# Patent

## Title
Coated article having low-E coating with ion beam treated IR reflecting layer and corresponding method

## Abstract

A coated article is provided that may be used as a vehicle windshield, insulating glass (IG) window unit, or the like. An ion beam is used to treat an infrared (IR) reflecting layer(s) of such a coated article. Advantageously, this has been found to improve sheet resistance (Rs) properties, emittance, solar control properties, and/or durability of the coated article.

## Background
This application is a divisional of application Ser. No. 10/893,532, filed Jul. 19, 2004 now U.S. Pat. No. 7,311,975 , which is a continuation-in-part (CIP) of U.S. patent application Ser. No. 10/875,515, filed Jun. 25, 2004 now U.S. Pat. No. 7,229,533 , the entire contents of which are hereby incorporated herein by reference in this application.


This invention relates to a coated article including a solar control coating such as a low-emissivity (low-E) coating. In certain example embodiments, the low-E coating includes an infrared (IR) reflecting layer(s) of a material such as silver (Ag) or the like which is ion beam treated. In certain example embodiments, the ion beam treatment is performed in a manner so as to cause the IR reflecting layer to realize compressive stress (as opposed to normal tensile stress), and/or to reduce electrical resistance (sheet resistance Rs and/or bulk resistance) and/or emissivity value(s) of the coated article. Coated articles according to certain example embodiments of this invention may be used in the context of vehicle windshields, insulating glass (IG) window units, other types of windows, or in any other suitable application.
BACKGROUND OF THE INVENTION
Coated articles are known in the art for use in window applications such as insulating glass (IG) window units, vehicle windows, and/or the like. Example non-limiting low-emissivity (low-E) coatings are illustrated and/or described in U.S. Pat. Document Nos. 6,723,211; 6,576,349; 6,447,891; 6,461,731; 3,682,528; 5,514,476; 5,425,861; and 2003/0150711, the disclosures of which are all hereby incorporated herein by reference.
In certain situations, designers of coated articles with low-E coatings often strive for a combination of high visible transmission, substantially neutral color, low emissivity (or emittance), low sheet resistance (Rs), and good durability. High visible transmission for example may permit coated articles to be more desirable in applications such as vehicle windshields or the like, whereas low-emissivity (low-E) and low sheet resistance (Rs) characteristics permit such coated articles to block significant amounts of IR radiation so as to reduce for example undesirable heating of vehicle or building interiors. It is often difficult to obtain high visible transmission and adequate solar control properties such as good IR blockage, combined with good durability (chemical and/or mechanical durability) because materials used to improve durability often cause undesirable drops in visible transmission and/or undesirable color shifts of the product upon heat treatment.
Low-E coatings typically include one or more IR reflecting layers. An IR reflecting layer is typically metallic or mostly metallic, and is often of a material such as silver (Ag), gold (Au), or the like. The silver or gold may be doped with other materials in certain instances. The purpose of the IR reflecting layer(s) is to block significant amounts of IR radiation, thereby preventing the same from undesirably heating up vehicle and/or building interiors which the coated article is protecting.
Generally speaking, the lower the electrical resistance (sheet resistance Rs and /or bulk resistance) of an IR reflecting layer, the better the IR reflecting characteristics thereof. However, it has heretofore been difficult to reduce resistance properties (and thus improve IR reflecting characteristics) of an IR reflecting layer without adversely affecting optical characteristics of a coated article (e.g., visible transmission, color, etc.) and/or durability of a coated article. For instances, significant changes in the thickness of an IR reflecting layer alone may affect resistance, but at the same time may adversely affect durability and/or optical characteristics of the coating.
In view of the above, it will be apparent to those skilled in the art that there exists a need in the art for a technique for reducing resistance characteristics of an IR reflecting layer(s) thereby improving IR reflecting characteristics thereof and thus solar control properties of a coated article, without significantly adversely affecting durability and/or optical characteristics of the coated article. There also exists a need in the art for a method of making such a coated article.
BRIEF SUMMARY OF EXAMPLE EMBODIMENTS OF THE INVENTION
In certain example embodiments of this invention, an infrared (IR) reflecting layer(s) is ion beam treated using at least ions from an inert gas such as argon (Ar) and/or Krypton (Kr). It has surprisingly been found that if the ion treatment is performed in a suitable manner, this causes (a) the electrical resistance of the IR reflecting layer to decrease compared to if the ion beam treatment was not performed, thereby improving IR reflecting characteristics thereof, (b) the emittance (e.g., normal) of the IR reflecting layer or coating to decrease compared to if the ion beam treatment was not performed, and/or (c) durability of the coated article to improve.
In certain example embodiments of this invention, it has unexpectedly been found that ion beam treatment of an IR reflecting layer of a material such as Ag, Au or the like, causes the stress of the layer to change from tensile to compressive. In this regard, it has been found that the compressive nature of the stress of the IR reflecting layer(s) can function to improve durability (chemical and/or mechanical) of the coated article.
Accordingly, suitable ion beam treating of an IR reflecting layer(s) has been found in certain example embodiments of this invention to achieve a combination of: (i) improved resistance of the IR reflecting layer, (ii) improved emittance, (iii) improved solar control characteristics of the coated article such as IR blocking, and/or (iii) improved durability of the coated article.
In certain example embodiments of this invention, the ion beam treating may be performed in a manner known as “peening.” In other words, the ion beam treatment of the IR reflecting layer may be performed after the IR reflecting layer has been originally sputter-deposited. After sputter-deposition of the IR reflecting layer in such instances, an ion beam comprising or consisting essentially of inert gas ions (e.g., Kr and/or Ar) is directed at the IR reflecting layer so as to impinge upon the same for ion beam treatment purposes. It has been found that this is advantageous for one or more of the reasons discussed above.
In other example embodiments of this invention, an IR reflecting layer may be formed in the following manner. First, a seed layer (e.g., of Ag or the like) is formed by sputtering. Then, after sputtering of the seed layer, ion beam assisted deposition (IBAD) is used to form an additional or remainder portion of the IR reflecting layer. In the IBAD type of ion beam treatment, both an ion beam source(s) and a sputtering target(s) are used. An ion beam from the ion beam source (e.g., including Ar+ ions) intersects with the material sputtered from the sputtering target(s) proximate the surface where the additional or remainder portion of the IR reflecting layer is being grown, so that the additional or remainder portion of the IR reflecting layer is grown/formed by a simultaneous combination of both the ion beam and sputtering.
In other example embodiments of this invention, the IR reflecting layer may be formed entirely using IBAD. At the beginning of the IR reflecting layer formation using IBAD, the volts applied to the ion source are low or zero so that the ion beam either is not formed or is of a low power type (i.e., low eV per ion). Then, during formation of the IR reflecting layer after at least some of the layer has been deposited, the voltage at the ion source is increased so as to increase the eV per ion in the ion beam. In other words, the ion energy is increased, either progressively or in a step-like manner, during formation of the IR reflecting layer. This prevents or reduces damages to the lower portion of the layer and/or to the layer under the same.
In certain example embodiments of this invention, there is provided a method of making a coated article, the method comprising: providing a glass substrate; forming at least one dielectric layer on the substrate; forming an infrared (IR) reflecting layer on the substrate over at least the first dielectric layer, where said forming of the IR reflecting layer comprises ion beam treating the IR reflecting layer; and forming at least one additional dielectric layer on the substrate over at least the IR reflecting layer.
In other example embodiments, there is provided a coated article including a glass substrates supporting a coating, wherein the coating comprises: at least one dielectric layer; an IR reflecting layer comprising Ag and/or Au provided on the substrate; at least one additional layer provided on the substrate over at least the IR reflecting layer; and wherein the IR reflecting layer comprises silver and has compressive stress and/or which is graded with respect to argon and/or krypton content.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flowchart illustrating certain steps carried out in making a coated article according to an example embodiment of this invention.
FIGS. 2(a) to 2(c) are cross sectional views illustrating various stages in manufacturing a coated article according to an example embodiment of this invention.
FIG. 3 is a cross sectional view of a coated article according to an example embodiment of this invention.
FIG. 4 is a cross sectional view of an example ion source that may be used to ion beam treat layers according to example embodiments of this invention.
FIG. 5 is a perspective view of the ion source of FIG. 4.
FIG. 6 is a diagram illustrating ion beam assisted deposition (IBAD) of a layer according to an example embodiment of this invention; this may be used to ion beam treat any layer mentioned herein that can be ion beam treated.
FIG. 7 is a flowchart illustrating certain steps carried out in making a coated article according to another example embodiment of this invention.
FIG. 8 is a flowchart illustrating certain steps carried out in accordance with another example embodiment of this invention.
FIG. 9 is a cross sectional view of a coated article according to another example embodiment of this invention (which may be made according to the process of FIG. 8 for example).



DETAILED DESCRIPTION OF EXAMPLES OF THE INVENTION
Referring now to the accompanying drawings in which like reference numerals indicate like parts throughout the several views.
Coated articles herein may be used in applications such as vehicle windshields, monolithic windows, IG window units, and/or any other suitable application that includes single or multiple glass substrates with at least one solar control coating thereon. In vehicle windshield applications, for example, a pair of glass substrates may be laminated together with a polymer based layer of a material such as PVB, and the solar control coating (e.g., low emissivity or low-E coating) is provided on the interior surface of one of the glass substrates adjacent the polymer based layer. In certain example embodiments of this invention, the solar control coating (e.g., low-E coating) includes either a single-silver stack or a double-silver stack, although this invention is not so limited in all instances (e.g., single silver stacks and other layer stacks may also be used in accordance with certain embodiments of this invention).
In certain example embodiments of this invention, an infrared (IR) reflecting layer(s) (e.g., see Ag inclusive layer 9 and/or 19 discussed below) is ion beam treated using at least ions from an inert gas such as argon and/or krypton. It has surprisingly been found that if the ion treatment is performed in a suitable manner, this causes (a) the electrical resistance of the IR reflecting layer(s) to decrease compared to if the ion beam treatment was not performed, thereby improving IR reflecting characteristics thereof, (b) emittance (e.g., normal type of emittance) of the layer to decrease compared to if the ion beam treatment was not performed, and/or (c) durability of the coated article to improve.
Moreover, in certain example embodiments of this invention, it has unexpectedly been found that ion beam treatment of an IR reflecting layer (e.g., 9 and/or 19) of a material such as Ag, Au or the like causes the stress of the layer to change from tensile to compressive. IR reflecting layers deposited by only sputtering typically have tensile stress. However, the use of ion beam treatment in a suitable manner has surprisingly been found to cause the stress of an IR reflecting layer(s) to be compressive. In this regard, it has been found that the compressive nature of the stress of the IR reflecting layer(s) can function to improve durability (chemical and/or mechanical) of the coated article. Moreover, it has also been found that such ion beam treatment also reduces electrical resistance and/or emittance of the coated article (i.e., of the IR reflecting layer(s) in particular) thereby improving solar control properties thereof.
Accordingly, suitable ion beam treating of an IR reflecting layer(s) has been found in certain example embodiments of this invention to achieve a remarkable combination of: (i) improved resistance and/or emittance of the IR reflecting layer, (ii) improved solar control characteristics of the coated article such as IR blocking, and (iii) improved durability of the coated article. With respect to durability, an example is that the coating is less likely to quickly corrode when exposed to environmental conditions such as high temperatures, high humidity, and so forth.
In certain example embodiments of this invention, a technique knows as IBAD may be used in ion beam treating an IR reflecting layer(s) (e.g., see FIGS. 1-7). However, in other example embodiments of this invention a technique referred to as “peening” may be used to ion beam treat an IR reflecting layer(s) (e.g., see FIGS. 4-5 and 8-9). In peening embodiments, the ion beam treatment is performed after the IR reflecting layer has been originally deposited by sputter-deposition or the like. In certain IBAD embodiments, sputtering and ion beam treatment may take place at the same time for layer formation and/or treatment. In certain example, instances, IBAD and peening embodiments may be combined.
Referring to FIGS. 1-3, in certain example embodiments of this invention, an IR reflecting layer (9 and/or 19) may be formed in the following manner. At least one underlying layer is formed on glass substrate 1 via sputtering or the like as shown in FIG. 2(a) (see step S1 in FIG. 1). In FIG. 3, the underlying layers would be layers 3 and 7. Then, a seed layer (e.g., of Ag or the like) is formed on the substrate over the underlying layer(s) by sputtering at least one target of Ag or the like as shown in FIG. 2(b) (see S2 in FIG. 1). The seed layer is typically metallic, or substantially metallic, and of a material such as Ag, Au or the like. However, in certain embodiments, the seed layer may consist essentially of Ag and/or Au, and be doped with small amounts of other materials such as oxygen or metal(s). Preferably, the seed layer is substantially of the same material (e.g., Ag) as the ultimate IR reflecting layer (9 and/or 19) being formed. Since the seed layer is formed sputtering, the seed layer will typically be formed in a manner so as to have tensile stress. In certain example embodiments of this invention, the Ag seed layer is sputtered onto the substrate so as to have a thickness of from about 10 to 100 Å, more preferably from about 30 to 80 Å, even more preferably from about 40 to 70 Å, with an example thickness being about 60 Å.
Then, after sputtering of the seed layer on the substrate as shown in FIG. 2(b), ion beam assisted deposition (IBAD) is used to form an additional or remainder portion of the IR reflecting layer (9 and/or 19) as shown in FIG. 2(c) (see S3 in FIG. 1). FIGS. 2(c) and 6 illustrate that in the IBAD type of ion beam treatment/formation, both an ion beam source(s) 26 and a sputtering device including a sputtering target(s) 50 are used. An ion beam B from the ion beam source 26 intersects with the material M sputtered from the sputtering target(s) 50 proximate the surface where the additional or remainder portion of the IR reflecting layer is being grown, so that the additional or remainder portion of the IR reflecting layer is grown/formed by a simultaneous combination of both the ion beam and sputtering. In certain example embodiments of this invention, a first Ag sputtering target is used for sputter-depositing the seed layer, and a second Ag sputtering target spaced apart from the first target is used to deposit/form the additional or remainder portion of the IR reflecting layer via IBAD.
The use of the seed layer and then the subsequent formation of the additional or remaining portion of the IR reflecting layer (9 and/or 19) using IBAD as shown in FIGS. 1-2 and 6 results in an IR reflecting layer that is graded with respect to argon content. In particular, an upper portion of the IR reflecting layer includes a higher Ar concentration than does a lower portion of the IR reflecting layer. This is because Ar ions do not impinge upon the layer during formation thereof until after the seed layer has been formed. Accordingly, the upper portion of the resulting IR reflecting layer includes a higher Ar content than does the lower portion of the layer. This grading would be for content of another element (e.g., Kr and/or Xe) if the other element(s) was used instead of or in place of Ar in the ion beam in alternative embodiments of this invention. In certain example embodiments, the upper portion of the IR reflecting layer (9 and/or 19) has an argon (or other inert element) concentration at least 10% higher than that of the lower portion of the IR reflecting layer, more preferably at least 20% higher, and most preferably at least 30% higher. The “lower portion” is merely some arbitrarily selected portion of the layer at least partially below the center point of the layer, where the “upper portion” of the layer is some arbitrarily selected portion of the layer at least partially above the center of the layer. In certain example instances, the upper portion may be the upper 20 Å of the IR reflecting layer, and the lower portion may be the lower 60 Å (or 20 Å) of the layer.
Thus, the resulting IR reflecting layer (9 and/or 19) shown in FIGS. 2(c) and 3 is made up of the combination of the Ag inclusive seed layer and the Ag inclusive layer formed immediately thereover via IBAD. Note that the seed layer will have been modified by the IBAD process, with Ar ions having been injected thereinto and/or its stress having been changed from tensile to compressive. As explained above, it has surprisingly been found that: (a) the IBAD formation of the Ag layer portion of the seed layer in a suitable manner causes the stress of the seed layer to change from tensile to compressive in the final IR reflecting layer 9 and/or 19; and (b) the IBAD formation of the additional Ag inclusive layer portion immediately over and contacting the seed layer results in an IR reflecting layer having improved electrical resistance properties and thus improved solar control functionality.
Then, following formation of the IR reflecting layer 9 and/or 19, additional layer(s) are deposited on the substrate 1 over at least the IR reflecting layer (see step S4 in FIG. 1). These additional layer in the example FIG. 3 embodiment may be layers 11-25 and/or 21-25.
In certain example embodiments, the resulting IR reflecting layer 9 and/or 19 has a thickness of from about 60 to 200 Å, more preferably from about 80 to 170 Å, even more preferably from about 100 to 140 Å, with an example being about 120 Å. Moreover, in certain example embodiments of this invention, the IR reflecting layer(s) 9 and/or 19 are substantially free of oxygen. For example, the IR reflecting layer(s) 9 and/or 19 include from about 0-10% oxygen, more preferably from about 0-5% oxygen, even more preferably from about 0-2% oxygen and most preferably from 0-1% oxygen. This substantially free of oxygen characteristic may be achieved throughout the entire thickness of the layer, or alternative in at least a central portion of the layer no located immediately adjacent the contact layers.
In certain example embodiments of this invention, the ion beam includes at least ions from an inert gas used in the ion source 26. For example, the ion beam B may be of or include Ar+ ions if only Ar gas is used in the ion source 26. In certain example embodiments of this invention, the ion beam is substantially free of oxygen ions and the gas used in the ion source 26 is substantially free of oxygen. Thus, the ion beam B and gas introduced into the ion source 26 include from 0-10% oxygen, more preferably from 0-5% oxygen, even more preferably from 0-2% oxygen, and most preferably from 0-1% oxygen (0% oxygen may be preferred in many instances). The ion beam is also substantially free of nitrogen ions in certain example embodiments of this invention.
Moreover, in certain example embodiments of this invention, in forming the additional or remainder portion of the IR reflecting layer(s) 9 and/or 19 via IBAD, an ion energy of from about 150 to 700 eV per Ar+ ion, more preferably of from about 200 to 600 eV per Ar+ ion, and most preferably about 500 eV per Ar+ ion is used. As an example, when only Ar gas is used in the ion source 26, an anode/cathode voltage of from about 300 to 1,400 V may be used at the source 26, more preferably from about 400 to 1,200 V, and most preferably about 1,000 V.
FIG. 3 is a side cross sectional view of a coated article according to an example non-limiting embodiment of this invention. The coated article includes substrate 1 (e.g., clear, green, bronze, or blue-green glass substrate from about 1.0 to 10.0 mm thick, more preferably from about 1.0 mm to 3.5 mm thick), and a low-E coating (or layer system) 2 provided on the substrate 1 either directly or indirectly. The coating (or layer system) 2 includes, in this example embodiment: dielectric silicon nitride layer 3 (which may be ion beam treated) which may be of Si3N4 or of any other suitable stoichiometry of silicon nitride in different embodiments of this invention, first lower contact layer 7 (which contacts IR reflecting layer 9), first conductive and preferably metallic or substantially metallic infrared (IR) reflecting layer 9, first upper contact layer 11 (which contacts layer 9), dielectric layer 13 (which may be deposited in one or multiple steps in different embodiments of this invention), another silicon nitride layer 14, second lower contact layer 17 (which contacts IR reflecting layer 19), second conductive and preferably metallic IR reflecting layer 19, second upper contact layer 21 (which contacts layer 19), dielectric layer 23, and finally dielectric silicon nitride overcoat layer 25 (which may be ion beam treated). The “contact” layers 7, 11, 17 and 21 each contact at least one IR reflecting layer. The aforesaid layers 3-25 make up low-E (i.e., low emissivity) coating 2 which is provided on glass or plastic substrate 1. Silicon nitride layer 25 is the outermost layer of the coating 2.
In embodiments herein discussing ion beam treatment of IR reflecting layer, the ion beam treatment/formation may be performed with respect to Ag layers 9 and/or 19.
In monolithic instances, the coated article includes only one glass substrate 1 as illustrated in FIG. 3. However, monolithic coated articles herein may be used in devices such as laminated vehicle windshields, IG window units, and the like. A laminated vehicle window such as a windshield includes first and second glass substrates laminated to one another via a polymer based interlayer (e.g., see U.S. Pat. No. 6,686,050, the disclosure of which is incorporated herein by reference). One of these substrates of the laminate may support coating 2 on an interior surface thereof in certain example embodiments. As for IG window units, an IG window unit may include two spaced apart substrates 1. An example IG window unit is illustrated and described, for example, in U.S. Pat. No. 6,632,491, the disclosure of which is hereby incorporated herein by reference. An example IG window unit may include, for example, the coated glass substrate 1 shown in FIG. 3 coupled to another glass substrate via spacer(s), sealant(s) or the like with a gap being defined therebetween. This gap between the substrates in IG unit embodiments may in certain instances be filled with a gas such as argon (Ar). An example IG unit may comprise a pair of spaced apart clear glass substrates each about 4 mm thick one of which is coated with a coating herein in certain example instances, where the gap between the substrates may be from about 5 to 30 mm, more preferably from about 10 to 20 mm, and most preferably about 16 mm. In certain example instances, the coating 2 may be provided on the interior surface of either substrate facing the gap.
Example details relating to layers 3, 7, 9, 11, 13, 14, 17, 19, 21, 23 and 25 of the FIG. 3 coating are discussed in U.S. patent application Ser. No. 10/800,012, the disclosure of which is hereby incorporated herein by reference. For example, dielectric layers 3 and 14 may be of or include silicon nitride in certain embodiments of this invention. Silicon nitride layers 3 and 14 may, among other things, improve heat-treatability of the coated articles, e.g., such as thermal tempering or the like. The silicon nitride of layers 3 and/or 14 may be of the stoichiometric type (Si3N4) type, nitrogen doped type due to ion beam treatment thereof as discussed herein, or alternatively of the Si-rich type in different embodiments of this invention. Any and/or all of the silicon nitride layers discussed herein may be doped with other materials such as stainless steel or aluminum in certain example embodiments of this invention. For example, any and/or all silicon nitride layers discussed herein may optionally include from about 0-15% aluminum, more preferably from about 1 to 10% aluminum, most preferably from 1-4% aluminum, in certain example embodiments of this invention. The silicon nitride may be deposited by sputtering a target of Si or SiAl in certain embodiments of this invention. Moreover, silicon nitride layer 3 may be ion beam treated in any manner discussed herein (e.g., with at least nitrogen ions via IBAD) in order to reduce sodium migration from the glass substrate toward the IR reflecting layer(s) during HT.
Infrared (IR) reflecting layers 9 and 19 are preferably substantially or entirely metallic and/or conductive, and may comprise or consist essentially of silver (Ag), gold, or any other suitable IR reflecting material. One or both of IR reflecting layers 9 and/or 19 may be formed by the ion beam inclusive techniques as discussed herein with respect to FIGS. 1-2. IR reflecting layers 9 and 19 help allow the coating to have low-E and/or good solar control characteristics. The IR reflecting layers may, however, be slightly oxidized in certain embodiments of this invention.
Dielectric layer 13 may be of or include tin oxide in certain example embodiments of this invention. However, as with other layers herein, other materials may be used in different instances. Lower contact layers 7 and/or 17 in certain embodiments of this invention are of or include zinc oxide (e.g., ZnO). The zinc oxide of layer(s) 7, 17 may contain other materials as well such as Al (e.g., to form ZnAlOx). For example, in certain example embodiments of this invention, one or more of zinc oxide layers 7, 17 may be doped with from about 1 to 10% Al, more preferably from about 1 to 5% Al, and most preferably about 2 to 4% Al. The use of zinc oxide 7, 17 under the silver 9, 19 allows for an excellent quality of silver to be achieved. Upper contact layers 11 and/or 21 may be of or include NiCr, NiCrOx and/or the like in different example embodiments of this invention.
Dielectric layer 23 may be of or include tin oxide in certain example embodiments of this invention. However, layer 23 is optional and need not be provided in certain example embodiments of this invention. Silicon nitride overcoat layer 25 may be initially deposited by sputtering or IBAD, and may be ion beam treated in any manner discussed herein.
Other layer(s) below or above the illustrated coating may also be provided. Thus, while the layer system or coating is “on” or “supported by” substrate 1 (directly or indirectly), other layer(s) may be provided therebetween. Thus, for example, the coating of FIG. 3 may be considered “on” and “supported by” the substrate 1 even if other layer(s) are provided between layer 3 and substrate 1. Moreover, certain layers of the illustrated coating may be removed in certain embodiments, while others may be added between the various layers or the various layer(s) may be split with other layer(s) added between the split sections in other embodiments of this invention without departing from the overall spirit of certain embodiments of this invention.
FIG. 7 is a flowchart illustrating how an IR reflecting layer 9 and/or 19 may be formed according to another example embodiment of this invention. In the FIG. 7 embodiment, an IR reflecting layer may be formed entirely using IBAD. At the beginning of the IR reflecting layer formation using IBAD, the volts applied to the ion source are low or zero so that the ion beam either is not formed or is of a low energy type (i.e., low eV per ion). Then, during formation of the IR reflecting layer after at least some of the layer has been deposited, the voltage at the ion source is increased so as to increase the eV per ion in the ion beam. In other words, the ion energy is increased, either progressively or in a step-like manner, during formation of the IR reflecting layer. This prevents or reduces damage to the lower portion of the IR reflecting layer and/or to the layer under the same since a low energy ion beam is used to form the initial part of the IR reflecting layer, and yet achieves the advantages discussed herein with respect to the final IR reflecting layer since a higher energy is used to form at least the upper portion of the IR reflecting layer.
Referring in detail to FIG. 7, one or more underlying layer(s) are deposited on substrate 1 (ST1). This step is similar to step S1 in the FIG. 1 embodiment. Then, during the deposition of the first portion of the IR reflecting layer (9 and/or 19), IBAD is used but the ion beam is characterized by a relatively low energy (ST2). For example, in ST2 during the formation of the initial portion of the IR reflecting layer, an ion energy of from about 0 to 200 eV per Ar+ ion, more preferably from about 1 to 150 eV, more preferably from about 5 to 100 eV per Ar+ ion is used. Again, other inert gas(es) may be used instead of or in addition to argon. Then, after part of the IR reflecting layer has been formed, the ion energy is increased for forming the additional or remainder portion of the IR reflecting layer(s) 9 and/or 19 via IBAD (ST3). In certain example embodiments, the ion energy is increased to an ion energy of from about 150 to 700 eV per Ar+ ion, more preferably of from about 200 to 600 eV per Ar+ ion, and most preferably about 500 eV per Ar+ ion in ST3. In certain example embodiments of this invention, the ion energy is increased by at least about 10% in step ST3, more preferably at least about 25%, even more preferably at least about 50%, sometimes at least about 100%. After the additional and/or remainder portion of the IR reflecting layer has been formed using the higher ion energy, additional layer(s) are deposited/formed on the substrate 1 over at least the IR reflecting layer (ST4).
While various thicknesses and materials may be used in layers in different embodiments of this invention, example thicknesses and materials for the respective layers on the glass substrate 1 in the FIG. 3 embodiment are as follows, from the glass substrate 1 outwardly. One or both of the IR reflecting layers 9 and/or 19 are formed/deposited using at least IBAD according to any of the embodiments discussed herein.










Example Materials/Thicknesses; FIG. 3 Embodiment










Layer
Preferred
More



Glass (1-10 mm thick)
Range ({acute over (Å)})
Preferred ({acute over (Å)})
Example (Å)















Si3N4 (layer 3)
40-450
Å
70-250
Å
100


ZnOx (layer 7)
10-300
{acute over (Å)}
40-150
{acute over (Å)}
100


Ag (layer 9) (IBAD)
50-250
{acute over (Å)}
80-120
{acute over (Å)}
98


NiCrOx (layer 11)
10-100
{acute over (Å)}
30-45
{acute over (Å)}
35


SnO2 (layer 13)
0-1,000
Å
350-630
Å
570


SixNy (layer 14)
50-450
{acute over (Å)}
90-150
{acute over (Å)}
120


ZnOx (Layer 17)
10-300
{acute over (Å)}
40-150
{acute over (Å)}
95


Ag (layer 19)(IBAD)
50-250
{acute over (Å)}
80-220
{acute over (Å)}
96


NiCrOx (layer 21)
10-100
{acute over (Å)}
30-45
{acute over (Å)}
35


SnO2 (layer 23)
0-750
Å
150-300
Å
200


Si3N4 (layer 25)
10-750
{acute over (Å)}
100-320
{acute over (Å)}
180









Optionally, one or both of silicon nitride inclusive layers 3 and/or 25 may be ion beam treated in certain example embodiments of this invention. Ion beam treatment of silicon nitride inclusive layer 3 has surprisingly been found to reduce sodium migration during optional heat treatment thereby improving coating characteristics, whereas ion beam treatment of silicon nitride overcoat layer 25 has been found to improve durability of the resulting coated article.
In certain IBAD embodiments, if the appropriate ion energy is used for a given material, the compressive stress of the IBAD-deposited layer 3, 9, 19, and/or 25 may be from about 50 MPa to 2 GPa, more preferably from about 50 MPa to 1 GPA, and most preferably from about 100 MPa to 800 MPa. Such IBAD techniques may be used in conjunction with IR reflecting layer(s), base layer(s), overcoat layer(s) or any other layer herein which may be ion beam treated.
In various embodiments discussed herein, the ion beam may be a focused ion beam, a collimated ion beam, or a diffused ion beam in different embodiments of this invention.
Coated articles according to different embodiments of this invention may or may not be heat treated (HT) in different instances. The terms “heat treatment” and “heat treating” as used herein mean heating the article to a temperature sufficient to achieve thermal tempering, heat bending, and/or heat strengthening of the glass inclusive article. This definition includes, for example, heating a coated article in an oven or furnace at a temperature of least about 580 degrees C., more preferably at least about 600 degrees C., for a sufficient period to allow tempering, bending, and/or heat strengthening. In certain instances, the HT may be for at least about 4 or 5 minutes. In certain example embodiments of this invention, ion beam treated silicon nitride undercoat and/or overcoat layers are advantageous in that they change less with regard to color and/or transmission during optional heat treatment; this can improve interlayer adhesion and thus durability of the final product; and ion beam treated lower silicon nitride inclusive layers aid in reduction of sodium migration during HT.
It is noted that any of the silicon nitride layers 3 and/or 25 to be ion beam treated herein may be initially sputter deposited in any suitable stoichiometric form including but not limited to Si3N4 or a Si-rich type of silicon nitride. Example Si-rich types of silicon nitride are discussed in U.S. 2002/0064662 (incorporated herein by reference), and any Si-rich layer discussed therein may be initially sputter-deposited herein for any suitable silicon nitride layer. Also, silicon nitride layers herein may of course be doped with aluminum (e.g., 1-10%) or the like in certain example embodiments of this invention. It has also been found that ion beam treating of a layer comprising silicon nitride (3 and/or 25) increases the hardness of such a layer according to certain example embodiments of this invention (e.g., via IBAD or peening). A layer comprising silicon nitride when conventionally sputtered typically has a hardness of from 10-14 GPa. In certain example embodiments of this invention however, when ion beam treated, the silicon nitride layer (3 and/or 25) realizes a hardness of at least 20 GPa, more preferably of at least 22 GPa, and most preferably of at least 24 GPa.
In certain example embodiments of this invention, one or both of NiCr or NiCrOx layers 11 and/or 21 may be ion beam treated using at least oxygen ions in order to oxidation grade as described in U.S. Ser. No. 10/847,672, filed May 18, 2004, the entire disclosure of which is hereby incorporated herein by reference.
FIGS. 4-5 illustrate an exemplary linear or direct ion beam source 26 which may be used to form the additional or remainder portion of an IR reflecting layer (9 and/or 19) as discussed above in connection with FIGS. 1-3, or to ion beam treat layer(s) 3 and/or 25 with at least nitrogen ions in certain example embodiments of this invention (via peening or IBAD). Ion beam source (or ion source) 26 includes gas/power inlet 31, racetrack-shaped anode 27, grounded cathode magnet portion 28, magnet poles, and insulators 30. An electric gap is defined between the anode 27 and the cathode 29. A 3 kV or any other suitable DC power supply may be used for source 26 in some embodiments. The gas(es) discussed herein for use in the ion source during the ion beam treatment may be introduced into the source via gas inlet 31, or via any other suitable location. Ion beam source 26 is based upon a known gridless ion source design. The linear source may include a linear shell (which is the cathode and grounded) inside of which lies a concentric anode (which is at a positive potential). This geometry of cathode-anode and magnetic field 33 may give rise to a close drift condition. Feedstock gases (e.g., nitrogen, argon, a mixture of nitrogen and argon, etc.) may be fed through the cavity 41 between the anode 27 and cathode 29. The electrical energy between the anode and cathode cracks the gas to produce a plasma within the source. The ions 34 (e.g., nitrogen ions) are expelled out (e.g., due to the nitrogen gas in the source) and directed toward the layer to be ion beam treated/formed in the form of an ion beam. The ion beam may be diffused, collimated, or focused. Example ions 34 in beam (B) are shown in FIG. 4.
A linear source as long as 0.5 to 4 meters may be made and used in certain example instances, although sources of different lengths are anticipated in different embodiments of this invention. Electron layer 35 is shown in FIG. 4 and completes the circuit thereby permitting the ion beam source to function properly. Example but non-limiting ion beam sources that may be used are disclosed in U.S. Pat. Document Nos. 6,303,226, 6,359,388, and/or 2004/0067363, all of which are hereby incorporated herein by reference.
In certain example embodiments of this invention, coated articles herein having two IR reflecting layer 9, 19 may have the following optical and solar characteristics when measured monolithically (before any optional HT). The sheet resistances (Rs) herein take into account all IR reflecting layers (e.g., silver layers 9, 19).










Optical/Solar Characteristics (Monolithic double-Ag; pre-HT)












Characteristic
General
More Preferred
Most Preferred







Rs (ohms/sq.):
<=5.0
<=3.5
<=2.5



En:
<=0.08
<=0.03
<=0.025



Tvis (Ill. C 2°):
>=70%
>=75%
>=75.5%










In certain example embodiments, coated articles herein may have the following characteristics, measured monolithically for example, after heat treatment (HT):










Optical/Solar Characteristics (Monolithic double-Ag; post-HT)












Characteristic
General
More Preferred
Most Preferred







Rs (ohms/sq.):
<=5.0
<=3.0
<=2.0



En:
<=0.07
<=0.03
<=0.0025



Tvis (Ill. C 2°):
>=70%
>=75%
>=80%



Haze:
<=0.40
<=0.35
<=0.30










It is noted, however, that for coatings having only one IR reflecting layer, the sheet resistance and emissivity values will of course be higher.
Moreover, in certain example laminated embodiments of this invention, coated articles herein which have been heat treated to an extent sufficient for tempering and/or heat bending, and which have been laminated to another glass substrate, may have the following optical/solar characteristics:










Optical/Solar Characteristics (Laminated double-Ag; post-HT)










Characteristic
General
More Preferred
Most Preferred





Rs (ohms/sq.):
<=5.0
<=3.0
<=2.0


En:
<=0.07
<=0.03
<=0.025


Tvis (Ill. D65 10°):
>=70%
>=75%
>=77%


Haze:
<=0.45
<=0.40
<=0.36









Moreover, coated articles including coatings according to certain example embodiments of this invention have the following optical characteristics (e.g., when the coating(s) is provided on a clear soda lime silica glass substrate 1 from 1 to 10 mm thick; e.g., 2.1 mm may be used for a glass substrate reference thickness in certain example non-limiting instances) (laminated).










Example Optical Characteristics (Laminated double-Ag: post-HT)











Characteristic
General
More Preferred







Tvis (or TY)(Ill. D65 10°):
>=75%
>=77%



a*t (Ill. D65 10°):
−6 to +1.0
−4 to 0.0



b*t (Ill. D65 10°):
−2.0 to +8.0
0.0 to 4.0



L* (Ill. D65 10°):
88-95
90-95



RfY (Ill. C, 2 deg.):
1 to 12%
1 to 10%



a*f (Ill. C, 2°):
−5.0 to +2.0
−3.5 to +0.5



b*f (Ill. C, 2°):
−14.0 to +10.0
−10.0 to 0



L* (Ill. C 2°):
30-40
33-38



RgY (Ill. C, 2 deg.):
1 to 12%
1 to 10%



a*g (Ill. C, 2°):
−5.0 to +2.0
−2 to +2.0



b*g (Ill. C, 2°):
−14.0 to +10.0
−11.0 to 0



L* (Ill. C 2°):
30-40
33-38










The following examples are provided for purposes of example only and are not intended to be limiting.
EXAMPLES
In Example 1, an IR reflecting layer of Ag was formed on a 100 Å thick ZnO layer. In forming the IR reflecting layer, an Ag seed layer about 60 Å thick was first deposited via sputtering, and thereafter the remainder of the IR reflecting layer was formed using IBAD. The IBAD, at room temperature, utilized a silver sputtering target and an ion beam of argon ions, where the average ion energy was from about 200 to 250 eV per Ar+ ion.
Comparative Example 1 was the same as Example 1 above, except that the entire Ag IR reflecting layer was formed using only sputtering (no IBAD was used). The results comparing Example 1 and Comparative Example are set forth below.














Ex. 1
Comparative Ex. 1


















Ag Thickness (total):
120 Å
120 Å


Sheet Resistance (Rs, ohms/square):
3.0
3.8


IBAD:
yes
no


Ion Energy per Ar+ ion:
200-250 eV
0


Stress Type:
compressive
tensile









It can be seen from the above that the use of IBAD (see Example 1) in helping form the IR reflecting layer resulted in a significantly improved (i.e., lower) sheet resistance of the IR reflecting layer. Indeed, the sheet resistance (Rs) was about 21% lower in Example 1 where IBAD was used, than in Comparative Example 1 where only sputtering was used to form the IR reflecting layer (3.8−3.0=0.8: and 0.8/3.8=21%). In certain example embodiments of this invention, the use of IBAD causes the sheet resistance (Rs) to be at least about 5% lower than if ion beam treatment such as IBAD had not been used, more preferably at least about 10% lower, sometimes at least 15% lower, and even at least 20% lower in certain instances. Moreover, the compressive stress of the IR reflecting layer of Example 1 resulted in significantly improved durability compared to Comparative Example 1, since Comparative Example 1 had tensile stress due to its deposition using only sputtering.
In Example 2, an IR reflecting layer of Ag about 139 Å thick was formed on a 600 Å thick ZnO layer. In forming the IR reflecting layer, an Ag seed layer portion about 60 Å thick was first deposited via sputtering, and thereafter the remainder of the IR reflecting layer was formed using IBAD. The IBAD, at room temperature, utilized a silver sputtering target and an ion beam of argon ions, where the average ion energy was about 250 eV per Ar+ ion.
Comparative Example 2 was the same as Example 2, except that the entire Ag IR reflecting layer was formed using sputtering without IBAD.
Comparative Example 3 did not include a seed layer, and instead used IBAD at the same ion energy to deposit the entire Ag IR reflecting layer.















Ex. 2
Comp Ex. 2
Comp Ex. 3



















Ag Thickness (total):
139 Å
153 Å
144 Å


Bulk Resistivity [μΩ cm]:
4.6
4.8
4.9


Seed layer
yes
no
no


IBAD:
yes
no
yes


Ion Energy per Ar+ ion:
250 eV
0
250 eV


Stress Type:
compressive
tensile
compressive









It can be seen from the above that the use of IBAD (see Example 2) in helping form the IR reflecting layer resulted in an improved (i.e., lower) resistance of the IR reflecting layer compared to only sputtering in Comparative Example. It is noted that the bulk resistance (BR) in the chart above can be converted to sheet resistance as follows: Rs=BR/d, where “d” is the thickness of the IR reflecting layer. Moreover, the compressive stress of the IR reflecting layer of Example 2 resulted in significantly improved durability compared to Comparative Example 2, since Comparative Example 2 had tensile stress due to its deposition using only sputtering.
The comparison between Example 2 and Comparative Example 3 illustrates the benefit of the Ag seed layer. In particular, when the seed layer was not present and the same rather high ion energy was used to deposit the entire Ag IR reflecting layer via IBAD, the electrical resistivity actually was worse (higher) than with only sputtering (compare Comparative Example 3 with Comparative Example 2). It is believed that this occurred since the high ion energy used at the beginning of forming the IR reflecting layer caused significant ion mixing with the underlying ZnO and thereby damaged the structure of the resulting IR reflecting layer. This illustrates the advantage of the FIG. 7 embodiment where IBAD can be used to form the entire IR reflecting layer, except that ion energy is increased during deposition of the layer so that such damage to lower portions of the layer does not occur or is reduced.
The following examples relate to ion beam treatment (either via IBAD or peening) of silicon nitride layer (e.g., layers 3 and/or 25 for example and without limitation).
Examples 3-5 illustrate example techniques for forming layers 3 and/or 25, or any other suitable layer according to example embodiments of this invention. Examples 3-5 utilized IBAD type of ion beam treatment, and were made and tested as follows. A silicon nitride layer was deposited on a quartz wafer (used for ease of stress testing) using IBAD (e.g., see FIG. 6) under the following conditions in the deposition chamber: pressure of 2.3 mTorr; anode/cathode ion beam source voltage of about 800 V; Ar gas flow in the ion source of 15 sccm; N2 gas flow in the ion source 26 of 15 sccm; sputtering target of Si doped with about 1% boron; 460 V applied to sputtering cathode; 5.4 sputtering amps used; 60 sccm Ar and 40 sccm N2 gas flow used for sputtering gas flow; linear line speed of 50 inches/minute; where the quartz wafer substrate was circular in shape and about 0.1 to 0.15 mm thick. The ion beam treatment time for a given area was about 3 seconds.
Example 4 was the same as Example 3, except that the anode/cathode voltage in the ion source was increased to 1,500 V.
Example 5 was the same as Example 3, except that the anode/cathode voltage in the ion source was increased to 3,000 V.
The stress results of Examples 3-5 were as follows, and all realized compressive stress:














Ion Source


Example
Compressive Stress
Anode/Cathode Volts



















3
750
MPa
800
V


4
1.9
GPa
1,500
V


5
1
GPa
3,000
V









It can be seen from Examples 3-5 that the compressive stress of the silicon nitride layer realized due to IBAD deposition is a function of ion energy (i.e., which is a function of voltage applied across the anode/cathode of the ion source 26). In particular, 1,500 anode-cathode volts caused the highest compressive stress to be realized, whereas when too much voltage was applied the stress value began moving back toward tensile.
Example 6
Example 6 used post-sputtering peening type of ion beam treatment, and was made and tested as follows. A silicon nitride layer about 425 Å thick was deposited by conventional magnetron-type sputtering using a Si target doped with Al on a substrate. After being sputter-deposited, the silicon nitride layer had a tensile stress of 400 MPa as tested on the quartz wafer. After being sputter-deposited and stress tested, the silicon nitride layer was ion beam treated using an ion source 26 as shown in FIGS. 4-5 under the following conditions: ion energy of 750 eV per N ion; treatment time of about 18 seconds (3 passes at 6 seconds per pass); and N2 gas used in the ion source. After being ion beam treated, the silicon nitride layer was again tested for stress, and had a tensile stress of only 50 MPa. Thus, the post-sputtering ion beam treatment caused the tensile stress of the silicon nitride layer to drop from 400 MPa down to 50 MPa (a drop of 87.5%).
Example 7
The following hypothetical Example 7 is provided for purposes of example only and without limitation, and uses a 2.1 mm thick clear glass substrates so as to have approximately the layer stack set forth below and shown in FIG. 3. The layer thicknesses are approximations, and are in units of angstroms (Å).














Layer




Glass Substrate
Thickness (Å)



















N-doped Si3N4
100



ZnAlOx
109



Ag
96



NiCrOx
25



SnO2
535



SixNy
126



ZnAlOx
115



Ag
95



NiCrOx
25



SnO2
127



N-doped Si3N4
237










The processes used in forming the coated article of Example 7 are set forth below. The sputtering gas flows (argon (Ar), oxygen (O), and nitrogen (N)) in the below table are in units of sccm (gas correction factor of about 1.39 may be applicable for argon gas flows herein), and include both tuning as and gas introduced through the main. The line speed was about 5 m/min. The pressures are in units of mbar×10−3. The silicon (Si) targets, and thus the silicon nitride layers, were doped with aluminum (Al). The Zn targets in a similar manner were doped with about 2% Al. IBAD was used in forming each of the Ag IR reflecting layers, and also for the upper and lower silicon nitride layers.
Sputtering Process Used in Example 7

















Cathode
Target
Power(kW)
Ar
O
N
Volts
Pressure
















IBAD
N-doped Si3N4 layer 3 formed using any of Examples 3-6














C14
Zn
19.5
250
350
0
276
2.24


C15
Zn
27.8
250
350
0
220
1.88








C24
Process of any of Examples 1-2














C25
NiCr
16.5
350
0
0
510
2.33


C28
Sn
27.3
250
454
350
258
2.30


C29
Sn
27.3
250
504
350
246
1.97


C39
Sn
30
250
548
350
257
2.29


C40
Sn
28.5
250
458
350
245
2.20


C41
Sn
30.8
250
518
350
267
2.45


C43
Si
59.7
350
0
376
285
2.47


C45
Zn
26.9
250
345
0
209
3.78


C46
Zn
26.8
250
345
0
206
1.81








C49
Process of any of Examples 1-2














C50
NiCr
16.6
250
75
0
575
1.81


C54
Sn
47.3
250
673
350
314
1.92








IBAD
N-doped Si3N4 layer 25 formed using any of Examples 3-6









It can be seen that in the aforesaid Example 7 both of silicon nitride layers 3 and 25 were ion beam treated in a manner so as to cause N-doping of N-doped Si3N4 to occur in each of the layers, and both of the IR reflecting layers were at least partially formed using IBAD.
After being sputter deposited onto the glass substrates, the hypothetical Example 7 coated article was heat treated in a manner sufficient for tempering and heat bending, and following this heat treatment had the following characteristics as measured in monolithic form.
Characteristics of Example 7 (Monolithic; Post—HT)














Characteristic
Example 7



















Visible Trans. (Tvis or TY)(Ill. C 2 deg.):
80.0%



a*
−4.8



b*
10.7



Glass Side Reflectance (RY)(Ill C, 2 deg.):
8.3%



a*
−3.5



b*
7.8



Film Side Reflective (FY)(Ill. C, 2 deg.):
7.5%



a*
−5.8



b*
14.2



Rs (ohms/square) (pre-HT):
2.74



Rs (ohms/square) (post-HT):
2.07



Haze:
0.28










The coated article of Example 7 was then laminated to another corresponding heat treated and bent glass substrate to form a laminated vehicle windshield product. Following the lamination, the resulting coated article laminate (or windshield) had the following characteristics.
Characteristics of Example 7 (Laminated; Post—HT)














Characteristic
Example 7









Visible Trans. (Tvis or TY)(Ill. D65 10°):
77.8%



a*
−3.1



b*
3.5



Glass Side Reflectance (RY)(Ill C, 2 deg.):
 9.0%



a*
1.5



b*
−9.1



Film Side Reflective (FY)(Ill. C, 2 deg.):
 8.9%



a*
−1.1



b*
−7.8



Rs (ohms/square):
see above



Haze:
0.32










FIGS. 8-9 illustrate another example embodiment of this invention. This embodiment is similar to those above, except that the ion beam treatment of the IR reflecting layer 9 is performed at least after the IR reflecting layer has been originally deposited by sputter-deposition or the like (this may be referred to as “peening” in certain instances). In this embodiment, details concerning various layers can be ascertained in view of the discussion above regarding the like numbered layers. The example layer stack shown in FIG. 9 is glass/zinc oxide/silver/nickel-chrome oxide/tin oxide.
Referring to FIGS. 8-9, an example process for making such a coated article will be described for purposes of example and without limitation. Glass substrate 1 is initialy provided (S100). Then, at least one underlayer 7 (e.g., of or including zinc oxide or any other suitable material) is formed on the substrate either directly thereon or on the substrate over other layer(s) (S102). IR reflecting layer 9 (e.g., of or including Ag, Au or the like) is then sputter-deposited on the substrate 1 over the underlying layer(s) 7 (S104). Typically, in this embodiment, IBAD is not used during formation of layer 9, although in certain alternative instances it may be possible to do so.
After the IR reflecting layer 9 has been originally or initially formed via sputtering or the like, the IR reflecting layer 9 is then ion beam treated (S106). For example, see the ion beam source discussed above in connection with FIGS. 4-5. In certain example embodiments, the ion beam treatment of layer 9 may be performed using ions from an inert gas such as Ar and/or Kr. Moreover, in certain example instances, this treatment may be performed in a manner so as to cause the IR reflecting layer to realize compressive stress (as opposed to tensile resulting from mere sputtering). In other words, the ion beam treatment may cause the stress of the layer 9 to switch from tensile to compressive, or alternative to significantly reduce its tensile stress while remaining tensile in certain instances. Following the ion beam treatment (peening) of the IR reflecting layer 9 in S106, one or more additional layers 11, 13 and/or 23 may then be formed on the substrate 1 over the ion beam treated IR reflecting layer (S108).
Still referring to the FIG. 8-9 embodiment, the ion beam treatment may in certain embodiments result in an IR reflecting layer 9 that is graded with respect to argon and/or krypton content. In particular, an upper portion of the IR reflecting layer 9 includes a higher Ar and/or Kr concentration than does a lower portion of the IR reflecting layer. This is because Ar and/or Kr ions from an ion beam do not impinge upon the layer during formation thereof until after the layer has been originally or initially formed by sputter-deposition. Accordingly, the upper portion of the resulting IR reflecting layer 9 includes a higher Ar and/or Kr content than does the lower portion of the layer. This grading would be for content of another element (e.g., Xe) if the other element(s) was used instead of or in place of Ar and/or Kr in the ion beam in alternative embodiments of this invention. In certain example embodiments, an upper portion of the IR reflecting layer 9 has an Ar and/or Kr (or other inert element) concentration at least 10% higher than that of another portion (e.g., a lower portion) of the IR reflecting layer located therebelow, more preferably at least 20% higher, and most preferably at least 30% higher. The example “lower portion” is merely some arbitrarily selected portion of the layer at least partially below the center point and/or below the upper portion of the layer, where the “upper portion” of the layer is some arbitrarily selected portion of the layer at least partially above the center of the layer. In certain example instances, the upper portion may be the upper 20 Å of the IR reflecting layer, and the lower portion may be the lower 60 Å (or 20 Å) of the layer. The lower portion of the layer may even have an Ar and/or Kr content of 0 in certain instances.
Example ion beam treatment techniques for the FIG. 8-9 embodiment are discussed above with respect to other embodiments of this invention.
Additional Examples
Both Example 8 (Ex. 8) and Comparative Example 8 (Comp. Ex. 8) had the following layer stack, using 4.0 mm clear glass, where the layers are listed from the glass substrate moving outwardly:














Ex. 8 & Comp. Ex. 8 Layers
Thickness (angstroms)









zinc-aluminum oxide
122



silver
120



nickel-chrome oxide
2-25



tin oxide
124










The difference between Example 8 and Comparative Example 8 was that ion beam treatment (peening type) was used on the silver in Example 8 but not in Comparative Example 8. All layers were originally deposited by sputtering. While no ion beam treatment was performed for Comparative Example 8, the ion beam treatment in Example 8 of the silver layer (after it was sputter-deposited) used the following parameters: 300 ml Kr gas flow in ion beam source; 0.3 A current in ion source (99 W power). Thus, the ion beam for Example 8 consisted of or consisted essentially of Kr ions. The results comparing Example 8 and Comparative Example 8 are set forth below.














Ex. 8
Comparative Ex. 8


















Sheet Resistance (Rs, ohms/square):
3.5
3.7


Ion beam treat Ag?:
yes
no


Emittance (normal):
3.51%
4.07%


Stress Type:
compressive
tensile









It can be seen from the above that the use of the ion beam treatment of the silver (see Example 8) improved (i.e., lowered) sheet resistance and emittance of the IR reflecting layer 9, and switched the stress of the layer to compressive which may be advantageous for durability purposes.
Both Example 9 (Ex. 9) and Comparative Example 9 (Comp. Ex. 9) had the following layer stack, using 4.0 mm clear glass, where the layers are listed from the glass substrate moving outwardly:
Example 9
silicon nitride
zinc-aluminum oxide
silver
nickel-chrome oxide
silicon nitride
tin oxide
The difference between Example 9 and Comparative Example 9 was that ion beam treatment (peening type) was used on the silver in Example 9 but not in Comparative Example 9. All layers were originally deposited by sputtering. While no ion beam treatment was performed for Comparative Example 9, the ion beam treatment in Example 9 of the silver layer (after it was sputter-deposited) used the following parameters: 300 ml Kr gas flow in ion beam source; 0.4 A current in ion source. Thus, the ion beam for Example 9 consisted of or consisted essentially of Kr ions. The results comparing Example 9 and Comparative Example 9 are set forth below.














Ex. 9
Comparative Ex. 9


















Sheet Resistance (Rs, ohms/square):
3.9
3.9


Ion beam treat Ag?:
yes
no


Emittance (normal):
4.18%
4.30%


Stress Type:
compressive
tensile









It can be seen from the above that the use of the ion beam treatment of the silver (see Example 9) improved (i.e., lowered) emittance of the IR reflecting layer 9, and switched the stress of the layer to compressive which may be advantageous for durability purposes.
While the aforesaid Examples ion beam treat layers comprising silicon nitride and/or silver, this invention is not so limited. Other layers may be ion beam treated in a similar manner.
In certain other embodiments of this invention, any of the aforesaid embodiments may be applied to other coatings. For example and without limitation, any of the aforesaid embodiments may also be applied to coated articles and thus solar control coatings of one of more of U.S. Pat. Document Nos. 2003/0150711, 2003/0194570, 6,723,211, 6,576,349, 5,514,476, 5,425,861, all of which are hereby incorporated herein by reference.
While many of the above-listed embodiments are used in the context of coated articles with solar control coatings, this invention is not so limited. For example, ion beam treating of layers as discussed herein may also be used in the context of other types of product and coatings relating thereto.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

## Claims

1. A method of making a coated article, the method comprising:
providing a glass substrate;
forming at least one dielectric layer on the substrate;
forming an infrared (IR) reflecting layer on the substrate over at least the first dielectric layer, where said forming of the IR reflecting layer comprises ion beam treating the IR reflecting layer, and wherein a voltage at an ion source used for said ion beam treating is increased during formation of the IR reflecting layer; and
forming at least one additional dielectric layer on the substrate over at least the IR reflecting layer.

2. The method of claim 1, wherein said at least one dielectric layer comprises at least one of silicon nitride and zinc oxide.

3. The method of claim 1, wherein said additional dielectric layer comprises at least one of tin oxide and silicon nitride.

4. The method of claim 1, wherein said ion beam consists essentially of ions from an inert gas used in an ion source(s).

5. The method of claim 1, wherein said ion beam is substantially free of oxygen ions.

6. The method of claim 1, wherein the ion beam is utilized in a manner so as to cause the IR reflecting layer to have compressive stress.

7. The method of claim 1, further comprising forming at least a layer comprising NiCr on the substrate over at least the IR reflecting layer.

8. The method of claim 1, wherein the ion beam is utilized in a manner sufficient to cause a sheet resistance (Rs) and/or emissivity of the IR reflecting layer to be less than if the ion beam had not been used.

9. The method of claim 1, wherein the IR reflecting layer is initially deposited by sputtering at least one target, and wherein said ion beam treating is performed by directing ions at the IR reflecting layer after the layer has been initially deposited by sputtering.

10. The method of claim 1, wherein the ion beam is utilized in a manner sufficient to cause a sheet resistance (Rs) and/or emissivity of the IR reflecting layer to be at least 5% less than if the ion beam had not been used.

11. The method of claim 1, further comprising heat treating the coated article in a manner sufficient for at least one of tempering and heat bending, so that following said heat treating the coated article has a visible transmission of at least 70% and a sheet resistance (Rs) of no greater than 5.0 ohms/square.

12. The method of claim 1, further comprising heat treating the coated article in a manner sufficient for at least one of tempering and heat bending, so that following said heat treating the coated article has a visible transmission of at least 75% and a sheet resistance (Rs) of no greater than 3.0 ohms/square.

13. The method of claim 1, wherein prior to any optional heat treating, the coated article in monolithic form has a visible transmission of at least 70% and a sheet resistance (Rs) of no greater than 5.0 ohms/square.

14. The method of claim 1, further comprising forming a layer comprising zinc oxide on the glass substrate in a position so that the IR reflecting layer is formed directly on and contacting the layer comprising zinc oxide, and wherein the IR reflecting layer comprises silver.

15. The method of claim 1, further comprising forming another IR reflecting layer comprising silver.

16. The method of claim 1, wherein the infrared (IR) reflecting layer has a first layer portion and second layer portion and each of the first layer portion and the second layer portion is substantially metallic.

17. The method of claim 1, wherein said ion beam treating of the IR reflecting layer comprises using a simultaneous combination of an ion beam and material moving toward the substrate from a sputtering target used in forming the IR reflecting layer.

18. The method of claim 1, wherein the IR reflecting layer comprises silver.