Wafer temperature control device, wafer temperature control method and wafer temperature control program

Abstract

To control a wafer temperature to a target temperature by estimating the wafer temperature with sufficient accuracy in a device controlling the temperature of a wafer by regulating a pressure of a heat transfer gas.SOLUTION: In a wafer temperature control device 100, a wafer W is mounted on a plate 2 of which the temperature is adjusted, and a temperature of the wafer W is controlled by supplying a heat transfer gas between the plate 2 and the wafer W. The wafer temperature control device comprises: a pressure regulator 43 which regulates a pressure of the heat transfer gas; a vicinity temperature sensor 5 which measures a vicinity temperature of the wafer W; a temperature estimation observer 10 which estimates the temperature of the wafer W based on the vicinity temperature measured by the vicinity temperature sensor 5 and a pressure operation amount inputted to the pressure regulator 43 or the pressure regulated by the pressure regulator; and a controller 11 which controls the pressure operation amount based on a preset temperature and the estimation wafer temperature estimated by the temperature estimation observer 10.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a wafer temperature control device, a wafer temperature control method, and a wafer temperature control program. [Background technology]

[0002] Conventionally, in a semiconductor manufacturing process such as a film formation process, a wafer to be processed is placed on a plate such as an electrostatic chuck, and the temperature of the plate such as an electrostatic chuck is adjusted to control the temperature of the wafer to a predetermined target temperature.

[0003] Since the plate on which the wafer is placed is placed in a low-pressure environment such as a vacuum, as shown in Patent Document 1, it has been considered to supply a heat transfer gas such as helium gas between the plate and the wafer in order to promote heat transfer from the temperature-regulated plate to the wafer.

[0004] Here, since the heat transfer coefficient varies depending on the pressure of the heat transfer gas supplied between the plate and the wafer, it is necessary to adjust the pressure of the heat transfer gas.

[0005] However, even if the pressure of the heat transfer gas is adjusted, it is difficult to measure the temperature of the wafer itself placed on the plate due to various technical constraints.

[0006] As disclosed in Patent Document 2, a temperature control device has been devised in which a temperature sensor is provided in the stage to measure the temperature in the vicinity of the wafer, and an observer estimates the temperature of the electronic devices formed on the wafer.

[0007] However, this temperature control device is not designed to supply heat transfer gas between the stage and the wafer, and the observer does not use the pressure of the heat transfer gas as an input variable, making it difficult to estimate the wafer temperature with sufficient accuracy and control the wafer temperature to a constant target temperature. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 4034344 [Patent Document 2] Patent Publication No. 2021-19066 Summary of the Invention [Problem to be solved by the invention]

[0009] Therefore, the present invention has been made to solve the above-mentioned problems, and has an object to estimate the wafer temperature with sufficient accuracy and control the wafer temperature to a target temperature in a device that controls the wafer temperature by adjusting the pressure of a heat transfer gas. [Means for solving the problem]

[0010] That is, the wafer temperature control device of the present invention is a wafer temperature control device in which a wafer is placed on a temperature-adjusted plate and a heat transfer gas is supplied between the plate and the wafer to control the temperature of the wafer, and is characterized in that it comprises a pressure regulator that adjusts the pressure of the heat transfer gas, a nearby temperature sensor that measures the nearby temperature of the wafer, a temperature estimation observer that estimates the temperature of the wafer based on the nearby temperature measured by the nearby temperature sensor and a pressure manipulation amount input to the pressure regulator or a pressure adjusted by the pressure regulator, and a controller that controls the pressure manipulation amount based on the set temperature of the wafer and the estimated wafer temperature estimated by the temperature estimation observer.

[0011] In such a wafer temperature control device, the wafer temperature is estimated using a temperature estimation observer that uses the pressure of the heat transfer gas as an input variable, so that the wafer temperature can be estimated with sufficient accuracy. Also, the pressure manipulated variable input to the pressure regulator that adjusts the pressure of the heat transfer gas is controlled based on the set wafer temperature and the estimated wafer temperature estimated by the temperature estimation observer, so that the wafer temperature can be controlled to the target temperature with high accuracy.

[0012] Although it is possible to control the cooling operation amount input to a cooler for adjusting the temperature of the plate or the heating operation amount input to a heater, fine adjustment of the wafer temperature is difficult. Controlling the pressure operation amount input to a pressure regulator, as in the present invention, makes it easier to fine-tune the wafer temperature.

[0013] Here, the nearby temperature is, for example, the temperature of a member or space within a predetermined distance from the wafer, and includes a temperature for which a temperature model showing the relationship between the wafer temperature and the nearby temperature can be constructed. The nearby temperature also includes the temperature of a member in direct contact with the wafer, the temperature of the space or gas where the interface with the wafer exists, or the temperature of a member that exists across a gap of several μm from the wafer W. Furthermore, the nearby temperature may include the temperature of a member where heat can be conducted or transferred between the wafer and the member by at least one of conduction, convection, and radiation.

[0014] Here, in order to estimate the wafer temperature using a simple system, it is considered that the temperature estimation observer uses a state space model in which the relationship between the wafer temperature and the pressure of the heat transfer gas is linear. However, in an actual environment, there is a nonlinear relationship between the wafer temperature and the pressure of the heat transfer gas, which causes an error between the wafer temperature and the estimated wafer temperature estimated by the temperature estimation observer, making it difficult to accurately control the wafer temperature to the target temperature. In order to suitably solve this problem, it is desirable for the controller to correct the set temperature using a nonlinear relationship between the previously acquired wafer temperature and the pressure of the heat transfer gas, and to control the pressure manipulation variable so as to reduce the temperature deviation between the corrected set temperature and the estimated wafer temperature.

[0015] As a specific embodiment of correcting the set temperature of the wafer using the nonlinear relationship between the previously acquired wafer temperature and the pressure of the heat transfer gas, the controller has a relationship data storage unit that stores nonlinear relationship data indicating the nonlinear relationship between the previously acquired wafer temperature and the pressure of the heat transfer gas, and linear relationship data indicating the linear relationship between the wafer temperature and the pressure of the heat transfer gas used in the state space model of the temperature estimation observer, and a converted pressure that corresponds nonlinearly to the set temperature is calculated from the set temperature and the nonlinear relationship data, and a converted temperature that corresponds linearly to the converted pressure is calculated from the converted pressure and the linear relationship data, and the converted temperature is set as the corrected set temperature.

[0016] In order to improve the estimation accuracy of the estimated wafer temperature by correcting the estimation error of the estimated wafer temperature caused by the deviation of the initial temperature, it is desirable that the temperature estimation observer is configured to include a temperature estimation model which is a linear state space model with the wafer temperature and the nearby temperature as output variables, a nearby temperature output unit which outputs the estimated nearby temperature estimated based on the temperature estimation model, a wafer temperature output unit which outputs the estimated wafer temperature estimated based on the temperature estimation model, and an observer gain, and to feed back into the temperature estimation model a value obtained by multiplying the deviation between the estimated nearby temperature output from the nearby temperature output unit and the nearby temperature measured by the nearby temperature sensor, or a value calculated from the deviation, by the observer gain.

[0017] In addition, in order to improve the estimation accuracy of the estimated wafer temperature by taking into account the nonlinearity of the plate temperature, it is desirable that the temperature estimation observer is configured to include a temperature estimation model which is a linear state space model with the wafer temperature and the nearby temperature as output variables, a nearby temperature output unit which outputs the estimated nearby temperature estimated based on the temperature estimation model, a nearby temperature correction unit which corrects the estimated nearby temperature output from the nearby temperature output unit taking into account the nonlinear characteristics of the plate temperature, a wafer temperature output unit which outputs the estimated wafer temperature estimated based on the temperature estimation model, and an observer gain, and the deviation between the corrected estimated nearby temperature output from the nearby temperature correction unit and the nearby temperature measured by the nearby temperature sensor, or a value calculated from the deviation, multiplied by the observer gain, is fed back into the temperature estimation model.

[0018] In order to simplify the control input and easily maintain the wafer temperature at a constant value, it is conceivable to set the cooling operation amount input to a cooler for adjusting the temperature of the plate or the heating operation amount input to a heater to a constant value. In this case, it is desirable for the temperature estimation observer to include the temperature estimation model according to the temperature of the plate after temperature adjustment.

[0019] In addition, a wafer temperature control method according to the present invention is a wafer temperature control method in which a wafer is placed on a temperature-adjusted plate and a heat transfer gas is supplied between the plate and the wafer to control the temperature of the wafer, the method comprising the steps of: adjusting the pressure of the heat transfer gas using a pressure regulator; measuring the temperature in the vicinity of the wafer using a proximity temperature sensor; estimating the temperature of the wafer using a temperature estimation observer based on the proximity temperature measured by the proximity temperature sensor and a pressure manipulation amount input to the pressure regulator or a pressure adjusted by the pressure regulator; and controlling the pressure manipulation amount based on the set temperature of the wafer and the estimated wafer temperature estimated by the temperature estimation observer.

[0020] Furthermore, the wafer temperature control program of the present invention is a wafer temperature control program used in a wafer temperature control device that has a pressure regulator that adjusts the pressure of the heat transfer gas and a nearby temperature sensor that measures the nearby temperature of the wafer, in which a wafer is placed on a temperature-regulated plate and a heat transfer gas is supplied between the plate and the wafer to control the temperature of the wafer, and is characterized in that the program has a computer equipped with a function as a temperature estimation observer that estimates the temperature of the wafer based on the nearby temperature measured by the nearby temperature sensor and the pressure manipulation amount input to the pressure regulator or the pressure adjusted by the pressure regulator, and a function as a controller that controls the pressure manipulation amount based on the set temperature of the wafer and the estimated wafer temperature estimated by the temperature estimation observer.

[0021] The wafer temperature control program may be distributed electronically, or may be recorded on a program recording medium such as a CD, a DVD, or a flash memory.

[0022] The present invention described above is an embodiment in which the set temperature of the wafer is corrected using a nonlinear relationship between the temperature of the wafer and the pressure of the heat transfer gas, but the set temperature of the wafer may be corrected using a nonlinear relationship between the temperature of the wafer and the temperature of a temperature regulator. That is, the wafer temperature control device according to the present invention includes a temperature regulator that adjusts the temperature of the wafer according to an input temperature manipulation amount, a proximity temperature sensor that measures the temperature in the vicinity of the wafer, a temperature estimation observer that estimates the temperature of the wafer based on the proximity temperature measured by the proximity temperature sensor and the temperature manipulation amount input to the temperature regulator or the temperature of the temperature regulator, and a controller that controls the temperature manipulation amount based on the set temperature of the wafer and the estimated wafer temperature estimated by the temperature estimation observer, the temperature estimation observer uses a state space model in which the relationship between the temperature of the wafer and the temperature of the temperature regulator is linear, and the controller corrects the set temperature using a nonlinear relationship between the temperature of the wafer and the temperature regulator that has been previously acquired, and controls the temperature manipulation amount so that the temperature deviation between the set temperature after the correction and the estimated wafer temperature is small. Effect of the Invention

[0023] As described above, according to the present invention, in a system in which the pressure of the heat transfer gas is adjusted to control the wafer temperature, it is possible to estimate the wafer temperature with sufficient accuracy and control the wafer temperature to a target temperature. [Brief description of the drawings]

[0024] [Figure 1] 1 is a perspective view showing a schematic configuration of a wafer temperature control apparatus according to an embodiment of the present invention; [Diagram 2] 11 is a diagram showing the relationship between the pressure of the heat transfer gas supplied between the wafer and the suction plate and the heat transfer coefficient between the wafer and the suction plate. FIG. [Diagram 3] FIG. 2 is a diagram showing a schematic diagram of a wafer temperature control system in the embodiment. [Figure 4] FIG. 2 is a functional block diagram of a wafer control device in the embodiment. [Diagram 5] 2 is a schematic diagram showing a state space model of the wafer temperature control device in the embodiment. FIG. [Figure 6] 1 is a graph showing a linear relationship (TW_linear) and a non-linear relationship (TW_curve) between the wafer temperature TW and the heat transfer gas pressure PHG. [Figure 7] 4 is a schematic diagram showing a method of correcting the set temperature of the controller in the embodiment. FIG. [Figure 8] 13 shows experimental results of the wafer temperature control apparatus in accordance with the embodiment, where (a) observer control is performed using an uncorrected set temperature TSET, and (b) observer control is performed using a corrected set temperature TSET'. [Figure 9] FIG. 13 is a functional block diagram of a wafer control apparatus according to a modified embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] <One embodiment of the present invention> Hereinafter, an embodiment of a wafer temperature control device according to the present invention will be described with reference to the drawings. In addition, in all of the drawings shown below, for ease of understanding, some parts are omitted or exaggerated as appropriate. The same components are given the same reference numerals and the description thereof is omitted as appropriate.

[0026] The wafer temperature control device 100 of this embodiment is used in a semiconductor manufacturing device that performs a semiconductor manufacturing process such as a film formation process, and is configured to electrostatically chuck the back surface of a wafer W in a vacuum chamber, for example.

[0027] Specifically, the wafer temperature control device 100 includes an adsorption plate 2 on the upper surface of which a wafer W is placed, and a temperature regulator 3 that adjusts the temperature of the adsorption plate 2, as shown in FIG.

[0028] The suction plate 2 constitutes a so-called electrostatic chuck that holds the wafer W by electrostatic suction force. The suction plate 2 in this embodiment is a ceramic plate having a substantially circular shape, and the upper surface thereof serves as an suction surface 2a that suctions the wafer W. An electrostatic electrode (not shown) for generating an electrostatic force between the suction plate 2 and the wafer W is provided inside the suction plate 2.

[0029] The temperature regulator 3 regulates the temperature of the suction plate 2 to a preset temperature, and includes a heater 31 for heating the suction plate 2 and a cooler 32 for cooling the suction plate 2. The temperature regulator 3 may not necessarily include the heater 31.

[0030] The heater 31 is provided inside the suction plate 2, and has a plurality of heater electrodes 31a for heating the suction plate 2. The power supplied to the plurality of heater electrodes 31a is controlled by a heating control unit (not shown) of the control device COM, and each of the heater electrodes 31a is independently controlled according to the amount of heating operation set by the user.

[0031] The cooler 32 is provided in contact with the lower surface of the suction plate 2, and includes a substantially disk-shaped base plate 32a and a cooling passage 32b formed within the base plate 32a.

[0032] The cooling flow passage 32b is formed in a spiral shape in a plan view inside the base plate 32a. An inlet flow passage 32c and an outlet flow passage 32d, which are connected to a cooling source (not shown), such as a chiller, are connected to the cooling flow passage 32b. A control valve 32e for controlling the flow rate of the refrigerant is provided in the flow passage connected to the cooling flow passage 32b, and the valve opening of the control valve 32e is controlled by a valve control unit (not shown) of the control device COM.

[0033] Moreover, the wafer temperature control apparatus 100 of this embodiment includes a gas supply mechanism 4 that supplies a heat transfer gas, such as helium gas or argon gas, between the suction plate 2 and the wafer W.

[0034] The gas supply mechanism 4 supplies a heat transfer gas at a predetermined pressure between the suction surface 2a of the suction plate 2 and the rear surface of the wafer W that is suctioned.

[0035] Specifically, the gas supply mechanism 4 has a gas circulation groove 41 formed on the suction surface 2a of the suction plate 2, a gas supply path 42 for supplying a heat transfer gas to the gas circulation groove 41, and a pressure regulator 43 for adjusting the pressure of the heat transfer gas supplied to the gas circulation groove 41. The heat transfer gas supplied to the gas circulation groove 41 flows from the gas circulation groove 41 into the gap between the suction surface 2a of the suction plate 2 and the back surface of the wafer W being suctioned.

[0036] The gas flow grooves 41 include, for example, a plurality of linear grooves formed radially from the central axis of the suction plate 2, and a plurality of circular grooves formed circularly from the central axis of the suction plate 2. The gas supply passage 42 is formed along the central axis of the suction plate 2, and is connected to a heat transfer gas source (not shown).

[0037] Furthermore, the pressure regulator 43 can adjust the pressure of the heat transfer gas to change the heat transfer rate from the suction plate 2 to the wafer W (the heat transfer coefficient between the wafer W and the suction plate 2). Note that the relationship between the pressure of the heat transfer gas supplied between the wafer W and the suction plate 2 and the heat transfer coefficient between the wafer W and the suction plate 2 is shown in FIG.

[0038] Specifically, the pressure regulator 43 has a pressure sensor and a pressure control valve, and the valve opening degree of the pressure control valve is controlled by the controller 11 of the control device COM.

[0039] The wafer temperature control device 100 also includes a proximity temperature sensor 5 that measures the temperature in the vicinity of the wafer W. The proximity temperature sensor 5 is provided on the rear surface side of the base plate 32a, and measures the temperature of the base plate 32a as the temperature in the vicinity of the wafer W. The proximity temperature sensor 5 in this embodiment is, for example, an infrared temperature sensor. The proximity temperature sensor 5 may also measure the temperature of the suction plate 2 as the temperature in the vicinity of the wafer W.

[0040] <2. Wafer temperature control system> Furthermore, the wafer temperature control apparatus 100 includes a control device COM that controls the operations of at least the temperature regulator 3 and the pressure regulator 43 .

[0041] The control device COM is a so-called computer equipped with a CPU, a memory, an A / D converter, a D / A converter, and various input / output devices. A wafer temperature control program stored in the memory is executed, and various devices cooperate to configure a wafer temperature control system as shown in Figs. 3 and 4.

[0042] First, the outline of the wafer temperature control system of this embodiment will be described with reference to FIG.

[0043] In this embodiment, the estimated wafer temperature T W_est , and the nearby temperature T measured by the nearby temperature sensor 5 P_meas Regardless of the above, a fixed power is supplied to each heater electrode 31a of the heater 31, and the valve opening degree of the control valve 32e of the cooler 32 is controlled to be constant. That is, the heating operation amount and the cooling operation amount are fixed during operation, and the temperature adjustment amount per unit time by the temperature regulator 3 is controlled to be constant.

[0044] In contrast, the pressure regulator 43 is configured to adjust the temperature of the wafer T estimated by the temperature estimation observer 10. W_est , and the nearby temperature T measured by the nearby temperature sensor 5 P_meas The input pressure manipulation amount is successively changed based on the above.

[0045] Specifically, the control device COM uses a temperature estimation observer 10 to estimate the vicinity temperature T P_meas The control device COM estimates the temperature of the wafer W based on the estimated wafer temperature T W_est The estimated wafer temperature T W_est is the set temperature T SET The pressure regulator 43 is controlled to follow the pressure.

[0046] More specifically, as shown in FIG. 3, the control device COM includes a temperature estimation observer 10 for estimating the temperature of the wafer W and a set temperature T SET and the estimated wafer temperature T estimated by the temperature estimation observer 10. W_est and a controller 11 that feedback controls the pressure regulator 43 based on the result of the feedback control.

[0047] <2-1. Temperature estimation observer 10> The temperature estimation observer 10 at least simulates the thermal behavior of the system and estimates the temperature of the wafer W, which cannot be measured directly.

[0048] Specifically, the temperature estimation observer 10 estimates the vicinity temperature T P_meas and the pressure P output by the pressure regulator 43. OUT Based on this, the temperature T of the wafer W is W The estimated wafer temperature T W_est and the nearby temperature T P The estimated nearby temperature T P_est and

[0049] Specifically, the temperature estimation observer 10 estimates the temperature T W and the nearby temperature T P A temperature estimation model 10a is a linear state space model having an output variable, and an estimated wafer temperature T estimated based on the temperature estimation model 10a. W_estand a wafer temperature output unit 10b that outputs an estimated vicinity temperature T P_est and an observer gain 10d.

[0050] The temperature estimation observer 10 then calculates the estimated nearby temperature T P_est and the nearby temperature T measured by the nearby temperature sensor 5. P_meas The deviation from the temperature estimating model 10a is multiplied by an observer gain 10d, and the result is fed back to the temperature estimating model 10a.

[0051] The temperature estimation model 10a is a model of, for example, the heat conduction regarding the suction plate 2 and the wafer W themselves, and the heat transfer between the suction plate 2 and the wafer W.

[0052] This temperature estimation model 10a estimates at least the temperature T W and the pressure of the heat transfer gas P HG An example of the state space model is shown in FIG. 5. The input variable of the temperature estimation model 10a of this embodiment is the pressure P OUT (p in FIG. 5), the amount of heating q by the heater 31 or the amount of cooling by the cooler 32 (the temperature T c ) etc.

[0053] Specifically, the temperature estimation model 10a estimates the pressure P OUT A vector of input variables including the estimated wafer temperature T W_est and the estimated nearby temperature T P_est The output is a state variable vector containing

[0054] The wafer temperature output unit 10b estimates the wafer temperature T W_est and outputs it to the controller 11.

[0055] The neighboring temperature output unit 10c calculates the estimated neighboring temperature T P_est The output estimated nearby temperature T P_est and the nearby temperature T measured by the nearby temperature sensor 5 P_meas The deviation from this is calculated and input to the observer gain 10d.

[0056] <2-2.Controller 11> The controller 11 sets the temperature T SET and the estimated wafer temperature T estimated by the temperature estimation observer 10. W_est Based on and the pressure of the heat transfer gas P HG The pressure regulator 43 controls the pressure regulator 43 to adjust the pressure.

[0057] In the actual environment, as shown in FIG. W and the pressure of the heat transfer gas P HG On the other hand, in the above-mentioned temperature estimation observer 10, the output (temperature T of the wafer W) relative to the pressure manipulation amount is W ) is assumed to be linear, and the temperature T W and the pressure of the heat transfer gas P HG It is assumed that there is a linear relationship between

[0058] For this reason, the controller 11 of this embodiment controls the temperature T of the wafer W acquired in advance as shown in FIG. W and the pressure of the heat transfer gas P HG The set temperature T SET After correcting, the set temperature T SET ' and the estimated wafer temperature T W_est The pressure manipulated variable is controlled so as to reduce the temperature deviation between the pressure manipulated variable and the temperature manipulated variable.

[0059] Specifically, the controller 11 controls the temperature T W and the pressure of the heat transfer gas P HG and the temperature T of the wafer W used in the state space model of the temperature estimation observer 10. Wand the pressure of the heat transfer gas P HG and linear relationship data indicating a linear relationship between the

[0060] Then, the controller 11 calculates the input set temperature T SET From the nonlinear relationship data, the set temperature T SET The equivalent pressure P corresponds nonlinearly to SET The controller 11 also calculates the converted pressure P SET From the linear relationship data, the converted pressure P SET The converted temperature is calculated as the linearly corresponding temperature, and the converted temperature is set to the corrected set temperature T SET '.

[0061] Next, the controller 11 calculates the corrected set temperature T SET ' and the estimated wafer temperature T estimated by the temperature estimation observer 10. W_est The temperature deviation between the temperature vector and the state variable vector is multiplied by a gain K to perform an integral operation. The controller 11 also calculates the deviation between the calculated integral value and a value obtained by multiplying the state variable vector by a predetermined state feedback gain F, and inputs this deviation to the pressure regulator 43 as a pressure manipulation amount.

[0062] Next, in the controller 11, the uncorrected set temperature T SET When observer control is used, and when the corrected set temperature T SET The experimental results when the observer was used are shown in Fig. 8. Fig. 8(a) shows the uncorrected set temperature T SET The results are shown in Fig. 8(b) when the observer control is used. The corrected set temperature T SET This is the result when observer control is performed using the set temperature T SET When using the above, the temperature T of the wafer W W and the wafer temperature T estimated by the temperature estimation observer 10. W_est On the other hand, there is an error in the corrected set temperature T SET When using the temperature T W and the wafer temperature T estimated by the temperature estimation observer 10. W_est The error between the two is decreasing.

[0063] <3. Effects of this embodiment> In this manner, according to the wafer temperature control apparatus 100 of the present embodiment, the pressure P HG The temperature T of the wafer W is calculated using a temperature estimation observer 10 with the following input variables: W Since the temperature of the wafer W is estimated, W The set temperature T of the wafer W can be estimated with sufficient accuracy. SET and the estimated wafer temperature T estimated by the temperature estimation observer 10. W_est Based on and the pressure of the heat transfer gas P HG Since the pressure control amount input to the pressure regulator 43 that adjusts the pressure is controlled, the wafer temperature can be controlled to the target temperature with high precision.

[0064] It is also possible to control the amount of cooling input to the cooler 32 for adjusting the temperature of the suction plate 2 or the amount of heating input to the heater 31. W It is difficult to finely adjust the temperature T of the wafer W, and it is preferable to control the pressure control amount input to the pressure regulator 43 as in this embodiment. W This makes it easier to fine-tune the setting.

[0065] In particular, in this embodiment, the controller 11 controls the temperature T W and the pressure of the heat transfer gas P HG The set temperature T SET After correcting, the set temperature T SET ' and the estimated wafer temperature T W_est The pressure control amount is controlled so as to reduce the temperature deviation from the estimated wafer temperature T W_est The estimation error of the temperature T of the wafer W can be reduced. W can be precisely controlled to the target temperature.

[0066] <4. Other embodiments> As shown in FIG. 9, the temperature estimation observer of the embodiment estimates the estimated neighboring temperature T P_estThe temperature correction unit 10e further includes a neighborhood temperature correction unit 10e that corrects the estimated neighborhood temperature T P_est ' and the nearby temperature T measured by the nearby temperature sensor 5. P Alternatively, a value obtained by multiplying the deviation from the temperature estimation model 10a or a value calculated from the deviation by the observer gain 10d may be fed back into the temperature estimation model 10a.

[0067] In the above embodiment, the temperature of the suction plate 2 is adjusted to be constant, but the wafer temperature control device 100 may be configured to change the temperature of the suction plate 2. In this case, the temperature estimation observer 10 may be configured to include a temperature estimation model 10a corresponding to the temperature of the suction plate 2 whose temperature has been adjusted.

[0068] The temperature estimation observer 10 estimates the estimated nearby temperature T P_est and the nearby temperature T measured by the nearby temperature sensor 5. P The temperature estimation model 10a may be configured to further include an observer integrator that integrates the deviation from the temperature estimating model 10a, and the integral value output from the observer integrator may be multiplied by an observer gain 10d and fed back to the temperature estimation model 10a.

[0069] In this case, the estimated nearby temperature T P_est and the nearby temperature T P It is conceivable to feed back to the temperature estimation model 10a a value obtained by multiplying the deviation from the temperature estimation model 10a by the proportional observer gain, and to feed back to the temperature estimation model 10a a value obtained by multiplying the integral value of the deviation by the integral observer gain. It is also conceivable to feed back to the temperature estimation model 10a only a value obtained by multiplying the integral value of the deviation by the integral observer gain.

[0070] The cooler and heater are controlled to have a constant output, but the heater or heater may also be configured to change the cooling operation amount or heating operation amount by output feedback control or state feedback control.

[0071] The temperature estimation observer may be configured as a Kalman filter in consideration of the influence of disturbances. Various existing methods may be used to set a Kalman gain instead of the observer gain.

[0072] Furthermore, the heater 31 of the embodiment can form a temperature distribution on the suction plate 2 by using the multiple heater electrodes 31a. For example, the heater 31 can make the heating amount different between the center and the outer periphery of the suction plate 2, and can also make the heating amount different between a large area roughly in a C-shape on the outer periphery and the remaining small area. That is, three heating areas are set on the suction plate 2, thereby forming a temperature distribution on the suction plate 2. The cooler 32 may also be configured to form three cooling areas on the surface of the base plate 32a in correspondence with the three heating areas of the suction plate 2.

[0073] The heating or cooling region of the wafer W and the suction plate 2 is not limited to being divided into three regions, and may be divided into more regions or may be divided into two regions. Also, the wafer W or the suction plate 2 as a whole may be treated as one temperature without setting regions. Also, the suction plate 2 may not have a suction function and may simply be a plate on which the wafer W is placed.

[0074] The present invention described above is an aspect in which the set temperature of the wafer is corrected using a nonlinear relationship between the wafer temperature and the pressure of the heat transfer gas, but it may also be an aspect in which the set temperature of the wafer is corrected using a nonlinear relationship between the wafer temperature and the temperature of the temperature regulator. Specifically, the temperature estimation observer 10 estimates the temperature T W The temperature estimation observer 10 uses a state space model in which the relationship between the temperature T of the wafer W and the temperature of the temperature regulator 3 is linear. W The controller 11 uses a state space model in which the relationship between the temperature T of the wafer W and the temperature of the heater 31 and / or the cooler 32 is linear. Wand the temperature of the heater 31 and / or the cooler 32, the set temperature T SET After correcting, the set temperature T SET ' and the estimated wafer temperature T W_est The temperature manipulated variable (heating manipulated variable and / or cooling manipulated variable) may be controlled so as to reduce the temperature deviation from the temperature of the temperature control unit 100.

[0075] The configuration of the cooler or heater is not limited to those described above. For example, the cooler may be configured using a Peltier element, and the heater is not limited to a heater electrode but may be configured to heat the wafer by irradiating light.

[0076] The location measured by the proximity temperature sensor is not limited to the above-mentioned location, but may be other locations. In short, any temperature that is likely to have some correlation or relationship with the wafer temperature may be measured as the proximity temperature. Also, the controller is not limited to an infrared temperature sensor, but may be, for example, a thermocouple provided in the plate.

[0077] In addition, various modifications and combinations of the embodiments may be made as long as they do not go against the spirit of the present invention. [Explanation of symbols]

[0078] 100 Wafer temperature control device 2. Adsorption plate (plate) 3...Temperature regulator 31...heater 32...Cooler 4 Gas supply mechanism 43 Pressure regulator 5. Near-field temperature sensor 10 Temperature estimation observer 10a Temperature estimation model 10b Wafer temperature output section 10c Near-field temperature output section 10d Observer Gain 11 Controller

Claims

1. A wafer temperature control device in which a wafer is placed on a temperature-adjusted plate and a heat transfer gas is supplied between the plate and the wafer to control the temperature of the wafer, a pressure regulator for adjusting the pressure of the heat transfer gas; a proximity temperature sensor for measuring a proximity temperature of the wafer; a temperature estimation observer that estimates a temperature of the wafer based on a nearby temperature measured by the nearby temperature sensor and a pressure manipulation amount input to the pressure regulator or a pressure adjusted by the pressure regulator; a controller that controls the pressure manipulated variable based on a set temperature of the wafer and an estimated wafer temperature estimated by the temperature estimation observer.

2. the temperature estimation observer uses a state space model in which a relationship between the temperature of the wafer and the pressure of the heat transfer gas is linear; 2. The wafer temperature control device of claim 1, wherein the controller corrects the set temperature using a nonlinear relationship between the wafer temperature and the pressure of the heat transfer gas that has been acquired in advance, and controls the pressure manipulation variable so that a temperature deviation between the corrected set temperature and the estimated wafer temperature is reduced.

3. The controller includes: a relational data storage unit for storing nonlinear relational data indicating a nonlinear relation between the temperature of the wafer and the pressure of the heat transfer gas previously acquired, and linear relational data indicating a linear relation between the temperature of the wafer and the pressure of the heat transfer gas used in a state space model of the temperature estimation observer, A converted pressure that nonlinearly corresponds to the set temperature is obtained from the set temperature and the nonlinear relationship data; 3. The wafer temperature control apparatus according to claim 2, further comprising: a converted temperature that linearly corresponds to the converted pressure is determined from the converted pressure and the linear relationship data; and the converted temperature is set as the corrected set temperature.

4. The temperature estimation observer a temperature estimation model which is a linear state space model having the wafer temperature and the vicinity temperature as output variables; a wafer temperature output unit that outputs the estimated wafer temperature estimated based on the temperature estimation model; a vicinity temperature output unit that outputs an estimated vicinity temperature estimated based on the temperature estimation model; an observer gain; 4. A wafer temperature control device as described in any one of claims 1 to 3, configured so that the deviation between the estimated nearby temperature output from the nearby temperature output unit and the nearby temperature measured by the nearby temperature sensor, or a value calculated from the deviation multiplied by the observer gain, is fed back into the temperature estimation model.

5. The temperature estimation observer a temperature estimation model which is a linear state space model having the wafer temperature and the vicinity temperature as output variables; a wafer temperature output unit that outputs the estimated wafer temperature estimated based on the temperature estimation model; a vicinity temperature output unit that outputs an estimated vicinity temperature estimated based on the temperature estimation model; a proximity temperature correction unit that corrects the estimated proximity temperature output from the proximity temperature output unit in consideration of a nonlinear characteristic of the temperature of the plate; an observer gain; 4. A wafer temperature control device as described in any one of claims 1 to 3, configured so that the deviation between the corrected estimated nearby temperature output from the nearby temperature correction unit and the nearby temperature measured by the nearby temperature sensor, or a value calculated from the deviation multiplied by the observer gain, is fed back into the temperature estimation model.

6. The apparatus of claim 4 , wherein the temperature estimation observer comprises the temperature estimation model responsive to a temperature of the temperature-conditioned plate.

7. A wafer temperature control device as described in claim 5, wherein the temperature estimation observer is provided with a temperature estimation model corresponding to the temperature of the temperature-adjusted plate.

8. 1. A wafer temperature control method comprising: placing a wafer on a temperature-adjusted plate; and supplying a heat transfer gas between the plate and the wafer to control the temperature of the wafer, the method comprising the steps of: The pressure of the heat transfer gas is adjusted by a pressure regulator; measuring a temperature near the wafer with a proximity temperature sensor; estimating a temperature of the wafer using a temperature estimation observer based on the vicinity temperature measured by the vicinity temperature sensor and a pressure manipulation amount input to the pressure regulator or a pressure adjusted by the pressure regulator; The wafer temperature control method further comprises controlling the pressure manipulation amount based on a set wafer temperature and an estimated wafer temperature estimated by the temperature estimation observer.

9. A wafer temperature control program for use in a wafer temperature control device in which a wafer is placed on a temperature-regulated plate, and a heat transfer gas is supplied between the plate and the wafer to control the temperature of the wafer, the wafer temperature control program including a pressure regulator for adjusting the pressure of the heat transfer gas and a proximity temperature sensor for measuring a temperature in the vicinity of the wafer, the program comprising: a function as a temperature estimation observer that estimates the temperature of the wafer based on the vicinity temperature measured by the vicinity temperature sensor and the pressure manipulation amount input to the pressure regulator or the pressure adjusted by the pressure regulator; a wafer temperature control program that provides a computer with a function as a controller that controls the pressure manipulation amount based on the wafer set temperature and the estimated wafer temperature estimated by the temperature estimation observer;

10. a temperature controller that controls the temperature of the wafer according to an input temperature control amount; a proximity temperature sensor for measuring a proximity temperature of the wafer; a temperature estimation observer that estimates a temperature of the wafer based on the vicinity temperature measured by the vicinity temperature sensor and a temperature manipulation variable input to the temperature controller or a temperature of the temperature controller; a controller that controls the temperature manipulated variable based on a set temperature of the wafer and an estimated wafer temperature estimated by the temperature estimation observer; the temperature estimation observer uses a state space model in which a relationship between the temperature of the wafer and the temperature of the temperature regulator is linear; The controller corrects the set temperature using a nonlinear relationship between the wafer temperature and the temperature of the temperature regulator that is acquired in advance, and controls the temperature manipulation variable so that the temperature deviation between the corrected set temperature and the estimated wafer temperature is reduced.

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