Method of depositing layer

Abstract

A method for making a coated glass article, the method comprising providing a glass substrate having a surface, providing an aqueous solution of dimethyltin dichloride (DMT), evaporating the aqueous solution of dimethyltin dichloride to form a gaseous mixture comprising dimethyltin dichloride and water, and drying the gaseous mixture of dimethyltin dichloride and water. The method includes depositing a gaseous mixture on a surface of a glass substrate, delivering the gaseous mixture to the surface of the glass substrate, and depositing a tin oxide-based layer on the surface of the glass substrate wherein the surface of the glass substrate is at a temperature of at least 550 DEG C when the gaseous mixture is delivered to the surface of the glass substrate.

Description

[0001] The present invention relates to a method for depositing a layer on a substrate surface.

[0002] Coatings on substrate surfaces find use in many fields. Some of the more useful coatings are metal oxides, such as tin oxide. Some metal oxides, including doped tin oxide, can form transparent conductive oxide (TCO) coatings.

[0003] Methods for depositing metal oxide coatings include physical vapor deposition methods, such as sputtering, or liquid-based methods, such as sol-gel using spin coating or dip coating techniques, etc. One particularly useful method for depositing coatings is chemical vapor deposition (CVD), in which a fluid precursor in vapor form is delivered to the substrate surface where it reacts and / or decomposes, thereby depositing the coating. Different subsets of CVD include metal organic (MO) CVD, combustion (C) CVD, plasma enhanced (PE) CVD, and aerosol assisted (AA) CVD.

[0004] An important aspect of a successful CVD process is the choice of precursor. In the case of tin oxide coatings, many metal precursors have been studied. For more than thirty years, dimethyltin dichloride (DMT) has been widely used as a precursor for the deposition of tin oxide coatings. For example, in US5090985A, DMT is heated to a liquid, combined with nitrogen, evaporated, mixed with oxygen and water vapor, and directed onto the surface of a hot glass substrate as it is manufactured by a float glass process.

[0005] DMT is typically provided as a solid material which requires specialized containers, making transportation and storage difficult. It would be beneficial to provide greater versatility in how DMT is used as a precursor for tin oxide coatings, and therefore how it is transported and stored.

[0006] According to a first aspect of the present invention there is provided a method for producing a coated glass article,

[0007] The method comprises:

[0008] providing a glass substrate having a surface,

[0009] providing an aqueous solution of dimethyltin dichloride (DMT),

[0010] evaporating an aqueous solution of dimethyltin dichloride to form a gaseous mixture comprising dimethyltin dichloride and water,

[0011] delivering the gaseous mixture to the surface of the glass substrate, and

[0012] Depositing a tin oxide-based layer on the surface of a glass substrate,

[0013] Wherein the surface of the glass substrate is at a temperature of at least 550° C. when the gas mixture is delivered to the surface of the glass substrate.

[0014] Surprisingly, it has been found that an aqueous solution of DMT can be used directly for the deposition of tin oxide on glass substrates at the above temperatures. This provides a useful alternative to the conventional method of evaporating DMT and then combining it with water vapor.

[0015] In the context of the present invention, when a layer is referred to as being "based on" one or more specific materials, this means that the layer mainly consists of the respective one or more materials, which generally means that it contains at least about 50 atomic % of the one or more materials.

[0016] In the following discussion of the invention, unless stated to the contrary, the disclosure of alternative values ​​for the upper or lower limits of the permitted range of a parameter, together with an indication that one of the values ​​is more highly preferred than another, should be interpreted as implying such a statement: each intermediate value of the parameter between the more preferred and less preferred values ​​of the alternative value is itself preferred to the less preferred value, and is also preferred to every value between the less preferred value and the intermediate value.

[0017] Throughout the specification, the term "comprising" or "containing" means including the specified component(s) but not excluding the presence of other components. The term "consisting essentially of" or "consisting essentially of" means including the specified components but excluding other components, with the exception of materials present as impurities, unavoidable materials present as a result of the process for providing the components, and components added for purposes other than achieving the technical effects of the present invention. Typically, when referring to a composition, a composition consisting essentially of a set of components will contain less than 5% by weight, typically less than 3% by weight, and more typically less than 1% by weight of unspecified components.

[0018] The term "consisting of" or "composed of" means the inclusion of specified components but the exclusion of other components.

[0019] Whenever appropriate, use of the terms "comprising" or "containing" may also include the meaning of "consisting essentially of" or "consisting essentially of," and may also include the meaning of "consisting of" or "consisting of," depending on the context.

[0020] References herein such as "in the range of x to y" are meant to include an interpretation of "from x to y," thus including the values ​​x and y.

[0021] In the context of the present invention, a transparent material or a transparent substrate is a material or a substrate that is capable of transmitting visible light, so that an object or an image located outside or behind the material can be clearly seen through the material or substrate.

[0022] In the context of the present invention, for any given location on a layer surface, the "thickness" of a layer is represented by the distance through the layer in the direction of the layer's smallest dimension from that location on the layer surface to a location on the opposite surface of the layer.

[0023] In the context of the present invention, a "derivative" is a chemical substance that is structurally related to another chemical substance and can theoretically be derived from it.

[0024] When the gaseous mixture is delivered to the surface of the glass substrate, preferably, the surface of the glass substrate is at a temperature of at least 570° C., more preferably at least 580° C., even more preferably at least 590° C., most preferably at least 600° C., but preferably at most 800° C., more preferably at most 750° C., even more preferably at most 730° C., most preferably at most 720° C. In some preferred embodiments, when the gaseous mixture is delivered to the surface of the glass substrate, the surface of the glass substrate is at a temperature of at least 580° C. but at most 750° C. Depositing the layer when the substrate is at these preferred temperatures provides greater layer crystallinity, which can improve toughness (resistance to heat treatment).

[0025] Preferably, the coated glass article exhibits a sheet resistance of at most 50 ohms / square, more preferably at most 40 ohms / square, even more preferably at most 30 ohms / square, most preferably at most 25 ohms / square, but preferably at least 1 ohm / square, more preferably at least 3 ohms / square, even more preferably at least 5 ohms / square. In alternative embodiments, the coated glass article may exhibit a sheet resistance of 40 to 350 ohms / square, preferably 40 to 325 ohms / square, or the coated glass article may exhibit a sheet resistance of 1000 to 3000 ohms / square. The sheet resistance exhibited by the coated glass article is measured on the surface of the glass substrate on which the tin oxide-based layer is deposited. The sheet resistance exhibited by the coated glass article can be measured using a 4-point probe method and a commercially available 4-point probe.

[0026] Preferably, the gas mixture further comprises molecular oxygen and / or a carrier gas. More preferably, the gas mixture further comprises molecular oxygen and a carrier gas. Molecular oxygen can be provided as part of a gas composition such as air or in a substantially purified form. Preferably, the carrier gas comprises nitrogen, argon and / or helium. Regardless of the specific composition, since the gas mixture consists of more than one gas, it is preferred to premix the gases so that the gas mixture is substantially homogeneous prior to depositing the tin oxide-based layer.

[0027] Preferably, the aqueous solution of dimethyltin dichloride has a concentration of at least 30 wt%, more preferably at least 40 wt%, even more preferably at least 45 wt%, but preferably at most 70 wt%, more preferably at most 60 wt%, even more preferably at most 55 wt%.

[0028] Preferably, the gas mixture has a DMT mole percentage of at least 0.5 mol%, more preferably at least 1 mol%, even more preferably at least 1.5 mol%, but preferably at most 10 mol%, more preferably at most 7 mol%, even more preferably at most 5 mol%.

[0029] Preferably, the gas mixture has a molar percentage of water of at least 15 mol%, more preferably at least 25 mol%, even more preferably at least 30 mol%, but preferably at most 60 mol%, more preferably at most 50 mol%, even more preferably at most 40 mol%. In some preferred embodiments, the gas mixture comprises separately added water in addition to the water formed by evaporating the aqueous DMT solution.

[0030] Preferably, the gas mixture has a mole percentage of oxygen of at least 15 mol%, more preferably at least 25 mol%, even more preferably at least 30 mol%, but preferably at most 50 mol%, more preferably at most 40 mol%, even more preferably at most 35 mol%.

[0031] Preferably, the surface of the glass substrate is the main surface of the glass substrate. Preferably, the glass substrate is transparent. The glass substrate can be a transparent metal oxide-based glass plate. Preferably, the glass plate is a transparent float glass plate, preferably a low-iron float glass plate. Transparent float glass refers to a glass having a composition as defined in BS EN 572-1 and BS EN 572-2 (2004). For transparent float glass, the Fe2O3 weight content is generally 0.11%. Float glass with a Fe2O3 content of less than about 0.05% by weight is generally referred to as low-iron float glass. This glass generally has the same basic composition as the other component oxides, i.e., low-iron float glass is also a soda-lime silicate glass, such as transparent float glass. Typically, low-iron float glass has less than 0.02% by weight of Fe2O3. Alternatively, the glass plate is a borosilicate-based glass plate, an alkali-aluminosilicate-based glass plate, or an alumina-based crystalline glass plate.

[0032] Preferably, the formation of the gaseous mixture comprises heating an aqueous solution of dimethyltin dichloride and / or any other precursor compound. Preferably, the heating uses a bubbler system or a thin film evaporator system. A thin film evaporator system is particularly suitable for production scale processes.

[0033] Preferably, the aqueous solution of dimethyltin dichloride is heated to a temperature of at least 160°C, more preferably at least 170°C, even more preferably at least 175°C, but preferably at most 240°C, more preferably at most 220°C, even more preferably at most 210°C.

[0034] Preferably, the gas mixture reaches a vapour pressure of at least 0.01 bar, more preferably at least 0.03 bar, even more preferably at least 0.04 bar, most preferably at least 0.05 bar.

[0035] Preferably, the method is implemented using chemical vapor deposition (CVD). CVD can be implemented together with the manufacture of a substrate, preferably a transparent glass substrate. In one embodiment, the glass substrate can be formed using a known float glass manufacturing process. Preferably, the method is carried out during the float glass manufacturing process. In this embodiment, the glass substrate may also be referred to as a glass ribbon. Conveniently, CVD can be carried out in a metal bath, in an annealing furnace, or in an annealing furnace gap. A preferred CVD method is atmospheric pressure CVD (e.g., online CVD carried out in a float glass process). However, it should be understood that the CVD process can be used separately from the float glass manufacturing process, or well used after the glass ribbon is formed and cut.

[0036] As mentioned above, preferably in the float glass production process, CVD can be implemented at substantially atmospheric pressure. Alternatively, low pressure CVD or ultra-high vacuum CVD can be used to implement CVD. CVD can be implemented using aerosol-assisted CVD or direct liquid injection CVD. In addition, CVD can be implemented using microwave plasma-assisted CVD, plasma-enhanced CVD, remote plasma-enhanced CVD, atomic layer CVD, combustion CVD (flame pyrolysis), hot wire CVD, metal organic CVD, rapid thermal CVD, vapor phase epitaxy or light-induced CVD. Usually after depositing any (one or more) CVD layers, the glass substrate is cut into sheets for storage or convenient transportation.

[0037] In certain embodiments, CVD is a dynamic deposition process. Therefore, in these embodiments, when a tin oxide-based layer is formed thereon or above, the glass substrate is mobile. Preferably, when a tin oxide-based layer is deposited, the glass substrate moves at a predetermined rate of, for example, greater than 1.78 m / min (70 in / min), more preferably greater than 2.5 m / min (98.4 in / min). In one embodiment, when a tin oxide-based layer is deposited, the glass substrate moves at a rate between 3.175 m / min (125 in / min) and 16.7 m / min (657 in / min), preferably between 3.175 m / min (125 in / min) and 15.24 m / min (600 in / min).

[0038] In the case where the process is implemented during a float glass manufacturing process, a float glass apparatus can be provided, which preferably includes a runner section along which molten glass is transported from a melting furnace to a metal bath section where a continuous glass ribbon is formed by the process. The glass ribbon can proceed from the bath section through an adjacent annealing furnace and a cooling section. The continuous glass ribbon can be used as a substrate on which a tin oxide-based layer is deposited.

[0039] The trough portion may include a bottom, a top, opposing side walls and end walls, and the molten tin liquid is contained in the bottom. It should be understood that the trough may include other suitable materials to achieve the desired result. The top, side walls and end walls together may define a shell cavity in which a non-oxidizing atmosphere is maintained to prevent oxidation of the molten tin. In addition, a coating device including a gas distribution beam may be located in the trough portion. The gas distribution beam in the trough portion may be used to apply a tin oxide-based layer by the method of the subject matter currently described, or to apply an additional coating to the substrate before or after applying a tin oxide-based layer.

[0040] In operation, the molten glass can flow along the flow channel below the regulating gate and flow downwardly onto the surface of the tin liquid in a controlled amount. On the tin liquid, the molten glass expands laterally under the influence of gravity and surface tension and certain mechanical influences, and it advances through the liquid tank to form a band. The band can be removed over the lifting rollers and preferably subsequently conveyed through the annealing furnace and the cooling section on the alignment rollers. A heater can be provided in the annealing furnace for gradually reducing the temperature of the glass ribbon as it is conveyed through according to a predetermined manner. In addition, ambient air can usually be directed to the glass ribbon by a fan in the cooling section.

[0041] The method of the presently described subject matter can be implemented in a metal bath section or further along the production line. For example, a tin oxide based layer can be deposited in the gap between a metal bath section and an annealing furnace or in the annealing furnace itself.

[0042] In order to implement the method in the metal bath part, a suitable non-oxidizing atmosphere can be maintained, typically nitrogen or a nitrogen and hydrogen mixture in which nitrogen is dominant, to prevent oxidation of the molten tin. Atmosphere gas can enter through a pipeline operably connected to a distribution manifold. Non-oxidizing atmosphere gas can be introduced at a rate sufficient to compensate for normal losses and maintain a slightly positive pressure (about 0.001 to about 0.01 atmosphere higher than the ambient atmospheric pressure) to prevent penetration of the external atmosphere. For the purpose of the subject matter currently described, the above-mentioned pressure range is considered to constitute normal atmospheric pressure. The heat for maintaining the desired temperature range in the tin bath and the shell cavity can be provided by the radiant heater in the shell cavity and the glass ribbon itself.

[0043] The atmosphere in the annealing furnace is usually atmospheric air. However, if necessary, an inert atmosphere can be maintained in the annealing furnace portion. Similarly, the atmosphere in the gap between the annealing furnace and the liquid tank is usually atmospheric air and the liquid tank portion atmosphere, but an inert atmosphere can be provided. In either case, the pressure of the inert atmosphere can be substantially similar to the pressure of the liquid tank atmosphere.

[0044] The gas distribution beam may be located in the liquid tank section, in the gap between the liquid tank section and the annealing furnace, or in the annealing furnace to deposit the tin oxide based layer on the glass ribbon substrate.The gas distribution beam is a form of reactor that can be used to practice the method of the present subject matter.

[0045] According to the presently described subject matter, a distribution beam suitable for supplying precursor material is constructed as an inverted, generally channel-shaped frame formed by spaced inner and outer walls and defining two closed cavities. A suitable heat exchange medium may be circulated through the closed cavities to maintain the distribution beam at a desired temperature.

[0046] Preferably, the gas mixture is delivered to the coating equipment. In certain embodiments, before the deposition of the layer based on tin oxide, the gaseous mixture is fed through the coating equipment and discharged from the coating equipment using one or more gas distribution beams. Preferably, the gaseous mixture is formed before the coating equipment is fed. For example, the aqueous solution of dimethyltin dichloride can be evaporated and delivered to the feed line connected to the inlet of the coating equipment. Molecular oxygen and / or carrier gas such as nitrogen can be delivered to the feed line and mixed with DMT and water. In other embodiments, the gas mixture can be formed in the coating equipment.

[0047] The gas mixture may be supplied through a supply conduit. Depending on the location of deposition, the supply conduit may be surrounded by a cooling fluid. The supply conduit may extend along the distribution beam and allow the gas mixture to enter through downcomers spaced apart along the supply conduit. The supply conduit may lead to a delivery chamber within a header carried by a frame. The gaseous mixture introduced through the downcomers may be discharged from the delivery chamber through a passage toward a coating chamber that defines a vapor space leading to the glass substrate, where the gaseous mixture flows along the surface of the substrate.

[0048] Baffles may be provided within the delivery chamber to equalize the flow of the gas mixture through the distribution beam, thereby ensuring a smooth, laminar, uniform flow of the gas mixture through the distribution beam toward the glass substrate. Spent precursor gas may be collected and removed by exhaust chambers along the sides of the distribution beam.

[0049] Various forms of distributor beams for chemical vapor deposition are suitable for the present method and are known in the prior art. In one such alternative distributor beam configuration, the gaseous mixture is introduced through a gas supply tube where it is cooled by a cooling fluid circulated through a multi-tube. The gas supply tube may lead to a glass restrictor through an elongated hole.

[0050] The gas restrictor may include a plurality of metal strips that are longitudinally curled in a wavy pattern and mounted vertically in abutting relation to one another, extending along the length of the distributor. Adjacent curled metal strips may be arranged "out of phase" to define a plurality of vertical channels therebetween. The cross-sectional area of ​​these vertical channels may be less than the cross-sectional area of ​​the gas supply tube, so that the gas mixture is released from the gas restrictor at a substantially constant pressure along the length of the distributor.

[0051] The gas mixture can be released from the gas restrictor to the inlet side of a generally U-shaped guide channel, which generally includes an inlet branch leading to the coating chamber of the glass substrate and at least one exhaust branch, thereby extracting the spent precursor gas from the glass. It should be understood that the guide channel can have any suitable size, shape and configuration as desired. The rounded corners of the blocks defining the coating channel promote uniform laminar flow of the coating parallel to the surface of the glass substrate.

[0052] Preferably, the tin oxide based layer is deposited on the surface of the glass substrate at a deposition rate of at least 2 nm / sec, more preferably at least 5 nm / sec, even more preferably at least 7 nm / sec.

[0053] Preferably, the tin oxide based layer comprises tin(IV) oxide, more preferably consists essentially of tin(IV) oxide, even more preferably consists of tin(IV) oxide.

[0054] In some preferred embodiments, the tin oxide-based layer may comprise doped tin oxide and / or may comprise a mixed oxide. The doped tin oxide may be doped with one or more of fluorine, indium, antimony, boron, manganese, zinc, aluminum, chromium, phosphorus, strontium or cadmium. Preferably, the doped tin oxide is doped with one or more of fluorine, indium or antimony. More preferably, the doped tin oxide is doped with fluorine. In this case, preferably, the gas mixture also comprises HF and / or trifluoroacetic acid. Doping the tin oxide-based layer may make the layer conductive.

[0055] When doped, preferably the tin oxide-based layer contains at least 0.2 atomic % of dopant, more preferably at least 0.4 atomic % of dopant, even more preferably at least 0.6 atomic % of dopant, most preferably at least 0.8 atomic % of dopant, but preferably at most 5 atomic % of dopant, more preferably at most 2 atomic % of dopant, even more preferably at most 1.5 atomic % of dopant, most preferably at most 1.2 atomic % of dopant. These preferred ranges can provide advantages in optimizing cell efficiency for solar cell applications.

[0056] The tin oxide-based layer can be deposited directly on the surface of the glass substrate. Alternatively, the tin oxide-based layer can be deposited indirectly on the surface of the glass substrate, i.e., the tin oxide-based layer can be deposited on top of one or more previously deposited layers. For example, the tin oxide-based layer can be deposited on top of the silicon dioxide-based layer, and preferably in direct contact with it. In some preferred embodiments, the tin oxide-based layer is deposited on top of and in direct contact with the silicon dioxide-based layer, wherein the silicon dioxide-based layer has been deposited on top of and in direct contact with another tin oxide-based layer.

[0057] In the case where the process is implemented during the float glass manufacturing process, preferably, the surface of the glass substrate is the gas side surface. Coated glass manufacturers generally prefer to deposit the coating on the gas side surface (opposite to the tin side surface of the float glass) because deposition on the gas side surface can improve the properties of the coating.

[0058] In addition, the coated glass article can exhibit low haze values. As discussed herein, the term "haze" refers to the percentage of incident visible light that is scattered when passing through the coated glass article. In addition, as described herein, the haze exhibited by the coated glass article is measured from the surface of the glass substrate on which the tin oxide-based layer has been deposited. In one embodiment, the coated glass article can exhibit a haze of 0.5% or less. Preferably, the coated glass article exhibits a haze of 0.4% or less. In some embodiments, the coated glass article exhibits a haze of 0.1-0.4%. The haze exhibited by the coated glass article can be measured using a commercially available haze meter such as BYK-Gardner Haze-gard plus.

[0059] Any invention described herein may be combined mutatis mutandis with any features of any other invention described herein.

[0060] It should be understood that the optional features applicable to one aspect of the present invention may be used in any combination and in any quantity. In addition, they may also be used in any combination and in any quantity with any other aspect of the present invention. This includes, but is not limited to, a dependent claim from any claim being used as a dependent claim of any other claim in the claims of this application.

[0061] The reader is invited to pay attention to all papers and documents filed concurrently or before the specification related to this application, and which are disclosed to the public together with this specification, and the contents of all these papers and documents are incorporated herein by reference.

[0062] All features disclosed in this specification (including any accompanying claims, abstract and drawings) and / or all steps of any method or process so disclosed may be combined in any combination, except combinations in which at least some of such features and / or steps are mutually exclusive.

[0063] Unless expressly stated otherwise, each feature disclosed in this specification (including any attached claims, abstracts and drawings) may be replaced by alternative features for the same, equivalent or similar purpose. Therefore, unless expressly stated otherwise, each feature disclosed is only an example of a series of general equivalent or similar features.

[0064] The present invention will now be further described by the following specific embodiments, which are given by way of illustration and not limitation, with reference to the accompanying drawings, in which:

[0065] Figure 1 is a schematic cross-sectional view of a coated glass article according to certain embodiments of the present invention;

[0066] Figure 2 is a schematic cross-sectional view of a coated glass article according to certain embodiments of the present invention;

[0067] Figure 3 is a schematic vertical cross-sectional view of an apparatus for implementing a float glass process according to certain embodiments of the present invention, the apparatus combining several CVD apparatuses for manufacturing coated glass articles.

[0068] Figure 1 A cross section of a coated glass article 1 according to certain embodiments of the present invention is shown. The coated glass article 1 comprises a transparent float glass substrate 2 which has been coated with a tin oxide based layer 3 using CVD.

[0069] Figure 2A cross section of a coated glass article 1 according to certain embodiments of the present invention is shown. The coated glass article 1 comprises a transparent float glass substrate 2 which has been coated sequentially with a silicon dioxide based layer 4 and a tin oxide based layer 3 using CVD.

[0070] As described above, the method of the present invention can be implemented using CVD in conjunction with the manufacture of a glass substrate in a float glass process. The float glass process is typically implemented using a float glass apparatus, such as Figure 3 The apparatus 10 is shown. However, it should be understood that the float glass apparatus 10 described herein is merely an example of such an apparatus.

[0071] like Figure 3 As shown, the float glass apparatus 10 may include a flow channel portion 20 along which molten glass 19 is transported from a melting furnace to a metal bath portion 11 where a glass substrate is formed. In this embodiment, the glass substrate will be referred to as a glass ribbon 8. However, it should be understood that the glass substrate is not limited to a glass ribbon. The glass ribbon 8 advances from the bath portion 11 through an adjacent annealing furnace 12 and a cooling portion 13. The metal bath portion 11 includes: a bottom 14, a top 16, opposing side walls (not shown) and an end wall 17, in which a molten tin liquid 15 is contained. The top 16, the side walls and the end wall 17 together define a shell cavity 18 in which a non-oxidizing atmosphere is maintained to prevent oxidation of the molten tin 15.

[0072] In operation, molten glass 19 flows along flow channel 20 below regulating gate 21 and flows down onto the surface of molten tin 15 in controlled amounts. On the molten tin surface, molten glass 19 spreads laterally under the influence of gravity and surface tension and certain mechanical influences, and it advances through molten tin 15 to form glass ribbon 8. Glass ribbon 8 is removed from trough section 11 on lifting rollers 22 and thereafter conveyed on aligned rollers through annealing furnace 12 and cooling section 13. Deposition of the coating is preferably performed in the metal trough section 11, although deposition can be performed further along the glass production line, such as in gap 28 between metal trough 11 and annealing furnace 12, or in annealing furnace 12.

[0073] like Figure 3 As shown, four CVD devices 9, 9A, 9B, 9C are shown in the metal bath portion 11. Therefore, depending on the frequency and thickness of the required coating, some or all of the CVD devices 9, 9A, 9B, 9C may need to be used. One or more additional coating devices (not shown) may be provided. One or more CVD devices may be alternatively or supplementarily arranged in the annealing furnace gap 28. Any by-products are removed by the coating machine extraction slot and then by the pollution control device. For example, in one embodiment, a silicon dioxide layer is formed using CVD device 9A, and a fluorine-doped tin oxide layer is formed using CVD device 9.

[0074] A suitable non-oxidizing atmosphere, typically nitrogen or a mixture of nitrogen and hydrogen with nitrogen being predominant, may be maintained in the metal bath portion 11 to prevent oxidation of the molten tin 15 constituting the metal bath. The atmospheric gas enters through a conduit 23 operatively connected to a distribution manifold 24. The non-oxidizing gas is introduced at a rate sufficient to compensate for normal losses and maintain a slightly positive pressure, about 0.001 to about 0.01 atmospheres higher than the ambient atmospheric pressure, so as to prevent penetration of the external atmosphere. For the purpose of describing the present invention, the above pressure range is considered to constitute normal atmospheric pressure.

[0075] CVD is typically performed at substantially atmospheric pressure. Thus, the pressure in the metal bath portion 11, the annealing furnace 12, and / or the gap 28 between the metal bath 11 and the annealing furnace 12 may be substantially atmospheric pressure. Heat for maintaining the desired temperature range in the metal bath portion 11 and the shell 18 is provided by a radiant heater 25 within the shell 18. The atmosphere within the annealing furnace 12 is typically atmospheric air, since the cooling portion 13 is not enclosed and the glass ribbon 8 is therefore open to the ambient atmosphere. The glass ribbon 8 is then cooled to ambient temperature. To cool the glass ribbon 8, ambient air is directed toward the glass ribbon 8 in the cooling portion 13 by a fan 26. A heater (not shown) may also be provided in the annealing furnace 12 to gradually reduce the temperature of the glass ribbon 8 as it is conveyed through it in a predetermined manner. Example

[0076] Chemical components included aqueous DMT (50 wt% / wt, Galata), nitrogen (compressed liquid, Air Products), and oxygen (PT# or ED300, ultra dry, AirGas) and were used as received without further purification.

[0077] Aqueous DMT was used directly as a precursor to perform atmospheric pressure chemical vapor deposition of SnO thin films on SiO coated low iron soda lime float glass sheets (2.8 mm×20.3 cm×61.0 cm, “substrates”) using an in-line micro dynamic coater. The substrate was mounted on an electronically controlled ceramic conveyor “boat” that moved through the coating furnace section. First, the substrate was paused in the preheating section until it reached 620°C and then moved into the main furnace maintained at the same temperature. Once in the main furnace, the substrate was either moved at a line speed of 190.5 cm / min (preferably 63.5-889 cm / min, more preferably 190.5-508 cm / min) or was stationary for 15 or 20 seconds while the gas mixture left the 15.2 cm precursor nozzle to deposit a dynamic or static coating, respectively. For the examples herein, dynamic coatings were prepared. From the main furnace, the coated glass article was moved to the annealing section where it was held until it was reduced to the set temperature (400°C) and then removed from the furnace for fan cooling.

[0078] Prepare gaseous mixture as follows: nitrogen carrier gas is piped into a stainless steel (316 steel) pressure tank for holding and conveying aqueous dimethyl tin dichloride. Using a sapphire rotor flowmeter, aqueous dimethyl tin dichloride is metered into a tubular evaporator set at 350 ° F (176.7 ° C). Make additional nitrogen flow through the barrel of the evaporator to carry dimethyl tin dichloride and water vapor to the coating head via heated pipelines (200-220 ° C) and 4-way connectors (in 200 ° C baking ovens). Mix oxygen with DMT, water and nitrogen just before the 4-way connector. After each deposition, use the water from the metering pressure tank to purge the system.

[0079] Use five kinds of different conditions to prepare embodiment, as shown in table 1 below, so that the ratio of DMT and water in gaseous mixture changes. Prepare each embodiment at three different times, and measure the average measured value of thickness and efficiency. Table 1 shows the ratio of each component in the gaseous mixture, and nitrogen constitutes the surplus. Table 1 also shows the flow rate of each component, the average thickness of the deposited tin oxide layer and the average deposition efficiency. Deposition efficiency is basically the percentage of DMT mole number in the gaseous mixture that tin oxide is actually deposited on the substrate per minute. The area coated is limited by the width of the glass and its linear velocity.

[0080]

[0081] Table 1 - Deposition conditions and resulting coating thickness and deposition efficiency according to several embodiments of the present invention

[0082] The results shown in Table 1 show that the thickness of the tin oxide layer increases with increasing ratios of DMT and water in the gas mixture. Furthermore, all examples demonstrate reasonable deposition efficiency.

[0083] The invention is not limited to the details of the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification (including any attached claims, abstract and drawings), or to any novel step or any novel step combination of steps of any method or process disclosed in this manner.

Claims

1. A method for producing a coated glass article, the method comprising: providing a glass substrate having a surface, providing an aqueous solution of dimethyltin dichloride (DMT), evaporating an aqueous solution of dimethyltin dichloride to form a gaseous mixture comprising dimethyltin dichloride and water, delivering the gaseous mixture to the surface of the glass substrate, and Depositing a tin oxide-based layer on the surface of a glass substrate, Wherein when delivering the gas mixture to the surface of the glass substrate, the surface of the glass substrate is at a temperature of at least 550°C.

2. The method of claim 1, wherein when the gaseous mixture is delivered to the surface of the glass substrate, the surface of the glass substrate is at a temperature of at least 570°C, preferably at least 580°C, more preferably at least 590°C, most preferably at least 600°C, but preferably at most 800°C, more preferably at most 750°C, even more preferably at most 730°C, most preferably at most 720°C.

3. The method of claim 1 or 2, wherein the surface of the glass substrate is at a temperature of at least 580°C but at most 750°C when the gas mixture is delivered to the surface of the glass substrate.

4. The method according to any of the preceding claims, wherein the coated glass article exhibits a sheet resistance of at most 50 ohms / square, preferably at most 40 ohms / square, more preferably at most 30 ohms / square, most preferably at most 25 ohms / square, but preferably at least 1 ohm / square, more preferably at least 3 ohms / square, even more preferably at least 5 ohms / square.

5. The method according to any one of the preceding claims, wherein the gas mixture further comprises molecular oxygen and / or a carrier gas.

6. The process according to any one of the preceding claims, wherein the aqueous solution of dimethyltin dichloride has a concentration of at least 30 wt.-%, preferably at least 40 wt.-%, more preferably at least 45 wt.-%, but preferably at most 70 wt.-%, more preferably at most 60 wt.-%, even more preferably at most 55 wt.-%.

7. The process according to any one of the preceding claims, wherein the gas mixture has a molar percentage of DMT of at least 0.5 mol%, preferably at least 1 mol%, more preferably at least 1.5 mol%, but preferably at most 10 mol%, more preferably at most 7 mol%, even more preferably at most 5 mol%.

8. The process according to any one of the preceding claims, wherein the gas mixture has a molar percentage of water of at least 15 mol%, preferably at least 25 mol%, more preferably at least 30 mol%, but preferably at most 60 mol%, more preferably at most 50 mol%, even more preferably at most 40 mol%.

9. The process according to any one of the preceding claims, wherein the gas mixture has a molar percentage of oxygen of at least 15 mol%, preferably at least 25 mol%, more preferably at least 30 mol%, but preferably at most 50 mol%, more preferably at most 40 mol%, even more preferably at most 35 mol%.

10. The method according to any one of the preceding claims, wherein the formation of the gas mixture comprises heating an aqueous solution of dimethyltin dichloride and / or any other precursor compound, preferably wherein the heating uses a bubbler system or a thin film evaporator system.

11. The process according to claim 10, wherein the aqueous solution of dimethyltin dichloride is heated to a temperature of at least 160°C, preferably at least 170°C, more preferably at least 175°C, but preferably at most 240°C, more preferably at most 220°C, even more preferably at most 210°C.

12. The method according to any one of the preceding claims, wherein the method is performed using chemical vapour deposition (CVD).

13. The method according to any one of the preceding claims, wherein the method is carried out during a float glass manufacturing process. 14 . The method according to claim 1 , wherein the layer based on tin oxide comprises doped tin oxide and / or comprises a mixed oxide.

15. A method according to claim 14, wherein the doped tin oxide is doped with one or more of fluorine, indium, antimony, boron, manganese, zinc, aluminium, chromium, phosphorus, strontium or cadmium, preferably fluorine.

16. The method according to any of the preceding claims, wherein the tin oxide based layer is deposited directly on the surface of the glass substrate.

17. The method according to any one of claims 1 to 15, wherein the tin oxide based layer is deposited indirectly on the surface of the glass substrate, and wherein the tin oxide based layer is deposited above a silicon dioxide based layer and preferably in contact therewith.

18. Method according to claim 17, wherein the silicon dioxide based layer has been deposited over and in direct contact with a further tin oxide based layer.

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