(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2001/0041252 A1
`(43) Pub. Date:
`Nov. 15, 2001
`Laird
`
`US 2001 0041252A1
`
`(54) LOW-EMISSIVITY GLASS COATINGS
`HAVING ALAYER OF NITRDED
`NCHROME AND METHODS OF MAKING
`SAME
`
`(76) Inventor: Ronald E. Laird, Washtenaw, MI (US)
`Correspondence Address:
`NXON & VANDERHYE PC.
`8th Floor
`1100 North Glebe Road
`Arlington, VA 22201 (US)
`(21) Appl. No.:
`09/797,903
`(22) Filed:
`Mar. 5, 2001
`Related U.S. Application Data
`(63) Non-provisional of provisional application No.
`60/187,039, filed on Mar. 6, 2000.
`
`Publication Classification
`
`(51) Int. Cl. .................................................. B32B 15/04
`
`(52) U.S. Cl. ......................... 428/216; 428/432; 428/472;
`428/702; 428/698; 428/336
`ABSTRACT
`(57)
`Low-E glass coated glass articles are comprised of a glass
`Substrate and a multiple layer coating on a Surface of the
`glass Substrate. Relatively high light transmissivity of
`greater than about 72% and Satisfactory color characteristics
`are achieved. The coating includes a layer of a transparent
`dielectric material adjacent the Surface of the glass Substrate,
`and respective layers of nitrided nichrome and Silver each of
`which are formed by Sputter-coating onto the glass Substrate
`in a nitrogen-containing atmosphere. Most preferably, the
`coating also includes a layer of Silicon oxynitride interposed
`between the layer of dielectric material and the layer of
`nitrided nichrome. The Silicon oxynitride layer may include
`an oxygen gradient layer wherein the concentration of
`oxygen decreases from one location in the Silicon oxynitride
`layer to another location at a different depth in that same
`layer. If present, the oxygen gradient is most preferably Such
`that the greater amount of oxygen concentration is nearer the
`bottom of the layer (i.e., towards the glass Substrate) with the
`lesser amount of oxygen concentration being nearer the top
`of the layer (i.e., away from the glass layer).
`
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`Page 1 of 8
`
`APPLIED MATERIALS EXHIBIT 1034
`
`

`

`Patent Application Publication Nov. 15, 2001 Sheet 1 of 3
`
`US 2001/0041252 A1
`
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`Page 2 of 8
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`

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`Patent Application Publication Nov. 15, 2001 Sheet 2 of 3
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`

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`Patent Application Publication Nov. 15, 2001 Sheet 3 of 3
`
`US 2001/0041252 A1
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`

`

`US 2001/0041252A1
`
`Nov. 15, 2001
`
`LOW-EMISSIVITY GLASS COATINGS HAVING A
`LAYER OF NITRDED NICHROME AND
`METHODS OF MAKING SAME
`
`CROSS-REFERENCE TO RELATED
`APPLICATION
`0001. This application is based on, and claims domestic
`priority benefits under 35 USC S119(e) from, U.S. Provi
`sional Application No. 60/187,039 filed on Mar. 6, 2000, the
`entire content of which is expressly incorporated hereinto by
`reference.
`
`FIELD OF THE INVENTION
`0002 The present invention relates generally to coatings
`for glass Substrates. More specifically, the present invention
`relates to glass Substrate coatings which exhibit low emis
`Sivity (So-called “low-E’ coatings) and Substantially no
`color characteristics.
`
`BACKGROUND AND SUMMARY OF THE
`INVENTION
`0.003 Low-E coatings for glass are well known. In this
`regard, commonly owned U.S. Pat. Nos. 5,344,718, 5,425,
`861, 5,770,321, 5,800,933 (the entire content of each being
`incorporated expressly herein by reference) disclose coat
`ings formed of a multiple layer coating “system”. Generally,
`Such conventional multiple layer low-E glass coatings have
`a layer of a transparent dielectric material (e.g., TiO2, BiO,
`PbO or mixtures thereof) adjacent the glass substrate and a
`Sequence of multiple layers of, for example, SiN., nickel
`(Ni), nichrome (Ni:Cr), nitrided nichrome (NiCrM) and/or
`silver (Ag). These conventional low-E coatings are, more
`over, heat-treatable-that is, the coating is capable of being
`Subjected to the elevated temperatures associated with con
`ventional tempering, bending, heat-strengthening or heat
`Sealing processes without significantly adversely affecting
`its desirable characteristics.
`0004. While the conventional low-E coating systems
`disclosed in the above-cited U.S. patents are Satisfactory,
`there exists a continual need to improve various properties
`of low-E coating Systems generally. For example, continued
`improvements in the durability and/or color (or more accu
`rately, lack of color) characteristics in low-E glass coatings
`are desired. Improvements in Such characteristics are impor
`tant to ensure that the coatings retain their low-E property
`for prolonged periods of time (even after being Subjected to
`potentially abrasive environment encountered during the
`manufacturing proceSS-e.g., the Washing and cutting of
`glass articles having Such low-E coatings) and have the
`desired light transmission properties. It is toward fulfilling
`Such needs that the present invention is directed.
`0005 Broadly, the present invention is embodied in
`low-E glass coated glass articles comprised of a glass
`Substrate and a multiple layer coating on a Surface of the
`glass Substrate, wherein the coating includes a layer of a
`transparent dielectric material adjacent the Surface of the
`glass Substrate, a layer of nitrided nichrome, and a layer of
`Silver which is Sputter coated onto the glass Substrate in a
`nitrogen-containing atmosphere. Most preferably, the coat
`ing further includes a layer of Silicon oxynitride interposed
`between the layer of dielectric material and the layer of
`nitrided nichrome.
`0006 These and other aspects and advantages will
`become more apparent after careful consideration is given to
`the following detailed description of the preferred exem
`plary embodiments thereof.
`
`BRIEF DESCRIPTION OF THE
`ACCOMPANYING DRAWINGS
`
`0007 Reference will hereinafter be made to the accom
`panying drawings, wherein like reference numerals through
`out the various FIGURES denote like structural elements,
`and wherein;
`0008 FIG. 1 is a is a greatly enlarged cross-sectional
`Schematic representation of a Surface-coated glass article of
`this invention which includes a glass Substrate and a mul
`tiple layer low-E coating System coated on a Surface of the
`glass Substrate;
`0009 FIG. 2 is a graph of %. Transmission and transmit
`ted a, b Values for glass articles containing a low-E
`coating of this invention compared against other coatings
`not within the Scope of this invention; and
`0010 FIG. 3 is a graph showing the concentration, in
`atomic percent (at. %), of constituents of a SiAION,
`coating on a Si Substrate according to Example III, Test
`Sample 3 below versus the depth of the coating in Ang
`Stroms (A).
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`0011. Accompanying FIG. 1 depicts in a schematic fash
`ion one particularly preferred embodiment of the present
`invention. In this regard, the multiple layer low-E coating of
`the present invention will necessarily be applied onto a glass
`substrate 10 which is, in and of itself, highly conventional.
`Specifically, the glass substrate 10 is most preferably made
`by a conventional float process and is thus colloquially
`known as “float glass'. Typical thicknesses of Such float
`glass may be from about 2 mm to about 6 mm, but other
`glass thicknesses may be employed for purposes of the
`present invention. The composition of the glass forming the
`Substrate 10 is not critical, but typically the glass Substrate
`will be formed of one of the Soda-lime-Silica types of glass
`well known to those in this art.
`0012. The process and apparatus used to form the various
`layers comprising the low-Ecoating of the present invention
`may be a conventional multi-chamber (multi-target) Sputter
`coating System Such as that disclosed generally in U.S. Pat.
`No. 5,344,718 (the entire content of which is incorporated
`expressly herein by reference). One particularly preferred
`Sputter-coating System is commercially available from
`Airco, Inc. AS is well known, the glass Substrate 10 is
`advanced Sequentially through the contiguous chambers or
`Zones which have respective atmospheres to form Sputter
`coating layers of desired constituency and thickness.
`0013 AS depicted in FIG. 1, one particularly preferred
`low-E coating may be formed of the following layerS and
`layer thicknesses (identified sequentially from adjacent the
`glass substrate 10 toward the outside):
`
`Layer Constituent
`(u)
`transparent dielectric
`(a)
`silicon nitride (Si3N)
`(b)
`nitrided nichrome (NiCrM)
`(c)
`silver (Ag)"
`
`Thickness
`Range (A)
`about 100-200
`about 25-200
`about 2-40
`about 100-200
`
`Thickness
`Preferred (A)
`about 125
`about 125
`about 10
`about 145
`
`Page 5 of 8
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`

`

`US 2001/0041252A1
`
`Nov. 15, 2001
`
`-continued
`
`Thickness
`Thickness.
`Layer Constituent
`Range (A)
`Preferred (A)
`(d)
`nitrided nichrome (NiCrn)
`about 2-40
`about 20
`(e)
`silicon nitride (Si3N)
`about 350-600
`about 480
`'Silver is sputter-coated onto the glass substrate surface in a nitrogen-con
`taining atmosphere.
`
`0014) The undercoat layer (u) in FIG. 1 is selected so it
`has an index of refraction at 550 nm wavelength of about 2.5
`to about 2.6, and preferably about 2.52. Preferably, the
`undercoat layer (u) includes at least one transparent dielec
`tric selected from TiO, BiO, PbO and mixtures thereof.
`TiO, is especially preferred.
`0.015 The low-E coated glass article embodying the
`present invention will exhibit a relatively high light trans
`missivity (i.e., greater than about 72%) and will have
`acceptable a* and b* transmission of between about -2.0 to
`-4.0 (preferably about -3.0) for a transmission, and
`between about -0.5 to about 1.5 (preferably about 0.5) for
`b* transmission.
`0016. According to the present invention, nitrogen gas is
`used in the Sputtering Zone to form the NiCr layer and the Ag
`layer. Most preferably, the gas will be a mixture of nitrogen
`and argon, wherein less than about 25% of the gas is
`nitrogen and greater than about 75% of the gas is argon.
`Most preferably, nitrogen is present in the Sputter Zones
`using nichrome (i.e., 80% Ni/20% Cr) and silver targets to
`form the nitrided nichrome and Silver layers, respectively, in
`an amount between about 5% to about 25%. A ratio of argon
`to nitrogen of 85:15 is especially preferred in each Such
`Sputtering Zone.
`0017 Advantageously, oxygen is employed in the sput
`tering Zone during the formation of layer (a) So as to form
`a silicon oxynitride. Most preferably, the silicon oxynitride
`layer (a) is sputter-coated in a gaseous atmosphere com
`prised of nitrogen, oxygen and argon, wherein at least
`between about 5% to about 50%, most preferably about
`10%, of the gas is oxygen. A particularly preferred atmo
`sphere for Sputter-coating the Silicon oxynitride layer (a) is
`about 30% N, about 10% O and about 60% Ar.
`0.018. According to the present invention, the rate at
`which oxygen gas is incorporated into a Silicon nitride layer
`(a) during formation can be varied So as to obtain a Silicon
`Oxynitride layer having an oxygen gradient. By the term
`"oxygen gradient' is meant that the concentration of oxygen
`(atomic percent (at. %)) decreases from one location in a
`Silicon oxynitride layer to another location at a different
`depth in that same layer. If present, the oxygen gradient is
`most preferably Such that the greater amount of oxygen
`concentration is nearer the bottom of the layer (i.e., towards
`the glass Substrate) with the lesser amount of oxygen con
`centration being nearer the top of the layer (i.e., away from
`the glass Substrate). In terms of the decrease in oxygen
`concentration, the oxygen gradient layer may throughout the
`layer depth be Substantially linear or non-linear. Alterna
`tively (or additionally), the layer may include decreasing
`oxygen concentrations that are both linear and non-linear at
`Selected regions thereof throughout the layer depth.
`0019. The oxygen gradient layer may be obtained by
`introducing a portion of oxygen gas at the leading Section of
`
`the coater Zone where the deposition of Silicon nitride
`occurs. While not wishing to be bound by any particular
`theory, it is believed that the oxygen gradient layer is in part
`responsible for improved mechanical durability in Sputter
`coated glass products which are Subsequently heat treated.
`0020. The oxygen gradient that may be present in the
`coatings of the present invention is most typically embodied
`in a decrease in the oxygen concentration, expressed in
`atomic percent (at. %), which is present in the layer per unit
`depth of the layer, expressed in Angstroms (A), of about 0.6
`at.%/A or less. Oxygen gradients of between about 0.1 to
`about 0.6 at. %/A are thus embodied in the present inven
`tion. According to Some especially preferred embodiments,
`an oxygen gradient of between about 0.15 to about 0.25 at.
`%/A is obtained.
`0021 AS one specific example, a plot of atomic percent
`vs. depth was generated for Test Sample 3 of Example III
`below and is presented as accompanying FIG. 3. AS shown
`therein, the oxygen concentration decreases from between
`about 35 to about 40 at. % at a depth of about 375 A in the
`coating, to a relatively constant value of about 5 at. 76 at a
`layer depth of about 200 A.
`0022. Those skilled in this art will recognize that a wide
`variety of oxygen gradient layerS may be produced depend
`ing on the particular proceSS techniques employed. For
`example, variations in the line Speed of the glass Substrate
`through the Sputter coater and/or variations in the quantity of
`oxygen introduced at the leading edge of the coater Zone
`may be employed So as to produce a Silicon oxynitride layer
`having the desired oxygen gradient.
`0023. A greater understanding of this invention will be
`achieved by careful consideration of the following non
`limiting Examples.
`
`EXAMPLES
`
`0024 Example I
`0025) A low emissivity coating comprised of layers (u)
`through (e) as identified generally in FIG. 1 was applied
`onto a float glass Substrate using a multi-chamber Sputter
`coater (Airco, Inc.) at a line speed of 175 in/min under the
`following conditions:
`
`Layer (u):
`
`Layer (a):
`
`Layer (b):
`
`TiO2 - 6 Dual C-MAG cathodes (12 Ti metal targets)
`Three cathodes are in the first coat Zone (CZ1) and three
`are in the second Coat Zone (CZ2).
`Each coat Zone is run identically - DC Reactive sputtering
`Pressure = 3.5 mTorr
`Gas Ratio (60% O2/40% Ar)
`Total gas flow = 1850 (sccm)
`Power - ~80 kW per target
`SixNy - 3 Dual C-MAG cathodes (6 Plasma Sprayed Si/Al
`targets ~8% AI)
`Bi-Polar Pulsed DC power
`Pressure = 2.5 mTorr
`Gas Ratio (30% N2, 70% Ar)
`Total gas flow = 1425 sccm
`Power - ~5 kW per target
`NiCrM - 1 Planar cathode (80% Ni/20% Cr)
`DC Sputtered
`Pressure = 2.5 mTorr
`Gas Ratio (85% Ar, 15% N.)
`Total gas flow = 1125 sccm
`Power - ~4.0 kW per target (Range 3 to 5 kW)
`
`Page 6 of 8
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`

`

`US 2001/0041252A1
`
`Nov. 15, 2001
`
`Layer (c):
`
`Layer (d)
`
`Layer (e):
`
`-continued
`
`Ag - 1 Planar Cathode (100% Silver)
`DC Sputtered
`Pressure = 2.5 mTorr
`Gas Ratio (85% Ar, 15% N.)
`Total gas flow = 1125 sccm
`Power - ~7.75 kW per target (Range 5 to 9 kW,
`RS = 3 to 10 Ohm per square)
`NiCrM - 1 Planar cathode (80% Ni/20% Cr)
`DC Sputtered
`Pressure = 2.5 mTorr
`Gas Ratio (85% Ar, 15% N.)
`Total gas flow = 1125 sccm
`Power - ~4.0 kW per target (Range 3 to 5 kW)
`SixNy - 3 Dual C-MAG cathodes (6 Plasma Sprayed Si/Al
`targets ~8% AI)
`Bi-Polar Pulsed DC power
`Pressure = 2.5 mTorr
`Gas Ratio (60% N2, 40% Ar)
`Total gas flow = 2050 sccm
`Power - ~28 kW per target
`
`0026. Example II
`0027 Example I was repeated except that layer (a) was
`Sputter-coated using the following conditions to form a
`Silicon oxynitride:
`
`Layer (a):
`
`SiOxNy - 3 Dual C-MAG cathodes (6 Plasma Sprayed
`Si/Al targets ~8% AI)
`Bi-Polar Pulsed DC power
`Pressure = 2.5 mTorr
`Gas Ratio (30% N2, 10% O2, 60% Ar)
`Total gas flow = 1425 sccm
`Power - ~7 kW per target
`
`0028. Example III
`0029 Test Samples obtained from Example I (identified
`as Sample Nos. 4 and 5) and Example II (identified as
`Sample Nos. 6 and 7) were tested for light transmissivity and
`transmitted a, b Values. In comparison, Test Sample Nos.
`1-2 and 8-9 having non-nitrided NiCr and Ag layers (all
`other layers in the Stack being Substantially the same as
`Sample Nos. 4-7) were also tested for light transmissivity
`and a, b Values. Comparative Test Sample No. 3 was
`identical to Test Sample Nos. 1-2, except that a layer of
`silicon oxynitride was interposed between the TiO, and NiCr
`layers. The data appear in accompanying FIG. 2.
`0.030. As will be observed, the transmissivity of Samples
`4-7 was acceptably high (i.e., greater than about 72%) with
`low a transmission Values. In this regard, it was noted that,
`even though the b Value of Sample Nos. 4–7 increased as
`compared to Test Sample Nos. 1-3 and 8-9, the greater
`transmissivity of the former made the b Value less critical.
`Thus, it was noted that when the transmission is high, the
`“blue” color hue is less sensitive.
`0.031
`While the invention has been described in connec
`tion 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.
`
`What is claimed is:
`1. A Surface-coated glass article comprised of a glass
`Substrate and a multiple layer coating on a Surface of the
`glass Substrate, wherein Said coating includes a layer of a
`transparent dielectric material adjacent the Surface of the
`glass Substrate, respective layers nichrome and Silver each
`Sputter-coated onto the glass Substrate in a nitrogen-contain
`ing atmosphere.
`2. The Surface-coated glass article of claim 1, wherein the
`coating further includes a layer of Silicon oxynitride inter
`posed between Said layer of dielectric material and Said layer
`of nichrome.
`3. The Surface-coated glass article of claim 2, wherein
`Said Silicon oxynitride layer includes an oxygen gradient
`layer.
`4. The Surface-coated glass article of claim 3, wherein
`Said oxygen gradient layer has an oxygen concentration
`which decreases between about 0.1 to about 0.6 at. %/A
`from one location in the layer to another location at a
`different depth in the layer.
`5. The Surface-coated glass article of claim 4, wherein
`Said oxygen gradient layer has an oxygen concentration
`which decreases between about 0.15 to about 0.25 at. %/A.
`6. The Surface-coated glass article of claim 3, 4 or 5,
`wherein Said oxygen gradient layer has an oxygen concen
`tration which is greater at a location nearer to the glass
`Substrate.
`7. The Surface-coated glass article of claim 1, wherein the
`dielectric material is at least one Selected from the group
`consisting of TiO, BiO, PbO and mixtures thereof.
`8. The Surface-coated glass article as in claim 1, wherein
`the coating further includes, from the layer of Silver out
`Wardly, a Second layer of nitrided nichrome, and an outer
`layer of SiN.
`9. The Surface-coated glass article as in claim 1, wherein
`the coating further includes a layer of SiN interposed
`between Said dielectric material and Said layer of nichrome.
`10. A Surface-coated glass article comprised of a glass
`Substrate and a multiple layer coating comprising the fol
`lowing layerS formed on a Surface of the glass Substrate,
`from the surface outwardly:
`(1) a layer of transparent dielectric material;
`(2) an inner layer of SiN. or a layer of Silicon oxynitride;
`(3) a first layer of nitrided nichrome;
`(4) a layer of Silver which is Sputter-coated onto the glass
`Substrate in a nitrogen-containing atmosphere;
`(5) a Second layer of nitrided nichrome; and
`(6) an outer layer of SiN.
`11. The Surface-coated glass article of claim 10, wherein
`the dielectric material is at least one Selected from the group
`consisting of TiO, BiO, PbO and mixtures thereof.
`12. The Surface-coated glass article of claim 1 or 10,
`having a light transmission of at least about 72%.
`13. The Surface-coated glass article of claim 12, having
`transmitted a, b Values of between about -2.0 to -4.0, and
`between about -0.5 to about 1.5, respectively.
`14. The Surface-coated glass article of claim 1 or 10,
`wherein the layerS have the following thicknesses in Ang
`StromS.
`(1) between about 100-200;
`(2) between about 25-200;
`
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`US 2001/0041252A1
`
`Nov. 15, 2001
`
`(3) between about 2-40;
`(4) between about 100-200;
`(5) between about 2-40; and
`(6) between about 350-600.
`15. A method of making a Surface-coated glass article
`comprising Sputter-coating on a Surface of a glass Substrate
`a multiple layer coating comprised of a layer of a transparent
`dielectric material adjacent the Surface of the glass Substrate,
`and respective layers of nichrome and Silver which are
`Sputter-coated onto the glass Substrate in a nitrogen-contain
`ing atmosphere.
`16. The method of claim 15, wherein said layers of
`nichrome and Silver are each formed by Sputter-coating in a
`gaseous atmosphere comprised of nitrogen and argon,
`wherein the nitrogen is present in the atmosphere in an
`amount less than about 25%.
`17. The method of claim 16, wherein nitrogen is present
`in an amount between about 15% to about 25%.
`18. The method of claim 16, wherein the ratio of argon to
`nitrogen is about 85:15.
`19. The method of claim 16, which further comprises
`forming a Silicon oxynitride layer between Said layer of
`dielectric material and Said layer of nichrome.
`20. The method of claim 15, wherein said layer of silicon
`Oxynitride is formed by Sputter-coating in a gaseous atmo
`Sphere comprised of nitrogen, oxygen and argon, wherein
`
`the oxygen is present in the atmosphere in an amount
`between about 5 to about 50%.
`21. The method of claim 20, wherein oxygen is present in
`the atmosphere in an amount of about 10%.
`22. The method of claim 21, wherein the atmosphere
`comprises about 30% nitrogen, about 10% oxygen and about
`60% argon.
`23. The method of any one of claims 15-22, wherein the
`Sputter-coating of the Silicon oxynitride layer includes using
`an aluminum-containing Silicon target.
`24. The method of claim 23, wherein the target includes
`about 8% by weight aluminum.
`25. The method of claim 19 or 20, comprising forming the
`Silicon oxynitride layer So as to include an oxygen gradient
`layer therein.
`26. The method of claim 25, wherein Said oxygen gradient
`layer is formed So as to exhibit an oxygen concentration
`which decreases between about 0.1 to about 0.6 at. %/A
`from one location in the layer to another location at a
`different depth in the layer.
`27. The method of claim 26, wherein said oxygen gradient
`layer has an oxygen concentration which decreases between
`about 0.15 to about 0.25 at. %/A.
`28. The Surface-coated glass article of claim 25, wherein
`Said oxygen gradient layer has an oxygen concentration
`which is greater at a location nearer to the glass Substrate.
`
`k
`
`k
`
`k
`
`k
`
`k
`
`Page 8 of 8
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