Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/47—Scattering, i.e. diffuse reflection
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/70—Microphotolithographic exposure; Apparatus therefor
  • G03F7/70691—Handling of masks or workpieces
  • G03F7/70791—Large workpieces, e.g. glass substrates for flat panel displays or solar panels
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B11/00—Measuring arrangements characterised by the use of optical techniques
  • G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness

Definitions

• This invention relates to the use of light in determining the characteristics of objects, especially dimensional information about relatively small features in flat-panel cathode-ray tube (“CRT”) displays.
• CTR cathode-ray tube
• the light-emitting device in a field-emission display contains a transparent faceplate, an anode that overlies the faceplate's interior surface, and an array of light-emitting regions also overlying the faceplate's interior surface.
• FED field-emission display
• electrons are emitting from selected electron- emissive elements and are attracted by the anode to the light-emitting device.
• the electrons Upon reaching the light- emitting device, the electrons strike corresponding light-emissive regions and cause them to emit light that produces an image on the faceplate's exterior surface.
• An analytical system that implements the light- scattering or light-transmission technique of the invention contains a light-emitting structure, a light- collecting structure, and a processor.
• the light- emitting structure provides light which is transmitted through the openings or/and undergoes scattering in being propagated into the openings.
• the light- collecting structure collects the transmitted or scattered light, and provides the light-collection signal.
• the processor evaluates the light-collection signal to determine the desired dimensional information.
• Fig. 16 is a view of a diffraction pattern produced by an object, such as the electron-emitting device of Fig. 2f, having one or more line abnormalities .
• Field emitter 10 consists of a generally flat electrically insulating baseplate 20 and a group of patterned layers 22 overlying the interior surface of baseplate 20.
• Light-emitting device 12 consists of a generally flat transparent faceplate 24 and a group of patterned layers 26 overlying the interior surface of faceplate 24.
• Baseplate 20 and faceplate 24 extend largely parallel to each other.
• the areal track density is usually in the range of 10 6 - 10 9 tracks/cm 2 , typically 10 8 tracks/cm 2 .
• Track layer 40 is brought into contact with a suitable chemical etchant that attacks the damaged material along charged-particle tracks 44 much more than the undamaged material of layer 40.
• Track pores 46 are thereby formed through layer 40 at the locations of tracks 44. See Fig. 2c in which item 40A is the remainder of layer 40.
• Some of the undamaged material along tracks 44 is normally removed.
• the etchant also normally attacks the track material along the upper surface of layer 40 so as to reduce its thickness. For simplicity, this thickness reduction is not shown in Fig. 2c.
• Portions of tracks 44 that extend beyond track layer 40A do not serve any useful function here and are not further illustrated in the drawings.
• Light-collecting element 72 provides a composite signal 82 representative of the intensity of transmitted light 78.
• composite signal 82 is normally a sequence of data corresponding to the image formed by transmitted light 78.
• Light-collecting element 72 may include a light filter that substantially attenuates light of wavelength less than principal value ⁇ p. The filter is placed between object 60 and the light collector in element 72. Alternatively, element 72 may be responsive substantially only to transmitted light 78 of wavelength greater than ⁇ P . In such cases, composite signal 82 does not have a signal component arising from light of wavelength less than ⁇ P .
• the short-wavelength light can be provided by element 70 or by another light-emitting element in the light-emitting structure that contains element 70.
• the short-wavelength light can be collected by primary light-collecting element 72 or by another light-collecting element in the light- collecting structure that contains element 72.
• the light-collecting element (however implemented) provides data processor 74 with a composite signal representative of the intensity of the collected short- wavelength light.
• the wavelength for emitted light 76, and thus the wavelength for transmitted light 78 is controlled in such a way as to be close to the long wavelength limit where ratio d/ ⁇ is much less than 1.
• FIGs. 7 and 8 illustrate a pair of analytical systems that employ a light-scattering technique in accordance with the invention for determining dimensional information about object 60.
• the dimensional information again typically includes average diameter d AV of openings 62 in perforated layer 64.
• the analytical systems of Figs. 7 and 8 are configured largely the same and operate in largely the same manner. For convenience, the analytical systems of Figs. 7 and 8 are discussed together in the following material.
• the analytical system of each of Figs. 7 and 8 contains a data processor 108 that evaluates composite signal 106 to determine the desired dimensional information.
• Data processor 108 is typically located at a substantial distance away from the remainder of the system of Fig. 7 or 8 but may be in close proximity to the remainder of the system.
• Processor 108 may be the same physical hardware as processor 74.
• the intensity I s of light which undergoes scattering as the light encounters a surface is, as a function of wavelength ⁇ , the product of emitted light intensity I E and a scattering factor F s .
• Fig. 10 illustrates how scattering factor F s varies with wavelength ⁇ as a function of the feature size that causes the light scattering. As Fig. 10 indicates, scattering factor F ⁇ decreases with increasing wavelength ⁇ . Factor F s also increases as the size of the light-scattering feature increases. When the light-scattering feature is the edge of an opening, the size of the feature is determined by the perimeter of the opening. Since the perimeter of an opening is proportional to its diameter, factor F s for openings 62 increases with increasing average d AV at a given value of wavelength ⁇ .
• the horizontal axis represents the ratio of average diameter d AV of openings 62 to the wavelength ⁇ of scattered light 100 or 104 for the situation in which light 100 or 104 is substantially at wavelength ⁇ .
• the word "corrected” is employed in describing ratio d AV / ⁇ in Fig. 12 to reflect the fact that correction is made in composite signal 106 for error that arises, for example, due to the passage of light 100 or 104 through body 68.
• the vertical axis in Fig. 12 presents the normalized intensity factor Is/Iso for scattered light 100 or 104.
• Parameter I s here is specifically the intensity of scattered light 100 or 104 along the exterior surface of body 68.
• Parameter I S o is the average intensity that scattered light 100 or 104 would have along the exterior surface of body 68 at the short-wavelength limit of geometric optics, i.e., as wavelength ⁇ goes to zero.
• the wavelength for emitted light 76 and thus the wavelength for scattered light 100 or 104, is controlled so as to be close to the long-wavelength limit where ratio d AV / ⁇ is much less than 1.
• Figs. 13 and 14 depict a pair of analytical systems that utilize a combined light-transmission/ light-scattering technique in accordance with the invention for determining dimensional information about object 60.
• the dimensional information typically includes the average thickness of perforated layer 64 in object 60.
• the analytical systems of Figs. 13 and 14 are configured largely the same and operate in largely the same manner. For convenience, the analytical systems of Figs. 13 and 14 are described together in the following material.
• the light-based analytical system of each of Figs. 13 and 14 contains a light-emitting structure and a light-collecting structure.
• object 60 and the light-emitting and light-collecting components of the light-emitting and light-collecting structures are situated in a very dark room.
• the light- emitting structure is depicted as including a further light-collecting element 130.
• the analytical system of Fig. 14 is arranged so that light-collecting elements 130 and 72 are situated over the same side of object 60 but with element 130 out of alignment with light- emitting element 70 through openings 62.
• element 130 is situated so as to avoid collecting a significant fraction of transmitted light 78. Instead, element 130 collects portion 100 of scattered light 80. In collecting scattered light 100, element 130 may be scanned over object 60.
• Light-collecting element 130 may be a separate light-collecting element from light-collecting element 72. If so, element 130 is typically implemented in the manner described above for element 72.
• the light-collecting structure in the analytical system of Fig. 13 or 14 provides composite signals 82 and 106.
• Composite signal 82 is again representative of the intensity of transmitted light 78.
• Light- collecting element 72 furnishes both of signals 82 and 106 in the system of Fig. 13.
• signal 106 is representative of the intensity of scattered light 126.
• Light-collecting elements 72 and 130 respectively provide signals 82 and 106 in the system of Fig. 14.
• signal 106 is representative of the intensity of scattered light 100.
• the present invention furnishes a technique in which light diffraction is utilized to determine certain characteristics of lines in which one group of the lines crosses another group of the lines.
• the characteristics determined according to this light- diffraction-based technique typically include information on the location of abnormalities such as defects.
• the present diffraction-based technique can be utilized to determine whether the defect is present solely in the upper group of lines or is present in both groups of lines.
• the order in which the light-diffraction patterns are produced is immaterial. Consider the simple case in which only one light-diffraction pattern is generated for lower lines 140 and in which only one light-diffraction pattern is generated for upper lines 142. Also assume that the diffraction pattern for lower lines 140 is generated before generating the diffraction pattern for upper lines 142.
• the abnormality may be a crossover or a non-crossover abnormality. Further examination of the object in Fig. 15 or the diffraction pattern for upper lines 142 may be needed to determine whether the abnormality is a crossover or non-crossover abnormality.
• Ludwig et al U.S. Patent 5,865,659 discloses how small, typically spherical, particles are employed in creating gate openings in FEDs.
• the analytical techniques of the invention can be applied to the FED fabrication processes in Ludwig et al .

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Analytical Chemistry (AREA)
• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)
• Length Measuring Devices By Optical Means (AREA)
• Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)

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Publications (1)

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• 1999
  • 1999-08-31 US US09/387,632 patent/US6392750B1/en not_active Expired - Fee Related
• 2000
  • 2000-08-22 WO PCT/US2000/023192 patent/WO2001016580A1/en not_active Ceased
  • 2000-08-22 EP EP00959338A patent/EP1212602A4/en not_active Withdrawn
  • 2000-08-22 JP JP2001520086A patent/JP4685306B2/ja not_active Expired - Fee Related
  • 2000-08-22 KR KR1020027002701A patent/KR20020067030A/ko not_active Withdrawn
  • 2000-08-22 AU AU70676/00A patent/AU7067600A/en not_active Abandoned
  • 2000-08-30 MY MYPI20004029 patent/MY133784A/en unknown
  • 2000-11-20 TW TW089117631A patent/TW548404B/zh not_active IP Right Cessation

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