Semiconductor furnace tube temperature compensation method

Abstract

The invention provides a temperature compensation method for wafers in a semiconductor furnace tube. The temperature compensation method comprises the following steps: S1, acquiring physical parameters of the semiconductor furnace tube simultaneously comprising m wafers and n temperature zones so as to construct a temperature field simulation model; wherein each temperature area is an area where each heater on the side wall of the semiconductor furnace tube is located; s2, inputting a preset process temperature curve as a reference temperature of each temperature zone into the temperature field simulation model, and executing multiple rounds of iterative operation by using an optimization algorithm based on a preset optimization range of each temperature zone and a first preset termination condition to generate an optimized temperature of each temperature zone; and S3, performing temperature compensation on each temperature zone based on the n groups of optimized temperatures. The method at least solves the problems that the temperature compensation amount of each heater in the temperature compensation value measured by the existing experimental method is a fixed value, the actual temperature fluctuation condition cannot be adapted, and the existing fixed compensation is not matched when the number of wafers is changed or a process temperature curve is replaced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor equipment control, and particularly to a method for compensating the temperature of a semiconductor furnace tube. Background Art

[0002] Semiconductor furnace tube equipment plays a crucial role in the process of manufacturing semiconductor wafers. To meet specific process requirements, the semiconductor furnace tube must be able to accurately transfer a predetermined process temperature curve to the surface of the wafer. To enable the surface of the wafer to reach the required process temperature, the current furnace tube equipment uses thermocouples (TCs) installed on the cavity wall and a proportional-integral-derivative (PID) control algorithm to adjust the temperature of the heater. In addition, during the actual installation and testing phase of the equipment, a thermocouple wafer is used for temperature measurement, and a temperature compensation value is added to the temperature control system manually. However, since the thermocouples are installed on the inner wall of the furnace tube rather than in direct contact with the surface of the wafer, there will always be a temperature difference between the surface of the wafer and the set process temperature when only using the PID control algorithm combined with the manual fixed-value compensation method, resulting in the inability to fully reach the expected temperature.

[0003] It should be noted that the above introduction of the technical background is only for the convenience of clearly and completely explaining the technical solution of the present application and facilitating the understanding of those skilled in the art. It cannot be considered that the above technical solutions are well-known to those skilled in the art just because these solutions are described in the background art part of the present application. Summary of the Invention

[0004] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a method for compensating the temperature of a semiconductor furnace tube, which is used to solve the problem that the surface of the wafer in the prior art cannot accurately reach the required process temperature.

[0005] To achieve the above purpose and other related purposes, the present invention provides a method for compensating the temperature of a semiconductor furnace tube, including:

[0006] Step S1, obtaining the physical parameters of a semiconductor furnace tube including m wafers and n temperature zones simultaneously to construct a temperature field simulation model; wherein, each temperature zone is the area where each heater on the side wall of the semiconductor furnace tube is located; both m and n are integers greater than or equal to 1;

[0007] Step S2, respectively inputting a preset process temperature curve as the reference temperature of each temperature zone into the temperature field simulation model, and performing multiple rounds of iterative operations based on the preset optimization range of each temperature zone and the first preset termination condition to generate the optimized temperature of each temperature zone;

[0008] Step S3, performing temperature compensation on each temperature zone based on n groups of optimized temperatures.

[0009] Optionally, in step S1, constructing the temperature field simulation model includes:

[0010] After obtaining the physical parameters, construct the thermophysical model inside the semiconductor furnace tube based on the heat transfer equation and the fluid mechanics equation;

[0011] Based on the thermophysical model, establish a numerical model, and preset the boundary conditions of each physical parameter and input them into the numerical model to obtain the temperature field simulation model.

[0012] Optionally, the heat transfer equation includes at least one of the heat conduction equation, the heat convection equation, the heat radiation equation, and the chemical heat reaction equation; the fluid mechanics equation includes at least one of the continuity equation, the Navier-Stokes equation, the energy equation, and the Bernoulli equation.

[0013] Optionally, the physical parameters include the semiconductor furnace tube parameters, the wafer parameters, and the fluid parameters; the semiconductor furnace tube parameters include the furnace tube material property parameters, the furnace tube geometric parameters, and the distribution parameters of each temperature zone; the wafer parameters include the wafer material property parameters and the geometric parameters of the wafer; the fluid parameters include the fluid medium property parameters, the flow characteristic parameters, and the fluid thermodynamics parameters.

[0014] Optionally, the distribution parameters of each temperature zone include the position parameters of each temperature zone relative to the furnace tube and the coupling relationship between each temperature zone.

[0015] Optionally, in step S2, numerically solve the temperature field simulation model based on the finite volume method.

[0016] Optionally, in step S2, perform an iterative operation based on at least one optimization algorithm among the stochastic optimization algorithm and the gradient optimization algorithm.

[0017] Optionally, the iterative operation includes a stochastic optimization algorithm or a gradient optimization algorithm.

[0018] Optionally, when the first preset termination condition reaches a predetermined number of iterations or satisfies the objective function, stop;

[0019] The objective function includes the wafer temperature deviation function and the wafer temperature uniformity function; the wafer temperature deviation function includes the temperature differences between the temperatures in each temperature zone and the temperature of the preset process temperature curve; the wafer temperature uniformity function includes the temperature differences between the wafers in each temperature zone;

[0020] The iterative operation is performed until both the wafer temperature deviation function and the wafer temperature uniformity function satisfy the preset values, then stop the iteration and output the temperature values of the corresponding heaters as the optimized temperature values of each temperature zone.

[0021] Optionally, the semiconductor furnace tube temperature compensation method further includes a correction operation on the temperature field simulation model, including obtaining the actual wafer temperature, using the actual wafer temperature as the optimization target, inputting the boundary conditions and material parameters corresponding to the actual wafer temperature into the temperature field simulation model, and performing multiple rounds of iterative operations based on the preset optimization range of each parameter of the temperature field simulation model and the second preset termination condition to correct the temperature field simulation model, and outputting the corrected temperature field simulation model.

[0022] As described above, the semiconductor furnace tube temperature compensation method of the present invention has the following beneficial effects:

[0023] 1. The present invention models the temperature field simulation model of the semiconductor furnace tube, and then performs temperature optimization through this temperature field simulation model to obtain the optimized heater temperature value; calculates the temperature compensation function of each zone heater using this optimized temperature value and inputs it to the temperature compensation window of each zone of the machine for compensation, which can at least solve the problems that the temperature compensation values of each zone obtained by the traditional experimental method are fixed values and cannot adapt to the actual temperature fluctuations and changes in the number of wafers, or when the process temperature curve is changed, the existing fixed compensation is mismatched, and the problem of mismatched wafer surface temperature caused by the limited detection position of the thermocouple.

[0024] 2. The present invention takes into account including the geometric parameters of the wafer in the modeling process of the temperature field simulation model, can better simulate the simulation model of the semiconductor furnace tube under different numbers of wafers, and ensure the temperature uniformity of each wafer.

[0025] 3. The present invention takes into account temperature compensation for different zones divided based on the heater respectively to better simulate the actual compensation change and ensure the temperature uniformity of each wafer close to the preset process temperature curve.

[0026] 4. The method of the present invention is simple and easy to operate. When the simulation model is accurate enough, all operations and calculations can be completed only with a general-performance server, and it is widely applicable to the field of semiconductor equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It shows a schematic structural diagram of a semiconductor furnace tube.

[0028] Figure 2 It shows a schematic circuit diagram for furnace tube temperature control and compensation based on a thermocouple and a PID algorithm.

[0029] Figure 3 It shows Figure 2 The flowchart of adding furnace tube temperature control and temperature compensation.

[0030] Figure 4It shows a step diagram of the semiconductor furnace tube temperature compensation method of the present invention.

[0031] Figure 5 It shows a flowchart of the semiconductor furnace tube temperature compensation method of the present invention.

[0032] Figure 6 It shows a waveform diagram of different preset process temperature curves provided by the present invention.

[0033] Figure 7 It shows a system flowchart of the semiconductor furnace tube temperature compensation method of the present invention.

[0034] Figure 8 It shows a step diagram of the experimental verification of the present invention.

[0035] Figure 9 It shows a system flowchart of the operation for correcting the temperature field simulation model of the present invention.

[0036] Description of component labels

[0037] 1 Semiconductor furnace tube

[0038] 10 Wafer

[0039] 11 Furnace tube body

[0040] 12 Furnace tube cavity

[0041] 13 Boat

[0042] 14 Thermocouple

[0043] 15 Heater

[0044] 16 Temperature control circuit Detailed implementation manners

[0045] The following illustrates the implementation manners of the present invention through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0046] Please refer to Figures 1 to 9 . It should be noted that the diagrams provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0047] Comparative example

[0048] As Figure 1 shown, a semiconductor furnace tube 1 is provided, which includes a plurality of wafers 10, a furnace tube body 11, and a furnace tube cavity 12. Among them, there is a cavity inside the furnace tube body 11 to form the furnace tube cavity 12. A plurality of wafers 10 are placed inside the furnace tube cavity 12, and fluid (gas) also fills the space in between.

[0049] Specifically, the semiconductor furnace tube 1 further includes a boat 13, a plurality of thermocouples 14, and a plurality of heaters 15. Among them, the boat 13 is used to carry a number of wafers 10. A plurality of thermocouples arranged on the side wall of the furnace tube body 1 are used to detect the temperature inside the furnace in real time. A plurality of heaters 15 arranged on the side wall of the furnace tube body 1 are used for heating. The semiconductor furnace tube 1 further includes a temperature control circuit 16 (as Figure 2 shown), which is used to regulate the temperature of a plurality of heaters 15 and add temperature compensation.

[0050] As Figure 2 shown, this comparative example provides a method for processing wafers 10 in a semiconductor furnace tube 1 by cooperating a PID algorithm with fixed temperature compensation. Among them, the PID (Proportional-Integral-Derivative) algorithm corresponding to each heater is a feedback control algorithm widely used in industrial control systems. It adjusts the control input by calculating the error (i.e., the difference between the expected value and the actual value) to achieve the control target. The semiconductor furnace tube 1 uses the PID algorithm for temperature control and additionally adds a fixed temperature for compensation. In addition to the fact that the thermocouple 14 does not detect the temperature on the surface of the wafer 10, no matter how excellent the performance of the PID algorithm is, it can only make the temperature at the detection position of the thermocouple reach the required value, rather than the wafer surface. In addition, since the PID algorithm actually pre-sets an experimental group and obtains a fixed temperature compensation value by collecting the temperature values of the experimental group, when the wafers enter the actual semiconductor process preparation process, the actual conditions and the experimental group conditions are often different. In theory, different values should be compensated, but the existing method can only compensate the same value based on the preset compensation value, that is, the temperature difference compensation amount in each temperature zone is a fixed value, and it cannot meet the temperature difference compensation amount in each stage. At the same time, if the process temperature curve is changed, it is necessary to re-do the experimental group to determine the compensation value, which is not easy to achieve in actual industrial applications.

[0051] In addition, due to the nonlinearity of the heating process and the coupling effect between multiple temperature zones, even if it is assumed that the thermocouple 14 can be arranged on the surface of the wafer 10 for temperature detection, its compensation value does not conform to the actual situation. For example, if the number of wafers in the experimental group is 100, then when the actual number of wafers reaches 200, the fixed temperature compensation makes it more difficult to accurately control the wafer surface temperature. When the number of wafers changes, there will be a situation where the longitudinal temperature distribution is uneven, which cannot be solved by the traditional fixed temperature compensation method.

[0052] Embodiment

[0053] To solve the above problems, this embodiment provides a new semiconductor furnace tube temperature compensation method. By building a temperature field simulation model for the semiconductor furnace tube, and then combining this temperature field simulation model with an optimization algorithm to optimize the heater temperature, so as to obtain an optimized temperature value and calculate a new compensation function; inputting the temperature value of this temperature compensation function to each heater for compensation can at least solve the problems in the traditional method where the temperature compensation amount of each heater is a fixed value and cannot adapt to the actual temperature fluctuations, changes in the number of wafers, or when the process temperature curve is changed, and the existing fixed compensation is mismatched, as well as the problem of mismatch between the temperature detection position of the thermocouple and the temperature position on the wafer surface.

[0054] As Figure 4 shown, this embodiment provides a method for compensating the temperature of wafers in a semiconductor furnace tube, which is used to compensate the temperature of multiple wafers in the semiconductor furnace tube, and includes:

[0055] Step S1: Obtain the physical parameters of a semiconductor furnace tube that simultaneously includes m wafers and n temperature zones to build a temperature field simulation model; where each temperature zone is the area where each heater on the side wall of the semiconductor furnace tube is located; both m and n are integers greater than or equal to 1.

[0056] Specifically, in this embodiment, the semiconductor furnace tube includes but is not limited to oxidation furnace tubes, diffusion furnace tubes, and annealing furnace tubes. Any furnace tube that exposes wafers to a high-temperature environment to achieve various heat treatment purposes is within the protection scope of this embodiment. In addition, the semiconductor furnace tube can be set to be vertical or horizontal, and is not limited by this embodiment.

[0057] Specifically, in step S1, building the temperature field simulation model includes:

[0058] S11: After obtaining the physical parameters, build a thermal physical model inside the semiconductor furnace tube based on the heat transfer equation and the fluid mechanics equation.

[0059] As an example, the physical parameters include semiconductor furnace tube parameters, wafer parameters, and fluid parameters.

[0060] As a further example, the semiconductor furnace tube parameters include furnace tube material property parameters, furnace tube geometric parameters, and distribution parameters of each temperature zone.

[0061] In this embodiment, the furnace tube material property parameters include the material property parameters of the inner wall of the furnace tube, such as material properties such as viscosity and chemical properties; the furnace tube geometric parameters include the geometric shape of the furnace tube, object size, and structural characteristics.

[0062] In this embodiment, the distribution parameters of each temperature zone include the position parameters of each temperature zone relative to the furnace tube and the coupling relationship between each temperature zone.

[0063] As a further example, the wafer parameters include wafer material property parameters and geometric parameters of the wafer.

[0064] In this embodiment, the geometric parameters of the wafer include the number of wafers and the arrangement relationship of each wafer; in another embodiment, in order to further ensure the accuracy of modeling, the geometric parameters of the wafer also include the size characteristics and shape characteristics of the wafer.

[0065] As a further example, the fluid parameters include fluid medium property parameters, flow characteristic parameters, and fluid thermodynamics parameters.

[0066] In this embodiment, the flow characteristic parameters include fluid pressure, fluid flow rate, and fluid velocity; the fluid thermodynamics parameters include temperature, heat capacity, and density.

[0067] It should be noted that, in fact, as long as the method of this embodiment ensures that the physical parameters including the number of wafers are taken into consideration and a corresponding temperature field simulation model is constructed through heat transfer equations and fluid mechanics equations, the accuracy of the final compensation result is better than that of the temperature compensation of the comparative example. Therefore, other physical parameters are considered as factors for further improving the accuracy on this basis. For example, in this embodiment, the physical parameters may also include the physical structure characteristics of the susceptor in the furnace tube, and taking it into consideration to construct the temperature field simulation model.

[0068] As an example, the heat transfer equations include at least one of the heat conduction equation, the heat convection equation, the heat radiation equation, and the chemical heat reaction equation.

[0069] In this embodiment, during the wafer manufacturing process, the temperature control of the furnace tube process involves various heat transfer and chemical reaction equations. In the furnace tube process, the heat conduction equation describes the process of heat transfer from the heater in the furnace tube to the wafer through contact; the heat convection equation describes the process of heat reaching the wafer through fluid convection (such as gas) in the furnace tube; the heat radiation equation describes the process of heat reaching the wafer through electromagnetic waves in the furnace tube. The chemical heat reaction equation describes the heat generation and heat release process during the chemical reaction in the furnace tube; where the chemical reaction includes but is not limited to the diffusion of dopants and various chemical reactions during the formation of the oxide layer. Therefore, the heat transfer equations in the furnace tube need to obtain at least the material properties in the furnace tube (wafer material property parameters, fluid medium property parameters), the boundary conditions in the industrial process (such as flow characteristic parameters, fluid thermodynamics parameters), and the geometric parameters in the furnace tube and cooperate with the fluid mechanics equations to construct a thermophysical model.

[0070] It should be noted that in the actual modeling process, at least one corresponding equation of the above four heat exchange methods needs to be considered, and it is preferable to simultaneously use the equations corresponding to the four heat exchange methods to generate a temperature field simulation model. Among them, when generating a temperature field simulation model based on the equations corresponding to the four heat exchange methods, the participation degrees of the equations corresponding to each heat exchange method in constructing the temperature field simulation model can be set differently or the same, as long as the final temperature field simulation model can reflect the heat exchange law of the furnace tube objective world, the settings are within the protection scope of this embodiment.

[0071] As an example, the fluid mechanics equations include at least one of the continuity equation, the Navier-Stokes equation, the energy equation, and the Bernoulli equation.

[0072] In this embodiment, the continuity equation describes that the flow of gas in the furnace tube is continuous; the Navier-Stokes equation describes the prediction of the flow pattern and velocity distribution of gas in the furnace tube; the energy equation is used to describe the temperature distribution and heat transfer process of gas in the furnace tube; the Bernoulli equation can be used to predict the pressure and velocity distribution of gas in the furnace tube. Therefore, the fluid mechanics equations in the furnace tube need to obtain at least the fluid medium property parameters, flow characteristic parameters, fluid thermodynamics parameters, distribution parameters of each temperature zone, furnace tube material property parameters, furnace tube geometric parameters, etc., and cooperate with the heat transfer equations to jointly construct a thermal physical model.

[0073] It should be noted that in the actual modeling process, it is preferable to simultaneously use the equations corresponding to the above four methods to generate a temperature field simulation model. Among them, when generating a temperature field simulation model based on the equations corresponding to the four methods, the participation degrees of the equations corresponding to each method in constructing the temperature field simulation model can be set differently or the same, as long as the final temperature field simulation model can reflect the actual fluid mechanics law of the furnace tube, the settings are within the protection scope of this embodiment.

[0074] It should be further noted that in this embodiment, fluid mechanics and heat transfer are simultaneously considered to construct a temperature field simulation model of the furnace tube, and then at least the relationship between the number of wafers in the geometric parameters of the wafer and each heater (temperature zone) is related, which is convenient for subsequent compensation of the parameters on the surface of each wafer. In fact, any temperature field simulation model that can construct the relationship between each wafer and each heater is within the protection scope of this embodiment.

[0075] S12. Establish a numerical model based on the thermal physical model, and preset the boundary conditions of each physical parameter and input them into the numerical model to obtain a temperature field simulation model.

[0076] In this embodiment, obtaining preset physical parameters includes, but is not limited to, parameters such as temperature, pressure, and flow rate as boundary conditions to construct a final temperature field simulation model. Among them, each preset physical parameter is set based on actual industrial nodes to facilitate subsequent optimization operations under boundary conditions.

[0077] As Figure 4 , Figure 5 and Figure 7 shown, in step S2, the preset process temperature curves are respectively input into the temperature field simulation model as the reference temperatures for each temperature zone, and a multi-round iterative optimization operation is performed using an optimization algorithm based on the preset optimization range and the first preset termination condition for each temperature zone to generate the optimized temperature for each temperature zone.

[0078] Specifically, in this embodiment, the preset process temperature curve is set based on the process curve required by the actual process node and can be set by the staff. Among them, different process temperature curves are set according to different semiconductor heat treatment processes such as oxidation, diffusion, and annealing applicable to semiconductor furnace tubes, as Figure 6 shown. This preset process temperature zone curve may include multiple stages, such as a heating stage, a holding stage, and a cooling stage. The preset process temperature curves are respectively used as the reference temperatures for each temperature zone, and the process temperatures required for each stage are used as the reference temperatures and input into the temperature field simulation model.

[0079] Specifically, in step S2, the temperature field simulation model is numerically solved based on the finite volume method, and an optimization operation is simultaneously performed based on the optimization algorithm.

[0080] Specifically, in step S2, an iterative operation is performed based on at least one of a stochastic optimization algorithm and a gradient optimization algorithm.

[0081] As an example, the iterative operation includes a stochastic optimization algorithm and a gradient optimization algorithm. Specifically, the iterative operation includes, but is not limited to, stochastic optimization algorithms such as the AMOP algorithm and the particle swarm optimization (PSO) algorithm, and gradient optimization algorithms such as the Levenberg - Marquardt algorithm and the Powell's Dog Leg algorithm. In this embodiment, the AMOP algorithm is selected to perform the iterative operation. Among them, the AMOP algorithm solves the inverse problem through multi - objective optimization to obtain the optimized heater temperature for each temperature zone.

[0082] It should be noted that other arbitrary algorithms can actually be adopted for the iterative operation, and it is not limited to this embodiment.

[0083] Specifically, the preset optimization range can be set based on the temperature range of the process temperature curve, such as set to 23 degrees Celsius to 1500 degrees Celsius; it can also be directly set in a certain temperature range based on the pre-test results. It is required that the subsequent iterative process performs optimization within this preset optimization range. It should be noted that the optimization space must include the optimal temperature value, and the smaller the space range, the faster the iterative convergence speed. At the same time, using the preset process temperature curve as the optimization starting point, a response surface model is constructed, and finally iterative optimization is performed based on this response surface model to obtain the optimized temperature of different temperature zones.

[0084] Specifically, the first preset termination condition is to stop when reaching a predetermined number of iterations or when the objective function is satisfied.

[0085] As an example, the objective function includes a wafer temperature deviation function and a wafer temperature uniformity function.

[0086] As a further example, the wafer temperature deviation function includes the temperature difference between the temperature in each temperature zone and the temperature of the preset process temperature curve respectively; the wafer temperature uniformity function includes the temperature difference between the wafers in each temperature zone. The iterative operation is executed until both the wafer temperature deviation function and the wafer temperature uniformity function satisfy the preset values, then the iteration stops and the corresponding temperature value is output as the optimized temperature value of each temperature zone.

[0087] In this embodiment, the wafer temperature deviation function satisfies:

[0088]

[0089] where n is the number of temperature monitoring points sampled in the temperature field simulation model; is the temperature of the sampling point in the temperature field simulation model; T Ideal is the reference temperature corresponding to the preset process temperature curve. In this embodiment, n is taken as 10. By constraining the relationship between the temperature field simulation model and the reference temperature, it is ensured that the finally optimized temperature satisfies the reference temperature.

[0090] In this embodiment, the wafer temperature uniformity function satisfies:

[0091] F ob2 =|T CFD_max -T CFD_min | (2);

[0092] where, T CFD_max is the maximum temperature in the temperature field simulation model of each wafer, T CFD_min is the minimum temperature in the temperature field simulation model of each wafer. By constraining the difference between the maximum and minimum values of the temperature of each wafer, it is beneficial to ensure the uniformity between the wafers (if the wafers are arranged longitudinally, it is the longitudinal uniformity; if the wafers are arranged horizontally, it is the horizontal uniformity).

[0093] The above formulas (1) and (2) both need to meet their respective convergence conditions: F ob1 / n ≤ Tr and F ob2 ≤ Tr; where Tr needs to ensure meeting the process production standards, such as 95% - 105% of each reference temperature.

[0094] It should be noted that after being constrained by the objective function, it can simultaneously achieve that each wafer meets the preset process temperature curve and ensure the temperature uniformity between the temperatures of each wafer.

[0095] It should be further noted that other preset termination conditions can also be set to end the optimization, not limited to the way provided in this embodiment.

[0096] Step S3: Perform temperature compensation on each temperature zone based on the n groups of optimized temperatures.

[0097] The n groups of optimized temperatures are obtained by iterative calculation of the optimization algorithm, and the values of each group of optimized temperatures can be unequal; in this embodiment, after multiple rounds of iteration, the optimized temperatures corresponding to multiple temperature zones will be output, and these optimized temperatures are different from each other. By performing corresponding heating operations on each heater through these optimized temperatures, the corresponding temperatures of each temperature zone can be achieved to realize temperature compensation.

[0098] It should be noted that since the preset temperature curve actually changes with the time stage, the finally obtained optimized temperature is actually a time - temperature function that also changes with the time stage. When actually setting the temperature of each heater, the time - temperature function of the optimized temperature can be directly input, or the values (derivatives) of the time - temperature function at each point can be correspondingly input. As long as the method of setting the heater temperature based on the optimized temperature is within the protection scope of this embodiment.

[0099] It should be further noted that during the process of wafer preparation, as long as the preset temperature process curve, boundary conditions such as pressure, gas, flow rate, and parameters such as the number of wafers are set, the temperature values of the heaters in each temperature zone that enable each wafer to meet the preset temperature process curve can be obtained. Due to the method of this embodiment, the relationship between the wafer and the heater, especially the relationship between the number of wafers and the heater, is constructed into the temperature field simulation model, which can ensure that corresponding optimized temperatures can be obtained for any number of wafers and compensated through the heaters.

[0100] Assume that 5 temperature zones are set based on the temperature of the heater in this embodiment. Compare the compensation results of each temperature zone in this embodiment with those of the comparative example, and the following table is obtained:

[0101]

[0102] Among them, the compensation value (Theater) for each temperature zone in the comparative example is obtained by first measuring the temperature of the thermocouple on the inner wall of the furnace tube (Ttc) and then adding the compensation value (ΔT) obtained based on a large number of measurements. When the process temperature curve changes (between Process 1 and Process 2), since the temperature of the thermocouple (Ttc) does not change, the compensation value usually does not change, unless a new compensation value is obtained through a large number of experimental measurements, which is difficult to achieve in industrial production. In contrast, in this embodiment, after constructing the temperature field simulation model, different compensation functions (Δ t1 ) can be obtained as different optimization objectives based on different process temperature curves. These compensation functions are quantities that change with time and also keep consistent with the change of the process temperature curve; they can adapt to different process temperature curves for dynamic compensation without the need to collect a large amount of data again to set new compensation values. At the same time, in this embodiment, since the self-adaptive compensation temperatures in different temperature zones are different and the connection between different temperature zones is constructed, the temperature uniformity of each wafer can be guaranteed; similarly, the compensation function (Δ t1 ) in this embodiment is constructed based on the heat exchange relationship between the semiconductor furnace tube and the wafer, so the actual compensation effect is more accurate.

[0103] Specifically, this embodiment also provides an operation for correcting the temperature field simulation model, as shown in Figure 8 and Figure 9 , including:

[0104] Step A: Obtain the actual wafer temperature (in this embodiment, it is obtained by testing the thermocouple pre-buried on the wafer surface. In actual production, the thermocouple for measuring the temperature of the furnace tube equipment is set on the inner wall of the furnace tube).

[0105] Step B: Take the actual wafer temperature as the optimization objective, input the boundary conditions and material parameters corresponding to the actual wafer temperature into the temperature field simulation model (that is, take the model parameters of the temperature field simulation model as the optimization variables), and perform multiple rounds of iterative operations based on the preset optimization range of each parameter of the temperature field simulation model and the second preset termination condition to correct the temperature field simulation model, and output the corrected temperature field simulation model.

[0106] Among them, in this embodiment, the iterative correction of the model parameters of the temperature field simulation model is continued using the aforementioned optimization method until the second preset stop condition is met, and then the corrected temperature field simulation model is output. Among them, it is equivalent to taking the temperature field simulation model as the correction variable and using the previous optimization method for adjustment to make it meet the actual simulation modeling requirements. The specific optimization method can be set with reference to the previous text and will not be elaborated here one by one.

[0107] In this embodiment, a machine tool experiment verification can be set to be executed after steps S1 and S2 to verify whether the wafer after optimized temperature compensation meets the preset process temperature curve. If it meets, step S3 is directly executed; if it fails to meet, it is considered that the construction error value of the temperature field simulation model is too large, and the temperature field simulation model needs to be adjusted. In this embodiment, a correction operation is directly set after step S2, without performing an experiment verification on the machine tool.

[0108] It should be noted that it is not necessary to execute the model correction step every time the temperature compensation function is calculated using the method of this embodiment. After performing a limited number of corrections only at the initial stage of building the simulation model, a high-precision simulation model can be obtained.

[0109] It should be further noted that in this embodiment, the second preset stop condition is set based on requirements. Similarly, the number of iterations can be set, or it can be required to meet the constraint function. The setting of this constraint function can be based on the principle described above to constrain the temperature parameters, or other parameters can be adjusted for constraint setting, and it is not limited to this embodiment. As long as it is ensured that during the correction operation, the actual wafer temperature is used as the optimization direction to correct the temperature field simulation model, so as to ensure that the simulation effect of the temperature field simulation model is close to the settings of the actual machine tool, it is within the protection scope of this embodiment.

[0110] In summary, the present invention provides a method for compensating the temperature of a wafer in a semiconductor furnace tube, including: S1, obtaining the physical parameters of a semiconductor furnace tube including m wafers and n temperature zones simultaneously to build a temperature field simulation model; where each temperature zone is the area where each heater on the side wall of the semiconductor furnace tube is located; S2, inputting the preset process temperature curve as the reference temperature of each temperature zone into the temperature field simulation model respectively, and performing multiple rounds of iterative operations based on the preset optimization range of each temperature zone and the first preset termination condition to generate the optimized temperature of each temperature zone; S3, performing temperature compensation on each temperature zone based on n groups of optimized temperatures. The present invention at least solves the problems that in the process of measuring the temperature compensation value by the traditional experimental method, the temperature compensation amount of each heater is a fixed value and cannot adapt to the actual temperature fluctuation situation, the change of the number of wafers, or the replacement of the process temperature curve, resulting in the mismatch of the existing fixed compensation, as well as the problem of the mismatch of the wafer surface temperature caused by thermocouple detection. Therefore, the present invention effectively overcomes various disadvantages in the prior art and has high industrial utilization value.

[0111] The above embodiments only illustratively explain the principles and effects of the present invention, rather than limiting the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A method for compensating wafer temperature in a semiconductor furnace tube, characterized in that: The method for compensating the temperature of a wafer in a semiconductor furnace tube comprises: Step S1, obtaining physical parameters of a semiconductor furnace tube including m wafers and n temperature zones to construct a temperature field simulation model; wherein each temperature zone is an area where each heater on the side wall of the semiconductor furnace tube is located; m and n are both integers greater than or equal to 1; Step S2, inputting the preset process temperature curve as the reference temperature of each temperature zone into the temperature field simulation model, and performing multiple rounds of iterative operations based on the preset optimization range of each temperature zone and the first preset termination condition to generate the optimized temperature of each temperature zone; Step S3: performing temperature compensation on each temperature zone based on the optimized temperature of the n groups.

2. The semiconductor furnace tube temperature compensation method according to claim 1, characterized in that: In step S1, constructing a temperature field simulation model includes: After obtaining the physical parameters, a thermal physical model of the interior of the semiconductor furnace tube is constructed based on a heat transfer equation and a fluid mechanics equation; A numerical model is established based on the thermal physics model, and boundary conditions of various physical parameters are preset and input into the numerical model to obtain the temperature field simulation model.

3. The semiconductor furnace tube temperature compensation method according to claim 2, characterized in that: The heat transfer equation includes at least one of the heat conduction equation, the heat convection equation, the heat radiation equation and the chemical heat reaction equation; the fluid mechanics equation includes at least one of the continuity equation, the Navier-Stokes equation, the energy equation and the Bernoulli equation.

4. The semiconductor furnace tube temperature compensation method according to any one of claims 1 to 3, characterized in that: The physical parameters include the semiconductor furnace tube parameters, the wafer parameters and the fluid parameters; the semiconductor furnace tube parameters include furnace tube material property parameters, furnace tube geometric parameters, and distribution parameters of each temperature zone; the wafer parameters include wafer material property parameters and wafer geometric parameters; the fluid parameters include fluid medium property parameters, flow characteristic parameters, and fluid thermodynamic parameters.

5. The semiconductor furnace tube temperature compensation method according to claim 4, characterized in that: The distribution parameters of each temperature zone include the position parameters of each temperature zone relative to the furnace tube and the coupling relationship between the temperature zones.

6. The semiconductor furnace tube temperature compensation method according to claim 1, characterized in that: In step S2, the temperature field simulation model is numerically solved based on the finite volume method.

7. The semiconductor furnace tube temperature compensation method according to claim 1, characterized in that: In step S2, an iterative operation is performed based on at least one optimization algorithm of a random optimization algorithm and a gradient optimization algorithm.

8. The semiconductor furnace tube temperature compensation method according to claim 1, characterized in that: The iterative operation includes a stochastic optimization algorithm or a gradient optimization algorithm.

9. The semiconductor furnace tube temperature compensation method according to claim 1, characterized in that: The first preset termination condition stops when a predetermined number of iterations is reached or an objective function is satisfied; The objective function includes a wafer temperature deviation function and a wafer temperature uniformity function; the wafer temperature deviation function includes the temperature difference between the temperature in each temperature zone and the preset process temperature curve; the wafer temperature uniformity function includes the temperature difference between wafers in each temperature zone; The iterative operation is performed until the wafer temperature deviation function and the wafer temperature uniformity function both meet preset values, then the iteration is stopped and the temperature values ​​of the corresponding heaters are output as the optimized temperature values ​​of each temperature zone.

10. The semiconductor furnace tube temperature compensation method according to claim 1, characterized in that: The semiconductor furnace tube temperature compensation method also includes a correction operation on the temperature field simulation model, including obtaining the actual wafer temperature, and taking the actual wafer temperature as the optimization target, inputting the boundary conditions and material parameters corresponding to the actual wafer temperature into the temperature field simulation model, performing multiple rounds of iterative operations based on the preset optimization range of each parameter of the temperature field simulation model and the second preset termination condition to correct the temperature field simulation model, and outputting the corrected temperature field simulation model.

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