Material vaporization system, material vaporization method, and material vaporization program

Abstract

The present invention makes it possible to stably control the flow rate of a material gas while accurately controlling a parameter relating to the amount of a material. The present invention comprises: a vaporizer 21 that vaporizes a material to generate a material gas; a supply amount adjustment device 22 that adjusts the supply amount of the material to be supplied to the vaporizer 21; and a control device 4 that controls the supply amount adjustment device 22. The control device 4 has: an estimate value calculation unit 44 that calculates an estimate value of the parameter relating to the amount of the material in the vaporizer 21 on the basis of the supply amount Qin of the material supplied to the vaporizer 21 and the discharge amount Qout of the material gas discharged from the vaporizer 21; and a supply amount control unit 45 that controls the supply amount adjustment device 22 on the basis of the estimate value.

Description

Material vaporization system, material vaporization method, and material vaporization program

[0001] This invention relates to a material vaporization system, a material vaporization method, and a material vaporization program.

[0002] Conventionally, as shown in Patent Document 1, vaporizers that vaporize liquid materials have been used to generate gases used in semiconductor manufacturing processes, such as thin-film deposition processes.

[0003] This vaporizer comprises a tank for heating a liquid material to generate gas, a gas supply valve for starting or stopping the supply of the generated gas, and a flow rate control means for controlling the flow rate of gas flowing out of the gas supply valve.

[0004] Furthermore, this vaporizer is equipped with a liquid material charging pipe that supplies liquid material to a tank, and the tank is equipped with a liquid level sensor to detect the amount of liquid material stored. When the liquid level detected by the liquid level sensor falls below a predetermined level, the liquid material charging pipe is configured to supply liquid material to the tank.

[0005] International Publication No. 2020 / 195349

[0006] However, in a configuration where the supply of liquid material is started when the liquid level detected by the liquid level sensor falls below a predetermined level, as described above, the pressure inside the tank (storage container) changes significantly (see Figure 10). As a result of the pressure change inside the storage container, the flow rate of the material gas discharged from the storage container becomes unstable, making it difficult to control the stable flow rate of the material gas.

[0007] Therefore, the present invention was made to solve the above-mentioned problems, and its main objective is to enable stable flow rate control of the material gas while accurately controlling parameters related to the amount of material.

[0008] In other words, the material vaporization system according to the present invention comprises a vaporizer that vaporizes a material to generate a material gas, a supply amount adjustment device that adjusts the amount of material supplied to the vaporizer, and a control device that controls the supply amount adjustment device, wherein the control device includes an estimation value calculation unit that calculates estimated values ​​of parameters related to the amount of material in the vaporizer based on the amount of material supplied to the vaporizer and the amount of material gas discharged from the vaporizer, and a supply amount control unit that controls the supply amount adjustment device based on the estimated values.

[0009] With this type of material vaporization system, the amount of material supplied to the vaporizer and the amount of material gas discharged from the vaporizer are input, and estimated values ​​of parameters related to the amount of material in the vaporizer are calculated. Based on these estimated values, the supply adjustment equipment is controlled, so that parameters related to the amount of material, such as the liquid level, can be controlled with high precision. By controlling parameters related to the amount of material, such as the liquid level, with high precision, pressure fluctuations within the vaporizer can be suppressed, thus enabling stable flow rate control of the material gas.

[0010] One possible specific implementation of the estimation unit is that it uses a vaporizer model that simulates the vaporizer to calculate estimated values ​​of parameters related to the amount of material based on the supply amount of the material and the output amount of the material gas.

[0011] In order to accurately calculate estimated values ​​for parameters related to the amount of material in the vaporizer, it is desirable that the estimation unit calculates estimated values ​​for the parameters related to the amount of material based on the supply amount of the material, the output amount of the material gas, and the heater power consumption of the vaporizer. With this configuration, the estimated values ​​can be calculated with high accuracy, so that parameters related to the amount of material, such as the liquid level, can be controlled with high accuracy.

[0012] To accurately reproduce the state in the vaporizer, the vaporizer model is constructed as a nonlinear state-space model. In this case, it is desirable that the estimation unit uses a nonlinear Kalman filter.

[0013] As a specific implementation of the estimation unit, it is conceivable that the estimation unit calculates a pre-estimated value indicating the state of the vaporizer by inputting the supply amount of the material, the output amount of the material gas, and the heater power consumption of the vaporizer into a vaporizer model that simulates the vaporizer, and then calculates a post-estimated value including an estimated value of the parameter related to the amount of the material based on the pre-estimated value and the value obtained by multiplying the deviation of the measured value corresponding to the pre-estimated value by the Kalman gain.

[0014] The estimated value calculated by the estimated value calculation unit may gradually deviate from the parameters relating to the actual amount of material. Therefore, it is desirable that the material vaporization system according to the present invention further comprises a material sensor for measuring the parameters relating to the amount of material in the vaporizer, the control device further comprises an estimated value correction unit for correcting the estimated value based on the measurement value obtained by the material sensor, and the supply amount control unit controls the supply amount adjustment device based on the estimated value corrected by the estimated value correction unit.

[0015] In order to accurately calculate the estimated values, it is desirable that the estimation unit calculates estimated values ​​of parameters related to the amount of material in the vaporizer based on the temperature of the vaporizer, the pressure of the vaporizer, the temperature of the material supplied to the vaporizer, or the pressure of the material supplied to the vaporizer, in addition to the supply amount of the material and the output amount of the material gas.

[0016] Furthermore, it is desirable that the material vaporization system according to the present invention includes a flow control valve that adjusts the flow rate of the material gas discharged from the vaporizer, a flow sensor that measures the flow rate of the material gas, a valve control unit that controls the flow control valve based on the flow rate measured by the flow sensor, and a deterioration estimation unit that inputs the estimated value and the applied voltage to the flow control valve to a valve model that simulates the flow control valve and estimates the deterioration of the flow control valve. With this configuration, the deterioration of the flow control valve can be estimated, so that maintenance or replacement of the flow control valve can be performed at an appropriate time.

[0017] Furthermore, the material vaporization method according to the present invention is a material vaporization method using a vaporizer that vaporizes a material to generate a material gas, and a supply amount adjustment device that adjusts the amount of material supplied to the vaporizer, characterized in that an estimated value of a parameter relating to the amount of material in the vaporizer is calculated based on the amount of material supplied to the vaporizer and the amount of material gas discharged from the vaporizer, and the supply amount adjustment device is controlled based on the estimated value.

[0018] In addition, the material vaporization program according to the present invention is used in a material vaporization system having a vaporizer that vaporizes a material to generate a material gas and a supply amount adjustment device that adjusts the amount of material supplied to the vaporizer, and is characterized in that it causes a computer to perform functions as an estimation value calculation unit that calculates estimated values ​​of parameters related to the amount of material in the vaporizer based on the amount of material supplied to the vaporizer and the amount of material gas discharged from the vaporizer, and as a supply amount control unit that controls the supply amount adjustment device based on the estimated values.

[0019] The material vaporization program may be distributed electronically, or it may be recorded on a program recording medium such as a CD, DVD, or flash memory.

[0020] According to the present invention configured in this manner, it is possible to accurately control parameters related to the amount of material while enabling stable flow rate control of the material gas.

[0021] This is a schematic diagram showing a material vaporization system according to the first embodiment of the present invention. This is a functional configuration diagram of the control device in the first embodiment. This is a control block diagram of liquid level control of a liquid material in the first embodiment. This is a graph showing the correction method for the estimated liquid level in the first embodiment. This is a graph showing the simulation results in the first embodiment. This is a diagram showing the vaporizer model (state-space model) in the second embodiment. This is a block diagram of the nonlinear Kalman filter in the second embodiment. This is a graph showing the experimental results in the second embodiment. This is a control block diagram of liquid level control of a liquid material and deterioration estimation of the flow control valve in a modified embodiment. This is a graph showing pressure fluctuations in the storage container in conventional liquid level control of a liquid material.

[0022] <First Embodiment> A first embodiment of the material vaporization system according to the present invention will be described below with reference to the drawings. In addition, all of the following figures are schematic representations that have been appropriately omitted or exaggerated for the sake of clarity. The same components are denoted by the same reference numerals and their descriptions are appropriately omitted.

[0023] The material vaporization system 100 of this embodiment is for supplying a predetermined flow rate of material gas to a chamber used in a semiconductor manufacturing process, for example, by being incorporated into a semiconductor manufacturing line.

[0024] Specifically, as shown in Figure 1, the material vaporization system 100 includes a vaporization unit 2 that vaporizes a liquid material, a mass flow controller 3 that controls the flow rate of the gas vaporized by the vaporization unit 2 (hereinafter referred to as material gas), and a control device 4 that controls the operation of the vaporization unit 2 and the mass flow controller 3.

[0025] The vaporization unit 2 includes a vaporizer 21 that vaporizes the liquid material, for example, by a baking method, and a supply amount adjustment device 22 that adjusts the amount of liquid material supplied to the vaporizer 21.

[0026] The vaporizer 21 and the supply rate adjustment device 22 are mounted on one side of the main body block B, which is a manifold block with flow paths formed inside. The main body block B is made of metal such as stainless steel and has a roughly rectangular parallelepiped shape with a longitudinal direction.

[0027] The vaporizer 21 includes a storage container 211 for storing liquid material and a heater 212 provided in the storage container 211 for vaporizing the liquid material. The storage container 211 is provided with a liquid level sensor 213 for detecting the amount of liquid material stored. This liquid level sensor is a material sensor that measures the liquid level as a parameter related to the amount of material. In this embodiment, the liquid level sensor 213 is, for example, inserted into the upper wall of the storage container 211 and is a float type that moves up and down in accordance with fluctuations in the liquid level of the liquid material. Various types of liquid level sensors can be used as the liquid level sensor 213, such as self-heating type, liquid temperature measuring type, magnetic type, capacitive type, or ultrasonic type.

[0028] The supply amount adjustment device 22 is an adjustment valve that adjusts the amount of liquid material supplied to the vaporizer 21, and in this embodiment, it is an electromagnetic valve. Specifically, the valve body of the electromagnetic valve 22 (not shown) is configured to open or close an internal flow path formed in the main body block B to supply or stop the supply of liquid material to the vaporizer 21.

[0029] In the vaporization unit 2 configured as described above, the electromagnetic valve 22, which is a supply amount adjustment device, is controlled to introduce liquid material from the liquid material introduction port P1 into the storage container 211, so that the liquid material is constantly stored in the storage container 211. Then, as the liquid material is vaporized in the storage container 211, material gas is continuously generated, and the material gas is continuously supplied to the mass flow controller 3.

[0030] Next, the mass flow controller 3 will be described. The mass flow controller 3 includes a fluid detection device 31 that detects the material gas flowing through the flow path and a flow control valve 32 that adjusts the flow rate of the material gas flowing through the flow path. The fluid detection device 31 consists of a first heat-generating resistor 311 provided on the upstream side of the flow path and a second heat-generating resistor 312 provided on the downstream side of the flow path. The flow control valve 32 adjusts the flow rate of the material gas generated by the vaporizer 21, and in this embodiment, it is a so-called normally open type piezo valve.

[0031] These fluid detection devices 31 and flow control valves 32 are mounted on one side of the main body block B, which has a flow path formed inside. Specifically, the fluid detection devices 31 and flow control valves 32 are mounted downstream of the vaporization unit 2 on the main body block B. This main body block B is installed in a semiconductor manufacturing line or the like so that its longitudinal direction is vertical, with the liquid material introduction port P1 located at the bottom and the vaporized gas outlet port P2 located at the top. The vaporization unit 2 and mass flow controller 3 mounted on the main body block B are housed in a casing (not shown).

[0032] Next, the control device 4 will be described. During vaporization operation, the control device 4 controls the electromagnetic on / off valve 22, which is a supply amount adjustment device, to supply liquid material to the vaporizer 21, and also controls the flow rate adjustment valve 32 of the mass flow controller 3 to adjust the flow rate of the material gas.

[0033] Specifically, the control device 4 is a so-called computer having a CPU, memory, AC / DC converter, input means, etc., and by executing the program stored in the memory with the CPU, it has functions such as a set flow rate receiving unit 41, a flow rate calculation unit 42, a valve control unit 43, an estimated value calculation unit 44, a supply amount control unit 45, and an estimated value correction unit 46, as shown in Figure 2.

[0034] The following describes each of the parts 41 to 46. The set flow rate receiving unit 41 receives, for example, user input operations via input means such as a keyboard, or a set flow rate signal indicating the set flow rate transmitted from another device.

[0035] The flow rate calculation unit 42 acquires the output signal from the fluid detection device 31 and calculates the flow rate of the material gas flowing through the internal flow path of the main block B. Here, the flow rate calculation unit 42 and the aforementioned fluid detection device 31 constitute a flow sensor for measuring the flow rate of the material gas, and the flow sensor in this embodiment is a thermal type. However, the flow sensor may also be a pressure type.

[0036] The valve control unit 43 controls the flow control valve 32 based on the set flow rate and the measured flow rate calculated by the flow rate calculation unit 42. Here, a drive signal is output to the flow control valve 32 so that the measured flow rate becomes the set flow rate, and the valve opening degree is controlled.

[0037] As shown in FIG. 3, the estimated value calculation unit 44 uses a vaporizer model 21M that simulates the vaporizer 21, and the liquid level height h as a parameter related to the amount of the liquid material in the storage container 211 in the vaporizer 21 ＥＳＴ is estimated.

[0038] Specifically, the estimated value calculation unit 44 inputs the supply amount Q of the liquid material supplied to the vaporizer 21 ｉｎ and the derived amount Q of the material gas derived from the vaporizer 21 ｏｕｔ into the vaporizer model 21M that simulates the vaporizer 21, and calculates the liquid level estimated value h of the vaporizer 21 ＥＳＴ

[0039] Here, the vaporizer model 21M that simulates the vaporizer 21 shows the relationship between the supply amount Q of the liquid material supplied to the storage container 211 ｉｎ and the derived amount Q of the material gas derived from the storage container 211 ｏｕｔ and the liquid level height h of the liquid material in the storage container 211 ＥＳＴ

[0040] Specifically, the vaporizer model 21M can be expressed using the following basic formula, and the liquid level estimated value h ＥＳＴ can be calculated. In the basic formula, the symbol V is the internal volume of the storage container 211.

[0041] Also, the supply amount Q of the liquid material supplied to the vaporizer 21 ｉｎ may be a directly measured value or an estimated value. Specifically, the supply amount Q of the liquid material ｉｎ ​​Examples of such values ​​include: (1) a value obtained by measuring the flow rate of the liquid material supplied to the vaporizer 21 using a flow sensor; (2) a value estimated from the time it takes for the liquid level sensor 213 to detect a predetermined liquid level and the volume (or cross-sectional area) of the storage container; (3) a value estimated from the supply pressure, supply temperature, and supply time of the liquid material; or (4) a value estimated from the opening degree of the electromagnetic valve 22 and the supply time, assuming that the supply pressure and supply temperature of the liquid material are constant.

[0042] Furthermore, the amount of material gas Q discharged from the vaporizer 21 ｏｕｔ The flow rate of the material gas calculated by the flow rate calculation unit 42 can be used. In addition, the amount of material gas discharged Q ｏｕｔ This can be calculated, for example, based on the evaporation rate of the liquid material determined by the Antoine formula.

[0043] Specifically, the estimation unit 44 calculates the supply amount Q of the liquid material to the vaporizer model 21M. ｉｎ and the amount of material gas discharged Q ｏｕｔ In addition, the temperature T of the vaporizer 21 ｔａｎｋ , and / or the pressure P of the vaporizer 21 ｖａｐ Enter the estimated liquid level h ＥＳＴ The temperature T of the vaporizer 21 is calculated. ｔａｎｋ This is the temperature of the storage container 211 or the heater 212, and the pressure P of the vaporizer 21. ｖａｐ This is the pressure of the material gas inside the storage container 211.

[0044] Furthermore, the estimation unit 44 may also input the temperature of the liquid material supplied to the vaporizer 21 and / or the pressure of the liquid material supplied to the vaporizer 21 to the vaporizer model 21M in addition to the above, and calculate the estimated liquid level.

[0045] The supply amount control unit 45 receives the estimated liquid level value h calculated by the estimated value calculation unit 44. ＥＳＴ Based on this, the supply amount adjustment device 22 is controlled. Specifically, the supply amount control unit 45 controls the estimated liquid level h ＥＳＴ The supply amount adjustment device 22 is controlled so that the liquid level estimate value h ＥＳＴ The liquid level setting value h is a constant value. ＳＥＴThe electromagnetic switching valve 22, which is a supply amount adjustment device, is controlled to turn on and off in such a manner.

[0046] The estimated value correction unit 46 calculates the liquid level measurement h obtained by the liquid level sensor 213. ｍｅａｓ Based on this, the estimated liquid level h ＥＳＴ This corrects the value. Specifically, as shown in Figure 4, the liquid level measurement h ｍｅａｓ When the liquid level reaches a predetermined lower limit, the estimated liquid level h ＥＳＴ set to a predetermined lower limit (liquid level measurement h ｍｅａｓ A correction is made to match the value, and the vaporizer model 21M is updated accordingly. Also, the liquid level measurement value h ｍｅａｓ When it reaches a predetermined upper limit, the estimated liquid level h ＥＳＴ set to a predetermined upper limit (liquid level measurement h ｍｅａｓ The system performs a correction to match the value, and accordingly updates the vaporizer model 21M. The supply control unit 45 then adjusts the liquid level estimate h corrected by the estimate correction unit 46. ＥＳＴ Based on this, the supply amount adjustment device 22 is controlled. The estimated value correction unit 46 uses the liquid level measurement value h ｍｅａｓ When the liquid level reaches a predetermined value, the estimated liquid level h ＥＳＴ In addition to a configuration that corrects the liquid level estimate h at a predetermined time after a certain period of time has elapsed. ＥＳＴ The liquid level measurement h ｍｅａｓ You may make corrections based on this.

[0047] Next, in the material vaporization system 100 of this embodiment, the estimated liquid level h in the storage container 211 ＥＳＴ Figure 5 shows the simulation results of pressure fluctuations inside the storage container 211 when the temperature is kept constant.

[0048] Figure 5(a) shows the estimated liquid level h, calculated using the vaporizer model 21M. ＥＳＴ This graph shows the change in the liquid level, and Figure 5(b) shows the estimated liquid level h. ＥＳＴ This graph shows the change in the supply amount of liquid material (ON / OFF of the electromagnetic valve) to keep the liquid level constant. Figure 5(c) shows the estimated liquid level h. ＥＳＴ This graph shows the change in pressure inside the storage container 211 when the temperature is kept constant.

[0049] Liquid level estimate h using a vaporizer model as in this embodiment ＥＳＴBy adjusting the supply amount of liquid material using this method, pressure fluctuations within the storage container 211 can be suppressed.

[0050] <Effects of the First Embodiment> According to the material vaporization system 100 of the first embodiment configured in this way, the supply amount Q of the liquid material supplied to the vaporizer 21 is supplied to the vaporizer model 21M which simulates the vaporizer 21. ｉｎ and the amount of material gas Q discharged from the vaporizer 21 ｏｕｔ Enter the following value to estimate the liquid level h of the vaporizer 21. ＥＳＴ Calculate the estimated liquid level h ＥＳＴ Since the supply adjustment device 22 is controlled based on this, the liquid level can be controlled with high precision. Furthermore, by controlling the liquid level with high precision, pressure fluctuations in the storage container 211 of the vaporizer 21 can be suppressed, thereby enabling stable flow rate control of the material gas in the mass flow controller 3.

[0051] <Second Embodiment> Next, a second embodiment of the material vaporization system according to the present invention will be described with reference to the drawings. In the second embodiment, components that are the same as or corresponding to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted as appropriate.

[0052] The material vaporization system 100 of the second embodiment differs from the material vaporization system 100 of the first embodiment in that the estimated value calculation unit 44 of the control device 4 is different. The estimated value calculation unit 44 of this embodiment will be described in detail below.

[0053] The estimation unit 44 of this embodiment uses the vaporizer model shown in Figure 6 to estimate the liquid level h as a parameter relating to the amount of liquid material in the storage container 211 in the vaporizer 21.

[0054] Specifically, the estimated value calculation unit 44 calculates the supply amount Q of the liquid material supplied to the vaporizer 21 in the vaporizer model 21M, which simulates the vaporizer 21. ｉｎ Q is the amount of material gas discharged from the vaporizer 21. ｏｕｔ and power consumption W of the heater 212 of the vaporizer 21 ｈｅａｔ Enter the following value to estimate the liquid level h of the vaporizer 21. ＥＳＴ Calculate.

[0055] In this vaporizer model 21M, the input vector u is the supply amount Q of the liquid material. ｉｎ (kg / s), amount of material gas discharged Q ｏｕｔ (SLM) and power consumption of heater 212 (W) ｈｅａｔ (W)

[0056] Furthermore, the state variable vector x is the number of moles (n) of material gas in the storage container 211 and the temperature T of the vaporizer 21. ｔａｎｋ (°C), temperature T of the liquid material in the storage container 211 ｌｉｑ (°C), h is the liquid level height of the liquid material in the storage container 211.

[0057] Furthermore, the output vector y is the pressure P of the material gas derived from the storage container 211. ｖａｐ (kPa) and the temperature T of the vaporizer 21 ｔａｎｋ It is (°C).

[0058] Here, the pressure P of the material gas ｖａｐ This can be calculated using the following formula.

[0059] The time evolution equations for this vaporizer model can be expressed by the following equations. Note that the following two equations are functions of the input vector x.

[0060] Here, the first derivative of the state variable (indicated by a todd symbol "•" above it) can be expressed by the following equation.

[0061] In matrix form, it can be expressed as follows:

[0062] In the above, the symbols are as follows: P ａｔｍ : Atmospheric pressure [kPa]. Ta: 273.15 [K]. R: Gas constant [J / (K·mol)]. m ｅｖａｐ : This is the evaporation rate of the liquid material [kg / s]. P ｓａｔ : Saturated vapor pressure [kPa] of the liquid material. v: Proportionality constant [m / s]. ΔP ｏｗ: The amount of heat input / output per unit time in a liquid material [W]. k: The proportionality constant [W / k]. a: The area of ​​the bottom surface of the storage container [m²] ２ ] is. V ｔｏｔ : Internal volume of the storage container [m³] ３ ]. ρ: Density of the liquid material [kg / m³] ３ ]. L: Latent heat of the liquid material [J / kg]. c: Specific heat of the liquid material [J / (kg·K)]. M ｍａｔｌ : This is the molar mass of the liquid material. α: This is the heat dissipation coefficient of the storage container [J / K·s]. C ｔａｎｋ : This is the heat capacity (J / K) of the storage container. ｉｎ : This is the temperature [°C] of the liquid material supplied to the storage container.

[0063] In the above, v, k, α, C ｔａｎｋ These are unknown parameters, but these parameters can be determined in advance by experimentation or simulation. For example, in one cycle of supplying liquid material to the storage container, the output vector y = (P ｇａｓ , T ｔａｎｋ ) so that v, k, α, C match the measured values ｔａｎｋ It can be tuned.

[0064] Then, as shown in Figure 6, the estimation unit 44 uses a nonlinear Kalman filter based on the vaporizer model described above to estimate the liquid level h of the vaporizer 21. ＥＳＴ Calculate (= h (hat)).

[0065] Specifically, the estimated value calculation unit 44 supplies the vaporizer model 21M with the supply amount Q. ｉｎ , derived quantity Q ｏｕｔ and power consumption (W) ｈｅａｔ The input is used to calculate a pre-estimated value indicating the state of the vaporizer 21. The pre-estimated value here is the state variable vector x (hat). － (i) and output vector y (hat) － (i) is included.

[0066] Furthermore, the estimation unit 44 calculates the deviation between the prior estimate and the measured value (observed value) corresponding to the prior estimate, and applies the Kalman gain G to that deviation.ＫＦ Multiply by (i).

[0067] Here, the prior estimated value for obtaining the deviation is the output vector y (hat) － The pressure P of the material gas included in (i) ｖａｐ and the temperature T of the vaporizer 21 ｔａｎｋ are. Also, the estimated value calculation unit 44 measures the actual system (vaporizer 21) for the pressure P ｖａｐ and the temperature T of the vaporizer 21 ｔａｎｋ to obtain the measured value of the pressure P ｖａｐ and the prior estimated value of the temperature T of the vaporizer 21 ｔａｎｋ and calculates the deviation between the prior estimated value of the pressure P ｖａｐ and the measured value of the temperature T of the vaporizer 21 ｔａｎｋ and the measured value. The pressure P of the material gas ｖａｐ can be measured by a pressure sensor provided in the flow path between the storage container 211 and the flow rate adjustment valve 32. Also, the temperature T of the vaporizer 21 ｔａｎｋ can be measured by a temperature sensor provided in the storage container 211.

[0068] Then, the estimated value calculation unit 44 adds the error multiplied by the Kalman gain G ＫＦ (i) and the prior estimated value x (hat) － (i) of the state variable vector to calculate the posterior estimated value x (hat) (i). This posterior estimated value x (hat) (i) includes the liquid level estimated value h (hat) (i), and the liquid level estimated value h (hat) (i) can be obtained. Note that, using the state variable vector x (hat) (i) which is the posterior estimated value, the output vector which is the posterior estimated value can also be calculated.

[0069] Next, FIG. 8 shows the experimental results when the liquid level of the storage container 211 is controlled to be constant using the liquid level estimated value h (hat) in the material vaporization system 100 of the present embodiment.

[0070] FIG. 8(a) is a graph showing the ON / OFF of the electromagnetic on-off valve and the discharge amount Q ｏｕｔ of the material gas in order to make the liquid level estimated value h (hat) constant. FIG. 8(b) is the measured value P ｖａｐ of the pressure P ｖａｐ(Measured) and the estimated value P ｖａｐ is a graph showing (Estimated). FIG. 8(c) shows the temperature T of the storage container 211 ｔａｎｋ of the measured value T ｔａｎｋ (Measured) and the estimated value T ｔａｎｋ (Estimated) and the estimated value T of the temperature T of the liquid material in the storage container 211 ｌｉｑ (Estimated). FIG. 8(d) is a graph showing the change in the pressure (secondary-side pressure) of the material gas derived from the material vaporization system 100. FIG. 8(e) is a graph showing the change in the liquid level estimated value h ｌｉｑ (Estimated). ＥＳＴ (Estimated).

[0071] By adjusting the supply amount of the liquid material using the liquid level estimated value h as in this embodiment, as shown in FIG. 8(b), the rapid pressure fluctuation in the storage container 211 can be suppressed. Also, as shown in FIG. 8(d), the pressure fluctuation of the material gas (secondary-side pressure) derived from the material vaporization system 100 can be suppressed. ＥＳＴ (Estimated).

[0072] <Effect of the Second Embodiment> According to the material vaporization system 100 of the second embodiment configured as described above, since the estimated value can be calculated with high accuracy, for example, the control of parameters related to the amount of the material such as the liquid level can be performed with high accuracy. And, for example, by accurately controlling the parameters related to the amount of the material such as the liquid level, the pressure fluctuation in the vaporizer can be suppressed, so that stable flow rate control of the material gas can be enabled.

[0073] <Other Embodiments> For example, the control device 4 of the material vaporization system 100 may be configured to estimate the deterioration of the flow rate adjustment valve 32 of the mass flow controller 3 using the liquid level estimated value h ＥＳＴ (Estimated). Specifically, as shown in FIG. 9, the control device 4 inputs the liquid level estimated value h ＥＳＴ and the applied voltage V of the flow rate adjustment valve 32 to a valve model 32M that simulates the flow rate adjustment valve 32 ｇｖThe configuration may also include a deterioration estimation unit 47 that takes the input of the liquid level estimate value h as an input and estimates the deterioration of the flow control valve 32. ＥＳＴ And the applied voltage V of the flow control valve 32 ｇｖ This shows the relationship with the internal resistance value of the flow control valve 32. This valve model 32M includes the temperature T of the flow control valve 32. ｍｆｃ This will also be entered.

[0074] Furthermore, the deterioration estimation unit 47 may be configured to output alarm signals in stages based on the estimated degree of deterioration of the flow control valve 32. For example, it is conceivable that a Caution signal would be output in the case of moderate deterioration, and an Alarm signal would be output in the case of severe deterioration.

[0075] In the above embodiment, the estimated value calculation unit 44 calculated an estimated value of the liquid level, which is a parameter related to the amount of material in the vaporizer 21. However, it may also calculate estimated values ​​of other parameters related to the amount of material, such as storage volume, volume, or weight.

[0076] Although the material vaporization system of the above embodiment vaporizes a liquid material, the material to be vaporized is not limited to a liquid, but may also be a solid such as a powder.

[0077] Although the vaporizer 21 in the above embodiment was of the baking type, it may also be of the bubbling type, in which a carrier gas is introduced into the material in the storage container and the material is vaporized by bubbling. In the case of this bubbling type, the estimation unit 44 calculates estimated values ​​of parameters related to the amount of material in the vaporizer based on the amount of carrier gas supplied to the vaporizer 21 and the amount of material gas (or a mixed gas of material gas and carrier gas) discharged from the vaporizer.

[0078] In the above embodiment, the supply amount adjustment device 22 was an on-off valve, but it may also be a control valve such as a piezo valve, or a mass flow controller equipped with such a control valve. In this case, the amount of liquid material supplied to the vaporizer 21 can be controlled by controlling the valve opening of the control valve using the estimated liquid level value.

[0079] Furthermore, in the above embodiment, the vaporization unit 2 and the mass flow controller 3 were mounted on the main body block B, which is a manifold block, but the vaporization unit 2 and the mass flow controller 3 may be fluidically connected via pipe fittings or the like. Also, in the vaporization unit 2, the vaporizer 21 and the supply amount adjustment device 22 may be fluidically connected via pipe fittings or the like, and in the mass flow controller 3, the fluid detection device 31 and the flow control valve may be fluidically connected via pipe fittings or the like.

[0080] Furthermore, modifications and combinations of each embodiment are permitted, as long as they do not contradict the spirit of the present invention.

[0081] According to the present invention, it is possible to accurately control parameters related to the amount of material while enabling stable flow rate control of the material gas.

[0082] 100...Material vaporization system 21...Vaporizer 213...Liquid level sensor (material sensor) 22...Supply amount adjustment device 31...Fluid detection device (flow sensor) 32...Flow control valve 4...Control device 42...Flow rate calculation unit (flow sensor) 43...Valve control unit 44...Estimated value calculation unit 45...Supply amount control unit 46...Estimated value correction unit 47...Degradation estimation unit

Claims

1. A material vaporization system comprising: a vaporizer that vaporizes a material to generate a material gas; a supply amount adjustment device that adjusts the amount of material supplied to the vaporizer; and a control device that controls the supply amount adjustment device, wherein the control device includes: an estimation value calculation unit that calculates estimated values ​​of parameters relating to the amount of material in the vaporizer based on the amount of material supplied to the vaporizer and the amount of material gas discharged from the vaporizer; and a supply amount control unit that controls the supply amount adjustment device based on the estimated values.

2. The material vaporization system according to claim 1, wherein the estimated value calculation unit calculates an estimated value of a parameter relating to the amount of material based on the supply amount of the material and the output amount of the material gas, using a vaporizer model that simulates the vaporizer.

3. The material vaporization system according to claim 2, wherein the estimated value calculation unit calculates an estimated value of a parameter relating to the amount of material based on the supply amount of the material and the output amount of the material gas, as well as the heater power consumption of the vaporizer.

4. The material vaporization system according to claim 2 or 3, wherein the estimated value calculation unit uses a nonlinear Kalman filter.

5. The material vaporization system according to claim 4, wherein the estimation unit inputs the supply amount of the material, the output amount of the material gas, and the heater power consumption of the vaporizer into a vaporizer model that simulates the vaporizer and calculates a prior estimation value indicating the state of the vaporizer, and calculates a post-estimation value including an estimation value of a parameter related to the amount of the material based on the prior estimation value and the value obtained by multiplying the deviation of the measured value corresponding to the prior estimation value by the Kalman gain.

6. The material vaporization system according to claim 1, further comprising a material sensor for measuring parameters relating to the amount of material in the vaporizer, the control device further comprising an estimated value correction unit for correcting the estimated value based on the measurement value obtained by the material sensor, and the supply amount control unit for controlling the supply amount adjustment device based on the estimated value corrected by the estimated value correction unit.

7. The material vaporization system according to claim 1 or 6, wherein the estimated value calculation unit calculates an estimated value of a parameter relating to the amount of material in the vaporizer based on the temperature of the vaporizer, the pressure of the vaporizer, the temperature of the material supplied to the vaporizer, or the pressure of the material supplied to the vaporizer, in addition to the supply amount of the material and the discharge amount of the material gas.

8. A material vaporization system according to any one of claims 1 to 7, comprising: a flow control valve for adjusting the flow rate of the material gas discharged from the vaporizer; a flow sensor for measuring the flow rate of the material gas; a valve control unit for controlling the flow control valve based on the flow rate measured by the flow sensor; and a deterioration estimation unit for estimating the deterioration of the flow control valve by inputting the estimated value and the applied voltage to the flow control valve to a valve model that simulates the flow control valve.

9. A material vaporization method using a vaporizer that vaporizes a material to generate a material gas, and a supply amount adjustment device that adjusts the amount of material supplied to the vaporizer, wherein an estimated value of a parameter relating to the amount of material in the vaporizer is calculated based on the amount of material supplied to the vaporizer and the amount of material gas discharged from the vaporizer, and the supply amount adjustment device is controlled based on the estimated value.

10. A material vaporization program used in a material vaporization system having a vaporizer that vaporizes a material to generate a material gas, and a supply amount adjustment device that adjusts the amount of material supplied to the vaporizer, wherein the program causes a computer to perform the following functions: an estimation value calculation unit that calculates estimated values ​​of parameters related to the amount of material in the vaporizer based on the amount of material supplied to the vaporizer and the amount of material gas discharged from the vaporizer, and a supply amount control unit that controls the supply amount adjustment device based on the estimated values.

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