A method for controlling wafer temperature, electronic equipment, and dielectric.

Abstract

This invention discloses a wafer temperature control method, electronic device, and medium, relating to the field of semiconductor manufacturing technology. The method includes: acquiring temperature control parameters of a temperature sensor and a wafer; heating the wafer according to an initial heating power and acquiring the actual temperature of the temperature sensor during the heating process; determining the temperature measurement object during the heating process based on the actual temperature and the temperature increment threshold of the temperature sensor; when the temperature measurement object represents the wafer, adjusting the initial heating power according to the target temperature of the temperature sensor, and using the adjusted heating power to heat the wafer so that the wafer temperature reaches the target wafer temperature. This invention has the characteristics and advantages of improving the accuracy and consistency of wafer temperature control, improving process stability, and meeting process control requirements.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and more particularly to a method for controlling wafer temperature, an electronic device, and a computer-readable medium. Background Technology

[0002] In semiconductor manufacturing processes, heated degassing chambers are primarily used to remove moisture, impurities, and other contaminants adsorbed on the wafer surface, ensuring the quality of subsequent wafer processing and the yield of finished products. In actual production, heated degassing chambers typically undergo multiple cycles of "heating-holding-cooling," and the real-time temperature of the wafer during heating is used as the core feedback signal for closed-loop temperature control. Due to limitations in the internal process layout of the chamber (such as chamber sealing and heating component arrangement) and the requirement for no damage protection to the wafer surface, indirect contact temperature measurement has become the mainstream technical solution in the industry, and there is currently no mature direct temperature measurement method applicable to mass production.

[0003] The current mainstream indirect temperature measurement method involves setting up a wafer carrier device (such as a support frame, electrostatic chuck, quartz stage, etc.) with thermocouples installed in the heating and degassing chamber, placing the wafer to be heated on the wafer carrier device, and directly equating the temperature of the wafer carrier device measured by the thermocouples to the actual temperature of the wafer; or, based on process experience, a fixed temperature difference threshold is preset, and the temperature measured by the thermocouples is added to the preset fixed temperature difference threshold as the actual temperature of the wafer.

[0004] However, this temperature measurement scheme exhibits significant dynamic errors in multi-cycle heating mode, directly inducing the failure of the PID temperature control system: In the initial stage of the first heating cycle, both the wafer carrier and the wafer are at room temperature, and their thermal conductivity characteristics are relatively stable. The temperature measurement signal based on the fixed compensation value can still meet the control accuracy of the PID system. However, starting from the second cycle, due to the accumulation of residual heat from the previous heating process, the initial temperature of the wafer carrier will gradually increase, and the temperature rise is directly related to the number of cycles, the heat dissipation efficiency of the chamber, and the number of wafer batches. At this time, the fixed temperature difference compensation value cannot adapt to the gradually changing thermal boundary conditions. At the same time, the rate at which thermal equilibrium is established between the wafer carrier and the wafer also changes with the initial temperature difference, resulting in a continuous increase in the deviation between the temperature measured by the thermocouple and the actual temperature of the wafer.

[0005] More importantly, distorted temperature measurement signals can severely interfere with the core logic of PID temperature control: on the one hand, the initially high temperature of the wafer carrier device may be misjudged as the wafer approaching the target temperature, causing the PID system to reduce the heating power prematurely, resulting in under-adjustment of the actual wafer temperature. On the other hand, once thermal equilibrium is established, sudden changes in temperature measurement deviation can trigger reverse compensation of the PID system, causing wafer temperature overshoot or even overshoot. This not only reduces the uniformity of degassing effect and degassing heating rate of a single wafer, but also leads to the degradation of process consistency between batches of wafers, making it difficult to meet the stringent temperature control requirements of advanced processes for heating and degassing. Summary of the Invention

[0006] This invention aims to address, to a certain extent, one of the technical problems in related technologies. To this end, this invention provides a wafer temperature control method, an electronic device for executing the control method, and a computer-readable medium, which has the characteristics and advantages of improving the accuracy and consistency of wafer temperature control, enhancing process stability, and meeting the control requirements of multi-cycle heating and degassing processes.

[0007] To achieve the above objectives, as a first aspect of the present invention, a method for controlling wafer temperature is provided, wherein the control method includes: Acquire temperature control parameters for the temperature sensor and the wafer; wherein, the temperature control parameters include the preset initial heating power of the wafer, the temperature increment threshold of the temperature sensor, and the target temperature of the temperature sensor corresponding to the target temperature of the wafer; The wafer is heated according to the initial heating power, and the actual temperature of the temperature sensor during the heating process is obtained; The object to be measured during the heating process is determined based on the actual temperature and the temperature increment threshold of the temperature sensor. When the object being measured is a wafer, the initial heating power is adjusted according to the target temperature of the temperature sensor, and the wafer is heated using the adjusted heating power so that the temperature of the wafer reaches the target temperature.

[0008] Optionally, determining the temperature measurement object during the heating process based on the actual temperature and the temperature increment threshold of the temperature sensor includes: Obtain the initial temperature of the temperature sensor when heating begins; The temperature increment is determined based on the actual temperature and the initial temperature; When the temperature increment is greater than or equal to the temperature increment threshold, the object being measured is a wafer; When the temperature increment is less than the temperature increment threshold, the temperature measurement object is a wafer carrier device.

[0009] Optionally, the control method further includes a multi-cycle heating cycle adaptation step: Obtain the initial temperature of the temperature sensor corresponding to the start of each heating cycle, and the actual temperature of the temperature sensor corresponding to the heating process of each heating cycle; The temperature increment for each heating cycle is determined based on the actual temperature and initial temperature corresponding to each heating cycle. If the temperature increment of a heating cycle is greater than or equal to the temperature increment threshold, the temperature measurement object of that heating cycle is the wafer; When the temperature increment of a heating cycle is less than the temperature increment threshold, the temperature measurement object of that heating cycle is the wafer carrier device.

[0010] Optionally, the temperature increment threshold is the same for each heating cycle.

[0011] Optionally, when the temperature measurement object represents a wafer, adjusting the initial heating power according to the target temperature of the temperature sensor, and using the adjusted heating power to heat the wafer so that the wafer temperature reaches the target wafer temperature, includes: When the actual temperature is less than the target temperature of the temperature sensor and the temperature rise rate under the heating power is less than or equal to the preset minimum temperature rise rate, the target temperature of the temperature sensor and the actual temperature are used as inputs to the PID algorithm to obtain the control signal. The initial heating power is adjusted according to the control signal to obtain the adjusted heating power; When the actual temperature is lower than the target temperature of the temperature sensor and the temperature rise rate at this heating power is greater than the preset minimum temperature rise rate, the heating power is maintained.

[0012] Optionally, the control method further includes: When the actual temperature is greater than the target temperature of the temperature sensor and the cooling rate under the heating power is less than or equal to the preset minimum cooling rate, the target temperature of the temperature sensor and the actual temperature of the temperature sensor are used as inputs to the PID algorithm to obtain the control signal. The initial heating power is adjusted according to the control signal to obtain the adjusted heating power; When the actual temperature is greater than the target temperature of the temperature sensor and the cooling rate at this heating power is greater than the preset minimum cooling rate, the heating power is maintained.

[0013] The initial heating power can be dynamically adjusted in real time according to the real-time temperature difference between the actual temperature and the target temperature of the temperature sensor. Specifically, it can be increased, decreased, or kept constant according to the PID control logic, without the need to manually set a fixed power level.

[0014] During PID control, the actual temperature of the temperature sensor is continuously collected and the real-time temperature difference is iteratively calculated until the actual temperature of the temperature sensor stabilizes and approaches and is maintained at the target temperature of the temperature sensor. Simultaneously, the wafer temperature is made to stabilize and reach the preset wafer target temperature, achieving precise temperature control without overshoot or undershoot.

[0015] Optionally, the PID control process is adapted to the waste heat accumulation scenario of multi-cycle heating. For the working condition where the initial temperature of the temperature sensor increases successively in each heating cycle, the PID control parameters maintain adaptive matching, without the need to readjust for different initial temperatures, ensuring consistent temperature control accuracy under multi-cycle working conditions.

[0016] Optionally, the temperature control parameters also include a preset temperature difference; the preset temperature difference is the same for each heating cycle; the sum of the preset temperature difference and the target temperature of the temperature sensor is the target temperature of the wafer.

[0017] Optionally, the control method further includes: When the object of temperature measurement represents a wafer carrier, the wafer is heated according to the initial heating power in the temperature control parameters, and the actual temperature of the temperature sensor during the heating process is obtained. The object to be measured during the heating process is determined based on the actual temperature and the temperature increment threshold of the temperature sensor.

[0018] The temperature measurement object determination step is repeated until the temperature increment reaches the corresponding temperature increment threshold, the temperature measurement object is switched to the wafer, and then the above-mentioned PID closed-loop temperature control process is started.

[0019] As a second aspect of the present invention, an electronic device is provided, comprising: One or more processors; A memory having stored one or more computer programs that, when executed by one or more processors, cause the one or more processors to implement the wafer temperature control method provided according to the first aspect of the invention.

[0020] Furthermore, as a third aspect of the present invention, a computer-readable medium is provided having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the wafer temperature control method provided in the first aspect of the present invention.

[0021] To address the technical problems in traditional indirect temperature measurement, such as the gradual increase in the initial temperature of the wafer carrier due to the accumulation of residual heat during multiple heating cycles, large errors in fixed temperature difference compensation, and the tendency for PID temperature control to overshoot and undershoot, as well as poor process consistency, this invention first obtains temperature control parameters such as the initial heating power of the wafer, the temperature increment threshold of the temperature sensor, and the target temperature of the temperature sensor corresponding to the target temperature of the wafer. These parameters are used to establish a stable heating and temperature measurement benchmark, adapting to dynamically changing thermal boundary conditions under multi-cycle operating conditions, ensuring accurate matching of heating requirements and temperature judgment criteria at different stages. Then, based on the preset initial heating power in the temperature control parameters, the wafer is subjected to open-loop heating, and the actual temperature during the open-loop heating process is obtained. The actual temperature and the temperature increment threshold are used to dynamically determine whether the current temperature measurement object is the wafer or the wafer carrier device, fundamentally avoiding the interference of initial temperature fluctuations caused by the accumulation of residual heat in the wafer carrier device, and accurately identifying key points where the thermocouple temperature is equivalent to the wafer temperature. When the temperature measurement object is a wafer, the closed-loop PID temperature control stage is entered. The heating power is adaptively adjusted based on the target temperature of the temperature sensor, so that the wafer temperature can be stably reached to the target wafer temperature, thereby achieving accurate control of the wafer temperature and improving process consistency.

[0022] These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and accompanying drawings. The preferred embodiments or means of the present invention will be shown in detail in conjunction with the accompanying drawings, but are not intended to limit the technical solutions of the present invention. In addition, each of these features, elements and components appearing in the following text and drawings is a plurality of, and different symbols or numbers are used for convenience of representation, but all represent parts with the same or similar construction or function. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings: Figure 1 A flowchart of a wafer temperature control method provided by the present invention; Figure 2 A flowchart illustrating one embodiment of step S130 of the control method provided by the present invention; Figure 3 A flowchart illustrating one embodiment of step S130 of the control method provided by the present invention; Figure 4 A flowchart illustrating one embodiment of step S140 of the control method provided by the present invention; Figure 5 A flowchart illustrating a complete implementation of step S140 of the control method provided by the present invention; Figure 6 A temperature diagram illustrating the changes of wafer temperature and thermocouple temperature over time during the process of determining temperature control parameters in the control method provided by the present invention. Figure 7A complete flowchart of a wafer temperature control method provided by the present invention; Figure 8 The experimental results of multi-cycle heating temperature control provided by this invention are shown in the figure. Figure 9 The experimental results of the 34th cycle of the multi-cycle heating temperature control provided by this invention are shown in the figure. Figure 10 A module diagram of an electronic device provided by the present invention; Figure 11 This invention provides a schematic diagram of a computer-readable medium.

[0024] Explanation of reference numerals in the attached figures Among them, 101 is the processor; 102 is the memory; 103 is the I / O interface; and 104 is the bus. Detailed Implementation

[0025] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described are intended to explain the present invention and should not be construed as limiting the invention.

[0026] The terms "an embodiment," "example," or "trademark" used in this specification refer to a particular feature, structure, or characteristic described in connection with the embodiment itself that may be included in at least one embodiment disclosed in this invention. The phrase "in an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0027] In ideal temperature measurement methods, both the desired heating object and the object of temperature measurement are the wafer. However, in practical applications, the wafer needs to be placed on a wafer carrier, and the temperature sensor indirectly measures the temperature; the object of temperature measurement is the wafer carrier. Throughout the heating process, the wafer carrier is heated synchronously with the wafer, which means that the temperature obtained by the temperature sensor in real time is not the true temperature of the wafer. Specifically, in the initial stage of heating, the wafer and the wafer carrier are heated simultaneously. At this time, the temperature collected by the thermocouple placed on the wafer carrier reflects the real-time temperature of the wafer carrier, not the wafer. Only after heating to a certain stage, when the temperatures of the wafer carrier and the wafer reach thermal equilibrium, does the temperature collected by the temperature sensor truly reflect the wafer temperature. Furthermore, during the repeated heating cycles, the wafer carrier accumulates residual heat. The correspondence between the temperature at the measurement point and the wafer temperature will change non-linearly and dynamically with the heating stage and the number of cycles. These factors combined result in the temperature sensor being unable to accurately and in real-time acquire the wafer temperature, and unable to provide accurate temperature feedback and control, leading to poor process repeatability and consistency, and failing to meet the requirements of multi-cycle heating processes.

[0028] In view of this, in order to solve the above problems, as a first aspect of the present invention, a method for controlling wafer temperature is provided, such as... Figure 1 As shown, the control method includes: In step S110, the temperature control parameters of the temperature sensor and the wafer are obtained; wherein, the temperature control parameters include the preset initial heating power of the wafer, the temperature increment threshold of the temperature sensor, and the target temperature of the temperature sensor corresponding to the target temperature of the wafer; In step S120, the wafer is heated according to the initial heating power, and the actual temperature of the temperature sensor during the heating process is obtained; In step S130, the object to be measured during the heating process is determined based on the actual temperature and the temperature increment threshold of the temperature sensor. In step S140, when the temperature measurement object represents a wafer, the initial heating power is adjusted according to the target temperature of the temperature sensor, and the wafer is heated using the adjusted heating power so that the temperature of the wafer reaches the target temperature of the wafer.

[0029] To address the technical problems of traditional indirect temperature measurement, such as the gradual increase in the initial temperature of the wafer carrier due to the accumulation of residual heat during multi-cycle heating, large errors in fixed temperature difference compensation, and the tendency for PID temperature control to overshoot and undershoot, as well as poor process consistency, this invention first obtains temperature control parameters such as the initial heating power of the wafer, the temperature increment threshold of the temperature sensor, and the target temperature of the temperature sensor corresponding to the target temperature of the wafer. These parameters are used to establish a stable heating and temperature measurement benchmark, adapting to dynamically changing thermal boundary conditions under multi-cycle operating conditions, ensuring accurate matching of heating requirements and temperature judgment criteria at different stages. Then, based on the initial heating power in the temperature control parameters, the wafer is subjected to open-loop heating, and the actual temperature during the open-loop heating process is obtained. The actual temperature and the temperature increment threshold are used to dynamically determine whether the current temperature measurement object is the wafer or the wafer carrier device, fundamentally avoiding the interference of initial temperature fluctuations caused by the accumulation of residual heat in the wafer carrier device, and accurately identifying key points where the thermocouple temperature is equivalent to the wafer temperature. When the temperature measurement object is a wafer, the closed-loop PID temperature control stage is entered. The heating power is adaptively adjusted based on the target temperature of the temperature sensor, so that the wafer temperature can be stably reached to the target wafer temperature, thereby achieving accurate control of the wafer temperature and improving process consistency.

[0030] Taking the cyclic heating process of the degassing chamber as an example, the wafer is placed on a wafer carrier. The wafer carrier is initially at room temperature, but residual heat gradually accumulates with each heating cycle. Therefore, in the initial heating and subsequent heating cycles, the thermocouples on the wafer carrier cannot reflect the wafer temperature in a timely and accurate manner, resulting in a lag in the temperature measurement signal or an unclear measurement target.

[0031] Because stable and accurate wafer temperature feedback is unavailable, closed-loop temperature control based on conventional indirect temperature measurement is prone to control deviations. During the cyclic process of continuously changing thermal states of the wafer carrier, the actual wafer temperature deviates from the target temperature, affecting degassing efficiency and process repeatability. As the number of cycles increases, the accumulation of residual heat in the wafer carrier gradually amplifies the temperature control deviation, ultimately making it difficult to meet temperature control requirements. Therefore, determining the actual temperature measurement object corresponding to the thermocouple's acquisition temperature is crucial throughout the entire temperature control process.

[0032] To determine the actual temperature-measuring object corresponding to the temperature collected by the temperature sensor, reduce temperature control deviation, and meet temperature control requirements, as an optional implementation of step S130, such as... Figure 2 As shown, determining the temperature measurement object during the heating process based on the actual temperature and the temperature increment threshold of the temperature sensor includes: In step S131, the initial temperature of the temperature sensor when heating begins is obtained; In step S132, the temperature increment is determined based on the actual temperature and the initial temperature; In step S133, if the temperature increment is greater than or equal to the temperature increment threshold, the object being measured is a wafer; In step S134, if the temperature increment is less than the temperature increment threshold, the temperature measurement object is a wafer carrier device.

[0033] Specifically, the following examples, combining the principles of heat conduction and the method for determining the temperature increment threshold, provide an embodiment for accurately determining the object to be measured.

[0034] Taking heat conduction during the heating process as an example. At the beginning of heating, the heating device heats the wafer. Part of the heat absorbed by the wafer is used to raise its own temperature, and the other part is transferred to the wafer carrier device in contact with it through heat conduction. In subsequent heating cycles, the wafer carrier device has accumulated residual heat. After the room-temperature wafer is placed in, the wafer carrier device first transfers heat to the wafer. The heat is rapidly conducted inside the wafer, causing the overall temperature of the wafer to rise. The temperatures of the wafer carrier device and the wafer gradually tend to balance over time. When the wafer is further heated to a temperature higher than that of the wafer carrier device, the heat flow direction reverses, and heat is transferred from the wafer to the wafer carrier device. According to the temperature control method of this invention, as the heating cycles gradually accumulate, the initial temperatures of each component of the wafer carrier device gradually accumulate and balance. The initial temperature measured by the temperature sensor gradually stabilizes, and the temperature control process throughout the cycle gradually approaches and eventually becomes essentially consistent, and the system enters a quasi-steady-state process.

[0035] The target temperature of the temperature sensor is obtained through experimental calibration: a TCWafer with multi-point thermocouples is used to test the wafer (for testing and calibration only, not for normal production), or an external infrared thermometer is used to directly acquire the actual temperature of the test wafer during heating. When the actual temperature of the test wafer has reached and stabilized at the target temperature, the actual temperature of the temperature sensor at this time is recorded; this temperature value is the target temperature of the temperature sensor. Similarly, the difference between the target wafer temperature and the target temperature of the temperature sensor is the preset temperature difference.

[0036] Extensive simulations and testing have verified that, under any cycle, when the difference between the actual temperature of the temperature sensor and its initial temperature in that cycle exceeds the temperature increment threshold, the temperature measured by the temperature sensor can be considered to accurately reflect the wafer temperature (or maintain only a fixed preset temperature difference with the wafer temperature). In this case, the object of temperature measurement is the wafer; conversely, the object is the wafer carrier. This temperature increment threshold is a value given based on simulation, experimentation, or mass production experience, designed to achieve a relative thermal equilibrium between the wafer carrier and the wafer temperature in each heating cycle, typically set at 10-15°C. It should be noted that the aforementioned temperature sensors include, but are not limited to, thermocouples and thermopile devices.

[0037] Similarly, in order to solve the problem of poor temperature consistency between different cycles and batches of wafers, this invention requires the determination of the object to be measured in each heating process.

[0038] For example, under the constraints of low-temperature and vacuum processes, it is necessary to perform step-by-step desorption and dynamic extraction on the same wafer to achieve more thorough degassing while avoiding high-temperature damage to the wafer. Another example is in multi-cycle heating processes. During the first round of heating, the wafer carrier temperature is too low, which can easily lead to insufficient wafer temperature and incomplete degassing. By the fifth round of heating, the wafer carrier has accumulated a large amount of residual heat, which can easily result in excessively high wafer temperature or even damage to the wafer.

[0039] In this type of multi-batch, multi-cycle heating process, residual heat continuously accumulates between the wafer carrier and the wafer, and the heat flow direction changes repeatedly, resulting in completely different thermal states in different heating cycles. If the temperature measurement object is only judged once at the initial stage of heating, it cannot adapt to the dynamically changing thermal states between each cycle, and problems such as inaccurate temperature measurement and large temperature control deviations will still occur. Therefore, as another optional implementation method for step S130, such as Figure 3 As shown, the control method further includes: In step S131, the initial temperature of the temperature sensor corresponding to the start of each heating cycle and the actual temperature of the temperature sensor corresponding to the heating process of each heating cycle are obtained. In step S132, the temperature increment for each heating cycle is determined based on the actual temperature and the initial temperature corresponding to each heating cycle. In step S133, if the temperature increment of a heating cycle is greater than or equal to the temperature increment threshold of that heating cycle, the temperature measurement object of that heating cycle is the wafer; In step S134, if the temperature increment of a heating cycle is less than the temperature increment threshold of that heating cycle, the temperature measurement object of that heating cycle is the wafer carrier device.

[0040] As explained above, in the process of using the TC Wafer to test the wafer to determine the target temperature of the temperature sensor (i.e., the preset temperature difference between the wafer target temperature and the temperature sensor target temperature), this preset temperature difference remains consistent across all cycles, ensuring that the target temperature of the temperature sensor is consistent across batches and heating cycles. Therefore, using the same preset temperature difference for each heating cycle simplifies the control logic, improves process consistency, and better meets the precise control requirements of the current multi-cycle heating and degassing process.

[0041] Once it is determined that the temperature sensor is measuring a wafer, closed-loop precise temperature control can be performed. As an optional implementation of step S140, such as... Figure 4 As shown, when the temperature measurement object represents a wafer, adjusting the initial heating power according to the target temperature of the temperature sensor, and using the adjusted heating power to heat the wafer so that the wafer temperature reaches the target wafer temperature, includes: In step S141, when the actual temperature is less than the target temperature of the temperature sensor and the temperature rise rate under the heating power is less than or equal to the preset minimum temperature rise rate, the target temperature of the temperature sensor and the actual temperature are used as inputs to the PID algorithm to obtain the control signal. In step S142, the initial heating power is adjusted according to the control signal to obtain the adjusted heating power; In step S143, when the actual temperature is less than the target temperature of the temperature sensor and the temperature rise rate under the heating power is greater than the preset minimum temperature rise rate, the heating power is maintained.

[0042] It's important to note that while the temperature sensor is identified as measuring the wafer, this only indicates that the system has entered a stable thermal state. It doesn't mean the temperature measured by the sensor can be directly equated to the actual wafer temperature. Typically, due to limitations in sensor installation location and layout, there's a fixed difference between the temperature measured by the sensor and the actual wafer temperature. In actual production, the actual wafer temperature cannot be directly obtained, but the target wafer temperature is a clearly defined target value that process control aims to achieve. Under the aforementioned stable environment, because the wafer temperature and sensor temperature maintain a fixed difference, PID closed-loop regulation can be performed based on the sensor's target temperature, corresponding to the wafer's target temperature, ultimately bringing the actual wafer temperature to the target wafer temperature.

[0043] It's important to clarify that PID control is a closed-loop regulation method that uses the target temperature from the sensor as feedback to perform proportional, integral, and derivative calculations on the heating power. The initial heating power is a fixed power or power curve determined through actual production experience. At the start of the heating process, a fixed power is used, and during the heating process, the heating power is adaptively adjusted using PID control. The wafer is then heated using the adjusted power, and further adaptive regulation is achieved through PID control based on this adjusted power, requiring no manual intervention.

[0044] Similarly, as another complete implementation of step S140, such as Figure 5 As shown, the complete steps of the closed-loop precise temperature control are as follows: In step S141, when the actual temperature is less than the target temperature of the temperature sensor and the temperature rise rate under the heating power is less than or equal to the preset minimum temperature rise rate, the target temperature of the temperature sensor and the actual temperature are used as inputs to the PID algorithm to obtain the control signal. In step S142, the initial heating power is adjusted according to the control signal to obtain the adjusted heating power; In step S143, when the actual temperature is less than the target temperature of the temperature sensor and the temperature rise rate under the heating power is greater than the preset minimum temperature rise rate, the heating power is maintained. In step S144, when the actual temperature is greater than the target temperature of the temperature sensor and the cooling rate under the heating power is less than or equal to the preset minimum cooling rate, the target temperature of the temperature sensor and the actual temperature of the temperature sensor are used as inputs to the PID algorithm to obtain the control signal. In step S145, the initial heating power is adjusted according to the control signal to obtain the adjusted heating power; In step S146, if the actual temperature is greater than the target temperature of the temperature sensor and the cooling rate under the heating power is greater than the preset minimum cooling rate, the heating power is maintained.

[0045] The logic of the entire closed-loop precise temperature control is as follows: real-time monitoring of the actual temperature of the temperature sensor, combined with PID algorithm for closed-loop control. When the actual temperature is lower than the target temperature of the temperature sensor and the temperature rise rate under the current heating power is less than or equal to the preset minimum temperature rise rate (i.e., the current heat cannot offset the system's heat loss, the temperature rise is too slow, and it is difficult to quickly approach the target temperature), the PID algorithm outputs a control signal to increase the heating power; when the actual temperature is lower than the target temperature of the temperature sensor and the temperature rise rate is greater than the preset minimum temperature rise rate (i.e., the current heat can offset the system's heat loss, the temperature rise rate is stable, there is sufficient temperature margin, there is no risk of overshoot, and the temperature can slowly rise to approach the target), the current heating power is maintained; when the actual temperature is higher than the target temperature of the temperature sensor and the cooling rate under the current heating power is less than or equal to the preset minimum cooling rate (i.e., the current cooling efficiency is insufficient, the heat dissipates too slowly, it is difficult to quickly return to the target temperature, and there is a risk of overshooting and continued high temperature), the PID algorithm outputs a control signal to decrease the heating power; when the actual temperature is higher than the target temperature of the temperature sensor and the cooling rate is greater than the preset minimum cooling rate (i.e., the current cooling rate is gentle, the temperature drops smoothly, there is a reasonable margin with the target temperature, and there is no risk of undershoot), the current heating power is maintained. The PID closed-loop control method described above can ensure that the wafer temperature reaches the target wafer temperature stably, thereby improving the temperature consistency and process stability of the entire heating and degassing process.

[0046] Similarly, the PID control process is adapted to the waste heat accumulation scenario of multi-cycle heating. For the working condition where the initial temperature of the temperature sensor increases successively in each heating cycle, the PID control parameters maintain adaptive matching and do not need to be readjusted for different initial temperatures, ensuring consistent temperature control accuracy under multi-cycle working conditions.

[0047] As explained above, due to limitations in sensor installation location and layout, there is a fixed difference between the temperature acquired by the temperature sensor and the actual wafer temperature. In other words, the fixed difference between the wafer target temperature and the temperature sensor target temperature is the preset temperature difference. When the system reaches the aforementioned stable state, this preset temperature difference remains constant, and the preset temperature difference is the same for each heating cycle. There is no need to recalibrate the temperature compensation value for each heating cycle; the wafer target temperature can be accurately calculated from the temperature sensor target temperature based on the fixed preset temperature difference. This ensures the accuracy and consistency of wafer temperature control across multiple cycles and batches, simplifies the temperature control logic, and improves process stability.

[0048] The following detailed description of the process for determining the temperature control parameters provided by the present invention, with reference to specific embodiments, is provided in detail.

[0049] like Figure 6 As shown, in the first heating cycle, open-loop heating is performed using a pre-set heating power P or power curve P(t) that allows the wafer to gradually heat up to the target temperature Twg (e.g., 200°C). When the wafer temperature is confirmed to have reached and stabilized at the target temperature Twg by a TCwafer with a thermocouple or by external infrared thermometry, the stable temperature value measured by the thermocouple at this time is recorded. This value is the target temperature of the temperature sensor (target thermocouple temperature Tcg). Tcg is the set value that the thermocouple should reach under ideal conditions (when directly reflecting the wafer temperature). Different target wafer temperatures Twg will result in different target thermocouple temperatures Tcg, but for the structure of this invention, Twg and Tcg are basically maintained at a relatively stable difference, that is, Twg-Tcg ≈ Co (constant / preset temperature difference). This difference can be determined and recorded through multiple pre-experiments and then transmitted to the subsequent temperature control system.

[0050] Perform N consecutive heating cycles (N is large enough to make the system approach quasi-steady state). Record the initial temperature Tcn of the thermocouple. Then, heat the thermocouple again using the same fixed power P or power curve P(t). Analysis of the thermocouple temperature curve reveals that when the thermocouple temperature rises from Tcn by a certain increment (temperature increment threshold, e.g., 10℃, determined through experimental data optimization), its temperature change rate changes. This indicates that the thermocouple's temperature measurement target can now be switched from the fixed wafer carrier to the wafer itself, effectively reflecting the wafer temperature.

[0051] Furthermore, during temperature control, when the temperature measurement object is a wafer carrier device, an open-loop control method is used to continuously heat the wafer. As another embodiment of the present invention, such as... Figure 7 As shown. The control method further includes: In step S150, when the temperature measurement object represents a wafer carrier, the wafer is heated according to the initial heating power in the temperature control parameters, and the actual temperature of the temperature sensor during the heating process is obtained.

[0052] Figure 7The temperature control method provided by this invention is described in detail. It first employs open-loop heating, followed by closed-loop precise control. When the temperature measurement target is not a wafer, open-loop heating rapidly raises the system temperature, allowing the wafer carrier and the wafer to quickly enter a thermally stable state. Simultaneously, the temperature measurement target is continuously identified, avoiding ineffective closed-loop adjustments during periods of inaccurate temperature measurement. Once the temperature measurement target is confirmed to be a wafer, the system switches to closed-loop precise temperature control, using the target temperature of the temperature sensor as a reference to stably control the wafer temperature. This invention ensures heating efficiency while avoiding temperature control deviations caused by unclear temperature measurement targets or temperature signal fluctuations, significantly improving temperature stability and process consistency in multi-cycle, multi-batch wafer heating processes.

[0053] Specifically, the experimental results of multi-cycle heating temperature control with a target wafer temperature of Twg=200℃ are shown in the figure below. Figure 8 As shown in the figure. The target temperature of the temperature sensor (the target temperature of the thermocouple) was determined to be Tcg=190℃ through preliminary experiments, and the preset temperature difference Co=10℃. Figure 8 In the diagram, two curves represent the temperature measurements of the thermocouples corresponding to the upper and lower wafers within the cavity. Experimental results show that the system can quickly enter a quasi-steady state within 3-5 cycles, effectively suppressing temperature accumulation in various parts of the wafer carrier and rapidly reaching dynamic equilibrium. In each cycle, by determining the temperature increment threshold C (C=10℃ in this cycle experiment), erroneous feedback caused by thermocouple measurements not on the wafer itself during the initial heating stage was successfully avoided, ensuring that the PID closed-loop control is always based on the correct temperature signal and providing real-time feedback on the wafer temperature. Ultimately, the wafers in each cycle stage can be accurately heated to the target temperature Twg=200℃ with good repeatability. This temperature value has been verified by sampling the wafers outside the cavity using an infrared thermometer and comparing it with the calibration results of the first cycle, confirming the accuracy of the method.

[0054] The thermocouple temperature measurement results for the 34th cycle are as follows: Figure 9 As shown, with Tcn=150℃, the wafer is first heated to Tcn+C=160℃ using a fixed full power. Then, PID control (closed-loop control) is activated to continue heating to the thermocouple target temperature Tcg=190℃. At this point, the actual target temperature of the wafer, Twg=200℃, is confirmed by monitoring with an external infrared thermometer. The fixed temperature difference between the wafer and the thermocouple target temperature meets the preset requirements. Figure 9 The two curves in the figure correspond to the two wafers placed one above the other in the chamber. As can be seen from the figure, the target temperatures of the thermocouples corresponding to the two wafers are basically consistent, which further verifies that the control method of the present invention has good temperature consistency and can effectively ensure the process stability and consistency of heating multiple wafers at the same time.

[0055] After adopting the wafer temperature control method provided by the present invention, the wafer temperature uniformity under the wafer carrier device, measured by a special TC Wafer test wafer, is controlled within 200±5℃, and the surface temperature uniformity of the wafer during the temperature maintenance stage can also meet the process requirements.

[0056] The following describes the operational process of applying the wafer temperature control method according to the present invention in actual production.

[0057] Step 1: Wafer loading and preparation stage. The robotic arm places the room-temperature wafer onto the support fingers of the carrier device, closes the cavity inlet, evacuates to the required process level, and then introduces a constant flow of inert gas (such as nitrogen or argon) to maintain a dynamically balanced micro-positive pressure environment (such as 7 torr).

[0058] Step 2: Heating and Temperature Maintenance Stage. The thermocouple temperature control target is set to a pre-calibrated Tcg = Twg - Co. Before each heating cycle begins, the current thermocouple temperature value Tcn is read and recorded. The upper and lower lamp arrays are activated, and the wafer is heated with a pre-calibrated fixed power P or power curve P(t). The thermocouple temperature Tc is monitored in real time. When Tc - Tcn ≥ temperature increment threshold C, the system determines that the temperature measured by the thermocouple mainly originates from the lower surface of the support pillar and can reliably reflect the temperature change trend of the wafer, immediately triggering a temperature control strategy switch. A PID control algorithm is used to dynamically adjust the lamp array heating power based on the real-time feedback Tc from the thermocouples, heating and raising the thermocouple temperature to maintain it at Tcg. Under this steady state, the actual temperature of the wafer stabilizes at the required target temperature Twg, where Twg = Tcg + Co (preset temperature difference).

[0059] Step 3: Incubation, Cooling, and Wafer Transfer Stage. Maintain the target temperature for the specified time to ensure degassing. After completion, stop heating, evacuate the chamber to a high vacuum, open the outlet, and transfer the wafer to the next process chamber.

[0060] Step 4: Cavity Reset Stage. Close the outlet, fill the cavity with gas to atmospheric pressure, open the inlet, and prepare to receive the next wafer to begin a new cycle.

[0061] Furthermore, through extensive simulations and testing, the inventors of this application discovered that after the system enters a quasi-steady state, the initial temperature plus the temperature increment threshold (Tcn+C) acquired by the temperature sensors in each heating cycle will eventually converge to a stable value. Therefore, under any heating cycle, the temperature of the object being measured and the wafer temperature can be determined by judging whether the actual temperature of the temperature sensor reaches or exceeds this stable value. When the actual temperature exceeds or reaches this stable value, it indicates that the current object being measured is the wafer, and the measured actual temperature can truly reflect the target temperature of the wafer (or has a fixed difference from the target temperature of the wafer); otherwise, the object being measured is the wafer carrier device.

[0062] This method still successfully avoids erroneous feedback caused by thermocouple measurements of non-wafer components during the initial heating phase, ensuring that the PID closed-loop control is always based on the correct temperature signal and provides real-time feedback of the wafer temperature. Applying this method to the aforementioned "experimental test of multi-cycle heating temperature control with a target wafer temperature Twg=200℃," the wafer was accurately heated to the target temperature Twg=200℃ in each cycle stage with good repeatability. This temperature value was verified by sampling the wafer outside the cavity using an infrared thermometer and comparing it with the calibration results of the first cycle, confirming the accuracy of the method.

[0063] As a second aspect of the present invention, an electronic device is provided, such as... Figure 10 As shown, it includes: One or more processors 101; The memory 102 stores one or more computer programs that, when executed by the one or more processors 101, cause the one or more processors 101 to implement the control method provided according to the first aspect of the invention.

[0064] The tool may also include one or more I / O interfaces 103 connected between the processor 101 and the memory 102, configured to enable information interaction between the processor 101 and the memory 102.

[0065] The processor 101 is a device with data processing capabilities, including but not limited to a central processing unit 101 (CPU); the first memory 102 is a device with data storage capabilities, including but not limited to random access memory 102 (RAM, more specifically SDRAM, DDR, etc.), read-only memory 102 (ROM), electrically erasable programmable read-only memory 102 (EEPROM), and flash memory (FLASH); the I / O interface 103 (read-write interface) is connected between the processor 101 and the memory 102, enabling information interaction between the processor 101 and the memory 102, including but not limited to a data bus 104 (Bus).

[0066] In some embodiments, the processor 101, memory 102, and I / O interface 103 are interconnected via bus 104, and thus connected to other components of the computing device.

[0067] Furthermore, as a third aspect of the present invention, a computer-readable medium is also provided having a computer program stored thereon, such as... Figure 11 As shown, when the computer program is executed by the processor, it implements the control method provided by the first aspect of the present invention.

[0068] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. Accordingly, the computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can implement the methods of any of the above embodiments. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0069] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments above. Any modifications that do not depart from the functional and structural principles of the present invention will be included within the scope of the claims.

Claims

1. A method for controlling wafer temperature, characterized in that, The control method includes: The temperature control parameters of the temperature sensor and the wafer are obtained; wherein, the temperature control parameters include the initial heating power preset for the wafer, the temperature increment threshold of the temperature sensor, and the target temperature of the temperature sensor corresponding to the target temperature of the wafer; the temperature increment threshold is a value that allows the wafer carrier device and the wafer temperature to reach a relative thermal equilibrium in each heating cycle; The wafer is heated according to the initial heating power, and the actual temperature of the temperature sensor during the heating process is obtained; Determining the temperature measurement object during the heating process based on the actual temperature and the temperature increment threshold of the temperature sensor includes: Obtain the initial temperature of the temperature sensor when heating begins; The temperature increment is determined based on the actual temperature and the initial temperature; When the temperature increment is greater than or equal to the temperature increment threshold, the object being measured is a wafer; When the temperature increment is less than the temperature increment threshold, the object being measured is a wafer carrier device; When the object being measured is a wafer, the initial heating power is adjusted according to the target temperature of the temperature sensor, and the wafer is heated using the adjusted heating power so that the temperature of the wafer reaches the target temperature.

2. The control method according to claim 1, characterized in that, The control method further includes: Obtain the initial temperature of the temperature sensor corresponding to the start of each heating cycle, and the actual temperature of the temperature sensor corresponding to the heating process of each heating cycle; The temperature increment for each heating cycle is determined based on the actual temperature and initial temperature corresponding to each heating cycle. If the temperature increment of a heating cycle is greater than or equal to the temperature increment threshold, the temperature measurement object of that heating cycle is the wafer; When the temperature increment of a heating cycle is less than the temperature increment threshold, the temperature measurement object of that heating cycle is the wafer carrier device.

3. The control method according to claim 2, characterized in that, The temperature increment threshold is the same for each heating cycle.

4. The control method according to claim 1, characterized in that, When the object being measured represents a wafer, adjusting the initial heating power according to the target temperature of the temperature sensor, and using the adjusted heating power to heat the wafer so that the wafer reaches the target temperature, includes: When the actual temperature is less than the target temperature of the temperature sensor and the temperature rise rate under the heating power is less than or equal to the preset minimum temperature rise rate, the target temperature of the temperature sensor and the actual temperature are used as inputs to the PID algorithm to obtain the control signal. The initial heating power is adjusted according to the control signal to obtain the adjusted heating power; When the actual temperature is lower than the target temperature of the temperature sensor and the temperature rise rate at this heating power is greater than the preset minimum temperature rise rate, the heating power is maintained.

5. The control method according to claim 4, characterized in that, The control method further includes: When the actual temperature is greater than the target temperature of the temperature sensor and the cooling rate under the heating power is less than or equal to the preset minimum cooling rate, the target temperature of the temperature sensor and the actual temperature of the temperature sensor are used as inputs to the PID algorithm to obtain the control signal. The initial heating power is adjusted according to the control signal to obtain the adjusted heating power; When the actual temperature is greater than the target temperature of the temperature sensor and the cooling rate at this heating power is greater than the preset minimum cooling rate, the heating power is maintained.

6. The control method according to any one of claims 1 to 5, characterized in that, The temperature control parameters also include a preset temperature difference; The preset temperature difference is the same for each heating cycle; The sum of the preset temperature difference and the target temperature of the temperature sensor is the target temperature of the wafer.

7. The control method according to claim 1, characterized in that, The control method further includes: When the object of temperature measurement represents a wafer carrier, the wafer is heated according to the initial heating power in the temperature control parameters, and the actual temperature of the temperature sensor during the heating process is obtained. The object to be measured during the heating process is determined based on the actual temperature and the temperature increment threshold of the temperature sensor.

8. An electronic device, characterized in that, include: One or more processors; A memory having stored one or more computer programs thereon, which, when executed by the one or more processors, cause the one or more processors to implement the control method according to any one of claims 1 to 7.

9. A computer-readable medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the control method according to any one of claims 1 to 7.

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