Classifications

• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL 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
  • C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL 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
  • C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
  • C03C17/006—Surface treatment of glass, not in the form of fibres or filaments, by coating with materials of composite character
  • C03C17/007—Surface treatment of glass, not in the form of fibres or filaments, by coating with materials of composite character containing a dispersed phase, e.g. particles, fibres or flakes, in a continuous phase
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL 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
  • C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
  • C03C17/006—Surface treatment of glass, not in the form of fibres or filaments, by coating with materials of composite character
  • C03C17/008—Surface treatment of glass, not in the form of fibres or filaments, by coating with materials of composite character comprising a mixture of materials covered by two or more of the groups C03C17/02, C03C17/06, C03C17/22 and C03C17/28
  • C03C17/009—Mixtures of organic and inorganic materials, e.g. ormosils and ormocers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL 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
  • C03C2217/00—Coatings on glass
  • C03C2217/40—Coatings comprising at least one inhomogeneous layer
  • C03C2217/425—Coatings comprising at least one inhomogeneous layer consisting of a porous layer
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL 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
  • C03C2218/00—Methods for coating glass
  • C03C2218/10—Deposition methods
  • C03C2218/11—Deposition methods from solutions or suspensions
  • C03C2218/113—Deposition methods from solutions or suspensions by sol-gel processes

Definitions

• the present invention relates to a substrate with at least one thick layer of inorganic gel, glass, glass ceramic or ceramic material, a method for producing substrates with at least one layer of inorganic gel, glass, glass ceramic or ceramic material and their use, e.g. in optics, optoelectronics or electronics.
• Si0 2 layers and doped SiO 2 layers with a layer thickness in the ⁇ m range are suitable for different applications in the field of optics and optoelectronics.
• SiO 2 layers with layer thicknesses in the ⁇ m range are used as dielectric insulation layers on silicon for semiconductor production. Another focus is the production of sufficiently thick buffer layers on silicon for the production of integrated optical components.
• SiO 2 layers doped with different ions are used in the production of passive and active planar optical waveguides.
• Thick SiO 2 layers in the ⁇ m range are generally produced using thermal oxidation or flame hydrolysis. Both methods are very costly and time-consuming. A 10-15 ⁇ m thick SiO 2 layer is required for buffer layers for the production of planar waveguides. For the production of materials with dopings for matching the refractive index, such as Pb, P, Al, or dopings for the production of active materials such as He, the problem arises that flame hydrolysis cannot achieve sufficiently high doping concentrations.
• the sol-gel process represents an alternative to the production of thick SiO 2 layers and doped SiO 2 layers.
• the sol-gel process can be used to easily incorporate suitable ions for the production of reinforcing materials.
• Tetraethoxysilane (TEOS) in ethanol which has been hydrolyzed with aqueous hydrochloric acid or water, is frequently used as the starting material for sol-gel SiO 2 layers on silicon wafers and on glass substrates. It was only possible to achieve maximum layer thicknesses of 400 nm or coarse porous layers were obtained which are unusable for optical applications because of their porosity.
• wave-guiding layers are based on inorganic sol-gel materials, with the problem of the low layer thickness arising in all cases.
• SiO 2 -Ti0 2 layers are discussed as wave-guiding materials.
• Other doping materials for SiO 2 layers besides Ti0 2 are P 2 O 5 and GeO 2 .
• the invention was therefore based on the object of developing a method for producing gel, glass or ceramic layers, in particular of SiO 2 layers and doped SiO 2 layers, on substrates, by means of which thick layers can be obtained with a coating process, which are crack-free and are particularly suitable for optical or optoelectronic applications.
• this could be achieved by a process for producing substrates with at least one layer of inorganic gel, glass, glass ceramic or ceramic material, in which a coating composition comprising nanoscale particles and water-soluble organic flexibilizers is applied to the substrate and heat-treated.
• This is apparently due to the agglomerate-free arrangement of the nanoscale particles in the gel layer.
• the highly porous layers are transparent, which means that the pores contained therein are predominantly or essentially nanopores. Obviously, these nanopores enable crack-free sintering at Tg.
• the process according to the invention now makes it possible to produce crack-free thick layers with a thickness of up to several micrometers, which can be sintered to form dense layers by means of thermal compression.
• the diffusion paths to be covered during sintering are small, so that crack-free compaction is achieved.
• the layers remain transparent in every stage from the gel to the glass, so that there is the possibility of adjusting the refractive index and / or the dielectric constant via the compression temperature.
• Layers with thicknesses in the ⁇ m range or gel body have always been white.
• the large pores contained in the prior art layers not only contribute to the scattering of light, but also lead to the formation of cracks when compacted. In contrast to this, they enable the process according to the invention available nanoporous layers the formation of transparent and crack-free layers at every stage.
• any temperature-stable substrate can be used as the substrate.
• metal substrates can also be used, but this is not preferred.
• semi-metals and in particular semiconductors are suitable substrates.
• Preferred substrates are glass substrates such as float glass, borosilicate glass, lead crystal or silica glass, glass ceramic substrates, semiconductor substrates such as optionally doped Si or Ge, or ceramic substrates such as Al 2 O 3 , ZrO 2 or SiO 2 mixed oxides.
• Glass and semiconductor substrates, in particular substrates made of silicon or silicon dioxide are particularly preferred.
• the silicon can be doped, for example with P, As, Sb and / or B.
• the silicon dioxide can also be doped. Examples of doping are given below in the description of the nanoscale particles. It can be, for example, silicon wafers or silicon coated with silicon dioxide, as are used in the semiconductor industry and optoelectronics.
• the substrate must be selected so that it survives the necessary thermal treatment.
• the substrate may have been pretreated, e.g. by structuring or by in particular partial coating, e.g. about printing techniques. Therefore, e.g. there are optical and / or electrical microstructures, e.g. Optical fibers or conductor tracks.
• the coating composition is, in particular, a coating sol which contains a flexibilizer in the form of a water-soluble organic polymer and / or oligomer and nanoscale particles.
• the nanoscale particles are in particular nanoscale inorganic particles.
• the particle size is, for example, in the range from below 100 nm. In particular, the particle sizes are in the range from 1 nm to 40 nm, preferably 5 nm to 20 nm, particularly preferably 8 nm to 12 nm.
• the size specifications relate to average particle diameters. This material can be used in the form of a powder, but is preferably used in the form of a sol.
• nanoscale particles examples include oxides or oxide hydrates of Si, Al, B, Zn, Cd, Ti, Zr, Ce, Sn, Sb, In, La, Fe, Cu, Ta, Nb, V, Mo or W, for example, if appropriate hydrated oxides, such as ZnO, CdO, SiO 2 , TiO 2 , ZrO 2 , CeO 2 , SnO 2 , Sb 2 O 3 , AIOOH, Al 2 O 3 , ln 2 O 3) La 2 O 3 , Fe 2 O 3 , Cu 2 O, Ta 2 O 5 , Nb 2 O 5 , V 2 O 5 , MoO 3 or WO 3 , phosphates, silicates, zirconates, aluminates, stannates and corresponding mixed oxides (for example those with a perovskite structure such as BaTiO 3 and PbTiO 3 ).
• nanoscale particles are SiO 2 , CeO 2 , Al 2 O 3 , AIOOH, TiO 2 , ZrO 2 , SnO 2 , Sb 2 O 3 and ZnO.
• SiO 2 is very particularly preferably used as a nanoscale particle.
• the nanoscale particles can be produced by the known methods.
• SiO 2 particles can be produced, for example, via base-catalyzed hydrolysis and condensation of silicon alcoholates or via other known processes for the production of silica sols, for example via the water glass route. Pyrogenic or thermal production processes are also known. Such SiO 2 particles are commercially available, for example as silica sols. Analogous processes are also known for other oxide particles.
• Aqueous sols of the nanoscale particles are preferably used, for example aqueous silica sols and in particular colloidal, electrostatically stabilized aqueous silica sols.
• dopants can be used. All glass or ceramic-forming elements are generally suitable as dopants.
• glass or ceramic-forming components (in their oxide form) for doping are B 2 O 3 , Al 2 O 3 , P 2 O 5 , GeO 2 , Bi 2 O 3 or oxides of gallium, tin, arsenic, antimony, lead, Niobium and tantalum, network converters, such as alkali and alkaline earth oxides, components which increase the refractive index, such as, for example, PbO, TiO 2 , ZrO 2 , HfO 2 , Ta 2 O 5 , Tl 2 0, optically active components, such as rare earth oxides, for example Er 2 O 3 , Yb 2 O 3 , Nd 2 O 3 , Sm 2 O 3 , Ce 2 O 3 , Eu 2 O 3 , subgroup elements, for example La 2 O 3 , Y 2 0 3 , WO 3> and ln 2 O 3 , S
• the doping is e.g. in concentrations between 0% and 15 mol%, preferably 0% and 10 mol% and particularly preferably 0% and 7.5 mol%, measured on the total oxide content.
• the doping is e.g. by adding the doping components as water-soluble salts, as alkoxides or as soluble complexes, e.g. Acetylacetonates, acid complexes or amine complexes, to the coating sol and optionally hydrolysis.
• the nanoscale particles used such as the silica sols
• the flexibilizer for example a PVA binder
• the nanodispersive state of the (SiO 2 ) xerogel framework is important in order to achieve a homogeneous element distribution in a short time.
• Another advantage is that due to the real nanoporosity, complete densification is achieved at Tg.
• Water-soluble organic flexibilizers are also used in the coating composition. These are in particular water-soluble organic polymers and / or oligomers. Water-soluble organic polymers are preferably used, for. B. water-soluble organic binder. They are, for example, polymers and / or oligomers which have polar groups, such as hydroxyl, primary, secondary or tertiary amino, carboxyl or carboxylate groups.
• Typical examples are polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, polyvinyl pyridine, polyallylamine, polyacrylic acid, polyvinyl acetate, polymethyl methacrylic acid, starch, gum arabic, other polymeric alcohols, such as, for example, polyethylene-polyvinyl alcohol copolymers, polyethylene glycol, polypropylene glycol and poly (4-vinylphenol).
• a preferred flexibilizer is polyvinyl alcohol, for example the commercially available Mowiol® 18-88 from Hoechst. Polyvinyl alcohols, for example with an MW of 1200, can also be used.
• the flexibilizers can be used individually or as a mixture of two or more of them.
• the flexibilizers In contrast to the solvent, the flexibilizers cannot be distilled off at elevated temperatures either, but are burned out by the heat treatment, i.e. they cannot be vaporized (non-destructively). In particular, they are substances that are solid at room temperature.
• the coating composition in particular also contains one or more solvents as the third component.
• suitable solvents known to the person skilled in the art can be used.
• suitable solvents are water, alcohols, preferably lower aliphatic alcohols, for example C 1 -C 4 -alcohols, such as methanol, ethanol, 1-propanol, i-propanol and 1-butanol, ketones, preferably lower dialkyl ketones, for example C r C 4 Dialkyl ketones, such as acetone and methyl isobutyl ketone, ethers, preferably lower dialkyl ethers, for example C 1 -C 4 dialkyl ethers, such as dioxane and THF, amides, such as dimethylformamide, and acetonitrile.
• the solvents can be used alone or in their mixtures.
• Particularly preferred solvents are water, alcohol-water mixtures with alcohol contents between 0% and 90% by volume, mixtures of water and tetrahydrofuran (THF) with THF contents between 0% and 90% by volume, other single-phase mixtures of water and organic solvents such as dioxane, acetone or acetonitrile, a minimum water content of 10% by volume being preferred.
• Particularly preferred solvents contain at least 10% by volume of water.
• the water content in the solvent is particularly preferably> 50%, in particular> 90%.
• Aqueous coating compositions, ie with a minimum water content, are therefore preferably used.
• the proportion of solvent in the coating composition largely depends on the coating method chosen. It is e.g. for spray coatings e.g. about 95%, for spin or dip coatings e.g. about 80%, for doctor blade coatings e.g. about 50% and for printing pastes e.g. about 30%.
• the coating composition can in principle contain further additives, e.g. Fluorosilane condensates, e.g. are described in EP 587667.
• the flexibilizer is processed with the nanoscale particles (and the solvents specified above) to form a coating sol such that this flexibilizer takes over the steric stabilization of the SiO 2 nanoparticles when the corresponding sol-gel layers dry. As a result, no agglomerates or aggregates are formed when the layers dry, which lead to large pores.
• the volume ratio between the flexibilizer and the nanoscale particles is selected so that the flexibilizer approximately fills the gaps between the solvent-free particles.
• the share of the flexibilizer is preferably selected so that it largely fills the spaces between the nanoparticles after evaporation of the solvent, ie the volume ratio of nanoparticles to flexibilizer is preferably 72:28 to 50:50, particularly preferably 70:30 to 60:40 and in particular 68: 32 to 62:38, e.g. about 65:35.
• the layer production can be carried out with all common wet processes.
• the coating composition is applied to the substrate via conventional coating methods, e.g. Dipping, flooding, drawing, pouring, spinning, spraying, spraying, brushing, knife coating, rolling or conventional printing techniques, e.g. with printing pastes.
• Electrophoretic coating processes are less or not suitable at all because of the disadvantages listed above.
• the coating composition applied to the substrate is dried, the flexibilizing agent is burned out and, if appropriate, the coating is then partially or completely compacted.
• the drying can also be partially or completely before the heat treatment, e.g. by simply venting.
• the solvent is also suitably removed by the heat treatment.
• heat treatment conventional methods, such as. B. heating in the oven or the so-called "Rapid Thermal Annealing" (flash annealer, flame treatment) can be used, the latter especially for compression.
• radiant heaters such as IR radiators or lasers
• the heat treatment is carried out for example under an oxygen-containing or inert atmosphere, for example nitrogen, or air, but other components, such as ammonia, chlorine or carbon tetrachloride, can also be used as the atmosphere, alone or as an additional component.
• temperatures of up to approx. 450 ° C. are used, for example by tempering in an oven.
• the compression temperatures depend on the desired degree of residual porosity and on the composition. They are generally in the range from 450 ° C. to 1200 ° C. for glass layers and in the range from 500 ° C. to 2000 ° C. for ceramic layers. Temperature programs are preferably used for the heat treatment, the parameters, such as heating rates, holding temperatures and temperature ranges, being regulated. These are known to the person skilled in the art.
• a gel still containing the flexibilizing agent is obtained, e.g. in the case of higher-boiling solvents, it can also be removed in parallel.
• This inorganic gel or xerogel can be converted into a glass, glass ceramic or ceramic-like layer by partial or complete compaction. The layers remain transparent at every stage from the gel to the glass. This also gives the possibility of setting the refractive index and / or the dielectric constant via the compression temperature.
• even crack-free thick layers for example with a thickness of more than 1 ⁇ m, in particular more than 3 ⁇ m or 5 ⁇ m or even more than 8 ⁇ m, can be obtained, which are moreover transparent and therefore suitable for optical applications.
• the gel layers after removal of the solvent but not the flexibilizer have, for example, layer thicknesses from 0.5 ⁇ m to 200 ⁇ m, preferably 5 ⁇ m to 50 ⁇ m and particularly preferably from 10 ⁇ m to 20 ⁇ m.
• the inorganic layers obtained in the process according to the invention can also be structured, in particular microstructured.
• the structuring or microstructuring can be carried out in particular for the production of optical or electronic structures. It can take place in the gel layer or in the compressed, partially compressed or non-compressed inorganic layers.
• the structuring is preferably carried out in the gel state, in particular after removal of the solvent but before removal of the flexibilizing agent.
• methods known from the prior art e.g. photolithography, embossing or etching and masking methods, are used.
• Microstructuring before thermal compression allows the production of particularly thick (8 ⁇ m to 20 ⁇ m) compacted microstructures.
• the coated substrates produced are particularly suitable as optical, optoelectronic, electronic, micromechanical or dirt-repellent components.
• Typical application examples are passive and active optical waveguides, buffer and cladding layers for passive and active optical waveguides on glass, ceramic and Si substrates, dielectric layers and microstructures on glass, ceramic and silicon substrates for the production of semiconductor components, silicate and alkali silicate layers and microstructures for the thermal and anodic bonding of silicon substrates, optical components, for example gratings and light-scattering structures, microlenses, microcylinder lenses, microfresnel lenses or arrays made of these, microreactors or transparent dirt-repellent microstructures.
• silica sols Two different silica sols were used to synthesize the SiO 2 sols.
• a silica sol was synthesized beforehand from TEOS with ammonia in ethanol, the process being designed so that after the synthesis the SiO 2 pond size was 10 nm and the solids content was adjusted to 5.58% by weight (name of this silica sol: KS10 ).
• the second silica sol used is commercially available (Levasil VPAc 4039, Bayer). To prepare the sol, 75 g of KS10 and 23.25 g of VPAc 4039 are combined and 39.06 g of a 10% strength by weight aqueous solution of the organic binder PVA (Mowiol 18-88, Hoechst) are added to this solution.
• the desired solids content (25% by weight, based on the oxide content of the sol) is achieved by removing solvent by distillation on a rotary evaporator. After concentrating the sol, the pH is adjusted to pH 9-9.5, in which 0.4 g of a 25% NH 3 solution are added dropwise. Before the coating process, the brine is filtered through syringe filters (1.2 ⁇ m).
• the distillative removal is then carried out of the solvent on a rotary evaporator until a solids content of 10% by weight (based on the oxide content) has been set in.
• the sol is filtered through syringe filters to 1.2 ⁇ m.
• KS10 100 g of KS10 are slowly added dropwise to 6.5 g of 1 molar aqueous HNO 3 with stirring. Then 40 g of acetate-stabilized, particulate CeO 2 sol (CeO 2 ACT, 20% by weight, from AKZO-PQ) are slowly added at room temperature with stirring. Then 37.7 g of the organic flexibilizer PVA-18-88 are added as a 10% strength by weight solution in water. Before coating, this sol is filtered through a syringe filter to 1.2 ⁇ m.
• sols synthesized as stated above are applied to various substrates, preferably SiO 2 and silicon, using the customary coating methods (for example spinning, spraying, dipping or knife coating).
• the layers are compressed in the muffle furnace in accordance with a specified temperature program.
• the layers are heated from room temperature to 250 ° C at a heating rate of 0.8 K / min, the temperature is kept at 250 ° C for 1 hour. From 250 ° C is heated at a heating rate of 0.8 K / min to 450 ° C and again held at this temperature for 1 h.
• the final compression temperature for the undoped SiO 2 layers is 1100 ° C, which is held for 1 hour.
• Final compression temperatures of 500 to 1000 ° C lead to porous layers with a correspondingly lower refractive index.
• the heating rate for compression from 450 to 1100 ° C is 2 K / min.
• the doped layers are compacted at the same heating rate up to 1000 ° C for 1 h.

Landscapes

• Chemical & Material Sciences (AREA)
• General Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Geochemistry & Mineralogy (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Composite Materials (AREA)
• Inorganic Chemistry (AREA)
• Dispersion Chemistry (AREA)
• Surface Treatment Of Glass (AREA)
• Glass Melting And Manufacturing (AREA)
• Laminated Bodies (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=7638847

Family Applications (1)

Country Status (8)

Cited By (1)

Families Citing this family (28)

Family Cites Families (20)

• 2000
  • 2000-04-14 DE DE10018697A patent/DE10018697A1/de not_active Withdrawn
• 2001
  • 2001-04-12 AU AU2001258332A patent/AU2001258332A1/en not_active Abandoned
  • 2001-04-12 WO PCT/EP2001/004215 patent/WO2001079127A1/de active Application Filing
  • 2001-04-12 CA CA002405942A patent/CA2405942A1/en not_active Abandoned
  • 2001-04-12 EP EP01931595A patent/EP1272437A1/de not_active Withdrawn
  • 2001-04-12 JP JP2001576393A patent/JP2003531087A/ja active Pending
  • 2001-04-12 KR KR1020027013694A patent/KR20020093905A/ko not_active Application Discontinuation
  • 2001-04-12 US US10/240,878 patent/US20030059540A1/en not_active Abandoned

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events