Powder Mitigation and Exhaust Management for Thin Film Deposition

Abstract

A spatial atomic layer deposition (SALD) system includes a coating head with an arrangement of channels including precursor gas channels, reactant gas channels, inert gas and exhaust channels to assist in clearing unwanted materials, such as powders, contaminants, or dust, from a target substrate at or near the deposition site. The coating head may also include surface treatment equipment, particle monitoring devices, ultrasonic vibrators, heaters, dehumidifiers, or electrostatic charge generators to assist in clearing the substrate. Various channels and auxiliary devices may be provided as modules. Surface treatment may be provided in the body of the coating head adjacent to the substrate. An exhaust flow path outside the coating head, an environmental control chamber for the coating head, and an output slit offset may also be provided.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates generally to gas control systems, and more particularly to gas control for thin film deposition. [Background technology]

[0002] Spatial atomic layer deposition (SALD) is an open-air vapor deposition technique. A coating head is typically used to deliver one or more chemical precursors, which react with other chemical precursors and / or decompose due to an external energy source (e.g., heat, laser, plasma), resulting in the deposition of a desired material on a surface. As illustrated in FIG. 1 , various gas channels may be present, including those for delivering chemical precursors, shielding gases, and energy sources, and / or exhaust channels for removing reaction products. The substrate 102 may be moved relative to the coating head 100, for example, unidirectionally or oscillatedly. With regard to gas delivery and exhaust, "i" represents inert gas, "a" represents precursor chemical gas, "b" represents reactant, and "e" represents exhaust.

[0003] The systems depicted in Figure 1 can generate powders that cause issues such as clogging. Chemical precursors can cause undesirable reactions when they mix with the atmosphere, leading to spatial and temporal nonuniformities in the deposited material or coating. Precursor and / or reactant gases can interact with each other or other gases outside of the intended context, leading to undesirable reaction products. Maintaining sufficient gas isolation to ensure that coatings can be properly deposited on substrates without being affected by ambient air and / or other gases found within the process and / or equipment is a challenge within the industry. Clogging issues, reactions with the atmosphere, insufficient gas isolation, and unexpected reaction products affect process control and can often lead to poor coating properties such as nonuniform deposition, pinhole formation, and inconsistent performance. Therefore, balancing the flow interactions between chemical precursors, shielding gases, and exhaust intensity is effective in reducing powder formation. Summary of the Invention [Means for solving the problem]

[0004] According to one aspect of the present disclosure, an SALD system includes a coating head including a precursor gas channel configured to provide a precursor gas to a substrate, a reactant gas channel positioned forward of the precursor gas channel, the reactant gas channel configured to provide the reactant gas to the substrate, and a series of inert gas channels positioned relative to the precursor gas channel and the reactant gas channel, each inert gas channel configured to provide an inert gas to the substrate and to sweep unwanted material from the substrate.

[0005] A series of inert gas channels may be positioned before or after the reactant and precursor gas channels.

[0006] A series of inert gas channels may be positioned between the reactant gas channels and the precursor gas channels.

[0007] The SALD system may further include a body provided with precursor and reactant gas channels and a module provided with a series of inert gas channels, the module being removably attachable to the body.

[0008] The SALD system may further include a surface treatment device attached to the coating head, a particulate monitoring device, an ultrasonic vibrator, a heater, a dehumidifier, an electrostatic charge generator, or a combination thereof.

[0009] The coating head may further include a surface treatment on a surface of the body of the coating head adjacent the substrate.

[0010] The surface treatment may include a layer of octadecylphosphonic acid.

[0011] The SALD system may further include a first exhaust flow path connected to an exhaust channel of the coating head adjacent to the precursor gas channel and a second exhaust flow path connected to another exhaust channel of the coating head adjacent to the reactant gas channel.

[0012] The SALD system may further include a pressure gauge positioned in the first exhaust flow path or the second exhaust flow path, and the pressure gauge may be configured to detect an obstruction in the first exhaust flow path or the second exhaust flow path.

[0013] The SALD system may further include a pump positioned in the first exhaust flow path or the second exhaust flow path and a flow rate controller connected to the pump, wherein the pump and flow rate controller may be configured to increase the flow rate of exhaust through the first exhaust flow path or the second exhaust flow path to remove the blockage.

[0014] The SALD system may further include an environmental control chamber in which the coating head is positioned. The environmental control chamber may be configured to control the temperature, pressure, and humidity of the local environment surrounding the coating head.

[0015] The end slits of the precursor or reactant gas channels may be offset from the end slits of the inert gas channels in a direction away from the substrate.

[0016] According to another aspect of the present disclosure, an SALD system includes a coating head including a precursor gas channel configured to provide a precursor gas to a substrate, a reactant gas channel positioned forward of the precursor gas channel, the reactant gas channel configured to provide the reactant gas to the substrate, and a series of exhaust channels positioned relative to the precursor gas channel and the reactant gas channel, each exhaust channel configured to draw unwanted material from the vicinity of the substrate.

[0017] A series of inert gas channels may be positioned before or after the reactant and precursor gas channels.

[0018] The SALD system may further include a body provided with precursor and reactant gas channels, and a module provided with a series of exhaust channels, the module being removably attachable to the body.

[0019] The SALD system may further include a surface treatment device attached to the coating head, a particulate monitoring device, an ultrasonic vibrator, a heater, a dehumidifier, an electrostatic charge generator, or a combination thereof.

[0020] The coating head may further include a surface treatment on a surface of the body of the coating head adjacent the substrate.

[0021] The surface treatment may include a layer of octadecylphosphonic acid.

[0022] The SALD system may further include a first exhaust flow path connected to an exhaust channel of the coating head adjacent to the precursor gas channel and a second exhaust flow path connected to another exhaust channel of the coating head adjacent to the reactant gas channel.

[0023] The SALD system may further include a pressure gauge positioned in the first exhaust flow path or the second exhaust flow path, and the pressure gauge may be configured to detect an obstruction in the first exhaust flow path or the second exhaust flow path.

[0024] The SALD system may further include a pump positioned in the first exhaust flow path or the second exhaust flow path and a flow rate controller connected to the pump, the pump and flow rate controller configured to increase the flow rate of exhaust through the first exhaust flow path or the second exhaust flow path to remove the blockage.

[0025] The SALD system may further include an environmental control chamber in which the coating head is positioned. The environmental control chamber may be configured to control the temperature, pressure, and humidity of the local environment surrounding the coating head.

[0026] The end slit of the precursor gas channel, the reactant gas channel, or the exhaust channel may be offset from the end slit of the inert gas channel in a direction away from the substrate.

[0027] According to another aspect of the present disclosure, an SALD system includes a coating head including a precursor gas channel configured to provide a precursor gas to a substrate, a reactant gas channel positioned forward of the precursor gas channel, the reactant gas channel configured to provide a reactant gas to the substrate, and a series of alternating inert gas channels and exhaust channels positioned relative to the precursor gas channel and the reactant gas channel. Each inert gas channel is configured to provide inert gas to the substrate and sweep unwanted material from the substrate. Each exhaust channel is configured to draw unwanted material from the vicinity of the substrate.

[0028] The SALD system may further include a body provided with precursor and reactant gas channels and a module provided with a series of alternating inert gas and exhaust channels, and the module may be removably attachable to the body.

[0029] The SALD system may further include a surface treatment device attached to the coating head, a particulate monitoring device, an ultrasonic vibrator, a heater, a dehumidifier, an electrostatic charge generator, or a combination thereof.

[0030] The coating head may further include a surface treatment on a surface of the body of the coating head adjacent the substrate.

[0031] The surface treatment may include a layer of octadecylphosphonic acid.

[0032] The SALD system may further include a first exhaust flow path connected to an exhaust channel of the coating head adjacent to the precursor gas channel and a second exhaust flow path connected to another exhaust channel of the coating head adjacent to the reactant gas channel.

[0033] The SALD system may further include a pressure gauge positioned in the first exhaust flow path or the second exhaust flow path, and the pressure gauge may be configured to detect an obstruction in the first exhaust flow path or the second exhaust flow path.

[0034] The SALD system may further include a pump positioned in the first exhaust flow path or the second exhaust flow path and a flow rate controller connected to the pump, wherein the pump and flow rate controller may be configured to increase the flow rate of exhaust through the first exhaust flow path or the second exhaust flow path to remove the blockage.

[0035] The SALD system may further include an environmental control chamber in which the coating head is positioned. The environmental control chamber may be configured to control the temperature, pressure, and humidity of the local environment surrounding the coating head.

[0036] The end slit of the precursor gas channel, the reactant gas channel, or the exhaust channel may be offset from the end slit of the inert gas channel in a direction away from the substrate. [Brief explanation of the drawings]

[0037] For a clearer understanding of the present disclosure, some embodiments of the present disclosure are illustrated by way of example and not limitation in the figures of the accompanying drawings.

[0038] [Figure 1] FIG. 1 is a schematic diagram of a conventional spatial atomic layer deposition (SALD) process.

[0039] [Figure 2] FIG. 2 is a schematic diagram of an additional number of inert gas channels on either side of the same coating head.

[0040] [Figure 3] FIG. 3 is a schematic illustration of an additional number of inert gas channels beside the exhaust channel surrounding the chemical precursor channel.

[0041] [Figure 4] FIG. 4 is a schematic diagram of an additional module containing an inert gas channel assembled on each side of the coating head.

[0042] [Figure 5] FIG. 5 is a schematic diagram of an additional module containing an inert gas channel on one end of the coating head.

[0043] [Figure 6] FIG. 6 is a schematic diagram of an additional module containing exhaust channels on one end of the coating head.

[0044] [Figure 7] FIG. 7 is a schematic diagram of additional modules, each containing either an inert gas channel or an exhaust channel.

[0045] [Figure 8] FIG. 8 is a schematic diagram of an additional module containing inert gas channels and exhaust channels arranged in an alternating series.

[0046] [Figure 9] FIG. 9 is a schematic diagram of a surface treater or particle monitoring device mounted on one end of a coating head.

[0047] [Figure 10] FIG. 10 is a schematic representation of a layer of coating growth inhibitor applied onto the bottom surface of a coating head.

[0048] [Figure 11] FIG. 11 is a schematic diagram of a system including the arrangement of components for generating vacuum suction (for evacuation), dynamically controlling vacuum strength, monitoring line clogging, capturing and filtering powder, and unclogging lines.

[0049] [Figure 12]FIG. 12 is a schematic diagram of a parallel bypass circuit for the powder collector and particle filter.

[0050] [Figure 13] FIG. 13 is a schematic diagram of multiple vacuum pressure gauges and on-off valves connected to individual exhaust channels in the coating head.

[0051] [Figure 14] FIG. 14 is a schematic diagram of an evacuation system that uses a mechanical vacuum pump as the vacuum source instead of using a venturi pump.

[0052] [Figure 15] FIG. 15 is a schematic diagram of an exemplary environmental control chamber configured to control the local deposition environment.

[0053] [Figure 16A] FIG. 16A is a schematic diagram of an example channel offset configured to reduce gas-gas interactions.

[0054] [Figure 16B] FIG. 16B is a schematic diagram of another example channel offset configured to reduce gas-to-gas interactions.

[0055] [Figure 17] FIG. 17 is a perspective view of an exemplary coating head that may implement any of the features and aspects discussed herein. DETAILED DESCRIPTION OF THE INVENTION

[0056] To commercialize open-air thin film deposition techniques for mass production, the process needs to be reliable and effective without significant downtime. An exhaust channel is typically connected to an exhaust system that includes one or more vacuum sources to remove reaction products. Downtime can be caused by clogging in the exhaust channel and powder buildup under the coating head. (Airborne Contamination Management)

[0057] During the deposition process, airborne particulates from the surrounding environment can contaminate the material surface. Traditional vacuum-based deposition techniques require a vacuum chamber to remove air particles and contaminants. Alternatively, clean rooms can be used to provide a well-isolated and controlled environment from contamination, but such facilities are very expensive to maintain and operate.

[0058] Conventional close-proximity SALD techniques include an air-bearing (air shock mitigation) design with a nitrogen environment between the substrate and the reactor, which can help with contaminant control. However, balancing the air-bearing for precise gap and motion control is difficult, which also limits the types of substrates that can be processed, particularly their weight and geometry.

[0059] Disclosed herein is an open-air deposition process that can operate with or without a vacuum chamber or clean room, depending on the application. The reactor has a continuous inert gas flow to purge airborne contamination and control surface quality prior to deposition. The pressure and flow rate of the exhaust as well as the inert gas flow can be actively controlled to isolate the deposition area below the coating head; by generating sufficient outflow of inert gas from the deposition area, the inflow of ambient air and contaminants is prevented. A particulate monitor can be installed to determine particulate levels near the deposition area. An air cleaner can be used to reduce dust levels. These components create an isolated environment for the coating reaction to occur on the substrate surface and keep contaminants out of the deposition area. (Substrate surface treatment and cleanliness)

[0060] Surface cleanliness is important to ensure coating quality such as consistency, uniformity, pinhole-freeness, and adhesion.

[0061] In addition to surface cleanliness, different substrate materials have different surface chemistries that affect coating properties such as, but not limited to, adhesion, morphology, density, and crystallinity.

[0062] Also disclosed herein are cleaning methods that use several sweep and evacuation steps that can be used prior to the deposition process to improve surface cleanliness.

[0063] Surface treatments such as, but not limited to, corona, plasma, and dielectric barrier discharge can be used to prime the substrate surface to improve the coating process and coating properties. It has been discovered that ozone and plasma treatments will modify the surface chemistry of some substrates (such as polyethylene) for better coating quality, improving barrier performance. Plasma ALD can be used to coat materials with difficult surface chemistries. (Precursor Gas Sequestration)

[0064] Precursor gases can be highly reactive (e.g., pyrophoric). They can react instantly when exposed to air or another reactant. Therefore, it can be essential to prevent precursor gases from unintentionally mixing and reacting with each other or with air, especially in open-air processes. During conventional atomic layer deposition (ALD) processes, precursor gases are introduced into a vacuum chamber one gas at a time to prevent them from mixing. This makes conventional ALD time-consuming and difficult to scale up.

[0065] Instead of introducing precursor gases at different times, the techniques disclosed herein introduce the gases simultaneously and spatially separate them. An inert gas flow separates the precursor gas from mixing with ambient air or nearby reactant gases. Despite the presence of inert gas flows on both sides of the precursor channel, the relative movement of the substrate and the coating head can cause air to pass through these flows. One or more inert gas flows and one or more exhaust channels can be used to sweep before and after the deposition area to reduce the amount of ambient air drawn into the deposition area. (powder reduction in coating head and channel)

[0066] Various factors, including but not limited to excess chemical precursor gas, poorly isolated precursor gas, or airborne contamination, can cause powder formation, which can accumulate in various parts of the system, including under the coating head or in the exhaust channels. Powder accumulation under the coating head can cause nonuniformities in the coating, alter the properties of the resulting coating, or partially or completely block the gas output slits. Such powder can also contaminate the surface cleanliness of the substrate and / or coating. On the other hand, powder accumulation inside one or more channels can lead to clogging, affecting exhaust effectiveness and the deposition process. Precursors can also diffuse into the bottom surface of a coating head made of plastic or similar material, causing clogging, particularly in the channel output slits, resulting in maintenance downtime for removal.

[0067] The techniques disclosed herein use various approaches to address powder buildup and maintain coating head cleanliness, such as reducing powder formation, modifying buildup areas, and using high suction.

[0068] To reduce powder formation, a gas isolation system can be used to prevent reaction of the chemical precursor with ambient air or nearby precursors.

[0069] To prevent powder formation, a film growth inhibitor can be applied to the surface of the device (e.g., the bottom surface of the coating head), which can include, for example, a self-assembled monolayer chemical that prevents the adhesion of chemical precursor molecules to the surface.

[0070] To monitor powder buildup, the pressure in the exhaust channel can be monitored. The pressure in the exhaust channel increases as clogs build up, and at a certain pressure, suction will become ineffective. Pressure and flow sensors can be integrated into the system to monitor powder buildup.

[0071] To combat powder formation, an inert gas may be introduced into the exhaust channel to divert powder formation further downstream in the exhaust system.

[0072] High suction pressure from an exhaust system may also be used to remove powder buildup from the deposition area. (Excess reactant management)

[0073] Excess chemical precursors that do not react on the substrate surface can cause unwanted chemical vapor deposition (CVD) reactions, leading to uneven coatings. They can also cause powder buildup, reducing precursor utilization. Powder buildup can clog system components, including gas channels, manifolds, and filters, rendering them ineffective.

[0074] Deposition as disclosed herein is a self-limiting process, and different sets of optimal deposition conditions for different materials are determined to reduce the amount of excess reactants. Excess reactants are removed through an exhaust channel in the coating head, which is connected to an exhaust filter and an exhaust pump and monitored by one or more flow monitors. The exhaust filter can be a replacement filter with a large capacity to collect powder and reduce buildup. The exhaust pump can be controlled to maintain the exhaust flow rate at a desired level. There can be two or more exhaust lines, and it can be possible to switch exhaust operation between lines, so that a particular exhaust line can undergo maintenance and inspection while the system remains in operation. Illustrative Embodiments

[0075] 2, an exemplary coating head 200 includes a body 202 with an arrangement 206 of gas channels configured to deposit a coating on a substrate 204. Throughout this disclosure, "i" represents an inert gas, "a" represents a precursor chemical gas, "b" represents a reactant, and "e" represents an exhaust.

[0076] The channel arrangement 206 includes a precursor gas channel 208 and additional channels in a forward direction as follows (from nearest to farthest): an exhaust channel 210-F, an inert gas channel 212-F, an exhaust channel 214-F, a reactant gas channel 216-F, an exhaust channel 218-F, and a series of inert gas channels 220-F, 222-F, and 224-F (e.g., three of them). As the substrate 204 moves forward relative to the coating head 200, at a given point on the substrate 204, the precursor gas channel 208 deposits a precursor gas, and then the excess (i.e., excess product, powder, impurities, etc.) is exhausted via the exhaust channels 210-F and 214-F with the aid of inert gas delivered by the inert gas channel 212-F before the reactant gas channel 216-F delivers the reactant gas. The residue (ie, excess product, powder, impurities, etc.) is then swept away by inert gas delivered by a series of inert gas channels 220-F, 222-F, 224-F.

[0077] The inert gas channels 220-F, 222-F, 224-F are arranged in sequence such that the substrate 204 passes through the channels in sequence. Any suitable number of inert gas channels 220-F, 222-F, 224-F may be provided, such as three, four, five, or more. The sequential introduction of inert gas to a given point on the substrate 204 and the turbulence thereby generated provides effective removal of undesired solids, gases, and other materials.

[0078] In various examples, it may be useful to provide a complementary arrangement 226 of channels extending in the rearward direction. The complementary arrangement 226 of channels is designated by the same reference number as the arrangement 206 of channels with an "R" instead of an "F." The complementary arrangement 226 of channels may function in the same manner as the arrangement 206 of channels, but in the opposite direction. Various channels in the arrangements 206, 226 may be activated and deactivated depending on the direction of movement of the substrate 204 to promote various modes of deposition.

[0079] It should be noted that throughout this disclosure, directional terms such as forward and rearward should not be considered absolute or overly limiting, but rather, these terms are relative and merely illustrate that different orientations and movements are possible.

[0080] As the substrate 204 is moved forward relative to the coating head 200, the extreme rear inert gas channels 220-R, 222-R, and 224-R provide an inert gas flow to sweep away particulates, dust, or impurities from a given point on the substrate 204 before it enters the deposition area, which begins under the precursor channel 208 and continues under channels 210-F through 218-F. Channels 212-R through 218-R, if provided, may be inactive at this point. The extreme inert gas channels 220-F, 222-F, and 224-F provide an additional inert gas flow after deposition for further sweeping.

[0081] When the substrate 204 is moved backward relative to the coating head 200, if such functionality is provided, a similar process occurs as discussed above, with the operation of the forward ("-F") and rearward ("-R") channels swapped.

[0082] In coating head 200, and in the other coating heads discussed herein, the channels are elongated channels extending along the width of the coating head and the corresponding full or partial width of substrate 204, terminating in slits through which gas is output to substrate 204. Examples of such coating heads and support systems are discussed in U.S. Published Patent Application No. US 2022 / 0243326, which is incorporated herein by reference.

[0083] 3 , an exemplary coating head 300 includes a body 302 with an arrangement 306 of gas channels configured to deposit a coating on a substrate 204. In this example, an additional inert gas flow is installed next to an exhaust channel surrounding the channel that delivers the chemical precursor gas. Powder formation can occur within the deposition area when the chemical precursor reacts with reactant gases or air in the environment before impinging on the substrate 204. The additional inert gas flow can reduce the possibility of undesired interactions of the chemical precursor gas with the reactants or environmental air, reducing powder formation and improving powder management during the deposition process.

[0084] The channel arrangement 306 includes the precursor gas channel 208 and additional channels in a forward direction as follows (from nearest to furthest): exhaust channel 210-F, inert gas channel 212-F, inert gas channel 314-F, inert gas channel 316-F, exhaust channel 318-F, reactant gas channel 320-F, exhaust channel 322-F, and inert gas channel 324-F. The series of inert gas channels 212-F, 314-F, and 316-F are positioned between the precursor gas channel 208 and the reactant gas channel 320-F.

[0085] As the substrate 204 moves forward relative to the coating head 300, at a given point on the substrate 204, the precursor gas channel 208 deposits precursor gas, and then the excess (i.e., excess product, powder, impurities, etc.) is exhausted via exhaust channel 210-F. A series of inert gas channels 212-F, 314-F, 316-F sweeps before the reactant gas channel 320-F delivers the reactant gas, assisted by exhaust channels 318-F, 322-F. A final sweep is provided by the inert gas channel 324-F.

[0086] The series of inert gas channels 212-F, 314-F, 316-F are arranged in sequence such that the substrate 204 passes through the channels in sequence. Any suitable number of inert gas channels 212-F, 314-F, 316-F may be provided, such as three, four, five, or more. The sequential introduction of inert gas to a given point on the substrate 204 and the turbulence thereby generated provides effective removal of undesired solids, gases, and other materials.

[0087] In a further example, additional exhaust channels (not shown) may be provided between the series of inert gas channels 212-F, 314-F, 316-F.

[0088] In various examples, it may be useful to provide a complementary arrangement 326 of channels extending in the rearward direction. The complementary arrangement 326 of channels is designated by the same reference number as the arrangement 306 of channels with an "R" instead of an "F." The complementary arrangement 326 of channels may function in the same manner as the arrangement 306 of channels, but in the opposite direction. Various channels in the arrangements 306, 326 may be activated and deactivated depending on the direction of movement of the substrate 204 to promote various modes of deposition.

[0089] 4, an exemplary coating head 400 includes a body 402 with a gas channel arrangement 406 configured to deposit a coating on a substrate 204. The gas channel arrangement 406 may be similar to the arrangements 206, 226 discussed above, and reference may be made to FIG. 2 and the associated description for details that will not be repeated here.

[0090] A module 408, including a body 410 with a series of inert gas channels 412, 414, 416, can be attached to the body 402 of the coating head 400 on the front side, rear side, or both sides. The module 408 allows for a variety of useful configurations of additional inert gas channels to provide sweep as needed for a particular implementation.

[0091] The modules 408 may include any suitable number of inert gas channels 412, 414, 416. Any suitable number of modules 408 may be attached to the body 402 of the coating head 400. Figure 5 shows an example coating head 500 with several modules 408 mounted on the same side of the body 402 providing the precursor, reactant, and exhaust channel arrangement 406 (details omitted from the figure for clarity). Many other examples with such modularity are also possible.

[0092] The module 408 may be removably attached to the body 402 of the coating head 400 using bolts, clamps, or similar fasteners.

[0093] 6, an exemplary coating head 600 includes a body 402 with a gas channel arrangement 406 configured to deposit a coating on a substrate 204. The gas channel arrangement 406 may be similar to the arrangements 206, 226 discussed above, and reference may be made to FIG. 2 and the associated description for details that will not be repeated here.

[0094] A module 608, including a body 610 with a series of exhaust channels 612, 614, 616, can be attached to the body 402 of the coating head 600 on the front side, rear side, or both sides. The module 608 allows for a variety of useful configurations of additional exhaust channels to provide for the evacuation of materials such as airborne particulates from the vicinity of the substrate 204, as required for a particular implementation.

[0095] The module 608 may include any suitable number of exhaust channels 612, 614, 616. Any suitable number of modules 608 may be attached to the body 402 of the coating head 600. The modules 608 may be removably attached to the body 402 using bolts, clamps, or similar fasteners.

[0096] As shown in FIG. 7 , the coating head 700 may include an inert gas module 408 having an inert gas channel combined with an exhaust module 608 having an exhaust channel. Any suitable number and configuration of modules 408, 608 may be used as required by the requirements of a particular implementation. The modules 408, 608 may be arranged in an alternating series. An inert gas may be provided to the module 408 to remove particulates from the substrate 204. A vacuum source may be provided to the module 608 to remove the removed particulates.

[0097] 8 shows another exemplary module 800 including a body 802 that includes a series of alternating inert gas channels 804 and exhaust channels 806. Like modules 408, 608, module 800 can be attached to one or both ends of the body of the coating head using bolts, clamps, or similar fasteners. Any suitable number of modules 800 can be used. Module 800 can be combined with inert gas module 408 and / or exhaust module 608.

[0098] 9, an exemplary coating head 900 includes a body 402 with a gas channel arrangement 406 configured to deposit a coating on a substrate 204. The gas channel arrangement 406 may be similar to the arrangements 206, 226 discussed above, and reference may be made to FIG. 2 and the associated description for details that will not be repeated here.

[0099] The coating head 900 further includes an auxiliary device 902 attached thereto. The auxiliary device 902 may be modular and removably attachable to the main body 402 or another module 408, 608, 800 using bolts, clamps, or similar fasteners. The auxiliary device 902 is configured to provide functionality for reducing or eliminating the presence or effects of powders and / or other undesirable materials. In various examples, the auxiliary device 902 may include a surface treatment device, a particulate monitoring device, an ultrasonic vibrator, a heater, a dehumidifier, a static charge generator, or a combination thereof.

[0100] Examples of surface treatment devices include corona treaters, plasma treaters, dielectric barrier discharge plasma sources, and ozone sources configured to prime the substrate 204 surface to improve coating quality and properties, such as coating adhesion to the substrate.

[0101] The particulate monitoring device can be configured to monitor the surface cleanliness of the substrate upon entry into and / or exit from the deposition area. Exemplary particulate monitoring devices can include devices made by Piera Systems (e.g., PEK-7100-1), which can be useful for monitoring particulates around the coating head 900 or within the wider system. Such devices allow for monitoring the amount of particles introduced at or near the deposition area during the process for quality assurance and quality control of the environment and / or deposition process.

[0102] The ultrasonic vibrator may function to dislodge powder buildup on the body 402 of the coating head 900 by vibrating at an appropriate frequency.

[0103] A heater or dehumidifier may prevent powder formation.

[0104] An electrostatic charge generator may repel the powder and prevent it from adhering to the bottom surface of the body 402 (adjacent the substrate 204) or the interior of the channels 208, 210-F through 220-R, 210-R through 220-R.

[0105] 10, an exemplary coating head 1000 includes a body 402 with a gas channel arrangement 406 configured to deposit a coating on a substrate 204. The gas channel arrangement 406 may be similar to the arrangements 206, 226 discussed above, and reference may be made to FIG. 2 and the associated description for details that will not be repeated here.

[0106] The coating head 1000 further includes a surface treatment 1002 applied to a bottom surface (the surface adjacent the substrate, when in use) of the body 402 of the coating head 1000. The surface treatment 1002 is configured to reduce or prevent adhesion of chemical precursor molecules to the bottom surface and / or to discourage powder formation on the bottom surface of 402. The same or a different surface treatment 1002 may be applied within the interior of the channels 208, 210-F through 220-R, 210-R through 220-R to reduce or prevent adhesion of chemical precursor molecules to the walls of the channels and / or to discourage powder formation within the channels 208, 210-F through 220-R, 210-R through 220-R.

[0107] The surface treatment 1002 may include a coating growth inhibitor, a low-friction material, a sacrificial layer, or a combination thereof. Examples include a coating, a deposited material, a removable plate, a removable liner, electroplating, etc. The surface treatment 1002 may be anhydrous or provide such properties to the bottom surface of the body 402. The surface treatment 1002 may be hydrophobic. Some surface treatments 1002, such as electroplating, may incorporate multiple materials, which may have other benefits besides reducing or preventing powder buildup. For example, nickel / Teflon® electroplating possesses the chemical resistance properties of nickel and Teflon®, the high sliding properties of Teflon®, as well as the insulating properties of Teflon®. Thus, the properties of the bottom surface of the coating head 1000 can be tailored by selecting a specific surface treatment 1002, such as this electroplating example.

[0108] Examples of suitable inhibitors include poly(methyl methacrylate), i.e., PMMA, octadecylphosphonic acid (ODPA), dodecanethiol (DDT), and poly(vinylpyrrolidone), i.e., PVP. One or more layers of such materials may be applied as surface treatment 1002 to the bottom surface of coating head 1000. ODPA has been tested and found to provide useful inhibition of coating growth.

[0109] 11, an exemplary exhaust system 1100 is configured to generate vacuum suction for the exhaust channels of a coating head, such as those discussed herein, and to provide line unclogging. The system 1100 outputs exhaust gases, powders, particulates, and reaction products to a central exhaust 1102, which may serve a larger manufacturing facility.

[0110] The exhaust system 1100 includes a compressed air source 1104 that supplies pressurized air to lines and ultimately to venturi pumps 1106, 1108 to create a flow rate differential to generate a vacuum.

[0111] The exhaust system 1100 includes a line (pipe, conduit, etc.) that splits into two paths (i.e., a normal-intensity exhaust path and a high-intensity exhaust path) via a two-way valve 1110, which is connected to a first Y / T fitting 1112 and a second Y / T fitting 1114. The line further splits into "A" and "B" paths that are connected to different exhaust channels within a coating head 1160, such as any of the coating heads discussed elsewhere herein. The "A" path includes a flow rate controller 1116, a check valve 1118, a Y / T fitting 1120, and a venturi pump A 1106. The "B" path includes a flow rate controller 1122, a check valve 1124, a Y / T fitting 1126, and a venturi pump 1108.

[0112] The exhaust channel in the coating head 1160 is connected to the “A” flow venturi pump 1106 via a powder collector 1130 , a vacuum pressure gauge 1132 , a particle filter 1134 , a flow meter 1136 , and a vacuum pressure gauge 1138 .

[0113] The other exhaust channel in the coating head 1160 is connected to the “B” flow path venturi pump 1108 via a particulate filter 1140 , a flow meter 1142 , and a vacuum pressure gauge 1144 .

[0114] In this example, the "A" flow path is connected to an exhaust channel adjacent to the chemical precursor gas channel in the coating head 1160. With reference to FIG. 2, for example, such exhaust channels are shown at 210-F and 210-R. The "B" flow path is connected to an exhaust channel adjacent to the reactant channel in the coating head 1160. With reference to FIG. 2, for example, such exhaust channels are shown at 214-F, 218-F, 214-R, and 218-R. Separating the exhaust into two flow paths reduces or prevents the exhausted chemical precursor gas from reacting with the exhausted reactant gas, which could occur if a single flow path were used. This can help prevent or slow powder formation and accumulation in the lines, which can cause fouling and clogging.

[0115] When the two-way valve 1110 is switched to the normal-intensity exhaust path, the exhaust pressure and flow rate generated by the "A" and "B" path venturi pumps 1106, 1108 are adjusted using the "A" and "B" path flow rate controllers 1116, 1122, which are optimized to balance the appropriate exhaust rate based on certain process conditions related to the chemical precursor gas and inert shielding gas flow rates. The "A" and "B" path flow rate controllers 1116, 1122 can be adjusted manually or automatically based on flow requirements and using measurement readings from the "A" and "B" path flow meters 1136, 1142 as feedback. In addition, the "A" and "B" path vacuum pressure gauges 1138, 1144 are used to measure the generated vacuum pressure. Dynamic control of the exhaust pressure and flow rate by adjusting the flow rate controllers 1116, 1122 can ensure that conditions throughout the deposition process are controlled and maintained over time. When there is powder buildup and accumulation detected in the exhaust channels and line connections, the two-way valve 1110 can be switched to engage the high-intensity exhaust flow path to maximize the exhaust pressure and flow rate generated by the "A" and "B" flow path venturi pumps 1106, 1108 to remove the accumulated powder from the lines. Switching of the two-way valve 1110 can be done manually or automatically, for example, during the deposition process, between each cycle of deposition, or when powder begins to accumulate. Check valves 1150, 1152 can be installed to prevent backflow of compressed air into the Y / T fittings 1112, 1114 when the normal-intensity or high-intensity exhaust flow paths are engaged.

[0116] In addition to monitoring the vacuum pressure generated by the venturi pumps 1106, 1108, vacuum pressure gauges 1132, 1138, 1144 can also be used to monitor for clogs in the lines. For example, two "A" channel vacuum pressure gauges 1132, 1138 are connected to the exhaust channels (e.g., channels 210-F, 210-R in FIG. 2 ) adjacent to the chemical precursor gas channel (e.g., channel 208 in FIG. 2 ) that is most sensitive to powder formation and accumulation. Clogging can occur in the powder collector 1130 and particle filter 1134, which are used to filter out fine powder to capture particulates and avoid clogging the venturi pump 1106, respectively. The vacuum pressure gauges 1132, 1138 can be used to determine where a clog occurs in the line, whether the blockage is upstream of the particle filter 1134 or downstream of the powder collector 1130. This allows the operator to quickly determine the location of the clog so that maintenance is more efficient. Both the powder collector 1130 and the particle filter 1134 can be equipped with a bypass circuit with a second powder collector 1230 and a second particle filter 1234 in parallel, as shown in FIG. 12. The second powder collector 1230 and the second particle filter 1234 can each be independently activated via respective bypass valves (not shown), which stop flow to the respective first powder collector 1130 and first particle filter 1134. This allows for maintenance without interruption to operation. Conversely, reactant channels that normally do not deliver gas will thus form powder. Therefore, multiple vacuum pressure gauges may not be required in the "B" flow path. In some examples, the "B" flow path vacuum pressure gauge 1144 may be omitted when pressure monitoring is not required.

[0117] If the line begins to become blocked, the vacuum pressure only begins to increase. One example is when powder accumulates around the inner wall of the tube to the point where flow begins to be restricted. For example, the "A" flow path can be connected to two exhaust channels (e.g., channels 210-F and 210-R in FIG. 2). A potential drawback of this configuration is that if one of the two tubes connected to the exhaust channel becomes clogged and the other does not, flow can still pass through the unclogged tube. This can affect process control and result in uncontrolled gas flow due to an imbalance in exhaust flow rates in the exhaust channels, which can lead to uneven coating deposition and powder formation in the deposition area and the possibility of powder settling on the substrate surface. One strategy is to match each exhaust channel (e.g., channels 210-F and 210-R in FIG. 2) with its own venturi pump circuit so that each of the lines connected to the exhaust channel can be maintained individually and independently. Another strategy is to use one venturi pump 1106, as shown in Figure 13, and fit each line connected to each exhaust channel with its own vacuum pressure gauge 1302 and manual or automatic on-off valve 1304, so that clogs in each line can be individually detected and cleared. The same approach shown in Figure 13 can also be configured to use one or more venturi pumps, for example, when multiple coating head modules are assembled.

[0118] Another exemplary evacuation system can be achieved by using one or more electrically driven mechanical vacuum pumps 1402 instead of a venturi pump, as shown in FIG.

[0119] FIG. 15 shows an example system 1500 with an environmental control chamber 1502 that may be useful for adjusting the local environment around a coating head 1504, such as any of the coating heads discussed elsewhere herein.

[0120] The environmental control chamber 1502 can be a box made of glass, plastic, or similar material. It can be transparent to allow its contents to be seen. The chamber 1502 can be sized to contain the coating head or heads 1504 and a portion of the substrate 204 being coated.

[0121] A humidifier / dehumidifier 1506 may be provided in the environmental control chamber 1502 to control the humidity level within the chamber 1502. The humidifier / dehumidifier 1506 may be located inside the chamber 1502 or may be located outside the chamber 1502 and may communicate humidified or dehumidified gas (e.g., air) with the chamber 1502.

[0122] A heater 1508 may be provided in the environmental control chamber 1502 to control the temperature within the chamber 1502. The heater 1508 may be located inside the chamber 1502 or may be located outside the chamber 1502 and may communicate a heated or cooled gas (e.g., air) with the chamber 1502.

[0123] A pump 1510 may be provided to the environmental control chamber 1502 to control the pressure level within the chamber 1502. The chamber 1502 has a slightly higher pressure than the wider environment (outside the chamber) and may be controlled to prevent particulates and other undesirable materials from entering the chamber 1502 and affecting the deposition process.

[0124] In another example, the pump 1510 is configured to create a slight negative pressure in the environmental control chamber 1502 compared to the larger environment, which may improve gas delivery to the substrate 204 by the coating head 1504. A blanket of inert gas may be pumped into the environmental control chamber 1502 to reduce particulates, contaminants, and the like.

[0125] A humidifier / dehumidifier 1506 , heater 1508 , and pump 1510 may be combined as a single unit that provides conditioned air (or other gas) inside the chamber 1502 .

[0126] Referring to FIG. 16A, an exemplary coating head 1600, such as any of the coating heads discussed elsewhere herein, may include channels with offset slit positions to prevent unintended mixing of gases.

[0127] The precursor and / or reactant channels 1602 may have end slits 1604 (through which gases exit to the substrate) offset 1606 in a direction away from the substrate 204 from end slits 1608 of nearby inert gas channels 1610. Exhaust channels 1612 positioned between the precursor / reactant channels 1602 and the inert gas channels 1610 may be offset in the same manner, by the same or a similar amount. This may encourage precursor / reactant gases to remain near the precursor and / or reactant channels 1602 (as shown by flow path 1614) and be drawn away from the substrate 204 by nearby exhaust channels 1612, rather than leaking beyond the inert gas channels 1610 (as shown by flow path 1616) and potentially interfering with other precursor / reactant gases. That is, the reduced gap 1618 between the slit 1608 of the inert gas channel 1610 and the substrate 204 can provide a sufficient obstacle to prevent unintended mixing of precursor and / or reactant gases. Examples of suitable offsets 1606 include 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, and 0.5 mm.

[0128] 16B shows an example coating head 1650, such as any of the coating heads discussed elsewhere herein, that includes channels with offset slit positions to prevent unintended mixing of gases. Coating head 1650 is similar to coating head 1600 of FIG. 16A, and only the differences will be discussed in detail.

[0129] The body of the coating head may be convexly chamfered or curved around the inert gas channel 1610 and the precursor and / or reactant channels 1602, as shown at 1652. That is, end slits 1604, 1608 of such channels 1602, 1610 may be provided at the apex. The end slits 1656 of the exhaust channel 1612 may be seated at respective valleys, each valley being offset (1654) in a direction away from the substrate 204 from the end slits 1608 and / or 1604 of the nearby inert gas channel 1610 and / or precursor and / or reactant channel 1602. The reduced gap 1618 between the slits 1608 of the inert gas channel 1610 and the substrate 204 may provide a sufficient obstruction to prevent unintended mixing of precursor and / or reactant gases. Examples of suitable offsets 1654 include 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, and 0.5 mm. Additionally, the chamfered or curved surface 1652 may provide less resistance to the intended flow of gas into the exhaust channel 1612.

[0130] Coating heads with peaks and valleys consistent with coating head 1650 have been tested and found to reduce the rate of powder generation. While such offsets are known for other purposes, it has been discovered that using an offset in a coating head as discussed herein is surprisingly effective in reducing the rate of powder generation.

[0131] Referring to FIG. 17 , for better context and clarity, an exemplary coating head 1700 is shown. The coating head 1700 may embody any of the features and aspects discussed with respect to the coating heads described elsewhere herein. The coating head 1700 includes a body 1702 provided with a channel (which may be modular). The channel may include a first portion 1704 that conveys gas laterally through the body 1702 and a second portion 1706 that conveys gas to / from the substrate (e.g., up and down in the figure) and terminates in a slit 1708 adjacent the substrate (not shown). Cross sections shown in other figures are generally oriented so that the viewer is looking in the sideways direction shown in FIG. 17 .

[0132] Additionally, it should be noted that the coating heads discussed herein can be made of any suitable material, such as plastic or metal. Plastic coating heads can be manufactured by 3D printing using a suitable resin. The advantages attributed to plastic coating heads can also be realized using coating heads made of suitable metals or other materials.

[0133] In light of the above, it should be clear that the techniques disclosed herein are useful for powder mitigation and exhaust management for thin film deposition. SALD, an open-air vapor deposition technique, typically uses a coating head with various gas channels for delivering chemical precursors, shielding gases, and / or exhaust channels for removing reaction products. Due to difficulties in proper gas isolation and powder mitigation, powder often generates problems such as fluid system blockages and poor coating properties. The techniques disclosed herein can be used to clear airborne particulates from substrate surfaces undergoing SALD processes. The techniques can also be used to treat and clean substrate surfaces for improved coating properties. Furthermore, the techniques provide a controlled methodology for removing excess precursor chemical gases, eliminating line clogging, and improving process reliability and uptime.

[0134] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the system or the disclosure. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. As used herein, the singular forms "a," "an," and "the" are intended to include the plural as well as the singular unless the context clearly indicates otherwise. It is further understood that the terms "comprise(s)" and / or "comprising," as used herein, specify the presence of stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0135] It should be appreciated that features and aspects of the various examples provided above may be combined into additional examples that are also within the scope of the present disclosure. Additionally, the figures are not to scale and may have exaggerated sizes and shapes for illustrative purposes.

Claims

1. 1. A spatial atomic layer deposition (SALD) system, comprising: A coating head is provided, the coating head comprising: a precursor gas channel configured to provide a precursor gas to the substrate; a reactant gas channel positioned forward of the precursor gas channel, the reactant gas channel configured to provide a reactant gas to the substrate; a series of inert gas channels positioned relative to the precursor gas channel and the reactant gas channel; Including, A SALD system, wherein each inert gas channel is configured to provide inert gas to the substrate and sweep unwanted material from the substrate.

2. 10. The SALD system of claim 1, wherein the series of inert gas channels are positioned before or after the reactant gas channel and the precursor gas channel.

3. 10. The SALD system of claim 1, wherein the series of inert gas channels is positioned between the reactant gas channel and the precursor gas channel.

4. a body provided with the precursor gas channel and the reactant gas channel; a module provided with said series of inert gas channels; Furthermore, The SALD system of claim 1 , wherein the module is removably attachable to the body.

5. 10. The SALD system of claim 1, further comprising a surface treatment device, a particulate monitoring device, an ultrasonic vibrator, a heater, a dehumidifier, an electrostatic charge generator, or a combination thereof attached to the coating head.

6. The SALD system of claim 1 , wherein the coating head further comprises a surface treatment on a surface of the body of the coating head adjacent the substrate.

7. 7. The SALD system of claim 6, wherein the surface treatment comprises a layer of octadecylphosphonic acid (ODPA).

8. a first exhaust flow path connected to an exhaust channel of the coating head adjacent to the precursor gas channel; a second exhaust passage connected to another exhaust channel of the coating head adjacent to the reactive gas channel; The SALD system of claim 1 further comprising:

9. 10. The SALD system of claim 8, further comprising a pressure gauge positioned in the first exhaust flow path or the second exhaust flow path, the pressure gauge configured to detect an obstruction in the first exhaust flow path or the second exhaust flow path.

10. a pump positioned in the first exhaust flow path or the second exhaust flow path; a flow rate controller connected to the pump; Furthermore, 9. The SALD system of claim 8, wherein the pump and flow rate controller is configured to increase the flow rate of exhaust through the first exhaust flow path or the second exhaust flow path to remove an obstruction.

11. 10. The SALD system of claim 1, further comprising an environmental control chamber in which the coating head is positioned, the environmental control chamber configured to control the temperature, pressure, and humidity of a local environment surrounding the coating head.

12. 10. The SALD system of claim 1, wherein an end slit of the precursor gas channel or the reactant gas channel is offset from an end slit of the inert gas channel in a direction away from the substrate.

13. 1. A spatial atomic layer deposition (SALD) system, comprising: A coating head is provided, the coating head comprising: a precursor gas channel configured to provide a precursor gas to the substrate; a reactant gas channel positioned forward of the precursor gas channel, the reactant gas channel configured to provide a reactant gas to the substrate; a series of exhaust channels positioned relative to the precursor gas channel and the reactant gas channel; Including, A SALD system, wherein each exhaust channel is configured to draw unwanted material from the vicinity of the substrate.

14. 14. The SALD system of claim 13, wherein the series of inert gas channels are positioned before or after the reactant gas channel and the precursor gas channel.

15. a body provided with the precursor gas channel and the reactant gas channel; a module provided with a series of exhaust channels; Furthermore, The SALD system of claim 13 , wherein the module is removably attachable to the body.

16. 14. The SALD system of claim 13, further comprising a surface treatment device, a particulate monitoring device, an ultrasonic vibrator, a heater, a dehumidifier, an electrostatic charge generator, or a combination thereof attached to the coating head.

17. The SALD system of claim 13 , wherein the coating head further comprises a surface treatment on a surface of the body of the coating head adjacent the substrate.

18. 20. The SALD system of claim 17, wherein the surface treatment comprises a layer of octadecylphosphonic acid (ODPA).

19. a first exhaust flow path connected to an exhaust channel of the coating head adjacent to the precursor gas channel; a second exhaust passage connected to another exhaust channel of the coating head adjacent to the reactive gas channel; The SALD system of claim 13 further comprising:

20. 20. The SALD system of claim 19, further comprising a pressure gauge positioned in the first exhaust flow path or the second exhaust flow path, the pressure gauge configured to detect an obstruction in the first exhaust flow path or the second exhaust flow path.

21. a pump positioned in the first exhaust flow path or the second exhaust flow path; a flow rate controller connected to the pump; Furthermore, 20. The SALD system of claim 19, wherein the pump and flow rate controller is configured to increase the flow rate of exhaust through the first exhaust flow path or the second exhaust flow path to remove an obstruction.

22. 14. The SALD system of claim 13, further comprising an environmental control chamber in which the coating head is positioned, the environmental control chamber configured to control the temperature, pressure, and humidity of a local environment surrounding the coating head.

23. 14. The SALD system of claim 13, wherein an end slit of the precursor gas channel, the reactant gas channel, or the exhaust channel is offset from an end slit of the inert gas channel in a direction away from the substrate.

24. 1. A spatial atomic layer deposition (SALD) system, comprising: A coating head is provided, the coating head comprising: a precursor gas channel configured to provide a precursor gas to the substrate; a reactant gas channel positioned forward of the precursor gas channel, the reactant gas channel configured to provide a reactant gas to the substrate; a series of alternating inert gas channels and exhaust channels positioned relative to the precursor gas channels and the reactant gas channels; Including, 1. A SALD system, wherein each inert gas channel is configured to provide inert gas to the substrate and sweep unwanted material from the substrate, and each exhaust channel is configured to draw unwanted material from the vicinity of the substrate.

25. a body provided with the precursor gas channel and the reactant gas channel; a module provided with a series of alternating inert gas channels and exhaust channels; Furthermore, 25. The SALD system of claim 24, wherein the module is removably attachable to the body.

26. 25. The SALD system of claim 24, further comprising a surface treatment device, a particulate monitoring device, an ultrasonic vibrator, a heater, a dehumidifier, an electrostatic charge generator, or a combination thereof attached to the coating head.

27. 25. The SALD system of claim 24, wherein the coating head further comprises a surface treatment on a surface of the body of the coating head adjacent the substrate.

28. 28. The SALD system of claim 27, wherein the surface treatment comprises a layer of octadecylphosphonic acid (ODPA).

29. a first exhaust flow path connected to an exhaust channel of the coating head adjacent to the precursor gas channel; a second exhaust passage connected to another exhaust channel of the coating head adjacent to the reactive gas channel; 25. The SALD system of claim 24, further comprising:

30. 30. The SALD system of claim 29, further comprising a pressure gauge positioned in the first exhaust flow path or the second exhaust flow path, the pressure gauge configured to detect an obstruction in the first exhaust flow path or the second exhaust flow path.

31. a pump positioned in the first exhaust flow path or the second exhaust flow path; a flow rate controller connected to the pump; Furthermore, 30. The SALD system of claim 29, wherein the pump and flow rate controller is configured to increase the flow rate of exhaust through the first exhaust flow path or the second exhaust flow path to remove an obstruction.

32. 25. The SALD system of claim 24, further comprising an environmental control chamber in which the coating head is positioned, the environmental control chamber configured to control the temperature, pressure, and humidity of a local environment surrounding the coating head.

33. 25. The SALD system of claim 24, wherein an end slit of the precursor gas channel, the reactant gas channel, or the exhaust channel is offset from an end slit of the inert gas channel in a direction away from the substrate.

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