Temperature control method and system for a CVD chemical vapor deposition apparatus

Abstract

The application provides a temperature control method and system for a CVD chemical vapor deposition device, relates to the technical field of temperature control, and determines and optimizes initial cooling constraint conditions by collecting and analyzing the thermal dynamic characteristics of a substrate and a film after film deposition. Secondly, an adaptive cooling transition curve is generated to guide the CVD device to realize precise temperature control and to monitor abnormal states in real time. Finally, the control strategy is dynamically optimized based on the monitoring data to ensure that the temperature is smoothly transitioned to the target value. The method not only improves the stability and response sensitivity of temperature control, reduces the risk of interface thermal stress mutation, but also enhances the adhesion, consistency and density between film layers, improves product yield and process compatibility, and significantly improves the overall reliability of the multilayer film structure.

Description

Technical Field

[0001] This invention relates to the field of temperature control technology, and in particular to a temperature control method and system for CVD chemical vapor deposition equipment. Background Technology

[0002] Chemical vapor deposition (CVD) equipment is widely used in the preparation of semiconductor and thin film materials, requiring extremely high temperature control precision. The current process mainly includes the following steps: First, the reaction chamber and substrate are heated before deposition. The heating system gradually increases the temperature according to the set temperature curve, while simultaneously collecting data from thermocouples or infrared sensors in real time. The heating power is dynamically adjusted through a closed-loop control algorithm (such as PID) to ensure uniform and stable temperature rise. After reaching the process temperature, the reactive gas is introduced and the deposition process begins. After deposition, the system executes a cooling procedure. Typically, the gas flow is stopped first, and then the temperature is reduced by adjusting the heating power, or by combining cooling gas and a cooling circulation system to accelerate cooling, until the equipment temperature returns to a safe level for wafer unloading.

[0003] For example, CN115877890B discloses a temperature control method and system for CVD equipment, which includes: standardizing initial temperature data to obtain standardized temperature data; acquiring timestamp data of the standardized temperature data and performing feature filtering on the standardized temperature data according to the timestamp data to obtain characteristic temperature data; performing thermal power analysis on the characteristic temperature data to obtain power data corresponding to the target CVD equipment; acquiring multiple process flow information and controlling the heater temperature of multiple process flow information according to the power data to generate heater temperature control data corresponding to each process flow information; inputting the heater temperature control data into a preset equipment temperature control analysis model to perform equipment temperature control analysis and obtain the temperature control analysis result corresponding to each process flow information.

[0004] For example, the temperature control system disclosed in Chinese invention patent CN105652919B includes: a temperature measurement circuit for periodically measuring the temperature of a target object and outputting a voltage signal; a control circuit connected to the temperature measurement circuit for receiving the voltage signal, obtaining the current temperature value of the target object based on the voltage signal, and setting a heating duration based on a preset target temperature value and the current temperature value; the heating duration is less than or equal to the measurement cycle of the temperature measurement circuit; and an execution circuit connected to the control circuit for controlling the heating device to heat according to the heating duration to regulate the temperature of the target object. This temperature control system periodically detects the temperature of the target object and sets the conduction time of the heating device within the measurement cycle based on the detected value to regulate the temperature.

[0005] The Chinese invention patent CN115877890B relies excessively on data processing and analysis models. Model construction and optimization not only require a large amount of experimental data, but algorithm debugging is also extremely complex, which increases both system complexity and cost. Furthermore, when the equipment operating environment changes, such as aging of the reaction chamber or fluctuations in gas flow, the model struggles to adapt promptly and accurately, leading to reduced temperature control precision. During the temperature switching phase of multi-process sequence coordinated operation, the model exhibits a delay in responding to real-time dynamic changes, failing to quickly adjust the control strategy and easily causing uncontrollable temperature jumps or overshoots.

[0006] The temperature control method described in Chinese invention patent CN105652919B is relatively simple, relying solely on periodic temperature monitoring and setting heating duration for adjustment. This is insufficient to meet the complex and ever-changing temperature control requirements. In multi-process CVD equipment, the requirements for temperature change rates and stability vary significantly across different process stages, and this system cannot flexibly adjust control parameters to adapt to these changes. Furthermore, its ability to rapidly and accurately adjust temperature is limited during process switching, easily leading to large fluctuations and an inability to effectively suppress thermodynamic fluctuations, thereby causing problems such as thermal stress concentration between film layers.

[0007] Existing technologies suffer from the following technical problems: In CVD equipment operating with multiple process sequences, temperature switching between different deposition processes often occurs during process transitions. Current temperature control systems mainly rely on a preset single closed-loop regulation algorithm (such as PID) for heating / cooling control, resulting in uncontrollable jumps or overshoots in temperature parameters during process switching. Such thermodynamic fluctuations can easily induce thermal stress concentration between film layers, disrupting the stability of stress relaxation and leading to quality hazards such as interfacial microcracks, voids, or decreased adhesion. This becomes a key factor restricting the interface consistency and reliability of multilayer film systems. Summary of the Invention

[0008] To address the technical problem of thermal stress concentration caused by thermodynamic fluctuations in existing technologies, this invention provides a temperature control method and system for CVD (Chemical Vapor Deposition) equipment. The technical solution is as follows:

[0009] On the one hand, a temperature control method for CVD (Chemical Vapor Deposition) equipment is provided. This method includes: Step 1: Using CVD equipment to deposit a thin film on a substrate. After deposition, a substrate-film composite is obtained. The thermodynamic characteristics of the substrate and the film are analyzed to determine the initial cooling constraint conditions for the substrate-film composite. Temperature parameters during the film deposition process are collected and analyzed, and the initial cooling constraint conditions are optimized to obtain the cooling constraint conditions for the substrate-film composite. Step 2: Based on the cooling constraint conditions, a cooling transition curve for the substrate-film composite is generated. The CVD equipment controls the cooling process of the substrate-film composite based on the cooling transition curve, and monitors any abnormal states of the substrate-film composite during the cooling process. Step 3: The coordinates of each center of the substrate-film composite during the cooling process are collected and analyzed to optimize the temperature control of the substrate-film composite until the temperature of the substrate-film composite drops to the target temperature.

[0010] On the other hand, a temperature control system for a CVD (Chemical Vapor Deposition) equipment is provided. This system includes: a constraint optimization module, which uses the CVD equipment to deposit a thin film on a substrate, obtaining a substrate-film composite after deposition. The thermodynamic characteristics of the substrate and film are analyzed to determine the initial cooling constraint conditions for the substrate-film composite. Temperature parameters during the film deposition process are collected and analyzed to optimize the initial cooling constraint conditions, thus obtaining the final cooling constraint conditions for the substrate-film composite. An abnormal state monitoring module generates a cooling transition curve for the substrate-film composite based on the cooling constraint conditions. The CVD equipment uses this cooling transition curve to control the temperature of the substrate-film composite during the cooling process and monitors any abnormal states of the substrate-film composite during cooling. A temperature control optimization module collects and analyzes the center coordinates of the substrate-film composite during the cooling process to optimize the temperature control until the temperature of the substrate-film composite reaches the target temperature.

[0011] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following:

[0012] (1) This invention provides a temperature control method and system for CVD chemical vapor deposition equipment. First, after thin film deposition, the thermodynamic characteristics of the substrate and the thin film are collected and analyzed to determine and optimize the initial cooling constraint conditions. Second, an adaptive cooling transition curve is generated to guide the CVD equipment to achieve precise temperature control and monitor abnormal states in real time. Finally, the control strategy is dynamically optimized based on the monitoring data to ensure a smooth temperature transition to the target value. This method not only improves the stability and response sensitivity of temperature control and reduces the risk of sudden changes in interfacial thermal stress, but also enhances the adhesion, consistency, and density of the thin film layers, improves product yield and process compatibility, and significantly improves the overall reliability of multilayer film structures.

[0013] (2) This invention obtains the thermodynamic characteristic index reflecting the thermal stress adaptability of the substrate-film composite by analysis, and further determines and optimizes the initial cooling constraint conditions of the substrate-film composite, including the critical cooling rate and the rate of change. After deposition, the film characteristic index and cooling constraint strategy are dynamically adjusted by backtracking and comparing the temperature data of the whole process, so as to realize the generation of adaptive temperature control curve and refined cooling management. This can effectively avoid the temperature overshoot and thermal gradient runaway problems that occur when traditional PID control is switched, reduce the probability of sudden change of interface thermal stress, improve the interface integrity and adhesion of the film structure, and enhance the deposition quality and reliability of the multilayer film system.

[0014] (3) This invention divides the cooling process into three stages: uniform temperature rise, holding, and uniform temperature deceleration. A dual-wavelength / single-wavelength laser monitoring mechanism is embedded in each stage. The identification window is dynamically adjusted based on the thermodynamic characteristic index and sampling frequency to accurately capture the center shift trend of the substrate-film composite at different stages. When an effective center shift is detected, a staged warning can be triggered based on the total shift and the rate of increase. The critical cooling rate and rate of change are adjusted in real time to avoid excessively rapid cooling that could cause structural stress mutations. Simultaneously, by introducing a data confidence index, the laser coherence degradation, imaging sensitivity, and material response differences are comprehensively evaluated to ensure the reliability of the monitoring data and the scientific nature of the control strategy. This scheme can achieve high-precision anomaly identification and dynamic intervention under multi-stage temperature control, improving the adaptive capability and stability of the cooling process and ensuring the interface integrity and deposition quality of the multilayer thin film system. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1This is a flowchart of a temperature control method for a CVD chemical vapor deposition equipment provided in an embodiment of the present invention;

[0017] Figure 2 This is a structural diagram of a temperature control system for a CVD chemical vapor deposition equipment provided in an embodiment of the present invention;

[0018] Figure 3 This is a flowchart of generating a cooling transition curve provided in an embodiment of the present invention;

[0019] Figure 4 This is a schematic diagram of the cooling process monitoring provided in an embodiment of the present invention;

[0020] Figure 5 This is a diagram of the temperature control parameter configuration interface provided in an embodiment of the present invention;

[0021] Figure 6 This is a diagram of the device monitoring interface provided in an embodiment of the present invention. Detailed Implementation

[0022] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0023] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0024] In the embodiments of this invention, the terms "image" and "picture" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction between them, they convey the same meaning. Similarly, the terms "of," "corresponding (relevant)," and "corresponding" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction between them, they convey the same meaning.

[0025] In this embodiment of the invention, sometimes a subscript such as W1 may be written in a non-subscript form such as W1. When the difference is not emphasized, the meaning they express is the same.

[0026] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0027] like Figure 1 The flowchart shown is for a temperature control method for a CVD chemical vapor deposition equipment. The process flow of this method may include the following steps:

[0028] Step 1: Thin film deposition is performed on the substrate using a CVD (Chemical Vapor Deposition) system. After deposition, a substrate-film composite is obtained. The thermodynamic characteristics of the substrate and film are analyzed to determine the initial cooling constraint conditions for the substrate-film composite. Temperature parameters during the film deposition process are collected and analyzed to optimize the initial cooling constraint conditions for the substrate-film composite, thereby obtaining the cooling constraint conditions for the substrate-film composite.

[0029] Step 2: Based on the cooling constraint, a cooling transition curve of the substrate-film composite is generated. The CVD chemical vapor deposition equipment controls the temperature of the substrate-film composite during the cooling process based on the cooling transition curve and monitors any abnormal states of the substrate-film composite during the cooling process.

[0030] In CVD (Chemical Vapor Deposition) technology, the raw material gas undergoes a chemical reaction under high temperature conditions, generating solid products on the substrate surface to form a dense and uniform thin film. This film can have electrical conductivity, insulation, wear resistance, optical properties, etc., and is often used in semiconductor devices, optoelectronic devices, protective coatings and other fields. For example, silane (SiH4) is decomposed to deposit a polycrystalline silicon film on the surface of a silicon wafer, or silicon carbide film is deposited on the surface of carbon fiber to enhance its strength and corrosion resistance. The silicon wafer and carbon fiber are the substrates. The substrates, as carriers for the thin film, usually have certain thermal stability, chemical stability and flatness to ensure that the thin film can be formed uniformly during the deposition process.

[0031] The cooling transition curve is a control curve that describes the change of the cooling rate of the substrate-film composite over time. It reflects the dynamic adjustment law of the temperature change rate during the cooling process. The curve includes a stage of uniformly increasing the cooling rate, a stage of maintaining the cooling rate, and a stage of uniformly decreasing the cooling rate.

[0032] Step 3: Collect and analyze the center coordinates of the substrate-film composite during the cooling process to optimize the temperature control of the substrate-film composite until the temperature of the substrate-film composite is reduced to the target temperature.

[0033] Temperature parameters during thin film deposition refer to the measured temperatures at each sampling time point during the thin film deposition process on the substrate.

[0034] Figure 3This is a flowchart illustrating the generation of a cooling transition curve provided in this embodiment of the invention. A thin film is deposited on the substrate using a CVD device to form a substrate-film composite. Subsequently, the thermodynamic characteristics of the substrate and the film are analyzed, and the thermodynamic characteristic index is calculated to determine their respective critical cooling rates and critical cooling rate changes. The minimum of these two values ​​is taken as the initial cooling constraint to ensure overall thermal stability. Based on this, temperature parameters during the deposition process are collected, and the total temperature deviation is analyzed backtrackingly. When the total temperature deviation is within the allowable range, the initial cooling constraint remains unchanged; if the total temperature deviation is not within the allowable range, the thermodynamic characteristic index of the film is reduced, thereby updating the cooling constraint.

[0035] The initial cooling constraint conditions for the substrate-film composite were determined as follows: The thermodynamic characteristics of the substrate and film were analyzed to obtain the thermodynamic characteristic indices of the substrate and film. Based on the thermodynamic characteristic indices of the substrate, the critical cooling rate and the rate of change of the critical cooling rate of the substrate were determined. Based on the thermodynamic characteristic indices of the film, the critical cooling rate and the rate of change of the critical cooling rate of the film were determined. The minimum value between the critical cooling rates of the substrate and the film was selected as the critical cooling rate in the initial cooling constraint conditions. The minimum value between the rate of change of the critical cooling rate of the substrate and the rate of change of the critical cooling rate of the film was selected as the rate of change of the critical cooling rate in the initial cooling constraint conditions. This effectively ensures that the thermal stress distribution between the substrate and the film is within a controllable range, avoiding structural failure problems such as sudden changes in interface stress, film cracking, or delamination caused by the thermal response limit of one material being exceeded. This constraint strategy, which uses the weaker thermal response performance in a dual-material system as the lower limit, helps to maximize the protection of interfacial thermal stability by temperature control parameters during actual cooling processes. This improves the overall reliability and process robustness of the substrate-film composite deposition structure, and is particularly suitable for heterogeneous structural systems constructed through multi-level and multi-material collaboration.

[0036] By matching the thermodynamic characteristic index with the established material cooling behavior response model in the database, the corresponding critical cooling rate value is extracted, which is the maximum safe cooling rate that the substrate can withstand without significant thermal stress accumulation or structural damage. Simultaneously, by referring to the sensitivity of the thermodynamic characteristic index to temperature changes, the response threshold of the substrate to changes in the cooling rate is determined, thus obtaining its critical cooling rate change rate, which is the upper limit of the allowable cooling rate adjustment per unit time.

[0037] The same method is used for the thin film portion.

[0038] Material cooling behavior response models are data models constructed by engineers based on the thermal stress response laws of numerous materials under different cooling conditions. These models reflect the mechanical and structural stability responses of materials to cooling processes under specific thermodynamic characteristics. Typically, these models consist of experimental data and multiphysics simulation results, encompassing the coupling relationship between the coefficient of thermal expansion, elastic limit strain rate, thermal diffusivity, and temperature change rate. They also establish a mapping relationship between cooling rate, thermal stress, and structural stability by incorporating key parameters such as fracture stress, microcrack propagation threshold, and interface delamination critical value. In practical applications, based on the thermodynamic characteristic indices of the substrate or thin film, the model is matched with the response model of the corresponding material in the database to extract its maximum tolerable safe cooling rate (i.e., critical cooling rate). Furthermore, based on the sensitivity of its thermal stress to temperature disturbances, the allowable adjustment range of the cooling rate per unit time (i.e., the critical cooling rate change rate) is derived. This provides quantifiable and dynamically adjustable parameters for the temperature control system, enabling feedforward control of thermal stress risks.

[0039] Specifically, the thermodynamic characteristic indices are analyzed using the following methods: Thermodynamic characteristics include the coefficient of thermal expansion, the elastic limit strain rate, and the thermal diffusivity. The coefficient of thermal expansion represents the material's ability to undergo linear dimensional changes under unit temperature variations, reflecting the strain trend generated by the material in a changing thermal field. The elastic limit strain rate describes the maximum strain rate a material can withstand without permanent deformation, reflecting its mechanical limit in responding rapidly to thermal stress. The thermal diffusivity characterizes the speed of heat conduction within the material; it is a comprehensive indicator of the combined effects of thermal conductivity, heat capacity, and density, reflecting the efficiency of temperature field propagation within the material. The thermodynamic characteristics of the substrate are determined by on-site technicians based on measured results or material properties. The database is verified and uploaded to the system; the thermodynamic characteristics of the thin film are obtained by matching the film thickness and material type from the database. First, the material type of the deposited film (such as SiO2, Al2O3, TiN, etc.) is identified. Then, based on the film thickness recorded in the actual deposition process, the thermodynamic characteristics of the material at different thickness scales are consulted in the database (the thermodynamic behavior of some materials at the nanoscale differs from that at the macroscale). The thickness-performance mapping model (such as the thickness-performance mapping table) is used to derive the parameters. Finally, the thermal expansion coefficient, elastic limit strain rate and thermal diffusivity of the film under the current thickness conditions are determined and entered into the system as input parameters for thermodynamic analysis.

[0040] Based on the influence relationship between the coefficient of thermal expansion, the elastic limit strain rate, and the thermal diffusivity on the thermodynamic characteristic index, corresponding boundary values ​​are assigned to the coefficient of thermal expansion, the elastic limit strain rate, and the thermal diffusivity, respectively.

[0041] The coefficient of thermal expansion, elastic limit strain rate, and thermal diffusivity are assigned different influences on the thermodynamic characteristic index by weighted proportional values. The thermodynamic characteristic index is derived by integrating the corresponding boundary values ​​and weighted proportional values ​​of the coefficient of thermal expansion, elastic limit strain rate, and thermal diffusivity. Specifically, the integration process is as follows: the ratio between the boundary coefficient of thermal expansion and the coefficient of thermal expansion is allocated to the thermodynamic characteristic index using a weighted proportional value of the coefficient of thermal expansion, thus obtaining the influence component of the coefficient of thermal expansion on the thermodynamic characteristic index; the ratio between the elastic limit strain rate and the boundary elastic limit strain rate is allocated to the thermodynamic characteristic index using a weighted proportional value of the elastic limit strain rate, thus obtaining the influence component of the elastic limit strain rate on the thermodynamic characteristic index; and the ratio between the thermal diffusivity and the boundary thermal diffusivity is allocated to the thermodynamic characteristic index using a weighted proportional value of the thermal diffusivity, thus obtaining the influence component of the thermal diffusivity on the thermodynamic characteristic index. All influence components are then summarized to form the thermodynamic characteristic index.

[0042] JTEC is the preset defined coefficient of thermal expansion in the database, TEC is the coefficient of thermal expansion, ELS is the elastic limit strain rate, JELS is the preset defined elastic limit strain rate in the database, BTD is the thermal diffusivity, JBTD is the preset defined thermal diffusivity in the database; the defined coefficient of thermal expansion represents the upper limit of the coefficient of thermal expansion; the defined elastic limit strain rate represents the lower limit of the elastic limit strain rate; the defined thermal diffusivity represents the lower limit of the thermal diffusivity.

[0043] Thermodynamic characteristic index, used to digitally characterize a material's ability to adapt to changes in thermal stress during cooling, is specifically expressed as:

[0044] ;

[0045] In the formula, TDP is the thermodynamic characteristic index, D1 is the preset weighted ratio of the thermal expansion coefficient in the database, D2 is the preset weighted ratio of the elastic limit strain rate in the database, and D3 is the preset weighted ratio of the thermal diffusivity in the database.

[0046] The weighted ratio of the coefficient of thermal expansion indicates the influence of the ratio between the defining coefficient of thermal expansion and the coefficient of elastic expansion on the thermodynamic characteristic index; the weighted ratio of the elastic limit strain rate indicates the influence of the ratio between the elastic limit strain rate and the defined elastic limit strain rate on the thermodynamic characteristic index; the weighted ratio of thermal diffusivity indicates the influence of the ratio between the thermal diffusivity and the defined thermal diffusivity on the thermodynamic characteristic index. The database includes pre-set measured values ​​of the coefficient of thermal expansion, elastic limit strain rate, and thermal diffusivity of multiple typical materials (such as typical metallic materials) under different thermal environmental conditions, along with a table showing their thermal stress adaptation during actual cooling processes. Currently, using data analysis methods such as principal component analysis (PCA) or entropy weighting, the contribution of thermal expansion coefficient, elastic limit strain rate, and thermal diffusivity to the overall thermal stress adaptability is extracted. This determines the sensitivity and decisive weight of each index in reflecting the thermodynamic behavior of the material. Finally, based on the above calculation results, weighted ratio values ​​D1, D2, and D3 are determined to express the degree of influence of thermal expansion coefficient, elastic limit strain rate, and thermal diffusivity on the thermodynamic characteristic index, respectively. This ensures that the constructed thermodynamic characteristic index has strong distinguishability and responsiveness among different materials. The values ​​of D1, D2, and D3 are all between 0 and 1.

[0047] During the evolution of thermal stress, the coefficient of thermal expansion determines the magnitude of dimensional changes in a material under temperature variations. A large coefficient of thermal expansion leads to significant volume shrinkage during cooling, easily causing thermal stress concentration at the interface. In this case, a sufficiently high elastic limit strain rate can enhance the material's response to rapid thermal strain and suppress microcrack propagation caused by stress concentration. In other words, increasing the elastic limit strain rate can offset the thermal stress risk associated with a large coefficient of thermal expansion. Furthermore, a higher thermal diffusivity results in faster heat transfer within the material and a more uniform temperature gradient distribution, effectively mitigating thermal stress concentration caused by uneven thermal expansion. Therefore, increasing the thermal diffusivity indirectly reduces dependence on a high elastic limit strain rate. In summary, an increased coefficient of thermal expansion leads to greater thermal strain; a higher elastic limit strain rate is required to adapt to stress evolution. Simultaneously, a higher thermal diffusivity helps balance temperature distribution and reduce abrupt changes in thermal stress. These three factors jointly influence the value of thermodynamic characteristic indices, thereby quantitatively characterizing the material's thermal adaptability during the cooling phase.

[0048] Furthermore, the initial cooling constraints of the substrate-film composite were optimized. Specifically, after deposition, a backtracking analysis of the deposition process temperature deviation was initiated. The measured temperatures at each sampling time point during the thin film deposition process were analyzed against the preset process temperatures, and the total temperature deviation was calculated. Temperature deviation = Measured temperature The preset process temperature indicates a risk of overheating if the temperature deviation is positive, and a risk of insufficient cooling if the temperature deviation is negative. When summing the temperature deviations of multiple sampling points, the positive and negative signs are retained, which can reflect the overall deviation trend.

[0049] The total temperature deviation is compared with the preset allowable deviation range. If the total temperature deviation falls within the allowable deviation range, the initial cooling constraint is directly used as the cooling constraint for the substrate-film composite. The allowable deviation range refers to the acceptable temperature error range in the process settings, which is set by relevant technical personnel based on factors such as experience data, material thermal sensitivity, and equipment stability.

[0050] If the total temperature deviation is outside the allowable range, the thermodynamic characteristic index of the thin film is reduced based on the total temperature deviation. This updates the critical cooling rate and the rate of change of the critical cooling rate, thereby optimizing the initial cooling constraints. The optimized conditions are then labeled as the cooling constraints for the substrate-thin film composite. When the total temperature deviation is outside the allowable range, it indicates a significant temperature control deviation during film deposition, which may lead to abnormal thermal stress accumulation, interface structure distortion, and a decrease in the overall thermal response capability of the substrate-thin film composite. Therefore, reducing the thermodynamic characteristic index of the thin film characterizes its decreasing thermal stability and stress adaptability during cooling, thus guiding a more conservative adjustment of subsequent cooling strategies.

[0051] The critical cooling rate change rate and critical cooling rate mentioned in this specification refer to their unsigned positive values.

[0052] Monitoring abnormal states of the substrate-film composite during the cooling process specifically refers to monitoring abnormal states of the substrate-film composite during the uniformly increasing cooling rate stage, the maintaining cooling rate stage, and the uniformly decreasing cooling rate stage. The coordinates of each center of the substrate-film composite during the cooling process are collected and analyzed to optimize the temperature control of the substrate-film composite, thereby determining whether to issue an early warning for the cooling process of the substrate-film composite.

[0053] The center coordinates of the substrate-film composite during the cooling process refer to the center coordinates of several physical monitoring points on the surface of the substrate-film composite, which are used to reflect the thermal deformation, micro-displacement or thermal stress migration state of the structure. Some of these physical monitoring points are set by relevant technical personnel.

[0054] The cooling transition curve of the substrate-film composite includes a uniformly increasing cooling rate stage, a maintaining cooling rate stage, and a uniformly decreasing cooling rate stage. The uniformly increasing cooling rate stage refers to increasing the cooling rate of the substrate-film composite based on the critical cooling rate change rate of the substrate-film composite until the cooling rate of the substrate-film composite increases to the critical cooling rate.

[0055] The cooling rate maintenance phase refers to cooling the substrate-film composite based on its critical cooling rate. The specific duration of this phase is determined by the dynamic equilibrium time of heat conduction and heat diffusion at the substrate-film interface under stable thermal stress response. By establishing a heat conduction model and combining parameters such as the thermal conductivity and thermal diffusivity of the film and substrate materials, a finite element simulation method (such as COMSOL Multiphysics) is used to dynamically simulate the temperature field evolution process. By analyzing the rate of change of the temperature gradient per unit thickness of the interface through simulation, the time point at which the thermal gradient tends to stabilize (rate of change equals 0) is the end time point of the cooling rate maintenance phase.

[0056] When the rate of change of the temperature gradient equals zero, it indicates that the temperature distribution within a unit thickness has stabilized, the heat flow within the substrate-film composite no longer changes drastically, and the risk of further accumulation of thermal stress is significantly reduced. At this point, the temperature of the substrate-film composite is close to the target temperature. If a high cooling rate is maintained, the substrate-film composite may suddenly reach the final temperature before the stress release is fully completed, inducing stress imbalance or structural deformation. Therefore, taking the point when the rate of change of the temperature gradient equals zero as the end point of the cooling rate maintenance stage not only helps to ensure that the thermal stress is fully released under stable conditions, but also provides the starting conditions for temperature and stress equilibrium in the subsequent slow cooling stage, thereby improving the overall thermal stability and film quality of the composite.

[0057] Two-dimensional or three-dimensional thermal conduction models of the substrate and thin film can be established in a finite element simulation platform (such as COMSOL Multiphysics). Material parameters such as thermal conductivity, thermal diffusivity, specific heat capacity, and density can be input, interface thermal contact conditions can be set, and cooling boundaries (such as convective heat transfer or ambient temperature) can be applied. Transient thermal analysis can be carried out. During the simulation, the evolution trend of interface temperature gradient, temperature difference change rate, and heat flux density can be tracked. The time point when the thermal gradient tends to stabilize (change rate equals 0) can be determined as a sign of the establishment of dynamic equilibrium, thereby determining the reasonable duration of maintaining the cooling rate and providing a basis for subsequent precise temperature control.

[0058] The uniformly slowed-down cooling rate stage refers to the stage where the cooling rate of the substrate-film composite is reduced uniformly based on the critical cooling rate change rate of the substrate-film composite until the cooling rate of the substrate-film composite is reduced to the target cooling rate, and then the substrate-film composite is cooled at the target cooling rate until the substrate-film composite reaches the preset target temperature.

[0059] The determination of whether to issue an early warning for the cooling process of the substrate-film composite is as follows: During the uniformly increasing and decreasing cooling rate phase, the abnormal state of the substrate-film composite is monitored by a dual-wavelength laser from the monitoring device and a defined sampling frequency. The information of each center of the substrate-film composite is collected at preset intervals in the database. The information of each center includes the spatial coordinate data of each center. The size of the identification window is determined by obtaining the data confidence index of the monitoring device, thereby identifying the coordinates of each center of the substrate-film composite and determining whether there is a center coordinate deviation. The sampling frequency is defined as the maximum sampling frequency preset in the database.

[0060] A higher data confidence index indicates better data quality, allowing the recognition window to be reduced accordingly to improve positioning accuracy. Conversely, a lower data confidence index requires a larger recognition window to ensure effective capture and recognition of the center point, balancing accuracy and stability. The database stores the correspondence between the data confidence index and the recognition window size, including but not limited to mapping tables and mapping functions. Therefore, by using the data confidence index as an index in the database, the corresponding recognition window size can be obtained.

[0061] Based on a defined recognition window, image processing algorithms (such as edge detection, feature matching, and sub-pixel localization techniques) are used to analyze the point cloud data of several physical detection points obtained by laser scanning, thereby extracting the center coordinates of each physical detection point.

[0062] The monitoring device uses laser beams with two different wavelengths to irradiate the substrate-film composite to achieve higher sensitivity and depth resolution surface condition detection. The dual-wavelength setting can be used to distinguish the reflection characteristics between different material layers, thereby enhancing the ability to identify changes in the composite interface. Based on the required time resolution and monitoring accuracy, the time interval for data acquisition (usually in Hz) is preset to ensure timely capture of thermal deformation, displacement, or stress anomalies. The monitoring device is set to acquire data at fixed time intervals, such as once every 100 milliseconds, thereby achieving equidistant monitoring in the time dimension, which helps in subsequent deviation trend analysis and change determination.

[0063] The shortest distance analysis is performed between the currently collected center coordinates and the initial coordinates of each center to obtain the center deviation distance. The deviation distances are then accumulated to obtain the total center offset. If the total center offset is greater than 0, it is determined that there is a center coordinate deviation. If the total center offset is equal to 0, it is determined that there is no center coordinate deviation.

[0064] The monitoring device includes: a dual-wavelength laser interferometer / coherent interferometry system: which performs interferometric measurements on the surface or internal scattering points of the thin film using dual-wavelength lasers, enabling precise detection of submicron-level displacement changes; and a thermal imaging and optical imaging module: which captures the temperature distribution and morphological micro-changes of the substrate-thin film composite in real time during the cooling process, and uses image processing algorithms (such as edge detection algorithms and morphological processing algorithms) to locate each center point.

[0065] If there is no center coordinate deviation, the uniform temperature rise and fall rate stage is continuously monitored; if there is a center coordinate deviation, it is determined whether it is an invalid center coordinate deviation. If it is an invalid center coordinate deviation, the uniform temperature rise and fall rate stage is continuously monitored.

[0066] If it is an effective center deviation, the total center offset of the substrate-film composite is obtained and compared with the defined offset. If the total center offset of the substrate-film composite is less than the defined offset, it is marked as an allowable deviation. At the same time, the rising rate of the total center offset of the substrate-film composite is analyzed. If the rising rate of the total center offset of the substrate-film composite is less than the preset rising rate of the defined center offset in the database, the uniform temperature increase and decrease rate stage is continuously monitored. If the rising rate of the total center offset of the substrate-film composite is greater than or equal to the rising rate of the defined center offset, the decrease in the first rate of change is obtained, thereby reducing and adjusting the rate of change of the critical cooling rate, thereby updating the cooling constraint conditions of the substrate-film composite, and the uniform temperature increase and decrease rate stage is continuously monitored.

[0067] The rate of increase of the total center offset of the substrate-film composite refers to the trend of change in the geometric center position caused by the difference in thermal expansion between the substrate and the film. Essentially, it is reflected in the increment of the total center offset per unit time.

[0068] Define the rate of increase of the total center offset, which refers to the upper limit of the rate of increase of the total center offset.

[0069] Subtracting the reduction in the first rate of change from the rate of change of the critical cooling rate gives the reduced rate of change of the critical cooling rate. The reduction in the rate of change refers to the amount by which the rate of change of the critical cooling rate needs to be reduced. The "first" in the reduction in the first rate of change is used to distinguish the magnitude of the reduction. The same applies to the reduction in the second rate of change.

[0070] By comparing the total center offset of the substrate-film composite with the defined offset, the permissible deviation state can be accurately identified. Then, when the total center offset is within an acceptable range, dynamic evaluation is performed by combining the rate of increase of the total center offset with the preset defined rate of increase of the total center offset. This helps to detect the thermal stress evolution trend in advance and avoid the risk of sudden deformation. If an abnormal rate of increase of the total center offset is detected, the control strategy for the cooling stage is further dynamically optimized by adjusting the rate of change of the critical cooling rate. This enables real-time correction of the cooling constraints, thereby ensuring the thermal stability and interface integrity of the film deposition process and improving the safety and precision of process control.

[0071] If the total center offset of the substrate-film composite is greater than or equal to the defined offset, the reduction in the critical cooling rate is determined based on the total center offset. This reduction can be determined through the correspondence between the total center offset and the reduction in the critical cooling rate, which includes, but is not limited to, mapping tables and mapping functions. The current critical cooling rate is reduced by subtracting the reduction in the critical cooling rate, thereby adjusting the critical cooling rate. Furthermore, the interval for collecting center information of the substrate-film composite is shortened based on the total center offset. This reduction can be determined through the correspondence between the total center offset and the reduction in the interval, which includes, but is not limited to, mapping tables and mapping functions. The shortened interval duration is obtained by subtracting the reduction in interval duration from the duration. After adjustment, if the total center offset of the substrate-film composite is still greater than or equal to the defined offset, the critical cooling rate change rate is set to the minimum cooling rate change rate, and a first-stage warning is issued for the cooling process of the substrate-film composite. If the total center offset of the substrate-film composite is not greater than or equal to the defined offset, the uniform increase and decrease rate stage is continuously monitored. The first-stage warning is a special warning mechanism for the substrate-film composite during the uniform increase and decrease rate stage. The data acquisition frequency is increased to the highest system capacity (e.g., once every 20ms) to achieve near real-time monitoring. The first-stage warning indicator is displayed on the operation interface, accompanied by a buzzer or voice prompt.

[0072] During the uniformly increasing and decreasing cooling rate phase, as the thermal field continuously changes, non-uniform thermal strain occurs between the substrate and the thin film. When the total center offset is continuously increasing, and the rate of increase exceeds the preset threshold in the database, it indicates that thermal stress is accumulating and there is a risk of interface instability. At this point, to prevent further exacerbation of thermal stress, the system adjusts the rate of change of the critical cooling rate to slow down the increase in the cooling rate, thereby reducing the rate of change of the thermal gradient and slowing down the growth of thermal stress, thus achieving proactive intervention in interfacial thermal shock. In addition, the larger the total center offset, the higher the stress state of the structure. Therefore, it is necessary to simultaneously shorten the acquisition interval and increase the data sampling frequency to obtain stress response information with higher temporal resolution, enabling rapid capture and accurate judgment of dynamic trends. If, after adjustment, the total center offset of the substrate-thin film composite is still greater than or equal to the threshold offset, the rate of change of the critical cooling rate is reduced to a minimum, and the first-stage early warning mechanism is activated, acquiring center information at the highest system frequency to achieve near real-time monitoring. The above strategies can be used to implement graded control and early warning response based on the thermal stress evolution trend, effectively improve the thermal stability and interface integrity of the cooling process, and enhance the safety and robustness of thin film deposition process under complex thermal field disturbances.

[0073] In this invention, adjusting and defining the rate of change of cooling rate and defining the cooling rate are both to ensure that the stress of the substrate-film composite can be effectively released and tend to be balanced during the cooling process, thereby suppressing structural defects, crack generation or interface peeling caused by sudden thermal stress, and improving the structural integrity of the film interface and the film quality.

[0074] The monitoring parameters of the substrate-film composite are switched by continuously monitoring the uniformly increasing and decreasing temperature rate during the initial stage until the temperature rate is maintained.

[0075] Invalid center coordinate deviation refers to the disordered direction of each center coordinate deviation or the total center offset showing a step change but then stabilizing.

[0076] The defined offset, which characterizes the upper limit of the total center offset of the substrate-film composite, is determined by the thermodynamic characteristic index of the substrate-film composite. The defined offset takes into account the influence of multiple factors such as the thermal expansion characteristics of the material itself, the interfacial adhesion performance, and the structural stability. It is used to guide the formulation of temperature control strategies and the rationality assessment of the interfacial stress adjustment process, ensuring that the substrate-film composite can maintain functional integrity and structural reliability under thermal cycling conditions.

[0077] The thermodynamic characteristic index of the substrate-film composite is obtained by weighting and summing the thermodynamic characteristic indices of the substrate and the film. The weighting values ​​of the thermodynamic characteristic indices of the substrate and the film are determined by technical personnel.

[0078] The data confidence index of the monitoring device is analyzed as follows: based on the thermodynamic characteristic index of the substrate-film composite, the data confidence increment is matched from the database; the data confidence increment refers to the increase in the data confidence index, which can be obtained by querying the thermodynamic characteristic index-data confidence increment mapping table in the database.

[0079] Thermodynamic characteristic indices comprehensively reflect the stability and response consistency of the substrate-film composite during heating, essentially linking the coupling characteristics of the temperature field, stress field, and intermaterial thermophysical parameters. When the substrate-film composite exhibits a low thermal stress gradient, a stable thermal diffusion path, and predictable strain evolution behavior during temperature-controlled regulation, it indicates that its thermal response process has high repeatability and strong physical mechanism constraints. The thermodynamic characteristic indices formed under these conditions possess good characterization accuracy and time-series stability. A large database of historical experimental and simulation data has established a statistical mapping table between these characteristic indices and their corresponding data confidence increments. Therefore, based on the currently calculated thermodynamic characteristic indices, methods such as pattern recognition and regression analysis can be used to accurately match the corresponding data confidence increments from the database. This is used to quantify the increase in the credibility of the current monitoring data during the thermal evolution process. This matching method not only improves the accuracy of data confidence modeling but also realizes a physical feedback loop between heat and data response.

[0080] The laser coherence degradation rate and imaging temperature sensitivity of the monitoring device are obtained. The laser coherence degradation rate refers to the rate at which the coherence of the output laser beam of the laser monitoring device decreases over time or due to external disturbances (such as thermal drift or mechanical vibration). Coherence represents the phase consistency of the laser wave and is a core indicator for precision measurements such as interferometry, imaging, and ranging. A higher laser coherence degradation rate indicates a faster decrease in coherence, suggesting poorer system stability and greater sensitivity to external interference. Conversely, a lower laser coherence degradation rate indicates a more robust system to disturbances, a longer time the laser maintains coherence, and better maintenance of interference fringe clarity and measurement accuracy. Imaging temperature sensitivity refers to the response of the monitoring device's imaging quality (such as resolution, contrast, or grayscale mean) to temperature changes under different temperature conditions. The laser coherence degradation rate can be measured using the spectral linewidth broadening method, while the imaging temperature sensitivity is uploaded by technical personnel.

[0081] The temperature change rate of the substrate-film composite is obtained, and the boundary temperature change rate of the substrate-film composite is matched according to the imaging temperature sensitivity of the monitoring device. This can be obtained by querying the imaging temperature sensitivity-bound temperature change rate mapping table stored in the database, where the boundary temperature change rate represents the maximum allowable temperature change rate.

[0082] The temperature change rate of a substrate-film composite refers to the rate at which the temperature of the substrate-film composite changes per unit time. A high-precision temperature sensor (such as a thermocouple, infrared temperature sensor, or MEMS thermistor) is deployed at or near the interface between the substrate and the film, and a fixed time interval (such as sampling once per second) is set to record a continuous temperature sequence, thereby calculating the rate at which the temperature of the substrate-film composite changes per unit time.

[0083] By distinguishing the degree of influence of the ratio between the laser coherence degradation rate and the defined laser coherence degradation rate, as well as the deviation between the temperature change rate and the defined temperature change rate, on the data confidence index, different degrees of influence are summarized, and the influence of the data confidence increment on the data confidence index is also incorporated, thus obtaining the data confidence index of the monitoring device.

[0084] The data confidence index of a monitoring device is an indicator used to quantitatively evaluate the reliability and accuracy of the data collected by the monitoring device. The specific analysis process is as follows:

[0085] ;

[0086] In the formula, DCI is the data confidence index of the monitoring device, DR is the laser coherence degradation rate of the monitoring device, JDR is the preset defined laser coherence degradation rate in the database, DF is the preset laser coherence degradation rate metric in the database, TCR is the temperature change rate of the substrate-film composite, CTCR is the defined temperature change rate of the substrate-film composite, DG is the temperature change rate metric, and DI is the data confidence increment.

[0087] The laser coherence degradation rate is defined as the maximum allowable value of the laser coherence degradation rate.

[0088] The laser coherence degradation rate metric indicates the degree to which the ratio between the laser coherence degradation rate and the defined laser coherence degradation rate affects the data confidence index; the temperature change rate metric indicates the degree to which the deviation between the temperature change rate and the defined temperature change rate affects the data confidence index. The database stores tables of laser coherence degradation rate metrics and temperature change rate metrics. By inputting the laser coherence degradation rate and the temperature change rate, the corresponding laser coherence degradation rate metric and temperature change rate metric can be obtained.

[0089] A greater deviation between the actual temperature change rate and the defined temperature change rate indicates a decrease in the stability of the system's thermal environment and an increase in thermal disturbance. In this context, the refractive index distribution of the medium in the optical path fluctuates more drastically, further inducing nonlinear degradation of laser coherence. This leads to an increase in the laser coherence degradation rate, which directly affects the stability and accuracy of interferometric imaging, resulting in a decrease in interference fringe quality, a lower signal-to-noise ratio, and consequently, a weakening of the reliability of the system's acquired data, manifested as a decrease in the data confidence index. In summary, the greater the deviation in the temperature change rate, the more significant the laser coherence degradation, the weaker the system's interference capability, and ultimately, a decrease in the data confidence index. When the data confidence index decreases, the system needs to expand the recognition window to improve the target acquisition tolerance; conversely, if the data confidence index is high, the recognition window can be correspondingly reduced to improve positioning accuracy. The system database pre-defines the mapping relationship between the data confidence index and the recognition window size, allowing for dynamic adjustment of the recognition strategy based on the current confidence index, thereby achieving a balance between accuracy and stability under thermal disturbance intervention.

[0090] Switching the monitoring parameters of the substrate-film composite specifically refers to: during the cooling rate maintenance phase, monitoring the abnormal state of the substrate-film composite using a single-wavelength laser from the monitoring device and a preset normal acquisition frequency; acquiring information about each center of the substrate-film composite at preset intervals; determining the size of the identification window by obtaining the data confidence index from the monitoring device; thereby identifying the coordinates of each center of the substrate-film composite and determining whether there is a center coordinate deviation.

[0091] The primary objective of the cooling rate maintenance phase is to stably and continuously monitor the overall temperature field and deformation trend of the substrate-film composite, focusing on minute displacements and deviations caused by thermal stress. During this phase, the interface structure between the substrate and the film is relatively stable, and the interlayer reflection characteristics change little; therefore, it is unnecessary to use multi-wavelength lasers to distinguish the reflection differences between different material layers. A single-wavelength laser illuminates the composite surface, collects the reflection signal, and performs continuous data acquisition at a preset sampling frequency (e.g., once every 100 milliseconds), achieving high temporal resolution dynamic monitoring. Due to its fixed wavelength, simplified system, and stable signal, the single-wavelength laser can efficiently acquire reflection information from the substrate-film composite surface, meeting the high-sensitivity detection requirements for thermal deformation and geometric displacement. Therefore, during the cooling rate maintenance phase, a single-wavelength laser is sufficient to support thermal stress monitoring and anomaly assessment, ensuring both real-time monitoring and stability while reducing system complexity and cost.

[0092] During the cooling rate maintenance phase, single-wavelength lasers, with their advantages of low cost, high real-time performance, and surface sensitivity, accurately identify the center coordinate deviation of the substrate-film composite through high-frequency acquisition and dynamic confidence index analysis, thus meeting the stable monitoring requirements of this phase.

[0093] Monitoring parameters refer to key indicators used to monitor the state of the substrate-film composite during the cooling process. These mainly include: laser scanning signal, acquisition frequency, sampling time interval, data confidence index, and center coordinate information, which are used to identify whether there is a center deviation or abnormal state of the substrate-film composite.

[0094] If there is no center coordinate deviation, continue monitoring during the cooling rate maintenance phase; if there is a center coordinate deviation, determine whether it is an invalid center coordinate deviation. If it is an invalid center coordinate deviation, continue monitoring during the cooling rate maintenance phase.

[0095] If the deviation is valid, the total center offset of the substrate-film composite is obtained and compared with the defined offset. If the total center offset of the substrate-film composite is less than the defined offset, it is marked as an allowable deviation. At the same time, the rate of increase of the total center offset of the substrate-film composite is analyzed. If the rate of increase of the total center offset of the substrate-film composite is less than the preset rate of increase of the defined center offset in the database, the cooling rate is continuously monitored. If the rate of increase of the total center offset of the substrate-film composite is greater than or equal to the rate of increase of the defined center offset, the first rate reduction magnitude is obtained, thereby reducing and adjusting the critical cooling rate, thus updating the cooling constraint conditions of the substrate-film composite, and continuously monitoring the cooling rate maintenance phase. The critical cooling rate is subtracted from the first rate reduction magnitude, and the result is recorded as the critical cooling rate after reduction adjustment. This helps to detect the thermal stress evolution trend in advance and avoid the risk of sudden deformation.

[0096] If the total center offset of the substrate-film composite is greater than or equal to the defined offset, the reduction amount of the critical cooling rate is determined based on the total center offset of the substrate-film composite, thereby reducing the critical cooling rate. The interval between collecting center information of the substrate-film composite is shortened based on the total center offset of the substrate-film composite. After adjustment, if the increment of the total center offset of the substrate-film composite is greater than or equal to the defined increment within the defined time, the critical cooling rate is continuously reduced, and a second-stage warning is issued for the cooling process of the substrate-film composite. If the increment of the total center offset of the substrate-film composite is not greater than or equal to the defined increment, the cooling rate is maintained during the monitoring stage.

[0097] The total center offset increment refers to the increase in the total center offset of the substrate-film composite within a defined time period; the defined increment refers to the upper limit of the total center offset increment preset in the database.

[0098] The defined duration refers to the time period set after adjusting the critical cooling rate to continuously monitor whether the total center offset of the substrate-film composite still shows a significant increasing trend. This duration serves as an important time window for evaluating the effectiveness of cooling adjustment measures and determining whether a higher-level warning has been triggered.

[0099] The second-stage early warning mechanism is a special early warning mechanism for the substrate-film composite during the cooling rate maintenance phase. It increases the data acquisition frequency to the highest system capacity (e.g., once every 20 milliseconds) to achieve near real-time monitoring. Combined with high-resolution thermal imaging or stress field imaging, it provides key visual monitoring of high-risk areas.

[0100] The monitoring parameters of the substrate-film composite are switched twice, maintaining the cooling rate during the cooling phase until the cooling rate is reduced at a uniform rate.

[0101] The monitoring parameters of the substrate-thin film composite were switched twice, and the specific process was as follows:

[0102] During the stage of uniformly slowing down the cooling rate, the abnormal state of the substrate-film composite is monitored by dual-wavelength laser of the monitoring device and defined sampling frequency. The center information of the substrate-film composite is collected at preset intervals. The size of the identification window is determined by obtaining the data confidence index of the monitoring device, thereby identifying the center coordinates of the substrate-film composite and determining whether there is a center coordinate deviation.

[0103] If there is no center coordinate deviation, continue monitoring the stage of uniformly slowing down the cooling rate;

[0104] If there is a center coordinate deviation, determine whether it is an invalid center coordinate deviation. If it is an invalid center coordinate deviation, continue to monitor the stage of uniformly slowing down the cooling rate.

[0105] If it is an effective center deviation, the total center offset of the substrate-film composite is obtained and compared with the defined offset. If the total center offset of the substrate-film composite is less than the defined offset, it is marked as an allowable deviation. At the same time, the rising rate of the total center offset of the substrate-film composite is analyzed. If the rising rate of the total center offset of the substrate-film composite is less than the preset rising rate of the defined center offset in the database, the uniformly slowing down cooling rate stage is continuously monitored. If the rising rate of the total center offset of the substrate-film composite is greater than or equal to the rising rate of the defined center offset, the second rate of change reduction is obtained, and the rate of change of the critical cooling rate is reduced and adjusted to update the cooling constraint conditions of the substrate-film composite. The uniformly slowing down cooling rate stage is continuously monitored.

[0106] The setting where the second rate of change decreases more than the first rate of change is a result of comprehensively considering multiple factors, including the increased sensitivity of the thin film structure to changes in thermal stress in the later stages of cooling, the intensified hysteresis effect of the material's thermal response, the gradual narrowing of the system's adjustment space, and the significantly increased requirements for the precision of the final thermal field control. Specifically: In the later stages of cooling, the stress concentration effect caused by the difference in the coefficients of thermal expansion between different materials in the substrate-thin film composite structure becomes more significant. Small temperature differences may lead to abrupt changes in nonlinear strain, or even trigger crack propagation or interface delamination risks. As the system gradually approaches the ambient temperature, the heat conduction rate decreases, and the response of temperature control to fine-tuning gradually delays. The coupling hysteresis between the adjustment command and the actual thermal behavior becomes more prominent, requiring fine-tuning through smaller rate of change increments. At the same time, the thermal field adjustment window in the tail end of cooling is limited by the accumulated residual stress and structural deformation path, narrowing in space and compressing in time, significantly reducing the tolerance for control errors. In addition, the accuracy of the final temperature directly affects the deposition quality, film density, and compatibility with subsequent processes, placing higher demands on temperature control accuracy.

[0107] If the total center offset of the substrate-film composite is greater than or equal to the defined offset, the reduction in the critical cooling rate is determined based on the total center offset of the substrate-film composite, thereby reducing the critical cooling rate. The interval between collecting center information of the substrate-film composite is shortened based on the total center offset of the substrate-film composite. After adjustment, if the total center offset of the substrate-film composite is still greater than or equal to the defined offset, the critical cooling rate is set to the minimum cooling rate, and a third-stage warning is issued for the cooling process of the substrate-film composite. If the total center offset of the substrate-film composite is not greater than or equal to the defined offset, the uniform slowing down of the cooling rate stage is continuously monitored.

[0108] Continuously monitor the cooling rate reduction phase until the substrate-film composite reaches the preset target temperature.

[0109] The third-stage warning is a special warning mechanism for the substrate-film composite during the stage of uniformly slowing down the cooling rate. The third-stage warning can also trigger post-cooling treatment processes, such as the slow-release heat preservation stage or specific interface strengthening operation recommendations, to extend to the closed loop of subsequent process treatment.

[0110] like Figure 2 The diagram shown is a structural diagram of a temperature control system for a CVD (Chemical Vapor Deposition) equipment. This system may include the following modules: a constraint optimization module, an abnormal state monitoring module, a temperature control optimization module, and a database.

[0111] A database that stores parameters involved in the temperature control system of CVD chemical vapor deposition equipment.

[0112] Figure 4 This is a schematic diagram of the cooling process monitoring provided in this embodiment of the invention. Based on the cooling transition curve, precise temperature control is implemented. During the cooling process, the abnormal state of the substrate-film composite is continuously monitored, and the existence of effective deviations in the center coordinates is identified. If an effective deviation exists, the total center offset and its rate of increase are further analyzed to optimize the cooling constraints. Simultaneously, different levels of early warning responses are triggered based on the severity of the total center offset. If the deviation is invalid or within acceptable limits, the cooling continues to be controlled according to the original cooling constraints. When the temperature drops to the preset target value and no significant abnormality is detected, the process ends. The overall process realizes a fully adaptive temperature control mechanism from thermodynamic modeling and temperature control constraint construction to deviation feedback regulation and closed-loop optimization.

[0113] Figure 5 The temperature control parameter configuration interface diagram provided in this embodiment of the invention has the core function of allowing operators to accurately define temperature-related parameters during the thin film deposition process. The interface includes a substrate selection module, a reaction gas selection module, a control mode selection module, a temperature threshold setting area for PID parameter adjustment, a temperature sampling and sensor setting area, a temperature region setting module, and an anomaly configuration module. Clicking "more" allows for the configuration of more comprehensive parameters.

[0114] Figure 6 The equipment monitoring interface diagram provided in this embodiment of the invention serves to enable operators to fully grasp the working status of each system of the equipment and promptly detect abnormalities. This interface includes parameters such as real-time heating zone temperature, substrate temperature, and chamber pressure. By clicking the details option, users can observe the change curves of these parameters. It also includes parameter calibration prompts and a function module that displays the current reaction progress in real time, thereby ensuring that the temperature parameter settings meet process requirements and providing a stable temperature environment for thin film deposition.

[0115] The above embodiments can be implemented, in whole or in part, by software, hardware (such as circuits), firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, all or part of the flow or function according to the embodiments of the present invention is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device.

[0116] It should be understood that, in various embodiments of the present invention, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0117] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the devices, apparatuses, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0118] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A temperature control method for a CVD (Chemical Vapor Deposition) equipment, characterized in that, The method includes: Step 1: Thin film deposition is performed on the substrate using a CVD (Chemical Vapor Deposition) device. After deposition, a substrate-film composite is obtained. The thermodynamic characteristics of the substrate and film are analyzed to determine the initial cooling constraints of the substrate-film composite. Temperature parameters during the film deposition process are collected and analyzed to optimize the initial cooling constraints of the substrate-film composite, thereby obtaining the initial cooling constraints of the substrate-film composite. The initial cooling constraints include the critical cooling rate and the rate of change of the critical cooling rate. Step 2: Based on the cooling constraint, a cooling transition curve of the substrate-film composite is generated. The CVD chemical vapor deposition equipment controls the temperature of the substrate-film composite during the cooling process based on the cooling transition curve and monitors the abnormal state of the substrate-film composite during the cooling process. Step 3: Collect and analyze the center coordinates of several physical detection points of the substrate-film composite during the cooling process. When an effective center shift is detected, determine whether to trigger a phased warning based on the total shift and the rate of increase, and adjust the critical cooling rate and the rate of change in real time to optimize the temperature control of the substrate-film composite until the temperature of the substrate-film composite is reduced to the target temperature. The monitoring of abnormal states of the substrate-film composite during the cooling process specifically refers to monitoring abnormal states of the substrate-film composite during the stages of uniformly increasing the cooling rate, maintaining the cooling rate, and uniformly decreasing the cooling rate. The center coordinates of several physical detection points of the substrate-film composite during the cooling process are collected and analyzed to optimize the temperature of the substrate-film composite, thereby determining whether to issue an early warning for the cooling process of the substrate-film composite. The cooling transition curve of the substrate-film composite includes a uniformly increasing cooling rate stage, a cooling rate holding stage, and a uniformly decreasing cooling rate stage. The uniformly increasing cooling rate stage refers to increasing the cooling rate of the substrate-film composite based on the critical cooling rate change rate of the substrate-film composite until the cooling rate of the substrate-film composite increases to the critical cooling rate. The cooling rate maintenance stage refers to cooling the substrate-film composite based on its critical cooling rate. The uniformly slowed-down cooling rate stage refers to the stage where the cooling rate of the substrate-film composite is reduced uniformly based on the critical cooling rate change rate of the substrate-film composite until the cooling rate of the substrate-film composite is reduced to the target cooling rate, and then the substrate-film composite is cooled at the target cooling rate until the substrate-film composite reaches the preset target temperature.

2. The temperature control method for a CVD chemical vapor deposition equipment according to claim 1, characterized in that, The specific process for determining the initial cooling constraint conditions for the substrate-film composite is as follows: The thermodynamic characteristics of the substrate and the thin film were analyzed separately to obtain the thermodynamic characteristic index of the substrate and the thermodynamic characteristic index of the thin film. Based on the thermodynamic characteristic index of the substrate, the critical cooling rate of the substrate and the rate of change of the critical cooling rate of the substrate are determined. Based on the thermodynamic characteristic index of the thin film, the critical cooling rate and the rate of change of the critical cooling rate of the thin film are determined. The minimum value between the critical cooling rate of the substrate and the critical cooling rate of the thin film is selected as the critical cooling rate in the initial cooling constraint. The minimum of the critical cooling rate change of the substrate and the critical cooling rate change of the thin film is selected as the critical cooling rate change in the initial cooling constraint.

3. The temperature control method for a CVD chemical vapor deposition equipment according to claim 1, characterized in that, The initial cooling constraint conditions for the substrate-film composite were optimized, and the specific optimization process is as follows: After the deposition process is completed, a temperature deviation retrospective analysis of the deposition process is initiated. The measured temperature at each sampling time point during the thin film deposition process of the substrate is analyzed against the preset process temperature, and the total temperature deviation value is obtained. The total temperature deviation is compared with the preset allowable deviation range. If the total temperature deviation falls within the allowable deviation range, the initial cooling constraint is directly used as the cooling constraint for the substrate-film composite. If the total temperature deviation value is not within the allowable range of deviation value, then based on the total temperature deviation value, the thermodynamic characteristic index of the thin film is reduced, the critical cooling rate of the thin film and the rate of change of the critical cooling rate of the thin film are updated, thereby optimizing the initial cooling constraint condition. After optimization, it is marked as the cooling constraint condition of the substrate-thin film composite. The cooling constraint includes the critical cooling rate and the rate of change of the critical cooling rate.

4. The temperature control method for a CVD chemical vapor deposition equipment according to claim 3, characterized in that, The specific analysis method for the aforementioned thermodynamic characteristic index is as follows: Thermodynamic characteristics include the coefficient of thermal expansion, the elastic limit strain rate, and the thermal diffusivity; Based on the influence relationship between the coefficient of thermal expansion, the elastic limit strain rate and the thermal diffusivity on the thermodynamic characteristic index, the corresponding boundary values ​​of the coefficient of thermal expansion, the elastic limit strain rate and the thermal diffusivity are assigned respectively. By assigning weighted proportional values, the coefficient of thermal expansion, the elastic limit strain rate, and the thermal diffusivity are given different effects on the thermodynamic characteristic index; A thermodynamic characteristic index is derived by integrating the defined values ​​and weighted ratios of the coefficient of thermal expansion, the elastic limit strain rate, and the thermal diffusivity. Specifically, the integration process involves: allocating the ratio between the defined coefficient of thermal expansion and the defined coefficient of thermal expansion to the thermodynamic characteristic index using a weighted ratio of the coefficient of thermal expansion, thus determining the influence component of the coefficient of thermal expansion on the thermodynamic characteristic index; allocating the ratio between the elastic limit strain rate and the defined elastic limit strain rate to the thermodynamic characteristic index using a weighted ratio of the elastic limit strain rate, thus determining the influence component of the elastic limit strain rate on the thermodynamic characteristic index; and allocating the ratio between the thermal diffusivity and the defined thermal diffusivity to the thermodynamic characteristic index using a weighted ratio of the thermal diffusivity, thus determining the influence component of the thermal diffusivity on the thermodynamic characteristic index. All these influence components are then summarized to form the thermodynamic characteristic index.

5. The temperature control method for a CVD chemical vapor deposition equipment according to claim 1, characterized in that, The specific determination process for whether to issue an early warning for the cooling process of the substrate-film composite is as follows: During the uniform temperature increase and decrease rate phase, the abnormal state of the substrate-film composite is monitored by the dual-wavelength laser of the monitoring device and the defined sampling frequency. The information of each center of the substrate-film composite is collected at preset intervals. The size of the identification window is determined by the data confidence index of the monitoring device, thereby identifying the center coordinates of several physical detection points of the substrate-film composite and determining whether there is a center coordinate deviation. If there is no center coordinate deviation, the uniform rate of increase and decrease will be continuously monitored during the stage. If there is a center coordinate deviation, determine whether it is an invalid center coordinate deviation. If it is an invalid center coordinate deviation, continue to monitor the uniform temperature increase and decrease rate stage. If the deviation is not an invalid center coordinate deviation, it indicates that there is an effective center deviation. If it is an effective center deviation, the total center offset of the substrate-film composite is obtained and compared with the defined offset. If the total center offset of the substrate-film composite is less than the defined offset, it is marked as an allowable deviation. At the same time, the rising rate of the total center offset of the substrate-film composite is analyzed. If the rising rate of the total center offset of the substrate-film composite is less than the rising rate of the defined center offset, the uniform increase and decrease rate stage is continuously monitored. If the rising rate of the total center offset of the substrate-film composite is greater than or equal to the rising rate of the defined center offset, the decrease in the first rate of change is obtained, thereby reducing and adjusting the rate of change of the critical cooling rate, thereby updating the cooling constraint conditions of the substrate-film composite, and the uniform increase and decrease rate stage is continuously monitored. If the total center offset of the substrate-film composite is greater than or equal to the defined offset, the reduction in the critical cooling rate is determined based on the total center offset of the substrate-film composite, thereby reducing the critical cooling rate. The interval between collecting center information of the substrate-film composite is shortened based on the total center offset of the substrate-film composite. After adjustment, if the total center offset of the substrate-film composite is still greater than or equal to the defined offset, the critical cooling rate is set to the minimum cooling rate, and a first-stage warning is issued for the cooling process of the substrate-film composite. If the total center offset of the substrate-film composite is not greater than or equal to the defined offset, the uniformly increasing cooling rate stage is continuously monitored. The monitoring parameters of the substrate-film composite are switched by continuously monitoring the uniformly increasing and decreasing rate phase until the cooling rate is maintained. The invalid center coordinate deviation refers to the disordered direction of the center coordinate deviation of several physical detection points or the total center offset showing a step change but then showing a stable trend. The defined offset is used to characterize the upper limit of the total center offset of the substrate-film composite that is allowed.

6. The temperature control method for a CVD chemical vapor deposition equipment according to claim 5, characterized in that, The monitoring parameters for the switching substrate-film composite specifically refer to: During the cooling rate maintenance phase, the abnormal state of the substrate-film composite is monitored by a single-wavelength laser from the monitoring device and a preset normal acquisition frequency. The center information of the substrate-film composite is acquired at preset intervals. The size of the identification window is determined by obtaining the data confidence index of the monitoring device, thereby identifying the center coordinates of several physical detection points of the substrate-film composite and determining whether there is a center coordinate deviation. If there is no center coordinate deviation, continue monitoring to maintain the cooling rate during the phase. If there is a center coordinate deviation, determine whether it is an invalid center coordinate deviation. If it is an invalid center coordinate deviation, continue monitoring to maintain the cooling rate. If it is an effective center deviation, the total center offset of the substrate-film composite is obtained and compared with the defined offset. If the total center offset of the substrate-film composite is less than the defined offset, it is marked as an allowable deviation. At the same time, the rising rate of the total center offset of the substrate-film composite is analyzed. If the rising rate of the total center offset of the substrate-film composite is less than the rising rate of the defined center offset, the cooling rate holding phase is continuously monitored. If the rising rate of the total center offset of the substrate-film composite is greater than or equal to the rising rate of the defined center offset, the first rate reduction magnitude is obtained, thereby reducing and adjusting the critical cooling rate, thereby updating the cooling constraint conditions of the substrate-film composite, and the cooling rate holding phase is continuously monitored. If the total center offset of the substrate-film composite is greater than or equal to the defined offset, the reduction amount of the critical cooling rate is determined based on the total center offset of the substrate-film composite, thereby reducing the critical cooling rate. The interval between collecting center information of the substrate-film composite is shortened based on the total center offset of the substrate-film composite. After the adjustment is completed, if the increment of the total center offset of the substrate-film composite is greater than or equal to the defined increment within the defined time, the critical cooling rate is continuously reduced, and a second-stage warning is issued for the cooling process of the substrate-film composite. If the increment of the total center offset of the substrate-film composite is not greater than or equal to the defined increment, the cooling rate is maintained during the monitoring stage. The monitoring parameters of the substrate-film composite are switched twice, maintaining the cooling rate during the cooling phase until the cooling rate is reduced at a uniform rate.

7. The temperature control method for a CVD chemical vapor deposition equipment according to claim 6, characterized in that, The monitoring parameters of the secondary switching substrate-thin film composite are as follows: During the stage of uniformly slowing down the cooling rate, the abnormal state of the substrate-film composite is monitored by the dual-wavelength laser of the monitoring device and the defined sampling frequency. The center information of the substrate-film composite is collected at preset intervals. The size of the identification window is determined by the data confidence index of the monitoring device, thereby identifying the center coordinates of several physical detection points of the substrate-film composite and determining whether there is a center coordinate deviation. If there is no center coordinate deviation, continue monitoring the stage of uniformly slowing down the cooling rate; If there is a center coordinate deviation, determine whether it is an invalid center coordinate deviation. If it is an invalid center coordinate deviation, continue to monitor the stage of uniformly slowing down the cooling rate. If it is an effective center deviation, the total center offset of the substrate-film composite is obtained and compared with the defined offset. If the total center offset of the substrate-film composite is less than the defined offset, it is marked as an allowable deviation. At the same time, the rising rate of the total center offset of the substrate-film composite is analyzed. If the rising rate of the total center offset of the substrate-film composite is less than the rising rate of the defined center offset, the uniformly slowing down cooling rate stage is continuously monitored. If the rising rate of the total center offset of the substrate-film composite is greater than or equal to the rising rate of the defined center offset, the second rate of change reduction is obtained, and the rate of change of the critical cooling rate is reduced to adjust the cooling constraint conditions of the substrate-film composite. The uniformly slowing down cooling rate stage is continuously monitored. If the total center offset of the substrate-film composite is greater than or equal to the defined offset, the reduction in the critical cooling rate is determined based on the total center offset of the substrate-film composite, thereby reducing the critical cooling rate. The interval between collecting center information of the substrate-film composite is shortened based on the total center offset of the substrate-film composite. After adjustment, if the total center offset of the substrate-film composite is still greater than or equal to the defined offset, the critical cooling rate is set to the minimum cooling rate, and a third-stage warning is issued for the cooling process of the substrate-film composite. If the total center offset of the substrate-film composite is not greater than or equal to the defined offset, the uniform slowing down of the cooling rate stage is continuously monitored. Continuously monitor the cooling rate reduction phase until the substrate-film composite reaches the preset target temperature.

8. The temperature control method for a CVD chemical vapor deposition equipment according to claim 7, characterized in that, The data confidence index of the monitoring device is analyzed in the following process: Based on the thermodynamic characteristic index of the substrate-film composite, data confidence increments are matched from the database; The laser coherence degradation rate and imaging temperature sensitivity of the monitoring device were obtained. The temperature change rate of the substrate-film composite is obtained, and the defined temperature change rate of the substrate-film composite is matched according to the imaging temperature sensitivity of the monitoring device. The data confidence index is determined by distinguishing the degree of influence of the ratio between the laser coherence degradation rate and the defined laser coherence degradation rate, as well as the deviation between the temperature change rate and the defined temperature change rate, on the data confidence index. The different degrees of influence are summarized, and the influence of the data confidence increment on the data confidence index is also incorporated, thus obtaining the data confidence index of the monitoring device. The data confidence index of the monitoring device is an indicator used to quantitatively evaluate the reliability and accuracy of the data collected by the monitoring device.

9. A temperature control system for a CVD (Chemical Vapor Deposition) apparatus, wherein the temperature control system for the CVD apparatus applies the temperature control method for a CVD apparatus as described in any one of claims 1-8, characterized in that, The system includes: The constraint optimization module uses a CVD (chemical vapor deposition) device to perform thin film deposition on the substrate. After the deposition process is completed, a substrate-thin film composite is obtained. The thermodynamic characteristics of the substrate and the thin film are analyzed to determine the initial cooling constraint conditions of the substrate-thin film composite. Temperature parameters during the thin film deposition process are collected and analyzed to optimize the initial cooling constraint conditions of the substrate-thin film composite, thereby obtaining the cooling constraint conditions of the substrate-thin film composite. The abnormal state monitoring module generates a cooling transition curve of the substrate-film composite based on the cooling constraint conditions. The CVD chemical vapor deposition equipment controls the temperature of the substrate-film composite during the cooling process based on the cooling transition curve and monitors the abnormal state of the substrate-film composite during the cooling process. The temperature control optimization module collects and analyzes the center coordinates of several physical detection points of the substrate-film composite during the cooling process. When an effective center shift is detected, it determines whether to trigger a phased warning based on the total shift and the rate of increase, and adjusts the critical cooling rate and the rate of change in real time to optimize the temperature control of the substrate-film composite until the temperature of the substrate-film composite is reduced to the target temperature.

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