A method for controlling the temperature rise rate of a semiconductor device heating plate

Abstract

The present invention discloses a method for controlling the rising temperature rate of a semiconductor device heating disk, by dividing a complete heating process into a plurality of heating sub-processes, obtaining the actual temperature curve of each heating sub-process, and then obtaining the trend change point on the expected temperature curve according to the expected temperature curve, and when the number of trend change points is greater than TS / T, determining the adjustment interval of the PID controller, and adjusting the PID control parameters within the adjustment interval of each PID controller, and heating the semiconductor heating disk according to the current temperature of the heating disk of the last adjusted PID controller and the heating target temperature, so as to realize the control of the rising temperature rate of the semiconductor device heating disk. The present invention controls the heating rate by introducing multiple groups of PID parameters to switch under different temperature conditions, which can significantly improve the fitting degree of the heating expected curve and the heating actual curve.

Description

Technical Field

[0001] The invention relates to the field of semiconductor manufacturing, and in particular to a method for controlling the rising temperature rate of a heating disk of a semiconductor device. Background Art

[0002] Temperature control of semiconductor equipment heating plates is crucial to process stability and the quality of the final product. Current semiconductor equipment heating plate systems generally use PID for temperature control. For example, if a process temperature requires 400 degrees, the output of the PID model is used to control the heater. Although the temperature can eventually be stabilized at 400 degrees, it depends entirely on the free output of the PID model. For situations where the heating rate needs to be controlled, PID control alone cannot achieve rate control. Summary of the invention

[0003] The invention discloses a method for controlling the rising temperature rate of a heating plate of a semiconductor device to overcome the above technical problems.

[0004] In order to achieve the above object, the technical solution of the present invention is:

[0005] A method for controlling the temperature rise rate of a semiconductor device heating plate comprises the following steps:

[0006] S1: acquiring the total number of heating sub-processes for heating the heating disk of the semiconductor device according to the expected rate of increase of the temperature of the heating disk of the semiconductor device;

[0007] S2: according to the total number of heating sub-processes, the starting temperature of the first heating sub-process, i.e., the current temperature of the heating plate, and the target temperature calculation formula of the heating sub-process, the target temperature of the first heating sub-process is obtained;

[0008] S3: according to the initial PID controller based on the initial PID control parameters, according to the starting temperature of the first heating sub-process, the execution time of the heating sub-process and the target temperature of the first heating sub-process, the actual temperature of the heating disk at the end of the first heating sub-process and the actual temperature curve of the first heating sub-process are obtained; wherein the actual temperature of the heating disk at the end of the first heating sub-process is the starting temperature of the heating disk in the second heating sub-process;

[0009] S4: based on the actual temperature of the heating disk at the end of the ns-1th heating sub-process, that is, the starting temperature of the heating disk at the ns-1th heating sub-process, repeat S2-S3 to obtain the target temperature at the end of the ns-1th heating sub-process; to obtain the actual temperature of the heating disk at the end of the ns-1th heating sub-process and the actual temperature curve of the ns-1th heating sub-process; until the actual temperature of the heating disk at the end of the NS-1th heating sub-process and the actual temperature curve of the NS-1th heating sub-process are obtained; wherein ns represents the index number of the heating sub-process, ns=1,…,NS; NS represents the total number of heating sub-processes;

[0010] S5: acquiring the actual temperature of the heating disk at the end of the NSth heating sub-process and the actual temperature curve of the NSth heating sub-process according to the initial PID controller based on the initial PID control parameters, the starting temperature of the NSth heating sub-process, the execution time of the heating sub-process and the heating target temperature of the heating disk of the semiconductor device;

[0011] S6: according to the actual temperature curve of the 1st heating sub-process, …, the actual temperature curve of the nsth heating sub-process, …, the actual temperature curve of the NS-1th heating sub-process, and the actual temperature curve of the NSth heating sub-process, a complete actual temperature curve is obtained;

[0012] S7: according to the complete actual temperature curve and the expected temperature curve for heating the heating plate of the semiconductor device, obtaining a trend change point on the expected temperature curve;

[0013] S8: When the number of the trend change points is greater than TS / T, determine the area between two adjacent trend change points as the adjustment interval of the PID controller; and adjust the PID controller parameters based on the adjustment interval of the PID controller to obtain the adjusted PID controller parameters of the adjustment interval of the PID controller; execute S9;

[0014] The PID control parameters include integral gain, differential gain and proportional gain;

[0015] Otherwise, when the number of the trend change points is not greater than TS / T, the PID controller parameters at this time are used as the final PID controller parameters, and S10 is executed;

[0016] Among them, T S represents the execution time of the heating subprocess, and T represents the sampling period;

[0017] S9: Based on the adjusted PID controller parameters in the adjustment interval of the PID controller, repeatedly execute S3-S8 until the number of trend change points is no more than TS / T, and use the adjusted PID controller parameters in the adjustment interval of the PID controller at this time as the final PID controller parameters;

[0018] S10: According to the last PID controller parameters, the last PID controller is obtained to heat the semiconductor heating plate according to the last PID controller, the current temperature of the heating plate and the heating target temperature, so as to control the temperature rise rate of the semiconductor device heating plate.

[0019] Furthermore, the method for obtaining the adjusted PID controller parameters of the adjustment interval of the PID controller is as follows:

[0020] S801: Set the initial integral gain and differential gain to zero; and initialize the proportional gain;

[0021] S802: increasing the initialized proportional gain according to the set step size to obtain an adjusted proportional gain, so as to obtain an adjusted PID controller based on the adjusted proportional gain and the initial integral gain and differential gain;

[0022] S803: According to the actual temperature at the start time of the adjustment interval of the PID controller, the target temperature at the end time of the adjustment interval of the PID controller, and the adjusted PID controller, obtaining the actual temperature output by the adjusted PID controller;

[0023] S804: When the difference between the actual temperature output by the adjusted PID controller and the expected temperature meets the stable oscillation condition, the adjusted proportional gain at this time is recorded as the critical proportional gain Kpu; execute S805;

[0024] Otherwise, based on the adjusted proportional gain, S802-S803 are repeatedly executed;

[0025] S805: Obtain adjusted PID control parameters according to the critical proportional gain Kpu.

[0026] Furthermore, the total number of the heating sub-processes is obtained as follows:

[0027]

[0028] Where: N S Represents the total number of heating sub-processes; T e Indicates the heating target temperature of the semiconductor device; T c Indicates the current temperature of the system; T S Represents the execution time of the heating subprocess; V tIndicates the desire to control the rate of heating.

[0029] Furthermore, the calculation formula of the target temperature of the heating sub-process is as follows:

[0030] Tm ns =Tc ns +ΔT ns

[0031]

[0032] Where: Tm ns represents the target temperature of the nsth heating sub-process; ns represents the index number of the heating sub-process, ns=1,...,NS; NS represents the total number of heating sub-processes; Tc ns represents the starting temperature of the nsth heating subprocess; ΔT ns represents the temperature increment of the nsth heating subprocess; T e Indicates the heating target temperature of the semiconductor device.

[0033] Furthermore, the method for obtaining the trend change point on the expected temperature curve is as follows:

[0034] S71: Sampling is performed along the direction of increasing time according to the set sampling period, and sampling is performed on the complete actual temperature curve and the expected temperature curve respectively, and the actual temperature S on the complete actual temperature curve corresponding to the i-th sampling point is obtained. i and the desired temperature Q on the desired temperature curve i ; To obtain the temperature difference X of the i-th sampling point i ;

[0035] S72: If the temperature difference X of the i-th sampling point i If the temperature difference X is less than the set threshold, the temperature difference X i The points on the expected temperature curve corresponding to the i-th sampling point that is less than the set threshold are marked as POINTe_1, POINTe_2, ..., POINTe_p-1, POINTe_p, ...; p represents the temperature difference X i The index number of the point on the expected temperature curve corresponding to the i-th sampling point that is less than the set threshold; POINTe_p represents the p-th temperature difference X on the expected temperature curve. i Points that are less than the set threshold;

[0036] Otherwise, if the temperature difference x of the i-th sampling point i If the temperature difference X is not less than the set threshold, the temperature difference X iThe points on the expected temperature curve corresponding to the i-th sampling point that is not less than the set threshold are marked as POINTn_1, POINTn_2, ..., POINTn_q, ...; q represents the temperature difference X i The index number of the point on the expected temperature curve corresponding to the i-th sampling point that is not less than the set threshold; POINTn_q represents the q-th temperature difference value X on the expected temperature curve. i Points not less than the set threshold;

[0037] S73: If the p-1th temperature difference X on the expected temperature curve i The point POINTe_p-1 which is less than the set threshold value and the pth temperature difference X on the expected temperature curve i Between the points POINTe_p that are less than the set threshold, there is the qth temperature difference X on the expected temperature curve. i If the number of points not less than the set threshold is greater than TS / T, the p-1th temperature difference X on the expected temperature curve is i The temperature difference X between the point POINTe_p-1 which is less than the set threshold and the pth temperature on the expected temperature curve i Points POINTe_p that are smaller than the set threshold are determined as trend change points;

[0038] Among them, T S Represents the execution time of the heating sub-process; T represents the set sampling period.

[0039] Furthermore, the formula used to obtain the adjusted PID control parameters is as follows:

[0040] Kp'=0.6Kpu

[0041] Ki'=2Kp / Tu

[0042] Kd'=Kp*Tu / 8

[0043] Among them, Kpu represents the critical proportional gain; Kp represents the proportional gain; Tu represents the stable oscillation cycle time; Ki' represents the adjusted integral gain, Kd' represents the adjusted differential gain, and Kp' represents the adjusted proportional gain.

[0044] Beneficial effect: A method for controlling the rising temperature rate of a semiconductor device heating disk of the present invention divides the complete heating process into multiple heating sub-processes, obtains the actual temperature curve of each heating sub-process, obtains the complete actual temperature curve, and then obtains the trend change points on the expected temperature curve according to the expected temperature curve. When the number of trend change points is greater than TS / T, the adjustment interval of the PID controller is determined, and the PID control parameters are adjusted within the adjustment interval of each PID controller. The semiconductor heating disk is heated according to the current temperature of the heating disk of the last adjusted PID controller and the heating target temperature, so as to control the rising temperature rate of the semiconductor device heating disk. The present invention controls the heating rate by introducing multiple groups of PID parameters to switch under different temperature conditions, which can significantly improve the fitting degree of the expected heating curve and the actual heating curve. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0046] Figure 1 A flow chart of a method for controlling the temperature rise rate of a semiconductor device heating plate of the present invention;

[0047] Figure 2 It is a schematic diagram comparing an actual temperature curve outputted by a conventional PID controller and an expected temperature curve in an embodiment of the present invention;

[0048] Figure 3 It is a schematic diagram of comparing the actual temperature curve and the expected temperature curve after heating in a heating sub-interval manner in an embodiment of the present invention;

[0049] Figure 4 It is the representation of the trend change point in the curve comparison diagram in the embodiment of the present invention;

[0050] Figure 5 A schematic diagram showing a comparison between an actual temperature curve output by a PID controller using the adjustment method of the PID controller proposed in an embodiment of the present invention and an expected temperature curve;

[0051] Figure 6 It is a schematic diagram of the structure of a heating plate of a semiconductor device in an embodiment of the present invention. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] This embodiment introduces a method for controlling the temperature rise rate of a semiconductor device heating plate. Figure 1 As shown, the following steps are included:

[0054] S1: acquiring the total number of heating sub-processes for heating the heating disk of the semiconductor device according to the expected rate of increase of the temperature of the heating disk of the semiconductor device;

[0055] Preferably, the total number of the heating sub-processes is obtained as follows:

[0056] Specifically, according to the definition of speed, the heating speed can be defined as the increment of temperature per unit time, so adjusting the temperature rise rate of the semiconductor device heating plate is equivalent to adjusting the increment of temperature on the semiconductor device heating plate per unit time, that is, each unit time can be regarded as a heating sub-process;

[0057]

[0058] Where: N S Represents the total number of heating sub-processes; T e Indicates the heating target temperature of the semiconductor device; T c Indicates the current temperature of the system; T S Represents the execution time of the heating subprocess, i.e., unit time; V t Indicates the desire to control the rate of heating;

[0059] Specifically, T S It is set according to the specific requirements of the heating speed: In this embodiment, if the heating rate to be achieved is required to rise by 0.2 degrees per second, 1 second is the time unit of the rate requirement, so T S Assuming 1 second, if the heating rate requires a rise of 0.2 degrees every 20 seconds, then T S The value is 20;

[0060] S2: according to the total number of heating sub-processes, the starting temperature of the first heating sub-process, that is, the current temperature of the heating plate, and the calculation formula of the target temperature of the heating sub-process, the target temperature of the first heating sub-process is obtained;

[0061] Preferably, the target temperature calculation formula of the heating sub-process is as follows:

[0062] Tm ns =Tc ns +ΔT ns

[0063]

[0064] Where: Tm ns represents the target temperature of the nsth heating sub-process; ns represents the index number of the heating sub-process, ns=1,...,NS; NS represents the total number of heating sub-processes; Tc ns represents the starting temperature of the nsth heating subprocess; ΔT ns represents the temperature increment of the nsth heating subprocess; T e Indicates the heating target temperature of the semiconductor device.

[0065] S3: according to the initial PID controller based on the initial PID control parameters, according to the starting temperature of the first heating sub-process, the execution time of the heating sub-process and the target temperature of the first heating sub-process, the actual temperature of the heating disk at the end of the first heating sub-process and the actual temperature curve of the first heating sub-process are obtained; wherein the actual temperature of the heating disk at the end of the first heating sub-process is the starting temperature of the heating disk in the second heating sub-process;

[0066] Specifically, the starting temperature of the first heating sub-process, the target temperature of the first heating sub-process and the execution time of the heating sub-process are input into the initial PID controller determined by the initial PID control parameters, and the PID controller starts to control the heating of the heating plate, and obtains the actual temperature of the heating plate at the end of the first heating sub-process; at the same time, the actual temperature curve of the first heating sub-process is drawn;

[0067] S4: based on the actual temperature of the heating disk at the end of the ns-1th heating sub-process, that is, the starting temperature of the heating disk at the ns-1th heating sub-process, repeat S2-S3 to obtain the target temperature at the end of the ns-1th heating sub-process; to obtain the actual temperature of the heating disk at the end of the ns-1th heating sub-process and the actual temperature curve of the ns-1th heating sub-process; until the actual temperature of the heating disk at the end of the NS-1th heating sub-process and the actual temperature curve of the NS-1th heating sub-process are obtained; wherein ns represents the index number of the heating sub-process, ns=1,…,NS; NS represents the total number of heating sub-processes;

[0068] Specifically, the starting temperature of the heating plate at the nsth heating sub-process, the target temperature at the end of the nsth heating sub-process, and the execution time of the heating sub-process are input into the initial PID controller determined by the initial PID control parameters, and the PID controller starts to control the heating of the heating plate, and obtains the actual temperature of the heating plate at the end of the nsth heating sub-process; at the same time, the actual temperature curve of the nsth heating sub-process is drawn;

[0069] S5: acquiring the actual temperature of the heating plate at the end of the NSth heating sub-process and the actual temperature curve of the NSth heating sub-process according to the initial PID controller based on the initial PID control parameters, the starting temperature of the NSth heating sub-process, the execution time of the heating sub-process and the final heating target temperature of the semiconductor device;

[0070] S6: according to the actual temperature curve of the 1st heating sub-process, …, the actual temperature curve of the nsth heating sub-process, …, the actual temperature curve of the NS-1th heating sub-process, and the actual temperature curve of the NSth heating sub-process, a complete actual temperature curve is obtained;

[0071] Specifically, the actual temperature curve of the first heating sub-process, ..., the actual temperature curve of the nsth heating sub-process, ..., the actual temperature curve of the NSth heating sub-process are spliced ​​in the same coordinate system, so that the complete actual temperature curve of the entire heating process can be obtained;

[0072] S7: according to the complete actual temperature curve and the expected temperature curve for heating the heating plate of the semiconductor device, obtaining a trend change point on the expected temperature curve;

[0073] Preferably, the method for obtaining the trend change point on the expected temperature curve is as follows:

[0074] S71: along the direction of time increase, sampling is performed according to the set sampling period (T=TS / 5), sampling is performed on the complete actual temperature curve and the expected temperature curve respectively, and the actual temperature S on the complete actual temperature curve corresponding to the i-th sampling point is obtained. i and the desired temperature Q on the desired temperature curve i ; To obtain the temperature difference X of the i-th sampling point i ;

[0075] Specifically, the temperature difference X of the i-th sampling point i Get as follows:

[0076] X i =| Q i -S i |

[0077] Among them, |·| represents absolute value operation;

[0078] S72: If the temperature difference X of the i-th sampling point i Less than the set threshold (Q i *5%o), then along the direction of time increase, the temperature difference X i The points on the expected temperature curve corresponding to the i-th sampling point that is less than the set threshold are marked as POINTe_1, POINTe_2, ..., POINTe_p-1, POINTe_p, ...; p represents the temperature difference X i The index number of the point on the expected temperature curve corresponding to the i-th sampling point that is less than the set threshold; POINTe_p represents the p-th temperature difference X on the expected temperature curve. i Points that are less than the set threshold;

[0079] Otherwise, if the temperature difference X of the i-th sampling point i If the temperature difference X is not less than the set threshold, the temperature difference X i The points on the expected temperature curve corresponding to the i-th sampling point that is not less than the set threshold are marked as POINTn_1, POINTn_2, ..., POINTn_q, ...; q represents the temperature difference X i The index number of the point on the expected temperature curve corresponding to the i-th sampling point that is not less than the set threshold; POINTn_q represents the q-th temperature difference value X on the expected temperature curve. i Points not less than the set threshold;

[0080] S73: If the p-1th temperature difference X on the expected temperature curve i The point POINTe_p-1 which is less than the set threshold value and the pth temperature difference X on the expected temperature curve i Between the points POINTe_p that are less than the set threshold, there is the qth temperature difference X on the expected temperature curve. i If the number of points not less than the set threshold is greater than TS / T, the p-1th temperature difference X on the expected temperature curve is i The temperature difference X between the point POINTe_p-1 which is less than the set threshold and the pth temperature on the expected temperature curve i Points POINTe p that are smaller than the set threshold are determined as trend change points;

[0081] Among them, T S Indicates the execution time of the heating subprocess; T indicates the set sampling period;

[0082] S8: When the number of the trend change points is greater than TS / T, determine the area between two adjacent trend change points as the adjustment interval of the PID controller; and adjust the PID controller parameters based on the adjustment interval of the PID controller to obtain the adjusted PID controller parameters of the adjustment interval of the PID controller; execute S9;

[0083] Among them, PID control parameters include integral gain Ki, differential gain Kd, and proportional gain Kp;

[0084] Otherwise, when the number of the trend change points is not greater than TS / T, the PID controller parameters at this time are used as the final PID controller parameters, and S10 is executed;

[0085] Among them, T S represents the execution time of the heating subprocess; T represents the sampling period;

[0086] Specifically, since TS is the time of a heating sub-interval, if the number of trend change points is greater than TS / T, there is a heating sub-interval whose time is at the trend change point. If the number of trend change points is not greater than TS / T, it is judged that the heating sub-interval has a trend change, but it will converge to the expected temperature curve. Therefore, this embodiment does not discuss the situation when the number of trend change points is not greater than TS / T.

[0087] Preferably, the method for obtaining the adjusted PID controller parameters of the adjustment interval of the PID controller is as follows:

[0088] S801: Set the initial integral gain Ki and differential gain Kd to zero; and initialize the proportional gain Kp;

[0089] S802: increasing the value of the initialized proportional gain Kp according to a set step size to obtain an adjusted proportional gain, so as to obtain an adjusted PID controller based on the adjusted proportional gain and the initial integral gain and differential gain;

[0090] S803: Obtaining the actual temperature output by the adjusted PID controller according to the actual temperature at the start time of the adjustment interval of the PID controller, the target temperature at the end time of the adjustment interval of the PID controller, the adjusted PID controller, and the duration of the adjustment interval of the PID controller;

[0091] S804: When the difference between the actual temperature output by the adjusted PID controller and the expected temperature meets the stable oscillation condition, the adjusted proportional gain Kp at this time is recorded as the critical proportional gain Kpu; execute S805;

[0092] Otherwise, based on the adjusted proportional gain, S802-S803 are repeatedly executed;

[0093] Specifically, the stable oscillation conditions of this embodiment are:

[0094] When the error e(t) = |r(t)-y(t)| between the expected temperature r(t) of the system at time t and the actual temperature y(t) output by the adjusted PID controller shows a sinusoidal change, and the difference between the absolute value of the maximum difference and the absolute value of the minimum difference in three consecutive cycles is less than one percent of the absolute value of the maximum value (or the absolute value of the minimum value), the smaller value between the absolute value of the maximum value and the absolute value of the minimum value is taken. If the set temperature is 100 degrees, and the actual temperature changes as follows: 98, 99, 100, 101, 102, 101, 100, 99, 98, 99, 100, 101, 102, 101, 100, 99, 98, 99, 100, 101, 102, 101, 100, 99, 98, then the difference e(t) is 2, 1, 0, -1, -2, -1, 0, 1, 2, 1, 0, -1, -2, -1, 0, 1, 2, 1, 0, -1, -2, -1, 0, 1, 2. The difference between the absolute value of the maximum value |2| and the absolute value of the minimum value |-2| for three consecutive periods is 0, which is less than one percent of the absolute value of the maximum value;

[0095] S805: According to the critical proportional gain Kpu, obtaining adjusted PID control parameters, including Ki, Kd and Kp;

[0096] Preferably, the formula used to obtain the adjusted PID control parameters Ki, Kd and Kp is as follows:

[0097] Kp'=0.6Kpu

[0098] Ki'=2Kp / Tu

[0099] Kd'=Kp*Tu / 8

[0100] Among them, Kpu represents the critical proportional gain; Kp represents the proportional gain; Tu represents the stable oscillation cycle time; Ki' represents the adjusted integral gain, Kd' represents the adjusted differential gain, and Kp' represents the adjusted proportional gain.

[0101] Specifically, the PID controller model established in this embodiment is as follows:

[0102]

[0103] Where: u(t) represents the output of the PID controller; K prepresents the proportional gain, corresponding to the current value of the error; e(t) represents the error of the controlled system, that is, the difference between the set value r(t) and the actual value y(t): e(t) = r(t)-y(t); r(t) represents the set value of the controlled system; y(t) represents the actual value of the controlled system; K i represents the integral gain, which corresponds to the accumulated value of the error of the controlled system; t represents time; Kd represents the differential gain, which corresponds to the rate of change of the error of the controlled system;

[0104] in:

[0105] Proportional control: Adjust according to the current error size, the formula is u p (t) = K p e(t),u p (t) represents the component calculated by proportional control in the output u(t) of PID regulation;

[0106] Integral control: Adjust according to the accumulation of errors, mainly used to eliminate steady-state errors. The formula is:

[0107]

[0108] Where: u i (t) represents the component calculated by integral control in the output u(t) of PID regulation; K i It indicates the integral gain;

[0109] Differential control: Adjust according to the rate of change of error, mainly used to predict the changing trend of error.

[0110] The formula is

[0111]

[0112] Where: u d (t) represents the component calculated by the differential control in the output u(t) of PID regulation;

[0113] S9: Based on the adjusted PID controller parameters in the adjustment interval of the PID controller, repeatedly execute S3-S8 until the number of trend change points is no more than TS / T, and use the adjusted PID controller parameters in the adjustment interval of the PID controller at this time as the final PID controller parameters;

[0114] S10: According to the last PID controller parameters, the last PID controller is obtained to heat the semiconductor heating plate according to the last PID controller, the current temperature of the heating plate and the heating target temperature, so as to control the temperature rise rate of the semiconductor device heating plate.

[0115] Specifically, the initial temperature and target temperature of the heating plate are input, and the heating of the heating plate is controlled according to the final PID controller to achieve control of the temperature rise rate of the heating plate.

[0116] A specific embodiment of the present invention is as follows:

[0117] In this example, 400 degrees is the final target temperature, and the adjusted parameters are Kp = 2.0, Ki = 0.6, Kd = 0.3. The curve after adjustment using a conventional PID controller is shown in the figure:

[0118] like Figure 2 It can be seen that although the temperature finally stabilized at the set 400 degrees, the actual heating speed was much faster than the expected heating speed, and the entire heating process did not follow the expected curve.

[0119] In this example, 400 degrees is the final target temperature, the current temperature is 23 degrees, the expected heating speed is 0.2 degrees per second, and the execution time of each sub-process is 1 second. The number of heating sub-processes is 1885. The target temperature of the first heating sub-process is 23.2 degrees. After 1 second, the second heating sub-process is entered, and the target temperature is 23.4 degrees until the last heating sub-process. The adjusted curve is shown in the figure below:

[0120] like Figure 3 It can be seen that the actual temperature heating rate has been preliminarily controlled, but there is still a significant difference from the expected curve. It can be found that there are repeated interspersals between the actual curve and the expected curve, and there are several overshoot or slow response intervals, such as Figure 4 As shown:

[0121] A PID overshoot zone Z1 is formed between the temperature starting point and the trend point P1, a PID overshoot zone Z2 is formed between P1 and P2, a PID slow response zone Z3 is formed between P2 and P3, a PID overshoot zone Z4 is formed between P3 and P4, and a PID slow response zone Z5 is formed between P4 and the heating temperature end point. According to the above PID adjustment method, when the temperature value is within the Z1 interval below the range of P1, the set value is set to P1 to adjust the optimal PID parameters. Similarly, the optimal PID parameters of Z2 to Z5 are adjusted respectively. In this embodiment:

[0122] Point P1 is 72.0 degrees

[0123] Point P2 is 175.6 degrees

[0124] Point P3 is 230.1 degrees

[0125] Point P4 is 366.3 degrees

[0126] The corresponding PID interval parameters are as follows:

[0127] Z1: Kp, 1.2; Ki, 0.5; Kd, 0.3;

[0128] Z2: Kp, 1.6; Ki, 0.5; Kd, 0.3;

[0129] Z3: Kp, 2.5; Ki, 0.6; Kd, 0.3;

[0130] Z4: Kp, 3.2; Ki, 0.7; Kd, 0.3;

[0131] Z5: Kp, 2.8; Ki, 0.5; Kd, 0.3;

[0132] After heating operation, the PID model parameters are switched according to the current temperature range, and the following curve is finally obtained: Figure 5 As shown;

[0133] It can be seen that the degree of fit has been significantly improved compared with before

[0134] The present invention can be applied in situations where the heating speed needs to be controlled and there are high requirements for the fitting of the desired heating curve and the actual heating curve. This embodiment is described by taking a wafer heating plate as an example. The schematic diagram of the semiconductor device heating plate structure of this embodiment is as follows: Figure 6 As shown: the heating system of the wafer heating plate is composed of a heating wire, a temperature sensor, an SSR and a controller, and the heating wire is arranged in the wafer heating plate. The temperature sensor is arranged in the heating plate, and the collected temperature is returned to the controller. The controller outputs the SSR according to the result calculated by the algorithm of this embodiment, so as to achieve the purpose of temperature control.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling the temperature rise rate of a semiconductor device heating plate, characterized in that: The steps include: S1: acquiring the total number of heating sub-processes for heating the heating disk of the semiconductor device according to the expected rate of increase of the temperature of the heating disk of the semiconductor device; S2: according to the total number of heating sub-processes, the starting temperature of the first heating sub-process, i.e., the current temperature of the heating plate, and the target temperature calculation formula of the heating sub-process, the target temperature of the first heating sub-process is obtained; S3: according to the initial PID controller based on the initial PID control parameters, according to the starting temperature of the first heating sub-process, the execution time of the heating sub-process and the target temperature of the first heating sub-process, the actual temperature of the heating disk at the end of the first heating sub-process and the actual temperature curve of the first heating sub-process are obtained; wherein the actual temperature of the heating disk at the end of the first heating sub-process is the starting temperature of the heating disk in the second heating sub-process; S4: based on the actual temperature of the heating disk at the end of the ns-1th heating sub-process, that is, the starting temperature of the heating disk at the ns-1th heating sub-process, repeat S2-S3 to obtain the target temperature at the end of the ns-1th heating sub-process; to obtain the actual temperature of the heating disk at the end of the ns-1th heating sub-process and the actual temperature curve of the ns-1th heating sub-process; until the actual temperature of the heating disk at the end of the NS-1th heating sub-process and the actual temperature curve of the NS-1th heating sub-process are obtained; wherein ns represents the index number of the heating sub-process, ns=1,…,NS; NS represents the total number of heating sub-processes; S5: acquiring the actual temperature of the heating disk at the end of the NSth heating sub-process and the actual temperature curve of the NSth heating sub-process according to the initial PID controller based on the initial PID control parameters, the starting temperature of the NSth heating sub-process, the execution time of the heating sub-process and the heating target temperature of the heating disk of the semiconductor device; S6: according to the actual temperature curve of the 1st heating sub-process, …, the actual temperature curve of the nsth heating sub-process, …, the actual temperature curve of the NS-1th heating sub-process, and the actual temperature curve of the NSth heating sub-process, a complete actual temperature curve is obtained; S7: according to the complete actual temperature curve and the expected temperature curve for heating the heating plate of the semiconductor device, obtaining a trend change point on the expected temperature curve; The method for obtaining the trend change point on the expected temperature curve is as follows: S71: Sampling is performed along the direction of increasing time according to the set sampling period, and sampling is performed on the complete actual temperature curve and the expected temperature curve respectively, and the actual temperature S on the complete actual temperature curve corresponding to the i-th sampling point is obtained. i and the desired temperature Q on the desired temperature curve i ; To obtain the temperature difference X of the i-th sampling point i ; S72: If the temperature difference X of the i-th sampling point i If the temperature difference X is less than the set threshold, the temperature difference X i The points on the expected temperature curve corresponding to the i-th sampling point that is less than the set threshold are marked as POINTe_1, POINTe_2, ..., POINTe_p-1, POINTe_p, ...; p represents the temperature difference X i The index number of the point on the expected temperature curve corresponding to the i-th sampling point that is less than the set threshold; POINTe_p represents the p-th temperature difference X on the expected temperature curve. i Points that are less than the set threshold; Otherwise, if the temperature difference X of the i-th sampling point i If the temperature difference X is not less than the set threshold, the temperature difference X i The points on the expected temperature curve corresponding to the i-th sampling point that is not less than the set threshold are marked as POINTn_1, POINTn_2, ..., POINTn_q, ...; q represents the temperature difference X i The index number of the point on the expected temperature curve corresponding to the i-th sampling point that is not less than the set threshold; POINTn_q represents the q-th temperature difference value X on the expected temperature curve. i Points not less than the set threshold; S73: If the p-1th temperature difference X on the expected temperature curve i The point POINTe_p-1 which is less than the set threshold value and the pth temperature difference X on the expected temperature curve i Between the points POINTe_p that are less than the set threshold, there is the qth temperature difference X on the expected temperature curve. i If the number of points not less than the set threshold is greater than TS / T, the p-1th temperature difference X on the expected temperature curve is i The temperature difference X between the point POINTe_p-1 which is less than the set threshold and the pth temperature on the expected temperature curve i Points POINTe_p that are smaller than the set threshold are determined as trend change points; Among them, T S Indicates the execution time of the heating subprocess; T indicates the set sampling period; S8: When the number of the trend change points is greater than TS / T, determine the area between two adjacent trend change points as the adjustment interval of the PID controller; and adjust the PID controller parameters based on the adjustment interval of the PID controller to obtain the adjusted PID controller parameters of the adjustment interval of the PID controller; execute S9; The PID control parameters include integral gain, differential gain and proportional gain; Otherwise, when the number of the trend change points is not greater than TS / T, the PID controller parameters at this time are used as the final PID controller parameters, and S10 is executed; Among them, T S represents the execution time of the heating subprocess, and T represents the sampling period; S9: Based on the adjusted PID controller parameters in the adjustment interval of the PID controller, repeatedly execute S3-S8 until the number of trend change points is no more than TS / T, and use the adjusted PID controller parameters in the adjustment interval of the PID controller at this time as the final PID controller parameters; The method of obtaining the adjusted PID controller parameters of the adjustment interval of the PID controller is as follows: S801: Set the initial integral gain and differential gain to zero; and initialize the proportional gain; S802: increasing the initialized proportional gain according to the set step size to obtain an adjusted proportional gain, so as to obtain an adjusted PID controller based on the adjusted proportional gain and the initial integral gain and differential gain; S803: According to the actual temperature at the start time of the adjustment interval of the PID controller, the target temperature at the end time of the adjustment interval of the PID controller, and the adjusted PID controller, obtaining the actual temperature output by the adjusted PID controller; S804: When the difference between the actual temperature output by the adjusted PID controller and the expected temperature meets the stable oscillation condition, the adjusted proportional gain at this time is recorded as the critical proportional gain Kpu; execute S805; Otherwise, based on the adjusted proportional gain, S802-S803 are repeatedly executed; S805: Obtaining adjusted PID control parameters according to the critical proportional gain Kpu; S10: According to the last PID controller parameters, the last PID controller is obtained to heat the semiconductor heating plate according to the last PID controller, the current temperature of the heating plate and the heating target temperature, so as to control the temperature rise rate of the semiconductor device heating plate.

2. A method for controlling the temperature rise rate of a semiconductor device heating plate according to claim 1, characterized in that: The total number of the heating sub-processes is obtained as follows: Where: N S Represents the total number of heating sub-processes; T e Indicates the heating target temperature of the semiconductor device; T c Indicates the current temperature of the system; T S Represents the execution time of the heating subprocess; V t Indicates the desire to control the rate of heating.

3. A method for controlling the temperature rise rate of a semiconductor device heating plate according to claim 1, characterized in that: The calculation formula of the target temperature of the heating sub-process is as follows: Tm ns =Tc ns +ΔT ns Where: Tm ns Indicates the target temperature of the nsth heating sub-process; ns indicates the index number of the heating sub-process, ns = 1, ..., NS; NS indicates the total number of heating sub-processes; Tc ns represents the starting temperature of the nsth heating subprocess; ΔT ns represents the temperature increment of the nsth heating subprocess; T e Indicates the heating target temperature of the semiconductor device.

4. A method for controlling the temperature rise rate of a semiconductor device heating plate according to claim 1, characterized in that: The formula used to obtain the adjusted PID control parameters is as follows: Kp'=0.6Kpu Ki'=2Kp / Tu Kd'=Kp*Tu / 8 in, Kpu represents the critical proportional gain; Kp represents the proportional gain; Tu represents the stable oscillation cycle time; Ki' represents the adjusted integral gain, Kd' represents the adjusted differential gain, and Kp' represents the adjusted proportional gain.

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