WO2014158796A1

WO2014158796A1 - Plasma deposition method

Info

Publication number: WO2014158796A1
Application number: PCT/US2014/020215
Authority: WO
Inventors: Syed Salman ASAD; Pierre Descamps; Vincent Kaiser; Patrick Leempoel
Original assignee: Dow Corning Corporation
Priority date: 2013-03-14
Filing date: 2014-03-04
Publication date: 2014-10-02
Also published as: TW201447023A

Abstract

A method of plasma deposition of a coating on a substrate using a non-thermal equilibrium atmospheric pressure plasma generated with a plasma reactor device spaced apart from the substrate by a gap, the method comprising: generating a turbulent luminous plasma jet at atmospheric pressure within a luminous zone of a chamber defined by a dielectric housing having an outlet, the generating being done in such a way that the turbulent luminous plasma jet diffuses laterally to create a region of diffused luminous plasma within the luminous zone of the chamber and the turbulent aspect of the turbulent luminous plasma jet is insensitive to, and not a function of, the existence and size of the dielectric housing and the gap between dielectric housing and the substrate; contacting the turbulent luminous plasma jet with an atomized precursor material to give coating-useful products within the luminous zone of the chamber; allowing the coating-useful products including a diffused plasma, but not the turbulent luminous plasma jet, to flow from the luminous zone to the outlet of the dielectric housing, and then out of the outlet of the dielectric housing to give released coating-useful products disposed outside the dielectric housing and spaced apart from the turbulent luminous plasma jet, and contacting the released coating-useful products to the substrate so as to form the coating on the substrate. A manufactured article comprising a coated substrate prepared by the method.

Description

PLASMA DEPOSITION METHOD

[0001] This invention comprises a plasma deposition method and manufactured articles prepared therewith

[0002] Plasma deposition methods of coating substrates using luminous plasma in direct contact with the substrates are known. Such methods use a luminous laminar or turbulent plasma jet in a housing in such a way that the plasma jet propagates to the outlet of the housing and beyond, where the luminous plasma directly contacts the substrate. The laminar plasma jet drives activated species downward onto a narrow area of substrate.

[0003] The method of WO 2012/010299 A1 uses, inter alia, a dielectric housing having an outlet spaced apart from a substrate by a gap. The method, among other steps, positions the substrate adjacent to the outlet of the dielectric housing so that the surface of the substrate is in contact with the plasma. Also, the method controls the flow rate of process gas and the gap between the outlet of the dielectric housing and the substrate so that the process gas has a turbulent flow regime within the dielectric housing.

[0004] In an attempt to overcome problems of direct plasma methods, a method with the substrate being positioned remotely from the excitation medium was developed in US 7,968,154 B2. The remote substrate excitation medium method of US 7,968,154 B2 contacts coating-forming material to a laterally generated excitation medium.

[0005] The inventors discovered problems with prior art methods. For example regarding the laminar plasma jet method, we found that moving the laminar plasma jet away from the substrate, or moving the substrate away from the laminar plasma jet, would disadvantageously allow surrounding atmosphere or vacuum to perturb the flow dynamics of the laminar plasma jet and lead to inhomogeneous coatings. E.g., inhomogeneous coatings would have undesirably high total thickness variation (TTV), non-uniform coverage of the surface of the substrate being coated, or both. In addition, moving the laminar plasma jet away from the substrate creates a relatively large unconfined space between the outlet of the plasma reactor device and the substrate and disadvantageously allows scattering of coating-useful species due to bouyant and non-bouyant flow thereof in all directions before reaching the substrate. This scattering would result in a loss of reactive species and decrease efficiency of the laminar plasma jet method. Further, we found that creating turbulent plasma by controlling the flow rate of process gas and the gap between the dielectric housing and the substrate is undesirably sensitive to small changes in the size of the gap. These small changes can abruptly switch the plasma from a turbulent flow regime to a laminar flow regime and undesirably give inhomogeneous coatings. [0006] Our efforts to solve some of the problems with prior art methods led us to an improved method of plasma deposition of a coating on a substrate where the coating may have one or more improved characteristics. We believe that our technical solutions to the problems we identified are not disclosed, taught, or suggested by the cited art.

BRIEF SUMMARY OF THE INVENTION

[0007] This invention comprises a plasma deposition method wherein a luminous plasma is not in direct contact with a substrate, and manufactured articles prepared therewith. Embodiments of the invention include:

[0008] A method of plasma deposition of a coating on a substrate using a non-thermal equilibrium atmospheric pressure plasma generated with a plasma reactor device spaced apart from the substrate by a gap, the method comprising: generating a turbulent luminous plasma jet at atmospheric pressure within a luminous zone of a chamber defined by a dielectric housing having an outlet, the generating being done in such a way that the turbulent luminous plasma jet diffuses laterally to create a region of diffused luminous plasma within the luminous zone of the chamber and the turbulent aspect of the turbulent luminous plasma jet is insensitive to the existence and size of the dielectric housing and the gap between dielectric housing and the substrate; contacting the turbulent luminous plasma jet and diffused luminous plasma with an atomized precursor material to give coating-useful products within the luminous zone of the chamber, wherein the coating-useful products comprise reactive precursor species and precursor fragments; allowing the coating-useful products including a diffused plasma, but not the turbulent luminous plasma jet, to flow from the luminous zone to the outlet of the dielectric housing, and then out of the outlet of the dielectric housing to give released coating-useful products disposed outside the dielectric housing and spaced apart from the turbulent luminous plasma jet; and contacting the released coating-useful products to the substrate so as to form the coating on the substrate, wherein the coating is derived from the released coating-useful products. The existence of the turbulent aspect of the turbulent luminous plasma jet is insensitive to, and not a function of, the existence and size of the dielectric housing and the gap between dielectric housing and the substrate. The turbulent luminous plasma jet and does not directly contact the substrate, or even reach the outlet of the dielectric housing.

[0009] A manufactured article comprising a coated substrate prepared by the method.

[0010] The plasma reactor device is constructed to enable the method. The method is useful for preparing the coated substrate of the manufactured articles. The manufactured articles are useful in a variety of applications. The foregoing embodiments may have other uses and applications, including those unrelated to coating uses and applications.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Embodiments of the invention and certain advantages may be illustrated and described by referring to the accompanying drawings.

[0012] Figure (Fig.) 1 is a cutaway view of an embodiment of the plasma reactor device that may be employed in some embodiments of the method and a substrate.

[0013] Fig. 2a is a photograph of a coated substrate.

[0014] Fig. 2b is a drawing of a serpentine deposition path of the plasma reactor device used to coat the substrate in Fig. 2a.

[0015] Fig.3 is a photograph showing a perspective view of a circular substrate partially coated by an embodiment of the method.

DETAILED DESCRIPTION OF THE INVENTION

[0016] The Brief Summary and Abstract are incorporated here by reference. The invention embodiments include the method and manufactured article described above. The invention also includes a method of plasma deposition of a coating on a substrate using a non-thermal equilibrium atmospheric pressure plasma, wherein the method uses a dielectric housing that is spaced apart from the substrate by a gap, the dielectric housing defining a chamber and having proximal and distal ends spaced apart from each other via the chamber, the proximal end of the dielectric housing defining a process gas inlet and precursor material inlet and the distal end of the dielectric housing defining an outlet, wherein the inlets are spaced apart from each other and from the outlet, wherein the chamber has a luminous zone adjacent the inlets of the dielectric housing and, optionally, a non-luminous zone adjacent the outlet of the dielectric housing, wherein the inlets are in fluid communication with the outlet of the dielectric housing sequentially via the luminous zone and then non-luminous zone, when present, of the chamber, and wherein the dielectric housing functions to guide flow of reactive species from the plasma to the substrate, the method comprising: generating a turbulent luminous plasma jet at atmospheric pressure within the luminous zone of the chamber in such a way that the turbulent luminous plasma jet diffuses laterally to create a region of diffused luminous plasma within the luminous zone of the chamber and the turbulent aspect of the turbulent luminous plasma jet is insensitive to the existence and size of the dielectric housing and the gap between dielectric housing and the substrate; contacting the turbulent luminous plasma jet and diffused luminous plasma with an atomized precursor material to give coating-useful products within the luminous zone of the chamber, wherein the coating-useful products comprise reactive precursor species and precursor fragments; allowing the coating-useful products including a diffused plasma, but not the turbulent luminous plasma jet, to flow from the luminous zone to the outlet of the dielectric housing, and then out of the outlet of the dielectric housing to give released coating-useful products disposed outside the dielectric housing and spaced apart from the turbulent luminous plasma jet; and contacting the released coating-useful products to the substrate so as to form the coating on the substrate, wherein the coating is derived from the released coating-useful products.

[0017] The method comprises the step of generating a turbulent luminous plasma jet at atmospheric pressure within the luminous zone of the chamber in such a way that the turbulent luminous plasma jet diffuses laterally to create a region of diffused luminous plasma within the luminous zone of the chamber and the turbulent aspect of the turbulent luminous plasma jet is insensitive to the existence and size of the dielectric housing and the gap between dielectric housing and the substrate. An inventive aspect of this invention is that the plasma jet would be turbulent even in the absence of the dielectric housing. The method does not employ the dielectric housing to create a turbulent plasma regime. The dielectric housing does not function in the method to create turbulence, but primarily guides flow of material to the substrate. The dielectric housing may have additional functions in the method as long as those additional functions do not include creating a turbulent plasma regime. Further, the turbulence of the plasma jet would not be affected by changing the size of the dielectric housing, changing the size of the gap, or removing the dielectric housing. That is, the turbulent aspect of the turbulent plasma jet is insensitive to, and not a function of, the existence and size of the dielectric housing and the gap between dielectric housing and the substrate. This means the turbulent aspect of the turbulent plasma jet would remain if the dielectric housing were removed and, alternatively, at all sizes of the gap if the dielectric housing is present. The invention encompasses any suitable generating method of achieving this result. An example of such a suitable generating method comprises generating the turbulent luminous plasma jet within (and confined within) the luminous zone using the following steps: applying a radio frequency voltage to an electrode positioned within the process gas inlet of and spaced apart from the dielectric housing to give an active electrode, wherein the radio frequency voltage is effective for generating a plasma and the process gas inlet has an actual hydraulic diameter, D^act; flowing a process gas having a kinematic viscosity, vg, to the process gas inlet at a flow rate, F, through the process gas inlet past the active electrode to and then out of the outlet of the dielectric housing, wherein kinematic viscosity, Vg, of the process gas is less than the kinematic viscosity, v|_|_e, of helium, wherein kinematic viscosities, v, are determined at 25 degrees Celsius; and wherein the D^act is greater than or equal to a calculated hydraulic diameter, D^calc, wherein D^calc = 4^*F/(-rr^*v^*Re), wherein^*indicates multiplication, / indicates division, F and each v are as defined above, and Re is a Reynolds number equal to or greater than 1 ,000; thereby generating the turbulent luminous plasma jet at atmospheric pressure within the luminous zone of the chamber.

[0018] The turbulent luminous plasma jet diffuses laterally to create the region of diffused luminous plasma within the luminous zone of the chamber. Typically this diffusion begins at a distance from the process gas inlet of about 10 times the actual hydraulic diameter, D^act, of the process gas inlet. The diffused luminous plasma is formed by a natural lateral spreading or scattering of the turbulent luminous plasma outward from the turbulent luminous plasma jet in a direction approximately perpendicular to the axis of the jet. For example, when the turbulent luminous plasma jet is disposed in a vertical downward y- direction, the diffused luminous plasma is formed by a natural outward spreading or scattering of the turbulent luminous plasma laterally in an approximately x-direction. The luminosity of the diffused luminous plasma naturally decreases as the diffused plasma moves closer to the outlet of the dielectric housing until, if the dielectric housing is long enough, eventually the diffused plasma becomes the diffused non-luminous plasma prior to reaching the outlet of the dielectric housing. The optional portion of the chamber wherein the diffused plasma becomes non-luminous is referred to herein as the non-luminous zone of the chamber.

[0019] The method also includes the step of contacting the turbulent luminous plasma jet and diffused luminous plasma with an atomized precursor material to give coating-useful products within the luminous zone of the chamber, wherein the coating-useful products comprise reactive precursor species and precursor fragments. The contacting may be performed by flowing or injecting the atomized precursor material into the luminous zone of the chamber, wherein the contacting occurs.

[0020] The method also includes the step of allowing the coating-useful products including a diffused plasma, but not the turbulent luminous plasma jet, to flow from the luminous zone to the outlet of the dielectric housing, and then out of the outlet of the dielectric housing to give released coating-useful products disposed outside the dielectric housing and spaced apart from the turbulent luminous plasma jet. The turbulent luminous plasma jet may be kept spaced apart from the outlet of the dielectric housing by using a dielectric housing having a sufficient length such that the turbulent luminous plasma jet spreads laterally or scatters to form the diffused luminous plasma within and before reaching the outlet of the dielectric housing. The diffused plasma may be luminous, alternatively luminous in the luminous zone and non-luminous in the non-luminous zone of the chamber. When the diffused plasma leaving the outlet is non-luminous, the allowing step may comprise using a dielectric housing of sufficient length so as to allow formation of the non-luminous zone and allowing the coating-useful products to flow from the luminous zone of the chamber to the non-luminous zone of the chamber, at which non-luminous zone the diffused luminous plasma has become a diffused non-luminous plasma. Then, allowing the coating-useful products including the diffused non-luminous plasma to flow from the non-luminous zone of the chamber to the outlet, and then out of the outlet of the dielectric housing to give released coating-useful products disposed outside the dielectric housing and spaced apart from the turbulent luminous plasma jet. The non-luminous zone lacks the turbulent luminous plasma jet and diffused luminous plasma. In some embodiments of the method, the non-luminous zone is absent from the chamber. In other embodiments of the method, the non-luminous zone is present in the chamber. The absence or presence of the non-luminous zone in the chamber is a function of the length of the chamber from the process gas inlet(s) to the outlet of the dielectric housing. The distance of the non-luminous zone from the process gas inlets of the dielectric housing is a function of where the diffused luminous plasma has lost its luminosity and become non-luminous, and not the other way around.

[0021] Alternatively when the diffused plasma is luminous, this allowing step may comprise allowing the coating-useful products including the diffused luminous plasma, but not the turbulent luminous plasma jet, to flow from the luminous zone directly to the outlet of the dielectric housing, and then out of the outlet of the dielectric housing to give released coating-useful products including the diffused luminous plasma disposed outside the dielectric housing and spaced apart from the turbulent luminous plasma jet.

[0022] The method also includes the step of contacting the released coating-useful products to the substrate so as to form the coating on the substrate, wherein the coating is derived from the released coating-useful products. The contacting may be performed in by allowing the released coating-useful products along to fall incident on and physically contact a coating-ready surface of the substrate. The released coating-useful products may comprise the diffused luminous plasma, alternatively the diffused non-luminous plasma. [0023] The turbulent luminous plasma jet does not directly contact the substrate, or even reach the outlet of the dielectric housing. In some embodiments the diffused luminous plasma may not directly contact the substrate, or even reach the outlet of the dielectric housing. Alternatively in other embodiments as described herein, the diffused luminous plasma, but not the turbulent luminous plasma jet, may directly contact the substrate before all of the diffused luminous plasma can become non-luminous. The embodiments of the method wherein the diffused luminous plasma directly contacts the substrate may be achieved by shortening the length of the dielectric housing (e.g., dielectric conduit) such that the optional non-luminous zone of the chamber does not have a chance to form during the method, and some of the diffused luminous plasma exits the outlet of the dielectric conduit. The gap between the dielectric housing and the substrate typically is independent of the length of the chamber defined in dielectric housing, and more typically the gap is the same irrespective of the length of the chamber defined therein.

[0024] Shortly after start-up and/or at steady-state conditions, the turbulent luminous plasma jet and diffused luminous plasma, and any diffused non-luminous plasma co-exist simultaneously during the foregoing steps of the method. The plasma is characterizable as being luminous in the luminous zone of the chamber and non-luminous in the non-luminous zone, when present, of the chamber during the foregoing steps of the method.

[0025] When present the non-luminous zone of the chamber is generally characterizable as having a diffused non-luminous plasma disposed therein during the method, wherein the diffused non-luminous plasma is not visible to the unaided human eye. The luminous zone of the chamber is generally characterizable as having luminous plasma disposed therein during the method, wherein the luminous plasma is visible to the unaided human eye. For ease of comparisons and record keeping, the luminosity and non-luminosity of the plasma may be characterized using a digital detection method described later. For example, the luminosity of the plasma may be detectable by the detection method, and the non-luminosity of the plasma is not detectable by the detection method.

[0026] The luminous zone of the chamber may be readily divided into two regions: a luminous plasma jet region ("zone 1 ") and the diffused luminous plasma region ("zone 2"). The luminous plasma jet region is disposed immediately adjacent the inlets (e.g., the process gas inlets and atomized precursor material inlet) of the dielectric housing and the diffused luminous plasma region is disposed between the luminous plasma jet region and either the outlet of the dielectric housing or the non-luminous zone ("zone 3") , when present, of the chamber. The luminous plasma jet region may be characterizable as having a linear and well-defined luminous plasma jet, typically of cylindrical shape. The diffused luminous plasma region may be characterizable as having the diffused luminous plasma, which is indistinct in form or shape. Each of the luminous plasma jet and diffused luminous plasma regions independently has a length (vertical distance) of from 1 to 10 times the actual hydraulic diameter, D^act, of the largest diameter process gas inlet. The length of the luminous plasma jet region is independent of the flow rate, F, of the process gas entering the process gas inlet from which the luminous plasma jet exited. Determining the precise boundary between the luminous plasma jet region and the diffused luminous plasma region is not important to the invention method. Similarly, determining the precise boundary between the luminous zone and the non-luminous zone, when present, is not important to the invention method. During the method the luminous zone and any non-luminous zone in the chamber may be readily appreciated with the unaided human eye, alternatively with the later described detection method.

[0027] The method may comprise feeding the process gas used to generate the turbulent plasma in a downward y-direction towards the substrate disposed under the plasma reactor device, as opposed to in a horizontal or lateral x-direction parallel to a substrate. The method is based on an inventive technical solution to a problem discovered when overcoming drawbacks of using bouyant plasma jets such as those produced with downwardly-fed helium process gas at atmospheric pressure. The respective drawbacks include scattering of coating-useful products and perturbing the overall flow dynamics of the coating-useful products near the substrate. The drawbacks gave low deposition rates and/or inhomogeneous coatings. The method beneficially enables production of a wall jet of the coating-useful products within the gap between the dielectric housing and the substrate when using a downwardly-fed process gas. The method beneficially decouples flow dynamics of the downwardly fed process gas from flow dynamics of the coating-useful products at the gap. The invention technical solution is not achievable, disclosed, taught or suggested by the cited art.

[0028] As used herein, "may" confers a choice, not an imperative. Optionally" means is absent, alternatively is present. "Contacting" means bringing into physical contact. Operative contact" comprises functionally effective touching, e.g., as for modifying, coating, adhering, sealing, or filling. The operative contact may be direct physical touching, alternatively indirect touching. All U.S. patent application publications and patents referenced herein, or a portion thereof if only the portion is referenced, are hereby incorporated herein by reference to the extent that incorporated subject matter does not conflict with the present description, which would control in any such conflict. All "wt%" (weight percent) are, unless otherwise noted, based on total weight of all ingredients used to make the composition, which adds up to 100 wt%. Any Markush group comprising a genus and subgenus therein includes the subgenus in the genus, e.g., in Markush group "R is hydrocarbyl or alkenyl," R may be alkenyl, alternatively R may be hydrocarbyl, which includes, among other subgenuses, alkenyl. A "non-invention" aspect does not mean prior art aspect; any non- invention aspect independently may, alternatively may not be prior art. All viscosities, including kinematic viscosities, and density are conducted at 25 degrees Celsius (° C) and 101 kilopascals (kPa) unless otherwise noted. Terms of the general format "organopolysiloxane" and terms of the general format "polyorganosiloxane" may be used interchangeably herein. The term "substantially the same" means at least 90%, alternatively at least 95%, alternatively at least 98%, but less than 100% identical. The "x-direction" and "y-direction" respectively refer to horizontal and vertical axes of a Cartesian coordinate system. When referring to the turbulent luminous plasma jet produced in the method, that term and the terms plasma jet, turbulent plasma, turbulent plasma jet, and luminous plasma jet may be used interchangeably herein.

[0029] The method is illustrated below with reference to an embodiment wherein the diffused plasma contacting the substrate is the diffused non-luminous plasma. An example of a device suitable for use in the method is shown in Fig. 1 . The device of Fig. 1 will be used to illustrate, but not limit, the types of devices that are suitable for use in the method. In the method, the device of Fig. 1 feeds the process gas used to generate the plasma in a downward y-direction towards the substrate.

[0030] In the Figure(s), like numerals indicate like parts throughout. Like parts, however, may be given different numerals for convenience of distinguishing between them in the following description.

[0031] Fig. 1 shows the cutaway view of an embodiment of a suitable plasma reactor device and a substrate. In Fig. 1 , plasma reactor device 1 comprises the following elements and features: electrodes 1 1 and 12, chamber 13, dielectric conduit 14, outlet 15, process gas inlets 16 and 17, dielectric injector body 19, atomizer 21 , precursor material inlet 22, nebulizer outlet 23, and metal plate 28. Device 1 optionally may further comprise dielectric support 27. Device 1 is constructed, and variants of would be constructed, to enable the method and may be used in some embodiments of the method. Also shown for convenience in Fig. 1 is a substrate 25 and a gap 30 between dielectric conduit 14 and substrate 25. [0032] Referring again to Fig. 1 , device 1 comprises dielectric injector body 19, dielectric conduit 14, and electrodes 1 1 and 12. Dielectric injector body 19 defines the process gas inlets 16 and 17. Electrodes 1 1 and 12 are centered in process gas inlets 16 and 17, respectively. Electrodes 1 1 and 12 and process gas inlets 16 and 17 are dimensioned such that each of the process gas inlets 16 and 17 independently has an actual hydraulic diameter, D^act. Dielectric injector body 19 also defines atomizer 21 . Atomizer 21 has precursor material inlet 22 and nebulizer outlet 23. Dielectric conduit 14 has proximal and distal ends (not indicated) spaced apart from each other. Dielectric conduit 14 may be cylindrical, alternatively box-shaped, alternatively ellipsoidal, alternatively another geometric shape, alternatively a non-geometric shape. In Fig. 1 , dielectric conduit 14 is cylindrical. The proximal end of dielectric conduit 14 is adjacent to, and in sealing operative contact with, dielectric injector body 19 and the distal end of dielectric conduit 14 defines outlet 15. Together dielectric injector body 19 and dielectric conduit 14 comprise a dielectric housing that defines chamber 13, which is an enclosed volumetric space except for process gas inlets 16 and 17 and outlet 15. Metal plate 28 is disposed perpendicular to and spaced apart from outlet 15 of dielectric conduit 14. Metal plate 28 may be grounded, alternatively ungrounded. Fig. 1 shows the optional dielectric support 27, which is disposed above and substantially parallel to metal plate 28. Fig. 1 also shows substrate 25 disposed on dielectric support 27 such that substrate 25 is spaced apart from outlet 15 of dielectric conduit 14 by gap 30. Gap 30 is a space in fluid communication with atmosphere (e.g., air) surrounding device 1 (i.e., exterior to device 1 ) and contents of chamber 13.

[0033] Referring again to Fig. 1 , during the method chamber 13 is designed to have a luminous zone (not indicated) adjacent process gas inlets 16 and 17 of dielectric injector body 19 and a non-luminous zone (not indicated) adjacent the outlet 15 of the dielectric conduit 14, wherein process gas inlets 16 and 17, and atomizer 21 , are in fluid communication with outlet 15 of dielectric conduit 14 sequentially via the luminous zone and then non-luminous zone of chamber 13. That is, process gas inlets 16 and 17, and atomizer 21 are in sequential fluid communication with the luminous plasma jet region of the luminous zone, the diffused plasma region of the luminous zone, the non-luminous zone, and outlet 15, all of chamber 13. The fluid communication through chamber 13 typically is unimpeded due to a lack of intervening physical structures in chamber 13. Alternatively, the device (1 ) may further comprise a physical structure, such as a baffle, disposed within chamber 13, which physical structures may alter course of, but not prevent, the fluid communication through chamber 13. The luminous zone of chamber 13 may be the upper 5 to 95 volume percent (vol%) portion (not indicated) of chamber 13 and inversely the non-luminous zone of chamber 13 may be the lower 95 to 5 vol% portion (not indicated) of chamber 13. During the method the luminous zone contains the turbulent luminous plasma, which is spaced apart from outlet 15 of dielectric conduit 14 by the non-luminous zone of chamber 13.

[0034] During the method a process gas is fed through process gas inlets 16 and 17 and past electrodes 1 1 and 12, respectively, into chamber 13, all of plasma reactor device 1 . A precursor material is fed through atomizer 21 from precursor material inlet 22 to nebulizer outlet 23, and on into chamber 13. Atomizer 21 atomizes the precursor material (not shown) to give an atomized form of the precursor material (not shown) in the luminous plasma jet region of the luminous zone of chamber 13. Alternatively, atomizer 21 may be absent from of plasma reactor device 1 , and instead the precursor material may be incorporated as a gas into the flow of precursor gas entering via precursor gas inlets 16 and/or 17. Electrodes 1 1 and 12 are energized such that a turbulent luminous plasma jet (not shown) is generated at atmospheric pressure within the luminous plasma jet region of the luminous zone of chamber 13 in such a way that the turbulent aspect of the turbulent luminous plasma jet is insensitive to, and not a function of, the existence and size of dielectric conduit 14 and gap 30 between dielectric conduit 14 and substrate 25. The luminous plasma (turbulent luminous plasma jet and diffused luminous plasma) is contacted with the atomized precursor material to give coating-useful products (not shown) within the luminous zone of chamber 13. The coating-useful products including a diffused plasma, but not the turbulent luminous plasma jet, are allowed to flow from the luminous zone to the outlet 15 of dielectric conduit 14, and then out of outlet 15 of dielectric conduit 14 to give released coating-useful products including diffused non-luminous plasma disposed outside the dielectric housing and spaced apart from the turbulent plasma. The diffused plasma may be the diffused luminous plasma, but for the present illustration the diffused plasma is the diffused non-luminous plasma. The coating-useful products flow to the non-luminous zone (not indicated) of chamber 13, at which non-luminous zone the diffused luminous plasma has become a diffused non- luminous plasma. The coating-useful products then flow from the non-luminous zone of chamber 13 to outlet 15, and out of outlet 15 of dielectric conduit 14 to give the released coating-useful products. The released coating-useful products including the diffused non- luminous plasma are contacted to the substrate so as to form the coating on the substrate, wherein the coating is derived from the released coating-useful products. The turbulent luminous plasma jet (not shown) does not directly contact substrate 25, or even reach outlet 15 of dielectric conduit 14. Only plasma in the form of the diffused non-luminous plasma (not shown) exits outlet 15 of dielectric conduit 14 and contacts substrate 25.

[0035] Referring again to Fig. 1 , the step of generating the turbulent plasma within the luminous zone (not indicated) may comprise applying a radio frequency (1 kilohertz (kHz) to 300 Gigahertz (GHz)) voltage to electrodes 1 1 and 12 positioned within process gas inlets

16 and 17 of the dielectric injector body 19 portion of the dielectric housing to make electrodes 1 1 and 12 active. The radio frequency voltage is effective for generating a plasma. The process gas has a kinematic viscosity, vg, and is flowed to each of the process gas inlets 16 and 17 at independent flow rates, F. The kinematic viscosity, vg, of the process gas is less than the kinematic viscosity, v|_|_e, of helium. The D^act is greater than or equal to a calculated hydraulic diameter, D^ca'^c, wherein D^ca'^c = 4 * F/(n * v * Re), wherein * indicates multiplication, / indicates division, F and each v are as defined above, and Re is a

Reynolds number equal to or greater than 1 ,000 (i.e., Re > 1 .000 x 10³). For example, Re may be > 1 .000 x 10³; alternatively > 1 .5 x 10³; alternatively > 2.0 x 10³; alternatively > 2.5 x 10³. Re may have any upper limit. A practical upper limit for Re may be 5 x 10³; alternatively 4 x 10³; alternatively 3 x 10³.

[0036] During use of plasma reactor device 1 , turbulent plasma jets form and exit inlet 16 and 17 into the luminous zone of chamber 13. That is, the turbulent aspect of the turbulent plasma is insensitive to, and not a function of, the existence and size of dielectric conduit 14 and gap 30 between dielectric conduit 14 and substrate 25. The plasma jet would be naturally turbulent even in absence of dielectric conduit 14, which is primarily used in the method to physically guide flow of materials such as plasma and coating-useful products, including reactive species, from the plasma to the substrate. With Re > 1 ,000, designing process gas inlets 16 and 17 to independently have actual hydraulic diameter, D^act, that is greater than or equal to calculated hydraulic diameter, D^calc, based on Re, and using a process gas having kinematic viscosity, vg, less than the kinematic viscosity, v|_|_e, of helium, the turbulent plasma jets are generated at atmospheric pressure and are confined in the plasma jet region of the luminous zone of chamber 13. For convenience, this is referred to herein as feature (a).

[0037] Referring again to feature (a), during the method the turbulent plasma jets have improved mixing and contacting interactions with the injected atomized precursor material because, once out of process gas inlets 16 and 17 and into the luminous zone of chamber 13, the turbulent luminous plasma jets spread laterally in the luminous zone of chamber 13 rather than project downwardly towards outlet 15 of chamber 13. That is, the flow rate, F, of the process gas no longer increases the projection of plasma jet down the dielectric conduit

14, but rather the turbulent luminous plasma jets are localized to and remain in the luminous plasma jet region of the luminous zone of the chamber 13. Advantageously, dielectric conduit 14 guides and directs flow of the coating-useful products and any unreacted process gas down to outlet 15 without the coating-useful products and unreacted process gas getting spread or lost in the lateral direction, i.e., direction perpendicular to the axis of dielectric conduit 14, as would happen if dielectric conduit 14 had not been used.

[0038] Referring again to feature (a), during the method the kinematic viscosity, Vg, of the process gas, the process gas flow rate, F, and the geometry of the dielectric conduit 14 at its outlet 15 enable the part of the flow of coating-useful products that are exiting outlet 15 near the wall (not indicated) of dielectric conduit 14 and adjacent gap 30 between the distal end (not indicated) of dielectric conduit 14 and substrate (25) to satisfy the condition for having a non bouyant jet of coating-useful products at outlet 15. This condition is satisfied when using a process gas that has a density that is equal to or greater than density of atmosphere surrounding dielectric conduit 14. For example, the condition is satisfied when using Argon as process gas and air as the surrounding atmosphere wherein density of argon is greater than that of air at their respective temperatures during the method.

[0039] Under the conditions used in the method, the length, L^c, of chamber 13 along its axis, i.e., from process gas inlets 16 and 17 in dielectric injector body 19 to outlet 15 of dielectric conduit 14 is long enough distance to enable having the turbulent luminous plasma separated from the non-luminous zone therein, but not so long distance that all of the reactive species created in the luminous zone have time to deactivate by the time the resulting coating-useful reaction products exit outlet 15 of dielectric conduit 14 and contact substrate 25. This condition allows process gas activated species and precursor molecules or fragments to further interact either in the non-luminous zone of chamber 13 or at the surface of substrate 25. Further, the dielectric conduit 14 primarily functions to guide and direct the coating-useful products through the luminous and non-luminous zones to the substrate, thereby preventing scattering of the coating-useful products before they reach the substrate. For convenience, this is referred to herein as feature (b). A typical length, L^c, of chambers such as 13 is from 8 millimeters (mm) to 400 mm , alternatively from 8 to 90 mm, alternatively from 90 to 200 mm. A typical average diameter of chamber 13, i.e., inner diameter of dielectric conduit 14, is from 8 to 500 mm (e.g., 18 mm). The length, L^c, may be greater than, equal to, or less than the inner diameter of the dielectric conduit. For example, when there are few process gas inlets in the dielectric injector body (e.g., such as only 16 and 17 in dielectric injector body 19 in Fig. 1 ), the length, L^c, may be greater than the inner diameter of dielectric conduit such as 14. When there are many process gas inlets in the dielectric injector body (e.g., 10 or 20 process gas inlets, not shown), the length, L^c, may be less than the inner diameter of dielectric conduit (not shown). For example, the length of the dielectric housing may be from 8 to 400 millimeters; the inner diameter of the dielectric housing may be from 8 to 500 millimeters, and optionally the length is greater than the inner diameter of the dielectric housing. The length, L^c, helps avoid, or minimize, any plasma- induced damage to the plasma-incident surface (upper surface, not indicated) of substrate 25 that would otherwise result if the substrate would have been contacted with plasma. In addition, the length L^c allows the mixing and formation of turbulent luminous plasma jet and diffused luminous plasma and prevents each turbulent luminous plasma jet and diffused luminous plasma from being in direct contact with the substrate. Only the diffused non- luminous plasma is in direct contact with the substrate. Length L^c prevents the coating- useful products from having a localized deposition on areas of substrate 25 that would be positioned underneath process gas inlets 16 and 17, thereby minimizing or avoiding an undesirable non-homogeneous deposition of the coating on substrate 25. That is, the turbulent luminous plasma ((luminous plasma jet region) may not propagate down the entire length, L^c, of chamber 13 of device conduit 14.

[0040] There is also a possibility to satisfy the condition for non-bouyant jet of coating-useful materials at the outlet (e.g., 15) of the dielectric housing when using a process gas of density equal to or lower than density of air if the process gas flow rate, F, and gap 30 are selected in such a way that the Froude number, Fr, for the plasma jet is maximized. The Froude number, Fr, is the ratio between Inertia force to bouyant force according to the following mathematical formula: Fr = U₀ ² / (g ^* D^{Frcl *} (p₀-p_a)/po ) > 1 , wherein ^* and / are as defined above; U₀ is the velocity of the coating-useful products, g is the constant of gravity, p_Q is density of process gas, p_g is density of surrounding atmosphere (air), wherein D^Frcl is hydraulic diameter of a cylindrical-shaped gap (e.g. 30) circumscribed by a cylindrical dielectric conduit (e.g., 14) above the substrate (e.g., 25), wherein D^Frcl = 2 ^* gap 30 and U₀ equals the flow rate of the coating-useful products divided by the surface area of the gap (e.g., 30) equal to product of the (distance between dielectric conduit (e.g., 14) and substrate (e.g., 25)) times (circumference of cylindrical dielectric conduit (e.g., 14)). For convenience, this is referred to herein as feature (c).

[0041] Without being bound by theory the method achieves certain benefits by identifying and combining for the first time features (a) to (c) in a single process. For example, feature (a) results in a turbulent plasma jet spreading in the x-direction (i.e., horizontally in the luminous zone (not indicated) of chamber 13), thereby increasing collisions and interactions between the turbulent plasma and the atomized precursor material injected into the luminous zone from atomizer 21 , all while ensuring the turbulent luminous plasma jets stay in the luminous plasma jet region of the luminous zone during the method steps of generating, contacting, allowing and contacting. Feature (b) combined with feature (a) results in flow dynamics in the luminous and non-luminous zones of the chamber (e.g., 13) being decoupled from flow dynamics at the outlet (e.g., 15) of the chamber (e.g., 13), which ensures that the turbulent plasma regime in the luminous zone will not change if the gap (e.g., 30) between the outlet (e.g., 15) of the chamber (e.g., 13) and the substrate (e.g., 25) would be increased. It may be desirable and beneficial to increase the gap (e.g., 30) to allow the coating-useful products to spread out further in the x-direction over the substrate, thereby increasing the area of the substrate being coated in given pass of the plasma reactor device over the substrate, or a single pass of the substrate under the plasma reactor device (e.g., 1 ). Before the present invention, increasing the gap (e.g., 30) would perturb plasma jet. Feature (b) also ensures the active species in the coating-useful products (e.g., process gas activated species, precursor molecules, and fragments of precursor molecules) will still be present when the latter are forming the coating on the substrate. Feature (c) relates to inertia of the flow of gas of coating-useful products that is exiting chamber (e.g., 13) via outlet (e.g., 15), and results in the flow of coating-useful products being in the form of a wall jet through the gap (e.g., 30) between the dielectric conduit (e.g., 14) and the substrate (e.g., 25). Feature (c) ensures that the flow of the coating-useful products is not perturbed, or minimally perturbed by any movement of outside atmosphere (e.g., air current). The method using the combination of features (a) to (c) provides the turbulent plasma as a stable jet that is not influenced, or only minimally influenced, by atmosphere (e.g., air) surrounding the plasma reactor device (e.g., 1 ) during the coating formation, thereby increasing homogeneity of, decreasing powder formation in, and decreasing total thickness variation (TTV) of the coating that is deposited on the substrate. [0042] A benefit of the method is that the resulting coating on the substrate has reduced TTV. The method also increases symmetrical character of the coating as viewed across the area of the coating that is positioned directly under outlet 15 of chamber 13. By comparison with a non-invention method, if a laminar plasma jet is used instead of the present turbulent plasma, the thickness of the non-invention coating on the substrate that is positioned directly in the center under the laminar plasma jet propagating down to the substrate would be greatest, and the thickness would decrease radially outward from the area of the substrate area directly hit by the jet. Thus, the TTV of the non-invention coating would be greater and the non-invention coating would be less symmetrical than the TTV and symmetrical nature of the invention coating. The advantage of reduced TTV is illustrated in Fig. 2a. In Fig. 2a, a circular substrate is shown after being coated by the method using argon as process gas. Visual observation shows the coating to be homogeneous and uniform across the substrate. The coating shown in Fig. 2a was applied to the substrate using the serpentine deposition path of the plasma reactor device shown in Fig. 2b.

[0043] An additional benefit is the method increases the deposition rate of the coating-useful products that form the coating on the substrate compared to a non-invention method that uses a laminar plasma jet or that uses a plasma that is not turbulent or where the coating- useful products are not guided or directed towards the substrate. Also, the invention coating is formed not just directly under the outlet 15 of chamber 13, but extends well beyond area of substrate under where dielectric conduit 14 is positioned. This is because the wall jet geometry created by the gap (e.g., 30) between the distal end of the dielectric housing (e.g., distal end of 14) and the substrate forces all the active components of the coating-useful products that are exiting the outlet (e.g., 15) of the dielectric chamber (e.g., 13) to travel parallel to the surface of the substrate, increasing the length of time for their coating interaction with the substrate. Thus, the released coating-useful products may diffuse through gap 30 onto areas of substrate 25 that are positioned under surrounding atmosphere such as air. Thus, the size of the coated area for a given diameter of dielectric conduit 14 is increased by the method. Also, the deposition efficiency consequently is increased in the method, wherein the deposition efficiency is defined as the ratio between the mass of the film deposited on the substrate to the mass of the precursor fed to the dielectric chamber.

[0044] This advantage of extending the area of coating beyond the area of the substrate that is directly under the dielectric conduit 14 is illustrated in Fig. 3. Fig. 3 shows a perspective photographic view of a circular substrate partially coated by an embodiment of the method. In Fig. 3, a circle 32 corresponds to the inner diameter of the dielectric conduit 14 (Fig. 1 ). The deposition pattern shown in Fig. 3 is symmetrical with respect to the circular shape of 14, and the deposition extends up to 30 mm away from the area of substrate positioned directly underneath outlet 15 of dielectric conduit 14. The area in circle 32 that has a radius < inner diameter of dielectric conduit 14 has a brown color and corresponds to a thinner but homogeneous film thickness. Also, a blue color 34 area extending symmetrically over all the wafer surface from chamber exit corresponds to a thicker deposition, showing that deposition takes place far apart from dielectric chamber exit and is not influenced by the surrounding environment (air). Because the symmetry of the static deposition pattern, the move of dielectric conduit 14 over a substrate 25 following the serpentine travel pattern shown in Fig. 2b leads to the deposition of a film perfectly homogenous in thickness (Fig. 2a).

[0045] The process gas may have a kinematic viscosity, vg, less than the kinematic viscosity, v|_|_e, of helium. That is, the process gas may have a kinematic viscosity, vg, equal to or less than 1 .17^*10^-4 square meters per second (m²/s). The kinematic viscosity, Vg , of the process gas may be < 1 .00^*10^~4 m²/s, alternatively < 8^*10^"5 m²/s, alternatively < 6^*10^"5 m²/s, alternatively < 4^*10^"^ m²/s, alternatively < 2^*10^"^ m²/s. The kinematic viscosity, Vg, of the process gas may be > 1 ^*10^~6 m²/s, alternatively > 5^*10^~6 m²/s, alternatively > 1 ^*10^~5 m²/s. The process gas may be a gas of argon, nitrogen, or a mixture of argon and nitrogen. Argon has a kinematic viscosity, vg, equal to 1 .3416^*10^~5 m²/s at 25° C and 101 kPa. The process gas may contain de minimus amount of helium (e.g., < 5 wt%, alternatively < 2 wt%, alternatively < 1 wt%. Alternatively the process gas lacks helium (0.0 wt% He). The process gas may be any gas or mixture of gases that satisfies the conditions (e.g., features (a) to (c)) or the kinematic viscosity relationship of Vg and V|_|_e described above.

[0046] The process gas may have a density, d, that is greater than the density, d, of helium at 25 ° C and 101 kPa.

[0047] The process gas may be flowed at the flow rate, F, to each process gas inlet, wherein independently for each process gas inlet F is from 1 ^*10^~5 cubic meters per second (m³/s) to 1 ^*10^~3 m³/s. Within this range, the flow rate, F, of the process gas to the process gas inlet may be > 2^*10^"^ m³/s, alternatively > 4^*10^"^ m³/s, alternatively > 8^*10^"^ m³/s; and/or < 8 0^"4 m³/s, alternatively < 6 0^"4 m³/s, alternatively < 4 0^"4 m³/s. The flow of the process gas may be pulsed, alternatively continuous.

[0048] The precursor material may be a single substance, a mixture of two or more substances, or a sequentially fed train of two or more different substances. The sequentially fed train of two or more different substances may enable the method to produce a multi- layered coating on the substrate 25.

[0049] The precursor material is any substance that may be atomized and ionized by the turbulent plasma and guided or directed through chamber 13 so as to form a coating on substrate 25. For example, the precursor material may be a polymerizable precursor material. The precursor material may be solid, liquid, or gaseous or vaporous, or a mixture of any two or more thereof. The precursor material may be inorganic or organic. Suitable organic precursor materials are carboxylates, methacrylates, acrylates, styrenes, methacrylonitriles, alkenes and dienes, for example methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, and other alkyl methacrylates, and the corresponding acrylates, including organofunctional methacrylates and acrylates, including poly(ethylene glycol) acrylates and methacrylates, glycidyl methacrylate, trimethoxysilyl propyl methacrylate, allyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, dialkylaminoalkyl methacrylates, and fluoroalkyl (meth)acrylates, methacrylic acid, acrylic acid, fumaric acid and esters, itaconic acid (and esters), maleic anhydride, styrene, a-methylstyrene, halogenated alkenes, for example, vinyl halides, such as vinyl chlorides and vinyl fluorides, and fluorinated alkenes, for example perfluoroalkenes, acrylonitrile, methacrylonitrile, ethylene, propylene, allyl amine, vinylidene halides, butadienes, acrylamide, such as N-isopropylacrylamide, methacrylamide, epoxy compounds, for example glycidoxypropyltrimethoxysilane, glycidol, styrene oxide, butadiene monoxide, ethylene glycol diglycidylether, glycidyl methacrylate, bisphenol A diglycidylether (and its oligomers), vinylcyclohexene oxide, conducting polymers such as pyrrole and thiophene and their derivatives, and phosphorus-containing compounds, for example dimethylallylphosphonate. The precursor material may also comprise acryl-functional organosiloxanes and/or silanes.

[0050] Suitable inorganic precursor materials may be metals, metal oxides, or silicon containing materials. Organometallic compounds may also be suitable precursor materials. Such organometallic compounds include metal alkoxides such as titanates, tin alkoxides, zirconates and alkoxides of germanium and erbium. The silicon-containing precursor materials may be siloxane-based. Suitable silicon-containing precursor materials include silanes (for example, silane, alkylsilanes, alkylhalosilanes, alkoxysilanes) and linear (for example, polydimethylsiloxane or polyhydrogenmethylsiloxane) and cyclic siloxanes (for example, octamethylcyclotetrasiloxane), including organo-functional linear and cyclic siloxanes (for example, Si-H containing, halo-functional, and haloalkyl-functional linear and cyclic siloxanes, e.g. tetramethylcyclotetrasiloxane and tri(nonafluorobutyl)trimethylcyclotrisiloxane). A mixture of different silicon-containing precursor materials may be used, for example to tailor the physical properties of the substrate coating for a specified need (e.g. thermal properties, optical properties, such as refractive index, and viscoelastic properties.

[0051] The method converts the process gas and precursor materials into coating-useful products, which comprise reactive precursor species and precursor fragments and any process gas.

[0052] The substrate (e.g., 25 in Fig. 1 ) may be any material suitable for receiving the coating via plasma deposition at atmospheric pressure according to the method. A range of functional coatings may be deposited onto numerous substrates using different precursor materials to prepare the coating-useful products. These coatings are grafted to the substrate and may retain the functional chemistry of the molecules of the precursor material. The substrate may be silicon such as a silicon wafer. The method may form a coating on the silicon wafer for preparing the silicon wafer for use as a photovoltaic cell. In the method the substrate may be moved relative to the outlet (e.g., 25) of the plasma reactor device (e.g., 1 ) so as to continuously coat the substrate.

[0053] The method may coat the substrate having any configuration, including two- dimensional surfaces such as major surfaces of sheet-like substrates and complex shapes such as tubing, bottles, piping, caps, packaging materials, containers, closures, boxes, cartons, pouches, blister packs, molded plastic parts and laminates, electronics equipment, optical components, medical devices, walls, flooring, powders, particles, medical implants, needles, gaskets, seals, profiles, hoses, electronic and diagnostic components, household articles including kitchen, bathroom and cookware, office furniture and laboratory ware. Hollow substrates such as the tubing or bottles may be coated on inside surfaces, outside surfaces, or both. Electronics equipment that may be coated includes textile and fabric based electronics printed circuit boards, displays including flexible displays, and electronic components such as resistors, diodes, capacitors, transistors, light emitting diodes (LEDs), organic LEDs, laser diodes, integrated circuits (ICs), IC dies, IC chips, memory devices, logic devices, connectors, keyboards, semiconductor substrates, photovoltaic cells, wafers for preparing photovoltaic cells, and fuel cells. Optical components include lenses, contact lenses and other optical substrates. The manufactured article may comprise a coated substrate produced by coating any one of the foregoing substrates according to the method.

[0054] Examples of coatings that may be formed by the method are coatings that function for surface activation, anti-microbial, friction reduction (lubricant), bio-compatible, corrosion resistance, oleophobic, hydrophilic, hydrophobic, barrier, self cleaning, trapped actives and print adhesion coatings.

[0055] The method may apply active materials on the substrate where the active materials may be trapped on the substrate. The term "active material(s)" means one or more materials that perform one or more specific functions when present in a certain environment but do not undergo chemical bond forming reactions within the present plasma environment. The active material is clearly discriminated from the term "reactive"; a reactive material or chemical species is intended to mean a species which undergoes chemical bond forming reactions within a plasma environment. The active material may of course be capable of undergoing a reaction after the coating process. Examples of suitable active materials include antimicrobials (for example, quaternary ammonium and silver based), enzymes, proteins, DNA/RNA, pharmaceutical materials, UV screen, anti-oxidant, flame retardant, cosmetic, therapeutic or diagnostic materials antibiotics, anti-bacterials, anti-fungals, cosmetics, cleansers, growth factors, aloe, and vitamins, fragrances & flavours; agrochemicals (pheromones, pesticides, herbicides), dyestuffs and pigments, for example photochromic dyestuffs and pigments and catalysts. The chemical nature of the active material(s) used in the present invention is/ are generally not critical. They can comprise any solid or liquid material which can be bound in the composition and where appropriate subsequently released at a desired rate

[0056] Plasma used herein can in general be any type of non-equilibrium atmospheric pressure plasma. The plasma may be a non-local thermal equilibrium atmospheric pressure plasma discharge including dielectric barrier discharge and diffuse dielectric barrier discharge such as glow discharge plasma.

[0057] The plasma reactor device (e.g., 1 in Fig. 1 ) may have 1 , 2, or more than 2 electrodes (e.g., 1 1 and 12). Even with 1 electrode, the device still gives the turbulent plasma. The presence of a high potential electrode generates a sufficiently strong electric field in the vicinity of the process gas such as Ar(g) or N2(g) to give rise to a plasma ionisation process and form the turbulent plasma. The electrode may be a bare metal electrode such as a tungsten electrode. The electrode may incorporate a radioactive element to facilitate ionization of process gas. The electrode may come to a sharp point to facilitate process gas ionization. The electrode may be solid or hollow. The process gas may be blown past the exterior of the solid electrode or through the interior and/or past the exterior of the hollow electrode.

[0058] The plasma reactor device (e.g., 1 in Fig. 1 ) may have outlet (e.g., 15) that may be adjusted by swapping in and out different dimensioned dielectric conduits (e.g., 14). Different sized outlets may enable coating different sized substrates more efficiently.

[0059] The atomizer (e.g., 21 in Fig. 1 ) may be any such device suitable for atomizing the precursor material. The atomizer may use the process gas to atomize the precursor material. The atomizer can for example be a pneumatic nebuliser, particularly a parallel path nebuliser such as that sold by Burgener Research Inc. of Mississauga, Ontario, Canada, or that described in US Patent 6634572; an ultrasonic atomizer such as ultrasonic nozzles from Sono-Tek Corporation, Milton, New York, USA; electrospray techniques. The atomizer may be combined with the electrode so that the atomizer also functions as the electrode.

[0060] The power supply (not shown) to the electrode or electrodes (e.g., 1 1 and 12 in Fig. 1 ) is a radio frequency power supply that is in the range 1 kHz to 300GHz. The method may use a very low frequency (VLF) 3kHz - 30 kHz band, although the low frequency (LF) 30kHz - 300 kHz range can also be used successfully. One suitable power supply is the Haiden Laboratories Inc. The frequency of the unit is also variable (1 - 100 kHz) to match the plasma system.

[0061] Dielectric elements of plasma reactor devices may be composed of any material that is a nonconductor of direct electric current and suitable for contact with the turbulent plasma. Examples of such materials are organic polymers such as polyamides, polyolefins such as polypropylene, polyperfluoroolefins such as polytetrafluoroethylene; soda-lime glasses such as quartz, alumina, and composites of such materials including fiberglass-reinforced organic polymers. Examples of suitable plasma reactor devices are those described in US 2009/0142514 A1 that may be readily adapted for using in the method.

[0062] This invention solves some of the problems discovered for prior art plasma deposition methods. For example, the method forms a coating on the substrate wherein the coating has reduced total thickness variation (TTV) compared to non-invention methods. Certain aspects of this invention may independently solve additional problems and/or have other advantages.

[0063] Materials used in the Comparative and/or Invention Examples: [0064] The invention is further illustrated by, and each composition/method may be any combinations of features and limitations of, the non-limiting examples thereof that follow. The concentrations of ingredients in the compositions/formulations of the examples are determined from the weights of ingredients added unless noted otherwise.

[0065] Plasma luminosity/non-luminosity detection method: record a sample image of plasma using a NIKON COOLPIX D5000 digital camera set at a shutter aperture of 5.6 millimeters and shutter speed of 1 /16 per second when the plasma is disposed in a black box. Store the resulting sample image in a computer, and process it with ImageJ image processing software. The sample image may be displayed or printed as gray-scale or color images. Use the ImageJ software to determine color density values at a wavelength of from 380 to 760 nanometers. Compare the color density values of the sample image to color density values obtained at same wavelengths for a reference "black" image taken with the plasma turned off.

[0066] Example (Ex.) 1 : using the plasma reactor device 1 of Fig. 1 , Reynolds number Re > 1 ,000; Argon gas as process gas entering process gas inlets 16 and 17 at flow rate, F, equal to 2.0 liters per minute (L/min) ; the calculated hydraulic diameter, D^calc, for process gas inlets 16 and 17 is 1 .6 mm, and thus the actual hydraulic diameter, D^act, for each of process gas inlets 16 and 17 is equal to or greater than 1 .6 mm.

[0067] Ex. 2: using the plasma reactor device 1 of Fig. 1 , Reynolds number Re > 1 ,000; Argon gas as process gas entering process gas inlets 16 and 17 at flow rate, F, equal to 20

L/min; the calculated hydraulic diameter, D^calc, for process gas inlets 16 and 17 is 16 mm, and thus the actual hydraulic diameter, D^act, for each of process gas inlets 16 and 17 is equal to or greater than 16 mm.

[0068] Ex. 3: using the plasma reactor device 1 of Fig. 1 , a cylindrical dielectric conduit 14 has circumference P = 56.5 mm and an inner diameter of 18 mm ; dielectric conduit 14 is positioned over substrate 25 with gap 30 of either 0.5 mm or 1 mm. The hydraulic diameter,

D^Frcl in calculating the Froude number, Fr, is gap 30 * 2, giving D^Frcl equal to 1 mm and 2 mm, respectively. The Froude number, Fr, is a function of flow of coating-useful products and process gas leaving chamber 13 expressed in L/min. The condition for Fr is better satisfied when increasing the process gas flow, F, because this results in increased inertia of coating-useful products and process gas exiting outlet 15. In case the criterion of Fr >1 is not satisfied (for instance, when F = 1 L/min and gap 30 is 1 mm), decreasing gap 30 from 1 mm to 0.5 mm allows satisfying Fr > 1 and thus the non-bouyant condition. Sample calculations are shown below in Table 1 .

[0069] Table 1 : sample calculations of Froude number, Fr.

[0070] Silicon wafer of Fig. 3 was coated using an argon process gas flow of 2.5 L/min and a gap 30 of 1 mm, satisfying the criteria of having Froude number, Fr, being significantly greater than 1 .

[0071] The below claims are incorporated by reference here as correspondingly numbered aspects except where "claim and "claims" are rewritten as "aspect" and "aspects." The invention includes such resulting numbered aspects.

Claims

What is claimed is:

1 . A method of plasma deposition of a coating on a substrate using a non-thermal equilibrium atmospheric pressure plasma generated with a plasma reactor device spaced apart from the substrate by a gap, the method comprising: generating a turbulent luminous plasma jet at atmospheric pressure within a luminous zone of a chamber defined by a dielectric housing having an outlet, the generating being done in such a way that the turbulent luminous plasma jet diffuses laterally to create a region of diffused luminous plasma within the luminous zone of the chamber and the turbulent aspect of the turbulent luminous plasma jet is insensitive to the existence and size of the dielectric housing and the gap between dielectric housing and the substrate; contacting the turbulent luminous plasma jet and diffused luminous plasma with an atomized precursor material to give coating-useful products within the luminous zone of the chamber, wherein the coating-useful products comprise reactive precursor species and precursor fragments; allowing the coating-useful products including a diffused plasma, but not the turbulent luminous plasma jet, to flow from the luminous zone to the outlet of the dielectric housing, and then out of the outlet of the dielectric housing to give released coating-useful products disposed outside the dielectric housing and spaced apart from the turbulent luminous plasma jet; and contacting the released coating-useful products to the substrate so as to form the coating on the substrate, wherein the coating is derived from the released coating-useful products.

2. A method of plasma deposition of a coating on a substrate using a non-thermal equilibrium atmospheric pressure plasma, wherein the method uses a dielectric housing that is spaced apart from the substrate by a gap, the dielectric housing defining a chamber and having proximal and distal ends spaced apart from each other via the chamber, the proximal end of the dielectric housing defining a process gas inlet and precursor material inlet and the distal end of the dielectric housing defining an outlet, wherein the inlets are spaced apart from each other and from the outlet, wherein the chamber has a luminous zone adjacent the inlets of the dielectric housing and, optionally, a non-luminous zone adjacent the outlet of the dielectric housing, wherein the inlets are in fluid communication with the outlet of the dielectric housing sequentially via the luminous zone and then non-luminous zone, when present, of the chamber, and wherein the dielectric housing functions to guide flow of active species from the plasma to the substrate, the method comprising: Generating a turbulent luminous plasma jet at atmospheric pressure within the luminous zone of the chamber in such a way that the turbulent luminous plasma jet diffuses laterally to create a region of diffused luminous plasma within the luminous zone of the chamber and the turbulent aspect of the turbulent luminous plasma jet is insensitive to the existence and size of the dielectric housing and the gap between dielectric housing and the substrate;

Contacting the turbulent plasma jet and diffused luminous plasma with an atomized precursor material to give coating-useful products within the luminous zone of the chamber, wherein the coating-useful products comprise reactive plasma species and precursor fragments;

Allowing the coating-useful products including a diffused plasma, but not the turbulent luminous plasma jet, to flow from the luminous zone to the outlet of the dielectric housing, and then out of the outlet of the dielectric housing to give released coating-useful products disposed outside the dielectric housing and spaced apart from the turbulent luminous plasma jet; and

Contacting the released coating-useful products to the substrate so as to form the coating on the substrate, wherein the coating is derived from the released coating-useful products.

3. The method of claim 2 wherein the allowing step comprises using a dielectric housing of sufficient length so as to allow formation of the non-luminous zone and allowing the coating-useful products to flow from the luminous zone of the chamber to the non-luminous zone of the chamber, at which non-luminous zone the diffused luminous plasma has become a diffused non-luminous plasma, and then allowing the coating-useful products including the diffused non-luminous plasma to flow from the non-luminous zone of the chamber to the outlet, and then out of the outlet of the dielectric housing to give released coating-useful products disposed outside the dielectric housing and spaced apart from the turbulent luminous plasma jet.

4. The method of any one of claims 1 to 3, wherein the generating the turbulent

luminous plasma jet within the luminous zone comprises:

applying a radio frequency voltage to an electrode positioned within the process gas inlet of and spaced apart from the dielectric housing to give an active electrode, wherein the radio frequency voltage is effective for generating a plasma and the process gas inlet has an actual hydraulic diameter, D^act; flowing a process gas having a kinematic viscosity, Vg, to the process gas inlet at a flow rate, F, through the process gas inlet past the active electrode to and then out of the outlet of the dielectric housing, wherein kinematic viscosity, vg, of the process gas is less than the kinematic viscosity, v|_|_e, of helium, wherein kinematic viscosities, v, are determined at 25 degrees Celsius; and

wherein the D^act is greater than or equal to a calculated hydraulic diameter,

D^ca'^c, wherein D^ca'^c = 4^*F/(n^*v^*Re), wherein^*indicates multiplication, / indicates division, F and each v are as defined above, and Re is a Reynolds number equal to or greater than 1 ,000;

thereby generating the turbulent luminous plasma jet at atmospheric pressure within the luminous zone of the chamber.

5. The method of claim 4 wherein the allowing step comprises using a dielectric housing of sufficient length so as to allow formation of the non-luminous zone and allowing the coating-useful products to flow from the luminous zone of the chamber to the non-luminous zone of the chamber, at which non-luminous zone the diffused luminous plasma has become a diffused non-luminous plasma, and then allowing the coating-useful products including the diffused non-luminous plasma to flow from the non-luminous zone of the chamber to the outlet, and then out of the outlet of the dielectric housing to give released coating-useful products disposed outside the dielectric housing and spaced apart from the turbulent luminous plasma jet and the kinematic viscosity, vg, of the process gas is equal to or less than 1 .17^*10^"4 square meters per second (m²/s).

6. The method of claim 5 wherein the process gas is a gas of argon, nitrogen, oxygen, or a mixture of argon and nitrogen.

7. The method of any one of claims 4 to 6, wherein the flow rate, F, of the process gas to the process gas inlet is from 1 ^*10^~5 cubic meters per second (m³/s) to 1 ^*10^~3 m³/s.

8. The method of any one of the preceding claims wherein the density of the process gas is greater than the density of helium.

9. The method of any one of the preceding claims wherein the dielectric housing defines at least two process gas inlets and each process gas inlet contains an electrode.

10. The method of any one of the preceding claims wherein the length of the dielectric housing is from 8 to 400 millimeters; the inner diameter of the dielectric housing is from 8 to 500 millimeters.

11 . The method of any one of the preceding claims characterizable by a static coating regime wherein a non-bouyant wall jet of the released coating-useful products form a coating on an area of the substrate greater than the surface area of the outlet of dielectric housing.

12. The method of any one of the preceding claims characterizable by a dynamic coating regime wherein the substrate and/or the plasma reactor device are moved relative to each other to form a coating on the substrate.

13. A manufactured article comprising a coated substrate prepared according to the method of any one of claims 1 to 12.