Multi-station optical filter surface coating device and method thereof

Abstract

The invention relates to a multi-station optical filter surface coating device and a method thereof, and belongs to the technical field of coating devices.The method comprises the steps that a magnetic suspension conveying system, a sputtering system and a dynamic air curtain isolation system are arranged in a single tunnel type main vacuum chamber, the magnetic suspension transport system comprises a linear driving coil mounted outside the cavity, a magnetic suspension tray arranged inside the cavity and used for bearing a substrate, and a position detection unit mounted outside the cavity, and the tray and the coil realize magnetic field coupling through the cavity wall; the sputtering system comprises a plurality of sputtering target materials which are sequentially mounted on the inner top wall of the cavity, and the core progress of the invention is that a set of magnetic suspension transportation system is adopted, so that the problem of particle pollution is solved; the system is characterized in that the linear driving coil is arranged outside the cavity, the magnetic suspension tray for bearing the substrate is contained in the cavity, no mechanical connection exists between the linear driving coil and the magnetic suspension tray, and magnetic field coupling is achieved only through the non-magnetic cavity wall.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coating device, in particular to a multi-station filter surface coating device and method thereof. BACKGROUND

[0002] In the field of optical elements, semiconductors and display panel manufacturing, high-precision thin film deposition is a core process. Especially for the production of multi-layer optical filters, it is often necessary to alternately deposit dozens or even hundreds of layers of materials with different refractive indices, such as silicon dioxide and tantalum pentoxide; the existing coating technology mainly faces the following challenges:

[0003] Batch production, box-type machine: using a box-type coating machine for production, although the equipment cost is low, but each time the cavity door is opened, it will introduce pollution, and the substrate loading and unloading time is long, it is impossible to realize continuous flow production, the overall efficiency is low.

[0004] High-cost solution, multi-chamber connection: using a multi-chamber connection system, each chamber processes one kind of material, and the transmission between chambers is realized through a vacuum manipulator and a gate. Although this solution can effectively isolate pollution, the system is extremely complex, and the equipment investment cost and vacuum maintenance cost are extremely high.

[0005] Transmission pollution and stability problems: whether it is the large planetary transmission of the box-type machine or the mechanical arm of the multi-chamber, all mechanical transmission parts such as bearings, gears, and joints in the ultra-high vacuum environment will generate tiny particles when running due to friction; once these particles adhere to the surface of the optical substrate, they will cause coating defects.

[0006] Cross-contamination problem: when multiple materials are sputtered in a single chamber, sputtered atoms in different stations will diffuse with each other, resulting in impure film layers, i.e. cross-contamination; using a simple mechanical baffle is difficult to effectively isolate, and the baffle itself can also become a source of pollution.

[0007] Therefore, the industry urgently needs a new type of coating device that must meet the needs of high throughput, low cost, high cleanliness and high purity. This solution aims to solve two core technical problems: (1) particle pollution caused by mechanical friction in the vacuum chamber; (2) cross-contamination caused by atomic diffusion when multiple stations are running in a single chamber.

[0008] The above information disclosed in the above background section is only used to strengthen the understanding of the background of the present disclosure, therefore it can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0009] The purpose of the present application is to provide a multi-station filter surface coating device and method thereof to solve the problems raised in the above background.

[0010] The technical scheme of the present application is as follows:

[0011] S1, a magnetic levitation transportation system, a sputtering system and a dynamic air curtain isolation system are arranged in a single tunnel type main vacuum chamber, wherein the magnetic levitation transportation system comprises a linear drive coil mounted outside the chamber, a magnetic levitation tray arranged inside the chamber for carrying a substrate, and a position detection unit mounted outside the chamber, the tray and the coil being magnetically coupled through the chamber wall;

[0012] The sputtering system comprises a plurality of sputtering targets mounted in sequence on the inner top wall of the chamber;

[0013] The dynamic air curtain isolation system comprises a physical baffle fixedly mounted on the inner top wall and located between every two adjacent sputtering targets, and the physical baffle is connected with an isolation vacuum pump;

[0014] S2, the substrate is placed on the magnetic levitation tray, and the single tunnel type main vacuum chamber is pumped to a background vacuum better than 1x10⁻ 4 Pa;

[0015] S3, the linear drive coil is excited by the control system to make the magnetic levitation tray realize non-contact active suspension, and is pushed to the lower side of the sputtering target in the "start-stop" mode;

[0016] S4, when the tray reaches the lower side of any sputtering target, the control system performs closed-loop positioning,

[0017] Wherein, the closed-loop positioning comprises: detecting the actual position of the tray by the position detection unit; comparing the actual position with the preset target position to calculate the position deviation; dynamically adjusting the current of the linear drive coil according to the position deviation to generate a correcting magnetic force, so that the tray realizes magnetic force locking and accurate hovering;

[0018] The closed-loop positioning logic processing flow is as follows:

[0019] Input source: the input of this flow is the original position signal of the position detection unit, such as the Hall sensor array, installed outside the chamber, and the preset target hovering position data stored in the control system, i.e. the center point position of each sputtering target.

[0020] Step 1, position detection: the control system receives the real-time position signal sent by the Hall sensor array and processes it to convert it into the actual position coordinates of the tray.

[0021] Step 2, deviation calculation: the control system compares the actual position coordinates obtained at present with the preset target position coordinates of the target position, and calculates the position deviation, .

[0022] Logic Step 3, Corrective Magnetic Force Generation: The control system dynamically adjusts the current of the linear drive coils around the target position according to the calculated positional deviation. The adjustment magnitude of the current is proportional to the positional deviation and in the opposite direction, thus generating a fine corrective magnetic force in the opposite direction of the deviation.

[0023] Logic Step 4, Magnetic Force Locking: This corrective magnetic force actively pulls the tray back to the target point, forming a high-rigidity magnetic force locking state, allowing the tray to hover precisely above the center point of the sputtering target with a positioning accuracy of less than .

[0024] Output Result and Flow Direction: The final output of the process is the magnetic force locking state, which serves as the logical condition for the start of the next film deposition process S5, ensuring that the tray has reached and maintained the required precise position before the film deposition process begins;

[0025] S5, During the hovering of the tray, the corresponding sputtering target is started for film deposition, and the isolation vacuum pump in the dynamic gas curtain isolation system is started. The isolation vacuum pump creates a transverse pressure gradient in the isolation space formed by the physical baffle and the tray, actively extracting diffused contaminant atoms to prevent cross-contamination;

[0026] S6, After the current work station completes film deposition, the control system moves the tray frictionlessly to the next sputtering target and repeats steps S4 and S5 until the deposition of the multi-layer film system is completed.

[0027] Preferably, in step S3, the non-contact active suspension includes: real-time monitoring of the gap between the tray and the bottom of the chamber by the gap sensor, and the control system adjusts the current of the suspension electromagnet according to the gap to keep the tray at a suspension height of 1-3mm.

[0028] Preferably, in step S4, the magnetic force locking allows the tray to hover above the center point of the sputtering target with a positioning accuracy of less than 0.5mm.

[0029] Preferably, the isolation vacuum pump is a turbo molecular pump.

[0030] Preferably, the position detection unit is an array of Hall sensors.

[0031] Preferably, the plurality of sputtering targets includes a first target for depositing silicon dioxide and a second target for depositing tantalum pentoxide, and the method deposits a multi-layer optical film system by alternately repeating steps S4 and S5 between the first target and the second target.

[0032] A multi-station filter surface film deposition device, comprising:

[0033] a single tunnel-shaped main vacuum chamber;

[0034] a magnetic levitation transport system,

[0035] The magnetic levitation transport system comprises a linear drive coil installed outside the chamber, a magnetic levitation tray arranged inside the chamber for carrying the substrate, and a position detection unit installed outside the chamber.

[0036] The tray and the coil are coupled by a magnetic field through the chamber wall.

[0037] A sputtering system, the sputtering system comprising a plurality of sputtering targets installed in sequence on the inner top wall of the chamber;

[0038] A dynamic air curtain isolation system, the dynamic air curtain isolation system comprising a physical baffle fixedly installed on the inner top wall and located between every two adjacent sputtering targets, the physical baffle being connected with an isolation vacuum pump;

[0039] A control system, the control system being connected with the position detection unit and the linear drive coil,

[0040] The control system is configured to:

[0041] The linear drive coil is excited to enable the magnetic levitation tray to realize non-contact active suspension and start-stop mode propulsion.

[0042] When the tray reaches below any sputtering target, closed-loop positioning is performed, which comprises calculating a position deviation according to a detection signal of the position detection unit and a preset target position, and generating a correction magnetic force to enable the tray to realize magnetic force locking and accurate hovering.

[0043] During the hovering of the tray, the corresponding sputtering target is started, and the isolation vacuum pump is started.

[0044] Preferably, the magnetic levitation transport system further comprises a gap sensor, and the control system is further configured to adjust the current of the levitation electromagnet according to the signal of the gap sensor to keep the tray at a suspension height of 1-3mm.

[0045] Preferably, the control system is configured to enable the tray to hover with a positioning accuracy of less than 0.5mm.

[0046] Preferably, the isolation vacuum pump is a turbo molecular pump, and the position detection unit is a Hall sensor array.

[0047] The present application provides a multi-station filter surface coating device and method, which has the following improvements and advantages compared with the prior art.

[0048] 1. The core progress of this scheme is to adopt a set of magnetic levitation transport system to solve the problem of particulate pollution; The ingenious part of this system is that the linear drive coil is arranged outside the chamber, and the magnetic levitation tray carrying the substrate is contained in the chamber, and there is no mechanical connection between the two, and only the non-magnetic chamber wall realizes the magnetic field coupling; The control system excites the external coil, so that the internal tray realizes non-contact active suspension in the vacuum environment, such as maintaining a suspension height of 1-3mm and frictionless movement; This design completely eliminates all mechanical friction components inside the vacuum chamber, so that the source of particulate generation no longer exists, thereby ensuring a high-purity coating environment;

[0049] 2. Another key progress of this scheme is to efficiently solve the cross-contamination problem through a dynamic air curtain isolation system; The system is fixedly installed with physical baffles between every two adjacent sputtering targets on the inner top wall, and independent isolation vacuum pumps such as turbo molecular pumps are connected to these baffles; When the tray is accurately hovering for coating at any work station, the adjacent isolation vacuum pump is started synchronously; The isolation pump creates a strong transverse pressure gradient, i.e. a local low-pressure trap, in the narrow isolation space formed between the physical baffles and the tray without contact; This pressure gradient forces any contamination atoms trying to diffuse from one side to the other to be actively extracted and pumped away at high speed, so that they cannot reach the adjacent work station, thereby ensuring the high purity of the deposited film layer by using the principle of fluid dynamics;

[0050] 3. The overall beneficial effect of this scheme is that it realizes the cooperative work of the above two systems in a single tunnel-shaped main vacuum chamber structure; In order to match the start-stop mode required for multi-layer film deposition, the control system is configured to perform high-precision closed-loop positioning; The position detection unit installed outside the chamber, such as a Hall sensor array, monitors the actual position of the tray in real time, and the control system compares it with the preset target position, instantaneously calculates the position deviation, and dynamically adjusts the coil current to generate accurate correction magnetic force; This magnetic force locking mechanism ensures that the tray can accurately hover below the target material with extremely high precision, such as a positioning accuracy of less than 0.5mm, ensuring the uniformity of film growth. BRIEF DESCRIPTION OF DRAWINGS

[0051] The application will be further explained in conjunction with the drawings and examples:

[0052] Figure 1 is the schematic diagram of the external overall structure of the device;

[0053] Figure 2 is the schematic diagram of the cross-sectional structure of the single tunnel-shaped main vacuum chamber;

[0054] Figure 3 is the schematic diagram of the structure of the magnetic levitation tray;

[0055] Figure 4 is a schematic diagram of the process flow structure of the present application.

[0056] In the figure: 100, a single tunnel main vacuum chamber; 110, inner top wall; 200, magnetic levitation transport system; 210, linear drive coil; 220, magnetic levitation tray; 221, high-temperature permanent magnet; 230, position detection unit; 231, Hall sensor array; 240, gap sensor; 250, levitation dedicated electromagnet; 300, sputtering target material; 400, dynamic air curtain isolation system; 420, isolation vacuum pump; 500, control system. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical scheme and advantages of the present application more clear and obvious, the present application is further described in detail below in combination with specific embodiments.

[0058] Embodiment 1

[0059] Please refer to Figures 1-4 The present application provides a multi-station filter surface coating method, comprising:

[0060] S1, setting a magnetic levitation transport system 200, a sputtering system and a dynamic air curtain isolation system 400 in a single tunnel main vacuum chamber 100, wherein the magnetic levitation transport system 200 includes a linear drive coil 210 installed outside the chamber, a magnetic levitation tray 220 for carrying a substrate installed inside the chamber, and a position detection unit 230 installed outside the chamber, the tray and the coil are magnetically coupled through the chamber wall;

[0061] The sputtering system includes a plurality of sputtering target materials 300 installed in the inner top wall 110 of the chamber in sequence;

[0062] The dynamic air curtain isolation system 400 includes a physical baffle fixedly installed on the inner top wall 110 and located between every two adjacent sputtering target materials 300, and the physical baffle is connected with an isolation vacuum pump 420;

[0063] S2, placing the substrate on the magnetic levitation tray 220, and evacuating the single tunnel main vacuum chamber 100 to a background vacuum better than 1x10⁻ 4 Pa;

[0064] S3, exciting the linear drive coil 210 through the control system 500 to make the magnetic levitation tray 220 realize non-contact active suspension, and being pushed to the lower side of the sputtering target material 300 in start-stop mode;

[0065] S4, when the tray reaches the lower side of any sputtering target material 300, the control system 500 performs closed-loop positioning,

[0066] The closed-loop positioning comprises: detecting an actual position of the tray by the position detection unit 230; comparing the actual position with a preset target position to calculate a position deviation; dynamically adjusting a current of the linear drive coil 210 according to the position deviation to generate a correction magnetic force, so that the tray is magnetically locked and accurately hovered;

[0067] S5, during the hovering of the tray, the corresponding sputtering target material 300 is started to be coated, and the isolation vacuum pump 400 in the dynamic gas curtain isolation system 400 is started, the isolation vacuum pump 420 generates a strong lateral pressure gradient in the isolation interval formed by the physical baffle and the tray, and actively extracts the diffused contaminated atoms to prevent cross contamination;

[0068] Because the isolation vacuum pump 420 generates a strong lateral pressure gradient in the isolation interval formed by the physical baffle and the tray, the pressure gradient can force any contaminated atoms that try to diffuse from one side to the other to be actively extracted and pumped away at high speed, thereby effectively preventing cross contamination;

[0069] S6, after the coating of the current work position is completed, the control system 500 moves the tray to the next sputtering target material 300 without friction, and repeats steps S4 and S5 until the deposition of the multilayer film system is completed;

[0070] The present application provides a kind of multi-station filter surface coating method;In prior art, box type coating machine is used for batch production, there is every time switch cavity door introduction pollution, substrate loading and unloading time is long, cannot continuous production, overall efficiency is low etc.;If using multi-chamber connection system, although it can isolate pollution, but system is extremely complex, equipment investment cost and vacuum maintenance cost is extremely high;

[0071] More importantly, the mechanical transmission components in the vacuum chamber in the prior art, such as bearings, gears and mechanical arms, will generate small particles due to friction when running, which is the particle contamination problem;These particles attached to the surface of the substrate will cause coating defects;At the same time, when multi-material sputtering is carried out in a single chamber, the sputtering atoms of different stations will diffuse with each other, resulting in impure film composition, which is the cross contamination problem;

[0072] The method of the present application aims to solve the above technical problems;The method completes all processes in a single, elongated single tunnel type main vacuum chamber 100, step S1, which greatly reduces the complexity and cost of the vacuum system;

[0073] The first core of the method is to solve the problem of particle pollution by using the magnetic levitation transport system 200; the linear drive coil 210 and the position detection unit 230 of step S1 are installed outside the chamber, on the atmospheric side, and the magnetic levitation tray 220 carrying the substrate is arranged inside the vacuum side; the driving force and the position detection are both through the chamber wall, and the non-magnetic material is realized by magnetic field coupling; in steps S3, S4, and S6, the suspension, propulsion, positioning, and movement of the tray are all in a non-contact state; this design completely eliminates any form of mechanical contact, friction, or transmission components in the vacuum chamber, avoiding the generation of particle pollution;

[0074] The second core of the method is to solve the problem of cross contamination by using the dynamic gas curtain isolation system 400; in step S1, fixed physical baffles and isolation vacuum pumps 420 are arranged between adjacent target materials; during the film coating of the tray suspension in step S5, the isolation vacuum pump 420 creates a horizontal pressure gradient in the isolation space between the physical baffles and the tray, which does not contact each other, forming a local low-pressure area; this is an active cleaning process, and the pressure gradient will force any contamination atoms that attempt to diffuse to be pumped away horizontally at high speed first, thereby effectively preventing cross contamination using the principle of fluid dynamics;

[0075] The method solves the problems of particle pollution and dynamic isolation through magnetic levitation transport, and solves the problem of cross contamination in a synergistic manner, achieving high-purity, high-purity, and high-throughput quasi-continuous film coating production in a single, low-cost chamber structure.

[0076] In step S3, the non-contact active suspension includes: monitoring the gap between the tray and the bottom of the chamber in real time through the gap sensor 240, and adjusting the current of the suspension electromagnet according to the gap to keep the tray at a suspension height of 1-3 mm by the control system 500;

[0077] As a specific embodiment, the non-contact active suspension of step S3 in the above method is further limited; the stable suspension of the tray is realized by active magnetic force feedback;

[0078] In this embodiment, the specific process of the active suspension includes:

[0079] The gap sensor 240 is provided; the gap sensor 240, for example, is a capacitive sensor or an eddy current sensor, is installed inside the cavity, and is used to monitor the vertical gap between the bottom of the magnetic levitation tray 220 and the bottom of the chamber or a special track in real time;

[0080] The control system 500 or the dedicated suspension controller continuously obtains the real-time gap data measured by the gap sensor 240;

[0081] The control system 500 compares the real-time gap data with the preset target suspension height, for example, 1.5 mm, and calculates the gap deviation;

[0082] When there is a deviation, the control system 500 adjusts the current of the suspension dedicated electromagnet 250 at high speed, which can be multiplexed or separated from the propulsion coil, to generate precise attractive or repulsive force to actively resist the influence of gravity or process vibration;

[0083] Through the above feedback control, the tray is always kept within a stable suspension height range, which is preferably 1-3 mm in this embodiment; This active suspension mode ensures that the tray is always in a non-contact state with the cavity during the entire transportation process, including propulsion and hovering.

[0084] In step S4, the magnetic locking makes the tray hover at the center point of the sputtering target material 300 with a positioning accuracy of less than 0.5 mm;

[0085] As a specific embodiment, the technical effects achieved by the closed-loop positioning and magnetic locking in step S4 are limited; this step is the key to realizing high-precision coating in start-stop mode;

[0086] When the tray is propelled to approach the target position, i.e., the center point of the sputtering target material 300, the control system 500 switches from the propulsion mode to the positioning mode; as described above, the position detection unit 230 detects the actual position of the tray, and the control system 500 compares it with the preset target position to instantaneously calculate the position deviation;

[0087] The core of this embodiment is the realization of magnetic locking:

[0088] The controller dynamically and finely adjusts the current of the linear drive coil 210 around the target position according to the calculated position deviation, generating a fine correction magnetic force in the opposite direction of the deviation and proportional to the deviation value;

[0089] If the tray position deviates from the target point, the correction magnetic force will exhibit a magnetic force that pulls back;

[0090] This correction force forms a high-rigidity magnetic locking state - the more the tray position deviates from the target point, the stronger the pull-back magnetic force applied by the controller;

[0091] This mechanism ensures that the tray can be firmly suspended directly below the center point of the sputtering target material 300, resisting any process gas impact or slight drift; in this embodiment, through the above-mentioned closed-loop positioning and magnetic locking, the suspension positioning accuracy of the tray is controlled to be less than 0.5 mm; this high accuracy ensures that the relative position of the substrate and the target material is highly consistent at each start-stop, which is a prerequisite for ensuring film uniformity.

[0092] The isolation vacuum pump 420 is a turbo molecular pump;

[0093] As a specific embodiment, the type of the isolation vacuum pump 420 of the dynamic gas curtain isolation system 400 is defined;

[0094] In this embodiment, the isolation vacuum pump 420 is preferably a turbomolecular pump;

[0095] The technical considerations of using a turbomolecular pump are as follows:

[0096] High pumping speed: turbomolecular pumps have high pumping speed characteristics, which can quickly and efficiently pump away gas molecules in the narrow space formed by the physical baffle and the tray;

[0097] Pressure gradient construction: in order to realize dynamic gas curtain isolation, or fluid dynamics antagonism, a strong lateral pressure gradient, i.e. a local low pressure area, needs to be created between the sputtering station and the isolation chamber, which is at a sputtering pressure of 0.5 Pa; turbomolecular pumps can establish and maintain such a low pressure trap;

[0098] In step S5, when the tray is hovering for coating, the turbomolecular pump is started; any sputtering atoms or process gas molecules that try to diffuse from one side of the station to the adjacent station will be captured by the lateral pressure gradient created by the turbomolecular pump when entering the isolation chamber, and will be preferentially and quickly pumped laterally, so as to prevent the adjacent station from being reached, thereby achieving efficient active isolation.

[0099] The position detection unit 230 is a Hall sensor array 231;

[0100] As a specific embodiment, the specific type of the position detection unit 230 of the magnetic levitation transport system 200 is defined;

[0101] In this embodiment, the position detection unit 230 is a Hall sensor array 231;

[0102] The technical considerations of using a Hall sensor array 231 are as follows:

[0103] Non-contact detection: the magnetic levitation tray 220 usually has a high-temperature permanent magnet 221 inside the rotor; the Hall sensor determines the position of the tray by detecting the magnetic field change generated by the permanent magnet;

[0104] External installation: as described above, the position detection unit 230 is installed outside the chamber, on the atmospheric side; the Hall sensor array 231 can accurately sense the magnetic field of the internal tray permanent magnet through the non-magnetic chamber wall, so as to calculate the actual position of the tray;

[0105] This design avoids deploying complex sensors and signal lines inside the vacuum chamber, simplifies the design of the vacuum system, and improves the reliability of the system; in the closed-loop positioning of step S4, the Hall sensor array 231 provides the control system 500 with a high-precision actual position signal required for calculating the position deviation.

[0106] The plurality of sputtering targets 300 includes a first target for depositing silicon dioxide and a second target for depositing tantalum pentoxide, and the method is implemented by alternately repeating steps S4 and S5 between the first target and the second target to deposit a multilayer optical film system;

[0107] The embodiment provides a specific process flow for preparing a multilayer optical filter, which generally requires the alternate deposition of tens or even hundreds of layers of materials with different refractive indices;

[0108] In the embodiment, among the plurality of sputtering targets 300 provided by the sputtering system, there are a first target for depositing a low-refractive-index material, such as silicon dioxide SiO2, and a second target for depositing a high-refractive-index material, such as tantalum pentoxide Ta2O5;

[0109] The method for preparing a multilayer optical film system is achieved by alternately repeating steps S4, closed-loop positioning, and S5, hover coating, between the first target and the second target;

[0110] The specific flow is as follows:

[0111] Deposition of the first layer: the control system 500 moves the tray under the first target SiO2, performs step S4 to magnetically lock and hover, and performs step S5 to start the first target and the corresponding isolation pump to deposit a layer of SiO2 film;

[0112] Deposition of the second layer: the first target is turned off; the control system 500 moves the tray frictionlessly under the second target Ta2O5, performs step S4 to magnetically lock and hover, and performs step S5 to start the second target and the corresponding isolation pump to deposit a layer of Ta2O5 film on the SiO2 film;

[0113] Circulation: the control system 500 moves the tray again under the first target SiO2, and repeats steps S4 and S5 to deposit a third layer of SiO2 film;

[0114] Repeat: repeat the above process until the required multilayer optical film system is obtained;

[0115] The dynamic gas curtain isolation system 400 of the present application is started every time deposition is performed, i.e., in step S5, to ensure that the SiO2 layer does not mix with Ta impurities and the Ta2O5 layer does not mix with Si impurities, thereby ensuring the high purity of the optical film system.

[0116] Embodiment 2

[0117] Referring to Figures 1-3 A multi-station filter surface coating device comprises:

[0118] A single tunnel type main vacuum chamber 100;

[0119] A magnetic levitation transport system 200,

[0120] The magnetic levitation transport system 200 comprises a linear drive coil 210 mounted outside the chamber, a magnetic levitation tray 220 arranged inside the chamber for carrying a substrate, and a position detection unit 230 mounted outside the chamber;

[0121] The tray and the coil are magnetically coupled through the chamber wall;

[0122] A sputtering system comprising a plurality of sputtering targets 300 mounted in sequence on the inner top wall 110 of the chamber;

[0123] A dynamic air curtain isolation system 400, the dynamic air curtain isolation system 400 comprises a physical baffle fixedly mounted on the inner top wall 110 between each two adjacent sputtering targets 300, and the physical baffle is connected with an isolation vacuum pump 420;

[0124] A control system 500, the control system 500 is connected with the position detection unit 230 and the linear drive coil 210,

[0125] The control system 500 is configured to:

[0126] The linear drive coil 210 is excited to enable the magnetic levitation tray 220 to realize non-contact active suspension and start-stop mode propulsion;

[0127] When the tray reaches below any sputtering target 300, closed-loop positioning is performed, which comprises calculating a position deviation according to a detection signal of the position detection unit 230 and a preset target position, and generating a correction magnetic force to enable the tray to realize magnetic force locking and accurate hovering;

[0128] During the hovering of the tray, the corresponding sputtering target 300 is started, and the isolation vacuum pump 420 is started;

[0129] The present application also provides a multi-station filter surface coating device for implementing the above method;

[0130] The main body of the device is a single, elongated single tunnel type main vacuum chamber 100; all coating processes are completed in this single chamber;

[0131] The magnetic levitation transport system 200 of the device is the core for solving particle pollution; this system realizes partitioning inside and outside the vacuum in structure:

[0132] A linear drive coil 210 is installed as a stator along the tunnel path on the outside of the chamber, i.e. the atmospheric side;

[0133] A magnetic levitation tray 220 is provided as a rotor inside the chamber, i.e. the vacuum side, for carrying the substrate, and the tray is encapsulated with permanent magnets;

[0134] Both are coupled by the non-magnetic chamber wall without mechanical penetration;

[0135] Since the linear drive coil 210 of the magnetic levitation transport system 200 is installed outside the chamber, and the magnetic levitation tray 220 carrying the substrate is accommodated inside the chamber, there is no mechanical connection between the two, and the magnetic field coupling is only realized by the non-magnetic chamber wall, eliminating all mechanical friction components inside the vacuum chamber, eliminating the source of particle generation, and finally solving the particle pollution problem, ensuring a high-purity coating environment;

[0136] The position detection unit 230 is also installed outside the chamber;

[0137] The sputtering system of the device includes a plurality of sputtering targets 300, i.e. workstations, which are sequentially installed on the inner top wall 110, i.e. the ceiling, of the tunnel-type chamber, and perform sputtering facing downward;

[0138] The dynamic air curtain isolation system 400 of the device is the core of solving cross-contamination; the system includes a physical baffle, such as a U-shaped baffle, fixedly installed on the inner top wall 110 and located between every two adjacent sputtering targets 300; the baffle does not contact the magnetic levitation tray 220 passing below; each physical baffle, or the isolation interval formed thereby, is connected with an isolation vacuum pump 420;

[0139] The control system 500 of the device is used to realize the cooperative work of each system; the control system 500 is electrically connected with the external linear drive coil 210 and the position detection unit 230, and controls the sputtering system and the dynamic air curtain isolation system 400;

[0140] The configuration and working logic of the control system 500 are as follows:

[0141] The control system 500 is configured to excite the linear drive coil 210 to generate a traveling magnetic field wave, so that the tray inside is non-contactingly actively suspended and propelled in the tunnel direction in a start-stop mode;

[0142] When the tray is propelled below any sputtering target 300, the control system 500 is configured to perform closed-loop positioning using the signal of the position detection unit 230; the positioning logic includes: calculating the position deviation according to the detection signal and the preset target position, and dynamically adjusting the coil current to generate a correction magnetic force, so that the tray realizes high-precision magnetic force locking and hovering;

[0143] During the tray hovering, the control system 500 is configured to issue instructions to start the film deposition on the sputtering target 300 corresponding to the position, and at the same time, start the isolation vacuum pump 420 located on both sides of the work station to actively prevent cross contamination.

[0144] The magnetic levitation transportation system 200 further comprises a gap sensor 240, and the control system 500 is further configured to adjust the current of the levitation electromagnet according to the signal of the gap sensor 240, so as to keep the tray at a levitation height of 1-3 mm;

[0145] As a specific embodiment, the active levitation function of the magnetic levitation transportation system 200 is specifically limited;

[0146] In the embodiment, the magnetic levitation transportation system 200 further comprises a gap sensor 240, which is, for example, a capacitive sensor or an eddy current sensor, and can be integrated on the cavity or the track, and is used to monitor the vertical gap between the tray and the bottom of the cavity in real time;

[0147] Correspondingly, the control system 500, or the subordinate levitation control module thereof, is further configured to execute the following active levitation logic:

[0148] The control system 500 continuously receives the real-time gap signal sent by the gap sensor 240, compares the signal with the preset levitation height, for example, 1.5 mm, and adjusts the current of the levitation-dedicated electromagnet 250 at high speed and dynamically according to the deviation generated by the comparison, which can be separated from the propulsion coil or reuse the current of a specific phase in the propulsion coil;

[0149] Such active feedback control enables the tray to be stably kept at a levitation height of, for example, 1-3 mm, and actively resist the gravity or process vibration, thereby ensuring the non-contact state during the whole propulsion and hovering process.

[0150] The control system 500 is configured to make the tray hover with a positioning accuracy of less than 0.5 mm;

[0151] As a specific embodiment, the technical effects achieved by the control system 500 executing the closed-loop positioning are limited;

[0152] In the embodiment, the control system 500 is configured to make the tray hover below the center point of the target material with a positioning accuracy of less than 0.5 mm through the magnetic force locking logic;

[0153] As mentioned above, the control system 500 obtains the actual position through the position detection unit 230, compares the actual position with the target position to calculate the position deviation, and then is configured to finely control the current of the driving coil according to the deviation to generate a correction magnetic force proportional to the deviation;

[0154] The configuration ensures that the positioning system has high rigidity, so that the tray can be kept hovering with an accuracy of less than 0.5 mm once it is locked at the target position, which is a key technical index for ensuring the uniformity of film layer thickness and composition;

[0155] The isolation vacuum pump 420 is a turbo molecular pump, and the position detection unit 230 is a Hall sensor array 231;

[0156] The embodiment provides specific selection of two key components in the above device, which is a preferred combination;

[0157] First, the isolation vacuum pump 420 in the dynamic gas curtain isolation system 400 is specifically a turbo molecular pump; as mentioned above, the turbo molecular pump is selected to utilize its high pumping speed characteristics to create an effective lateral pressure gradient in the isolation chamber, a local low-pressure area, to achieve active extraction and isolation of diffusing atoms and prevent cross-contamination;

[0158] Second, the position detection unit 230 in the magnetic levitation transport system 200 is specifically a Hall sensor array 231; as mentioned above, the Hall sensor array 231 is selected to utilize the permanent magnet provided by the magnetic levitation tray 220 to achieve non-contact position detection, and the sensor array can be installed outside the chamber, simplifying the system structure and improving the reliability.

[0159] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and not to limit it. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for coating the surface of a multi-station optical filter, characterized in that, Comprising: S1, setting a magnetic levitation transport system (200), a sputtering system and a dynamic air curtain isolation system (400) in a single tunnel type main vacuum chamber (100), wherein the magnetic levitation transport system (200) comprises a linear drive coil (210) mounted outside the chamber, a magnetic levitation tray (220) for carrying a substrate arranged inside the chamber, and a position detection unit (230) mounted outside the chamber, the tray and the coil are magnetically coupled through the chamber wall; The sputtering system comprises a plurality of sputtering targets (300) mounted in sequence on the inner top wall (110) of the chamber; The dynamic air curtain isolation system (400) comprises a physical baffle fixedly installed on the inner top wall (110) and located between every two adjacent sputtering targets (300), and the physical baffle is connected with an isolation vacuum pump (420); S2, place the substrate on the magnetic levitation tray (220) and evacuate the single tunnel main vacuum chamber (100) to a background vacuum better than 1 x 10⁻⁶ Torr. 4 Pa; S3, exciting the linear drive coil (210) through the control system (500), so that the magnetic levitation tray (220) realizes non-contact active suspension, and is pushed to the lower side of the sputtering target (300) in the "start-stop" mode; S4, when the tray reaches the lower side of any sputtering target (300), the control system (500) performs closed-loop positioning, Wherein, the closed-loop positioning comprises: detecting the actual position of the tray through the position detection unit (230); comparing the actual position with the preset target position to calculate the position deviation; dynamically adjusting the current of the linear drive coil (210) according to the position deviation to generate a correcting magnetic force, so that the tray realizes magnetic force locking and accurate hovering; S5, during the hovering of the tray, the corresponding sputtering target (300) is started to be coated, and the isolation vacuum pump (420) in the dynamic air curtain isolation system (400) is started, the isolation vacuum pump (420) generates a transverse pressure gradient in the isolation space formed by the physical baffle and the tray, and actively extracts the diffused contaminant atoms to prevent cross contamination; S6, after the current station coating is completed, the control system (500) moves the tray to the lower side of the next sputtering target (300) without friction, and repeats steps S4 and S5 until the deposition of the multilayer film system is completed.

2. The multi-station filter coating method of claim 1, wherein, In step S3, the non-contact active suspension comprises: real-time monitoring the gap between the tray and the bottom of the chamber through the gap sensor (240), and the control system (500) adjusts the current of the suspension electromagnet according to the gap, so that the tray is kept at a hovering height of 1-3mm.

3. The multi-station filter coating method of claim 1, wherein, In step S4, the magnetic force locking makes the tray hover at the center point of the sputtering target (300) with a positioning accuracy of less than 0.5mm.

4. The multi-station filter coating method of claim 1, wherein, The isolation vacuum pump (420) is a turbo molecular pump.

5. The multi-station filter coating method of claim 1, wherein, The position detection unit (230) is a Hall sensor array (231).

6. The multi-station filter coating method of claim 1, wherein, The plurality of sputtering targets (300) comprises a first target for depositing silicon dioxide and a second target for depositing tantalum pentoxide, and the method is performed by alternately repeating steps S4 and S5 between the first target and the second target to deposit a multilayer optical film system.

7. A multi-station filter surface coating device based on the multi-station filter surface coating method of any one of claims 1-6, characterized in that, Comprising: A single tunnel type main vacuum chamber (100); A magnetic levitation transport system (200), The magnetic levitation transport system (200) comprises a linear drive coil (210) installed outside the chamber, a magnetic levitation tray (220) arranged inside the chamber for carrying a substrate, and a position detection unit (230) installed outside the chamber. The tray and the coil are coupled by the magnetic field through the chamber wall. A sputtering system, the sputtering system comprising a plurality of sputtering targets (300) installed in sequence on the inner top wall (110) of the chamber; A dynamic gas curtain isolation system (400), the dynamic gas curtain isolation system (400) comprising a physical baffle fixedly installed on the inner top wall (110) between each two adjacent sputtering targets (300), the physical baffle being connected with an isolation vacuum pump (420); A control system (500), the control system (500) being connected with the position detection unit (230) and the linear drive coil (210), The control system (500) is configured to: Excite the linear drive coil (210) to enable the magnetic levitation tray (220) to realize non-contact active suspension and start-stop mode propulsion; When the tray reaches below any sputtering target (300), closed-loop positioning is performed, which comprises calculating a position deviation according to a detection signal of the position detection unit (230) and a preset target position, and generating a correction magnetic force to enable the tray to realize magnetic force locking and accurate hovering; During the hovering of the tray, the corresponding sputtering target (300) is started, and the isolation vacuum pump (420) is started.

8. The multi-station filter coating device of claim 7, wherein: The magnetic levitation transport system (200) further comprises a gap sensor (240), and the control system (500) is further configured to adjust the current of the suspension electromagnet according to the signal of the gap sensor (240) to keep the tray at a suspension height of 1-3mm.

9. The multi-station filter coating device of claim 7, wherein, The control system (500) is configured to enable the tray to hover with a positioning accuracy of less than 0.5mm.

10. The multi-station filter coating device of claim 7, wherein, The isolation vacuum pump (420) is a turbo molecular pump; and the position detection unit (230) is a Hall sensor array (231).

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