US20060040109A1 - Thin film sol-gel derived glass - Google Patents

Thin film sol-gel derived glass Download PDF

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Publication number
US20060040109A1
US20060040109A1 US11110372 US11037205A US2006040109A1 US 20060040109 A1 US20060040109 A1 US 20060040109A1 US 11110372 US11110372 US 11110372 US 11037205 A US11037205 A US 11037205A US 2006040109 A1 US2006040109 A1 US 2006040109A1
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Prior art keywords
film
sol
gel
thin
glass
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Abandoned
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US11110372
Inventor
Edgar Mendoza
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Nagler Richard
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Optinetrics Inc
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    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES, OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C17/00Surface treatment of glass, not in the form of fibres or filaments, by coating
    • C03C17/02Surface treatment of glass, not in the form of fibres or filaments, by coating with glass
    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ELECTROGRAPHY; HOLOGRAPHY
    • G03FPHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/004Photosensitive materials
    • G03F7/0042Photosensitive materials with inorganic or organometallic light-sensitive compounds not otherwise provided for, e.g. inorganic resists
    • G03F7/0043Chalcogenides; Silicon, germanium, arsenic or derivatives thereof; Metals, oxides or alloys thereof
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES, OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2218/00Methods for coating glass
    • C03C2218/10Deposition methods
    • C03C2218/11Deposition methods from solutions or suspensions
    • C03C2218/113Deposition methods from solutions or suspensions by sol-gel processes
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES, OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2218/00Methods for coating glass
    • C03C2218/30Aspects of methods for coating glass not covered above
    • C03C2218/32After-treatment

Abstract

Thermally-assisted organometallic sol-gel derived glasses have been found to permit fabrication of thin films sufficiently thin for telecom components. Inclusion of a photosensitizer in the film permits light of controlled intensity to modify refractive indices in the film to form useful structures.

Description

    REFERENCE TO RELATED APPLICATIONS
  • [0001]
    This application is a continuation of U.S. patent application Ser. No. 09/574,841, filed May 19, 2000, which is hereby incorporated by reference in its entirety.
  • [0002]
    This application is also related to a companion application Ser. No. 09/574,840, filed on May 19, 2000, and assigned to the assignee of the present application.
  • FIELD OF INVENTION
  • [0003]
    This invention relates to a process for producing photosensitive thin films of sol-gel derived glass and to such films of a thickness useful for integrated optic devices produced thereby.
  • BACKGROUND OF THE INVENTION
  • [0004]
    The doctoral thesis by the application herein entitled “Photolithography of Integrated Optic Devices in Porous Glass,” City University of New York, 1992, describes an organometallic system of inclusions in a thermally-assisted, porous glass bulk material. The process for fabricating the glass requires introduction of a photosensitizer, exposure to light through a mask and two heat treatments. The doctoral thesis states that sol-gel techniques can be used to make the porous glass bulk material.
  • BRIEF DESCRIPTION OF THE INVENTION
  • [0005]
    The invention is based on the realization that the porous glass techniques for bulk materials using thermally assisted, organometallic, sol-gel derived glass can be extended to thin films suitable for telecom components and virtually free of lateral shrinkage. Consequently, a variety of highly desirable integrated optic components can be made by such a technique. Specifically, a technique for the photolithographic fabrication of integrated optic structures in thin films of photosensitive sol-gel glasses is described here. This technique involves the formation of a photosensitive sol-gel thin film including an organometallic photosensitizer, on a suitable substrate (glass, silicon, or any other support material). Next, the photosensitive film is exposed to white or ultraviolet light inducing a photochemical reaction in the photosensitive sol-gel glass network with the end photoproduct being a metal oxide. The photodeposited metal oxide is permanently bound to the sol-gel film glass network as a glass modifier during a heat treatment process, which in turn induces a permanent refractive index increase in the glass. The refractive index increase is dependent on the concentration of the photosensitizer and on the light energy used in the exposure process. Therefore, a spatially varying light intensity during exposure results in a spatially varying refractive index profile. This refractive index profile induced in the film can be designed to guide light.
  • [0006]
    Exposure of the photosensitive sol-gel film to white or ultraviolet light induces the unbinding of the metal from the photoliabile moiety component of the photosensitizer followed by the binding of the metal to the sol-gel film. The exposed regions of the sol-gel film are converted to a metal oxide silica film by first and second step heatings at a low temperature and high temperature, respectively. The low temperature drives out the unexposed (unbound) photosensitizer and the unbound photolabile moiety. The higher temperature step unbinds the organic component from the bound photosensitizer and drives it off. This step also permanently binds the metal to the silica film forming a metal oxide glass modifier. If the sol-gel film is deposited on a glass or silicon substrate, a metal oxide doped silica region of Si—O-M-O—Si is formed in the exposed regions acting as a glass modifier which in turn modifies the refractive index. The unexposed photosensitizer is driven off during the heat treatment steps. Since no material is removed from the sol-gel film in this process, as in the case of prior-art processes, the resulting top surface is planar, thus leading to a simpler process for producing devices and for achieving increased lifetime of resulting devices.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • [0007]
    FIGS. 1, 2, 4 and 5 are schematic side views of thin films in accordance with the principles of this invention; and FIG. 3 is a block diagram of the steps for fabricating a structured thin film in accordance with this invention.
  • DETAILED DESCRIPTION OF THE INVENTION
  • [0008]
    FIG. 1 is a side view of film 11 of a sol-gel film with R-M-X constituents dissolved therein. The film is shown formed (usually by a well known spinning technique) on the SiO2 surface layer 12 on a silicon substrate 13. The R constituents are taken from a class of volatile organic materials consisting of CH3, CH3—CH2, CH3—CH2—CH2, the M constituents (metals) are taken from the class of metals consisting of group IVB metals Ge, Sn and Pb, Group VIB including Se and Te, Group VIIIA including Fe, Co, Ni, and Group IVA including Ti and Zr and rare earth metals, and the X constituents (photolabile moiety) are taken from the class consisting of chlorine, iodine, fluorine, bromine, and carbonyls.
  • [0009]
    FIG. 2 shows an alternate embodiment where the sol-gel film 20 is formed on a glass substrate 21. FIGS. 1 and 2 represent the initial sol-gel solution formed on appropriate substrates of silicon (FIG. 1) and glass (FIG. 2). The process of forming the sol-gel solution into useful film structures is discussed in connection with FIG. 3.
  • [0010]
    Specifically, FIG. 3 is a block diagram of the process for fabricating structured films from the sol-gel solution of FIGS. 1 and 2. Block 31 of FIG. 3 represents the step of forming a sol-gel film with inclusions of R-M-X on a suitable substrate (as shown in FIG. 1 or FIG. 2). Block 32 represents the exposure of the film through a mask to light in a range of wavelengths from ultraviolet (UV) through the visible range. This step unbinds the photolabile moiety (X) and binds the metal (M) to the silicon oxide.
  • [0011]
    Block 33 of FIG. 3 represents the step of heating the film to about 300 degrees C. for a time to bind the metal permanently to the SiO2. This step also drives off the unexposed organometallic photosensitizer from the entire sol-gel layer and the unbound photolabile moiety (X) from the exposed portions of the sol-gel layer. Block 34 of FIG. 3 represents the final heating step to about 900 degrees C. for unbinding the organic component (R) from the bound photosensitizer and driving off that component. This step also permanently binds the metal to the silica sol-gel film forming a metal oxide glass modifier.
  • [0012]
    FIG. 4 shows the structure of FIG. 1 with a mask 40 in place. Mask 40 is opaque to the incident light (arrow 41) in regions 42 and 43 and is transparent to light in region 44. The result of exposure to light is a structured film (in excess of 1 micron) where the exposed region of the film includes Si—O-M-O—Si and the unexposed regions include SiO2.
  • [0013]
    The concentration of photodeposited metal oxide determines the index of refraction of the exposed region which can be made relatively high compared to that of adjacent regions. If we visualize region 44 extending away from the view as indicated by the broken lines in FIG. 5, the resulting structure can be seen to represent a waveguide with the “core” being buried as indicated.
  • [0014]
    In one specific embodiment, a sol-gel film 1-10 microns thick was formed on a silicon substrate 1 cm×0.5 cm×0.1 cm thick with a SiO2 surface layer<2 microns thick thereon. The sol-gel film included Sn (M) 2%, 1 (X) 2%, and (CH3)3 (R) 2%. Region 44 has a width of 10 microns, exposed to light with a wavelength of 254 nm for 30 minutes. The exposed region had an index of refraction of 1.55 and the unexposed regions had indices of refraction of 1.45. The film has a thickness of 1-10 microns after processing and has unchanged lateral dimensions.
  • [0015]
    In another embodiment, a sol-gel film 1-10 microns thick was formed on a glass substrate 1 cm×0.5 cm×0.1 cm thick. The sol-gel film included Ti (M) 2%, Cl (X) 4%, and Cp (R) 4% where Cp is cyclopentadienyl. Region 44 has a width of 10 microns, exposed to light with a wavelength of 514 nm for 120 minutes. The exposed region had an index of refraction of 1.75 and the unexposed region had indices of refraction of 1.45. The film had an final thickness of 1-10 microns with the lateral dimensions thereof being unchanged.

Claims (15)

  1. 1. A glass thin film derived from a thin film of photosensitive sol-gel doped with an organometallic photosensitizer, said organometallic photosensitizer having a formula R-M-X, where X is a photolabile moiety, M is a metal, and R is a volatile organic compound, wherein said thin film of photosensitive sol-gel has a thickness in excess of one micron.
  2. 2. A thin film as in claim 1, said film being formed on a substrate having a surface including silicon and oxygen.
  3. 3. A thin film as in claim 2 wherein said surface comprises SiO2 and is a silica enriched thin layer on a silicon substrate.
  4. 4. A thin film as in claim 1, said film being formed on a glass substrate.
  5. 5. A thin film as in claim 1, wherein R is taken from a class of low-volatile organic molecules consisting of CH3, CH3—CH2, CH3—CH2—CH2, and Cp, M is a metal taken from a class consisting of metals in Groups IVA, IVB, and VIB, transition metals and rare earth metals, and X is a photolabile moiety taken from a class consisting of halogens and carbonyls.
  6. 6. A thin film as in claim 3 where R comprises CH3, M comprises Sn, and X comprises I.
  7. 7. A thin film as in claim 3 wherein R comprises cyclopentadienyl.
  8. 8. A thin film as in claim 3 wherein M comprises Ti.
  9. 9. A thin film as in claim 3 wherein X comprises Cl.
  10. 10. A thin film as in claim 4 wherein R comprises CH3.
  11. 11. A thin film as in claim 4 wherein M comprises Pb.
  12. 12. A thin film as in claim 4 wherein X comprises Cl.
  13. 13. A thin film as in claim 2 including thereon a mask opaque to light in the UV and visible ranges.
  14. 14. A thin film of sol-gel derived glass on a silica substrate, said film including at least one metal oxide doped silica region of Si—O-M-O—Si with adjacent regions of SiO2, where M is a metal, said film having a thickness substantially in excess of one micron and being free of cracks and lateral shrinkage, and wherein said metal oxide is photodeposited from an organometallic photosensitizer included in the sol-gel used to form said film.
  15. 15. A method for forming a photosensitive sol-gel film including regions of different indices of refraction, said method comprising the steps of forming a photosensitive sol-gel film including an organometallic photosensitizer on a silica substrate, exposing said film through a mask to light of a wavelength and for a time for unbinding different amounts of metal constituents and of said sensitizer in different sections along at least a first channel thereof, exposing said film to heat at a first temperature and for a time to drive off the unbound sensitizer and to bind the metal constituents of said sol-gel film, and exposing said layer to heat at a second temperature higher than said first temperature for a time to unbind and drive off the organic constituents of said sol-gel film.
US11110372 2000-05-19 2005-04-19 Thin film sol-gel derived glass Abandoned US20060040109A1 (en)

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US09574841 US6881530B1 (en) 2000-05-19 2000-05-19 Thin film sol-gel derived glass
US11110372 US20060040109A1 (en) 2000-05-19 2005-04-19 Thin film sol-gel derived glass

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8507035B2 (en) 2011-05-26 2013-08-13 Advenira Enterprises, Inc. Method and apparatus for coating a complex object and composite comprising the coated object

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8668961B2 (en) * 2008-07-31 2014-03-11 Guardian Industries Corp. Titania coating and method of making same

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US4725110A (en) * 1984-08-13 1988-02-16 United Technologies Corporation Method for impressing gratings within fiber optics
US5080962A (en) * 1985-02-25 1992-01-14 University Of Florida Method for making silica optical devices and devices produced thereby
US5080503A (en) * 1989-12-12 1992-01-14 Ecole Polytechnique Optical waveguide device and method for making such device
US5151958A (en) * 1990-08-23 1992-09-29 Oy Nokia Ab Adaptor device for coupling together optical waveguides produced by k-na ion exchange with optical waveguides produced by ag-na ion exchange
US5265185A (en) * 1992-10-02 1993-11-23 The United States Of America As Represented By The Secretary Of The Army Optical waveguides in electro-optical polymers and method
US5360834A (en) * 1989-08-01 1994-11-01 Fraunhofer-Gesellschaft Zur Forderung Der Angewandten Forschung E.V. Process for photoinitiated control of inorganic network formation in the sol-gel process
US5574807A (en) * 1993-10-29 1996-11-12 Rutgers University Coupler used to fabricate add-drop devices, dispersion compensators, amplifiers, oscillators, superluminescent devices, and communications systems
US5585640A (en) * 1995-01-11 1996-12-17 Huston; Alan L. Glass matrix doped with activated luminescent nanocrystalline particles
US5620495A (en) * 1995-08-16 1997-04-15 Lucent Technologies Inc. Formation of gratings in polymer-coated optical fibers
US6054253A (en) * 1997-10-10 2000-04-25 Mcgill University-The Royal Institute For The Advancement Of Learning Solvent-assisted lithographic process using photosensitive sol-gel derived glass for depositing ridge waveguides on silicon
US6103363A (en) * 1995-09-15 2000-08-15 Saint-Gobain Recherche Substrate with a photocatalytic coating
US6115518A (en) * 1996-08-10 2000-09-05 Nortel Networks Corporation Optical waveguide Bragg reflection gratings
US6158245A (en) * 1997-07-29 2000-12-12 Physical Optics Corporation High efficiency monolithic glass light shaping diffuser and method of making
US6268089B1 (en) * 1998-02-23 2001-07-31 Agere Systems Guardian Corp. Photorecording medium and process for forming medium

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US6446467B1 (en) 1997-07-29 2002-09-10 Physical Optics Corporation Monolithic glass light shaping diffuser and method for its production
CA2218273A1 (en) 1997-10-10 1999-04-10 M. Amir Fardad Solvent-assisted lithographic process using photosensitive sol-gel derived glass for depositing ridge waveguides on silicon

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US4725110A (en) * 1984-08-13 1988-02-16 United Technologies Corporation Method for impressing gratings within fiber optics
US5080962A (en) * 1985-02-25 1992-01-14 University Of Florida Method for making silica optical devices and devices produced thereby
US5360834A (en) * 1989-08-01 1994-11-01 Fraunhofer-Gesellschaft Zur Forderung Der Angewandten Forschung E.V. Process for photoinitiated control of inorganic network formation in the sol-gel process
US5080503A (en) * 1989-12-12 1992-01-14 Ecole Polytechnique Optical waveguide device and method for making such device
US5151958A (en) * 1990-08-23 1992-09-29 Oy Nokia Ab Adaptor device for coupling together optical waveguides produced by k-na ion exchange with optical waveguides produced by ag-na ion exchange
US5265185A (en) * 1992-10-02 1993-11-23 The United States Of America As Represented By The Secretary Of The Army Optical waveguides in electro-optical polymers and method
US5574807A (en) * 1993-10-29 1996-11-12 Rutgers University Coupler used to fabricate add-drop devices, dispersion compensators, amplifiers, oscillators, superluminescent devices, and communications systems
US5585640A (en) * 1995-01-11 1996-12-17 Huston; Alan L. Glass matrix doped with activated luminescent nanocrystalline particles
US5620495A (en) * 1995-08-16 1997-04-15 Lucent Technologies Inc. Formation of gratings in polymer-coated optical fibers
US6103363A (en) * 1995-09-15 2000-08-15 Saint-Gobain Recherche Substrate with a photocatalytic coating
US6115518A (en) * 1996-08-10 2000-09-05 Nortel Networks Corporation Optical waveguide Bragg reflection gratings
US6158245A (en) * 1997-07-29 2000-12-12 Physical Optics Corporation High efficiency monolithic glass light shaping diffuser and method of making
US6054253A (en) * 1997-10-10 2000-04-25 Mcgill University-The Royal Institute For The Advancement Of Learning Solvent-assisted lithographic process using photosensitive sol-gel derived glass for depositing ridge waveguides on silicon
US6268089B1 (en) * 1998-02-23 2001-07-31 Agere Systems Guardian Corp. Photorecording medium and process for forming medium

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8507035B2 (en) 2011-05-26 2013-08-13 Advenira Enterprises, Inc. Method and apparatus for coating a complex object and composite comprising the coated object
US9044775B2 (en) 2011-05-26 2015-06-02 Advenira Enterprises, Inc. System and process for coating an object
US9050619B2 (en) 2011-05-26 2015-06-09 Advenira Enterprises, Inc. System and process for coating an object

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Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:OPTINETRICS, INC.;REEL/FRAME:017546/0185

Effective date: 20060424