A semiconductor cavity temperature control method, device and medium

Abstract

The application provides a semiconductor cavity temperature control method and device and a computer readable medium, and relates to the technical field of semiconductors. In the production stage, only one temperature sensor is installed in the semiconductor cavity to detect the temperature of the outer circle of a wafer. The power of the outer circle power regulator is controlled by an outer circle PID adjustment. The output power of the inner circle power regulator is controlled according to the corresponding relationship between the temperature change and the output power of the inner and outer circle power regulators established in the pre-production calibration stage. Therefore, the wafer inner and outer circle temperature is more accurately controlled at low cost, and the heating uniformity is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor processing, in particular to a semiconductor cavity temperature control method and device, and a computer readable medium. BACKGROUND

[0002] In a semiconductor processing process, a Degas cavity is used to remove water vapor and other volatile impurities on the surface of a wafer to provide a clean wafer surface for subsequent processes. The Degas cavity is usually a vacuum chamber, and a heater is used to heat the wafer so that the water vapor and other impurities on the surface of the wafer are removed. The efficient decontamination function of the Degas cavity is an effective means to improve production accuracy and reliability.

[0003] During the heating of the wafer, the uniformity of the temperature distribution in the Degas cavity directly affects the process effect. In the prior art, a single power control component (such as a fuzzy controller) is used to control the power of the heating component, and a scheme (open-loop control scheme in production environment) of heating the entire Degas cavity by time and power segmentation; or a single temperature sensor (such as a thermocouple, a thermistor, etc.) is used to detect the temperature, and a PID controller (Proportional Integral Derivative Controller) is used to control and adjust the power of the heating component (single closed-loop scheme in production environment). Due to the non-uniformity of the temperature distribution in the Degas cavity, it is difficult to achieve accurate control of the uniform distribution of the temperature of the inner and outer circles of the wafer, thereby affecting the quality of the subsequent wafer process. SUMMARY

[0004] The present application aims to solve one of the problems in the related art to some extent. To this end, the present application provides a semiconductor cavity temperature control method and device, and a computer readable medium, which has the advantages of low cost, improved heating control precision and uniformity.

[0005] In order to achieve the above-mentioned purpose, as a first aspect of the present application, a semiconductor cavity temperature control method is provided, wherein the method comprises:

[0006] In the production phase after the cavity is put into production, the temperature of the region corresponding to the outer circle heater of the wafer is detected by the outer circle temperature sensor installed in the cavity, the difference between the detected temperature and the target temperature is used to control the output power of the outer circle power regulator to the outer circle heater by the outer circle proportional integral derivative (PID) controller, and the corresponding relationship between the output power of the inner and outer circle power regulators and the temperature change established in the test calibration phase is used to control the power output to the inner circle heater by the inner circle power regulator.

[0007] Optionally, the correspondence includes the correspondence between temperature, inner ring power regulator output power, and outer ring power regulator output power. The temperature in the correspondence is obtained by detecting the temperature of the corresponding area of ​​the inner and outer ring heaters of the wafer through independent inner and outer ring temperature sensors installed in the cavity. The output power of the inner and outer ring power regulators in the correspondence comes from the control of independent inner and outer ring PID controllers. The inner and outer ring PID controllers independently control the output power of the inner and outer ring power regulators based on the difference between the temperature detected by the inner and outer ring temperature sensors and the target temperature.

[0008] Optionally, during the testing and calibration phase, a thermocouple wafer (TC Wafer) is used to calibrate the relationship between the inner and outer ring temperature sensors and the established output power of the inner and outer ring power regulators as a function of temperature.

[0009] Optionally, the temperature detected by the temperature sensor is read at a preset cycle and the average temperature is calculated;

[0010] The PID controller controls the output power of the power regulator based on the difference between the average temperature detected by the temperature sensor and the target temperature.

[0011] Optionally, a programmable logic controller (PLC) can be used to automate the temperature control process during the testing and calibration phase and the production phase.

[0012] As a second aspect of the present invention, a semiconductor cavity temperature control device is provided, wherein the device is applied to temperature control of a semiconductor cavity during the production stage, the device comprising:

[0013] The inner ring heater is electrically connected to the inner ring power regulator and is used to heat the inner ring of the wafer under the control of the inner ring power regulator.

[0014] The outer ring heater is electrically connected to the outer ring power regulator and is used to heat the outer ring of the wafer under the control of the outer ring power regulator.

[0015] The outer ring temperature sensor is connected to the signal of the outer ring PID controller and is used to detect the temperature of the corresponding area of ​​the outer ring heater of the wafer and transmit the detected temperature to the outer ring PID controller.

[0016] The outer ring PID controller is connected to the outer ring temperature sensor and the outer ring power regulator signal respectively. It is used to control the output power of the outer ring power regulator based on the difference between the temperature of the corresponding area of ​​the outer ring heater detected by the outer ring temperature sensor and the target temperature.

[0017] The outer ring power regulator is used to output power to the outer ring heater under the control of the outer ring PID controller;

[0018] The inner ring power regulator is configured to output power to the inner ring heater according to a correspondence between the output power of the inner and outer ring power regulators and temperature changes established in the test calibration phase.

[0019] Optionally, the semiconductor cavity assembly structure in the production phase is different from the semiconductor cavity assembly structure in the test calibration phase.

[0020] The semiconductor cavity assembly structure in the test calibration phase further comprises:

[0021] The inner ring temperature sensor is connected to the inner ring PID controller and configured to detect the temperature of the corresponding area of the inner ring heater and transmit the detected temperature to the inner ring PID controller.

[0022] The inner ring PID controller is connected to the inner ring temperature sensor and the inner ring power regulator and configured to control the output power of the inner ring power regulator according to the difference between the temperature of the corresponding area of the inner ring heater detected by the inner ring temperature sensor and the target temperature.

[0023] The inner ring power regulator in the test calibration phase is configured to output power to the inner ring heater under the control of the inner ring PID controller.

[0024] The semiconductor cavity assembly structure in the test calibration phase further comprises:

[0025] The relationship building module is configured to read the temperature detected by the inner and outer ring temperature sensors and calculate the average temperature at a preset period, record the average temperature of the corresponding area of the inner and outer ring heaters and the output power of the inner and outer ring power regulators, and establish the correspondence between the output power of the inner and outer ring power regulators and temperature changes.

[0026] Optionally, an isolation part is arranged below the inner ring heater and the outer ring heater, and the inner ring temperature sensor and the outer ring temperature sensor are arranged on the isolation part, respectively, for detecting the temperature of the corresponding area of the inner ring heater and the outer ring heater.

[0027] Optionally, the semiconductor cavity further comprises:

[0028] The first, second and third side wall heaters are electrically connected to the side wall power regulator.

[0029] The side wall temperature sensor is configured to detect the side wall temperature.

[0030] The side wall power regulator is configured to output power to the first, second and third side wall heaters under the control of the side wall PID controller.

[0031] The sidewall PID controller controls the output power of the sidewall power regulator based on the difference between the temperature detected by the sidewall temperature sensor and the target temperature.

[0032] As a third aspect of the invention, a computer-readable medium is provided having a computer program stored thereon, which, when executed by a program execution unit, implements the method described in the first aspect of the invention.

[0033] This invention installs only one temperature sensor in the semiconductor cavity during the production stage to detect the temperature of the outer ring of the wafer. The power of the outer ring power regulator is controlled by an outer ring PID regulator, and the power of the inner ring power regulator is controlled according to the corresponding relationship between the output power of the inner and outer ring power regulators and temperature changes established during the pre-production calibration stage. This allows for more precise control of the temperature of the inner and outer rings of the wafer at low cost, thereby improving heating uniformity.

[0034] 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

[0035] Figure 1 This is a schematic flowchart of a semiconductor cavity temperature control method according to an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of the steps in the testing and calibration phase of one embodiment of the present invention;

[0037] Figure 3 This is a schematic diagram of the layout of the TC Wafer and embedded temperature sensor used during calibration in one embodiment of the present invention;

[0038] Figure 4 This is a schematic diagram of the production stage steps in one embodiment of the present invention;

[0039] Figure 5 This is a side view of the internal component structure of a semiconductor cavity in one embodiment of the present invention;

[0040] Figure 6 This is a top view of a heating lamp plate inside a semiconductor cavity according to an embodiment of the present invention;

[0041] Figure 7 This is a schematic diagram of the system structure for production verification of a semiconductor cavity control method in one embodiment of the present invention. Detailed Implementation

[0042] 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.

[0043] 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.

[0044] The technical solution provided by the present invention will be described in detail below with reference to specific embodiments.

[0045] To address the challenges of precisely controlling the wafer's inner and outer ring temperatures and preventing temperature inhomogeneity, solutions using a single power control component to regulate the heating element or a single temperature sensor with a single PID controller to adjust the heating element's power in semiconductor cavity temperature control often suffer from limitations. One possible solution is to employ multiple temperature sensors to separately detect the inner and outer ring temperatures in the production environment, and then use multiple independent controllers (such as PID controllers or fuzzy controllers) to adjust the heating power of the inner and outer rings. However, this approach still has several drawbacks. For example, limited space within the cavity makes it difficult to install too many temperature sensors, especially inner ring temperature sensors; independent detection and control of the inner and outer ring power regulators can lead to mutual interference, increasing the coupling and complexity of inner and outer ring temperature control; fuzzy controllers cannot improve control accuracy and stability; and using too many temperature sensors increases the overall system complexity and cost.

[0046] To address the technical challenges of precisely controlling wafer temperature and temperature distribution uniformity within semiconductor cavities (such as Degas cavities) in production environments, this invention proposes a semiconductor cavity temperature control method. This method comprises two stages: the first stage is a testing and calibration phase before the cavity is put into production, primarily used to establish the correlation between the output power of the inner and outer ring power regulators and temperature changes; the second stage is the production phase after the cavity is put into production, where the correlation between the output power of the inner and outer ring power regulators and temperature changes established during the testing and calibration phase is used to directly control the power output of the inner ring power regulator, thereby eliminating the need for an inner ring temperature sensor and an inner ring PID controller during the production phase.

[0047] Figure 1 This is a schematic flowchart of a semiconductor cavity temperature control method according to an embodiment of the present invention. The method includes:

[0048] Step S110: During the testing and calibration phase before the cavity is put into production, the temperature of the corresponding area of ​​the inner and outer ring heaters of the wafer is detected by the inner and outer ring temperature sensors installed independently in the cavity. The output power of the inner and outer ring power regulators is independently controlled by the independent inner and outer ring proportional integral derivative PID controllers according to the difference between the temperature detected by the inner and outer ring temperature sensors and the target temperature, and the corresponding relationship between the output power of the inner and outer ring power regulators and the temperature change is established.

[0049] During the testing and calibration phase before the wafer cavity is put into production, independent inner and outer ring temperature sensors are installed inside the cavity to detect the temperature of corresponding areas of the inner and outer ring heaters on the wafer. These sensors are connected to independent inner and outer ring PID controllers, feeding back the detected temperatures. The inner and outer ring PID controllers are then connected to inner and outer ring power regulators, providing power control signals. The inner and outer ring power regulators are electrically connected to the inner and outer ring heaters, outputting corresponding power to the heaters based on the power control signals from the inner and outer ring PID controllers, thus heating the heaters.

[0050] The semiconductor cavity described in this invention refers to a cavity used in the semiconductor wafer fabrication and chip manufacturing process that requires uniform heating of the inner and outer rings of the wafer. This includes, but is not limited to, Degas cavities, chemical vapor deposition (CVD) cavities, annealing cavities, photolithography cavities, bonding cavities, and physical vapor deposition (PVD) cavities.

[0051] The inner and outer ring heaters (collectively referred to as inner and outer ring heaters) are used to heat the inner and outer rings of the wafer under the control of the inner and outer ring power regulators. The inner and outer ring heaters are located at the bottom of the cavity, with the inner ring heater located inside the outer ring heater.

[0052] The inner and outer ring power regulators (referred to as inner and outer ring power regulators) are used to adjust the power output to the inner and outer ring heaters under the signal control of the PID controller.

[0053] The inner and outer ring temperature sensors (hereinafter referred to as inner and outer ring temperature sensors) are used to independently detect the temperature of corresponding areas of the inner and outer ring heaters on the wafer, and transmit the detected temperature signals to the corresponding inner and outer ring PID controllers respectively. This invention does not specifically limit the type of temperature sensor, such as thermocouples, resistance temperature detectors (RTDs), thermistors, infrared sensors, etc.

[0054] The inner and outer PID controllers (referred to as inner and outer PID controllers) are used to control the output power of the inner and outer power regulators respectively based on the temperature difference between the corresponding area of ​​the inner and outer heaters detected by the inner and outer temperature sensors and the target temperature, so that the temperature of the corresponding area of ​​the inner and outer heaters gradually increases until the target temperature is reached.

[0055] The power regulator is the execution unit, responsible for directly adjusting the power of the inner and outer wafer heaters; the PID controller is the decision-making unit, responsible for calculating the optimal control strategy based on feedback errors. The combination of the temperature sensor, PID controller, and power regulator forms a closed-loop temperature control system, ensuring rapid response and high-precision stability of the cavity temperature.

[0056] Users can set the target temperature of the wafer surface through the human-machine interface. The inner ring PID controller compares the temperature of the corresponding area of ​​the inner ring heater detected by the inner ring temperature sensor with the target temperature. It calculates the required control quantity using a PID algorithm and then outputs a control signal to the inner ring power regulator. The inner ring power regulator receives the control signal from the inner ring PID controller and converts it into the power output of the inner ring heater (such as adjusting voltage or on / off time), thereby raising or lowering the heater's temperature. For example, if the actual detected temperature is lower than the target temperature, the control quantity output by the PID controller increases, and the power regulator increases its output power, thus raising the temperature. If the actual detected temperature is higher than the target temperature, the control quantity output by the PID controller decreases, and the power regulator decreases its output power, thus achieving a cooling effect. Similarly, the outer ring temperature control principle is the same and will not be elaborated further.

[0057] Step S120: In the production stage after the cavity is put into production, the temperature of the corresponding area of ​​the outer ring heater of the wafer is detected by the outer ring temperature sensor installed in the cavity. The outer ring PID controller controls the output power of the outer ring power regulator to the outer ring heater according to the difference between the detected temperature and the target temperature. At the same time, according to the corresponding relationship between the output power of the inner and outer ring power regulators and the temperature change established in the test and calibration stage, the power output of the inner ring power regulator to the inner ring heater is controlled.

[0058] The cavity component structure differs between the production stage and the testing and calibration stage in this invention. During the production stage, an inner ring power regulator, an outer ring power regulator, an outer ring PID controller, and an outer ring temperature sensor need to be installed inside the cavity. However, an inner ring temperature sensor and an inner ring PID controller are not required. The power control of the inner ring power regulator is directly controlled based on the corresponding relationship between the output power of the inner and outer ring power regulators and temperature changes established during the testing and calibration stage.

[0059] The relationship between the output power of the inner and outer ring power regulators and temperature, established during the testing and calibration phase, includes the correlation between temperature, the output power of the inner ring power regulator, and the output power of the outer ring power regulator. The temperature in this correlation is obtained by detecting the temperature of the corresponding areas of the inner and outer ring heaters on the wafer using independently installed inner and outer ring temperature sensors within the testing and calibration chamber. The output power of the inner and outer ring power regulators in this correlation is controlled by independent inner and outer ring PID controllers within the testing and calibration chamber. Specifically, the inner and outer ring PID controllers installed within the testing and calibration chamber independently control the output power of the inner and outer ring power regulators based on the difference between the temperature detected by the inner and outer ring temperature sensors and the target temperature.

[0060] By comparing the component structure and temperature control methods within the cavity during the testing and calibration phase and the actual production phase, it can be found that the solution provided by this invention only requires one outer ring temperature sensor and one outer ring PID controller during the actual production phase, eliminating the need for an inner ring temperature sensor and an inner ring PID controller. The temperature control method changes from independent control of the inner and outer rings to coordinated control by the inner ring power regulator based on the established correspondence. The solution provided by this invention can achieve precise control of the inner and outer ring temperatures and make the temperature distribution on the wafer surface more uniform, while also reducing system complexity and equipment costs.

[0061] Figure 2 This is a schematic flowchart of the testing and calibration phase in one embodiment of the present invention. In this embodiment, the control program can be written into a programmable logic controller (PLC) by an industrial control computer. The PLC enables automated control of each component during the testing and calibration phase, automatically establishing and calibrating the relationship between the output power of the inner and outer coil power regulators and temperature changes according to a preset process.

[0062] During the testing and calibration phase, thermocouple wafers (TC wafers) can be used to calibrate the accuracy of the temperature measurement, temperature uniformity, and output power of the temperature sensor. TC wafers are wafers with embedded high-precision temperature sensors, used for real-time measurement of wafer surface temperature and evaluation of wafer surface temperature uniformity. They provide temperature data support for calibration, ensuring the accuracy and reliability of the temperature detected by the temperature sensor and the output power of the inner and outer coil power regulators as much as possible.

[0063] Figure 3This is a schematic diagram of the layout of the TC Wafer and embedded temperature sensors used during calibration in one embodiment of the present invention. Each black solid dot in the figure represents a temperature sensor embedded on the wafer surface. A total of 17 temperature sensors (e.g., thermocouples) are evenly arranged in a staggered manner from the center point to the outermost layer. The temperature sensors embedded on the TC Wafer wafer surface can measure the temperature at multiple locations on the wafer surface in real time, thereby obtaining the temperature distribution of the entire wafer. In addition, it can also capture dynamic temperature changes such as heating, cooling, isothermal processes, and delay time.

[0064] The following is a detailed description of the process during the testing and calibration phase:

[0065] Step 201: Perform initialization operations;

[0066] The initialization includes the initialization of various components within the cavity, such as the initialization of the calibration array, and the initialization of the parameters and states of components such as the PID controller, power regulator, temperature sensor, and heater.

[0067] The calibration array is used to record the target temperature after calibration, and is used to determine whether the corresponding target temperature has been calibrated.

[0068] Step 202: Run the control program and start heating;

[0069] After the initialization operation is completed, the control program in the PLC is run. Under the control of the control program, the inner and outer ring power regulators are turned on at the same time, and the output power of the inner and outer ring power regulators is controlled by the PID controller. The inner and outer ring heaters start to heat up, so that the temperature of the corresponding areas of the inner and outer ring heaters gradually increases.

[0070] Step 203: Determine if the target temperature is in the calibration array. If not, proceed to step 204; if it is, proceed to step 205.

[0071] Step 204: If the target temperature is not in the calibration array, add the target temperature to the calibration array, and then execute step 203.

[0072] Step 205: If the target temperature is already in the calibration array, determine whether the target temperature has been calibrated. If it has been calibrated, proceed to step 206; if it has not been calibrated, proceed to step 207.

[0073] Whether calibration is complete can be recorded by marking a completion flag in the data cell structure of the calibration array.

[0074] Step 206: Determine if recalibration is needed. If so, change the target temperature calibration completion status to incomplete status and then proceed to step 205; otherwise, proceed to step 210.

[0075] In some cases, recalibration of the target temperature may be necessary, such as when replacing hardware devices like temperature sensors or power regulators. Target temperatures requiring recalibration can be identified by setting a recalibration flag.

[0076] Step 207: Determine if the current average temperature is less than the target temperature. If it is less, proceed to step 208; if it is not less, it means the target temperature has been reached, and the calibration can be ended. Proceed to step 210.

[0077] Step 208: Read the temperature according to the preset cycle and calculate the average temperature;

[0078] This step reads the current inner and outer ring temperature values ​​of the wafer surface in real time from independently installed inner and outer ring temperature sensors (first temperature sensor and second temperature sensor), calculates the average temperature, and obtains the first average value.

[0079] During this process, the temperature values ​​of multiple temperature sensors on the surface of the TC Wafer can be read in real time. The average value of the multiple temperature values ​​is then calculated to obtain the calibration average value. The difference between the calibration average value and the first average value can be used to adjust the parameters of the PID controller through the control program, thereby adjusting the output power of the inner and outer ring power regulators to calibrate the correspondence between the power regulator output power and the average temperature.

[0080] The preset period for reading the temperature value measured by the temperature sensor in this step can be set by configuration parameters, such as 100ms, 300ms, etc., depending on the physical characteristics of the device and application requirements.

[0081] Step 209: After saving the average output power and temperature of the internal and external power regulators, return to step 207.

[0082] This step records the average temperature of the corresponding areas of the inner and outer ring heaters and the output power of the inner and outer ring power regulators, thereby establishing the relationship between the output power of the inner and outer ring power regulators and temperature changes.

[0083] Step 210: When the average temperature is not less than the target temperature, end the heating process.

[0084] When the current average temperature is greater than or equal to the target temperature, wafer heating can be stopped, and the calibration process for the target temperature can be stopped after the calibration target is completed.

[0085] Figure 4This is a schematic diagram of the production stage steps in one embodiment of the present invention. During the production stage, a programmable logic controller (PLC) can automatically control each component within the cavity, reducing the potential impact of manual intervention and thus improving the stability and reliability of the entire system. In the production stage, only one temperature sensor is needed to detect the temperature of the outer wafer, transmitting the temperature signal to the outer PID controller. The outer PID controller adjusts the power of the outer power regulator, while the power of the inner power regulator is controlled based on the correspondence between the output power of the inner and outer power regulators obtained during the testing and calibration stage. This simplifies the system structure and reduces costs.

[0086] Step 401: Read the corresponding data of the output power of the calibrated inner and outer ring power regulators as a function of temperature;

[0087] After the system is powered on and initialized, the control program is loaded and run. The control program reads the data on the relationship between the output power of the inner and outer coil power regulators and temperature changes, which was established and calibrated during the test and calibration phase, from the storage medium.

[0088] Step 402: Start heating;

[0089] Under the control of the control program, the inner and outer ring power regulators are turned on simultaneously, and the inner and outer ring heaters begin to heat up, causing the temperature of the corresponding areas of the inner and outer ring heaters to gradually increase.

[0090] Step 403: Determine if the average temperature is within the error range of the target temperature. If it is within the error range of the target temperature, proceed to step 406 to end heating; if it is not within the target temperature range, proceed to step 404.

[0091] In production mode, before each wafer is placed into the cavity and heating begins, the average temperature is set to a value lower than the target temperature. After heating begins, the system continuously reads the temperature from the temperature sensor at preset intervals and calculates the average value, and continuously checks whether the average temperature is within the error range of the target temperature.

[0092] Step 404: Read the temperature according to the preset cycle and calculate the average value;

[0093] In this step, the system will continuously read the temperature detected by one or more outer ring temperature sensors at a preset cycle (e.g., 100ms) and calculate the average value of multiple temperature detection values; it can also calculate the temperature detected by a temperature sensor multiple times within a preset statistical window (e.g., 500ms) and calculate the average temperature within the preset statistical window.

[0094] Step 405: The outer ring power regulator is controlled by the outer ring PID controller for heating, and the inner ring power regulator controls the output power according to the corresponding relationship. Then, step 403 is executed.

[0095] In this step, the outer ring PID controller controls the output power of the outer ring power regulator based on the average temperature, while the output power of the inner ring power regulator is controlled based on the corresponding relationship between the output power of the inner and outer ring power regulators and temperature changes established during the test and calibration phase.

[0096] After calculating the current average temperature, the average temperature is transmitted to the outer ring PID controller. The outer ring PID controller controls the output power of the outer ring power regulator to the outer ring heater based on the difference between the average temperature and the target temperature. At the same time, the system reads the output power of the inner ring power regulator corresponding to the output power of the outer ring power regulator at the current temperature based on the corresponding relationship between the output power of the inner and outer ring power regulators and the temperature obtained in step 401, and transmits the read output power information of the inner ring power regulator to the inner ring power regulator, thereby controlling the output power of the inner ring power regulator.

[0097] Step 406: End heating if the average temperature is not lower than the target temperature.

[0098] This invention innovatively separates the power control methods in the testing and calibration stage from those in the production stage. In the testing and calibration stage, the correspondence between the output power of the inner and outer ring power regulators is obtained. Based on this correspondence, power control and automated control logic based on a single PID controller using an outer ring temperature sensor are implemented in the production stage. This solves the problems of uneven temperature distribution, system complexity, and high cost in traditional semiconductor manufacturing cavity heating systems.

[0099] Figure 5 This is a side view of the internal component structure of a semiconductor cavity according to an embodiment of the present invention. In this embodiment, a heating lamp disk for mounting an inner ring heater and an outer ring heater is provided above the wafer. The heaters in this embodiment are halogen heating lamps. An outer ring temperature sensor is provided above or below the edge of the wafer surface. The temperature sensor can be implemented using a thermocouple.

[0100] Figure 6 This is a top view of a heating lamp disk inside a semiconductor cavity according to an embodiment of the present invention. The lamp disk is divided into an inner ring and an outer ring. Multiple inner ring heaters of the inner ring are electrically connected to an inner ring power regulator located outside the cavity through the lamp disk. Multiple outer ring heaters of the outer ring are electrically connected to an outer ring power regulator located outside the cavity through the lamp disk.

[0101] In another embodiment of the present invention, an isolation section is provided below the inner ring heater and the outer ring heater respectively. An inner ring temperature sensor (first thermocouple) and an outer ring temperature sensor (second thermocouple) are provided on the isolation section, which are used to detect the temperature of the corresponding areas of the inner ring heater and the outer ring heater respectively. The purpose of providing the isolation section is to isolate the influence of the upper inner and outer ring heaters on the temperature sensors.

[0102] In another embodiment of the present invention, the inner ring heater and the outer ring heater are electrically connected to a one-to-one matched inner ring DC power supply and an outer ring DC power supply, respectively, or the inner ring heater and the outer ring heater are electrically connected to an inner ring power regulator and an outer ring power regulator, respectively.

[0103] In one embodiment of the present invention, a first sidewall heater, a second sidewall heater, and a third sidewall heater are further provided on the sidewall of the semiconductor cavity for heating the sidewall region of the cavity; the first sidewall heater, the second sidewall heater, and the third sidewall heater are electrically connected to the sidewall power regulator respectively;

[0104] The sidewall power regulator is used to output power to the first sidewall heater, the second sidewall heater and the third sidewall heater under the control of the sidewall PID controller;

[0105] The sidewall PID controller controls the output power of the sidewall power regulator based on the difference between the sidewall temperature detected by the sidewall temperature sensor (which can be the average of three sidewall temperatures) and the target temperature.

[0106] Adding sidewall heaters can increase the heating rate of the cavity and also prevent uneven wafer surface temperature caused by uneven cavity sidewall temperature.

[0107] The technical solution and effects of the present invention will be described below with reference to experimental data.

[0108] In one embodiment of the present invention, a TC Wafer is used for calibration during the testing and calibration phase. To accurately obtain the corresponding relationship between the outputs of the inner and outer ring power regulators, a control strategy using independent PID controllers for the inner and outer rings is adopted. The target temperature is set to 120℃, and the PID controller parameters are determined after repeated debugging and optimization: inner ring proportional coefficient Kp1=0.4, integral coefficient Ki1=0.06, derivative coefficient Kd1=0.08; outer ring proportional coefficient Kp2=0.35, integral coefficient Ki2=0.05, derivative coefficient Kd2=0.1.

[0109] During the testing and calibration process, data was collected in 3°C increments, with the inner and outer ring temperatures, regulator output power, and corresponding average temperatures read every 100ms. By continuously heating and recording data in real time, a correlation was established between temperature, inner ring regulator output power, and outer ring regulator output power. The data was finally compiled into Table 1 below. Table 1 shows the correlation between the inner and outer ring regulator output power and temperature changes, where the regulator output power can be represented as a percentage of the total output power.

[0110] Table 1

[0111]

[0112] To verify the validity of the data obtained during the testing and calibration phase, this invention also verified the cavity temperature control effect before putting the cavity into actual production, based on the correspondence between the output power of the inner and outer ring power regulators obtained during the testing and calibration phase. During verification, the outer ring PID controller dynamically adjusted the output power of the outer ring power regulator according to the real-time temperature detected by the outer ring temperature sensor, while the inner ring power regulator directly called upon the output power based on the calibrated correspondence. During the experiment, temperature data of the inner and outer rings were continuously collected at a preset interval of 100ms, resulting in the temperature changes shown in Table 2 below:

[0113] Table 2

[0114]

[0115] As can be clearly seen from the temperature change data in Table 2, the inner and outer ring temperatures rise rapidly and gradually approach the target temperature of 120℃ as the heating time progresses. Once the temperature approaches the target value, the PID control of the outer ring power regulator and the power output of the inner ring based on the calibrated correspondence between the output power of the inner and outer ring power regulators work together to keep the inner and outer ring temperatures stable near the target temperature, with fluctuations controlled within ±1.5℃.

[0116] A detailed analysis was conducted on the temperature data collected during the production verification process, and the mean and standard deviation of the temperature error were calculated. The results showed that the mean temperature of the inner ring was 119.8℃, with a standard deviation of 0.8℃; the mean temperature of the outer ring was 120.2℃, with a standard deviation of 0.9℃. The average errors between the inner and outer ring temperatures and the target temperature of 120℃ were 0.2℃ and 0.2℃ respectively, both with error rates below 0.2%, far less than the industry standard of ±3℃ for similar equipment.

[0117] In summary, the output correspondence between the inner and outer ring power regulators established through calibration experiments, combined with the control strategy in the production verification stage, enables the TC Wafer to accurately reach the target temperature of 120℃ during the heating process. Moreover, the temperature control is stable and the error is minimal, which fully demonstrates that the solution is accurate and feasible in practical applications, has good reliability and practicality, and can be effectively applied to relevant production and manufacturing scenarios.

[0118] Figure 7This is a schematic diagram of a system structure for production verification of a semiconductor cavity control method according to an embodiment of the present invention. The program for implementing the semiconductor cavity temperature control method provided by the present invention can be loaded and run in a programmable logic controller (PLC) in the form of hardware and software modules. The PLC is equivalent to a device or equipment for implementing the method provided by the present invention. This device or equipment can be controlled by an industrial control computer. The function of the PID controller can also be integrated into the PLC in the form of a module. In this embodiment, the inner and outer ring heaters use halogen heating lamps, and the outer ring temperature sensor is implemented using a K-type thermocouple.

[0119] 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).

[0120] 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 the temperature of a semiconductor cavity, characterized in that, The semiconductor cavity temperature control method includes: During the production phase after the wafer cavity is put into production, the temperature of the corresponding area of ​​the outer ring heater is detected by the outer ring temperature sensor installed inside the cavity. The PID controller controls the output power of the outer ring power regulator to the outer ring heater based on the difference between the detected temperature and the target temperature. At the same time, based on the correspondence between the output power of the inner and outer ring power regulators and temperature changes established during the testing and calibration phase, the power output of the inner ring power regulator to the inner ring heater is controlled. The target temperature is set by the user through the human-machine interface. The temperature during the testing and calibration phase is the target temperature of the entire wafer surface. The correspondence includes the relationship between temperature, inner ring power regulator output power, and outer ring power regulator output power. The temperature in this correspondence is obtained by detecting the temperature of corresponding areas of the inner and outer ring heaters on the wafer using independently installed inner and outer ring temperature sensors within the cavity. The output power of the inner and outer ring power regulators in this correspondence is controlled by independent inner and outer ring PID controllers. These PID controllers independently control the output power of the inner and outer ring power regulators based on the difference between the temperatures detected by the inner and outer ring temperature sensors and the target temperature. During the testing and calibration phase, a thermocouple wafer is used to calibrate the correspondence between the inner and outer ring temperature sensors and the established relationship between the output power of the inner and outer ring power regulators and temperature changes. The testing and calibration phase also includes calibration of the target temperature. This calibration involves calculating the average temperature values ​​obtained by multiple temperature sensors embedded on the TCWafer wafer surface to obtain a calibrated average value. If the calibrated average value reaches the target temperature, this calibrated average value is taken as the target temperature for the testing and calibration phase. The multiple temperature sensors are evenly and staggered from the center point of the wafer to the outermost layer. The difference is the difference between the average value of the inner and outer ring temperature sensors and the calibrated average value.

2. The semiconductor cavity temperature control method according to claim 1, characterized in that, The temperature detected by the temperature sensor is read and the average temperature is calculated according to a preset cycle; The PID controller controls the output power of the power regulator based on the difference between the average temperature detected by the temperature sensor and the target temperature.

3. The semiconductor cavity temperature control method according to claim 1 or 2, characterized in that, Programmable logic controllers are used to automate the temperature control process during the testing and calibration phases and the production phases.

4. A semiconductor cavity temperature control device, wherein the semiconductor cavity temperature control device is applied to the temperature control of a semiconductor cavity during the production stage, characterized in that, The semiconductor cavity temperature control device includes: The inner ring heater is electrically connected to the inner ring power regulator and is used to heat the inner ring of the wafer under the control of the inner ring power regulator. The outer ring heater is electrically connected to the outer ring power regulator and is used to heat the outer ring of the wafer under the control of the outer ring power regulator. The outer ring temperature sensor is connected to the signal of the outer ring PID controller and is used to detect the temperature of the corresponding area of ​​the outer ring heater of the wafer and transmit the detected temperature to the outer ring PID controller. The outer ring PID controller is connected to the outer ring temperature sensor and the outer ring power regulator signal respectively. It is used to control the output power of the outer ring power regulator based on the difference between the temperature of the corresponding area of ​​the outer ring heater detected by the outer ring temperature sensor and the target temperature. The outer ring power regulator is used to output power to the outer ring heater under the control of the outer ring PID controller; The inner ring power regulator is used to output power to the inner ring heater based on the relationship between the output power of the inner and outer ring power regulators and temperature changes established during the testing and calibration phase. The semiconductor cavity assembly structure in the production stage is different from that in the testing and calibration stage. The semiconductor cavity assembly structure in the test and calibration phase also includes: The inner ring temperature sensor is connected to the signal of the inner ring PID controller and is used to detect the temperature of the corresponding area of ​​the inner ring heater of the wafer and transmit the detected temperature to the inner ring PID controller. The inner ring PID controller is connected to the inner ring temperature sensor and the inner ring power regulator signal respectively. It is used to control the output power of the inner ring power regulator based on the difference between the temperature of the corresponding area of ​​the inner ring heater detected by the inner ring temperature sensor and the target temperature. The inner ring power regulator in the test and calibration phase is used to output power to the inner ring heater under the control of the inner ring PID controller. The semiconductor cavity assembly structure in the test and calibration phase also includes: The relationship construction module is used to read the temperature detected by the inner and outer ring temperature sensors at a preset cycle and calculate the average temperature, record the average temperature of the corresponding area of ​​the inner and outer ring heaters and the output power of the inner and outer ring power regulators, thereby establishing the corresponding relationship between the output power of the inner and outer ring power regulators and the temperature change.

5. The semiconductor cavity temperature control device according to claim 4, characterized in that, An isolation section is provided below the inner ring heater and the outer ring heater, and the inner ring temperature sensor and the outer ring temperature sensor are respectively installed on the isolation section to detect the temperature of the corresponding area of ​​the inner ring heater and the outer ring heater.

6. The semiconductor cavity temperature control device according to claim 4 or 5, characterized in that, The semiconductor cavity also includes: The first sidewall heater, the second sidewall heater, and the third sidewall heater are used to heat the sidewall area of ​​the cavity; the first sidewall heater, the second sidewall heater, and the third sidewall heater are electrically connected to the sidewall power regulator respectively; Sidewall temperature sensor, used to detect sidewall temperature; The sidewall power regulator is used to output power to the first sidewall heater, the second sidewall heater and the third sidewall heater under the control of the sidewall PID controller; The sidewall PID controller controls the output power of the sidewall power regulator based on the difference between the temperature detected by the sidewall temperature sensor and the target temperature.

7. A computer-readable medium having a computer program stored thereon, characterized in that, When the computer program is executed by the program execution unit, it implements the semiconductor cavity temperature control method according to any one of claims 1 to 3.

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