US 6,480,285 B1 · Multiple layer confocal interference microscopy using wavenumber domain reflectometry and background amplitude reduction and compensation

A method for discriminating an in-focus image from an out-of-focus image so as to reduce errors in information representing the in-focus image, comprising the steps of:

(a) producing a probe beam and a reference beam from an array of monochromatic point radiation sources;
(b) producing an in-focus return probe beam by directing the probe beam to an array of in-focus image points;
(c) producing antisymmetric spatial properties in the in-focus return probe beam;
(d) producing an in-focus reference beam;
(e) producing antisymmetric spatial properties in the in-focus reference beam;
(f) interfering the in-focus reference beam with a beam from a plurality of out-of-focus image points;
(g) interfering the in-focus reference beam with the in-focus return probe beam;
(h) reducing systematic and statistical errors in data produced by a detector to represent the information being determined by detecting the complex amplitude of the in-focus return probe beam as interference data by means of detector elements of the detector wherein the interference data comprises an interference term between the in-focus reference beam and the in-focus return probe beam and another interference term of substantially reduced amplitude between the out-of-focus image beams associated with out-of-focus image points and corresponding portions of the in-focus reference beam.

5 more elements

A method for discriminating an in-focus image from an out-of-focus image so as to reduce errors in information representative of the in-focus image, comprising the steps of:

(a) producing a probe beam and a reference beam from an array of monochromatic point radiation sources;
(b) producing an in-focus return probe beam by directing the probe beam to an array of in-focus image points, the in-focus return probe beam including a plurality of in-focus return sub-beams, each in-focus return sub-beam being associated with at least one in-focus image point of the array;
(c) producing antisymmetric spatial properties in each in-focus return sub-beam;
(d) producing an in-focus reference beam including a plurality of in-focus reference sub-beams, each in-focus reference sub-beam being associated with an in-focus return sub-beam, respectively;
(e) producing antisymmetric spatial properties in each in-focus reference sub-beam;
(f) interfering the in-focus reference beam with a beam from a plurality of out-of-focus image points;
(g) interfering the in-focus reference beam with the in-focus return probe beam;
(h) reducing systematic and statistical errors in data produced by a detector array to represent the information being determined by detecting the complex amplitudes of the in-focus return sub-beams as interference data by means of detector elements, respectively, of the detector array wherein the interference data comprises interference terms between corresponding in-focus reference sub-beams and in-focus return probe sub-beams and other interference terms of substantially reduced amplitudes between out-of-focus image beams associated with out-of-focus image points, respectively, and corresponding in-focus reference sub-beams.

5 more elements

A method for discriminating an in-focus image from an out-of-focus image so as to reduce errors in information representative of the in-focus image, comprising the steps of:

(a) producing a probe beam and a reference beam from a wideband point radiation source;
(b) producing an in-focus reference beam;
(c) producing antisymmetric spatial properties in the in-focus reference beam;
(d) passing the probe beam through a dispersal element to convert the probe beam to a beam focused to a target line;
(e) producing an in-focus return probe beam;
(f) producing antisymmetric spatial properties in the in-focus return probe beam;
(g) spatially filtering the in-focus return probe beam;
(h) passing the spatially filtered in-focus return probe beam through a dispersal element to convert it to a beam focused to a line in a detector plane of a detector;
(i) spatially filtering the in-focus reference beam;
(j) passing the spatially filtered in-focus reference beam through a dispersal element to convert it to a beam focused to the line in the detector plane;
(k) spatially filtering a beam from a plurality of out-of-focus image points;
(l) passing the spatially filtered beam from the plurality of out-of-focus image points through a dispersal element;
(m) interfering the spatially filtered in-focus reference beam with the spatially filtered beam from the out-of-focus image points;
(n) interfering the spatially filtered in-focus reference beam with the spatially filtered in-focus return probe beam;
and
(o) reducing systematic and statistical errors in data produced by a detector to represent the information being determined by detecting the complex amplitude of the spatially filtered in-focus return probe beam as interference data by means of detector elements of the detector wherein the interference data comprises an interference term between the spatially filtered in-focus reference beam and the spatially filtered in-focus return probe beam and another interference term of a substantially reduced amplitude between the spatially filtered beam from the plurality of out-of-focus image points and the spatially filtered in-focus reference beam.

13 more elements

A method for discriminating an in-focus image from an out-of-focus image so as to reduce errors in determining information represented by information representative of the in-focus image, comprising the steps of:

(a) producing a probe beam and a reference beam from a wideband point radiation source;
(b) producing an in-focus reference beam;
(c) producing antisymmetric spatial properties in the in-focus reference beam;
(d) converting the probe beam to a beam focused to a target line;
(e) producing an in-focus return probe beam;
(f) producing antisymmetric spatial properties in the in-focus return probe beam;
(g) spatially filtering the in-focus return probe beam;
(h) converting the spatially filtered in-focus return probe beam to a beam focused to a line in a detector plane of a detector;
(i) spatially filtering the in-focus reference beam;
(j) converting the spatially filtered in-focus reference beam to a beam focused to the line in the detector plane;
(k) spatially filtering a beam from a plurality of out-of-focus image points;
(l) interfering the converted spatially filtered in-focus reference beam with the spatially filtered beam from the plurality of out-of-focus image points;
(m) interfering the converted spatially filtered in-focus reference beam with the converted spatially filtered in-focus return probe beam;
and
(n) reducing errors in data produced by the detector to represent the information being determined by detecting by means of the detector the spatially filtered in-focus return probe beam as interference data comprising an interference term between the converted spatially filtered in-focus reference beam and the converted spatially filtered in-focus return probe beam and another interference term of substantially reduced amplitude between the spatially filtered beam from the plurality of out-of-focus image points and the converted spatially filtered in-focus reference beam.

12 more elements

A system for use in profiling the surface of a wafer, the system comprising:

(a) a stage for supporting the wafer;
(b) an illumination system for imaging spatially patterned radiation onto the wafer;
(c) a gauged positioning control system for adjusting the position of the stage relative to the imaged radiation;
(d) an interferometry system for measuring the position of the wafer relative to the imaged radiation;
and
(e) an identification mark sub-system for identifying an alignment mark in an information-bearing region, the identification mark sub-system including means for discriminating an in-focus image of an information-bearing region in and/or on a substance from an out-of-focus image so as to reduce errors in determining information represented by the information-bearing region in and/or on the substance, the discriminating means including
(1) means for producing a probe beam and a reference beam from an array of monochromatic point radiation sources,
(2) means for producing an in-focus return probe beam by directing the probe beam to an array of in-focus image points,
(3) means for producing antisymmetric spatial properties in the in-focus return probe beam,
(4) means for producing an in-focus reference beam,
(5) means for producing antisymmetric spatial properties in the in-focus reference beam,
(6) means for interfering the in-focus reference beam with a beam from a plurality of out-of-focus image points,
(7) means for interfering the in-focus reference beam with the in-focus return probe beam, and
(8) means for reducing systematic and statistical errors in data produced by a detector to represent the information being determined by detecting the complex amplitude of the in-focus return probe beam as interference data by means of detector elements of the detector wherein the interference data comprises an interference term between the in-focus reference beam and the in-focus return probe beam and another interference term of substantially reduced amplitude between the out-of-focus image beams associated with out-of-focus image points and corresponding portions of the in-focus reference beam.

11 more elements

A metrology system for use in measuring defects in a mask to be used in fabrication of an integrated circuit, the metrology system comprising:

(a) a gauge-controlled stage for supporting the mask;
(b) a microscope system for imaging the mask and producing a first digital representation of pattern features of the mask, the microscope system including
(1) means for producing a probe beam and a reference beam from an array of monochromatic point radiation sources,
(2) means for producing an in-focus return probe beam by directing the probe beam to an array of in-focus image points,
(3) means for producing antisymmetric spatial properties in the in-focus return probe beam,
(4) means for producing an in-focus reference beam,
(5) means for producing antisymmetric spatial properties in the in-focus reference beam,
(6) means for interfering the in-focus reference beam with a beam from a plurality of out-of-focus image points,
(7) means for interfering the in-focus reference beam with the in-focus return probe beam, and
(8) means for reducing systematic and statistical errors in data produced by a detector to represent information being determined by detecting the complex amplitude of the in-focus return probe beam as interference data by means of detector elements of the detector wherein the interference data comprises an interference term between the in-focus reference beam and the in-focus return probe beam and another interference term of substantially reduced amplitude between the out-of-focus image beams associated with out-of-focus image points and corresponding portions of the in-focus reference beam;
(c) a memory system for storing an accurate second digital representation of the pattern features of the mask;
and
(d) a processor coupled to the memory system and the microscope system for comparing the first and second digital representations of the mask image to determine defects of the mask.

10 more elements

A system for producing an image of an information-bearing region with reduced sensitivity to motion of a substance containing the information-bearing region, the system comprising:

(a) a support structure supporting the substance;
(b) a microscope system for imaging the information-bearing region, the microscope system including
(1) means for producing a probe beam and a reference beam from an array of monochromatic point radiation sources,
(2) means for producing an in-focus return probe beam by directing the probe beam to an array of in-focus image points,
(3) means for producing antisymmetric spatial properties in the in-focus return probe beam,
(4) means for producing an in-focus reference beam,
(5) means for producing antisymmetric spatial properties in the in-focus reference beam,
(6) means for interfering the in-focus reference beam with a beam from a plurality of out-of-focus image points,
(7) means for interfering the in-focus reference beam with the in-focus return probe beam, and
(8) means for reducing systematic and statistical errors in data produced by a detector to represent information being determined by detecting the complex amplitude of the in-focus return probe beam as interference data by means of detector elements of the detector wherein the interference data comprises an interference term between the in-focus reference beam and the in-focus return probe beam and another interference term of substantially reduced amplitude between the out-of-focus image beams associated with out-of-focus image points and corresponding portions of the in-focus reference beam,
wherein a predetermined one-dimensional or two-dimensional section of the information-bearing region produced by the microscope system is substantially independent of motion of the substance relative to the microscope system.

8 more elements

A system for producing an image of an information bearing surface of a substance having an external surface to control a spatial relationship between the system and the external surface, the system comprising;

a) a support structure supporting the substance;
b) a microscope system for imaging the profile of the external surface and determining the spatial relationship between the external surface and the system, the microscope system including
(1) means for producing a probe beam and a reference beam from an array of monochromatic point radiation sources,
(2) means for producing an in-focus return probe beam by directing the probe beam to an array of in-focus image points,
(3) means for producing antisymmetric spatial properties in the in-focus return probe beam,
(4) means for producing an in-focus reference beam,
(5) means for producing antisymmetric spatial properties in the in-focus reference beam,
(6) means for interfering the in-focus reference beam with a beam from a plurality of out-of-focus image points,
(7) means for interfering the in-focus reference beam with the in-focus return probe beam, and
(8) means for reducing systematic and statistical errors in data produced by a detector to represent information being determined by detecting the complex amplitude of the in-focus return probe beam as interference data by means of detector elements of the detector wherein the interference data comprises an interference term between the in-focus reference beam and the in-focus return probe beam and another interference term of substantially reduced amplitude between the out-of-focus image beams associated with out-of-focus image points and corresponding portions of the in-focus reference beam;
and
c) a processor controlling the location of the microscope system relative to the external surface in accordance with the determined spatial relationship to prevent physical contact of the microscope system with the external surface.

9 more elements

A system for use in fabricating integrated circuitry on a wafer, the system comprising:

(a) a stage for supporting the wafer;
(b) an illumination system for imaging spatially patterned radiation onto the wafer;
(c) a gauged positioning control system for adjusting the position of the stage relative to the imaged radiation;
(d) an interferometry system for measuring the position of the wafer relative to the imaged radiation;
and
(e) an identification mark sub-system for identifying an alignment mark in an information-bearing region, the identification mark sub-system including means for discriminating an in-focus image of an information-bearing region in and/or on a substance from an out-of-focus image so as to reduce errors in determining information represented by the information-bearing region in and/or on the substance, the discriminating means including
(1) means for producing a probe beam and a reference beam from a wideband point radiation source,
(2) means for producing an in-focus reference beam,
(3) means for producing antisymmetric spatial properties in the in-focus reference beam,
(4) means for passing the probe beam through a dispersal element to convert the probe beam to a beam focused to a target line in the information-bearing region,
(5) means for producing an in-focus return probe beam,
(6) means for producing antisymmetric spatial properties in the in-focus return probe beam,
(7) means for spatially filtering the in-focus return probe beam,
(8) means for passing the spatially filtered in-focus return probe beam through a dispersal element to convert it to a beam focused to a line in a detector plane of a detector,
(9) means for spatially filtering the in-focus reference beam,
(10) means for passing the spatially filtered in-focus reference beam through a dispersal element to convert it to a beam focused to the line in the detector plane,
(11) means for spatially filtering a beam from a plurality of out-of-focus image points,
(12) means for passing the spatially filtered beam from the plurality of out-of-focus image points through a dispersal element,
(13) means for interfering the spatially filtered in-focus reference beam with the spatially filtered beam from the out-of-focus image points,
(14) means for interfering the spatially filtered in-focus reference beam with the spatially filtered in-focus return probe beam, and
(15) means for reducing systematic and statistical errors in data produced by a detector to represent information being determined by detecting the complex amplitude of the spatially filtered in-focus return probe beam as interference data by means of detector elements of the detector wherein the interference data comprises an interference term between the spatially filtered in-focus reference beam and the spatially filtered in-focus return probe beam and another interference term of a substantially reduced amplitude between the spatially filtered beam from the plurality of out-of-focus image points and the spatially filtered in-focus reference beam.

18 more elements

A metrology system for use in measuring overlay accuracy of a lithography stepper or scanner in fabricating an integrated circuit on a wafer, the metrology system comprising:

(a) a gauge-controlled stage for measuring the relative positions of a first pattern in a first information-bearing region on a first level of the integrated circuit and a second pattern in a second information-bearing region on a second level of the integrated circuit;
(b) a wafer handling system including the stage, for supporting the wafer;
and
(c) a microscope system for viewing the patterns, the microscope system including
(1) means for producing a probe beam and a reference beam from a wideband point radiation source,
(2) means for producing an in-focus reference beam,
(3) means for producing antisymmetric spatial properties in the in-focus reference beam,
(4) means for passing the probe beam through a dispersal element to convert the probe beam to a beam focused to a target line in the information-bearing region,
(5) means for producing an in-focus return probe beam,
(6) means for producing antisymmetric spatial properties in the in-focus return probe beam,
(7) means for spatially filtering the in-focus return probe beam,
(8) means for passing the spatially filtered in-focus return probe beam through a dispersal element to convert it to a beam focused to a line in a detector plane of a detector,
(9) means for spatially filtering the in-focus reference beam,
(10) means for passing the spatially filtered in-focus reference beam through a dispersal element to convert it to a beam focused to the line in the detector plane,
(11) means for spatially filtering a beam from a plurality of out-of-focus image points,
(12) means for passing the spatially filtered beam from the plurality of out-of-focus image points through a dispersal element,
(13) means for interfering the spatially filtered in-focus reference beam with the spatially filtered beam from the out-of-focus image points,
(14) means for interfering the spatially filtered in-focus reference beam with the spatially filtered in-focus return probe beam, and
(15) means for reducing systematic and statistical errors in data produced by a detector to represent information being determined by detecting the complex amplitude of the spatially filtered in-focus return probe beam as interference data by means of detector elements of the detector wherein the interference data comprises an interference term between the spatially filtered in-focus reference beam and the spatially filtered in-focus return probe beam and another interference term of a substantially reduced amplitude between the spatially filtered beam from the plurality of out-of-focus image points and the spatially filtered in-focus reference beam.

16 more elements

A metrology system for use in measuring defects in a mask to be used in fabrication of an integrated circuit, the metrology system comprising:

(a) a gauge-controlled stage for supporting the mask;
(b) a microscope system for imaging the mask and producing a first digital representation of pattern features of the mask, the microscope system including
(1) means for producing a probe beam and a reference beam from a wideband point radiation source,
(2) means for producing an in-focus reference beam,
(3) means for producing antisymmetric spatial properties in the in-focus reference beam,
(4) means for passing the probe beam through a dispersal element to convert the probe beam to a beam focused to a target line in the information-bearing region,
(5) means for producing an in-focus return probe beam,
(6) means for producing antisymmetric spatial properties in the in-focus return probe beam,
(7) means for spatially filtering the in-focus return probe beam,
(8) means for passing the spatially filtered in-focus return probe beam through a dispersal element to convert it to a beam focused to a line in a detector plane of a detector,
(9) means for spatially filtering the in-focus reference beam,
(10) means for passing the spatially filtered in-focus reference beam through a dispersal element to convert it to a beam focused to the line in the detector plane,
(11) means for spatially filtering a beam from a plurality of out-of-focus image points,
(12) means for passing the spatially filtered beam from the plurality of out-of-focus image points through a dispersal element,
(13) means for interfering the spatially filtered in-focus reference beam with the spatially filtered beam from the out-of-focus image points,
(14) means for interfering the spatially filtered in-focus reference beam with the spatially filtered in-focus return probe beam, and
(15) means for reducing systematic and statistical errors in data produced by a detector to represent information being determined by detecting the complex amplitude of the spatially filtered in-focus return probe beam as interference data by means of detector elements of the detector wherein the interference data comprises an interference term between the spatially filtered in-focus reference beam and the spatially filtered in-focus return probe beam and another interference term of a substantially reduced amplitude between the spatially filtered beam from the plurality of out-of-focus image points and the spatially filtered in-focus reference beam;
(c) a memory system for storing an accurate second digital representation of the pattern features of the mask;
and
(d) a processor coupled to the memory system and the microscope system for comparing the first and second digital representations of the mask image to determine defects of the mask.

17 more elements

A system for producing an image of an information-bearing region, with reduced sensitivity to motion of a substance containing the information-bearing region, the system comprising:

(a) a support structure supporting the substance;
(b) a microscope system for imaging the information-bearing region, the microscope system including
(1) means for producing a probe beam and a reference beam from a wideband point radiation source,
(2) means for producing an in-focus reference beam,
(3) means for producing antisymmetric spatial properties in the in-focus reference beam,
(4) means for passing the probe beam through a dispersal element to convert the probe beam to a beam focused to a target line in the information-bearing region,
(5) means for producing an in-focus return probe beam,
(6) means for producing antisymmetric spatial properties in the in-focus return probe beam,
(7) means for spatially filtering the in-focus return probe beam,
(8) means for passing the spatially filtered in-focus return probe beam through a dispersal element to convert it to a beam focused to a line in a detector plane of a detector,
(9) means for spatially filtering the in-focus reference beam,
(10) means for passing the spatially filtered in-focus reference beam through a dispersal element to convert it to a beam focused to the line in the detector plane,
(11) means for spatially filtering a beam from a plurality of out-of-focus image points,
(12) means for passing the spatially filtered beam from the plurality of out-of-focus image points through a dispersal element,
(13) means for interfering the spatially filtered in-focus reference beam with the spatially filtered beam from the out-of-focus image points,
(14) means for interfering the spatially filtered in-focus reference beam with the spatially filtered in-focus return probe beam, and
(15) means for reducing systematic and statistical errors in data produced by a detector to represent information being determined by detecting the complex amplitude of the spatially filtered in-focus return probe beam as interference data by means of detector elements of the detector wherein the interference data comprises an interference term between the spatially filtered in-focus reference beam and the spatially filtered in-focus return probe beam and another interference term of a substantially reduced amplitude between the spatially filtered beam from the plurality of out-of-focus image points and the spatially filtered in-focus reference beam,
wherein a predetermined one-dimensional or two-dimensional section of the information-bearing region produced by the microscope system is substantially independent of motion of the substance relative to the microscope system.

15 more elements

A system for producing an image of an information bearing surface of a substance having an external surface to control a spatial relationship between the system and the external surface, the system comprising;

a) a support structure supporting the substance;
b) a microscope system for imaging the profile of the external surface and determining the spatial relationship between the external surface and the system, the microscope system including
(1) means for producing a probe beam and a reference beam from a wideband point radiation source,
(2) means for producing an in-focus reference beam,
(3) means for producing antisymmetric spatial properties in the in-focus reference beam,
(4) means for passing the probe beam through a dispersal element to convert the probe beam to a beam focused to a target line in the information-bearing region,
(5) means for producing an in-focus return probe beam,
(6) means for producing antisymmetric spatial properties in the in-focus return probe beam,
(7) means for spatially filtering the in-focus return probe beam,
(8) means for passing the spatially filtered in-focus return probe beam through a dispersal element to convert it to a beam focused to a line in a detector plane of a detector,
(9) means for spatially filtering the in-focus reference beam,
(10) means for passing the spatially filtered in-focus reference beam through a dispersal element to convert it to a beam focused to the line in the detector plane,
(11) means for spatially filtering a beam from a plurality of out-of-focus image points,
(12) means for passing the spatially filtered beam from the plurality of out-of-focus image points through a dispersal element,
(13) means for interfering the spatially filtered in-focus reference beam with the spatially filtered beam from the out-of-focus image points,
(14) means for interfering the spatially filtered in-focus reference beam with the spatially filtered in-focus return probe beam, and
(15) means for reducing systematic and statistical errors in data produced by a detector to represent information being determined by detecting the complex amplitude of the spatially filtered in-focus return probe beam as interference data by means of detector elements of the detector wherein the interference data comprises an interference term between the spatially filtered in-focus reference beam and the spatially filtered in-focus return probe beam and another interference term of a substantially reduced amplitude between the spatially filtered beam from the plurality of out-of-focus image points and the spatially filtered in-focus reference beam;
and
c) a processor controlling the location of the microscope system relative to the external surface in accordance with the determined spatial relationship to prevent physical contact of the microscope system with the external surface.

16 more elements

A system for use in fabricating integrated circuitry on a wafer, the system comprising:

(a) a stage for supporting the wafer;
(b) an illumination system for imaging spatially patterned radiation onto the wafer;
(c) a gauged positioning control system for adjusting the position of the stage relative to the imaged radiation;
(d) an interferometry system for measuring the position of the wafer relative to the imaged radiation;
and
(e) an identification mark sub-system for identifying an alignment mark in an information-bearing region, the identification mark sub-system including means for discriminating an in-focus image of an information-bearing region in and/or on a substance from an out-of-focus image so as to reduce errors in determining information represented by the information-bearing region in and/or on the substance, the discriminating means including
(1) means for producing a probe beam and a reference beam from a wideband point radiation source,
(2) means for producing an in-focus reference beam,
(3) means for producing antisymmetric spatial properties in the in-focus reference beam,
(4) means for converting the probe beam to a beam focused to a target line in the information-bearing region,
(5) means for producing an in-focus return probe beam,
(6) means for producing antisymmetric spatial properties in the in-focus return probe beam,
(7) means for spatially filtering the in-focus return probe beam,
(8) means for converting the spatially filtered in-focus return probe beam to a beam focused to a line in a detector plane of a detector,
(9) means for spatially filtering the in-focus reference beam,
(10) means for converting the spatially filtered in-focus reference beam to a beam focused to the line in the detector plane,
(11) means for spatially filtering a beam from a plurality of out-of-focus image points,
(12) means for interfering the converted spatially filtered in-focus reference beam with the spatially filtered beam from the plurality of out-of-focus image points,
(13) means for interfering the converted spatially filtered in-focus reference beam with the converted spatially filtered in-focus return probe beam, and
(14) means for reducing errors in data produced by the detector to represent information being determined by detecting by means of the detector the spatially filtered in-focus return probe beam as interference data comprising an interference term between the converted spatially filtered in-focus reference beam and the converted spatially filtered in-focus return probe beam and another interference term of substantially reduced amplitude between the spatially filtered beam from the plurality of out-of-focus image points and the converted spatially filtered in-focus reference beam.

17 more elements

A metrology system for use in measuring overlay accuracy of a lithography stepper or scanner in fabricating an integrated circuit on a wafer, the metrology system comprising:

(a) a gauge-controlled stage for measuring the relative positions of a first pattern in a first information-bearing region on a first level of the integrated circuit and a second pattern in a second information-bearing region on a second level of the integrated circuit;
(b) a wafer handling system including the stage, for supporting the wafer;
and
(c) a microscope system for viewing the patterns to compare the relative positions of the first pattern and the second pattern, the microscope system including
(1) means for producing a probe beam and a reference beam from a wideband point radiation source,
(2) means for producing an in-focus reference beam,
(3) means for producing antisymmetric spatial properties in the in-focus reference beam,
(4) means for converting the probe beam to a beam focused to a target line in the information-bearing region,
(5) means for producing an in-focus return probe beam,
(6) means for producing antisymmetric spatial properties in the in-focus return probe beam,
(7) means for spatially filtering the in-focus return probe beam,
(8) means for converting the spatially filtered in-focus return probe beam to a beam focused to a line in a detector plane of a detector,
(9) means for spatially filtering the in-focus reference beam,
(10) means for converting the spatially filtered in-focus reference beam to a beam focused to the line in the detector plane,
(11) means for spatially filtering a beam from a plurality of out-of-focus image points,
(12) means for interfering the converted spatially filtered in-focus reference beam with the spatially filtered beam from the plurality of out-of-focus image points,
(13) means for interfering the converted spatially filtered in-focus reference beam with the converted spatially filtered in-focus return probe beam, and
(14) means for reducing errors in data produced by the detector to represent information being determined by detecting by means of the detector the spatially filtered in-focus return probe beam as interference data comprising an interference term between the converted spatially filtered in-focus reference beam and the converted spatially filtered in-focus return probe beam and another interference term of substantially reduced amplitude between the spatially filtered beam from the plurality of out-of-focus image points and the converted spatially filtered in-focus reference beam.

15 more elements

A metrology system for use in measuring defects in a mask to be used in fabrication of an integrated circuit, the metrology system comprising:

(a) a gauge-controlled stage for supporting the mask;
(b) a microscope system for imaging the mask and producing a first digital representation of pattern features of pattern features of the mask, the microscope system including
(1) means for producing a probe beam and a reference beam from a wideband point radiation source,
(2) means for producing an in-focus reference beam,
(3) means for producing antisymmetric spatial properties in the in-focus reference beam,
(4) means for converting the probe beam to a beam focused to a target line in the information-bearing region,
(5) means for producing an in-focus return probe beam,
(6) means for producing antisymmetric spatial properties in the in-focus return probe beam,
(7) means for spatially filtering the in-focus return probe beam,
(8) means for converting the spatially filtered in-focus return probe beam to a beam focused to a line in a detector plane of a detector,
(9) means for spatially filtering the in-focus reference beam,
(10) means for converting the spatially filtered in-focus reference beam to a beam focused to the line in the detector plane,
(11) means for spatially filtering a beam from a plurality of out-of-focus image points,
(12) means for interfering the converted spatially filtered in-focus reference beam with the spatially filtered beam from the plurality of out-of-focus image points,
(13) means for interfering the converted spatially filtered in-focus reference beam with the converted spatially filtered in-focus return probe beam, and
(14) means for reducing errors in data produced by the detector to represent information being determined by detecting by means of the detector the spatially filtered in-focus return probe beam as interference data comprising an interference term between the converted spatially filtered in-focus reference beam and the converted spatially filtered in-focus return probe beam and another interference term of substantially reduced amplitude between the spatially filtered beam from the plurality of out-of-focus image points and the converted spatially filtered in-focus reference beam;
(c) a memory system for storing an accurate second digital representation of the pattern features of the mask;
and
(d) a processor coupled to the memory system and the microscope system for comparing the first and second digital representations of the mask image to determine defects of the mask.

16 more elements

A system for producing an image of an information-bearing region, with reduced sensitivity to motion of a substance containing the information-bearing region, the system comprising:

(a) a support structure supporting the substance;
(b) a microscope system for imaging the information-bearing region, the microscope system including
(1) means for producing a probe beam and a reference beam from a wideband point radiation source,
(2) means for producing an in-focus reference beam,
(3) means for producing antisymmetric spatial properties in the in-focus reference beam,
(4) means for converting the probe beam to a beam focused to a target line in the information-bearing region,
(5) means for producing an in-focus return probe beam,
(6) means for producing antisymmetric spatial properties in the in-focus return probe beam,
(7) means for spatially filtering the in-focus return probe beam,
(8) means for converting the spatially filtered in-focus return probe beam to a beam focused to a line in a detector plane of a detector,
(9) means for spatially filtering the in-focus reference beam,
(10) means for converting the spatially filtered in-focus reference beam to a beam focused to the line in the detector plane,
(11) means for spatially filtering a beam from a plurality of out-of-focus image points,
(12) means for interfering the converted spatially filtered in-focus reference beam with the spatially filtered beam from the plurality of out-of-focus image points,
(13) means for interfering the converted spatially filtered in-focus reference beam with the converted spatially filtered in-focus return probe beam, and
(14) means for reducing errors in data produced by the detector to represent information being determined by detecting by means of the detector the spatially filtered in-focus return probe beam as interference data comprising an interference term between the converted spatially filtered in-focus reference beam and the converted spatially filtered in-focus return probe beam and another interference term of substantially reduced amplitude between the spatially filtered beam from the plurality of out-of-focus image points and the converted spatially filtered in-focus reference beam,
wherein a predetermined one-dimensional or two-dimensional section of the information-bearing region produced by the microscope system is substantially independent of motion of the substance relative to the microscope system.

14 more elements

A system for producing an image of an information surface of a substance having an external surface to control a spatial relationship between the system and the external surface, the system comprising;

a) a support structure supporting the substance;
b) a microscope system for imaging the profile of the external surface and determining the spatial relationship between the external surface and the system, the microscope system including
(1) means for producing a probe beam and a reference beam from a wideband point radiation source,
(2) means for producing an in-focus reference beam,
(3) means for producing antisymmetric spatial properties in the in-focus reference beam,
(4) means for converting the probe beam to a beam focused to a target line in the information-bearing region,
(5) means for producing an in-focus return probe beam,
(6) means for producing antisymmetric spatial properties in the in-focus return probe beam,
(7) means for spatially filtering the in-focus return probe beam,
(8) means for converting the spatially filtered in-focus return probe beam to a beam focused to a line in a detector plane of a detector,
(9) means for spatially filtering the in-focus reference beam,
(10) means for converting the spatially filtered in-focus reference beam to a beam focused to the line in the detector plane,
(11) means for spatially filtering a beam from a plurality of out-of-focus image points,
(12) means for interfering the converted spatially filtered in-focus reference beam with the spatially filtered beam from the plurality of out-of-focus image points,
(13) means for interfering the converted spatially filtered in-focus reference beam with the converted spatially filtered in-focus return probe beam, and
(14) means for reducing errors in data produced by the detector to represent information being determined by detecting by means of the detector the spatially filtered in-focus return probe beam as interference data comprising an interference term between the converted spatially filtered in-focus reference beam and the converted spatially filtered in-focus return probe beam and another interference term of substantially reduced amplitude between the spatially filtered beam from the plurality of out-of-focus image points and the converted spatially filtered in-focus reference beam;
and
c) a processor controlling the location of the microscope system relative to the external surface in accordance with the determined spatial relationship to prevent physical contact of the microscope system with the external surface.

15 more elements

A method for discriminating an in-focus image of an information-bearing region in and/or on a substance from an out-of-focus image so as to reduce errors in determining information represented by the information-bearing region in and/or on the substance, comprising the steps of:

(a) producing a probe beam and a reference beam from a wideband point radiation source;
(b) producing an in-focus reference beam;
(c) producing antisymmetric spatial properties in the in-focus reference beam;
(d) passing the probe beam through a dispersal element to convert the probe beam to a beam focused to a target line in the information-bearing region;
(e) producing an in-focus return probe beam;
(f) producing antisymmetric spatial properties in the in-focus return probe beam;
(g) spatially filtering the in-focus return probe beam;
(h) passing the spatially filtered in-focus return probe beam through a dispersal element to convert it to a beam focused to a line in a detector plane of a detector;
(i) spatially filtering the in-focus reference beam;
(j) passing the spatially filtered in-focus reference beam through a dispersal element to convert it to a beam focused to the line in the detector plane;
(k) spatially filtering a beam from a plurality of out-of-focus image points;
(l) passing the spatially filtered beam from the plurality of out-of-focus image points through a dispersal element;
(m) interfering the spatially filtered in-focus reference beam with the spatially filtered beam from the out-of-focus image points;
(n) interfering the spatially filtered in-focus reference beam with the spatially filtered in-focus return probe beam;
and
(o) reducing systematic and statistical errors in data produced by a detector to represent the information being determined by detecting the complex amplitude of the spatially filtered in-focus return probe beam as interference data by means of detector elements of the detector wherein the interference data comprises an interference term between the spatially filtered in-focus reference beam and the spatially filtered in-focus return probe beam and another interference term of a substantially reduced amplitude between the spatially filtered beam from the plurality of out-of-focus image points and the spatially filtered in-focus reference beam.

13 more elements

A method for discriminating an in-focus image of an information-bearing region in and/or on a substance from an out-of-focus image so as to reduce errors in determining information represented by the information-bearing region in and/or on the substance, comprising the steps of:

(a) producing a probe beam and a reference beam from a wideband point radiation source;
(b) producing an in-focus reference beam;
(c) producing antisymmetric spatial properties in the in-focus reference beam;
(d) converting the probe beam to a beam focused to a target line in the information-bearing region;
(e) producing an in-focus return probe beam;
(f) producing antisymmetric spatial properties in the in-focus return probe beam;
(g) spatially filtering the in-focus return probe beam;
(h) converting the spatially filtered in-focus return probe beam to a beam focused to a line in a detector plane of a detector;
(i) spatially filtering the in-focus reference beam;
(j) converting the spatially filtered in-focus reference beam to a beam focused to the line in the detector plane;
(k) spatially filtering a beam from a plurality of out-of-focus image points;
(l) interfering the converted spatially filtered in-focus reference beam with the spatially filtered beam from the plurality of out-of-focus image points;
(m) interfering the converted spatially filtered in-focus reference beam with the converted spatially filtered in-focus return probe beam;
and
(n) reducing errors in data produced by the detector to represent the information being determined by detecting by means of the detector the spatially filtered in-focus return probe beam as interference data comprising an interference term between the converted spatially filtered in-focus reference beam and the converted spatially filtered in-focus return probe beam and another interference term of substantially reduced amplitude between the spatially filtered beam from the plurality of out-of-focus image points and the converted spatially filtered in-focus reference beam.

12 more elements

Multiple layer confocal interference microscopy using wavenumber domain reflectometry and background amplitude reduction and compensation

Life of this patent

Multiple layer confocal interference microscopy using wavenumber domain reflectometry and background amplitude reduction and compensation

Life of this patent

Abstract

Claims92