Vaporizer and vaporization system

Abstract

To provide a vaporizer and vaporization system which can suppress pressure fluctuations within a tank due to bubble generation.SOLUTION: A vaporizer for vaporizing a liquid material includes a tank for containing the liquid material, a heater for heating the tank to heat the liquid material, and a porous structure which is provided within the tank, divides bubbles generated due to the heating of the liquid material by the heater, and makes them pass through itself.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to vaporizers and vaporization systems. [Background technology]

[0002] In a conventional baking type vaporizer, a tank containing a liquid material is heated by a heater to vaporize the liquid material and generate gas. Such a baking type vaporizer is disclosed in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 195349 Summary of the Invention [Problem to be solved by the invention]

[0004] In a baking type vaporizer, when the tank is heated, the liquid material in the tank boils and generates bubbles. When bubbles are generated, the pressure in the tank fluctuates. This pressure fluctuation can affect the output flow rate of a flow control device (also called a mass flow controller) arranged on the secondary side of the tank. For example, fluctuations in the pressure in the tank can cause the stability of the above flow rate to be lost. In particular, in a small and compact vaporizer, since the tank is also small, the generation of bubbles can easily cause the pressure in the tank to fluctuate, and the stability of the above flow rate can be easily lost.

[0005] The present invention has been made to solve the above problems, and its object is to provide a vaporizer and vaporization system that can suppress pressure fluctuations in a tank caused by the generation of bubbles. [Means for solving the problem]

[0006] An vaporizer according to one aspect of the present invention is a vaporizer that vaporizes a liquid material, and includes a tank that stores the liquid material, a heater that heats the tank and thereby the liquid material, and a porous structure that is disposed within the tank and divides and allows air bubbles generated by heating the liquid material by the heater to pass through.

[0007] A vaporization system according to another aspect of the present invention includes the vaporizer described above, and a flow rate control device that controls a flow rate of the gas of the liquid material vaporized by the vaporizer. Effect of the Invention

[0008] According to the present invention, pressure fluctuations in the tank caused by the generation of air bubbles can be suppressed. [Brief description of the drawings]

[0009] [Figure 1] 1 is a perspective view showing a schematic configuration of an evaporation system according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a perspective view showing a schematic configuration of a vaporizer of the vaporization system. [Diagram 3] FIG. 2 is a cross-sectional view illustrating a schematic configuration of the vaporizer. [Figure 4] 3A and 3B are plan views showing a porous structure provided in the vaporizer before and after being placed in a tank. [Diagram 5] 13A-13C are plan views of another porous structure, before and after placement in a tank. [Figure 6] FIG. 4 is a cross-sectional view illustrating a schematic configuration of the vaporizer. [Figure 7] FIG. 11 is a perspective view showing a modified example of the bottom plate portion of the tank. [Figure 8] FIG. 11 is a cross-sectional view showing a schematic configuration of the vaporizer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. In each drawing, for convenience of explanation, the vertical direction of the vaporization system is defined as the Z direction, and two directions perpendicular to the Z direction and perpendicular to each other are defined as the X direction and the Y direction, respectively.

[0011] [1. Configuration of the vaporization system] 1 is a perspective view showing a schematic configuration of a vaporization system 100 according to the present embodiment. The vaporization system 100 includes a first valve 2, a vaporizer 3, a pressure sensor 4, a second valve 5, a third valve 6, and a flow control device 7 in a substantially rectangular parallelepiped housing 1. Note that in FIG. 1, the front side wall of the housing 1 is omitted in order to clarify the internal configuration of the housing 1.

[0012] The first valve 2, the vaporizer 3, the pressure sensor 4, the second valve 5, the third valve 6, and the flow control device 7 are fixed to a side surface 1s of a main body block 1a provided in the housing 1. The main body block 1a is provided extending in the vertical direction within the housing 1. Inside the main body block 1a, a flow path for a liquid material (hereinafter also referred to as a liquid flow path) and a flow path for a gas (hereinafter also referred to as a gas flow path) are formed. In FIG. 1, the direction in which the liquid material flows within the main body block 1a is indicated by a solid arrow, and the direction in which the gas flows is indicated by a dashed arrow. The liquid material is appropriately selected from various materials used, for example, in semiconductor manufacturing processes.

[0013] The first valve 2 is a control valve (liquid material supply valve) that controls the supply flow rate of the liquid material to the vaporizer 3, and is composed of, for example, an electromagnetic on-off valve. When the first valve 2 is opened, the liquid material is introduced into the main body block 1a from the liquid material supply port 1b located at the bottom of the main body block 1a. The introduced liquid material is supplied into the tank 31 of the vaporizer 3 via the first valve 2 and a liquid flow path in the main body block 1a. On the other hand, when the first valve 2 is closed, the supply of the liquid material to the tank 31 is stopped.

[0014] The vaporizer 3 vaporizes the liquid material by a baking method. The detailed configuration of the vaporizer 3 will be described later. The pressure sensor 4 is a sensor that detects the pressure in the tank 31 of the vaporizer 3, and is provided to monitor the pressure.

[0015] The second valve 5 is an on-off valve that opens and closes the flow path of gas (hereinafter also referred to as material gas) generated by vaporizing the liquid material in the vaporizer 3. When the second valve 5 is opened, the material gas generated in the tank 31 of the vaporizer 3 passes through the gas flow path in the main body block 1a and is supplied to the flow control device 7. On the other hand, when the second valve 5 is closed, the supply of the material gas to the flow control device 7 is stopped.

[0016] The third valve 6 is an on-off valve that opens and closes the flow path of the purge gas. For example, when only the flow control device 7 is purged, such as after replacing the flow control device 7, the second valve 5 is kept closed and the third valve 6 is opened. In this case, the purge gas supplied through a purge gas flow path (not shown) passes through the gas flow path in the main body block 1a via the third valve 6 and is introduced into the flow control device 7. When the entire vaporization system 100 is purged, the second valve 5 and the third valve 6 are both opened to perform the purge.

[0017] The flow rate control device 7 controls the flow rate of the gas of the liquid material vaporized by the vaporizer 3. Such a flow rate control device 7 is composed of, for example, a mass flow controller. The material gas outputted with the flow rate controlled by the flow rate control device 7 is introduced into an external device (for example, a semiconductor manufacturing device) via a gas outlet 1c provided on the upper part of the main body block 1a.

[0018] [2. Detailed configuration of the vaporizer] Fig. 2 is a perspective view that typically shows the configuration of vaporizer 3. Fig. 3 is a cross-sectional view that typically shows the configuration of vaporizer 3. Vaporizer 3 includes tank 31, heater 32, porous structure 33, liquid level detection sensor 34, and temperature sensor 35.

[0019] The tank 31 is a metal container that contains the liquid material LQ supplied from the liquid material supply port 1b (see FIG. 1). The heater 32 is disposed in the tank 31. In the example of FIG. 2 and FIG. 3, the heater 32 is configured as a cartridge heater 32a and is embedded in the bottom plate portion 31A that constitutes the bottom of the tank 31. That is, the tank 31 has the bottom plate portion 31A on which the heater 32 is disposed. The cartridge heater 32a has a structure in which a nichrome wire, which is a heating element, is covered with a metal pipe. When the heater 32 is energized to generate heat, the bottom plate portion 31A is heated and the heat of the bottom plate portion 31A is transferred to the liquid material LQ. As a result, the liquid material LQ boils and vaporizes, and bubbles BU, which are material gas, are generated. In this way, the vaporizer 3 includes the heater 32 that heats the tank 31 (bottom plate portion 31A) to heat the liquid material LQ (inside).

[0020] The porous structure 33 is disposed in the tank 31. In the example of Fig. 2 and Fig. 3, the porous structure 33 is disposed in the tank 31 at a position above the bottom plate portion 31A and spaced a predetermined distance from the bottom plate portion 31A. Therefore, the porous structure 33 is located above the heater 32 embedded in the bottom plate portion 31A and spaced apart from the heater 32. The porous structure 33 is also located in contact with the side wall 31W of the tank 31 and spaced a predetermined distance from the heating surface (bottom plate portion 31A). The porous structure 33 divides and passes through the above-mentioned air bubbles BU generated by heating the liquid material LQ by the heater 32.

[0021] The porous structure 33 is disposed at a position where bubbles BU due to boiling will not be generated even if heat is transmitted from the heater 32. That is, in this embodiment, even if heat is transmitted from the heater 32 to the porous structure 33, bubbles BU themselves due to boiling of the liquid material LQ will not be generated at the position of the porous structure 33.

[0022] FIG. 4 is a plan view showing the porous structure 33 before and after it is placed in the tank 31. The porous structure 33 is composed of, for example, a porous plate. The porous plate has a structure in which a metallic flat plate 33a having a rectangular shape in a plan view is provided with a plurality of holes P that penetrate in the vertical direction. The size (inner diameter) of the holes P is smaller than the size (outer diameter) of the bubbles BU to be generated. If the holes P are too small, stable vaporization of the liquid material LQ may be hindered. For this reason, it is desirable to set the size of the holes P (particularly the lower limit of the inner diameter) to a size that can realize stable vaporization of the liquid material LQ. The density of the holes P (the number of holes P per unit area) may be set appropriately.

[0023] The size of the bubbles BU that are generated by heating the liquid material LQ differs depending on the type of liquid material LQ used, but no matter which liquid material is used, the outer diameter is, for example, about 10 mm. Therefore, if the holes P are formed with an inner diameter of, for example, 1 to 2 mm, a common (one type of) porous structure 33 can be used no matter what liquid material LQ is used.

[0024] Such a porous structure 33 is joined to the inner surface (side wall 31W) of the tank 31 by, for example, welding. In the example of Fig. 4, the entire outer edge portion 33R constituting the outer shape of the porous structure 33 in a plan view is in contact with and welded to the inner surface of the tank 31. As a result, as shown in Figs. 2 and 3, the porous structure 33 is disposed so as to cover the bottom plate portion 31A of the tank 31 from above.

[0025] The liquid level detection sensor 34 is a sensor that detects the liquid level S (see FIG. 3) of the liquid material LQ in the tank 31, and is also called a float sensor. As shown in FIG. 2, the liquid level detection sensor 34 includes a low-level detection sensor 34L and a high-level detection sensor 34H. The low-level detection sensor 34L has a low-level float part 34L1 that moves up and down within a predetermined operating range according to the height of the liquid level S. The high-level detection sensor 34H has a high-level float part 34H1 that moves up and down within a predetermined operating range according to the height of the liquid level S. The vertical operating range of the low-level float part 34L1 is lower than the vertical operating range of the high-level float part 34H1. The low-level detection sensor 34L and the high-level detection sensor 34H are fixed to the upper wall of the tank 31 by welding and are provided so as to penetrate the upper wall.

[0026] In this embodiment, a controller (not shown) controls the first valve 2 (see FIG. 1) to open and close intermittently so that the liquid level S of the liquid material LQ in the tank 31 is located between the low-level side float part 34L1 and the high-level side float part 34H1. This intermittently controls the supply of the liquid material LQ into the tank 31.

[0027] The temperature sensor 35 is disposed between the heater 32 and the liquid level detection sensor 34 (particularly the low-level detection sensor 34L), and detects the temperature of the liquid material LQ. The temperature sensor 35 is configured with, for example, a thermocouple. Based on the temperature detected by the temperature sensor 35, the controller controls the supply of electricity to the heater 32 so that the temperature becomes a temperature at which the liquid material LQ in the tank 31 vaporizes.

[0028] In this manner, in a configuration in which the evaporator 3 is equipped with a liquid level detection sensor 34 and a temperature sensor 35, the above-mentioned porous structure 33 is positioned between the liquid level detection sensor 34 and the temperature sensor 35, as shown in FIG. 3.

[0029] In the above configuration, in the tank 31, the liquid material LQ is heated by the heater 32, whereby the liquid material LQ boils and generates bubbles BU. The generated bubbles BU are finely divided by the multiple pores P when passing through the porous structure 33. As a result, the bubbles BU after passing through the porous structure 33 are smaller than the bubbles BU before passing through the porous structure 33, that is, the bubbles BU generated by heating (see Figs. 2 and 3). Therefore, it is possible to suppress pressure fluctuations in the tank 31 caused by the generation of bubbles BU. As a result, even when the flow rate control device 7 is disposed on the secondary side of the tank 31 to control the flow rate of the gas of the liquid material LQ, it is possible to output the gas at a stable flow rate. In particular, the structure of this embodiment is very effective in a vaporizer 3 that employs a heating vaporization method that is prone to sudden pressure fluctuations such as bumping, rather than a bubbling vaporization method in which small bubbles are continuously generated.

[0030] In a configuration in which the porous structure 33 is positioned above and away from the heater 32 as in this embodiment, bubbles BU are once generated between the porous structure 33 and the heater 32 by the heating of the liquid material LQ by the heater 32. The bubbles BU once generated then enter the porous structure 33 and are divided into small bubbles as they pass through the porous structure 33. This ensures that the function of the porous structure 33 to finely divide the bubbles BU generated by the heating of the heater 32 and allow them to pass through can be achieved.

[0031] In addition, the porous structure 33 is disposed so as to cover the bottom plate portion 31A of the tank 31. Therefore, by heating with the heater 32, air bubbles BU generated between the bottom plate portion 31A and the porous structure 33 in the tank 31 can be guided to the porous structure 33 without leakage and passed through the porous structure 33. In other words, all air bubbles BU generated by heating with the heater 32 can be guided to the porous structure 33 and passed therethrough. This ensures that the size of the generated air bubbles BU can be reduced by the porous structure 33.

[0032] In addition, the porous structure 33 is disposed between the liquid level detection sensor 34 and the temperature sensor 35. Therefore, the generated air bubbles BU can be made smaller by the porous structure 33 without impeding the liquid level detection by the liquid level detection sensor 34 and the temperature detection by the temperature sensor 35. In addition, the limited space between the liquid level detection sensor 34 and the temperature sensor 35 can be effectively used as the arrangement space for the porous structure 33.

[0033] The porous structure 33 is a porous plate having a flat plate 33a with a plurality of holes P. Such a porous plate has a simple structure and is easy to manufacture. Therefore, the porous structure 33 can be easily realized by using the porous plate.

[0034] 3. Other configurations of the carburetor 5 is a plan view showing another porous structure 33 before and after being placed in a tank 31. As shown in the figure, the porous structure 33 may be configured such that an opening (notch) P1 corresponding to a part of the hole P is provided in an outer peripheral portion 33R. In this case, a part of the outer peripheral portion 33R of the porous structure 33, i.e., a part of the outer peripheral portion 33R other than the opening P1, contacts the inner surface of the tank 31 and is joined by welding. Even in this case, the porous structure 33 can be considered to be configured to be placed so as to cover the bottom plate portion 31A of the tank 31.

[0035] 6 is a cross-sectional view showing a schematic diagram of another configuration of the vaporizer 3. As shown in the figure, the porous structure 33 may be arranged so that a part of the porous structure 33 is in contact with the bottom plate portion 31A. Specifically, the porous structure 33 may have a configuration having a first region F1 and a second region F2. Here, the first region F1 is an area of ​​the porous structure 33 that is arranged so as to cover the heater 32 and is located above and away from the bottom plate portion 31A. The second region F2 is an area of ​​the porous structure 33 other than the first region F1, and is an area that is connected to the first region F1 and in contact with the bottom plate portion 31A.

[0036] Even with this configuration, the liquid material LQ located between the first region F1 of the porous structure 33 and the bottom plate portion 31A can be boiled and vaporized by heating with the heater 32 to generate bubbles BU, and the generated bubbles BU can be finely divided when passing through the porous structure 33 (for example, the first region F1). Therefore, it can be said that the vaporizer 3 of this embodiment is not limited to a configuration in which the entire porous structure 33 is located away from the bottom plate portion 31A (heater 32).

[0037] 7 is a perspective view showing a schematic modification of the bottom plate portion 31A of the tank 31. The bottom plate portion 31A has a heating surface 31S. The heating surface 31S is a surface that comes into contact with the liquid material LQ (see FIG. 3, etc.) in the tank 31. The heating surface 31S is heated by a heater 32 embedded in the bottom plate portion 31A. The heating surface 31S has a groove G above the heater 32. In the heating surface 31S, the groove G is formed, for example, in a lattice shape, but may be a groove formed along only one direction (for example, the Y direction in FIG. 7) or may have a curved shape.

[0038] When the liquid material LQ is heated by the heater 32, the liquid material LQ evaporates from the vicinity of the heating surface 31S of the bottom plate portion 31A, generating bubbles BU. At this time, because grooves G are present above the heater 32 on the heating surface 31S, small bubbles BU can be generated from the gaps in the grooves G. In other words, the bubbles BU themselves generated by the heating of the heater 32 can be made small. As a result, due to the synergistic effect with the division of the bubbles BU by the porous structure 33, the size of the bubbles BU can be reliably reduced, and pressure fluctuations within the tank 31 can be reliably suppressed.

[0039] In the above, an example has been described in which an embedded cartridge heater 32a (see FIG. 3, etc.) is used as the heater 32, but the heater 32 used is not limited to the cartridge heater 32a. FIG. 8 is a cross-sectional view that shows a schematic diagram of still another configuration of the vaporizer 3. As shown in the figure, a rubber heater 32b may be used as the heater 32. In this case, the heater 32 (rubber heater 32b) is provided on the outside (outer surface) of the bottom plate portion 31A, and heats the tank 31 from the bottom. As a result, the liquid material LQ in the tank 31 is heated, and bubbles BU are generated.

[0040] Even when the rubber heater 32b is used, by disposing the porous structure 33 inside the tank 31, the size of the bubbles BU generated by the heating of the liquid material LQ by the rubber heater 32b can be reduced by dividing the bubbles BU when passing through the porous structure 33. This makes it possible to suppress pressure fluctuations inside the tank 31 caused by the generation of the bubbles BU.

[0041] [4. Supplementary Information] The porous structure 33 is not limited to the porous plate used in this embodiment, and may be, for example, a structure having a metallic mesh structure.

[0042] Although the embodiment of the present invention has been described above, the scope of the present invention is not limited to this, and the invention can be expanded or modified without departing from the spirit of the invention. [Industrial Applicability]

[0043] The present invention can be used, for example, in a vaporizer provided at the upstream stage of a semiconductor manufacturing device. [Explanation of symbols]

[0044] 3. Carburetor 7 Flow Control Device 31 Tank 31A Bottom plate part 31S heating surface 32 Heater 33 Porous structure 33a flat plate 34 Liquid level detection sensor 35 Temperature Sensor 100 Vaporization System BU bubbles G groove LQ Liquid Material P hole S liquid level

Claims

1. 1. A vaporizer for vaporizing a liquid material, comprising: A tank for containing the liquid material; a heater for heating the tank to heat the liquid material; a porous structure disposed within the tank, the porous structure dividing and allowing air bubbles generated by heating the liquid material by the heater to pass therethrough.

2. The vaporizer of claim 1 , wherein the porous structure is located remote from the heater.

3. the tank has a bottom plate portion on which the heater is disposed, The vaporizer according to claim 1 or 2, wherein the porous structure is disposed so as to cover the bottom plate portion.

4. 4. The vaporizer according to claim 1, wherein the porous structure is a porous plate having a plurality of holes formed in a flat plate.

5. The heater is embedded in the bottom plate portion, the bottom plate portion has a heating surface that is in contact with the liquid material in the tank and is heated by the heater, the heating surface has a groove above the heater; 4. The carburetor of claim 3.

6. a liquid level detection sensor that detects the liquid level of the liquid material in the tank; a temperature sensor disposed between the heater and the liquid level sensor for detecting a temperature of the liquid material; The vaporizer according to claim 1 , wherein the porous structure is disposed between the liquid level detection sensor and the temperature sensor.

7. A vaporizer according to any one of claims 1 to 6; a flow rate control device that controls the flow rate of the gas of the liquid material vaporized by the vaporizer.

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