Semiconductor cavity temperature control method and device, and medium

Abstract

The invention provides a semiconductor cavity temperature control method, a semiconductor cavity temperature control device and a computer readable medium, and relates to the technical field of semiconductors. Only one temperature sensor is installed in a semiconductor cavity in the production stage to detect the temperature of a wafer outer ring, and the power of an outer ring power regulator is regulated and controlled through an outer ring PID; the power of the inner-ring power regulator is controlled to be output according to the corresponding relation of the output power of the inner-ring power regulator and the output power of the outer-ring power regulator along with temperature change established in the calibration stage before production, so that the temperatures of the inner ring and the outer ring of the wafer are 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: In the production phase after the cavity is put into production, the temperature of the corresponding region of the outer circle heater of the wafer is detected by the outer circle temperature sensor installed in the cavity, the output power of the outer circle power regulator to the outer circle heater is controlled by the outer circle proportional integral derivative (PID) controller according to the difference between the detected temperature and the target temperature, and the power output to the inner circle heater of the inner circle power regulator is controlled according to 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.

[0006] Optionally, the corresponding relationship comprises a corresponding relationship between temperature, inner ring power amplifier output power and outer ring power amplifier output power, the temperature in the corresponding relationship is obtained by detecting the temperature of the corresponding area of the wafer inner ring heater and the wafer outer ring heater by the independently installed inner and outer ring temperature sensors in the cavity, and the inner and outer ring power amplifier output power in the corresponding relationship respectively comes from the control of the mutually independent inner and outer ring PID controllers, the inner and outer ring PID controllers respectively independently control the output power of the inner and outer ring power amplifiers according to the difference between the temperature detected by the inner and outer ring temperature sensors and the target temperature.

[0007] Optionally, in the test calibration stage, a thermocouple wafer (TC Wafer) is used to calibrate the inner and outer ring temperature sensors and the corresponding relationship between the output power of the inner and outer ring power amplifiers and the temperature.

[0008] Optionally, the temperature detected by the temperature sensor is read and the average temperature is calculated at a preset period. The PID controller controls the output power of the power amplifier according to the difference between the average temperature detected by the temperature sensor and the target temperature.

[0009] Optionally, a programmable logic controller is used to automatically control the temperature control process in the test calibration stage and the production stage.

[0010] As a second aspect of the present application, a semiconductor cavity temperature control device is provided, wherein the device is applied to the temperature control of the semiconductor cavity in the production stage, and the device comprises: The inner ring heater is electrically connected with the inner ring power amplifier and is used to heat the inner ring of the wafer under the control of the inner ring power amplifier. The outer ring heater is electrically connected with the outer ring power amplifier and is used to heat the outer ring of the wafer under the control of the outer ring power amplifier. The outer ring temperature sensor is signal connected with the outer ring PID controller and is used to detect the temperature of the corresponding area of the wafer outer ring heater and transmit the detected temperature to the outer ring PID controller. The outer ring PID controller is signal connected with the outer ring temperature sensor and the outer ring power amplifier respectively and is used to control the output power of the outer ring power amplifier according to the difference between the temperature of the corresponding area of the wafer outer ring heater detected by the outer ring temperature sensor and the target temperature. The outer ring power amplifier is used to output power to the outer ring heater under the control of the outer ring PID controller. The inner ring power amplifier is used to output power to the inner ring heater according to the corresponding relationship between the output power of the inner and outer ring power amplifiers and the temperature established in the test calibration stage.

[0011] Optionally, the semiconductor cavity assembly structure in the production stage is different from the semiconductor cavity assembly structure in the test calibration stage. The semiconductor cavity assembly structure in the test calibration stage further comprises: The inner ring temperature sensor is connected with the inner ring PID controller in signal and is used for detecting the temperature of the corresponding area of the wafer inner ring heater and transmitting the detected temperature to the inner ring PID controller. The inner ring PID controller is connected with the inner ring temperature sensor and the inner ring power regulator in signal respectively and is used for controlling 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. The inner ring power regulator in the test calibration stage is used for outputting power to the inner ring heater under the control of the inner ring PID controller. The semiconductor cavity assembly structure in the test calibration stage further comprises: The relationship building module is used for reading the temperature detected by the inner and outer ring temperature sensors and calculating the average temperature, recording 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, so as to establish the corresponding relationship between the output power of the inner and outer ring power regulators and the temperature change.

[0012] Optionally, an isolation part is arranged below the inner ring heater and the outer ring heater respectively, and the inner ring temperature sensor and the outer ring temperature sensor are arranged on the isolation part respectively and are used for detecting the temperature of the corresponding area of the inner ring heater and the outer ring heater respectively.

[0013] Optionally, the semiconductor cavity further comprises: The first, second and third side wall heaters are used for heating the side wall area of the cavity, and the first, second and third side wall heaters are electrically connected to the side wall power regulator respectively. The side wall temperature sensor is used for detecting the side wall temperature. The side wall power regulator is used for outputting power to the first, second and third side wall heaters under the control of the side wall PID controller. The side wall PID controller controls the output power of the side wall power regulator according to the difference between the temperature detected by the side wall temperature sensor and the target temperature.

[0014] As a third aspect of the present application, a computer readable medium is provided, which stores a computer program, and the computer program is executed by a program execution unit to realize the method in the first aspect of the present application.

[0015] The present application only installs one temperature sensor to detect the wafer outer ring temperature in the production stage of the semiconductor cavity, controls the power of the outer ring power regulator through an outer ring PID adjustment, and controls the output of the inner ring power regulator according to the corresponding relationship between the output power of the inner and outer ring power regulators and the temperature established in the pre-production calibration stage, so as to realize more accurate control of the inner and outer ring temperatures of the wafer at low cost, and improve the heating uniformity.

[0016] The features and advantages of the present application will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings. The best mode or embodiment of the present application will be described in detail with reference to the drawings, but the present application is not limited thereto. In addition, the features, elements and components appearing in each of the following text and drawings are multiple, and different symbols or numbers are marked for the convenience of representation, but all represent the same or similar structures or function parts. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The semiconductor cavity temperature control method step flowchart provided by an embodiment of the present application is shown in the figure; Figure 2 The step flowchart of the test calibration stage in an embodiment of the present application is shown in the figure; Figure 3 The layout of the TC Wafer and embedded temperature sensor used in calibration in an embodiment of the present application is shown in the figure; Figure 4 The step flowchart of the production stage in an embodiment of the present application is shown in the figure; Figure 5 The side view of the internal component structure of the semiconductor cavity in an embodiment of the present application is shown in the figure; Figure 6 The top view of the heating lamp plate in the semiconductor cavity in an embodiment of the present application is shown in the figure; Figure 7 The system structure diagram for production verification of the semiconductor cavity control method in an embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0018] Embodiments of the present application will be described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. Based on the embodiments in the embodiments, it is intended to explain the present application, and cannot be understood as a limitation of the present application.

[0019] In this specification, "one embodiment" or "an example" or "an example" means that the specific features, structures or characteristics described in connection with the embodiment itself can be included in at least one embodiment of the present disclosure. The appearance of the phrase "in one embodiment" at various places in the specification does not necessarily mean the same embodiment.

[0020] The technical solutions provided by the application are described in detail below in combination with specific embodiments.

[0021] For the scheme of controlling the temperature of a semiconductor cavity by using a single power control component to control a heating component or using a single temperature sensor to cooperate with a single PID controller to adjust the power of the heating component, it is difficult to accurately control the temperature of the inner and outer circles of a wafer and the non-uniformity of the temperature, and a possible solution is to use multiple temperature sensors to detect the temperatures of the inner and outer circles of the wafer in a production environment, and use multiple controllers (for example, PID controllers, fuzzy controllers, etc.) that are independent of each other to adjust the heating power of the inner and outer circles of the wafer. However, this scheme still has many defects, for example, due to the limited space in the cavity, it is difficult to install too many temperature sensors, especially the temperature sensors for the inner circle; the independent detection and control of the power of the inner and outer circle power adjusters will cause mutual influence, thereby increasing the coupling and complexity of the temperature control of the inner and outer circles; when the fuzzy controller is used, the control accuracy and stability cannot be improved; in addition, too many temperature sensors will increase the complexity and cost of the entire system.

[0022] In order to accurately control the temperature of a wafer in a semiconductor cavity (for example, a Degas cavity) and the uniformity of the temperature distribution in the production environment, the application provides a semiconductor cavity temperature control method, which is divided into two stages. The first stage is a test calibration stage before the cavity is put into production, which is mainly used to establish the corresponding relationship between the output power of the inner and outer circle power adjusters and the temperature change; the second stage is a production stage after the cavity is put into production, which uses the corresponding relationship between the output power of the inner and outer circle power adjusters and the temperature change established in the test calibration stage to directly control the power output of the inner circle power adjuster, thereby saving the inner circle temperature sensor and the inner circle PID controller in the production stage.

[0023] Figure 1 The semiconductor cavity temperature control method provided by an embodiment of the application has the steps of: In step S110, in the test calibration stage before the cavity is put into production, the temperatures of the corresponding regions of the inner and outer circle heaters of the wafer are detected by the independently installed inner and outer circle temperature sensors in the cavity, the output powers of the inner and outer circle power adjusters are independently controlled by the independently installed inner and outer circle proportional integral differential (PID) controllers according to the differences between the detected temperatures and the target temperatures, and the corresponding relationship between the output powers of the inner and outer circle power adjusters and the temperature change is established. In the test calibration stage before the chamber goes into production, independent inner and outer ring temperature sensors for detecting the temperature of the corresponding area of the inner and outer ring heaters in the wafer are installed in the chamber, the inner and outer ring temperature sensors are respectively connected with independent inner and outer ring PID controllers, and the detected inner and outer ring temperatures are fed back to the inner and outer ring PID controllers. The inner and outer ring PID controllers are respectively connected with inner and outer ring power regulators to provide power control signals for the inner and outer ring power regulators. The inner and outer ring power regulators are respectively electrically connected with the inner and outer ring heaters, and the inner and outer ring power regulators output corresponding power to the inner and outer ring heaters according to the power control signals output by the inner and outer ring PID controllers, so that the heaters heat.

[0024] The semiconductor chamber in the present application refers to a chamber that needs to uniformly heat the inner and outer rings of a wafer during the process of manufacturing chips based on semiconductor wafers. It includes but is not limited to Degas chambers, chemical vapor deposition (CVD) chambers, annealing chambers, photolithography chambers, bonding chambers, physical vapor deposition (PVD) chambers, etc.

[0025] The inner and outer ring heaters (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 arranged at the bottom of the chamber, and the inner ring heater is located inside the outer ring heater.

[0026] 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.

[0027] The inner and outer ring temperature sensors (referred to as inner and outer ring temperature sensors) are used to independently detect the temperature of the corresponding area of the inner and outer ring heaters of the wafer, and transmit the detected temperature signals to the corresponding inner and outer ring PID controllers. The present application does not specifically limit the type of temperature sensor, which can be a thermocouple, a thermal resistor, a thermal sensor, an infrared sensor, etc.

[0028] The inner and outer ring PID controllers (referred to as inner and outer ring PID controllers) are used to respectively control the output power of the inner and outer ring power regulators according to the difference between the temperature of the corresponding area of the inner and outer ring heaters detected by the inner and outer ring temperature sensors and the target temperature, so that the temperature of the corresponding area of the inner and outer ring heaters gradually increases until the target temperature is reached.

[0029] Among them, the power regulator is an execution unit responsible for directly adjusting the power of the inner and outer ring heaters of the wafer; the PID controller is a decision unit responsible for calculating the optimal control strategy based on the feedback error. Through the combination of temperature sensors, PID controllers and power regulators, a closed-loop temperature control system is formed, which can ensure the rapid response and high-precision stability of the chamber temperature.

[0030] The user can set the target temperature of the wafer surface through the human-machine interface. The inner ring PID controller compares the temperature of the wafer inner ring heater corresponding area detected by the inner ring temperature sensor with the error of the target temperature, calculates the required control amount through the PID algorithm, and then outputs the control signal to the inner ring power regulator. After receiving the control signal of the inner ring PID controller, the inner ring power regulator converts the control signal into the power output (such as adjusting the voltage or on-off time) of the inner ring heater, so as to heat or cool the heater. For example, if the actual detected temperature is lower than the target temperature value, the control amount output by the PID controller increases, the output power of the power regulator increases, and the heater is heated and warmed up. If the actual detected temperature is higher than the target temperature value, the control amount output by the PID controller decreases, the output power of the power regulator decreases, and the cooling effect is realized. Similarly, the outer ring temperature regulation principle is the same, and will not be described here.

[0031] In step S120, in the production stage after the cavity is put into production, the temperature of the wafer outer ring heater corresponding area is detected by the outer ring temperature sensor installed in the cavity, and the output power of the outer ring power regulator to the outer ring heater is controlled by the outer ring PID controller 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 calibration stage, the power output to the inner ring heater by the inner ring power regulator is controlled.

[0032] The cavity assembly structure in the production stage and the test calibration stage of the present application is different. In the production stage, the inner ring power regulator, the outer ring power regulator, the outer ring PID controller and the outer ring temperature sensor need to be installed in the cavity, and the inner ring temperature sensor and the inner ring PID controller do not need to be installed. The power control of the inner ring power regulator is directly controlled 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 calibration stage.

[0033] The corresponding relationship between the output power of the inner and outer ring power regulators and the temperature change established in the test calibration stage includes the corresponding relationship between the temperature, the inner ring power regulator output power and the outer ring power regulator output power. The temperature in the corresponding relationship is obtained by detecting the temperature of the wafer inner and outer ring heater corresponding area through the independently installed inner and outer ring temperature sensors in the cavity in the test calibration stage. The output power of the inner and outer ring power regulators in the corresponding relationship comes from the control of the mutually independent inner and outer ring PID controllers in the cavity in the test calibration stage. Among them, the inner and outer ring PID controllers installed in the cavity in the test calibration stage respectively control the output power of the inner and outer ring power regulators according to the difference between the temperature detected by the inner and outer ring temperature sensors and the target temperature.

[0034] By comparing the component structure and temperature control mode in the test calibration stage and the actual production stage, it can be found that the scheme provided by the present application only needs to use one outer ring temperature sensor and one outer ring PID controller in the actual production stage, and the inner ring temperature sensor and the inner ring PID controller are saved. The temperature control mode is changed from independent control of the inner ring and the outer ring to cooperative control of the inner ring power regulator according to the established corresponding relationship. The scheme provided by the present application can realize accurate control of the inner ring and the outer ring temperature and make the distribution of the wafer surface temperature more uniform, and reduce the complexity of the system and the cost of the equipment.

[0035] Figure 2 The figure is a step flow diagram of the test calibration stage in an embodiment of the present application. In this embodiment, the control program can be written into the programmable logic controller (PLC) by the industrial computer, and the automatic control of each component in the test calibration stage is realized by the programmable logic controller to automatically complete the establishment and calibration of the corresponding relationship between the output power of the inner ring and outer ring power regulators and the temperature change according to the preset process steps.

[0036] In the test calibration stage, the accuracy of the measured temperature of the temperature sensor, the uniformity of the temperature, and the accuracy of the output power can be calibrated by using the thermocouple wafer (TC Wafer). The TC Wafer is a wafer embedded with high-precision temperature sensors, which can be used to measure the wafer surface temperature in real time and evaluate the uniformity of the wafer surface temperature, and can provide temperature data support for calibration to ensure the accuracy and reliability of the temperature detected by the temperature sensor and the output power of the inner and outer ring power regulators as much as possible.

[0037] Figure 3 The figure is a layout diagram of the TC Wafer used in calibration and the embedded temperature sensor in an embodiment of the present application. Each black dot in the figure represents a temperature sensor embedded on the wafer surface. There are a total of 17 temperature sensors (such as thermocouples) arranged uniformly from the center point to the outermost ring. The temperature at multiple positions on the wafer surface can be measured in real time by the temperature sensors embedded on the wafer surface of the TC Wafer, so as to obtain the temperature distribution of the entire wafer. In addition, the temperature dynamic changes such as temperature rise, temperature drop, constant temperature process, and delay time can also be captured.

[0038] The processing process of the test calibration stage is described in detail as follows: Step 201, performing initialization operation; The initialization includes initialization of each component in the cavity, such as initialization of the calibration array, initialization of the PID controller, power regulator, temperature sensor, heater and other component parameters and states.

[0039] The calibration array is used to record the target temperature after calibration, and is used to judge whether the corresponding target temperature has been calibrated.

[0040] Step 202, running the control program, starting heating; After the initialization operation is completed, the control program in the PLC is run, and under the control of the control program, the inner and outer ring power adjusters are simultaneously turned on, and the power output by the inner and outer ring power adjusters is controlled through the PID controller. The inner and outer ring heaters start heating, so that the temperature of the corresponding area of the inner and outer ring heaters gradually rises.

[0041] Step 203, judging whether the target temperature is in the calibration array? If not, step 204 is executed; if yes, step 205 is executed; Step 204, in the case that the target temperature is not in the calibration array, the target temperature is added to the calibration array, and then step 203 is executed; Step 205, in the case that the target temperature is in the calibration array, judging whether the target temperature has been calibrated? If yes, step 206 is executed; if not, step 207 is executed; Whether the calibration is completed can be recorded by marking the completion identifier in the data unit structure of the calibration array.

[0042] Step 206, judging whether re-calibration is needed? If yes, the target temperature calibration completion status is modified to an uncompleted status, and then step 205 is executed; otherwise, step 210 is executed; In some cases, re-calibration of the target temperature may be needed, for example, in the case of replacing the temperature sensor, power adjuster and other hardware devices. For the target temperature that needs to be re-calibrated, the re-calibration mark can be set to identify it.

[0043] Step 207, judging whether the current temperature average is less than the target temperature? If yes, step 208 is executed; if not, it means that the target temperature has been reached, and the calibration can be ended, and step 210 is executed; Step 208, reading the temperature and calculating the average temperature according to the preset period; In this step, the current wafer surface inner and outer ring temperature values are read in real time from the independently installed inner and outer ring temperature sensors (first and second temperature sensors), and the first average is obtained after calculating the average temperature.

[0044] In this process, the temperature values of multiple temperature sensors on the surface of the TC Wafer can be read in real time at the same time, and then the calibration average is obtained by averaging the multiple temperature values. Through the difference between the calibration average and the first average, the parameters of the PID controller can be adjusted through the control program to adjust the output power of the inner and outer ring power adjusters to realize the calibration of the corresponding relationship between the power output of the power adjuster and the average temperature.

[0045] The preset period for reading the temperature sensor to measure the temperature value in this step can be set by a configuration parameter, for example, can be set to 100 ms, 300 ms, etc. according to the physical characteristics of the device and application requirements.

[0046] After saving the average temperature value of the inner and outer power adjustors in step 209, return to step 207.

[0047] This step records the average temperature value of the corresponding area of the inner and outer ring heaters and the output power of the inner and outer ring power adjustors, thereby establishing the corresponding relationship between the output power of the inner and outer ring power adjustors and the temperature change.

[0048] In step 210, when the average temperature value is not less than the target temperature, the heating is ended.

[0049] When the current average temperature value is greater than or equal to the target temperature, the heating for the wafer can be stopped, and the target temperature calibration process can be stopped after the calibration target is completed.

[0050] Figure 4 The step flowchart in the production stage of an embodiment of the present application is shown. In the production stage, the programmable logic controller (PLC) can be used to automatically control the components in the cavity, reducing the influence of manual intervention, thereby 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 ring wafer, and the temperature signal is transmitted to the outer ring PID controller. The power of the outer ring power adjustor is adjusted and controlled by the outer ring PID controller, and the power of the inner ring power adjustor is output according to the corresponding relationship between the output power of the inner ring power adjustor and the output power of the outer ring power adjustor obtained in the test calibration stage, thereby simplifying the system structure and reducing the cost.

[0051] In step 401, read the corresponding relationship data between the output power of the inner and outer ring power adjustors and the temperature change after calibration; After the system is powered on and initialized in step, the running control program is loaded, and the control program reads the corresponding relationship data between the output power of the inner and outer ring power adjustors and the temperature change established and calibrated in the test calibration stage from the storage medium.

[0052] In step 402, start heating; Under the control of the control program, the inner and outer ring power adjustors are turned on at the same time, and the inner and outer ring heaters start heating, so that the temperature of the corresponding area of the inner and outer ring heaters gradually increases.

[0053] In step 403, determine whether the average temperature value is within the error range of the target temperature? If it is within the error range of the target temperature, execute step 406 to end the heating; if it is not within the error range of the target temperature, execute step 404. In the production state, before each wafer is put into the cavity to start heating, the temperature average value is set to a value lower than the target temperature, after starting heating, the system starts to read the temperature of the temperature sensor and calculate the average value at a preset period, and continuously loops to judge whether the temperature average value is within the error range of the target temperature.

[0054] Step 404, reading the temperature and calculating the average value at a preset period; In this step, the system will continuously loop to read the temperature detected by one or more outer ring temperature sensors at a preset period (for example, 100 ms), 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 (for example, 500 ms) and calculate the average temperature within the preset statistical window.

[0055] Step 405, the outer ring power regulator is controlled by the outer ring PID controller to heat, and the inner ring power regulator is controlled to output power according to the corresponding relationship, and then step 403 is executed; In this step, the outer ring PID controller controls the output power of the outer ring power regulator according to the average temperature, and the output 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 the temperature change established in the test calibration stage; After the current temperature average value is calculated, the temperature average value is transmitted to the outer ring PID controller, which controls the output power of the outer ring power regulator to the outer ring heater according to the difference between the temperature average value and the target temperature, and 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 according to the corresponding relationship between the output power of the inner and outer ring power regulators and the temperature change obtained in step 401, and transmits the information of the read output power of the inner ring power regulator to the inner ring power regulator, thereby controlling the output power of the inner ring power regulator.

[0056] Step 406, end heating when the temperature average value is not less than the target temperature.

[0057] The application innovatively separates the power control methods in the test calibration stage and the production stage, obtains the corresponding relationship between the output power of the inner and outer ring power regulators in the test calibration stage, and realizes the power control of the single PID controller based on the outer ring temperature sensor and the automatic control logic in the production stage according to the corresponding relationship, solving the problems of uneven temperature distribution, system complexity and high cost in the traditional semiconductor manufacturing cavity heating system.

[0058] Figure 5Figure 1 is a side view of a semiconductor cavity inner component structure according to an embodiment of the present application. In this embodiment, a heating lamp plate for mounting inner ring heaters and outer ring heaters is arranged above the wafer, and the heaters in this embodiment are halogen heating lamps. An outer ring temperature sensor is arranged above or below the wafer surface near the edge position, and the temperature sensor can be implemented using a thermocouple.

[0059] Figure 6 Figure 2 is a top view of a semiconductor cavity inner heating lamp plate according to an embodiment of the present application. The lamp plate is divided into an inner ring and an outer ring, and the plurality of inner ring heaters of the inner ring are electrically connected to an inner ring power regulator located outside the cavity, and the plurality of outer ring heaters of the outer ring are electrically connected to an outer ring power regulator located outside the cavity.

[0060] In another embodiment of the present application, an isolation portion is arranged below the inner ring heaters and the outer ring heaters, respectively, and an inner ring temperature sensor (first thermocouple) and an outer ring temperature sensor (second thermocouple) are arranged on the isolation portion, respectively, for detecting the temperature of the corresponding region of the inner ring heaters and the outer ring heaters. The purpose of arranging the isolation portion is to isolate the influence of the upper inner and outer ring heaters on the temperature sensors.

[0061] In another embodiment of the present application, the inner ring heaters and the outer ring heaters are respectively electrically connected to a corresponding inner ring DC power supply and an outer ring DC power supply, or the inner ring heaters and the outer ring heaters are respectively electrically connected to an inner ring power regulator and an outer ring power regulator.

[0062] In an embodiment of the present application, a first sidewall heater, a second sidewall heater, and a third sidewall heater are arranged 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 respectively electrically connected to a sidewall power regulator; The sidewall power regulator outputs power to the first sidewall heater, the second sidewall heater, and the third sidewall heater under the control of a sidewall PID controller; The sidewall PID controller controls the output power of the sidewall power regulator according to the difference between the sidewall temperature detected by a sidewall temperature sensor (which can be the average of three sidewall temperatures) and the target temperature.

[0063] By increasing the sidewall heaters, the heating speed of the cavity can be improved, and the non-uniformity of the wafer surface temperature due to the non-uniformity of the sidewall temperature of the cavity can also be avoided.

[0064] The technical solutions and technical effects of the present application are described below in combination with experimental data. In an embodiment of the present application, the TC Wafer is used for calibration in the test calibration stage, and the independent PID controller control strategy of the inner and outer rings is adopted to accurately obtain the output corresponding relationship of the inner and outer ring power adjusters. The target temperature is set to 120℃, and the PID controller parameters are determined after repeated debugging and optimization: the inner ring proportional coefficient Kp1=0.4, the integral coefficient Ki1=0.06, and the differential coefficient Kd1=0.08; the outer ring proportional coefficient Kp2=0.35, the integral coefficient Ki2=0.05, and the differential coefficient Kd2=0.1.

[0065] In the test calibration process, the inner and outer ring temperatures, the power adjuster output power, and the corresponding temperature average value are read every 100ms as a data collection unit every 3℃. By continuously heating and recording data in real time, the corresponding relationship of the temperature, the inner ring power adjuster output power, and the outer ring power adjuster output power is constructed, and the data in Table 1 is finally arranged. The corresponding relationship between the inner and outer ring power adjuster output power and the temperature change can be shown through Table 1, wherein the power adjuster output power can be represented by the percentage of the output power.

[0066] Table 1

[0067] In order to verify the effectiveness of the data obtained in the test calibration stage, the present application also verifies the cavity temperature control effect based on the corresponding relationship of the inner and outer ring power adjuster output power obtained in the test calibration stage before the cavity is put into actual production. In the verification, the outer ring PID controller dynamically adjusts the output power of the outer ring power adjuster according to the real-time temperature detected by the outer ring temperature sensor, and the inner ring power adjuster directly calls the corresponding relationship output power after calibration. In the experiment, the inner and outer ring temperature data is continuously collected every 100ms as a preset period interval, and the temperature change in Table 2 is obtained: Table 2

[0068] From the temperature change data in Table 2, it can be clearly seen that as the heating time advances, the inner and outer ring temperatures rapidly rise and gradually approach the target temperature 120℃. When the temperature approaches the target value, the PID control of the outer ring power adjuster and the power output based on the corresponding relationship of the inner and outer ring power adjuster output power after calibration cooperate with each other, so that the inner and outer ring temperatures remain stable near the target temperature, and the fluctuation range is controlled within ±1.5℃.

[0069] Detailed analysis was made on the temperature data collected in the production verification process, and the mean and standard deviation of temperature error were calculated. The results showed that the mean temperature of the inner ring was 119.8℃, and the standard deviation was 0.8℃; the mean temperature of the outer ring was 120.2℃, and the standard deviation was 0.9℃. The average error of the inner and outer ring temperatures from the target temperature 120℃ was 0.2℃ and 0.2℃ respectively, and the error rate was less than 0.2%, which was much smaller than the error standard of ±3℃ in the industry.

[0070] In summary, the output corresponding relationship of the inner and outer ring power adjuster established by the calibration experiment, combined with the control strategy in the production verification stage, can make the TC Wafer accurately reach the target temperature 120℃ in the heating process, and the temperature control is stable, the error is minimal, which fully proves that the scheme is accurate and feasible in practical application, has good reliability and practicability, and can be effectively applied to related production and manufacturing scenes.

[0071] Figure 7 The system structure diagram for production verification of the semiconductor cavity control method in an embodiment of the present application. The program for implementing the semiconductor cavity temperature control method provided by the present application can be loaded and run in the programmable logic controller (PLC) in the form of software and hardware modules, and the PLC is equivalent to a device or equipment for implementing the method provided by the present application. The device or equipment can be controlled by an industrial computer. The function of the PID controller can also be integrated in 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 uses a K-type thermocouple, Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. Accordingly, the computer program can be stored in a non-volatile computer readable storage medium, and when the computer program is executed, the method of any one of the above embodiments can be implemented. In the embodiments provided in the present application, any reference to memory, storage, database or other medium can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration but not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM) and memory bus dynamic RAM (RDRAM), etc.

[0072] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Those skilled in the art should understand that the present application includes but is not limited to the contents described in the above specific embodiments and the accompanying drawings. Any modification that does not deviate from the functional and structural principles of the present application will be included in the scope of the claims.

Claims

1. A method of temperature control of a semiconductor cavity, characterized by, The semiconductor cavity temperature control method comprises: In the production stage after the cavity is put into production, the temperature of the corresponding area of the wafer outer ring heater is detected by the outer ring temperature sensor installed in the cavity, the output power of the outer ring power regulator is controlled by the PID controller according to the difference between the detected temperature and the target temperature, and the output power of the inner ring power regulator to the inner ring heater is controlled 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 calibration stage.

2. The semiconductor cavity temperature control method according to claim 1, wherein The corresponding relationship comprises the corresponding relationship among the temperature, the output power of the inner ring power regulator and the output power of the outer ring power regulator, the temperature in the corresponding relationship is obtained by detecting the temperature of the corresponding area of the wafer inner and outer ring heaters by the independently installed inner and outer ring temperature sensors in the cavity, the output power of the inner and outer ring power regulators in the corresponding relationship is respectively controlled by the mutually independent inner and outer ring PID controllers, and the output power of the inner and outer ring power regulators is respectively independently controlled by the inner and outer ring PID controllers according to the difference between the temperature detected by the inner and outer ring temperature sensors and the target temperature.

3. The semiconductor cavity temperature control method according to claim 2, wherein In the test calibration stage, the inner and outer ring temperature sensors and the corresponding relationship between the output power of the inner and outer ring power regulators and the temperature change are calibrated by using a thermocouple wafer.

4. The semiconductor cavity temperature control method according to claim 2, wherein The temperature detected by the temperature sensor is read at a preset period and the average temperature is calculated; The PID controller controls the output power of the power regulator according to the difference between the average temperature detected by the temperature sensor and the target temperature.

5. The semiconductor cavity temperature control method according to any one of claims 1 to 4, wherein The temperature control process in the test calibration stage and the production stage is automatically controlled by using a programmable logic controller.

6. A semiconductor cavity temperature control device for temperature control of a semiconductor cavity in a production phase, characterized by The semiconductor cavity temperature control device comprises: The inner ring heater is electrically connected with the inner ring power regulator and is used for heating the inner ring of the wafer under the control of the inner ring power regulator; The outer ring heater is electrically connected with the outer ring power regulator and is used for heating the outer ring of the wafer under the control of the outer ring power regulator; The outer ring temperature sensor is signal-connected with the outer ring PID controller and is used for detecting the temperature of the corresponding area of the wafer outer ring heater and transmitting the detected temperature to the outer ring PID controller; The outer ring PID controller is signal-connected with the outer ring temperature sensor and the outer ring power regulator respectively and is used for controlling the output power of the outer ring power regulator according to the difference between the temperature of the corresponding area of the wafer outer ring heater detected by the outer ring temperature sensor and the target temperature; The outer ring power regulator is used for outputting power to the outer ring heater under the control of the outer ring PID controller; The inner ring power regulator is used for outputting power to the inner ring heater 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 calibration stage.

7. The semiconductor cavity temperature control apparatus of claim 6, wherein The semiconductor cavity assembly structure in the production stage is different from the semiconductor cavity assembly structure in the test calibration stage; The semiconductor cavity assembly structure in the test calibration stage further comprises: The inner ring temperature sensor is connected with the inner ring PID controller in signal and is used for detecting the temperature of the corresponding area of the inner ring heater and transmitting the detected temperature to the inner ring PID controller. The inner ring PID controller is connected with the inner ring temperature sensor and the inner ring power regulator in signal and is used for controlling 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. The inner ring power regulator of the test calibration stage is used for outputting power to the inner ring heater under the control of the inner ring PID controller. The semiconductor cavity assembly structure of the test calibration stage further comprises: The relationship construction module is used for reading the temperature detected by the inner and outer ring temperature sensors and calculating the average temperature at a preset period, recording 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 establishing the corresponding relationship between the output power of the inner and outer ring power regulators and the temperature change.

8. The semiconductor cavity temperature control device according to claim 7, wherein, The 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 and are used for detecting the temperature of the corresponding area of the inner ring heater and the outer ring heater respectively.

9. The semiconductor cavity temperature control apparatus of claim 6 or 7, wherein, The semiconductor cavity further comprises: The first side wall heater, the second side wall heater and the third side wall heater are used for heating the side wall area of the cavity, and the first side wall heater, the second side wall heater and the third side wall heater are electrically connected to the side wall power regulator respectively. The side wall temperature sensor is used for detecting the side wall temperature. The side wall power regulator is used for outputting power to the first side wall heater, the second side wall heater and the third side wall heater under the control of the side wall PID controller. The side wall PID controller controls the output power of the side wall power regulator according to the difference between the temperature detected by the side wall temperature sensor and the target temperature.

10. A computer readable medium having stored thereon a computer program, characterized in that, The computer program is executed by the program execution unit to realize the semiconductor cavity temperature control method in any one of claims 1 to 4.

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