Concentration control device, gas control system, film forming device and concentration control method

Abstract

A concentration control device, a gas control system, a film forming device, a concentration control method and a program recording medium for the concentration control device are provided. In a concentration control device for intermittently outputting a material gas from a vaporizer, in order to control the flow rate of a carrier gas and a dilution gas to suppress overshoot of the material gas concentration shortly after the start of the material gas supply period, the device comprises: a set flow rate calculation unit (33) for calculating an initial set flow rate of the flow rate control device (40) in an initial interval from the start to the second predetermined time in a second supply period after the first supply period based on an actual concentration calculated by a concentration calculation unit (32) at a first predetermined time in a first supply period for supplying the material gas, an actual flow rate output from a flow rate control device (40) at the first predetermined time in the first supply period, or a set flow rate of the flow rate control device (40) at the first predetermined time in the first supply period, and a preset target concentration.

Description

Technical Field

[0001] The present invention relates to a concentration control device, a gas control system, a film forming device, a concentration control method, and a program recording medium for a concentration control device used in, for example, a semiconductor manufacturing process. Background Art

[0002] Conventionally, as a device for controlling gas concentration used in semiconductor manufacturing processes and the like, there is a concentration control device used together with a vaporizer for vaporizing a liquid or solid material, as shown in Patent Document 1.

[0003] The vaporization device intermittently supplies a carrier gas to a vaporization tank storing a liquid or solid material, thereby intermittently extracting a material gas obtained by vaporizing the material from the vaporization tank, and supplies a mixed gas obtained by mixing the extracted material gas with a diluent gas to, for example, a chamber used in a semiconductor manufacturing process. With the above configuration, a supply period of the mixed gas and a stop period of stopping the supply are repeated, and the concentration control device performs feedback control by controlling the flow rate of the carrier gas and / or the diluent gas during the supply period, so that the concentration of the material gas contained in the mixed gas is close to a preset target concentration.

[0004] However, in the above configuration, since the supply period and the stop period are repeated, there is a problem that the material gas concentration in the vaporizer gradually increases during the stop period, and the material gas concentration in the mixed gas overshoots soon after the supply period starts.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2014-224307 Summary of the invention

[0008] Technical issues

[0009] Therefore, the present invention has been made to solve the above-mentioned problems, and a main object of the present invention is to control the flow rate of the carrier gas and / or the dilution gas so as to suppress the overshoot of the material gas concentration immediately after the start of the supply period.

[0010] Technical Solution

[0011] That is, the concentration control device of the present invention is used for a vaporization device, and the above-mentioned vaporization device comprises: a vaporization tank for storing liquid or solid materials; a carrier gas supply path for supplying carrier gas to the above-mentioned vaporization tank; a material gas outlet path through which the material gas discharged from the above-mentioned vaporization tank flows when the above-mentioned material is vaporized; a dilution gas supply path that merges with the above-mentioned material gas outlet path and supplies dilution gas to the material gas outlet path; a flow control device arranged on at least one of the above-mentioned carrier gas supply path and the above-mentioned dilution gas supply path; and a concentration monitor arranged on the above-mentioned material gas outlet path at a position closer to the downstream side than the confluence point with the above-mentioned dilution gas supply path, and the above-mentioned vaporization device repeats the supply and stop of the above-mentioned material gas.

[0012] Furthermore, the concentration control device is characterized in that it comprises: a concentration calculation unit, which calculates the concentration of the above-mentioned material gas based on the output signal from the above-mentioned concentration monitor; and a set flow calculation unit, which calculates the initial set flow of the above-mentioned flow control device in an initial interval as a period from the beginning to the second predetermined time within a supply period (hereinafter referred to as the second supply period) after the above-mentioned first supply period based on the actual concentration calculated by the above-mentioned concentration calculation unit at the first predetermined time within the supply period of the above-mentioned material gas (hereinafter referred to as the first supply period), the actual flow output from the above-mentioned flow control device at the first predetermined time within the first supply period or the set flow of the above-mentioned flow control device at the first predetermined time within the first supply period, and a pre-set target concentration.

[0013] If the concentration control device is constructed in this way, then since the initial set flow rate calculated based on the actual concentration calculated at the first scheduled time during the first supply period, the actual flow rate output from the flow control device at the first scheduled time during the first supply period, the set flow rate of the flow control device at the first scheduled time during the first supply period, and the pre-set target concentration can be set to the flow control device in the initial interval of the second supply period, overshoot shortly after the start of the second supply period can be reduced.

[0014] In order to more reliably reduce the overshoot immediately after the start of the second supply period, it is preferred that the concentration control device controls the flow rate flowing through the flow control device to the initial set flow rate in the initial section of the second supply period.

[0015] Preferably, after an initial section of the second supply period has elapsed, feedback control is performed by controlling a set flow rate of the flow control device so that the actual concentration calculated by the concentration calculation unit approaches the target concentration.

[0016] With such a configuration, control can be stabilized even after the initial section of the second supply period has passed.

[0017] As a specific implementation, the following method can be cited: the above-mentioned set flow calculation unit multiplies the ratio of the above-mentioned target concentration to the actual concentration calculated by the above-mentioned concentration calculation unit at the first predetermined time in the initial interval of the above-mentioned first supply period by the actual flow output from the above-mentioned flow control device at the first predetermined time in the initial interval of the above-mentioned first supply period, so as to calculate the above-mentioned initial set flow in the initial interval of the above-mentioned second supply period.

[0018] In addition, as other embodiments, the following method can be cited, wherein the above-mentioned concentration control device also has a flow rate-concentration relationship data storage unit for storing flow rate-concentration relationship data, and the flow rate-concentration relationship data represents the relationship between the flow rate of the above-mentioned carrier gas or the flow rate of the above-mentioned dilution gas and the concentration of the above-mentioned material gas flowing at a position closer to the downstream side of the confluence point of the above-mentioned material gas derivation path and the above-mentioned dilution gas supply path, and the above-mentioned set flow rate calculation unit uses the above-mentioned flow rate-concentration relationship data to calculate the above-mentioned initial set flow rate in the initial interval of the above-mentioned second supply period.

[0019] Preferably, the set flow rate calculation unit calculates an average initial set flow rate, and the average initial set flow rate is obtained by averaging initial set flow rates calculated for each of the plurality of supply periods in which the material gas has been supplied.

[0020] By setting the average initial setting flow rate to the flow control device, it is possible to reduce the error of each calculated initial setting flow rate, and to more reliably reduce the overshoot immediately after the start of the second supply period.

[0021] When the relationship between the flow rate and the concentration does not agree with the calculation formula of the initial set flow rate, there may be a case where the increase and decrease of the initial concentration in the continuous supply period are repeated alternately.

[0022] Therefore, it is preferable that the average initial set flow rate is obtained by averaging the initial set flow rates calculated by the set flow rate calculation unit for each of the continuous even-numbered supply periods.

[0023] According to such a configuration, since the estimated flow rates of consecutive even numbers are averaged, the increase and decrease in the initial concentration can be offset.

[0024] In addition, the gas control system of the present invention is characterized in that it comprises: a vaporization device, which comprises: a vaporization tank for storing liquid or solid materials; a carrier gas supply path for supplying carrier gas to the above-mentioned vaporization tank; a material gas outlet path through which the material gas that is vaporized and outlet from the above-mentioned vaporization tank flows; a dilution gas supply path that merges with the above-mentioned material gas outlet path and supplies dilution gas to the material gas outlet path; a flow control device provided in at least one of the above-mentioned carrier gas supply path and the above-mentioned dilution gas supply path; and a concentration monitor provided in the above-mentioned material gas outlet path at a position closer to the downstream side than the confluence point with the above-mentioned dilution gas supply path, wherein the above-mentioned vaporization device repeatedly supplies and stops the above-mentioned material gas; concentration A calculation unit that calculates the concentration of the material gas based on an output signal from the concentration monitor; and a set flow calculation unit that calculates an initial set flow of the flow control device in an initial interval from the beginning to a second predetermined time in a supply period after the first supply period (hereinafter referred to as a second supply period) based on an initial concentration calculated by the concentration calculation unit at a first predetermined time in a supply period of the material gas (hereinafter referred to as a first supply period), an actual flow output from the flow control device at a first predetermined time in the first supply period or a set flow of the flow control device at a first predetermined time in the first supply period, and a pre-set target concentration.

[0025] A film forming apparatus including the above-mentioned gas control system and a chamber to which the above-mentioned material gas is supplied is also one of the present invention.

[0026] The concentration control method of the present invention is characterized in that it is used for a vaporization device, and the above-mentioned vaporization device includes: a vaporization tank for storing liquid or solid materials; a carrier gas supply path for supplying carrier gas to the above-mentioned vaporization tank; a material gas outlet path through which the material gas that is vaporized and outlet from the above-mentioned vaporization tank flows; a dilution gas supply path that merges with the above-mentioned material gas outlet path and supplies dilution gas to the material gas outlet path; a flow control device arranged in at least one of the above-mentioned carrier gas supply path and the above-mentioned dilution gas supply path; and a concentration monitor arranged in the above-mentioned material gas outlet path at a position closer to the downstream side than the confluence point with the above-mentioned dilution gas supply path, and the above-mentioned vaporization device repeats the supply and Stop, the above-mentioned concentration control method includes: a step of calculating the concentration of the above-mentioned material gas based on the output signal from the above-mentioned concentration monitor; a step of calculating the initial set flow rate of the above-mentioned flow control device in an initial interval as a period from the beginning to the second predetermined time within a supply period (hereinafter referred to as the second supply period) after the above-mentioned first supply period based on the initial concentration calculated at the first predetermined time within the supply period of the above-mentioned material gas (hereinafter referred to as the first supply period), the actual flow rate output from the above-mentioned flow control device at the first predetermined time within the first supply period or the set flow rate of the above-mentioned flow control device at the first predetermined time within the first supply period, and a pre-set target concentration.

[0027] The program recording medium for a concentration control device of the present invention is characterized in that it records a program for a concentration control device for a vaporization device, wherein the vaporization device comprises: a vaporization tank for storing liquid or solid materials, a carrier gas supply path for supplying carrier gas to the vaporization tank, a material gas outlet path through which the material gas discharged from the vaporization tank flows when the material is vaporized, a dilution gas supply path that merges with the material gas outlet path and supplies dilution gas to the material gas outlet path, a flow control device arranged in at least one of the carrier gas supply path and the dilution gas supply path, and a concentration monitor arranged in the material gas outlet path at a position closer to the downstream side than the confluence point with the dilution gas supply path, the vaporization device repeatedly supplies and stops the material gas, and the concentration control device program The sequence recording medium enables the computer to function as a concentration calculation unit and a set flow calculation unit, the concentration calculation unit calculates the concentration of the material gas based on the output signal from the concentration monitor; the set flow calculation unit calculates the initial set flow of the flow control device in an initial interval as a period from the beginning to the second predetermined time within a supply period (hereinafter referred to as the second supply period) after the first supply period based on the initial concentration calculated by the concentration calculation unit at the first predetermined time within the supply period of the material gas (hereinafter referred to as the first supply period), the actual flow output from the flow control device at the first predetermined time within the first supply period or the set flow of the flow control device at the first predetermined time within the first supply period, and the pre-set target concentration.

[0028] Such a gas control system, film forming apparatus, concentration control method, and concentration control apparatus program can exert the same effects as those of the above-mentioned concentration control apparatus.

[0029] Effects of the Invention

[0030] According to the present invention thus constituted, in a configuration in which the material gas is intermittently supplied, the flow rates of the carrier gas and / or the dilution gas can be controlled so as to suppress overshoot of the material gas concentration immediately after the start of the supply period. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a diagram schematically showing the overall configuration of the gas control system according to the present embodiment.

[0032] Figure 2 It is a diagram showing the intermittent flow of the material gas in the gas control system of this embodiment.

[0033] Figure 3 It is a functional block diagram showing the functions of the concentration control device according to this embodiment.

[0034] Figure 4 It is a diagram for explaining the calculation method of the initial setting flow rate in this embodiment.

[0035] Figure 5 It is a flowchart showing the operation of the concentration control device of this embodiment.

[0036] Explanation of symbols

[0037] 100: Gas control system

[0038] 10: Vaporizer

[0039] L1: Carrier gas supply path

[0040] L2: Material gas extraction path

[0041] L3: Dilution gas supply path

[0042] 30: Concentration control device

[0043] 31: Target concentration receiving unit

[0044] 32: Concentration calculation unit

[0045] 33: Set the flow calculation unit

[0046] 50: Concentration monitor DETAILED DESCRIPTION

[0047] Hereinafter, one embodiment of the concentration control device of the present invention will be described with reference to the drawings.

[0048] The gas control system 100 of this embodiment is used to supply a gas of a predetermined concentration to a chamber CH used in a semiconductor manufacturing process, for example, which is incorporated in a semiconductor production line, etc. The gas control system 100 and the chamber CH together constitute a film forming apparatus used in semiconductor manufacturing, etc.

[0049] Specifically, if Figure 1 As shown, the gas control system 100 comprises: a vaporizer 10 for storing liquid or solid materials; a carrier gas supply path L1 for supplying a carrier gas to the vaporizer 10; a material gas outlet path L2 for outleting a material gas obtained by vaporizing the material from the vaporizer 10; a dilution gas supply path L3 for supplying a dilution gas for diluting the material gas to the material gas outlet path L2; a switching mechanism 20 for switching the supply of the material gas to the chamber CH and stopping it; and a concentration control device 30 for controlling the concentration of the material gas supplied to the chamber CH.

[0050] The carrier gas supply path L1 is provided with a first flow control device 40 for controlling the flow rate of the carrier gas. The first flow control device 40 is a mass flow controller including, for example, a thermal flow sensor, a flow control valve such as a piezoelectric valve, and a control circuit having a CPU and / or a memory.

[0051] A concentration monitor 50 for measuring the concentration of the material gas contained in the mixed gas is provided in the material gas outlet path L2. The concentration monitor 50 of this embodiment uses the ratio of the pressure (partial pressure) of the material gas contained in the mixed gas to the pressure (total pressure) of the mixed gas to express the concentration (vol%) of the material gas contained in the mixed gas. Specifically, the concentration monitor 50 includes a pressure gauge 51 for measuring the total pressure and a pressure gauge 52 for measuring the partial pressure, for example, using a non-dispersive infrared absorption method.

[0052] The dilution gas supply path L3 is connected to the upstream side of the concentration monitor 50 in the material gas outlet path L2, and is provided with a second flow control device 60 for controlling the flow rate of the dilution gas. The second flow control device 60 is a mass flow controller having, for example, a thermal flow sensor, a flow control valve such as a piezoelectric valve, and a control circuit having a CPU and / or a memory, similarly to the first flow control device 40.

[0053] The switching mechanism 20 includes a plurality of valves V1 to V3 that are opened and closed by receiving a valve switching signal. By opening and closing these valves V1 to V3 at a timing preset by a user, for example, the supply and stop of the carrier gas to the vaporizer 10 are repeated. Figure 2 As shown, the material gas is intermittently discharged from the vaporizer 10 and intermittently supplied to the chamber CH. That is, in the gas control system 100 of this embodiment, a supply period of the material gas (specifically, a mixed gas obtained by mixing the material gas and the dilution gas) to the chamber CH and a stop period of stopping the supply are repeated.

[0054] The switching mechanism 20 here comprises: a detour flow path L4 connecting the carrier gas supply path L1 and the material gas outlet path L2; a first valve V1 arranged in the carrier gas supply path L1 at a position closer to the downstream side than the connection position with the detour flow path L4; a second valve V2 arranged in the material gas outlet path L2 at a position closer to the upstream side than the connection position with the detour flow path L4; and a third valve V3 arranged in the detour flow path L4.

[0055] The first valve V1 and the second valve V2 are opened and the third valve V3 is closed to form a supply period, and the first valve V1 and the second valve V2 are closed and the third valve V3 is opened to form a stop period.

[0056] The concentration control device 30 controls the concentration of the material gas supplied to the chamber CH by controlling the flow rate of the carrier gas and / or the dilution gas.

[0057] Specifically, the concentration control device 30 is a computer having a CPU, a memory, an AC / DC converter, an input unit, etc., and the CPU executes a program stored in the memory, thereby Figure 3 As shown, it has functions as a target concentration receiving unit 31, a concentration calculating unit 32, and a set flow rate calculating unit 33.

[0058] The target concentration receiving unit 31 receives, for example, a user's input operation using an input unit such as a keyboard and / or a target concentration signal indicating a target concentration transmitted from another device.

[0059] The concentration calculation unit 32 calculates the concentration of the material gas contained in the mixed gas (hereinafter also referred to as the actual concentration) based on the output signal output from the concentration monitor 50. Specifically, the output signals are obtained from the pressure gauge 51 and the partial pressure gauge 52, respectively, and the ratio of the partial pressure detected by the partial pressure gauge 52 to the total pressure detected by the pressure gauge 51 is calculated as the actual concentration (vol%) of the material gas contained in the mixed gas.

[0060] The set flow calculation unit 33 obtains the actual concentration signal output from the concentration calculation unit 32 and the target concentration signal received by the target concentration receiving unit 31, and calculates the set flow (hereinafter referred to as FB set flow) used for feedback control of the first flow control device 40 so that the actual concentration is close to the target concentration.

[0061] Furthermore, in this embodiment, if Figure 4 As shown, the set flow calculation unit 33 is constructed to calculate the initial set flow Q2 of the first flow control device 40 in the initial interval of the supply period (hereinafter referred to as the second supply period) after the first supply period based on the target concentration Cg received by the target concentration receiving unit 31, the actual concentration C1 calculated by the concentration calculation unit 32 at a predetermined time in the initial interval of the supply period of the supply material gas (hereinafter referred to as the first supply period), and the actual flow Q1 of the carrier gas output from the first flow control device 40 at a predetermined time in the initial interval of the first supply period.

[0062] Here, the "initial interval of the first supply period" refers to the period from the start of the first supply period to the first scheduled time after the first predetermined time T1 has passed. The first scheduled time is set to the time when the peak of the actual concentration first appears in the first supply period or before and after the time, and here, it is set to the time until the initial peak of the actual concentration drops completely.

[0063] In addition, the "initial interval of the second supply period" refers to the period from the start of the second supply period to the second scheduled time after the second scheduled time T2 set in advance, and here, the second scheduled time T2 is set to the same time as the first scheduled time T1. In other words, the second scheduled time is set to the time when the peak of the actual concentration first appears in the second supply period or before and after the time, and here, it is set to the time until the initial peak of the actual concentration drops completely.

[0064] Specifically, the flow calculation unit 33 is set to obtain the actual concentration C1 calculated by the concentration calculation unit 32 at the first predetermined time within the initial interval of the first supply period and the actual flow rate Q1 of the carrier gas calculated by the CPU of the first flow control device at the first predetermined time within the initial interval of the first supply period, and use a predetermined calculation formula to calculate the initial set flow rate Q2 of the second supply period.

[0065] In this embodiment, assuming that the concentration of the material gas contained in the mixed gas is proportional to the flow rate of the carrier gas, the set flow rate calculation unit 33 calculates the initial set flow rate Q2 for the second supply period immediately following the first supply period using the following calculation formula.

[0066] Initial set flow rate Q2 = actual flow rate Q1 × (target concentration Cg / actual concentration C1)

[0067] The set flow rate calculation unit 33 of this embodiment outputs the initial set flow rate calculated by the above calculation formula to the first flow control device 40 in the initial interval of the second supply period. On the other hand, after the initial interval of the second supply period has passed, the above FB set flow rate is output to the first flow control device 40.

[0068] In this embodiment, as described above, the total flow rate of the carrier gas flow rate and the dilution gas flow rate is controlled to be constant, and the set flow calculation unit 33 subtracts the set flow rate output to the first flow control device 40 from the predetermined total flow rate, and calculates and outputs the set flow rate of the second flow control device 60.

[0069] Next, refer to Figure 5 The flow chart of the present embodiment describes the operation of the concentration control device 30. It should be noted that in the following operation description, for convenience, the first supply period and the second supply period are referred to as supply periods, and the first scheduled time and the second scheduled time are referred to as scheduled times because they are set to the same time.

[0070] First, when the operation of the gas control system 100 starts, the concentration control device 30 determines whether it is in the supply period. Here, the flow rate calculation unit 33 is set to obtain a valve switching signal and determine whether it is in the supply period based on the signal (S1).

[0071] If it is determined in S1 that the supply period is not in progress, that is, in the stop period, the set flow rate calculation unit 33 sets the flow rates of the first flow control device 40 and the second flow control device 60 to the initial set flow rates calculated in S5 described later, and maintains the initial set flow rates (S2). It should be noted that during the stop period from the start of the operation of the gas control system 100 to the start of the initial supply period, the output of the set flow rates pre-set by the user to the first flow control device 40 and the second flow control device 60 is maintained.

[0072] On the other hand, when it is determined in S1 that the supply period is in progress, the set flow rate calculation unit 33 determines whether it is after a predetermined time (S3).

[0073] If it is determined in S3 that it is not after the predetermined time, that is, in the initial interval of the supply period, the set flow calculation unit 33 maintains the set flow set in the first flow control device 40, that is, the output of the initial set flow (S2), regardless of the actual concentration.

[0074] If it is determined in S3 that it is after the predetermined time, the set flow rate calculation unit 33 determines whether it is the predetermined time (S4).

[0075] If it is determined in S4 that it is the predetermined time, the set flow rate calculation unit 33 calculates the initial set flow rate for the next supply period (S5). The detailed calculation method is as described above.

[0076] On the other hand, if it is determined in S4 that it is not the predetermined time, the above-mentioned initial set flow rate calculation is not performed, and the set flow rate calculation unit 33 outputs the FB set flow rate to the first flow rate control device 40 to perform feedback control on the concentration of the material gas (S6).

[0077] It should be noted that in S2 and / or S6, the set flow rate calculation unit 33 calculates and outputs the set flow rate of the second flow rate control device 60 by subtracting the set flow rate output to the first flow rate control device 40 from the predetermined total flow rate.

[0078] Thereafter, it is determined whether a control end signal from the concentration control device 30 is received (S7), and S1 to S7 are repeated until the control end signal is received. If the control end signal is received, the operation is terminated.

[0079] According to the gas control system 100 of this embodiment configured as above, Figure 4 As shown, since the set flow calculation unit 33 calculates the initial set flow Q2 of the second supply period based on the target concentration Cg, the actual flow Q1 at the first predetermined moment in the initial interval of the first supply period, and the actual concentration C1 at the first predetermined moment in the initial interval of the first supply period, and outputs the initial set flow Q2 to the first flow control device in the initial interval of the second supply period, the initial concentration C2 of the second supply period can be made close to the target concentration Cg, and the overshoot shortly after the start of the second supply period can be suppressed.

[0080] It should be noted that the present invention is not limited to the above-mentioned embodiments.

[0081] For example, the set flow calculation unit 33 of the above embodiment calculates the initial set flow of the first flow control device 40 in the second supply period, but it is also possible to calculate the initial set flow of the second flow control device 60 in the second supply period. Specifically, the following configuration can be cited: the initial set flow of the second flow control device 60 in the initial interval of the second supply period is calculated based on the target concentration, the actual concentration calculated by the concentration calculation unit 32 at a predetermined time in the initial interval of the first supply period, and the actual flow of the dilution gas output from the second flow control device 60 at a predetermined time in the initial interval of the first supply period.

[0082] In this case, the initial set flow rate of the first flow control device may be a flow rate obtained by subtracting the initial set flow rate of the second flow control device from the predetermined total flow rate.

[0083] In addition, the calculation of the initial set flow rate Q2 during the second supply period is not limited to the calculation formula of the above embodiment. For example, the initial set flow rate Q1' of the first flow control device 40 at a predetermined time in the initial interval of the first supply period can be used instead of the actual flow rate Q1 and calculated using the following calculation formula.

[0084] Initial set flow rate Q2 = Initial set flow rate Q1' × (target concentration Cg / actual concentration C1)

[0085] In addition, the calculation formula of the initial setting flow rate Q2 is not limited to the above-mentioned embodiment.

[0086] For example, the following method can be cited: the concentration control device 30 also has a flow rate-concentration relationship data storage unit that stores flow rate-concentration relationship data, and the flow rate-concentration relationship data represents the relationship between the flow rate of the carrier gas or the dilution gas and the ratio in the material gas derivation path and the concentration of the material gas flowing at a position close to the downstream side of the confluence point of the dilution gas supply path, and the set flow calculation unit 33 uses the flow rate-concentration relationship data to calculate the initial set flow rate during the second supply period.

[0087] The flow-concentration relationship data may be, for example, a calculation formula applicable when the concentration of the material gas contained in the mixed gas is not proportional to the flow rate of the carrier gas and / or the flow rate of the dilution gas, which is different from the above-mentioned embodiment, for example, a nonlinear calculation formula.

[0088] By using such flow rate-concentration relationship data, even when the concentration of the material gas contained in the mixed gas is not proportional to the flow rate of the carrier gas and / or the flow rate of the dilution gas, the initial set flow rate in the second supply period can be calculated with high accuracy.

[0089] The calculation time of the initial set flow rate by the set flow rate calculation unit 33 is not limited to the predetermined time in the above embodiment. For example, the actual concentration C1 and / or the actual flow rate Q1 at the predetermined time may be temporarily stored in a memory and calculated after the predetermined time has passed.

[0090] In the above-mentioned embodiment, although it is configured to output the initial set flow rate in the subsequent second supply period at the end of the first supply period, the output timing is not limited to this. For example, it can also be any time in the stop period from the first supply period to the subsequent second supply period. As long as the overshoot can be reduced, it can also be, for example, shortly after the start of the second supply period.

[0091] The set flow rate calculation unit 33 may be configured to calculate an average initial set flow rate obtained by averaging initial set flow rates calculated for each of a plurality of supply periods during which the material gas has been supplied.

[0092] According to this configuration, by setting the average initial set flow rate to the flow control device in the initial section of the supply period, it is possible to reduce the error of each calculated initial set flow rate, and to more reliably reduce the overshoot in the initial section of the supply period.

[0093] In addition, when the relationship between the flow rate and the concentration does not agree with the calculation formula of the initial set flow rate, there may be a case where the increase and decrease of the initial concentration in the continuous supply period are repeated alternately.

[0094] Therefore, the set flow rate calculation unit 33 preferably calculates the average initial set flow rate by averaging the initial set flow rates calculated for each of the continuous even-numbered supply periods including the supply period immediately before the supply period for which the initial set flow rate is to be set.

[0095] According to such a configuration, since the increase and decrease in the initial concentration in the continuous supply period are averaged and offset, the initial set flow rate for bringing the actual concentration closer to the target concentration can be set with higher accuracy.

[0096] In the concentration control device 30 of the above embodiment, the set flow rate calculation unit 33 is configured to calculate and output both the FB set flow rate and the initial set flow rate. However, the concentration control device may also have a function of calculating the FB set flow rate and a function of calculating the initial set flow rate.

[0097] In addition, as the set flow rate calculation unit 33, for example, when the actual concentration in the initial interval of the first supply period exceeds a preset threshold, the initial set flow rate for the second supply period can be calculated based on the actual concentration (threshold) at that time and the actual flow rate at that time. In this case, the time when the actual concentration exceeds the threshold is the predetermined time.

[0098] The first flow control device 40 and / or the second flow control device 60 may also be a mass flow controller having a differential pressure flow sensor.

[0099] In addition, instead of using a mass flow controller, a fluid control valve such as a piezoelectric valve may be used as the first flow control device 40 and / or the second flow control device 60 .

[0100] The concentration monitor 50 may be a device that directly measures the concentration of the material gas using, for example, ultrasonic waves, etc. Alternatively, the concentration monitor 50 may function as the concentration calculator 32 and output the concentration from the concentration monitor 50 to the concentration controller 30 .

[0101] Although the gas control system of the bubbling method (bubbling method) has been described, the control method may be basically any control method as long as it is a control method using a carrier gas. For example, the gas control system 100 may be a system that does not have the second flow control device 60. In this case, the gas control system 100 may, for example, be a system that is configured to have a valve such as a piezoelectric valve downstream of the concentration monitor 50 in the material gas outlet path L2, and to control the opening of the valve to control the pressure of the material gas supply. In addition, it can also be applied to a method of transporting materials in a liquid state and vaporizing the materials near the place of use (for example, a film forming chamber) to control the flow rate, namely a DLI method (direct vaporization method).

[0102] The concentration control device of the above embodiment is a device for suppressing overshoot of the material gas concentration shortly after the start of the supply period, but the concentration control device of the present invention may be a device for suppressing undershoot of the material gas concentration shortly after the start of the supply period.

[0103] In addition, the present invention is not limited to the above-mentioned embodiment, and it is obvious that various modifications can be made without departing from the scope of the present invention.

Claims

1. A concentration control device, characterized in that: Used in a vaporization device, the vaporization device comprises: a vaporization tank for storing liquid or solid materials; a carrier gas supply path for supplying carrier gas to the vaporization tank; a material gas outlet path through which the material gas that is vaporized and outlet from the vaporization tank flows; a dilution gas supply path that merges with the material gas outlet path and supplies dilution gas to the material gas outlet path; a flow control device arranged in at least one of the carrier gas supply path and the dilution gas supply path; and a concentration monitor arranged in the material gas outlet path at a position closer to the downstream side than the confluence point with the dilution gas supply path, the vaporization device repeatedly supplies and stops the material gas, The concentration control device comprises: a concentration calculation section that calculates the concentration of the material gas based on an output signal from the concentration monitor; and a flow rate calculation unit for setting a flow rate calculation unit, which calculates an initial set flow rate of the flow rate control device in an initial interval of a second supply period that is a period until a second scheduled moment during a first supply period for supplying the material gas, based on an actual concentration calculated by the concentration calculation unit at a first scheduled moment during the first supply period, an actual flow rate output from the flow rate control device at a first scheduled moment during the first supply period, or a set flow rate of the flow rate control device at a first scheduled moment during the first supply period, and a preset target concentration, The first predetermined time is the time from the start of the first supply period to the time when the actual concentration in the first supply period has completely decreased from the initial peak. The second predetermined time is the time from the start of the second supply period to the time when the actual concentration in the second supply period has completely decreased from the initial peak. In an initial section of the second supply period, the concentration control device controls the flow rate flowing through the flow control device to become the initial set flow rate.

2. The concentration control device according to claim 1, characterized in that: After the initial section of the second supply period has elapsed, feedback control is performed by controlling the set flow rate of the flow control device so that the actual concentration calculated by the concentration calculation unit approaches the target concentration.

3. The concentration control device according to claim 1, characterized in that: The set flow calculation unit calculates the initial set flow in the initial interval of the second supply period by multiplying the ratio of the target concentration to the actual concentration calculated by the concentration calculation unit at the first predetermined time in the initial interval of the first supply period by the actual flow output from the flow control device at the first predetermined time in the initial interval of the first supply period.

4. The concentration control device according to claim 1, characterized in that: The concentration control device further comprises a flow rate-concentration relationship data storage unit for storing flow rate-concentration relationship data, wherein the flow rate-concentration relationship data represents a relationship between the flow rate of the carrier gas or the flow rate of the dilution gas and the concentration of the material gas flowing in a position closer to the downstream side of the confluence point of the material gas outlet path and the dilution gas supply path, The set flow rate calculation unit calculates the initial set flow rate in an initial section of the second supply period using the flow rate-concentration relationship data.

5. The concentration control device according to claim 1, characterized in that: The set flow rate calculation unit calculates an average initial set flow rate obtained by averaging initial set flow rates calculated for each of a plurality of supply periods during which the material gas is supplied.

6. The concentration control device according to claim 5, characterized in that: The average initial set flow rate is obtained by averaging the initial set flow rate calculated by the set flow rate calculation unit for each supply period in consecutive even-numbered supply periods.

7. A gas control system, characterized in that: have: A vaporization device, comprising: a vaporization tank storing liquid or solid material; a carrier gas supply path for supplying a carrier gas to the vaporization tank; a material gas outlet path through which the material gas that is vaporized and outlet from the vaporization tank flows; a dilution gas supply path that merges with the material gas outlet path and supplies a dilution gas to the material gas outlet path; a flow control device provided in at least one of the carrier gas supply path and the dilution gas supply path; and a concentration monitor provided in the material gas outlet path at a position closer to the downstream side than the confluence point with the dilution gas supply path, wherein the vaporization device repeatedly supplies and stops the material gas; a concentration calculation section that calculates the concentration of the material gas based on an output signal from the concentration monitor; as well as a flow rate calculation unit for setting a flow rate calculation unit, which calculates an initial set flow rate of the flow rate control device in an initial interval from the beginning to the second scheduled time in a second supply period after the first supply period based on an actual concentration calculated by the concentration calculation unit at a first scheduled time in a first supply period for supplying the material gas, an actual flow rate output from the flow rate control device at a first scheduled time in the first supply period or a set flow rate of the flow rate control device at the first scheduled time in the first supply period, and a preset target concentration, The first predetermined time is the time from the start of the first supply period to the time when the actual concentration in the first supply period has completely decreased from the initial peak. The second predetermined time is the time from the start of the second supply period to the time when the actual concentration in the second supply period has completely decreased from the initial peak. In an initial section of the second supply period, the flow rate flowing through the flow control device is controlled to become the initial set flow rate.

8. A film forming device, characterized in that: A gas control system according to claim 7 and a chamber to which the material gas is supplied.

9. A concentration control method, characterized in that: Used in a vaporization device, the vaporization device comprises: a vaporization tank storing liquid or solid materials; a carrier gas supply path for supplying carrier gas to the vaporization tank; a material gas outlet path through which the material gas that is vaporized and outlet from the vaporization tank flows; a dilution gas supply path that merges with the material gas outlet path and supplies dilution gas to the material gas outlet path; a flow control device provided in at least one of the carrier gas supply path and the dilution gas supply path; and a concentration monitor provided in the material gas outlet path at a position closer to the downstream side than the confluence point with the dilution gas supply path, the vaporization device repeatedly supplies and stops the material gas, and the concentration control method comprises: a step of calculating the concentration of the material gas based on an output signal from the concentration monitor; and A step of calculating an initial set flow rate of the flow control device in an initial interval from the beginning to the second scheduled moment in a second supply period after the first supply period based on an actual concentration calculated at a first scheduled moment in a first supply period for supplying the material gas, an actual flow rate output from the flow control device at a first scheduled moment in the first supply period or a set flow rate of the flow control device at a first scheduled moment in the first supply period, and a pre-set target concentration, The first predetermined time is the time from the start of the first supply period to the time when the actual concentration in the first supply period has completely decreased from the initial peak. The second predetermined time is the time from the start of the second supply period to the time when the actual concentration in the second supply period has completely decreased from the initial peak. In an initial section of the second supply period, the flow rate flowing through the flow control device is controlled to become the initial set flow rate.

10. A program recording medium for a concentration control device, characterized in that: A program for a concentration control device for a vaporizer is recorded, the vaporizer comprising: a vaporizer for storing liquid or solid material; a carrier gas supply path for supplying a carrier gas to the vaporizer; a material gas outlet path through which the material gas that is vaporized and outlet from the vaporizer flows; a dilution gas supply path that merges with the material gas outlet path and supplies a dilution gas to the material gas outlet path; a flow control device provided in at least one of the carrier gas supply path and the dilution gas supply path; and a concentration monitor provided in the material gas outlet path at a position closer to the downstream side than the confluence point with the dilution gas supply path, the vaporizer repeatedly supplies and stops the material gas. The concentration control device program recording medium enables the computer to perform the following functions: as a function of a concentration calculation unit, calculating the concentration of the material gas based on an output signal from the concentration monitor; as a function of a set flow rate calculation unit, calculating an initial set flow rate of the flow rate control device in an initial interval from the start to a second scheduled time in a second supply period after the first supply period, based on an actual concentration calculated by the concentration calculation unit at a first scheduled time in a first supply period for supplying the material gas, an actual flow rate output from the flow rate control device at a first scheduled time in the first supply period or a set flow rate of the flow rate control device at a first scheduled time in the first supply period, and a preset target concentration; as well as The concentration control device has a function of controlling the flow rate flowing through the flow control device to become the initial set flow rate in an initial section of the second supply period. The first scheduled time is the time from the start of the first supply period to the time when the actual concentration in the first supply period decreases from the initial peak, and the second scheduled time is the time from the start of the second supply period to the time when the actual concentration in the second supply period decreases from the initial peak.

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