The present disclosure relates generally to thin film deposition and, more specifically to an apparatus and method for thin film deposition.
Techniques such as sputtering, evaporation, and chemical vapor deposition are used to deposit films for many applications (e.g. modern electronics, optical components, display technologies, food packaging, etc.). For these applications, improved control over the film thickness is needed. Atomic layer deposition (ALD) is the best technique for producing films with nanometre-scale thickness control, as it deposits a film one atomic layer at a time. As feature sizes continue to decrease in applications such as integrated circuits and memory devices, ALD is becoming the preferred (and in some cases only) option for depositing some film components. Weaknesses associated with conventional temporal ALD include its speed (it is a relatively slow batch process) and its need for a vacuum chamber, which hinders its scalability.
Conventional temporal ALD operates by sequentially inserting two or more chemical precursor gases into a vacuum chamber, with evacuation and purge steps in between the exposures. If suitable experimental conditions are used, a single atomic layer of the material is formed after each sequence, and the sequence is repeated multiple times to build up a film. Hence conventional temporal ALD separates the two precursor gases in time. In contrast, spatial atomic layer deposition (SALD) techniques have been developed, which separate the two precursors in space, rather than in time. The substrate is moved between the two precursor gases to replicate the sequential exposures. This eliminates or reduces the evacuation and purge steps that make temporal ALD slow.
Atmospheric Pressure SALD (AP-SALD) can produce thin film layers of materials (e.g. metal oxides) that are compact, conformal, and pinhole-free and can deposit thin films at approximately room temperature. This is one to two orders of magnitude faster than conventional ALD, and is scalable. Notably, AP-SALD is also compatible with roll-to-roll manufacturing and demonstrated to work on glasses, glasses coated with transparent conducting oxides, semiconducting wafers, foils, fabrics and plastic surfaces. These advantages make AP-SALD very attractive for high-throughput manufacturing of large-area, low-cost electronics, such as photovoltaics, batteries, and microelectronics, as well as functional coatings, such a barrier films and antimicrobial coatings.
Therefore, there is provided a novel apparatus and method of thin film deposition.
The present disclosure includes a novel thin, film or thin layer deposition method generally including at least one reactor head that is modular and configurable for functional flexibility and scalability to produce thin films. Thin layer deposition may include spatial atomic layer deposition and/or chemical vapor deposition. The reactor head may include different types of components such as, but not limited to, precursor gas slits, a plasma source, exhaust slits, a heating channel and/or a cooling channel for different types of depositions. The interspaced elevation and widths of each component may be adjusted to facilitate and control the flow of gases. A positioning system with a mounting element for the reactor head is configured to adjustably maintain the orientation and position of the reactor head relative to the substrate(s). The positioning system may be configured with at least one displacement measuring device and at least one actuator. A heating stage with suction may be used to heat a substrate and to hold substrates of different size, geometry, and thickness. The heating stage may be configured with zone-controlled heating to provide different temperatures at different locations. A linear motor positioning system may be used to oscillate the substrate relative to the modular reactor head. The system may deposit thin films by spatial atomic layer deposition or chemical vapor deposition and produce films with uniform thickness and/or composition or varying thickness and/or composition.
In one aspect of the disclosure, there is provided a modular reactor head for use with a thin film deposition system including a set of modular components, the set of module components adjacent each other in a first direction within the reactor head; wherein the set of modular components may be positioned relative to each other in a second direction, the second direction substantially perpendicular to the first direction; wherein the set of modular components include at least one precursor gas modular component for depositing at least two precursor gases onto a substrate.
In another aspect, the set of modular components includes at least two precursor gas modular components. In a further aspect, the at least two precursor includes a reactor channel; and a reactor channel opening. In a further aspect, the reactor channel opening delivers a gaseous or liquid material with a higher exit velocity at one end of the reactor channel opening than at an opposite end of the reactor channel opening. In an aspect, the set of modular components includes at least one of a precursor fluid component, an exhaust modular component, an inert gas modular component, a temperature control modular component, chemical modular component, a cleaning modular component and a plasma source modular component. In a further aspect, the temperature control modular component includes a metal plate for controlling a temperature of a modular component adjacent the temperature control modular component. In yet a further aspect, the temperature control modular component includes a reactor channel for either receiving a cooling liquid to cool the metal plate or a heating liquid to heat the metal plate. In yet another aspect, the set of modular components are mounted at predetermined heights with respect to each other. In another aspect, the precursor fluid modular component includes actuators to control precursor fluid deposition.
In another aspect of the disclosure, there is provided a thin film deposition system including a substrate stage for supporting a substrate; a modular reactor head for depositing thin films onto the substrate, the modular reactor head including a set of modular components, the set of module components adjacent each other in a first direction within the reactor head; wherein the set of modular components may be positioned relative to each other in a second direction, the second direction substantially perpendicular to the first direction; wherein the set of modular components include at least one precursor gas modular component for depositing at least two precursor gases onto a substrate; and a modular reactor head positioning system for positioning the modular reactor head with respect to the substrate on the substrate stage.
In a further aspect, the modular reactor head positioning system includes a linear displacement system. In yet another aspect, the linear displacement system includes a set of displacement measuring devices; and a set of linear actuators. In yet a further aspect, the modular reactor head positioning system including a leveling system for gap control between the modular reactor head and the substrate stage. In an aspect, the substrate stage includes a vacuum system for holding the substrate against the substrate stage. In another aspect, the substrate stage includes an upper plate for supporting the substrate; and a heating component for heating the upper plate. In yet a further aspect, the substrate stage includes a linear motor system.
For a clear understanding of the disclosure, some embodiments of the present disclosure are illustrated as an example and are not limited to the figures of the accompanying drawings, in which:
The terminology used herein is for the purpose of describing specific embodiments only and is not intended to be limiting of the system or 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 forms as well as the singular forms, unless the context clearly indicates otherwise. It will be further understood that the terms “comprise(s)” and/or “comprising,” when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.
The phrase “thin layer” or “thin film” as used herein refers to a layer of material deposited by spatial atomic layer deposition (SALD) and/or spatial chemical vapor deposition (SCVD). It has been shown that by controlling the processing conditions so that the precursor gases can mix in the gas phase (are not isolated from each other), chemical vapor deposition can occur instead of atomic layer deposition. This results in a higher thin film deposition rate, which is advantageous for some applications, while still producing conformal, pinhole-free films, with accurate control over the film thickness at the nanometer scale. As such, the phrase “thin layer deposition” refers to spatial atomic layer deposition and/or spatial chemical vapor deposition.
In the current embodiment, the modular reactor head 102, reactor head positioning system 104, and substrate stage 108 are positioned in a lower cabinet 110. Equipment to deliver precursor gases to the modular reactor head is placed in the upper cabinet 112. This equipment will be well understood by one skilled in the art. In one embodiment, the equipment may include equipment for generating gases 180 of precursor chemical such as, but not limited to, bubblers and bubbler heaters, equipment to control a flow rate 182 of the gases such as, but not limited to mass flow controllers and equipment 184 to distribute the gases, such as, but not limited to valves, tubing and manifolds. In one embodiment, the precursor gases may be directly inputted into the upper cabinet from an external source or may be generated from liquid or solid chemicals by bubbling or nebulizing a liquid chemical material or heating a solid chemical material. In another embodiment, instead of or along with, a precursor gas, a liquid may be transmitted from the upper cabinet to the modular reactor head.
In one embodiment, the reactor head 102 may be oriented parallel to the substrate stage 108 with the set of modular components 114 adjacent each other in a plane oriented along a first direction 128. A length of each of the set of modular components 114 may be seen as extending in a second direction 126 substantially perpendicular to the first direction 128. The reactor head 102 may be positioned at a distance from the substrate 106, where the distance may be measured along a direction 130 substantially orthogonal to the first and second directions. In some embodiments, the distance may be measured at an angle from the reactor head. Each of the set of modular components 114 may perform different functionalities as discussed in more detailed below.
In one embodiment, as shown in dotted lines in
If a modular component 114 is supplied with a precursor gas that passes through the modular component 114 from the precursor gas source to the substrate, the modular component 114 may be seen as a precursor gas component and the reactor channel opening referred to as a precursor gas opening. As thin layer deposition typically requires at least two different precursor gases, at least two of the modular components of a reactor head will provide the functionality of a precursor gas modular component. Alternatively, if a modular component 114 is supplied with an inert gas, the modular component may be seen as an inert gas modular component and the reactor channel opening referred to as an inert gas opening. If a modular component 114 is supplied with a precursor fluid, e.g. liquid and actuator, the modular component may be seen as a precursor fluid modular component and be used to introduce a different way of nanomanufacturing techniques, such as but not limited to, selective-area deposition, slot-die coating, inkjet printing or spray deposition. If a modular component 114 is coupled to a vacuum source to draw gas into its reactor channel 132 through the reactor channel opening, the modular component 114 may be seen as an exhaust modular component and the reactor channel opening referred to as an exhaust opening. A modular component 114 may be seen as a thermal control modular component whereby thermal fluid may pass through the reactor channel. In a thermal control modular component, the reactor channel 132 does not include a reactor channel opening. If the thermal control modular component provides heat, the modular component may be referred to as a modular heating component. If the thermal control modular component provides cooling, the thermal component may be referred to as a modular cooling component. If plasma is introduced into the reactor channel, the modular component may be seen as a plasma source or plasma modular component. Alternatively, if the modular component 114 is supplied with a chemical, such as, but not limited to, a cleaning agent or supplied with compressed air, the modular component may be seen as a cleaning modular component and may be used to clear the reactor channel for maintenance purposes or for possibly cleaning the substrate, if necessary. In alternative embodiments, the chemical may be a reducing agent whereby a material (such as a metal) on the substrate may catalyze other materials (such as metal ion salts) due to the reducing agent. In another embodiment, the chemical may used to perform a surface modification treatment or etching on the substrate.
In the present embodiment, the set of head modular components 114 is arranged to effectively separate the precursor gases for atomic layer deposition (ALD), by positioning at least one of the inert gas components 120 and at least one of the exhaust components 122 between the first precursor gas component 116 and the second precursor gas component 118. The arrangement of modular components 114 is flexible so that in alternative embodiments the arrangement of modular components 114 may be configured to mix the precursor gases (e.g. the first and second precursor gas components 116 and 118 could be placed directly adjacent to each other, without exhaust components 122 or inert gas components 120 in between) for chemical vapor deposition (CVD).
Each modular reactor component 114 may be positioned with a long axis of the modular reactor component 114 parallel with the second direction 126. The set of modular components 114 may be arranged to position each modular component 114 adjacent to at least one other modular component 114 where the plurality of modular components 114 extends in the first direction 128. In other words, the individual modular components 114 of the modular reactor head 102 are stacked horizontally for easy assembly. The sequence of the modular components 114 depends on the configuration of the reactor head 102, where the sequence may be altered by altering the position of one or more of the modular components 114 (i.e. changing the sequence).
The modular reactor head of the disclosure may allow a thin film deposition system to be scaled easily by increasing the number of individual modular components or by increasing the length of the reactor channel openings. By increasing the number of precursor gas modular components, or by increasing the number of reactor channel openings in a modular component, the number of ALD cycles that occur each time the substrate(s) passes underneath the modular reactor head is increased.
The modular reactor head 102 may allow functional flexibility, where different types of individual modular components can be easily added, such as cooling channels, heating channels, plasma sources, and precursor gas modular components having reactor channel openings with unique features (for example non-uniform gas delivery to produce film gradients, as will be discussed below). Each modular component may be customized, installed or swapped out, for different functions and purposes.
The deposition system may be equipped with loading and unloading mechanisms for the substrates, such as robotic arms, to fully automate the manufacturing process. The deposition system may also be compatible with roll to roll technologies, such as film deposition on plastics, fabrics or foils. For roll-to-roll systems, the substrate stage may be configured to be compatible with a continuous web of plastic, fabric or foil, for example the substrate stage may include rollers to hold a portion of the web proximate the reactor head at an at least approximately constant distance from the reactor head, and the system may control the position of the web and number of depositions to achieve a desired thickness on the web by rolling/unrolling the web.
The upper plate 902 is separated from the vacuum reservoir 908 by a thermal-insulation layer 906, which may be an air gap, to thermally insulate the vacuum reservoir 908 from the upper plate 902 that is heated by a heating element 905. A substrate (not shown) may be placed on the upper plate 902, and when suction is provided, the plurality of holes 904 in the upper plate 902 may firmly hold the substrate in place atop the upper plate 902. In other words, the vacuum reservoir 908 coupled to the plurality of holes 904 in the upper plate 902 form a mechanism to hold a substrate to the substrate stage 900.
In one embodiment, the upper plate 902 is offset from the vacuum reservoir 908 (which provides the suction to hold the substrates 912 down) by a predetermined distance, such as approximately 10 mm or more, to provide the air gap 9 for insulation. As discussed above, insulation material can be added to isolate the vacuum reservoir 908 and underlying system components from the heat generated by the heating element 905.
Although not necessary in every embodiment, the thin film, or thin layer, deposition system of the disclosure may include a substrate positioning system that controls the position of the substrate held by the substrate stage relative to the modular reactor head. For example, the substrate positioning system may be a linear motor positioning system that oscillates the substrate held by the substrate stage and thereby enables high-throughput and high precision deposition. The linear motor based substrate positioning system may maintain the top surface of a substrate at a uniform height during motion, which enables accurate control of the space between the modular reactor head and a substrate when combined with the reactor positioning system.
The linear motor positioning system 1801 may also enable non-uniform film deposition by oscillating the substrate stage 1800 and substrate with varying travel distances. The oscillating approach allows this technology to make thickness and composition gradients in the direction of substrate oscillation (direction 128 from
Overall, the thin film deposition system of the present disclosure may deposit a film where a composition or thickness gradient may be produced across the width of the film using precursor gas reactor channel openings that have customized geometries. A different thickness or composition gradient may be produced across the width of the film by varying the travel pattern of the heated substrate stage.
At 1902, a substrate is loaded onto a substrate stage. The substrate stage may be part of a thin film deposition system. The substrate stage may include a vacuum reservoir and a plurality of holes. At 1904, the substrate is secured to the substrate stage with suction from the vacuum reservoir. The suction may be provided to the substrate via the plurality of holes.
At 1906, a gap between the modular reactor head and the substrate is adjusted using the reactor head positioning system. The reactor head positioning system may be part of a thin film deposition system. Adjusting the gap includes controlling a distance between the modular reactor head and the substrate.
At 1908, multiple precursors, including precursor gases, are delivered simultaneously and continuously to the modular reactor head. The multiple precursor gases pass through the modular reactor head by passing through a respective reactor channel and out a respective reactor channel opening oriented towards the substrate. The position at which each precursor gas contacts the substrate is determined by the position of each respective precursor gas modular component within the modular reactor head.
At 1910, the substrate is oscillated underneath the modular reactor head and material is deposited by the modular components onto the substrate and thereby form a film. The substrate may be oscillated with a substrate positioning system. The substrate positioning system may be part of a thin film deposition system.
At 1912, if the thickness of the deposited film is not sufficient, the method returns to 1910. If the thickness of the film is sufficient, then at 1914 the substrate is removed from the substrate stage.
At 2002, a continuous web of substrate wound around a first roll is loaded onto a first roller and coupled to a second roll mounted on a second roller.
At 2004, the tension of the substrate between the first roller and the second roller is adjusted automatically. At 2006, the temperature of the substrate is adjusted. Temperature adjustment may include heating the substrate.
At 2008, a gap between the modular reactor head and the substrate is adjusted using the reactor head positioning system. The reactor head positioning system may be part of a thin film deposition system. Adjusting the gap includes controlling a distance between the modular reactor head and the substrate.
At 2010, multiple precursors, including precursor gases, are delivered simultaneously and continuously to the modular reactor head. The multiple precursor gases pass through the modular reactor head by passing through a respective reactor channel and out a respective reactor channel opening oriented towards the substrate. The position at which each precursor gas contacts the substrate is determined by the position of each respective precursor gas modular component within the modular reactor head.
At 2012, the substrate is wound underneath the modular reactor head and material (such as the precursor gases) are deposited on the substrate and thereby form a film. If the substrate is wound around the first roll, the substrate may be wound underneath the modular reactor head by winding the substrate from the first roll to the second roll. If the substrate is wound around the second roll, the substrate may be wound underneath the modular reactor head by winding the substrate from the second roll to the first roll.
At 2014, if the thickness of the deposited film is not sufficient, the method returns to 2012. If the thickness of the film is sufficient, then at 2016 the web of substrate is unloaded.
In some embodiments, the disclosure may be directed at a modular reactor head that can be equipped with different components (heating channels, cooling channels, plasma sources, etc.) and whose components can be arranged and positioned in a variety of configurations such as, but not limited to a reactor head with modular components and adjustable positions and heights for each component that provides the ability to control gas flows and switch between ALD and CVD system configurations; a cooling/heating channel to control the temperature of the adjacent precursor gas slit to obtain desired thin film deposition conditions; a plasma source; and/or a scalable reactor slits that can increase the throughput of deposition.
In another embodiment, the disclosure may be directed at a system for positioning a reactor head relative to the substrate(s). The reactor head may be modular or non-modular. The system may further control the spacing between the reactor head and substrate and hence allows switching between ALD and CVD modes
In another embodiment, the disclosure may be directed at a heating substrate stage with suction and/or localized temperature control. In one embodiment, the heating substrate stage may include a vacuum holding mechanism capable of holding any substrate geometries and thicknesses. In another embodiment, the heating substrate stage may include thermal insulation of the heated substrate stage from other system components.
In another embodiment, the disclosure may be directed at customizable precursor gas slit designs that can produce uniform or non-uniform flow profiles from the slits that enables the deposition of films with non-uniform thickness and/or composition perpendicular to the direction of substrate motion
In a further embodiment, the disclosure may be directed at a linear motor positioning system that oscillates the substrate(s) relative to the modular reactor head that a) dampens vibrations and maintains substrate(s) at a uniform height during their oscillation to allow accurate control of the spacing between the substrate(s) and modular reactor head; and/or b) enables the deposition of films with non-uniform thickness and/or composition in the direction of the substrate motion. This can be combined with the customizable precursor gas slit designs to produce films with different thickness and composition gradients in orthogonal directions.
In yet a further embodiment, the disclosure may be directed at multiple deposition systems can be equipped with roll-to-roll technologies and/or substrate loading and unloading mechanisms for high-throughput production.
In another embodiment, the disclosure may be directed at depositing a thin layer of material on a fabric with the modular reactor head, for example ALD of copper oxide to a non-woven fabric for a N95 mask. Conventional spray coating or wet coating of copper oxide to a fabric typically fills in the pores of the fabric which may affect the performance of the mask, however CVD and/or ALD of copper oxide may provide an antiviral coating to the mask with a reduced effect on mask performance relative to conventional coating techniques.
Although the present disclosure has been illustrated and described herein with reference to preferred embodiments and specific examples thereof, it will be readily apparent to those of ordinary skill in the art that other embodiments and examples may perform similar functions and/or achieve like results. All such equivalent embodiments and examples are within the spirit and scope of the present disclosure.
In the preceding description, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the embodiments. However, it will be apparent to one skilled in the art that these specific details may not be required. In other instances, well-known structures may be shown in block diagram form in order not to obscure the understanding. For example, specific details are not provided as to whether elements of the embodiments described herein are implemented as a software routine, hardware circuit, firmware, or a combination thereof.
The disclosure claims priority from U.S. Provisional Application No. 62/949,798 filed Dec. 18, 2019, which is hereby incorporated by reference.
Filing Document | Filing Date | Country | Kind |
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PCT/CA2020/051748 | 12/18/2020 | WO | 00 |
Number | Date | Country | |
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62949798 | Dec 2019 | US |