Parameter estimation system, parameter estimation method, computer program, and substrate processing apparatus

Abstract

The invention provides a parameter estimation system, a parameter estimation method, a computer program, and a substrate processing apparatus. A parameter estimation system is a parameter estimation system in a substrate processing apparatus provided with a substrate mounting table and a cooling base for adjusting the temperature of the substrate mounting table via a cooling layer, the parameter estimation system being provided with: an acquisition unit for acquiring the temperature of the substrate mounting table; the temperature-time series data acquisition unit acquires temperature-time series data obtained by measuring the temperature of the substrate mounting table in time series when the temperature of the substrate mounting table is raised. A model calculation unit that calculates a temperature transition of the substrate mounting table using the physical model; an error calculation unit that calculates an error between the temperature time-series data acquired by the acquisition unit and the temperature transition data acquired from the model calculation unit; and an estimation unit that estimates, on the basis of the error calculated by the error calculation unit, a parameter including a value of heat input to the substrate mounting table and a value of thermal resistance of the cooling layer in the physical model.

Description

Technical Field

[0001] The present disclosure relates to a parameter estimation system, a parameter estimation method, a computer program, and a substrate processing apparatus. Background Art

[0002] Patent Document 1 discloses a plasma processing apparatus that measures the temperature of a substrate support body by a sensor and has a function of adjusting the temperature of the substrate support body based on the measured value.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2008-85329 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] The present disclosure provides a parameter estimation system, a parameter estimation method, a computer program, and a substrate processing apparatus capable of estimating parameters in a physical model for calculating temperature transition of a substrate mounting table.

[0008] Solutions for solving problems

[0009] A parameter estimation system involved in one embodiment of the present disclosure is a parameter estimation system in a substrate processing device having a substrate mounting table and a cooling base for adjusting the temperature of the substrate mounting table via a cooling layer, the parameter estimation system comprising: an acquisition unit, which acquires temperature time series data obtained by measuring the temperature of the substrate mounting table in a time series when the temperature of the substrate mounting table is increased; a model calculation unit, which uses a physical model to calculate the temperature shift of the substrate mounting table; an error calculation unit, which calculates the error between the temperature time series data acquired by the acquisition unit and the temperature shift data obtained from the model calculation unit; and an estimation unit, which estimates parameters in the physical model, including the value of heat input to the substrate mounting table and the value of thermal resistance of the cooling layer, based on the error calculated by the error calculation unit.

[0010] Effects of the Invention

[0011] According to the present disclosure, it is possible to estimate parameters in a physical model for calculating the temperature transition of a substrate mounting table. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram showing a configuration example of a plasma processing system.

[0013] Figure 2 It is an explanatory diagram for explaining a substrate temperature adjustment mechanism.

[0014] Figure 3 This is a graph showing the time change of the temperature of the electrostatic holding disk.

[0015] Figure 4A This is a graph showing changes in the temperature rise curve when the parameters are changed.

[0016] Figure 4B This is a graph showing changes in the temperature rise curve when the parameters are changed.

[0017] Figure 5 This is a graph showing the distribution of errors when the parameters are changed.

[0018] Figure 6 is a graph showing the distribution of errors in the diagonal direction.

[0019] Figure 7 : is a flowchart showing the procedure of a process executed by the control unit of the plasma processing system.

[0020] Figure 8 This is a flowchart showing the procedure of processing executed by the processing unit in the second embodiment.

[0021] Fig. 9 This is a flowchart showing the procedure of processing executed by the processing unit in the third embodiment.

[0022] Fig.10 This is a flowchart showing the procedure of processing executed by the processing unit in the fourth embodiment.

[0023] Fig.11 Schematic diagram showing the structure of an electrostatic holding disk in the fifth embodiment. DETAILED DESCRIPTION

[0024] Hereinafter, the present invention will be described in detail based on the accompanying drawings showing embodiments of the present invention.

[0025] (Implementation Method 1)

[0026] Figure 11 is a schematic diagram showing a structural example of a plasma processing system 1. In one embodiment, the plasma processing system 1 includes a plasma processing device 1a and a control unit 1b. The plasma processing device 1a includes a plasma processing chamber 10, a gas supply unit 20, an RF (Radio Frequency) power supply unit 30, and an exhaust system 40. In addition, the plasma processing device 1a includes a support unit 11 and an upper electrode shower head 12. The support unit 11 is arranged in a lower area of ​​the plasma processing space 10s in the plasma processing chamber 10. The upper electrode shower head 12 is arranged above the support unit 11 and can function as a part of the ceiling of the plasma processing chamber 10.

[0027] The support portion 11 is configured to support the substrate W in the plasma processing space 10s. In one embodiment, the support portion 11 includes a lower electrode 111, an electrostatic holding disk 112, and an edge ring 113. The electrostatic holding disk 112 is arranged on the lower electrode 111, and is configured to support the substrate W on the upper surface of the electrostatic holding disk 112. The electrostatic holding disk 112 is formed of ceramic. The edge ring 113 is configured to surround the substrate W on the upper surface of the peripheral portion of the lower electrode 111. In addition, although omitted from the figure, in one embodiment, the support portion 11 may also include a temperature control module, which is configured to adjust at least one of the electrostatic holding disk 112 and the substrate W to a target temperature. The temperature control module may include a heater, a flow path, or a combination thereof. A temperature control fluid such as a refrigerant or a heat transfer gas flows in the flow path.

[0028] The upper electrode shower head 12 is configured to supply one or more processing gases from the gas supply unit 20 to the plasma processing space 10s. In one embodiment, the upper electrode shower head 12 has a gas inlet 12a, a gas diffusion chamber 12b, and a plurality of gas outlets 12c. The gas inlet 12a is fluidly connected to the gas supply unit 20 and the gas diffusion chamber 12b. The plurality of gas outlets 12c are fluidly connected to the gas diffusion chamber 12b and the plasma processing space 10s. In one embodiment, the upper electrode shower head 12 is configured to supply one or more processing gases from the gas inlet 12a to the plasma processing space 10s via the gas diffusion chamber 12b and the plurality of gas outlets 12c.

[0029] The gas supply unit 20 may include one or more gas sources 21 and one or more flow controllers 22. In one embodiment, the gas supply unit 20 is configured to supply one or more processing gases from the respective corresponding gas sources 21 to the gas inlet 12a via the respective corresponding flow controllers 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. In addition, the gas supply unit 20 may also include one or more flow modulation devices for modulating or pulsing the flow of one or more processing gases.

[0030] The RF power supply unit 30 is configured to supply RF power, for example, one or more RF signals, to one or more electrodes such as the lower electrode 111, the upper electrode shower head 12, or both the lower electrode 111 and the upper electrode shower head 12. Thus, plasma is generated from one or more processing gases supplied to the plasma processing space 10s. Therefore, the RF power supply unit 30 can function as at least a part of a plasma generating unit, which is configured to generate plasma from one or more processing gases in a plasma processing chamber. In one embodiment, the RF power supply unit 30 includes two RF generating units 31a, 31b and two matching circuits 32a, 32b. In one embodiment, the RF power supply unit 30 is configured to supply a first RF signal from a first RF generating unit 31a to the lower electrode 111 via a first matching circuit 32a. For example, the first RF signal may have a frequency in the range of 27MHz to 100MHz.

[0031] In one embodiment, the RF power supply unit 30 is configured to supply a second RF signal from the second RF generator 31b to the lower electrode 111 via the second matching circuit 32b. For example, the second RF signal may have a frequency in the range of 400kHz to 13.56MHz. Alternatively, a DC (Direct Current) pulse generator may be used instead of the second RF generator 31b.

[0032] Furthermore, although not shown in the figure, other embodiments can be considered in the present disclosure. For example, in an alternative embodiment, the RF power supply unit 30 may also be configured to supply a first RF signal from an RF generating unit to the lower electrode 111, supply a second RF signal from another RF generating unit to the lower electrode 111, and supply a third RF signal from yet another RF generating unit to the lower electrode 111. In addition, in other alternative embodiments, a DC voltage may be applied to the upper electrode shower head 12.

[0033] In addition, and in various embodiments, the amplitude of one or more RF signals (i.e., the first RF signal, the second RF signal, etc.) may also be pulsed or modulated. Amplitude modulation may include pulsing the amplitude of the RF signal between an on state and an off state, or between two or more different on states.

[0034] The exhaust system 40 can be connected to, for example, an exhaust port 10e disposed at the bottom of the plasma processing chamber 10. The exhaust system 40 can include a pressure valve and a vacuum pump. The vacuum pump can include a turbomolecular pump, a roughing pump, or a combination thereof.

[0035] In one embodiment, the control unit 1b processes computer-executable commands that cause the plasma processing device 1a to perform various processes described in the present disclosure. The control unit 1b can be configured to control various elements of the plasma processing device 1a to perform various processes described herein. In one embodiment, a part or all of the control unit 1b can also be included in the plasma processing device 1a. The control unit 1b can include, for example, a computer 51. The computer 51 can include, for example, a processing unit (CPU: Central Processing Unit) 511, a storage unit 512, and a communication interface 513. The processing unit 511 can be configured to perform various control operations based on a program stored in the storage unit 512. The storage unit 512 can include a RAM (Random Access Memory), a ROM (Read Only Memory), a HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface 513 can communicate with the plasma processing device 1a via a communication line such as a LAN (Local Area Network).

[0036] The storage unit 512 may also store various computer programs executed by the processing unit 511. The computer programs stored in the storage unit 512 include, for example, a computer program PG, which is used to make the processing unit 511 perform parameter estimation processing used in the physical model for calculating the temperature transition of the electrostatic holding disk 112 (substrate mounting table). The computer program PG is provided via the recording medium RM or communication. The computer program PG may be a single computer program or a program group consisting of a plurality of computer programs. In addition, the computer program PG may also be a program that partially uses an existing program library.

[0037] Figure 21 is an explanatory diagram for explaining a substrate temperature adjustment mechanism. The support portion 11 of the plasma processing device 1a includes a lower electrode 111 and an electrostatic holding disk 112. In the present embodiment, the lower electrode 111 is configured to function as a cooling base for cooling the electrostatic holding disk 112. In addition, the electrostatic holding disk 112 is provided as a substrate mounting table for mounting a substrate W to be processed. The lower electrode 111 and the electrostatic holding disk 112 are bonded by an adhesive layer 110.

[0038] A refrigerant flow path 62 is formed inside the lower electrode 111. Refrigerant is supplied to the refrigerant flow path 62 from a cooling unit 60 provided outside the plasma processing chamber 10 via an inlet pipe 61. An appropriate medium such as salt water is used as the refrigerant. The refrigerant supplied to the refrigerant flow path 62 flows back to the cooling unit 60 via an outlet pipe 63.

[0039] A heater 71 and a temperature sensor 72 are provided inside the electrostatic holding disk 112. The heater 71 is connected to a heater power supply 70 provided outside the plasma processing chamber 10, and is configured to generate heat according to the power supplied from the heater power supply 70, and heat the substrate W placed on the electrostatic holding disk 112. The heater 71 uses, for example, a plurality of resistance heating heaters that can independently heat a plurality of regions of the electrostatic holding disk 112. The temperature sensor 72 is, for example, a thermocouple, and is provided at one or more locations inside the electrostatic holding disk 112. The temperature sensor 72 measures the temperature of the location where it is provided in a time series, and outputs temperature time series data to the control unit 1b.

[0040] As the material of the adhesive layer 110, an adhesive with high thermal conductivity can be used. In the case of focusing on the function of the lower electrode 111 as a cooling base, the adhesive layer 110 functions as a cooling layer provided between the lower electrode 111 (cooling base) and the electrostatic holding disk 112 (substrate mounting table). In addition, as the material of the adhesive layer 110, an adhesive with high electrical resistance can also be used so that it has the function of electrically insulating the lower electrode 111 from the electrostatic holding disk 112. As an adhesive with high thermal conductivity and electrical resistance, for example, an organic adhesive including a silicone-based material, an acrylic-based material or an acrylate-based acrylic-based material, or a polyimide silica-based material can be used.

[0041] The control unit 1b of the plasma processing apparatus 1a controls the cooling unit 60 and the heater power supply 70 based on the temperature of the electrostatic holding disk 112 measured by the temperature sensor 72. That is, the control unit 1b controls the temperature and flow rate of the refrigerant supplied by the cooling unit 60 and controls the magnitude of the power supplied by the heater power supply 70 to the heater 71, thereby adjusting the temperature so that the temperature of the electrostatic holding disk 112 becomes the target temperature.

[0042] In plasma processing, it is desired that the surface temperature of the electrostatic holding disk 112 is uniform over the entire surface area. However, in addition to the above-mentioned heater 71 and temperature sensor 72, the electrostatic holding disk 112 is also provided with various mechanisms such as a plurality of lifting pins for lifting the processed substrate W to a specified height. Due to the mechanical structure of such an electrostatic holding disk 112, points (hereinafter also referred to as singular points) with local high or low temperatures appear on the surface of the electrostatic holding disk 112. In addition, due to the appearance of singular points, the surface temperature distribution of the electrostatic holding disk 112 deviates. The deviation of the surface temperature distribution in the electrostatic holding disk 112 is one reason for the decrease in uniformity when processing the substrate W.

[0043] When estimating the surface temperature distribution of the electrostatic holding disk 112 by simulation using a physical model to analyze the cause of the uniformity reduction, parameters such as heat input to the electrostatic holding disk 112 and thermal conductivity between the electrostatic holding disk 112 and the lower electrode 111 are required. However, as described above, the structure of the electrostatic holding disk 112 is complicated, so it is difficult to accurately estimate these parameters.

[0044] In this embodiment, a method is proposed in which parameters of a physical model including heat input and thermal resistance are estimated using temperature time series data obtained as measured values ​​during the temperature rise of the electrostatic holding disk 112 and temperature transition data calculated using a physical model.

[0045] The physical model for estimating the temperature transition of the electrostatic holding disk 112 is represented by equation 1, for example.

[0046] [Number 1]

[0047]

[0048] Here, ρ represents the density of the electrostatic holding disk 112 (g / m 3 ), c represents the specific heat of the electrostatic holding disk 112 (J / g·K), and A represents the heat flow rate through the cross-sectional area (m 2 ), Δz cer Q represents the thickness of the electrostatic holding disk 112, u represents the temperature of the electrostatic holding disk 112 (K), and t represents time (s). IN represents the heat input (W) to the electrostatic holding disk 112, Q OUT The heat output Q from the electrostatic holding disk 112 to the lower electrode 111 is shown in W. OUT The temperature difference between the lower electrode 111 and the electrostatic holding disk 112 and the thermal resistance R of the adhesive layer 110 can be used. th (mK / W) is used to record.

[0049] Figure 31 is a graph showing the time change of the temperature of the electrostatic holding disk 112. The horizontal axis of the graph represents time (s), and the vertical axis represents the temperature (°C) of the electrostatic holding disk 112. The solid line temperature rise curve represents the measured value, and the dotted line temperature rise curve represents the calculated value of the physical model. The measured temperature rise curve is, for example, when the electrostatic holding disk 112 is heated by the heater 71 to raise the electrostatic holding disk 112 from near room temperature to the target temperature (at Figure 3 The temperature of the electrostatic holding disk 112 is obtained by measuring the temperature of the electrostatic holding disk 112 in a time series by the temperature sensor 72 during the period of 350° C. in the example. Instead of heating by the heater 71, plasma may be generated in the plasma processing chamber 10, and the electrostatic holding disk 112 may be heated using the generated plasma. During the period of heating the electrostatic holding disk 112, not only heat input from the heater 71 (or plasma) to the electrostatic holding disk 112 but also heat output from the electrostatic holding disk 112 to the lower electrode 111 is generated.

[0050] The temperature rise curve of the physical model is obtained by setting the parameters in the physical model to appropriate values ​​and calculating the temperature (u) at each time according to the physical model. As the parameters in the physical model, the heat input (=Q IN ), and participate in heat output Q OUT Thermal resistance R th (or its reciprocal thermal conductivity k).

[0051] Figure 3 The example shows that there is a deviation between the measured temperature rise curve and the temperature rise curve of the physical model, and there is room for improvement in the parameters of the physical model.

[0052] Figure 4A and Figure 4B 2 is a graph showing changes in the temperature rise curve when the parameters are changed. The horizontal axis of the graph represents time (s), and the vertical axis represents the temperature (° C.) of the electrostatic holding disk 112 . Figure 4A The thermal resistance R th The variation range of the temperature rise curve when the value of changes. In the physical model of equation 1, the thermal resistance R th When the value of is changed in various ways, the heating curve obtained by this physical model is Figure 4A The range shown by the shading is as follows. Figure 4A As can be seen from the graph, even if the thermal resistance R th When the value of changes, the heating rate in the low temperature region (for example, less than 200°C) hardly changes and is roughly constant. On the other hand, it can be seen that the heating rate in the high temperature region (for example, above 250°C) varies according to the thermal resistance R th The value of thermal resistance R th It helps to measure the time until the temperature u reaches the saturation temperature.

[0053] Figure 4B The heat input Q IN The range of variation of the temperature rise curve when the value of is changed. In the physical model of equation 1, the heat input Q IN When the value of is changed in various ways, the heating curve obtained by this physical model is Figure 4B The range shown by the shading is as follows. Figure 4B As can be seen from the graph, even when the heat input Q IN When the value of changes, the time until the temperature u of the electrostatic holding disk 112 reaches the saturation temperature is also approximately constant. On the other hand, it can be seen that the heating rate in the low temperature region (for example, less than 200°C) varies according to the heat input Q IN varies with the value of .

[0054] As described above, by making the thermal resistance R th The value of Q can change the heating rate in the high temperature area. IN The value of can change the temperature rise rate in the low temperature region. That is, the following insight is obtained: even if the thermal resistance R th and heat input Q IN If only one of the parameters is changed, it is difficult to reproduce the temperature rise curve of the actual measured value. However, if both parameters are changed at the same time, the temperature rise curve obtained by the physical model can be made close to the temperature rise curve of the actual measured value.

[0055] Therefore, in this embodiment, the error between the temperature time series data obtained as the actual measurement value and the temperature transition data calculated using the physical model is calculated, and the parameters (thermal resistance R th and heat input Q IN ).

[0056] Figure 5 2 is a graph showing the distribution of errors when the parameters are changed. The horizontal axis of the graph represents the thermal conductivity k (W / mmK) of the adhesive layer 110, and the vertical axis represents the heat input Q to the electrostatic holding disk 112. IN (W). Thermal conductivity k is thermal resistance R th The inverse of . In addition, the shade of the graph shows the magnitude of the time series error between the temperature time series data obtained as the measured value and the temperature transition data calculated using the physical model. The time series error is expressed, for example, using the mean square error (MSE). i The value of the temperature transition data at time i is set to y i When the mean square error is Σ(Y i -yi ) 2 / n. Here, n represents the total number of data.

[0057] from Figure 5 As can be seen from the graph, the magnitude of the error is relatively large in the upper left and lower right areas of the graph, and decreases as it moves from the upper left and lower right areas to the area near the center, and becomes extremely small in the area along the diagonal line represented by the hollow arrow symbol X. The result of investigating the magnitude of the error along the diagonal line is Figure 6 The distribution shown.

[0058] Figure 6 is a graph showing the distribution of errors in the diagonal direction. Figure 5 The vertical axis represents the magnitude of the error for the points on the diagonal line indicated by the hollow arrow symbol X. In addition, the horizontal axis represents the coordinates rescaled in such a way that one end of the diagonal line is 0 and the other end is 100.

[0059] like Figure 6 As shown, it can be seen that the size of the error on the diagonal line is not constant. At a certain point (at Figure 6 In the example, the thermal conductivity k is 2.3×10 -4 (W / mmK) and heat input Q IN The power is minimum at the point where the power is 5600(W).

[0060] That is, when the errors between the temperature time series data obtained as the actual measured values ​​and the temperature transition data calculated using the physical model are calculated, the values ​​of the thermal resistance and heat input that minimize the calculated errors can be uniquely determined. In addition, the physical model can be optimized by using the values ​​of the thermal resistance and heat input that minimize the errors as parameters.

[0061] Figure 7 1 is a flowchart showing the process performed by the control unit 1b of the plasma processing system 1. The control unit 1b of the plasma processing system 1 controls the operation of the plasma processing device 1a to increase the temperature of the electrostatic holding disk 112 (step S101). The control unit 1b can increase the temperature of the electrostatic holding disk 112 by operating the heater power supply 70 so that the heater 71 heats the electrostatic holding disk 112. In addition, the control unit 1b can also increase the temperature of the electrostatic holding disk 112 by operating the RF power supply unit 30 and the like to generate plasma in the plasma processing chamber 10. The temperature of the electrostatic holding disk 112 during the temperature increase is measured by the temperature sensor 72 in a time series.

[0062] The processing unit 511 acquires temperature time series data obtained by measuring the temperature of the electrostatic holding disk 112 during temperature increase in time series, for example, through the communication interface 513 (step S102 ). The acquired temperature time series data is stored in the storage unit 512 .

[0063] The processing unit 511 calculates the temperature transition of the electrostatic holding disk 112 using the physical model shown in Figure 1 (step S103). The physical model and the parameters (initial setting values) used in the physical model are stored in the storage unit 512. The processing unit 511 can calculate the temperature transition of the electrostatic holding disk 112 by reading the physical model and the parameters from the storage unit 512 and performing calculations according to the read physical model and the parameters. The calculated temperature transition data is stored in the storage unit 512.

[0064] In the present embodiment, the process of performing calculation based on the physical model is set after the measured temperature time series data is acquired, but the execution order of these processes can be performed sequentially or simultaneously in parallel.

[0065] The processing unit 511 calculates the error between the temperature time series data acquired in step S102 and the temperature transition data calculated in step S103 (step S104). The processing unit 511 may calculate the time series error between the temperature time series data obtained as the actual measurement value and the temperature transition data calculated using the physical model, for example, by calculating the mean square error between the temperature time series data obtained as the actual measurement value and the temperature transition data calculated using the physical model.

[0066] The processing unit 511 estimates the heat input Q to the electrostatic holding disk 112 in the physical model based on the calculated error. IN and participate in heat output Q OUT Thermal resistance R th Specifically, the processing unit 511 uses the finite difference time domain method (FDTD) to determine the heat input Q in such a way as to minimize the error calculated in step S104. IN The value and thermal resistance R th (or thermal conductivity k) value.

[0067] The processing unit 511 optimizes the physical model by updating the parameters (step S106). The processing unit 511 can optimize the physical model by updating the parameters (step S106). IN The value and thermal resistance R th The value of (or thermal conductivity k) is stored in the storage unit 512 as a new parameter to optimize the physical model.

[0068] exist Figure 7In the flowchart, a process of optimizing the physical model according to the calculated error is set, but it can also be set as the following process: when the calculated error is larger than the threshold, the physical model is optimized, and when the calculated error is smaller than the threshold, the physical model is not optimized.

[0069] As described above, in this embodiment, the heat input Q can be estimated in the process of fitting the temperature transition data obtained from the physical model with the temperature time series data obtained as actual measurement. IN Thermal resistance R th In addition, the estimation method of the present disclosure can be implemented by simply preparing measured temperature time series data, so that automatic estimation can be performed during the execution of the process (i.e., there is no need to arrange the process for analysis), which has the advantage of not affecting the user's productivity.

[0070] In the present embodiment, the temperature is measured using the temperature sensor 72 built into the electrostatic holding disk 112. However, there is no limitation on the number of sensors or the type of sensors provided as long as the temperature of the electrostatic holding disk 112 can be measured in time series. For example, a plurality of temperature sensors 72 may be built into the electrostatic holding disk 112 to measure the temperature distribution within the surface at each time, and the temperature of the electrostatic holding disk 112 may be measured in time series by each temperature sensor 72. In this case, it is preferable to prepare a physical model for each temperature sensor 72 and optimize the physical model based on the temperature time series data obtained from each temperature sensor 72.

[0071] As the temperature sensor 72, an infrared camera that captures images of radiant heat emitted from the surface of the electrostatic holding disk 112 may be used. The infrared camera is set to face the surface of the electrostatic holding disk 112, and outputs an image representing the surface temperature distribution of the electrostatic holding disk 112 in a time series. In this case, the temperature u included in the physical model is expressed as a function of time and position. The processing unit 511 only needs to obtain the time series data (image data) of the surface temperature distribution from the infrared camera, and use the physical model to calculate the surface temperature distribution at each time, and estimate the parameters included in the physical model in a way that minimizes the error between the two.

[0072] In the present embodiment, the temperature time series data when the temperature of the electrostatic holding disk 112 is increased is used. However, it is needless to say that the temperature time series data when the temperature of the electrostatic holding disk 112 is decreased may also be used.

[0073] (Implementation Method 2)

[0074] In the second embodiment, an operation mode of the plasma processing system 1 will be described.

[0075] Figure 8 1 is a flowchart showing the process of processing performed by the processing unit 511 in the second embodiment. The processing unit 511 performs parameter estimation processing (step S201) every time it processes a set number of substrates W. The set number of substrates is set in advance. In one example, the set number of substrates is 500. The operating time of the plasma processing device 1a may be used instead of the set number of substrates. The processing unit 511 performs parameter estimation processing (step S201) every time it processes a set number of substrates W. Figure 7 The parameter estimation process is performed by the process of steps S101 to S105 shown in the flowchart.

[0076] The processing unit 511 converts the estimated parameters (ie, heat input Q IN and thermal resistance R th The value of ) is associated with the total number of processed sheets and stored in the storage unit 512 (step S202).

[0077] The processing unit 511 determines the estimated latest heat input Q IN When the surface temperature distribution of the electrostatic holding disk 112 is used as the temperature time series data, the heat input Q can be monitored. IN The in-plane distribution of IN The uniformity of plasma density is evaluated by the in-plane distribution of

[0078] The estimated latest heat input Q IN When the value of is less than the first threshold value TH1 (S203: Yes), it can be determined that the plasma density may be non-uniform, so the processing unit 511 notifies the user of the change in process conditions (step S204). For example, the processing unit 511 sends the notification of the change in process conditions to the portable terminal held by the user through the communication interface 513. Alternatively, the processing unit 511 may also display the information of the change in process conditions on a display unit not shown in the figure.

[0079] The estimated latest heat input Q IN When the value of is greater than the first threshold value TH1 (S203: No), or when a notification to change the process conditions is made in step S204, the processing unit 511 determines the estimated latest thermal resistance R th The processing unit 511 monitors the thermal resistance R th The value of can be used to evaluate the degree of consumption of the adhesive layer 110.

[0080] The estimated thermal resistance R thWhen the value of exceeds the second threshold value TH2 (S205: "Yes"), it can be determined that the electrostatic holding disk 112 is deteriorating as the adhesive layer 110 is consumed by the influence of free radicals and heat, so the processing unit 511 outputs a warning to urge replacement of the component (step S206). For example, the processing unit 511 sends the warning to urge replacement of the component to the portable terminal held by the user through the communication interface 513. Alternatively, the processing unit 511 may also display the warning to urge replacement of the component on a display unit not shown in the figure.

[0081] As described above, in the second embodiment, the parameter estimation process is executed for each set number of sheets. The processing unit 511 can estimate the heat input Q IN The value of can be used to monitor the uniformity of plasma density, so that the process conditions can be changed before the yield rate deteriorates. In addition, the thermal resistance R can be estimated. th , to monitor the degree of consumption of the adhesive layer 110, so that a warning can be output before the electrostatic holding disk 112 reaches the end of its life.

[0082] (Implementation 3)

[0083] In the third embodiment, a configuration is described in which the heat input Q estimated in the above-mentioned estimation process is used. IN and thermal resistance R th The heater output value is calculated based on the value of to drive and control the heater 71.

[0084] Fig. 9 1 is a flowchart showing the process performed by the processing unit 511 in the third embodiment. The processing unit 511 estimates the heat input Q in the same process as the first embodiment in the preparation process before the actual process of substrate processing. IN and thermal resistance R th In the preparation process, a simulated wafer is placed on the electrostatic holding disk 112, and the temperature of the electrostatic holding disk 112 is raised from room temperature to a target temperature while plasma is generated. The target temperature is set to the process temperature in the formal processing process. As in the first embodiment, the processing unit 511 estimates the heat input Q by fitting the temperature transition data obtained by the physical model with the measured temperature time series data. IN and thermal resistance R th The value of .

[0085] The processing unit 511 calculates the heat input Q based on the estimated heat input Q IN and thermal resistance R th The value of Q is used to calculate the heater output value required to make the electrostatic holding disk 112 reach the target temperature from room temperature (step S302). This step is preferably performed before the actual processing step of processing the substrate W. The processing unit 511 uses the heat input Q to INand thermal resistance R th The heater output value is calculated by using a conversion formula or table learned in advance to output the heater output value from room temperature to the target temperature when the value and target temperature are obtained. The heater output value does not need to be constant, but can also be a value that changes from room temperature to the target temperature.

[0086] The processing unit 511 drives and controls the heater 71 based on the calculated heater output value (step S303). In the actual processing step of substrate processing, the processing unit 511 drives and controls the heater 71 by controlling the output of the heater power supply 70 to the heater output value calculated in step S302 through the control unit 1b.

[0087] As described above, in the third embodiment, it is possible to obtain the heat input Q IN and thermal resistance R th The drive control of the heater 71 is performed based on the value of , so that, for example, temperature overshoot can be prevented in advance at the start of the process.

[0088] (Implementation 4)

[0089] In Embodiment 4, the estimated heat input Q IN The structure of the gas amount in the substrate surface is adjusted according to the estimated in-plane distribution.

[0090] Fig.10 4 is a flowchart showing the process performed by the processing unit 511 in the fourth embodiment. The processing unit 511 estimates the heat input Q in the same process as in the first embodiment in a preparatory process before the actual process of performing substrate processing. IN and thermal resistance R th In the preparation process, a simulated wafer is placed on the electrostatic holding disk 112, and the temperature of the electrostatic holding disk 112 is raised from room temperature to a target temperature while plasma is generated. The target temperature is set to the process temperature in the formal processing process. As in the first embodiment, the processing unit 511 estimates the heat input Q by fitting the temperature transition data obtained by the physical model with the measured temperature time series data. IN and thermal resistance R th The value of .

[0091] In the fourth embodiment, a plurality of temperature sensors 72 are used or an infrared camera is used as the temperature sensor 72 to estimate the heat input Q for each of the plurality of regions within the substrate surface. IN and thermal resistance R th The processing unit 511 calculates the value of the heat input Q of each area based on the heat input Q IN The value of heat input Q IN The in-plane distribution of (step S401).

[0092] The processing unit 511 calculates the heat input Q based on the estimated heat input Q IN In the actual processing step of substrate processing, the processing unit 511 controls the operation of the gas supply unit 20 through the control unit 1b to adjust the gas volume in each area of ​​the substrate surface, for example, to achieve a plasma density that can obtain an ideal etching shape.

[0093] As described above, in the fourth embodiment, according to the heat input Q IN The gas amount in each area within the substrate surface can be adjusted by adjusting the in-plane distribution, thereby controlling the plasma density in each area and optimizing the etching shape.

[0094] (Implementation method 5)

[0095] In the fifth embodiment, a structure in which the electrostatic holding disk 112 includes a convex portion will be described.

[0096] Fig.11 Schematic diagram showing the structure of the electrostatic holding disk 112 in Embodiment 5. Fig.11 In the schematic diagram of FIG. 1 , in addition to the electrostatic holding disk 112 , an adhesive layer 110 , a lower electrode 111 , and a substrate W are shown. The structure and function of the adhesive layer 110 and the lower electrode 111 are the same as those of the first embodiment.

[0097] The electrostatic holding disk 112 in Embodiment 5 has a plurality of convex portions 112a for placing substrates W. The substrate W to be processed is placed on the upper surface of the convex portions 112a. The convex portions 112a and the main body of the electrostatic holding disk 112 are integrally formed of ceramic. A heat transfer gas such as He gas is supplied to the gap 112b generated when the substrate W is placed on the upper surface of the convex portions 112a.

[0098] The processing unit 511 in the fifth embodiment estimates the heat input Q to the substrate W placed on the convex portion 112a through the same process as in the first embodiment. IN That is, the processing unit 511 can estimate the heat input Q by fitting the temperature transition data obtained from the physical model with the temperature time series data obtained as actual measurement. IN and thermal resistance R th In the fifth embodiment, a wafer-type temperature sensor may be used as the temperature sensor 72 to measure the temperature of each convex portion 112a.

[0099] Alternatively, the processing unit 511 may apply the same process as in the second embodiment to convert the thermal resistance R estimated for each convex portion 112a into thThe value is compared with a preset value, and the consumption of each protrusion 112a is detected based on the comparison result. In addition, when the processing unit 511 detects the consumption of the protrusion 112a during the formal processing step of the substrate processing or the temperature adjustment step without igniting the plasma, it can also output a warning to prompt the replacement of the parts.

[0100] As described above, in the fifth embodiment, the thermal resistance R of each convex portion 112 a which is difficult to obtain individually can be estimated with high accuracy. th The value of .

[0101] The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the above meaning, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0102] The matters described in each embodiment can be combined with each other. In addition, the independent claims and dependent claims described in the claims can be combined with each other in all combinations regardless of the reference form. Moreover, the claims use a form of recording claims that reference two or more other claims (multiple claim form), but are not limited to this. It is also possible to record multiple claims that reference at least one multiple claim (multiple-reference-multiple claims).

[0103] Description of Reference Numerals

[0104] 1: plasma processing system; 1a: plasma processing device; 1b: control unit; 71: heater; 72: temperature sensor; 110: adhesive layer; 111: lower electrode; 112: electrostatic holding disk; 511: processing unit; 512: storage unit; 513: communication interface.

Claims

1. A parameter estimation system in a substrate processing apparatus including a substrate stage and a cooling base for adjusting the temperature of the substrate stage via a cooling layer, the parameter estimation system comprising: an acquisition unit that acquires temperature time series data obtained by measuring the temperature of the substrate stage in time series when the temperature of the substrate stage is increased; a model calculation unit that calculates a temperature change of the substrate mounting table using a physical model; an error calculation unit that calculates an error between the temperature time series data acquired by the acquisition unit and the temperature transition data obtained from the model calculation unit; as well as An estimating unit estimates parameters including a value of heat input to the substrate mounting table and a value of thermal resistance of the cooling layer in the physical model based on the error calculated by the error calculating unit.

2. The parameter estimation system according to claim 1, wherein: The substrate mounting table is an electrostatic holding disk that attracts the substrate when a DC voltage is applied thereto.

3. The parameter estimation system according to claim 1, wherein: The substrate mounting table is formed of ceramics.

4. The parameter estimation system according to claim 1, wherein: The substrate mounting table has a built-in temperature sensor.

5. The parameter estimation system according to claim 1, wherein: The substrate mounting table includes a heater for temperature control.

6. The parameter estimation system according to claim 5, wherein: The substrate processing apparatus calculates a heater output value until the substrate mounting table reaches a set temperature based on the heat input value estimated by the estimation unit and the thermal resistance value, and drives and controls the heater based on the calculated heater output value.

7. The parameter estimation system according to claim 1, wherein: In a preparation step before a main processing step of performing substrate processing, the estimation unit estimates the in-plane distribution of heat input to the substrate stage. The substrate processing apparatus adjusts the amount of gas in a substrate surface based on the in-plane distribution of the heat input estimated by the estimation unit, and performs a main processing step of processing the substrate.

8. The parameter estimation system according to claim 1, wherein: A detection unit is further provided for comparing the value of the thermal resistance estimated by the estimation unit with a set value of the thermal resistance and detecting consumption of the cooling layer based on a comparison result.

9. The parameter estimation system according to claim 8, wherein: An output unit is further provided for outputting a warning to urge component replacement when the detection unit detects consumption of the cooling layer in a main processing step of substrate processing or a temperature adjustment step in which plasma is not ignited.

10. The parameter estimation system according to claim 1, wherein: The estimation unit performs estimation every time a set number of substrates are processed. The value of the heat input and the value of the thermal resistance estimated by the estimation unit are associated with the number of substrates to be processed and stored in a storage device.

11. The parameter estimation system according to claim 1, wherein: The substrate mounting table is provided with a convex portion for mounting the substrate. The estimation unit estimates a value of heat input to a substrate placed on the protrusion and a thermal resistance of the protrusion.

12. The parameter estimation system according to claim 11, wherein: The temperature of the substrate mounting table is measured by a wafer-type temperature sensor mounted on the protrusion.

13. The parameter estimation system according to claim 11, wherein: A detection unit is further provided for comparing the value of the thermal resistance estimated by the estimation unit with a set value of the thermal resistance and detecting consumption of the convex portion based on a comparison result.

14. The parameter estimation system according to claim 13, wherein: An output unit is further provided for outputting a warning to urge replacement of the component when the detection unit detects consumption of the protrusion in a main processing step of processing the substrate or a temperature adjustment step in which plasma is not ignited.

15. The parameter estimation system according to claim 1, wherein: The estimation section estimates the parameter in the physical model in such a manner as to minimize the error.

16. A parameter estimation method, wherein a computer performs the following processing: In a substrate processing apparatus including a substrate stage and a cooling base for adjusting the temperature of the substrate stage via a cooling layer, temperature time series data obtained by measuring the temperature of the substrate stage in time series when the temperature of the substrate stage is increased, The temperature change of the substrate stage is calculated using a physical model. Calculating the error between the acquired temperature time series data and the temperature transition data obtained from the physical model, Based on the calculated error, parameters in the physical model including a value of heat input to the substrate stage and a value of thermal resistance of the cooling layer are estimated.

17. A computer program for causing a computer to execute the following processing: In a substrate processing apparatus including a substrate stage and a cooling base for adjusting the temperature of the substrate stage via a cooling layer, temperature time series data obtained by measuring the temperature of the substrate stage in time series when the temperature of the substrate stage is increased, The temperature change of the substrate stage is calculated using a physical model. Calculating the error between the acquired temperature time series data and the temperature transition data obtained from the physical model, Based on the calculated error, parameters in the physical model including a value of heat input to the substrate stage and a value of thermal resistance of the cooling layer are estimated.

18. A substrate processing apparatus comprising the parameter estimation system according to any one of claims 1 to 15.

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