Linear metal evaporation source for vacuum coating

Abstract

This invention relates to the field of vacuum coating technology and discloses a linear metal evaporation source for vacuum coating. The linear metal evaporation source of this invention includes a container, a nozzle, and a crucible. The container includes a metal outer cover and an inner liner, with heat-insulating material filling the space between the outer cover and the inner liner. The inner liner is a heater, and its cavity includes a primary evaporation zone, a pressurization zone, a secondary evaporation zone, and a heating zone. The nozzle has a slit-shaped nozzle orifice and is located at the top of the inner liner. The crucible is located within the primary evaporation zone. The linear metal evaporation source of this invention is placed within the vacuum chamber of a vacuum coating apparatus. The inner liner heats the metal to be coated in the primary evaporation zone, causing the metal to vaporize and reach saturated vapor pressure. The metal vapor is transported to the nozzle at saturated vapor pressure, and the nozzle ejects the metal vapor in a linear jet manner, depositing it on the workpiece to form a uniform and dense metal coating layer. This results in high coating efficiency and good film quality.

Description

Technical Field

[0001] This invention relates to the field of vacuum coating technology, specifically to a linear metal evaporation source for vacuum coating. Background Technology

[0002] Vacuum coating technology has been widely used in applications such as photovoltaic cell film preparation, lithium battery current collector film preparation, capacitor conductive film preparation, and OLED film preparation. As one of the emerging high-tech industry application technologies, its technical methods and applications have developed rapidly in recent years.

[0003] However, the current manufacturing methods, processing quality, and efficiency of micron-thickness conductive metal films lag significantly behind high-end industry applications. For example, composite copper and aluminum foils used as current collectors in lithium batteries are generally produced using calendering, electrophoretic plating, and traditional vacuum deposition methods. These methods are energy-intensive, polluting, and produce extremely low processing quality and efficiency, far exceeding the demands of rapidly developing emerging industries such as energy storage and new energy power generation. The main reasons for this situation are:

[0004] First, traditional coating methods are not suitable for preparing large-area metal thin film products, and are seriously lacking in film uniformity and process repeatability.

[0005] Secondly, although vacuum coating belongs to the category of environmentally friendly advanced manufacturing technology, due to the high-temperature properties of copper and aluminum metal evaporation and the expanding demands of application industries for product specifications and production capacity, the existing coating equipment and the technical methods used have problems such as low processing precision, obvious inherent defects in the film, low production efficiency, lack of controllability and continuous working capability.

[0006] Therefore, how to design a suitable vacuum coating technology to improve coating quality and efficiency, reduce manufacturing costs and raw material consumption, and simplify the manufacturing process is a technical problem faced by technicians in the industry. Summary of the Invention

[0007] The purpose of this invention is to provide a linear metal evaporation source for vacuum coating to solve the problems mentioned in the background art.

[0008] This invention provides a linear metal evaporation source for vacuum coating, comprising: a container, a nozzle, and a crucible;

[0009] The container includes: a metal outer casing and an inner liner;

[0010] The inner liner is disposed inside the metal outer cover, and the space between the inner liner and the metal outer cover is filled with heat-insulating material;

[0011] The inner liner cavity includes, from bottom to top, a primary evaporation zone, a pressurization zone, a secondary evaporation zone, and a heating zone;

[0012] The inner liner is made of graphite. The inner liner sidewalls of the primary evaporation zone, the pressurization zone, the secondary evaporation zone and the heating zone are electrically connected to an external power source to form a heater inside the container to heat the corresponding areas.

[0013] The nozzle has a slit-shaped nozzle orifice and is located at the top of the inner liner, communicating with the heating zone;

[0014] The crucible is placed in the primary evaporation zone and is used to hold the coating metal raw material;

[0015] The linear metal evaporation source is located in the vacuum chamber of the vacuum coating equipment. The primary evaporation zone is used to heat the coating metal to vaporization. The pressurization zone, the secondary evaporation zone, and the heating zone are used to transport the coating metal vapor to the nozzle at saturated vapor pressure. The nozzle is used to eject the coating metal vapor in a linear jet to form a uniform and dense film layer on the coated workpiece.

[0016] Based on the above scheme, the linear metal evaporation source for vacuum coating of the present invention comprises a container, a nozzle, and a crucible. The container includes a metal outer cover and an inner liner, with the inner liner disposed inside the metal outer cover. A heat-insulating material is filled between the inner liner and the metal outer cover. The inner liner is made of graphite. The sidewalls of the primary evaporation zone, pressurization zone, secondary evaporation zone, and heating zone of the inner liner are respectively connected to a power source. The nozzle has a slit-shaped nozzle orifice and is located at the top of the inner liner. The crucible is disposed within the primary evaporation zone. The linear metal evaporation source for vacuum coating of the present invention is disposed within the vacuum chamber of a vacuum coating equipment, and the metal raw material for coating is placed inside the crucible. The inner liner of the container directly forms a heater within the container, heating the metal for coating in the primary evaporation zone, causing the metal to vaporize and evaporate to reach saturated vapor pressure. During the transport of the coating metal vapor to the nozzle, the pressurization zone, secondary evaporation zone, and heating zone of the inner tank continuously heat the coating metal vapor, ensuring that the coating metal vapor is transported to the nozzle at the top of the inner tank at saturated vapor pressure. The nozzle then ejects the coating metal vapor in a linear jet. The workpiece to be coated passes through the spray zone at the top of the nozzle at a certain speed, and the coating metal vapor is deposited on the workpiece (substrate), forming a uniform and dense metal coating layer.

[0017] In one feasible solution, the nozzle is made of graphite and is electrically connected to an external power source.

[0018] In one feasible solution, temperature control thermocouples are provided at the primary evaporation zone, the pressurization zone, the secondary evaporation zone, the heating zone, and the nozzle.

[0019] In one feasible embodiment, the cross-section of the primary evaporation zone is arc-shaped, and the cross-section of the pressurization zone is rectangular.

[0020] The top opening of the primary evaporation zone is connected to the pressurization zone, and the width of the pressurization zone is smaller than the diameter of the primary evaporation zone.

[0021] In one feasible approach, the cross-section of the secondary evaporation zone is conical;

[0022] The large conical end of the secondary evaporation zone is connected to the pressurization zone.

[0023] In one feasible solution, the cross-section of the heating zone is rectangular and connected to the conical small end of the secondary evaporation zone.

[0024] In one feasible solution, the nozzle is conical;

[0025] The large conical end of the nozzle is connected to the heating zone.

[0026] In one feasible solution, the thermal insulation material is ceramic fiber.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The inner liner forms a self-heating body, which heats and controls the temperature of each area of ​​the cavity separately, ensuring a high degree of controllability, uniformity and stability of the coating metal vapor, and delivering the vapor to the nozzle in a saturated vapor pressure state, providing a high level of process repeatability, evaporation rate adjustment response sensitivity and operability under a wide range of working conditions.

[0029] 2. The nozzle is an electrothermal graphite heating element, which has the freedom to control temperature and can adapt to the temperature characteristics of different coating materials, perfectly solving the problem of nozzle temperature control. It avoids pinhole defects in the coating layer and effectively suppresses steam condensation at the nozzle.

[0030] 3. The nozzle is conical, which can suppress the amount of heat radiation from the evaporation source to the organic material substrate to the greatest extent, thereby significantly improving the melting threshold of the organic material substrate.

[0031] 4. It can deposit a film thickness of more than 1 micrometer in one go, which can meet the effective width of substrates of more than 800 mm and the travel speed of substrates of more than 50 meters / minute. The metal film is uniform and dense, and there are no density steps or stress nodes in the depth direction and the entire extension direction of the film.

[0032] 5. The coating process does not use any polluting raw materials, nor does it generate or emit any polluting substances. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of a linear metal evaporation source for vacuum coating in an embodiment of the present invention.

[0035] Numbering on the map:

[0036] 1. Container; 11. Metal outer casing; 12. Inner liner; 1201. Primary evaporation zone; 1202. Pressurization zone; 1203. Secondary evaporation zone; 1204. Heating zone; 13. Thermal insulation material; 2. Nozzle; 21. Spray nozzle; 3. Crucible. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0039] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0040] The technical solution of the present invention will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0041] As described in the background section of this application, vacuum coating has been widely used, such as in the preparation of photovoltaic cell films, lithium-ion battery current collector films, capacitor conductive films, and OLED films. As one of the emerging high-tech industrial application technologies, its technical methods and applications have developed rapidly in recent years.

[0042] The inventors of this application have discovered that current manufacturing methods, processing quality, and efficiency of micron-thickness conductive metal films are severely lagging behind high-end industry applications. For example, composite copper and aluminum foils used as current collectors in lithium batteries are generally produced using calendering, electrophoretic plating, and traditional vacuum deposition methods. These manufacturing processes are energy-intensive, highly polluting, and produce extremely low processing quality and efficiency, far behind the demands of rapidly developing emerging industries such as energy storage and new energy power generation.

[0043] To address the aforementioned problems, the inventors of this application have proposed a technical solution, the specific embodiments of which are as follows:

[0044] Figure 1 This is a schematic diagram of a linear metal evaporation source for vacuum coating in an embodiment of the present invention.

[0045] like Figure 1 As shown, the linear metal evaporation source for vacuum coating in this embodiment includes: a container 1, a nozzle 2, and a crucible 3.

[0046] Container 1 includes: a metal outer casing 11 and an inner liner 12.

[0047] The metal outer casing 11 of container 1 is made of high-temperature resistant metal material and can adapt to the high-temperature coating environment.

[0048] The inner liner 12 is located inside the metal outer cover 11, and the top of the inner liner 12 is flush with the top of the metal outer cover 11. An insulation layer is provided between the outer wall of the inner liner 12 and the inner wall of the metal outer cover 11, and heat insulation material 13 is filled in the insulation layer between the inner liner 12 and the metal outer cover 11.

[0049] The inner liner 12 has a hollow structure with an internal cavity, and the material of the inner liner 12 is graphite.

[0050] The cavity of the inner liner 12 includes, from bottom to top, a primary evaporation zone 1201, a pressurization zone 1202, a secondary evaporation zone (homogenization zone) 1203, and a heating zone 1204. The primary evaporation zone 1201, the pressurization zone 1202, the secondary evaporation zone (homogenization zone) 1203, and the heating zone 1204 of the inner liner 12 are connected in sequence.

[0051] The inner liner 12's primary evaporation zone 1201, pressurization zone 1202, secondary evaporation zone 1203, and heating zone 1204 inner liner sidewalls (i.e., graphite) are electrically connected to an external power source. The inner liner 12's sidewalls form a self-heating heater within the container 1, enabling separate heating of each area of ​​the inner liner 12's cavity.

[0052] The crucible 3 is located at the bottom of the cavity of the inner liner 12, that is, within the primary evaporation zone 1201 of the inner liner 12. The metal raw material for coating is placed in the crucible 3 for heating.

[0053] The nozzle 2 has a slit-shaped nozzle 2, which is located at the top of the inner liner 12 and is connected to the heating zone 1204 of the inner liner 12.

[0054] In this embodiment, the linear metal evaporation source is installed in the sealed vacuum chamber of the vacuum coating equipment, and the width of the linear metal evaporation source in the front-to-back direction corresponds to the width of the workpiece to be coated.

[0055] The raw metal material for coating is placed in a crucible. The inner liner of the container heats the metal in the primary evaporation zone, causing it to vaporize and reach saturated vapor pressure. During transport to the nozzle, the inner liner continuously heats the metal vapor in the pressurization zone, secondary evaporation zone, and heating zone. The temperatures in these zones increase gradually, maintaining the metal vapor at saturated vapor pressure. This saturated vapor pressure is then transported to the nozzle at the top of the inner liner, where it is ejected as a linear jet. The workpiece to be coated passes through the spray zone at the top of the nozzle at a certain speed, and the metal vapor deposits on the workpiece (substrate), forming a uniform and dense coating layer.

[0056] As can be seen from the above, the linear metal evaporation source for vacuum coating in this embodiment comprises a container, a nozzle, and a crucible. The container includes a metal outer casing and an inner liner, with the inner liner placed inside the metal outer casing. Thermal insulation material is filled between the inner liner and the metal outer casing. The inner liner is made of graphite. The sidewalls of the primary evaporation zone, pressurization zone, secondary evaporation zone, and heating zone of the inner liner are respectively connected to a power source. The nozzle has a slit-shaped nozzle orifice and is located at the top of the inner liner. The crucible is placed within the primary evaporation zone. The linear metal evaporation source for vacuum coating of this invention is located within the vacuum chamber of a vacuum coating equipment, and the metal raw material for coating is placed inside the crucible. The inner liner of the container directly forms a heater within the container, heating the metal for coating in the primary evaporation zone, causing the metal to vaporize and evaporate to reach saturated vapor pressure. During the transport of the coating metal vapor to the nozzle, the pressurization zone, secondary evaporation zone, and heating zone of the inner tank continuously heat the coating metal vapor, ensuring that the coating metal vapor is transported to the nozzle at the top of the inner tank at saturated vapor pressure. The nozzle then ejects the coating metal vapor in a linear jet. The workpiece to be coated passes through the spray zone at the top of the nozzle at a certain speed, and the coating metal vapor is deposited on the workpiece (substrate), forming a uniform and dense metal coating layer.

[0057] Optionally, in this embodiment, the linear metal evaporation source for vacuum coating has a nozzle 2 made of graphite and is electrically connected to an external power source.

[0058] In this embodiment, the nozzle is an independent electrothermal graphite heater. The nozzle is individually heated and its temperature controlled by a controller, adapting to the temperature characteristics of different coating materials. This ensures that the coating metal vapor at saturated vapor pressure remains within the nozzle, effectively suppressing vapor condensation and preventing pinhole defects in the film layer during substrate deposition. The self-heating nozzle structure perfectly solves the technical challenge of controlling the nozzle temperature.

[0059] Furthermore, in this embodiment, the linear metal evaporation source for vacuum coating is equipped with temperature-controlled thermocouples (not shown in the figure) in the primary evaporation zone 1201, pressurization zone 1202, secondary evaporation zone 1203, and heating zone 1204 of the inner liner 12. The temperature-controlled thermocouples enable the primary evaporation zone 1201, pressurization zone 1202, secondary evaporation zone 1203, and heating zone 1204 to be heated and controlled separately, resulting in more precise temperature control and ensuring that the coating metal vapor is transported to the nozzle 2 in a saturated vapor pressure state.

[0060] Furthermore, in this embodiment, the linear metal evaporation source for vacuum coating has an arc-shaped longitudinal section in the primary evaporation zone 1201 of the inner liner 12 and a rectangular longitudinal section in the pressurization zone 1202 of the inner liner 12.

[0061] The inner liner 12 has an opening at the top of the primary evaporation zone 1201, which is connected to the pressurization zone 1202. The width of the pressurization zone 1202 is smaller than the diameter of the primary evaporation zone 1201. The arc-shaped primary evaporation zone 1201 allows the metal raw material to concentrate energy more during heating, reducing the loss of heating energy.

[0062] Furthermore, in this embodiment, the longitudinal section of the secondary evaporation zone 1203 of the inner liner 12 of the linear metal evaporation source for vacuum coating is conical.

[0063] The conical large end of the secondary evaporation zone 1203 of the inner liner 12 is positioned downwards and is connected to and communicates with the pressurization zone 1202. Within the secondary evaporation zone 1203, the coating metal vapor is further heated and compressed, resulting in a more uniform coating metal vapor.

[0064] Furthermore, in this embodiment, the linear metal evaporation source for vacuum coating has a rectangular longitudinal section for the heating zone 1204 of the inner liner 12, and the heating zone 1204 is connected and communicates with the conical small end of the secondary evaporation zone 1203.

[0065] Within the heating zone 1204 of the inner liner 12, the coating metal vapor is further heated to maintain the coating metal vapor at saturated vapor pressure and transported to the nozzle 2 to prevent the coating metal vapor from condensing within the nozzle 12.

[0066] Furthermore, in this embodiment, the vacuum coating linear metal evaporation source has a conical nozzle 2.

[0067] The large conical end of nozzle 2 is connected and communicates with the heating zone 1204 of inner liner 12, and the nozzle orifice 21 of nozzle 2 is located at the small conical end of nozzle 2.

[0068] In this embodiment, the nozzle is conical, which can effectively reduce the nozzle orifice size to reduce the heat dissipation in the pressurization zone. This reduces energy consumption and minimizes the amount of heat radiation from the evaporation source to the coated workpiece on the organic material substrate, thereby significantly improving the melting threshold of the coated workpiece on the organic material substrate.

[0069] Furthermore, in this embodiment, the linear metal evaporation source for vacuum coating is a ceramic fiber, and the heat insulation material 13 between the inner liner 12 and the metal outer cover 11 is ceramic fiber.

[0070] The linear metal evaporation source for vacuum coating of the present invention is set in the vacuum chamber of the coating production line. The metal raw material to be coated is heated and vaporized in the inner liner to reach saturated vapor pressure. The vapor jet is sprayed outward from the regular linear nozzle and deposited on the film substrate cooled and rotated by the cooling roller, or on the rigid material substrate moving in a straight line to form a uniform and dense metal film.

[0071] The metal raw material for coating in this invention can be copper, aluminum, zinc, etc., as needed, and the substrate (coating workpiece) material can be PET film, PP film, thin steel strip (thickness 0.05-1.5 mm), glass substrate, etc.

[0072] During use, the metal coating material is heated and liquefied within the inner liner; then the steam is transported a certain distance to the nozzle. During the transport process, the temperature along the transport path from the crucible to the nozzle increases at a certain rate, keeping the metal coating steam at saturated vapor pressure. Since there is a decrease in pressure and temperature of the steam between the nozzle and the substrate (coated workpiece), the nozzle is heated to appropriately raise the temperature of the steam, so as to achieve supersaturated deposition of the coating steam under suitable substrate temperature conditions, forming a uniform and dense film layer, and also preventing the steam from condensing at the nozzle.

[0073] In this invention, unless otherwise explicitly specified and limited, the first feature being "on" or "below" the second feature can mean that the first feature and the second feature are in direct contact, or that the first feature and the second feature are in indirect contact through an intermediate medium.

[0074] Furthermore, "above," "on top of," and "above" the first feature in relation to the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "under," and "beneath" the first feature in relation to the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0075] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A linear metal evaporation source for vacuum coating, characterized in that, include: Containers, nozzles, and crucibles; The container includes: a metal outer casing and an inner liner; The inner liner is disposed inside the metal outer cover, and the space between the inner liner and the metal outer cover is filled with heat-insulating material; The inner liner cavity comprises, from bottom to top: a primary evaporation zone, a pressurization zone, a secondary evaporation zone, and a heating zone; The cross-section of the primary evaporation zone is arc-shaped, and the cross-section of the pressurization zone is rectangular. The top opening of the primary evaporation zone is connected to the pressurization zone, and the width of the pressurization zone is smaller than the diameter of the primary evaporation zone; The cross-section of the secondary evaporation zone is conical; The large conical end of the secondary evaporation zone is connected to the pressurization zone; The heating zone has a rectangular cross-section and is connected to the conical small end of the secondary evaporation zone; The nozzle is conical; The large conical end of the nozzle is connected to the heating zone; The inner liner is made of graphite. The inner liner sidewalls of the primary evaporation zone, the pressurization zone, the secondary evaporation zone and the heating zone are electrically connected to an external power source to form a heater inside the container to heat the corresponding areas. The nozzle is made of graphite and is electrically connected to an external power source. The nozzle has a slit-shaped nozzle orifice and is located at the top of the inner liner, communicating with the heating zone; The crucible is placed in the primary evaporation zone and is used to hold the coating metal raw material; The linear metal evaporation source is located in the vacuum chamber of the vacuum coating equipment. The primary evaporation zone is used to heat the coating metal to vaporization. The pressurization zone, the secondary evaporation zone, and the heating zone are used to transport the coating metal vapor to the nozzle at saturated vapor pressure. The nozzle is used to eject the coating metal vapor in a linear jet to form a uniform and dense film layer on the coated workpiece.

2. The linear metal evaporation source for vacuum coating according to claim 1, characterized in that, Temperature control thermocouples are provided at the primary evaporation zone, the pressurization zone, the secondary evaporation zone, the heating zone, and the nozzle.

3. The linear metal evaporation source for vacuum coating according to claim 1, characterized in that, The heat insulation material is ceramic fiber.

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