Vacuum coating uniformity control method and device based on magnetic field regional dynamic adjustment

Abstract

The invention discloses a vacuum coating uniformity control method and device based on magnetic field regional dynamic adjustment, and relates to the technical field of vacuum coating. The device comprises a partition magnetic field generation module, a film thickness real-time monitoring module, an intelligent control module and a magnetic field-sputtering coupling module. The partition magnetic field generation module is provided with a plurality of groups of independent controllable electromagnetic unit arrays on the back surface of the target material; the film thickness real-time monitoring module is used for acquiring substrate surface film thickness and film coating rate distribution data in real time; the intelligent control module adopts a fuzzy PID algorithm or a machine learning model to generate a dynamic current regulation and control instruction of each electromagnetic unit; and a magnetic field intensity-sputtering rate relational database is arranged in the magnetic field-sputtering coupling module. Through regional independent control, a closed-loop feedback mechanism and a self-adaptive algorithm, fine dynamic adjustment of the target surface magnetic field is realized, the film thickness uniformity is effectively improved, and the target utilization rate and the process suitability are improved.

Description

Technical Field

[0001] This invention relates to the field of vacuum coating technology, and in particular to a method and apparatus for controlling the uniformity of vacuum coating based on regional dynamic adjustment of magnetic field. Background Technology

[0002] In vacuum coating technology, magnetron sputtering is widely used in semiconductors, display panels, and optical thin films due to its fast deposition rate and high film quality. The principle of magnetron sputtering is to use a magnetic field to confine electron movement, enhancing gas ionization efficiency and thus increasing the sputtering rate of the target material. However, in traditional magnetron sputtering equipment, the magnetic field on the target surface is usually generated by a fixed permanent magnet or a monolithic electromagnet. Its magnetic field distribution pattern is singular and cannot be adjusted in real time, leading to the following technical problems: 1. Low target utilization: The fixed magnetic field causes the sputtering area on the target surface to be concentrated, which easily forms an "etching ring", and the unsputtered areas of the target are wasted; 2. Poor film thickness uniformity: The fixed magnetic field distribution leads to uneven film thickness distribution on the substrate surface, with deviations typically exceeding 5%, which cannot meet the requirements for high-precision coating. 3. Weak process adaptability: Different target materials (such as metals, ceramics, alloys) or process parameters (such as air pressure, power) have different requirements for magnetic field distribution, and a fixed magnetic field is difficult to adapt to diverse processes; 4. Low adjustment efficiency: Existing improvement solutions (such as mechanically moving the magnet or adjusting the electromagnet current as a whole) require machine shutdown, which disrupts production continuity and cannot achieve independent regional control and real-time feedback adjustment of the target surface magnetic field, resulting in low intelligence.

[0003] Therefore, there is an urgent need for a vacuum coating uniformity control technology that can achieve regional dynamic adjustment of the target surface magnetic field and combine real-time film thickness feedback to solve the above problems. Summary of the Invention

[0004] To address the shortcomings of existing magnetron sputtering coating equipment, such as the inability to adjust the magnetic field distribution in real time by region, poor film thickness uniformity, low target material utilization, and weak process adaptability, this invention provides a vacuum coating uniformity control method and device based on dynamic adjustment of the magnetic field by region. By independently controlling the magnetic field in different regions, monitoring the film thickness in real time, and adjusting with intelligent feedback, the magnetic field on the target surface is dynamically optimized with fine precision, thereby improving film thickness uniformity and process adaptability.

[0005] To achieve the above objectives, the present invention provides a vacuum coating uniformity control device based on regional dynamic adjustment of magnetic field, comprising: The partitioned magnetic field generation module is located on the back of the target material and contains multiple sets of independently controllable electromagnetic unit arrays, with each electromagnetic unit corresponding to an independent controllable area on the target surface. A real-time film thickness monitoring module is configured around the substrate to acquire real-time data on the film thickness and coating rate distribution on the substrate surface. The intelligent control module is connected to the partitioned magnetic field generation module and the film thickness real-time monitoring module, and is used to generate dynamic current control commands for each electromagnetic unit based on the comparison results of the film thickness and coating rate distribution data with the target value. The magnetic field-sputtering coupling module has a built-in database of magnetic field strength-sputtering rate relationships for different target materials, which is used to optimize the magnetic field distribution strategy in real time in combination with process parameters.

[0006] Furthermore, the partitioned magnetic field generation module divides the target surface into at least 8 independent control regions, and the magnetic field strength of each region can be adjusted in milliseconds.

[0007] Furthermore, the real-time film thickness monitoring module adopts a multi-channel quartz crystal oscillator probe or a mechanical scanning single probe.

[0008] Furthermore, the intelligent control module employs a fuzzy PID algorithm, a machine learning model, or a reinforcement learning model.

[0009] This invention also provides a method for controlling the uniformity of vacuum coating based on regional dynamic adjustment of the magnetic field, comprising the following steps: Step S1: Generate a regionally adjustable magnetic field on the back of the target material through a partitioned magnetic field generation module. The partitioned magnetic field generation module includes multiple sets of independently controllable electromagnetic unit arrays, and each electromagnetic unit corresponds to an independent controllable region on the target surface. Step S2: Obtain real-time data on the film thickness and coating rate distribution on the substrate surface through the real-time film thickness monitoring module; Step S3: The intelligent control module compares the film thickness and coating rate distribution data with the target value, and in conjunction with the magnetic field-sputtering coupling module, generates dynamic current control commands for each electromagnetic unit to dynamically adjust the magnetic field strength in each region.

[0010] Furthermore, in step S3, the intelligent control module uses a fuzzy PID algorithm, a machine learning model, or a reinforcement learning model to generate dynamic current regulation commands.

[0011] Furthermore, in step S1, the target surface is divided into at least 8 independent control regions, and the magnetic field strength of each region can be adjusted in milliseconds.

[0012] Furthermore, in step S2, the real-time film thickness monitoring module collects film thickness data for the entire area every 2 seconds.

[0013] Furthermore, in step S3, the intelligent control module automatically adjusts the current of each electromagnetic unit based on a preset film thickness uniformity threshold, so that the magnetic field strength of the target surface is dynamically optimized within the range of 50-200mT.

[0014] Furthermore, the preset film thickness uniformity threshold is ±3%.

[0015] The coating turntable with bias input implemented in this invention has the following advantages compared with the prior art: This invention achieves independent regional control of the target surface magnetic field by setting up a partitioned magnetic field generation module, which can be precisely adjusted for different regions. The real-time film thickness monitoring module and the intelligent control module form a closed-loop feedback mechanism, which can dynamically correct the magnetic field distribution based on real-time monitoring data, effectively improving the film thickness uniformity and controlling the film thickness uniformity deviation within ±3%. The use of intelligent algorithms and magnetic field-sputtering coupling modules improves the process adaptability and intelligence, can adapt to different target materials and process parameters, and at the same time improves the target material utilization rate and reduces the debugging time. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below.

[0017] Figure 1 This is a schematic diagram of a vacuum coating uniformity control device based on regional dynamic adjustment of magnetic field according to an embodiment of the present invention. Figure 2 This is a flowchart of a vacuum coating uniformity control method based on regional dynamic adjustment of magnetic field according to an embodiment of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., used to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0020] like Figure 1As shown, a preferred embodiment of the present invention provides a vacuum coating uniformity control device based on regional dynamic adjustment of magnetic field, comprising: a regional magnetic field generation module, a real-time film thickness monitoring module, an intelligent control module, and a magnetic field-sputtering coupling module.

[0021] The partitioned magnetic field generation module is located on the back of the target material and contains multiple sets of independently controllable electromagnetic unit arrays, with each electromagnetic unit corresponding to an independent controllable area on the target surface. In this embodiment, the partitioned magnetic field generation module divides the target surface into at least 8 independent control regions, and the magnetic field strength of each region can be adjusted in milliseconds.

[0022] Specifically, the target material is a circular silicon target with a diameter of 300mm, and eight ring-shaped electromagnetic units are arranged on the back side (such as...). Figure 2 As shown, the electromagnetic unit is a coil wound with enameled wire (500 turns, 10Ω resistance). Each coil is driven by an independent digitally controlled DC power supply (output current 0-10A, accuracy ±0.01A), corresponding to 8 independently adjustable fan-shaped regions on the target surface (central angle 45°). The magnetic field strength adjustment range of each region is 50-200mT, and the response time is ≤5ms. Independently adjustable fan-shaped regions on the target surface: 8 independent regions are divided on the target surface according to a central angle of 45°. Each region corresponds to one electromagnetic unit, realizing individual adjustment of the magnetic field strength to control the local sputtering rate.

[0023] A real-time film thickness monitoring module is configured around the substrate to acquire real-time data on the film thickness and coating rate distribution on the substrate surface. In this embodiment, the real-time film thickness monitoring module employs a multi-channel quartz crystal oscillator probe or a mechanically scanning single probe. The quartz crystal oscillator probe is the sensing element for film thickness monitoring. It measures film thickness by measuring changes in crystal oscillation frequency, supporting real-time detection with nanometer-level precision, and is adapted for regional film thickness data acquisition on substrate surfaces. Specifically, for large-size substrates: for substrates such as 600mm × 600mm, the number of electromagnetic units (e.g., 12, with a central angle of 30°) and the corresponding number of quartz crystal oscillator probe channels are increased to expand the target surface control area and improve the accuracy of large-area coverage. For flexible / special substrate applications: it is adapted to substrates such as PET films and Si wafers. By adjusting the substrate stage (e.g., roll-to-roll transport, vacuum chuck), combined with regional magnetic field adjustment, uniform deposition of flexible films or wafer films can be achieved. For high-precision monitoring expansion: supplemented with equipment such as a spectroscopic ellipsometry and X-ray fluorescence thickness gauge, film thickness monitoring with a precision of ±0.01nm is achieved, and feedback accuracy is improved by combining multi-sensor fusion algorithms.

[0024] Specifically, an 8-channel quartz crystal oscillator probe (model INFICON XTC / 3) is used, which is evenly arranged along the circumference of the substrate stage (corresponding one-to-one with the 8 control areas on the target surface). The probe spacing is 50mm, which can monitor the film thickness (measurement range 0-10μm, accuracy ±0.1nm) and coating rate (0-100nm / s) of the corresponding area on the substrate surface in real time.

[0025] The intelligent control module, connected to the partitioned magnetic field generation module and the film thickness real-time monitoring module, is used to generate dynamic current control commands for each electromagnetic unit based on the comparison results of the film thickness and coating rate distribution data with the target value. The electromagnetic unit is the core execution component of the partitioned magnetic field generation module. It is a coil wound with enameled wire (500 turns, 10Ω), driven by a digitally controlled DC power supply, and controls the magnetic field strength of the corresponding area of ​​the target surface through current changes.

[0026] In this embodiment, the intelligent control module employs a fuzzy PID algorithm, a machine learning model, or a reinforcement learning model. The fuzzy PID algorithm is the core algorithm of the intelligent control module. It combines fuzzy logic (handling nonlinearity and time-delay characteristics) with PID control (high-precision adjustment), taking the film thickness deviation and deviation change rate as inputs, and outputting the electromagnetic unit current adjustment amount to achieve dynamic and precise control.

[0027] Specifically, the STM32H743 microcontroller is used as the core, integrating a fuzzy PID algorithm. The inputs of the fuzzy PID algorithm are the film thickness deviation (measured film thickness - target film thickness) and the deviation change rate, and the output is the current adjustment amount of each electromagnetic unit. The controller communicates with the numerical control power supply of the partitioned magnetic field generation module through an RS485 bus, with a command transmission delay of ≤1ms.

[0028] The magnetic field-sputtering coupling module incorporates a database of magnetic field strength-sputtering rate relationships for different target materials, enabling real-time optimization of magnetic field distribution strategies in conjunction with process parameters. Multi-parameter collaborative control: By introducing parameters such as substrate stage rotation speed and sputtering bias, the intelligent control module integrates a MIMO fuzzy PID algorithm, combining the magnetic field-rate model and the bias-ionization rate model to achieve high-precision uniformity control through multi-parameter collaboration. Intelligent upgrade of the coupling model: The static database is upgraded to a machine learning dynamic model (such as a neural network), training the magnetic field-rate prediction model based on historical data, reducing pre-experiment calibration and adapting to complex process conditions. Fast-response process adaptation: Optimized electromagnetic unit coil (high conductivity material) and power supply response speed (≤2ms) to adapt to high deposition rate processes (>100nm / s), ensuring uniform control under high-speed deposition.

[0029] Specifically, a database of magnetic field strength and sputtering rate relationships for silicon targets is built-in. This database was obtained through preliminary experiments: under sputtering power of 1000W and working pressure of 0.5Pa, the sputtering rate is 0.5nm / s at a magnetic field strength of 50mT, 1.2nm / s at 100mT, 1.8nm / s at 150mT, and 2.0nm / s at 200mT. The database supports updating calibration data for different target materials (such as aluminum and copper) via a host computer. Multi-target material adaptation: Utilizing the host computer update function of the magnetic field-sputtering coupling model, the database is extended to target materials such as aluminum, copper, and ITO. Through preliminary experiments, a magnetic field-rate database for different target materials under specific process parameters (such as aluminum target sputtering power of 800W and pressure of 0.6Pa) is obtained, enabling control of multi-material coating uniformity.

[0030] like Figure 2 As shown, a preferred embodiment of the present invention provides a method for controlling the uniformity of vacuum coating based on regional dynamic adjustment of the magnetic field, comprising the following steps: Step S1: A regionally adjustable magnetic field is generated on the back of the target material through a partitioned magnetic field generation module. The partitioned magnetic field generation module includes multiple sets of independently controllable electromagnetic unit arrays, and each electromagnetic unit corresponds to an independent controllable region on the target surface. In one embodiment, the target surface is divided into at least eight independent control regions, and the magnetic field strength of each region can be adjusted in milliseconds.

[0031] Specifically, the target material is a silicon target, and the process parameters are: sputtering power 1000W, working pressure 0.5Pa, target film thickness 500nm, and film thickness uniformity threshold ±3% (i.e., allowable film thickness range 485-515nm). The intelligent control module calls the database of the silicon target in the magnetic field-sputtering coupling model, presets the initial current of 8 electromagnetic units, and makes the initial magnetic field strength of each region of the target surface 100mT (corresponding to a sputtering rate of 1.2nm / s). Film thickness uniformity threshold: the allowable film thickness deviation range, usually expressed as ± percentage (e.g., ±3%), corresponding to the upper and lower limits of the target film thickness (e.g., 485-515nm for 500nm), used to determine whether to trigger magnetic field adjustment.

[0032] Step S2: The film thickness and coating rate distribution data on the substrate surface are acquired in real time through the real-time film thickness monitoring module; In one embodiment, the real-time film thickness monitoring module collects film thickness data for the entire area every 2 seconds.

[0033] Specifically, the film thickness real-time monitoring module is activated, and the 8-channel quartz crystal oscillator probe collects film thickness data of 8 regions on the substrate surface every 2 seconds. At the initial moment (t=0), the film thickness is 0nm and the coating rate is 1.2nm / s.

[0034] In step S3, the intelligent control module compares the film thickness and coating rate distribution data with the target value, and in conjunction with the magnetic field-sputtering coupling module, generates dynamic current control commands for each electromagnetic unit to dynamically adjust the magnetic field strength in each region.

[0035] In one embodiment, the intelligent control module uses a fuzzy PID algorithm, a machine learning model, or a reinforcement learning model to generate dynamic current regulation commands.

[0036] In one embodiment, the intelligent control module automatically adjusts the current of each electromagnetic unit based on a preset film thickness uniformity threshold, thereby dynamically optimizing the magnetic field strength of the target surface within the range of 50-200 mT. This film thickness uniformity threshold is ±3%.

[0037] Specifically, at t=100s, the monitoring data showed that: the film thickness in region 1 was 118nm (rate 0.98nm / s), the film thickness in region 5 was 125nm (rate 1.25nm / s), and the film thickness in the remaining regions was 120±2nm (rate 1.2±0.02nm / s); the film thickness in region 1 was lower than the target value (target film thickness of 120nm at 100s), while the film thickness in region 5 was higher than the target value.

[0038] The intelligent control module calculates the deviation: deviation in region 1 is -2nm, deviation in region 5 is +5nm; it calls the fuzzy PID algorithm and outputs current adjustment commands: the current of the electromagnetic unit in region 1 increases by 0.5A (magnetic field strength increases to 110mT, speed increases to 1.3nm / s), and the current of the electromagnetic unit in region 5 decreases by 0.3A (magnetic field strength decreases to 95mT, speed decreases to 1.15nm / s).

[0039] Continuous monitoring and adjustment: Repeat the above process every 2 seconds until t=417s, when the film thickness of the 8 regions on the substrate surface is stable at 500±10nm (uniformity deviation ±2%≤±3%), then stop the adjustment.

[0040] The final substrate surface film thickness uniformity deviation was ±2.3%, the target surface etching was uniform, and there were no obvious "etching rings," resulting in an 18% improvement in target utilization. Etching rings: Ring-shaped etching marks formed on the target surface due to uneven magnetic field distribution causing differences in sputtering rates. A uniform magnetic field can reduce this phenomenon and improve target utilization. Target utilization optimization: A target consumption factor was added to the coupled model to dynamically adjust the magnetic field in the edge region, slowing down the edge sputtering rate and further improving target utilization (e.g., from 18% to 25%).

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0042] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0043] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A vacuum coating uniformity control device based on regional dynamic adjustment of magnetic field, characterized in that, include: The partitioned magnetic field generation module is located on the back of the target material and contains multiple sets of independently controllable electromagnetic unit arrays, with each electromagnetic unit corresponding to an independent controllable area on the target surface. A real-time film thickness monitoring module is configured around the substrate to acquire real-time data on the film thickness and coating rate distribution on the substrate surface. The intelligent control module is connected to the partitioned magnetic field generation module and the film thickness real-time monitoring module, and is used to generate dynamic current control commands for each electromagnetic unit based on the comparison results of the film thickness and coating rate distribution data with the target value. The magnetic field-sputtering coupling module has a built-in database of magnetic field strength-sputtering rate relationships for different target materials, which is used to optimize the magnetic field distribution strategy in real time in combination with process parameters.

2. The apparatus according to claim 1, characterized in that, The partitioned magnetic field generation module divides the target surface into at least 8 independent control regions, and the magnetic field strength of each region can be adjusted in milliseconds.

3. The apparatus according to claim 1, characterized in that, The real-time film thickness monitoring module uses a multi-channel quartz crystal oscillator probe or a mechanical scanning single probe.

4. The apparatus according to claim 1, characterized in that, The intelligent control module employs a fuzzy PID algorithm, a machine learning model, or a reinforcement learning model.

5. A method for controlling the uniformity of vacuum coating based on regional dynamic adjustment of magnetic field, characterized in that, Includes the following steps: Step S1: Generate a regionally adjustable magnetic field on the back of the target material through a partitioned magnetic field generation module. The partitioned magnetic field generation module includes multiple sets of independently controllable electromagnetic unit arrays, and each electromagnetic unit corresponds to an independent controllable region on the target surface. Step S2: Obtain real-time data on the film thickness and coating rate distribution on the substrate surface through the real-time film thickness monitoring module; Step S3: The intelligent control module compares the film thickness and coating rate distribution data with the target value, and in conjunction with the magnetic field-sputtering coupling module, generates dynamic current control commands for each electromagnetic unit to dynamically adjust the magnetic field strength in each region.

6. The method according to claim 5, characterized in that, In step S3, the intelligent control module uses a fuzzy PID algorithm, a machine learning model, or a reinforcement learning model to generate dynamic current regulation commands.

7. The method according to claim 5, characterized in that, In step S1, the target surface is divided into at least 8 independent control regions, and the magnetic field strength of each region can be adjusted in milliseconds.

8. The method according to claim 5, characterized in that, In step S2, the real-time film thickness monitoring module collects film thickness data for the entire area every 2 seconds.

9. The method according to claim 5, characterized in that, In step S3, the intelligent control module automatically adjusts the current of each electromagnetic unit based on a preset film thickness uniformity threshold, so that the magnetic field strength of the target surface is dynamically optimized within the range of 50-200mT.

10. The method according to claim 9, characterized in that, The preset film thickness uniformity threshold is ±3%.

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