Method and water vapor doping apparatus for water vapor doping in vacuum coating

Abstract

The application provides a method and a water vapor doping device for vacuum coating. The method can meet the requirement of small water vapor flow in the vacuum coating, is beneficial to the stability of the water partial pressure in the vacuum coating chamber, and is helpful to improve the stability of the vacuum coating process requiring water vapor doping. The method comprises the following steps: placing a water source in a first vacuum chamber and releasing water vapor from the water source; the vacuum coating is performed in a vacuum coating chamber, the vacuum coating chamber and the first vacuum chamber are communicated through a first communication pipe for conveying the water vapor, and a first adjusting valve is arranged on the first communication pipe; a water partial pressure detector is used to detect the water partial pressure in the vacuum coating chamber to obtain a water partial pressure detection value; a controller adjusts the opening degree of the first adjusting valve according to the comparison result of the water partial pressure detection value and a water partial pressure preset value; and the water source is selected from one or more of a crystalline hydrate and a molecular sieve adsorbing water vapor.

Description

Technical Field

[0001] This invention relates to vacuum coating technology, and particularly to a method and apparatus for water vapor doping in vacuum coating. Background Technology

[0002] In vacuum coating processes, especially in the preparation of semiconductor thin films using physical vapor deposition (PVD), a mass flow meter (MFC) is typically used to introduce water vapor generated from liquid water into the process chamber (i.e., the vacuum coating chamber). This method is characterized by stable and controllable flow rates. However, in practical use, the inventors found that a 10 sccm MFC cannot stably control flow rates ≤0.5 sccm. Under normal equipment conditions, changes in flow rate do not cause corresponding changes in vacuum level. This indicates that the actual gas flow rate entering the vacuum coating chamber using an MFC as a venting tool is unstable. Since the photoelectric properties of ITO (indium tin oxide) thin films are extremely sensitive to water vapor concentration and require only minimal amounts of water vapor (e.g., some processes require a water vapor flow rate of less than 1 sccm), existing water vapor doping methods using liquid water as the source and an MFC as the venting tool are prone to unstable control of the water vapor flow rate, resulting in large fluctuations and affecting production stability. Furthermore, when MFC control is unstable, the introduction of excessive water vapor can make the film deposited on the cathode baffle of the vacuum coating chamber more likely to fall off, increasing dust in the chamber and causing contamination of the coated products.

[0003] Chinese patent CN214736043U discloses a steam-circulating device for a coating equipment, primarily addressing the technical challenge of water vapor condensing during transport within pipelines, thus making it difficult to control the flow rate of water vapor entering the coating equipment. The device's main features include an insulation layer, heating wires, and a temperature sensor on the ventilation pipeline. These elements, along with a temperature controller on the power supply circuit, work together to control the temperature difference between the inside and outside of the ventilation pipeline, reducing water vapor condensation on the inner surface of the pipeline. The ventilation pipeline also includes a flow meter and valves to control the water vapor flow rate and the pipeline's opening and closing. The structure of this steam-circulating device is similar to that of a traditional steam generator used in vacuum coating equipment; the patent simply adds heating and temperature control devices to the ventilation pipeline, solving the problem of condensation in the ventilation pipeline of traditional steam generators by regulating the temperature difference between the inside and outside of the pipeline. The water vapor in this patent application is introduced via a gas mass flow meter. However, since the water source for traditional water vapor generators is liquid water, the vapor pressure of the water in the ventilation pipe is relatively high. When the temperature of the inner surface of the pipe reaches the dew point of the water vapor at this vapor pressure, condensation occurs. Therefore, the device provided by this patent cannot solve the problem of how to stably supply water vapor and reduce its impact on production stability when the water vapor flow rate is low.

[0004] Chinese patent application CN111293192A discloses a method for controlling water vapor in a vacuum chamber during the fabrication of a total organic carbon (TCO) film for solar cells. This patent application addresses the problem of poor accuracy in controlling low-flow water vapor using a mass flow meter (MFC). The method involves installing a cryogenic condenser pump in the transition chamber and / or process chamber of the TCO film fabrication equipment. The amount of water vapor in the transition chamber and / or process chamber is adjusted by intermittently turning the cryogenic condenser pump on and off. A residual gas analyzer (RGA) is also installed in the transition chamber and / or process chamber. When the RGA detects that the amount of water vapor in the chamber is greater than a set value, the cryogenic condenser pump is turned on; when the RGA detects that the amount of water vapor is less than the set value, the cryogenic condenser pump is turned off. However, the control method and response speed of the cryogenic pump's on / off state can cause some disturbance to the vacuum level and gas concentration in the vacuum chamber. Most importantly, the cryogenic pump, when turned on, not only adsorbs water vapor in the vacuum chamber but also other types of gases (Ar, O2, N2) in the chamber, which affects the stability of all process gases. This patent application does not offer a solution to this problem.

[0005] Chinese patent application CN104313542B discloses a method for preparing ITO (indium tin oxide) thin films, aiming to reduce the polycrystalline degree of ITO films and solve the problem of difficult etching of crystalline ITO. The method involves depositing an ITO thin film using magnetron sputtering. During the film deposition process, water vapor is introduced into the cavity via an MFC (Medium-Cellular Fusion Machine). The water vapor flow rate is calculated as Q² × T. ITO / 100000×(1±20%)sccm, Q2 is the Ar gas flow rate, T ITO The formula is used to calculate the water vapor flow rate under specific process conditions, given the thickness of the ITO film. However, this patent does not offer solutions to the problems of poor accuracy in controlling small water vapor flows using MFCs and the tendency for liquid water sources to condense. Summary of the Invention

[0006] This invention provides a method and apparatus for water vapor doping in vacuum coating. The method of this invention can meet the requirements of small water vapor flow in vacuum coating, which is beneficial to the stability of water pressure in the vacuum coating chamber and helps to improve the stability of vacuum coating processes that require water vapor doping.

[0007] To achieve its objective, the present invention provides the following technical solution:

[0008] This invention provides a method for water vapor doping in vacuum coating, the method comprising:

[0009] A water source is placed in a first vacuum chamber, and water vapor is released from the water source; the vacuum coating is performed in a vacuum coating chamber, and the vacuum coating chamber and the first vacuum chamber are connected by a first connecting pipe for conveying the water vapor, and a first regulating valve is provided on the first connecting pipe;

[0010] The moisture pressure in the vacuum coating chamber is detected by a moisture pressure detector to obtain the moisture pressure detection value; the controller adjusts the opening of the first regulating valve according to the comparison result between the moisture pressure detection value and the preset moisture pressure value.

[0011] The water source is selected from one or more of crystal hydrates and molecular sieves that have adsorbed water vapor.

[0012] In some embodiments, the moisture pressure detector is a residual gas analyzer, preferably with a detection limit of ≤1×10⁻⁶ for moisture pressure. -11 Torr.

[0013] In some embodiments, the first vacuum chamber is connected to a first pumping system, which enables the first vacuum chamber to reach a first preset vacuum level; preferably, the first preset vacuum level is ≤2E-5Torr.

[0014] Preferably, before the water vapor is introduced into the vacuum coating chamber from the first vacuum chamber, the vacuum level of the first vacuum chamber is controlled to a first preset vacuum level.

[0015] Preferably, the first vacuum chamber is further provided with a heating element capable of heating the water source.

[0016] In some embodiments, the method further includes:

[0017] Before placing the water source in the first vacuum chamber, the water source is stored in a storage chamber beforehand.

[0018] Preferably, the storage chamber is connected to a second vacuum system, which enables the storage chamber to reach a second preset vacuum level.

[0019] Preferably, the method further includes: during the storage of the water source in the storage room, ensuring that the vacuum degree of the storage room meets a second preset vacuum degree, wherein the second preset vacuum degree is preferably ≤5E-2Torr;

[0020] Preferably, the storage chamber is provided with a water source outlet, which is connected to the water source receiving port of the first vacuum chamber through a second connecting pipe. The second connecting pipe is provided with a second regulating valve. When it is necessary to send water to the first vacuum chamber, the second regulating valve is opened, and the water stored in the storage chamber is sent to the first vacuum chamber through the second connecting pipe.

[0021] Preferably, the crystalline hydrate is selected from one or more of CuSO4·5H2O, CaSO4·2H2O, and CH3COONa·3H2O; the molecular sieve is selected from 3A molecular sieve.

[0022] In some embodiments, the mass of the water source placed in the first vacuum chamber must be sufficient to meet the water pressure requirements for vacuum coating within the time required for the vacuum coating process.

[0023] The present invention also provides a water vapor doping device for implementing the method described above, the water vapor doping device comprising a first vacuum chamber, a first regulating valve, a first connecting pipe, a water pressure detector, and a controller;

[0024] The first vacuum chamber has a water source containing area for placing crystalline hydrates and / or molecular sieves that have adsorbed water vapor in its inner cavity. The first vacuum chamber has a water vapor outlet. The first connecting pipe is used to connect the water vapor outlet to the vacuum coating chamber of the vacuum coating device. The first connecting pipe is equipped with the first regulating valve.

[0025] The moisture pressure detector is used to detect the moisture pressure in the vacuum coating chamber to obtain the moisture pressure detection value. Preferably, the moisture pressure detector is a residual gas analyzer.

[0026] The controller is communicatively connected to the first regulating valve and the water pressure detector, and the controller can adjust the opening of the first regulating valve according to the comparison result of the water pressure detection value and the water pressure preset value.

[0027] In some embodiments, the water vapor doping device further includes a first pumping system, and the first vacuum chamber is connected to the first pumping system.

[0028] Preferably, the first vacuum chamber is further provided with a heating element capable of heating the crystalline hydrate and / or the water vapor molecular sieve placed in the first vacuum chamber.

[0029] In some embodiments, the water vapor doping device further includes a storage chamber, which is provided with a water source outlet. The water source outlet is connected to the water source receiving port of the first vacuum chamber through a second connecting pipe, and a second regulating valve is provided on the second connecting pipe.

[0030] Preferably, the water vapor doping device further includes a second extraction system, and the storage chamber is connected to the second extraction system.

[0031] In some embodiments, the water vapor doping device further includes a material conveying mechanism for conveying the crystalline hydrate and / or the molecular sieve adsorbed with water vapor in the storage chamber to the first vacuum chamber.

[0032] Preferably, the material conveying mechanism is a robotic arm.

[0033] The present invention also provides a vacuum coating apparatus, the vacuum coating apparatus comprising a vacuum coating device and the water vapor doping device described above, the vacuum coating device being provided with a vacuum coating chamber, and the water vapor outlet of the first vacuum chamber of the water vapor doping device being connected to the vacuum coating chamber of the vacuum coating apparatus through a first connecting pipe.

[0034] The technical solution provided by this invention has the following beneficial effects:

[0035] The method provided by this invention does not use liquid water as the water source, but instead uses crystalline hydrates and / or molecular sieves that have adsorbed water vapor. This water source can release trace amounts of water vapor at a very slow rate without condensation, making it easy to achieve stable water pressure control to meet minute water pressure requirements. In this method, a controller controls the first regulating valve, and adjusts the opening of the first regulating valve based on a comparison between the water pressure detected by the water pressure detector and a preset water pressure value for the vacuum coating chamber. This helps ensure the stability of the water pressure in the vacuum coating chamber. Furthermore, using this method, the pressure of other process gases in the vacuum coating chamber is not affected during water pressure adjustment, which is beneficial for achieving good process stability. Attached Figure Description

[0036] Figure 1 The diagram shown is a schematic of the water vapor doping device of the present invention configured on a vacuum coating equipment in one embodiment.

[0037] Figure 2 The figure shows a curve of the vacuum degree in the vacuum coating chamber changing over time when copper sulfate pentahydrate is used as the water source in one embodiment.

[0038] Explanation of some reference numerals in the attached drawings: First vacuum chamber 1, storage chamber 2, vacuum coating device 3, vacuum coating chamber 4, material conveying mechanism 5, moisture pressure detector 6, second vacuum pump 7, molecular pump 71, mechanical pump 72, first vacuum pump 8, molecular pump 81, mechanical pump 82, air extraction device 9, molecular pump 91, mechanical pump 92, second connecting pipe 10, second regulating valve 11, first connecting pipe 12, first regulating valve 13, container 14, water source placement area 15, first air extraction pipe 16, second air extraction pipe 17. Detailed Implementation

[0039] To facilitate understanding of the present invention, the following description, in conjunction with embodiments, will further illustrate the invention. It should be understood that the following embodiments are merely for a better understanding of the invention and do not imply that the invention is limited to these embodiments.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The term "and / or" may be used herein to include any and all combinations of one or more of the associated listed items.

[0041] Where specific experimental steps or conditions are not specified in the embodiments, the corresponding conventional experimental steps or conditions in this technical field can be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products. Terms such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] This invention provides a method for water vapor doping in vacuum coating, combined with... Figure 1 This method mainly includes:

[0043] A water source is placed in the first vacuum chamber 1, and water vapor is released from the water source in the first vacuum chamber 1;

[0044] Vacuum coating is performed in vacuum coating chamber 4; wherein, vacuum coating chamber 4 and first vacuum chamber 1 are connected by first connecting pipe 12, the first connecting pipe 12 is used to transport water vapor released from the water source in the first vacuum chamber 1, and the first connecting pipe 12 is provided with a first regulating valve 13 with adjustable opening; the water vapor released from the water source in the first vacuum chamber 1 enters vacuum coating chamber 4 through the first connecting pipe 12.

[0045] The moisture pressure inside the vacuum coating chamber 4 is detected by the moisture pressure detector 6 to obtain the moisture pressure detection value; the controller adjusts the opening of the first regulating valve 13 according to the comparison result between the moisture pressure detection value and the preset moisture pressure value, so that the amount of water vapor entering the vacuum coating chamber 4 from the first vacuum chamber 1 is regulated, so that the moisture pressure inside the vacuum coating chamber 4 is maintained at the required preset moisture pressure value.

[0046] The water source used is selected from one or more of crystal hydrates and molecular sieves that have adsorbed water vapor.

[0047] In the method of this invention, liquid water is not used as the water source; instead, crystalline hydrates and / or molecular sieves that have adsorbed water vapor are used. This water source differs significantly from liquid water. In a vacuum environment, this source (especially compared to liquid water) can release trace amounts of water vapor at a very slow rate, easily achieving stable control of water pressure to meet minute moisture pressure requirements. Furthermore, the released water vapor has extremely low vapor pressure in a vacuum environment, preventing condensation and droplet formation. In this method, a controller controls the first regulating valve, adjusting its opening based on a comparison between the moisture pressure detected by the moisture pressure detector and a preset moisture pressure value for the vacuum coating chamber. This helps ensure the stability of the moisture pressure within the vacuum coating chamber. Moreover, using this method, the pressure of other process gases within the vacuum coating chamber is not affected during moisture pressure adjustment, contributing to good process stability.

[0048] In a preferred embodiment, the moisture pressure detector is a residual gas analyzer (RGA), and preferably, the detection limit of the residual gas analyzer for moisture pressure is ≤1×10⁻⁶. -11 Torr, for example, 1×10 -11 Torr, 1×10 -12 Torr, 2×10 -12 Torr et al. used crystalline hydrates and / or molecular sieves that adsorbed water vapor as the water source, and employed Resonant Gas Observation (RGA) instead of Moisture Fiber Coating (MFC). The RGA detected the moisture pressure in the vacuum coating chamber, and the controller adjusted the opening of the first regulating valve based on the RGA reading. This method allows for more precise control of the water vapor content within the vacuum coating chamber, ensuring the stability of minute moisture pressures, improving control accuracy, and ultimately enhancing process stability.

[0049] Furthermore, the first vacuum chamber 1 is connected to a first pumping system, which enables the first vacuum chamber 1 to reach a first preset vacuum level. Specifically, the first pumping system may include a first vacuum pump 8 and a first pumping pipe 16. The first vacuum pump 8 is connected to the first vacuum chamber 1 via the first pumping pipe 16. By pumping vacuum with the first vacuum pump 8, the first vacuum chamber 1 can reach the required target vacuum level, i.e., the first preset vacuum level. The first vacuum pump 8 may specifically be a mechanical pump 82 and a molecular pump 81 connected in series, with the molecular pump 81 directly connected to the first vacuum chamber 1.

[0050] In some embodiments, the first vacuum chamber 1 may also be equipped with a heating element (not shown in the figure) capable of heating a water source placed within the first vacuum chamber 1. This allows for heating of the water source by the heating element (e.g., heating the water source within a temperature range of ≤100°C) when a higher water pressure is required, thereby increasing the steam release rate and meeting the requirements of vacuum coating processes with higher water pressure. The heating element can be, for example, an electric heating wire or an infrared lamp. The placement of the heating element is not particularly limited, as long as it effectively heats the water source. Specifically, for example, a heating wire can be placed in the water source containing area within the first vacuum chamber, and a heat-dampening plate made of copper, graphite, or stainless steel can be placed on the heating wire; alternatively, an infrared lamp can be placed above the water source containing area for radiant heating.

[0051] In a preferred embodiment, the method further includes: storing the water source in a storage chamber 2 before placing it in the first vacuum chamber 1. Preferably, the storage chamber 2 is also a vacuum chamber, connected to a second vacuum system. The second vacuum system enables the storage chamber 2 to reach a second preset vacuum level. Specifically, the second vacuum system may include a second vacuum pump 7 and a second vacuum pipe 17. The second vacuum pump 7 is connected to the storage chamber 2 through the second vacuum pipe 17. By evacuating the storage chamber 2 with the second vacuum pump 7, the storage chamber 2 can reach the required target vacuum level, i.e., the second preset vacuum level. The second vacuum pump 7 may specifically be a mechanical pump 72 and a molecular pump 71 connected in series, with the molecular pump 71 directly connected to the storage chamber 2. In a preferred embodiment, during the storage of the water source in the storage chamber 2, the vacuum level of the storage chamber 2 meets the second preset vacuum level, which is preferably ≤5E-2 Torr. Storing the water source at the preferred second preset vacuum level helps to reduce the release of water vapor from the water source during storage and reduce water vapor loss. More specifically, the storage chamber 2 is provided with a water source outlet (not shown in the figure), and the first vacuum chamber 1 is provided with a water source receiving port (not shown in the figure). The water source outlet is connected to the water source receiving port of the first vacuum chamber 1 through a second connecting pipe 10, and a second regulating valve 11 is provided on the second connecting pipe 10. In some embodiments, multiple portions of water can be pre-placed in the storage chamber 2, each portion being at least sufficient for the water quality required for one vacuum coating process. Thus, when multiple vacuum coating processes are performed, if the water source in the first vacuum chamber 1 can no longer release enough water vapor to meet the requirements, the water source in the storage chamber 2 can be replenished into the first vacuum chamber 1 through the second connecting pipe 10 by opening the second regulating valve 11, thereby eliminating the need for frequent external water replenishment and frequent disruption of the vacuum environment. More specifically, the water source in storage chamber 2 is transferred to the first vacuum chamber 1 via a material conveying mechanism 5, which can be, for example, a robotic arm. The robotic arm can be a conventional robotic arm with grasping and material transfer functions, and its configuration can be in accordance with conventional methods in the art, ensuring that the grasping part of the robotic arm can move between the storage chamber, the second connecting pipe, and the first vacuum chamber. The robotic arm is driven by an external power device. Preferably, the connection between the robotic arm and the storage chamber or the first vacuum chamber is sealed. Specifically, storage chamber 2 and the first vacuum chamber 1 can be provided with a water source placement area (or water source receiving area) 15, which can be a water source placement platform. In one specific embodiment, when it is necessary to send the water source in the storage chamber 2 into the first vacuum chamber 1, the second regulating valve 11 is opened, the gripping part of the robotic arm grabs the container 14 containing the water source in the storage chamber and sends it into the water source placement platform of the first vacuum chamber 1. After that, the gripping part of the robotic arm returns to the storage chamber 2, the second regulating valve 11 is closed, and the water source transfer operation is completed.

[0052] Specifically, the water source is placed in the first vacuum chamber 1 or storage chamber 2 in the form of a container 14 (e.g., a reagent dish), which can be a beaker or a container made of non-metallic materials such as ceramic.

[0053] Preferably, before introducing water vapor into the vacuum coating chamber 4, the vacuum degree of the first vacuum chamber 1 is controlled to a first preset vacuum degree. In some embodiments, when the storage chamber 2 is not present, water is directly obtained from the outside and placed into the first vacuum chamber 1 without passing through the storage chamber 2, and then the first vacuum chamber 1 is evacuated by the first evacuation system to reach the first preset vacuum degree; when the storage chamber 2 is present, the first vacuum chamber 1 is evacuated by the first evacuation system to reach the first preset vacuum degree before transferring the water from the storage chamber 2 to the first vacuum chamber 1. By adopting the above preferred method, impurity gases can be removed as much as possible, and the amount of impurity gases diffusing into the vacuum coating chamber 4 during subsequent vacuum coating can be reduced. In actual production, the above operation can be selected as needed based on process requirements or product requirements. In some embodiments, the first preset vacuum degree is, for example, ≤2E-5 Torr.

[0054] Preferably, the crystalline hydrate used as the water source meets the following conditions: 1. It has no other volatile components besides water of crystallization in a vacuum environment; 2. It is not a high-risk chemical (i.e., non-toxic and harmless), easy to store, and does not easily deliquesce in air. More preferably, in the method of the present invention, the crystalline hydrate used as the water source is one or more of the following crystals: CuSO4·5H2O, CaSO4·2H2O, CH3COONa·3H2O (sodium acetate trihydrate). More preferably, calcium chloride dihydrate is not used as the water source. Using the preferred crystalline hydrate as the water source in the method of the present invention can more stably meet the demand for small water vapor flow rates in vacuum coating, and can achieve better stability in vacuum coating processes that require water vapor doping. In the method of the present invention, using crystalline hydrate as the water source, the crystalline hydrate will undergo a certain degree of weathering after losing water in a vacuum environment. The weathered powder can be recrystallized in distilled water and recycled, avoiding waste and discharge of chemicals.

[0055] Preferably, the molecular sieve used as the water source is a molecular sieve that selectively adsorbs water vapor, preferably a 3A molecular sieve. The effective pore size of a 3A molecular sieve is approximately 3 angstroms, primarily adsorbing water vapor and having no adsorption effect on other molecules with diameters larger than 3 angstroms, ensuring that the gas released by the molecular sieve is pure water vapor. Using a molecular sieve as a water source allows for reuse through heating and regeneration. For example, the 3A molecular sieve can be used for water vapor adsorption using the following steps: 1. Regenerate the 3A molecular sieve to remove adsorbed water molecules; 2. Adsorb water vapor onto the molecular sieve at room temperature and in an environment with a humidity of 70%-80%, allowing water vapor to be adsorbed inside the molecular sieve; After completing the above operations, a 3A molecular sieve adsorbing water vapor is obtained and used as a water source.

[0056] In some embodiments, the method of the present invention specifically includes the following steps:

[0057] S1: Determine the mass M of water required to maintain the preset water pressure value of the vacuum coating chamber 4 within the time required for vacuum coating (e.g., the time required for sputtering deposition);

[0058] S2: Place at least one portion of water of mass M into storage chamber 2, turn on the second vacuum system, and maintain the vacuum level of storage chamber 2 at a second preset vacuum level, preferably within the range of ≤5E-2Torr;

[0059] S3: Open the second regulating valve 11 and transfer the water source of mass M from the storage chamber 2 to the first vacuum chamber 1 through the material conveying mechanism 5; preferably, before water vapor is introduced into the vacuum coating chamber 4 from the first vacuum chamber 1, the vacuum degree of the first vacuum chamber 1 is controlled to the first preset vacuum degree (preferably ≤2E-5Torr).

[0060] S4: The moisture pressure detector 6 (RGA) is turned on to detect the moisture pressure in the vacuum coating chamber 4. The controller adjusts the opening of the first regulating valve 13 according to the comparison result between the moisture pressure detection value obtained by the RGA and the preset moisture pressure value, so that the moisture pressure in the vacuum coating chamber 4 is maintained at the preset moisture pressure value.

[0061] S5: Vacuum coating is performed after the moisture pressure in the vacuum coating chamber 4 is maintained at the preset moisture pressure value.

[0062] In some embodiments, the mass M of water required to maintain the preset moisture pressure in the vacuum coating chamber within the time required for vacuum coating, as mentioned in step S1, can be determined by the following steps:

[0063] S1-1: Determine the time required for vacuum coating in the vacuum coating chamber 4 equipped with the air extraction device 9 and the required preset value of moisture pressure.

[0064] S1-2: Place a water source of mass X into the first vacuum chamber 1, keep the first regulating valve 13 fully open, and at the same time turn on the air extraction device 9 of the vacuum coating chamber 4 to continuously extract air and monitor the real-time water pressure in the vacuum coating chamber 4.

[0065] S1-3: Obtain the duration during which the real-time moisture pressure is greater than or equal to (preferably greater than) the preset moisture pressure value. When the duration is greater than or equal to (preferably greater than) the time required for vacuum coating, the mass M is considered to be mass X.

[0066] Preset parameters such as moisture pressure can be set according to the different requirements of the vacuum coating process or the target product. The specific vacuum coating process can be determined based on the specific vacuum coating process requirements and can be performed using conventional vacuum coating operations in this field, which will not be elaborated upon here.

[0067] The method of this invention can effectively meet the moisture pressure requirements (e.g., a typical moisture pressure of 10) during the sputtering deposition process of TCO thin films (transparent conductive films). -6 Torr to 10 -8 The requirement for TCO (Tolerance between Torr) enables more direct and precise control of moisture pressure, especially minute moisture pressure, which is beneficial for improving process stability. TCO films include, but are not limited to, indium tin oxide, indium cerium oxide, indium molybdenum oxide, and aluminum-doped zinc oxide.

[0068] The "vacuum coating" mentioned in this invention can be physical vapor deposition coating.

[0069] A second aspect of the invention also provides a water vapor doping apparatus for implementing the method described above. See also Figure 1 The water vapor doping device mainly includes a first vacuum chamber 1, a first regulating valve 13, a first connecting pipe 12, a water pressure detector 6, and a controller (not shown in the figure).

[0070] The first vacuum chamber 1 has a water source containing area 15 for placing water (specifically, crystalline hydrates and / or molecular sieves that adsorb water vapor) in its inner cavity. The first vacuum chamber 1 has a water vapor outlet (not shown in the figure). The first connecting pipe 12 is used to connect the water vapor outlet of the first vacuum chamber 1 to the vacuum coating chamber 4 of the vacuum coating device 3. The first connecting pipe 12 is equipped with a first regulating valve 13.

[0071] The moisture pressure detector 6 is used to detect the moisture pressure in the vacuum coating chamber to obtain the moisture pressure detection value. The moisture pressure detector is preferably a residual gas analyzer (RGA).

[0072] The controller is communicatively connected to the first regulating valve 13 and the moisture pressure detector 6. The controller adjusts the opening of the first regulating valve 13 based on a comparison between the detected moisture pressure value and a preset moisture pressure value. This regulates the amount of water vapor entering the vacuum coating chamber 4 from the first vacuum chamber 1 via the first connecting pipe 12, thereby maintaining the moisture pressure in the vacuum coating chamber 4 at the desired preset moisture pressure value. The controller used can be a conventional controller with corresponding calculation, analysis, and control functions, such as a pressure controller.

[0073] Furthermore, the water vapor doping device also includes a first pumping system, with the first vacuum chamber 1 connected to the first pumping system. Specifically, the first pumping system includes a first vacuum pump 8 and a first pumping pipe 16. The first vacuum pump 8 is connected to the first vacuum chamber 1 via the first pumping pipe 16. Pumping a vacuum with the first vacuum pump 8 enables the first vacuum chamber 1 to reach the desired target vacuum level, such as a first preset vacuum level. The first vacuum pump 8 can specifically be a mechanical pump 82 and a molecular pump 81 connected in series, with the molecular pump 81 directly connected to the first vacuum chamber 1.

[0074] Furthermore, the first vacuum chamber 1 may be equipped with a heating element capable of heating a water source placed within the first vacuum chamber. The heating element may be, for example, an electric heating wire or an infrared lamp. There are no particular restrictions on the placement of the heating element, as long as it can achieve the function of heating the water source. A description of the heating element can be found in the preceding text and will not be repeated here.

[0075] Furthermore, the water vapor doping device also includes a storage chamber 2, which has a water source outlet (not shown in the figure). The water source outlet is connected to the water source receiving port (not shown in the figure) of the first vacuum chamber 1 via a second connecting pipe 10. A second regulating valve 11 is provided on the second connecting pipe 10. When it is necessary to transfer water from the storage chamber 2 to the first vacuum chamber 1, the second regulating valve 11 is opened. Furthermore, the water vapor doping device also includes a second pumping system, which is connected to the storage chamber 2. Specifically, the second pumping system includes a second vacuum pump 7 and a second pumping pipe 17. The second vacuum pump 7 is connected to the storage chamber 2 via the second pumping pipe 17. By pumping vacuum with the second vacuum pump 7, the storage chamber 2 can reach the required target vacuum level, such as a second preset vacuum level. The second vacuum pump 7 can specifically be a mechanical pump 72 and a molecular pump 71 connected in series, with the molecular pump 71 directly connected to the storage chamber 2.

[0076] Furthermore, the water vapor doping device also includes a material conveying mechanism 5 for conveying water from the storage chamber 2 to the first vacuum chamber 1. The material conveying mechanism is, for example, but not limited to, a robotic arm. The description of the material conveying mechanism can be found in the previous description and will not be repeated here.

[0077] Specifically, the first regulating valve 13 can be a gate valve or a butterfly valve, etc., and the second regulating valve 11 can be a gate valve, etc.

[0078] This invention also provides a vacuum coating apparatus, see [link to relevant documentation]. Figure 1 The vacuum coating equipment includes a vacuum coating device 3 and the water vapor doping device described above. The vacuum coating device 3 is equipped with a vacuum coating chamber 4. The water vapor outlet of the first vacuum chamber 1 of the water vapor doping device is connected to the vacuum coating chamber 4 of the vacuum coating device 3 via a first connecting pipe 12. For a detailed description of the water vapor doping device, please refer to the preceding text; it will not be repeated here. One of the main improvements of this invention is the addition of a water vapor doping device to the vacuum coating device. The vacuum coating device can be any device in the art capable of meeting the requirements of vacuum coating, such as conventional vacuum coating devices already existing in the art; this will not be elaborated upon. The vacuum coating device is equipped with a pumping device 9, specifically including, for example, a molecular pump 91 connected to the vacuum coating chamber 4, and a mechanical pump 92 connected in series with the molecular pump 91.

[0079] The method of the present invention will be illustrated by specific embodiments below.

[0080] Example 1:

[0081] In this embodiment, CuSO4·5H2O hydrate was used as the water source. A 120 nm ITO thin film was deposited on a glass substrate using magnetron sputtering. The preset water pressure in the vacuum deposition chamber was 5E-7 Torr, and the sputtering deposition time was 45 min. The sheet resistivity of the ITO thin film was measured using a four-probe resistance meter. The water vapor doping apparatus used is described in [reference needed]. Figure 1 The structural description of the water vapor doping device is provided above and will not be repeated here. The water vapor pressure detector used is a residual gas analyzer (using Hiden Analytical's RGA, detection limit ≥2×10⁻⁶). -12 (Tor). The first regulating valve 13 is a butterfly valve with adjustable opening, and the second regulating valve 11 is a gate valve. The first vacuum pump 8 consists of a molecular pump 81 and a mechanical pump 82 connected in series, and the second vacuum pump 7 consists of a molecular pump 71 and a mechanical pump 72 connected in series. The vacuum coating device 3 is equipped with a pumping device 9, which specifically includes a molecular pump 91 and a mechanical pump 92 connected in series, wherein the molecular pump 91 is connected to the vacuum coating chamber 4.

[0082] The experimental procedure is as follows:

[0083] 1) Determine the mass M of water required to maintain the preset moisture pressure in the vacuum coating chamber during the sputtering deposition time for vacuum coating:

[0084] Weigh a certain mass of copper sulfate pentahydrate using an analytical balance and place it in a beaker;

[0085] M1 = M CuSO4·5H2O =3.2937g

[0086] M2 = M CuSO4·5H2O+烧杯 =11.8073g

[0087] First, place the beaker in the storage chamber and evacuate it to a vacuum level of 5E-4 Torr using the second vacuum pump. Then, evacuate the first vacuum chamber to a vacuum level of 2E-5 Torr using the first vacuum pump. Next, open the gate valve (i.e., the second regulating valve) and use a robotic arm to transfer the beaker containing CuSO4·5H2O into the first vacuum chamber, then close the gate valve. When the pressure in the vacuum coating chamber reaches 4E-8 Torr (this is the background vacuum), fully open the first regulating valve and continuously evacuate the vacuum coating chamber using the evacuation device 9. Observe and record the change in pressure in the vacuum coating chamber as the water of crystallization in copper sulfate pentahydrate is released. The obtained curves are shown in [reference needed]. Figure 2 .

[0088] from Figure 2 As can be seen, after opening the first regulating valve, the gas pressure in the vacuum coating chamber rapidly increased from 4E-8 Torr (background vacuum) to 1.3E-5 Torr. Continuous observation of the gas pressure changes in the coating equipment revealed that, due to the decreasing release rate of water of crystallization from anhydrous copper sulfate over time, the gas pressure in the vacuum coating chamber also continuously decreased. After evacuating the vacuum coating chamber for 140 hours, the gas pressure dropped to approximately 5E-8 Torr (measured by a high vacuum gauge), close to (on the same order of magnitude) the background vacuum of the vacuum coating chamber. This indicates that the amount of water vapor released by the hydrated crystals has a very small, almost negligible, effect on the vacuum level. The beaker was then removed and weighed using an analytical balance.

[0089] M3 = M CuSO4·5H2O+烧杯 =10.7565g

[0090] The total mass of water of crystallization released is:

[0091] △M=M2-M3=1.0508g

[0092] Assuming the final chemical formula of copper sulfate is CuSO4·xH2O, using the above data, we can calculate that x≈0.6. Therefore, after 140 hours of evacuation, 3.2937g of CuSO4·5H2O is converted to CuSO4·0.6H2O, releasing 1.0508g of water of crystallization. This demonstrates that the rate of water vapor release within 140 hours is extremely small and gradual. Figure 2From the pressure change curve of the vacuum coating chamber, the pressure in the vacuum coating chamber minus the background vacuum is the moisture pressure. The duration of this moisture pressure being greater than the preset moisture pressure value (i.e., 5E-7 Torr) is much longer than the sputtering deposition time of vacuum coating (i.e., 45 min). Therefore, it can be seen that the water vapor release from 3.2937g of copper sulfate pentahydrate is sufficient to meet the process requirements of this coating equipment for depositing ITO thin films. Thus, the mass M of a water source is determined to be 3.2937g.

[0093] 2) Place one portion (3.2937 g) of CuSO4·5H2O crystals in a beaker into the storage chamber (multiple portions (M) of CuSO4·5H2O crystals can be placed in the storage chamber as needed). Turn on the second vacuum pump and evacuate to a vacuum level of 5E-4 Torr. Use the first vacuum pump to evacuate the first vacuum chamber to a vacuum level of 2E-5 Torr.

[0094] 3) Open the gate valve (i.e. the second regulating valve), use a robotic arm to transfer the beaker containing mass M of CuSO4·5H2O to the first vacuum chamber, and close the gate valve.

[0095] 4) Turn on RGA to detect the moisture pressure in the vacuum coating chamber. The controller adjusts the opening of the first regulating valve according to the comparison result between the moisture pressure detection value obtained by RGA and the preset moisture pressure value (5E-7Torr in this embodiment). That is, when the moisture pressure detection value is lower than the preset moisture pressure value, the opening of the first regulating valve is increased, and vice versa.

[0096] 5) When the moisture pressure in the vacuum coating chamber is maintained at the preset value and no longer fluctuates, vacuum coating is performed. Specifically, the target material composition is indium tin oxide (In2O3:SnO2 = 95:5wt%). Ar is introduced into the vacuum coating chamber at a flow rate of 20 sccm. The power supply is set to 50W. During the vacuum film deposition process, the vacuum coating chamber is continuously evacuated by the pumping device 9 to maintain the total gas pressure in the vacuum coating chamber at 3 mTorr. The sputtering deposition time is 45 minutes.

[0097] After the ITO thin film was prepared, the film thickness was measured using a profilometer, and the sheet resistivity of the ITO thin film was measured using a four-probe method. The results were 125 nm and [missing data]. The resistivity is 2.95E-4Ω·cm.

[0098] Vacuum deposition is performed as described in step 5) above, except that water vapor is not introduced into the vacuum deposition chamber, resulting in an increase in the sheet resistivity of the obtained ITO film.

[0099] Example 2

[0100] The experiment was repeated four times (corresponding to experiments 1#-4# in Table 1 below) following steps 2)-5) of Example 1. The sheet resistance, film thickness and resistivity of the obtained ITO film are shown in Table 1 below.

[0101] Table 1

[0102] Experiment number Surface resistance / Ω / □ Film thickness / nm resistivity / Ω.cm 1# 24.57 124 3.05E-4 2# 23.31 129 3.01E-4 3# 23.24 129 3.00E-4 4# 23.25 128 2.98E-4

[0103] The experimental results from Examples 1 and 2 show that, under the same process conditions, the ITO thin film exhibits excellent repeatability in terms of sheet resistivity, film thickness, and resistivity after multiple experiments. Furthermore, it demonstrates excellent process stability even under minimal moisture pressure requirements. Therefore, the method of this invention can incorporate trace amounts of water vapor into vacuum deposition processes to meet minimal moisture pressure requirements, ensuring stable moisture pressure in the vacuum deposition chamber and improving the stability of vacuum deposition processes requiring water vapor incorporation.

[0104] It is readily understood that the above embodiments are merely illustrative examples for clear explanation and do not imply that the invention is limited thereto. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for water vapor doping in vacuum coating, characterized in that, The method includes: A water source is placed in a first vacuum chamber, and water vapor is released from the water source; the vacuum coating is performed in a vacuum coating chamber, and the vacuum coating chamber and the first vacuum chamber are connected by a first connecting pipe for conveying the water vapor, and a first regulating valve is provided on the first connecting pipe; The moisture pressure in the vacuum coating chamber is detected by a moisture pressure detector to obtain the moisture pressure detection value; the controller adjusts the opening of the first regulating valve according to the comparison result between the moisture pressure detection value and the preset moisture pressure value. The water source is selected from one or more of crystal hydrates and molecular sieves that have adsorbed water vapor.

2. The method according to claim 1, characterized in that, The moisture pressure detector is a residual gas analyzer.

3. The method according to claim 2, characterized in that, The residual gas analyzer has a detection limit of ≤1×10⁻⁶ for water pressure. -11 Torr.

4. The method according to claim 1, characterized in that, The first vacuum chamber is connected to a first pumping system, which enables the first vacuum chamber to reach a first preset vacuum level.

5. The method according to claim 4, characterized in that, The first preset vacuum degree is ≤2E-5Torr.

6. The method according to claim 4, characterized in that, Before the water vapor is introduced into the vacuum coating chamber from the first vacuum chamber, the vacuum level of the first vacuum chamber is controlled to a first preset vacuum level.

7. The method according to claim 4, characterized in that, The first vacuum chamber is also equipped with a heating element capable of heating the water source.

8. The method according to claim 4, characterized in that, The method further includes: Before placing the water source in the first vacuum chamber, the water source is stored in a storage chamber beforehand.

9. The method according to claim 8, characterized in that, The storage chamber is connected to a second vacuum system, which enables the storage chamber to reach a second preset vacuum level.

10. The method according to claim 8, characterized in that, The method further includes: during the storage of the water source in the storage chamber, ensuring that the vacuum level of the storage chamber meets a second preset vacuum level.

11. The method according to claim 10, characterized in that, The second preset vacuum degree is ≤5E-2Torr.

12. The method according to claim 8, characterized in that, The storage chamber is provided with a water source outlet, which is connected to the water source receiving port of the first vacuum chamber through a second connecting pipe. The second connecting pipe is provided with a second regulating valve. When it is necessary to send water to the first vacuum chamber, the second regulating valve is opened, and the water stored in the storage chamber is sent to the first vacuum chamber through the second connecting pipe.

13. The method according to any one of claims 1-3, characterized in that, The crystalline hydrate is selected from one or more of CuSO4·5H2O, CaSO4·2H2O, and CH3COONa·3H2O; the molecular sieve is selected from 3A molecular sieve.

14. The method according to any one of claims 1-7, characterized in that, The mass of the water source placed in the first vacuum chamber must be sufficient to meet the water pressure requirements for vacuum coating within the time required.

15. A water vapor doping apparatus for carrying out the method of claim 1, characterized in that, The water vapor doping device includes a first vacuum chamber, a first regulating valve, a first connecting pipe, a water pressure detector, and a controller; The first vacuum chamber has a water source containing area for placing crystalline hydrates and / or molecular sieves that have adsorbed water vapor in its inner cavity. The first vacuum chamber has a water vapor outlet. The first connecting pipe is used to connect the water vapor outlet to the vacuum coating chamber of the vacuum coating device. The first connecting pipe is equipped with the first regulating valve. The moisture pressure detector is used to detect the moisture pressure in the vacuum coating chamber to obtain the moisture pressure detection value; The controller is communicatively connected to the first regulating valve and the water pressure detector, and the controller can adjust the opening of the first regulating valve according to the comparison result of the water pressure detection value and the water pressure preset value.

16. The water vapor doping device according to claim 15, characterized in that, The moisture pressure detector is a residual gas analyzer.

17. The water vapor doping device according to claim 15, characterized in that, The water vapor doping device further includes a first pumping system, and the first vacuum chamber is connected to the first pumping system.

18. The water vapor doping device according to claim 17, characterized in that, The first vacuum chamber is also provided with a heating element capable of heating the crystalline hydrate and / or the molecular sieve that has adsorbed water vapor placed in the first vacuum chamber.

19. The water vapor doping device according to claim 15, characterized in that, The water vapor doping device also includes a storage chamber, which is provided with a water source outlet. The water source outlet is connected to the water source receiving port of the first vacuum chamber through a second connecting pipe, and a second regulating valve is provided on the second connecting pipe.

20. The water vapor doping device according to claim 19, characterized in that, The water vapor doping device also includes a second extraction system, and the storage chamber is connected to the second extraction system.

21. The water vapor doping device according to claim 19, characterized in that, The water vapor doping device also includes a material conveying mechanism for conveying the crystalline hydrates and / or molecular sieves adsorbed with water vapor in the storage chamber to the first vacuum chamber.

22. The water vapor doping device according to claim 21, characterized in that, The material conveying mechanism is a robotic arm.

23. A vacuum coating apparatus, characterized in that, The vacuum coating equipment includes a vacuum coating apparatus and a water vapor doping apparatus as described in any one of claims 15-22. The vacuum coating apparatus is provided with a vacuum coating chamber, and the water vapor outlet of the first vacuum chamber of the water vapor doping apparatus is connected to the vacuum coating chamber of the vacuum coating apparatus through the first connecting pipe.

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