Vaporization device, material state determination device, material state determination method for vaporization device, and material state determination program for vaporization device

Abstract

To accurately determine the liquefaction of the material gas.SOLUTION: A vaporizer that vaporizes a material, a flow rate control device including a flow rate sensor that measures a flow rate of a material gas generated by the vaporizer, and a determination unit that determines that the material gas has returned to a state before the vaporization on the basis of a transient response of the flow rate measured by the flow rate sensor are included.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a vaporizer, a material state determination device, a method for determining the material state of a vaporizer, and a program for determining the material state of a vaporizer.

Background Art

[0002] As this type of vaporizer, for example, there is one that heats and vaporizes a liquid material or a solid material used in semiconductor manufacturing to generate a material gas and supplies this material gas to a semiconductor manufacturing chamber or the like. As shown in Patent Document 1, for example, this vaporizer includes a vaporizer that heats and vaporizes a liquid material or a solid material, and a flow rate control device (so-called mass flow controller) that controls the flow rate of the material gas generated by the vaporizer.

[0003] In this vaporizer, if vaporization failure occurs, such as the generated material gas returning to the state before vaporization, it may cause product failure in semiconductor manufacturing. Therefore, the piping from the flow rate control device and the vaporizer to the flow rate control device is heated by a heater or the like.

[0004] However, in this vaporizer, although the flow rate control device and the piping up to it are heated, the material gas may return to the state before vaporization. Therefore, conventionally, when the deviation between the set flow rate of the flow rate control device and the measured flow rate measured by the flow rate control device continues for a predetermined time, it is determined that there may be a vaporization failure such as the material gas returning to the state before vaporization.

[0005] However, in the above-described detection method, since other factors such as control failure of the flow rate control device are also considered, it is not possible to determine only the possibility of vaporization failure. Furthermore, it is necessary for the deviation to continue for a predetermined time, and the detection of the return to the state before vaporization is delayed. Also, in a thin film formation technique such as atomic layer deposition (ALD), for example, a purge process is inserted during the film formation process, so fluctuations occur in the measured flow rate, making it difficult to detect the return to the state before vaporization.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Therefore, the present invention has been made to solve the above-described problems, and an object thereof is to accurately determine that the material gas has returned to the state before vaporization.

Means for Solving the Problems

[0008] That is, the vaporizer according to the present invention includes a vaporizer that vaporizes a material, a flow control device having a flow sensor that measures the flow rate of the material gas generated by the vaporizer, and a determination unit that determines that the material gas has returned to the state before vaporization based on transient response data that is flow rate data at the time of transient response measured by the flow sensor.

[0009] With such a vaporizer, based on the transient response data measured by the flow sensor, it is determined that the material gas has returned to the state before vaporization, so that it is possible to accurately determine that the material gas has returned to the state before vaporization. Specifically, the transient response data is likely to show the behavior (for example, waveform change) due to the return of the material gas to the state before vaporization, and by using this behavior, it is possible to accurately determine that the material gas has returned to the state before vaporization. Further, in the present invention, an additional sensor for detecting the return to the state before vaporization is not essential, and the device can be miniaturized.

[0010] It is desirable that the determination unit determines that the material gas has returned to the state before vaporization based on differential data obtained by differentiating the transient response data. With this configuration, by differentiating the transient response data, it is possible to easily capture the behavior (e.g., waveform change) due to returning to the state before vaporization included in the transient response data, and it is possible to accurately determine that the material gas has returned to the state before vaporization.

[0011] The behavior (e.g., waveform change) due to returning to the state before vaporization included in the transient response data is considered to appear as an inflection point in the transient response data. Therefore, it is desirable that the determination unit determines that the material gas has returned to the state before vaporization based on the presence or absence of an inflection point in the transient response data.

[0012] Since one inflection point appears due to the change at the rise or the change at the fall during the transient response, in order to capture an inflection point indicating the behavior due to liquefaction other than the change at the rise or the change at the fall, it is desirable that the determination unit determines that the material gas has returned to the state before vaporization when there are two or more inflection points.

[0013] As a specific embodiment for determining that the material gas has returned to the state before vaporization, it is desirable that the determination unit determines that the material gas has returned to the state before vaporization based on the transient response data at the fall.

[0014] In order to more accurately determine that the material gas has returned to the state before vaporization, it is desirable that the determination unit removes noise from the transient response data and determines that the material gas has returned to the state before vaporization based on the transient response data from which the noise has been removed.

[0015] As a specific embodiment when it is determined that the material gas has returned to the state before vaporization, it is desirable that the vaporizer changes the heating temperature of the vaporizer or stops the vaporization operation when the determination unit determines that the material gas has returned to the state before vaporization. Further, by checking whether there is a cold spot portion or the like, the heating temperature of the piping in the vaporizer may be changed or the temperature control area in the vaporizer may be changed.

[0016] If the flow rate sensor is of the thermal type, the behavior due to the return of the material gas to the state before vaporization is likely to appear, and it is possible to more accurately determine that the material gas has returned to the state before vaporization.

[0017] Further, the material state determination device according to the present invention is a material state determination device used in a vaporizer having a vaporizer for vaporizing a material and a flow control device having a flow rate sensor for measuring the flow rate of the material gas generated by the vaporizer, and is based on transient response data which is the flow rate data at the time of transient response measured by the flow rate sensor, and includes a determination unit that determines that the material gas has returned to the state before vaporization.

[0018] Further, the material state determination method of the vaporizer according to the present invention is a material state determination method of a vaporizer having a vaporizer for vaporizing a material and a flow control device having a flow rate sensor for measuring the flow rate of the material gas generated by the vaporizer, and is characterized by determining that the material gas has returned to the state before vaporization based on transient response data which is the flow rate data at the time of transient response measured by the flow rate sensor.

[0019] Furthermore, the material state determination program of the vaporizer according to the present invention is a material state determination program of a vaporizer having a vaporizer for vaporizing a material and a flow control device having a flow rate sensor for measuring the flow rate of the material gas generated by the vaporizer, and is characterized by causing a computer to have a function as a determination unit that determines that the material gas has returned to the state before vaporization based on transient response data which is the flow rate data at the time of transient response measured by the flow rate sensor.

Advantages of the Invention

[0020] As described above, according to the present invention, based on the transient response data of the flow rate sensor, it is determined that the material gas has returned to the state before vaporization, so that it is possible to accurately determine that the material gas has returned to the state before vaporization.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0022] Hereinafter, an embodiment of a vaporizer according to the present invention will be described with reference to the drawings. In addition, for all the figures shown below, for the sake of clarity, they are schematically drawn with appropriate omissions or exaggerations. For the same components, the same reference numerals are given and the description is omitted as appropriate.

[0023] <Configuration of the Vaporizer> The vaporizer 100 of the present embodiment is for heating and vaporizing a liquid material used in semiconductor manufacturing, for example, to generate a material gas and supply this material gas to a semiconductor manufacturing chamber or the like. Note that the vaporizer 100 of the present embodiment vaporizes a liquid material, but it may also vaporize a solid material.

[0024] Specifically, as shown in FIG. 1, the vaporizer 100 includes a vaporizer 2 that vaporizes a liquid material, and a flow rate control device 3 that controls the flow rate of the material gas generated by the vaporizer 2.

[0025] The vaporizer 2 is of the baking type (heating type), and includes a tank 2a for containing a liquid material, a heater 2b for heating the tank 2a, an introduction pipe 2c for supplying the liquid material to the tank 2a, and a lead-out pipe 2d for leading out the material gas generated from the tank 2a.

[0026] The tank 2a contains a predetermined amount of liquid material and is formed of a metal having corrosion resistance such as stainless steel, for example. A liquid level sensor 2e such as a liquid amount sensor is provided in the tank 2a to maintain the liquid material at a predetermined amount. In addition, a pressure sensor 2f for measuring the pressure inside the tank 2a may be provided in the tank 2a.

[0027] The heater 2b is, for example, a heater or the like, and is arranged so as to surround the inside of the tank 2a, or the outer peripheral side surface and / or the bottom surface. Inside the tank 2a heated by this heater 2b, the liquid material reaches the saturated vapor pressure and vaporizes to generate a material gas. The heating temperature by the heater 2b is appropriately set according to the liquid material.

[0028] The introduction pipe 2c is provided so as to penetrate, for example, the upper wall of the tank 2a, and its lower end extends to the vicinity of the bottom surface of the tank 2a. An introduction port P1 for introducing the liquid material is provided at the upstream end of the introduction pipe 2c. In addition, a flow rate adjustment valve 2g for adjusting the flow rate of the liquid material supplied to the tank 2a is provided outside the tank 2a in the introduction pipe 2c. The valve opening degree of this flow rate adjustment valve 2g is controlled based on the detection signal of the liquid amount sensor 2e.

[0029] The discharge pipe 2d opens, for example, on the upper wall of the tank 2a and communicates with the internal space of the tank 2a. The discharge pipe 2d is configured such that the material gas generated inside the tank 2a flows in and is discharged from the tank 2a. A supply port P2 for supplying to a semiconductor manufacturing chamber or the like is provided at the downstream end of the discharge pipe 2d. An on-off valve 2h is provided in the discharge pipe 2d, and the on-off valve 2h is closed when the material gas is not discharged from the tank 2a. The discharge pipe 2d is heated to a predetermined temperature by a heater 2i so that the material gas does not liquefy from the connection part of the tank 2a to the supply port P2.

[0030] Furthermore, in the discharge pipe 2d, a purge gas supply pipe 2j for supplying a purge gas is connected between the on-off valve 2h and a flow rate control device 3 described later. A supply port P3 for supplying the purge gas is provided at the upstream end of the purge gas supply pipe 2j. An on-off valve 2k is provided in the purge gas supply pipe 2j, and the on-off valve 2k is closed when the purge gas is not supplied.

[0031] The flow rate control device 3 is provided in the discharge pipe 2d and controls the flow rate of the material gas flowing through the discharge pipe 2d. Specifically, the flow rate control device 3 includes a flow rate sensor 31 that measures the flow rate of the material gas, a fluid control valve 32 provided on the upstream side or the downstream side (here, the downstream side) of the flow rate sensor 31, and a valve control unit 33 that controls the fluid control valve 32 based on the measured flow rate of the flow rate sensor 31.

[0032] The flow rate sensor 31 is a thermal flow rate sensor and includes a sensor pipe 31a through which the material gas flows, a sensing unit 31b that detects a physical quantity (for example, current, voltage, resistance, etc.) related to the temperatures on the upstream side and the downstream side of the sensor pipe 31a, and a flow rate calculation unit 31c that calculates the flow rate of the material gas based on the detection signal obtained by the sensing unit 31b.

[0033] The sensor pipe 31a has its upstream end and downstream end connected to the discharge pipe 2d and bypasses a part of the material gas.

[0034] The sensing unit 31b uses a thermistor whose electrical resistance value increases or decreases with temperature change, and includes an upstream sensor 31b1 wound around the upstream side of the sensor pipe 31a in a coil shape and a downstream sensor 31b2 wound around the downstream side of the sensor pipe 31a in a coil shape.

[0035] The flow rate calculation unit 31c is composed of an electric circuit, and includes a control circuit that controls the temperatures of the upstream sensor 31b1 and the downstream sensor 31b2 to be always equal and constant, an amplifier circuit that amplifies the electrical signal output by the control circuit, and a conversion circuit that converts the electrical signal amplified by this amplifier circuit into a flow rate. Note that the flow rate calculation unit 31c may also flow a constant current through the upstream sensor 31b1 and the downstream sensor 31b2 by a constant current circuit and convert the temperature difference between the upstream sensor 31b1 and the downstream sensor 31b2 at that time into a flow rate.

[0036] The valve control unit 33 controls the fluid control valve 32 based on the measured flow rate of the material gas calculated by the flow rate calculation unit 31c. Note that the valve control unit 33 is a so-called computer equipped with, for example, a CPU, a memory, an A / D·D / A converter, and input / output means, and controls the fluid control valve 32 by executing a program stored in the memory and having various devices cooperate with each other.

[0037] Specifically, the valve control unit 33 performs flow rate feedback control on the opening degree of the fluid control valve 32 so that the deviation between the set flow rate set by the user and the measured flow rate calculated by the flow rate calculation unit 31c becomes small. This valve control unit 33 is a PID controller that receives the deviation between the set flow rate and the measured flow rate and outputs a voltage command applied to the fluid control valve 32 by PID calculation.

[0038] <Liquefaction judgment function> Furthermore, the vaporizer 100 of the present embodiment has a function of determining that the material gas has returned to the state before vaporization, that is, a function of determining that the material gas has liquefied. Here, "determining that the material gas has returned to the state before vaporization" means, in the case of a solid material, determining that the material gas has returned to a solid state, and in the case of a liquid material, determining that the material gas has returned to a liquid state.

[0039] Specifically, the vaporizer 100 includes a liquefaction determination unit 4 that determines that the material gas has liquefied based on transient response data, which is the flow rate data during transient response measured by the flow rate sensor 31. Note that the transient response data may be analog data or digital data.

[0040] Here, the transient response is at the falling edge, and the liquefaction determination unit 4 determines that the material gas has liquefied based on the transient response data at the falling edge. Note that the falling edge (transient response) of the measured flow rate occurs, for example, when the set flow rate (set value) of the flow rate control device 3 is changed from a predetermined flow rate (for example, a flow rate greater than zero such as 500 [sccm]) to zero and the flow control valve 32 is fully closed.

[0041] The liquefaction determination unit 4 may be configured such that its function is exerted by storing a liquefaction determination program in the memory of the same computer as the valve control unit 33 described above, or its function may be exerted by storing a liquefaction determination program in the memory of a computer different from the valve control unit 33. Note that the liquefaction determination unit 4 may be provided with its function in the flow rate control device 3 or in the semiconductor manufacturing apparatus.

[0042] Specifically, as shown in FIG. 2, the liquefaction determination unit 4 determines that the material gas has liquefied based on differential data obtained by differentiating the transient response data with respect to time. Specifically, the liquefaction determination unit 4 detects the presence or absence of an inflection point in the transient response data from the differential data, and determines that the material gas has liquefied based on the presence or absence of the inflection point.

[0043] Here, as shown in FIG. 2(a), the liquefaction determination unit 4 determines that the material gas has liquefied when there are two or more inflection points. This is because when there is no liquefaction, as shown in FIG. 2(b), one inflection point appears due to the change during the fall in the transient response, so as to capture the inflection point indicating the behavior due to liquefaction in addition to the change due to the fall.

[0044] Further, the liquefaction determination unit 4 may remove noise such as flow rate noise and disturbance influence from the transient response data, and determine that the material gas has liquefied based on the transient response data from which the noise has been removed. Here, as a method for removing noise, for example, moving averaging the transient response data can be considered.

[0045] Furthermore, when it is determined by the liquefaction determination unit 4 that the material gas has liquefied, it is conceivable to configure to notify the user of the liquefaction of the material gas. Specifically, it is conceivable to perform liquefaction determination display on the display 5 of the computer, or to notify by sound or light by a notification device provided on the line (site) incorporating the vaporizer 100.

[0046] Moreover, when it is determined by the liquefaction determination unit 4 that the material gas has liquefied, the vaporizer 100 may also perform control to change (specifically, increase) the heating temperature of the vaporizer 2 or stop the vaporization operation. In addition, it is also possible to check whether there is no cold spot portion and change the heating temperature of the piping of the vaporizer 100 or change the temperature control area.

[0047] <Effects of this Embodiment> As described above, according to the vaporizer 100 in this embodiment, based on the transient response data measured by the flow rate sensor 31, it is determined that the material gas has liquefied, so it is possible to accurately determine that the material gas has liquefied. Specifically, the behavior due to the liquefaction of the material gas (for example, waveform change) is likely to appear in the transient response data, and by using the behavior due to the liquefaction, it is possible to accurately determine the liquefaction of the material gas.

[0048] In addition, since the liquefaction determination unit 4 determines that the material gas has liquefied based on the differential data obtained by differentiating the transient response data, it is possible to easily capture the behavior due to liquefaction (e.g., waveform change) included in the transient response data, and accurately determine the liquefaction of the material gas.

[0049] Furthermore, in this embodiment, since the thermal flow sensor 31 is used, the behavior due to the liquefaction of the material gas is likely to appear, and the liquefaction of the material gas can be determined even more accurately.

[0050] <Other Embodiments> For example, the method for determining liquefaction by the liquefaction determination unit 4 is not limited to being based on the inflection point, and liquefaction may be determined based on the change amount of the differential data. For example, when the change amount of the differential data is equal to or greater than a predetermined value, or when the change amount of the differential data is less than the predetermined value and does not become zero within a predetermined time, etc.

[0051] Specifically, in order not to make an incorrect determination due to the operation of the shut-off valve on the vaporizer side during the falling response, a threshold value is set for the differential value of the transient response data at the time of falling, and a configuration is adopted in which liquefaction is not determined for a sharp response associated with the operation of the shut-off valve or the like. For example, when a falling signal is detected, an inflection point is confirmed in the differential data within a predetermined time after the detection, and the differential data is within a predetermined range, it is conceivable to determine that the material gas has liquefied. Here, an appropriate value is set for the predetermined range according to the film formation conditions of the semiconductor manufacturing process.

[0052] Also, it is conceivable that the liquefaction determination unit 4 is configured to determine liquefaction without differentiating the transient response data. In this case, for example, the transient response data obtained by the flow sensor 31 is compared with the transient response data (standard data) in a state where liquefaction has not occurred, for example, by fitting, and liquefaction is determined based on the comparison result.

[0053] Furthermore, although the flow sensor in the above embodiment is of the thermal type, it may be of the pressure type or of other measurement principles.

[0054] In the above embodiment, the vaporizer 100 is provided with a function of determining that the material gas has liquefied, but it may be configured by a device different from the vaporizer 100 (liquefaction determination device). That is, the liquefaction determination unit 4 may be provided in a device different from the vaporizer 100.

[0055] The vaporizer of the above embodiment is of the baking type, but it may be of the bubbling type in which a carrier gas is introduced into the liquid material and vaporized by bubbling, or of the bubbling type in which a carrier gas is sprayed onto the solid material to sublime it.

[0056] In addition, various modifications and combinations of embodiments may be made as long as they do not depart from the spirit of the present invention.

Explanation of Reference Numerals

[0057] 100 ··· Vaporizer 2 ··· Vaporizer 3 ··· Flow control device 31 ··· Flow sensor 4 ··· Liquefaction determination unit (determination unit)

Claims

1. A vaporizer for vaporizing a material, A flow control device having a flow sensor for measuring the flow rate of the material gas generated by the vaporizer, A vaporization device comprising: a determination unit that determines that the material gas has returned to a state before being vaporized based on transient response data that is flow rate data during a transient response measured by the flow sensor.

2. The vaporization device according to claim 1, wherein the determination unit determines that the material gas has returned to a state before being vaporized based on differential data obtained by differentiating the transient response data.

3. The vaporization device according to claim 2, wherein the determination unit determines that the material gas has returned to a state before being vaporized based on the presence or absence of an inflection point in the transient response data.

4. The vaporization device according to claim 1, wherein the determination unit determines that the material gas has returned to a state before being vaporized when there are two or more inflection points in the transient response data.

5. The vaporization device according to any one of claims 1 to 4, wherein the determination unit determines that the material gas has returned to a state before being vaporized based on the transient response data at the time of fall.

6. The vaporization device according to any one of claims 1 to 5, wherein the determination unit removes noise from the transient response data and determines that the material gas has returned to a state before being vaporized based on the transient response data from which the noise has been removed.

7. When the determination unit determines that the material gas has returned to a state before being vaporized, changing the heating temperature of the vaporizer or the pipe, changing the temperature control area, or stopping the vaporization operation. The vaporization device according to any one of claims 1 to 6.

8. The vaporization device according to any one of claims 1 to 7, wherein the flow sensor is a thermal flow sensor.

9. A liquefaction determination device used in a vaporization device having a vaporizer that vaporizes a material and a flow control device having a flow sensor that measures the flow rate of the material gas generated by the vaporizer, comprising a determination unit that determines that the material gas has returned to the state before vaporization based on transient response data, which is the flow rate data at the time of transient response measured by the flow sensor. A material state determination device.

10. A method for determining the material state of a vaporization device having a vaporizer that vaporizes a material and a flow control device having a flow sensor that measures the flow rate of the material gas generated by the vaporizer, The method for determining the material state of a vaporization device, which determines that the material gas has returned to the state before vaporization based on transient response data, which is the flow rate data at the time of transient response measured by the flow sensor.

11. A program for determining the material state of a vaporization device having a vaporizer that vaporizes a material and a flow control device having a flow sensor that measures the flow rate of the material gas generated by the vaporizer, causing a computer to be provided with a function as a determination unit that determines that the material gas has returned to the state before vaporization based on transient response data, which is the flow rate data at the time of transient response measured by the flow sensor. A program for determining the material state of a vaporization device.

Images