 1971Jul 24, 1973Perkin Elmer CorpUnit power imaging catoptric anastigmatUS4011011Dec 19, 1974Mar 8, 1977The Perkin-Elmer CorporationOptical projection apparatusUS4226501Oct 12, 1978Oct 7, 1980The Perkin-Elmer CorporationFour mirror unobscurred anastigmatic telescope with all spherical surfacesUS4272684Oct 6, 1978Jun 9, 1981Xerox CorporationOptical beam-splitting arrangements on object side of a lensUS4408884Jun 29, 1981Oct 11, 1983Rca CorporationOptical measurements of fine line parameters in integrated circuit processesUS4672196Feb 2, 1984Jun 9, 1987Canino Lawrence SMethod and apparatus for measuring properties of thin materials using polarized lightUS4685803Jan 23, 1986Aug 11, 1987Zygo CorporationMethod and apparatus for the measurement of the refractive index of a gasUS4733967Mar 19, 1987Mar 29, 1988Zygo CorporationApparatus for the measurement of the refractive index of a gasUS5220403Sep 30, 1992Jun 15, 1993International Business Machines CorporationApparatus and a method for high numerical aperture microscopic examination of materialsUS5241423Aug 1, 1991Aug 31, 1993International Business Machines CorporationOptical systemUS5327223Jun 19, 1992Jul 5, 1994International Business Machines CorporationMethod and apparatus for generating high resolution optical imagesUS5384639May 17, 1993Jan 24, 1995International Business Machines CorporationDepth measurement of high aspect ratio structuresUS5392118Sep 22, 1993Feb 21, 1995International Business Machines CorporationMethod for measuring a trench depth parameter of a materialUS5485317Oct 8, 1993Jan 16, 1996Solari Udine S.P.A.Optical system for light emitting diodesUS5602643Feb 7, 1996Feb 11, 1997Wyko CorporationMethod and apparatus for correcting surface profiles determined by phase-shifting interferometry according to optical parameters of test surfaceUS5614763Mar 13, 1995Mar 25, 1997Zetetic InstituteMethods for improving performance and temperature robustness of optical coupling between solid state light sensors and optical systemsUS5633972Nov 29, 1995May 27, 1997Trustees Of Tufts CollegeSuperresolution imaging fiber for subwavelength light energy generation and near-field optical microscopyUS5659420Sep 30, 1994Aug 19, 1997Kabushiki Kaisha Komatsu SeisakushoConfocal optical apparatusUS5699201Mar 27, 1995Dec 16, 1997Hewlett-Packard Co.Low-profile, high-gain, wide-field-of-view, non-imaging opticsUS5757493Oct 16, 1996May 26, 1998Tropel CorporationInterferometer with catadioptric imaging system having expanded range of numerical apertureUS5760901Jan 28, 1997Jun 2, 1998Zetetic InstituteMethod and apparatus for confocal interference microscopy with background amplitude reduction and compensationUS5828455Mar 7, 1997Oct 27, 1998Litel InstrumentsApparatus, method of measurement, and method of data analysis for correction of optical systemUS5894195May 3, 1996Apr 13, 1999Mcdermott; KevinElliptical axial lighting deviceUS5915048Jun 5, 1996Jun 22, 1999Zetetic InstituteMethod and apparatus for discriminating in-focus images from out-of-focus light signals from background and foreground light sourcesUS5923423Sep 4, 1997Jul 13, 1999Sentec CorporationHeterodyne scatterometer for detecting and analyzing wafer surface defectsUS6011654Sep 2, 1997Jan 4, 2000Carl-Zeiss-StiftungOptical arrangement for several individual beams with a segmented mirror fieldUS6018391Jan 28, 1998Jan 25, 2000Advantest CorporationMethod and apparatus for inspecting foreign matter by examining frequency differences between probing light beam and reference light beamUS6052231Jan 19, 1999Apr 18, 2000International Business Machines CorporationBeam dividing elements permitting projection of an image with high contrastUS6091496Jun 2, 1998Jul 18, 2000Zetetic InstituteMultiple layer, multiple track optical disk access by confocal interference microscopy using wavenumber domain reflectometry and background amplitude reduction and compensationUS6124931Jan 16, 1999Sep 26, 2000Zygo CorporationApparatus and methods for measuring intrinsic optical properties of a gasUS6271923Aug 27, 1999Aug 7, 2001Zygo CorporationInterferometry system having a dynamic beam steering assembly for measuring angle and distanceUS6330065Apr 28, 1999Dec 11, 2001Zygo CorporationGas insensitive interferometric apparatus and methodsUS6445453Aug 2, 2000Sep 3, 2002Zetetic InstituteScanning interferometric near-field confocal microscopyUS6447122Dec 20, 1999Sep 10, 2002Minolta Co., Ltd.Projection image display device using a reflective type display elementUS6469788Mar 27, 2001Oct 22, 2002California Institute Of TechnologyCoherent gradient sensing ellipsometerUS6480285Mar 16, 2000Nov 12, 2002Zetetic InstituteMultiple layer confocal interference microscopy using wavenumber domain reflectometry and background amplitude reduction and compensationUS6552805Jul 27, 2001Apr 22, 2003Zetetic InstituteControl of position and orientation of sub-wavelength aperture array in near-field microscopyUS6552852Dec 20, 2001Apr 22, 2003Zetetic InstituteCatoptric and catadioptric imaging systemsUS6597721Sep 21, 2000Jul 22, 2003Ut-Battelle, LlcMicro-laserUS6606159Aug 2, 2000Aug 12, 2003Zetetic InstituteOptical storage system based on scanning interferometric near-field confocal microscopyUS6667809Jul 27, 2001Dec 23, 2003Zetetic InstituteScanning interferometric near-field confocal microscopy with background amplitude reduction and compensationUS6707561Jul 5, 2000Mar 16, 2004Novartis AgSensor platform, apparatus incorporating platform, and process using the platformUS6714349Mar 25, 2002Mar 30, 2004Samsung Sdi Co., Ltd.Screen and projection display system with improved viewing angle characteristicUS6717736Feb 13, 2003Apr 6, 2004Zetetic InstituteCatoptric and catadioptric imaging systemsUS6753968Jan 30, 2003Jun 22, 2004Zetetic InstituteOptical storage system based on scanning interferometric near-field confocal microscopyUS6771374Jan 16, 2002Aug 3, 2004Advanced Micro Devices, Inc.Scatterometry based measurements of a rotating substrateUS6775009Jul 27, 2001Aug 10, 2004Zetetic InstituteDifferential interferometric scanning near-field confocal microscopyUS6806959Nov 21, 2001Oct 19, 2004Koninklijke Philips Electronics N.V.Measurement of surface defects on a movable surfaceUS6847029Jul 27, 2001Jan 25, 2005Zetetic InstituteMultiple-source arrays with optical transmission enhanced by resonant cavitiesUS6847452Jul 29, 2002Jan 25, 2005Zygo CorporationPassive zero shear interferometersUS20020074493Jul 27, 2001Jun 20, 2002Hill Henry A.Multiple-source arrays for confocal and near-field microscopyUS20020131179Dec 20, 2001Sep 19, 2002Hill Henry A.Catoptric and catadioptric imaging systemsUS20030174992Sep 27, 2002Sep 18, 2003Levene Michael J.Cladding surrounding a core where the cladding is configured to preclude propagation of electromagnetic energy of a frequency less than a cutoff frequency longitudinally through the core of the zero-mode waveguide; multibiosamplesUS20040201852Feb 4, 2004Oct 14, 2004Zetetic InstituteCompensation for effects of mismatch in indices of refraction at a substrate-medium interface in non-confocal, confocal, and interferometric confocal microscopyUS20040201853Feb 13, 2004Oct 14, 2004Zetetic InstituteTransverse differential interferometric confocal microscopyUS20040201854Feb 19, 2004Oct 14, 2004Zetetic InstituteLongitudinal differential interferometric confocal microscopyUS20040201855Feb 19, 2004Oct 14, 2004Zetetic InstituteMethod and apparatus for dark field interferometric confocal microscopyUS20040202426Feb 6, 2004Oct 14, 2004Zetetic InstituteMultiple-source arrays fed by guided-wave structures and resonant guided-wave structure cavitiesUS20040227950Apr 1, 2004Nov 18, 2004Zetetic InstituteApparatus and method for measurement of fields of backscattered and forward scattered/reflected beams by an object in interferometryUS20040227951Apr 1, 2004Nov 18, 2004Zetetic InstituteApparatus and method for joint measurement of fields of scattered/reflected or transmitted orthogonally polarized beams by an object in interferometryUS20040228008Apr 1, 2004Nov 18, 2004Zetetic InstituteMethod for constructing a catadioptric lens systemUS20040246486Jan 27, 2004Dec 9, 2004Zetetic InstituteInterferometric confocal microscopy incorporating a pinhole array beam-splitterUS20040257577Jan 27, 2004Dec 23, 2004Zetetic InstituteApparatus and method for joint measurements of conjugated quadratures of fields of reflected/scattered and transmitted beams by an object in interferometryUS20050036149Jul 7, 2004Feb 17, 2005Zetetic InstituteApparatus and method for high speed scan for detection and measurement of properties of sub-wavelength defects and artifacts in semiconductor and mask metrologyUS20050037272 *Sep 7, 2004Feb 17, 2005Olympus CorporationMethod and apparatus for manufacturing semiconductorUS20050111006Jul 7, 2004May 26, 2005Zetetic InstituteApparatus and method for ellipsometric measurements with high spatial resolutionUS20050111007Sep 24, 2004May 26, 2005Zetetic InstituteCatoptric and catadioptric imaging system with pellicle and aperture-array beam-splitters and non-adaptive and adaptive catoptric surfaces* Cited by examinerNon-Patent CitationsReference1U.S. Appl. No. 60/442,858, filed Jan. 27, 2003, Hill.2U.S. Appl. No. 60/442,982, filed Jan. 29, 2003, Hill.3U.S. Appl. No. 60/443,980, filed Jan. 31, 2003, Hill.4U.S. Appl. No. 60/444,707, filed Feb. 4, 2003, Hill.5U.S. Appl. No. 60/445,739, filed Feb. 7, 2003, Hill.6U.S. Appl. No. 60/447,254, filed Feb. 13, 2003, Hill.7U.S. Appl. No. 60/448,250, filed Feb. 19, 2003, Hill.8U.S. Appl. No. 60/448,360, filed Feb. 19, 2003, Hill.9U.S. Appl. No. 60/459,425, filed Apr. 11, 2003, Hill.10U.S. Appl. No. 60/459,493, filed Apr. 1, 2003, Hill.11U.S. Appl. No. 60/460,129, filed Apr. 3, 2003, Hill.12U.S. Appl. No. 60/485,255, filed Jul. 7, 2003, Hill.13U.S. Appl. No. 60/485,507, filed Jul. 7, 2003, Hill.14U.S. Appl. No. 60/501,666, filed Sep. 10, 2003, Hill.15U.S. Appl. No. 60/506,715, filed Sep. 26, 2003, Hill.16U.S. Appl. No. 60/507,675, filed Oct. 1, 2003, Hill.17U.S. Appl. No. 60/568,774, filed May 6, 2004, Hill.18U.S. Appl. No. 60/569,807, filed May 11, 2004, Hill.19U.S. Appl. No. 60/571,967, filed May 18, 2004, Hill.20U.S. Appl. No. 60/573,196, filed May 21, 2004, Hill.Referenced byCiting PatentFiling datePublication dateApplicantTitleUS7591408 *Jul 18, 2006Sep 22, 2009Hess & Knipps GmbhCamera-assisted adjustment of bonding head elementsUS8731272 *Jan 16, 2012May 20, 2014The Board Of Trustees Of The University Of IllinoisComputational adaptive optics for interferometric synthetic aperture microscopy and other interferometric imagingUS20140050382 *Jan 16, 2012Feb 20, 2014The Board Of Trustees Of The University Of IllinoisComputational Adaptive Optics for Interferometric Synthetic Aperture Microscopy and Other Interferometric Imaging* Cited by examinerClassifications U.S. Classification356/512, 355/53International ClassificationG03B27/42, G01B11/02Cooperative ClassificationG03F7/70633, G03F7/38, G03F7/70625European ClassificationG03F7/70L10D, G03F7/70L10BLegal EventsDateCodeEventDescriptionMar 20, 2012FPExpired due to failure to pay maintenance feeEffective date: 20120129Jan 29, 2012LAPSLapse for failure to pay maintenance feesSep 5, 2011REMIMaintenance fee reminder mailedNov 14, 2005ASAssignmentOwner name: ZETETIC INSTITUTE, ARIZONAFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:HILL, HENRY A.;REEL/FRAME:017017/0036Effective date: 20051018RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google