Gas Supply Equipment

Abstract

To efficiently supply mixed gas of component gas and carrier gas by a compact device configuration.SOLUTION: A mixed gas supply device 1 comprises: an evaporator 10 for heating a liquid component and carrier gas, and producing mixed gas of component gas formed by evaporating the liquid component and the carrier gas; and a cooler 30 for cooling the mixed gas produced by the evaporator 10, and supplying the mixed gas of the component gas formed by condensing and separating a supersaturated content and the carrier gas. The evaporator 10 comprises a shell-and-tube type heating mechanism, and tubes 16, 17 for carrier gas with holes 16H, 17H for bubbling the carrier gas opened at plural portions extend in a shell 11 of the evaporator 10 in a horizontal direction. A liquid component supply port 20 is provided at a lower part of the shell 11 of the evaporator 10, and a feeding port 23 for feeding the mixed gas of the component gas formed by evaporating the liquid component and the carrier gas is provided at an upper part of the shell 11 of the evaporator 10. A lower part of the cooler 30 is continued to the feeding port 23 of the evaporator 10 by a pipeline 31.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a gas supply device, and more particularly to a gas supply device useful for supplying a mixed gas of trichlorosilane and hydrogen used in the semiconductor industry and the like. [Background technology]

[0002] Mixed gases of carrier gases and component gases have been used in the semiconductor industry, etc. For example, in the manufacturing process of semiconductor epitaxial silicon wafers, a mixed gas containing trichlorosilane gas as the component gas and hydrogen gas as the carrier gas is used.

[0003] A known supply device for a mixed gas of trichlorosilane gas and hydrogen gas is one that introduces a mixed gas of supersaturated trichlorosilane gas and hydrogen gas into a cooler, condenses and separates the supersaturated trichlorosilane, and delivers a mixed gas of saturated trichlorosilane gas and hydrogen gas from the cooler (Patent Document 1). It is also known that in such a gas supply device, liquid trichlorosilane and hydrogen gas are introduced into an evaporator to obtain a mixed gas of supersaturated trichlorosilane gas and hydrogen gas (Patent Documents 2 and 3). In the evaporator, the liquid trichlorosilane is vaporized while bubbling with hydrogen gas, producing a mixed gas of trichlorosilane gas and hydrogen gas. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4542643 [Patent Document 2] Patent No. 4505077 [Patent Document 3] Patent No. 6503293 Summary of the Invention [Problem to be solved by the invention]

[0005] In the gas supply device described above, a heater or a jacket-type heat medium heating method is used as the heating method for the evaporator. However, there has been a demand for a more compact device configuration and for efficiently producing a mixed gas of supersaturated trichlorosilane gas and hydrogen. [Means for solving the problem]

[0006] The inventors of the present invention conceived that if liquid trichlorosilane is supplied from the lower part of the body of a shell-and-tube heater used as an evaporator and a tube with multiple bubbling holes is extended into the body to bubble hydrogen gas through the liquid chlorosilane, a mixed gas of supersaturated trichlorosilane gas and hydrogen gas can be efficiently produced and the evaporator can be made compact, thereby completing the present invention.

[0007] That is, the present invention provides an evaporator that heats a liquid component and a carrier gas to generate a mixed gas of the component gas vaporized from the liquid component and the carrier gas; A cooler that cools the mixed gas produced in the evaporator and supplies a mixed gas of the component gases and carrier gas that have been condensed and separated to remove the supersaturated gas. A mixed gas supply device comprising: The evaporator has a cylindrical shell with its axis oriented horizontally, and is equipped with a shell-and-tube type heating mechanism having heat medium tubes extending in the axial direction within the shell, Inside the evaporator body, a carrier gas tube with multiple holes for bubbling the carrier gas extends horizontally. A liquid component supply port is provided at the bottom of the evaporator body, An outlet is provided at the top of the evaporator body for delivering a mixed gas of a component gas obtained by vaporizing a liquid component and a carrier gas, The mixed gas supply device has a lower part of a cooler connected to the outlet of an evaporator through piping and also connected to a liquid component supply port through piping, and condensed liquid formed in the cooler returns from the liquid component supply port to the inside of the body of the evaporator. [Effects of the Invention]

[0008] The mixed gas supply device of the present invention uses an evaporator equipped with a shell-and-tube heating mechanism, which allows for efficient heating and vaporization of liquid components. Furthermore, the evaporator body equipped with the shell-and-tube heating mechanism includes a carrier gas tube with multiple holes for bubbling the carrier gas. This allows the vaporized liquid component to be captured in the bubbles of the carrier gas generated by bubbling, allowing for efficient generation of a supersaturated mixed gas of the component gas and the carrier gas. Therefore, the evaporator can be made smaller, and the entire mixed gas supply device can be made compact. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the configuration of a mixed gas supply device according to an embodiment. [Figure 2] FIG. 2 is an exploded view of the evaporator of the mixed gas supply device of the embodiment. [Figure 3] FIG. 3 is a perspective view of the hydrogen inlet tube plate of the mixed gas supply device of the embodiment, as viewed from the inside of the evaporator. [Figure 4] FIG. 4 is a diagram showing the arrangement of the heat transfer medium tubes in the tube sheet grooves. [Figure 5] FIG. 5 is a cutaway cross-sectional view of the observation window. [Figure 6] FIG. 6 is a plan view of the carrier gas tube as seen from the bottom side of the evaporator. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below with reference to the drawings, in which the same reference numerals denote the same or equivalent components.

[0011] 1 is a configuration diagram of a mixed gas supply apparatus 1 according to one embodiment of the present invention. This mixed gas supply apparatus 1 is preferably used to supply a mixed gas of trichlorosilane gas and hydrogen gas adjusted to a saturated concentration (hereinafter also referred to as a concentration-adjusted gas). The mixed gas supply apparatus 1 includes an evaporator 10 and a cooler 30.

[0012] Liquid trichlorosilane is supplied as a liquid component and hydrogen gas is supplied as a carrier gas to the evaporator 10. The evaporator 10 heats these components to vaporize the liquid trichlorosilane into trichlorosilane gas, and generates a mixed gas of trichlorosilane gas and hydrogen gas as component gases. The mixed gas is supersaturated with trichlorosilane.

[0013] The evaporator 10 has a shell-and-tube heating mechanism as its heating mechanism. That is, the evaporator 10 has a cylindrical shell 11 with an axis A oriented horizontally, and a plurality of heat transfer medium tubes 12 extending in the A-axis direction within the shell 11. In the present invention, to increase the heating efficiency of the evaporator 10, it is preferable to make the heat transfer medium travel back and forth a plurality of times between tube sheets 13, 14 on both sides of the shell 11 through a flow path formed by a plurality of heat transfer medium tubes 12. In this case, the large number of heat transfer medium tubes can be divided into a plurality of groups, each formed by a plurality of heat transfer medium tubes, so that the outward or return path of each of the multiple round trips is formed by a plurality of heat transfer medium tubes, and each group can be used as the outward or return path. For example, as shown by the flow directions of arrows (1) to (10) in Figure 2, the heat medium flowing in from the tube sheet 13 at one end of the shell 11 is directed toward the other tube sheet 14 via a plurality of heat medium tubes 12 in group 1 (arrow 1), then directed from the other tube sheet 14 toward one tube sheet 13 via a plurality of heat medium tubes 12 in group 2 (arrow 2), and then directed again from this tube sheet 13 toward the other tube sheet 14 via a plurality of heat medium tubes 12 in group 3. This process is repeated, and the heat medium makes five round trips between one tube sheet 13 and the other tube sheet 14 using the heat medium tubes 12 in groups 1 to 10. In this case, six tube sheet grooves 13A are provided on the inner surface of one tube sheet 13, and five tube sheet grooves 14A are provided on the inner surface of the other tube sheet 14, and the tube sheet grooves connect the flow paths of the outbound group and the return group. 4 is a diagram showing the arrangement of groups 1 (G1) to 10 (G10) of the heat transfer medium tubes in the tube sheet grooves 14 of the tube sheet 14. Each of the groups G1 to G10 is surrounded by a dashed line.

[0014] As the heat transfer medium, a known inert substance can be used, for example, Fluorinert (registered trademark), Galden (registered trademark), etc.

[0015] By using the above-mentioned multiple heat transfer medium tubes 12 and providing a flow path for the heat transfer medium to travel back and forth between the opposing tube sheets 13 and 14 multiple times, the thermal efficiency of heating the liquid component in the evaporator 10 is improved, allowing the evaporator 10 to be made more compact in the present invention. Therefore, for example, when 18 to 32% trichlorosilane gas is supplied from the cooler 30 to three channels at a flow rate of 16 g / min, the evaporator 10 shell 11 can be made compact, with an outer diameter of 130 to 220 mm and a length in the axial direction A of 350 to 500 mm. For example, stainless steel pipes with an inner diameter of approximately 20 mm can be used as the individual heat transfer medium tubes. In this case, the temperature inside the shell 11 is maintained at a predetermined temperature, for example, 25 to 40°C, by the heat transfer medium.

[0016] In the mixed gas supply device 1 of this embodiment, the tube plates 13 and 14 of the shell-and-tube type heating mechanism of the evaporator 10 are fixed tube plates, but in the present invention, the tube plates of the shell-and-tube type heating mechanism may be U-shaped, floating head type, etc.

[0017] Carrier gas tubes 16 and 17 extend horizontally within the body 11 of the evaporator 10. More specifically, a supply pipe 15 for hydrogen gas used as a carrier gas is connected to a tube sheet 14, and two straight carrier gas tubes 16 and 17 are connected to the pipe 15. A thermometer T1 for measuring the temperature within the body 11 is provided on this tube sheet 14 (FIG. 1).

[0018] The carrier gas tubes 16, 17 are parallel to the lower ones of the heat transfer medium tubes 12 and extend in the axial direction A from one tube sheet 14 toward the opposing tube sheet 13 near the bottom of the shell 11, reaching the vicinity of the tube sheet 13. In this embodiment, the carrier gas tubes 16, 17 extend linearly from one tube sheet 14 toward the opposing tube sheet 13, but the present invention is not limited to this. For example, the number of carrier gas tubes may be three or more, or they may be bent. Furthermore, while the heat transfer medium flow path described above travels back and forth between the opposing tube sheets 13, 14 via the heat transfer medium tubes 12 and the tube sheet grooves 13A, 14A, the carrier gas tubes 16, 17 extend from one tube sheet 14 but do not reach the other tube sheet 13, and the ends of each carrier gas tube 16, 17 are closed. By forming the carrier gas tubes 16, 17 as straight tubes with closed ends, the configuration of the evaporator 10 can be simplified.

[0019] As shown in Figure 6, the carrier gas tubes 16, 17 have downward holes 16H, 17H as carrier gas bubbling holes. In the present invention, when multiple carrier gas tubes are arranged in parallel at the bottom of the evaporator body 11, it is preferable that adjacent carrier gas bubbling holes are formed alternately in the axial A direction of the evaporator body 11. Furthermore, by making the holes 16H, 17H downward holes, the carrier gas bubbles released from the holes 16H, 17H are in contact with the liquid components accumulated in the body 11 for a longer period of time, and the component gases vaporized from the liquid components are more likely to be captured in the bubbles.

[0020] Meanwhile, a liquid component supply port 20 is formed in the lower part of the body 11 of the evaporator 10, in the center in the axial A direction, and liquid trichlorosilane is supplied as a liquid component from the liquid component supply port 20 into the body 11 through an evaporator lower-end valve 21. That is, liquid trichlorosilane supplied under pressure from a liquid component supply valve 22 is supplied to the liquid component supply port 20 through the evaporator lower-end valve 21. Liquid trichlorosilane condensed in the cooler 30 is also supplied from piping 37 into the body 11 through the evaporator lower-end valve 21 and the liquid component supply port 20.

[0021] It is preferable to provide a liquid level gauge between the liquid component supply port 20 and the lower end of the cooler 30 to detect the liquid level in the body 11 and to appropriately manage the liquid level in the body 11.

[0022] An outlet 23 is formed in the upper part of the body 11 of the evaporator 10, in the center in the axial A direction, for delivering a mixed gas of component gases produced by vaporization of liquid components in the body 11 and carrier gas bubbled through holes 16H and 17H of the carrier gas tube. The opening diameter L1 of the mixed gas outlet 23 is preferably 50% to 100%, more preferably 60 to 80%, of the inner diameter L2 of the body, in order to accommodate the pressure gauge P, safety valve, piping 31, and observation window 33 within the area of ​​this opening diameter and to configure the evaporator 10 compactly.

[0023] The mixed gas outlet 23 has a flange 24 at the connection portion with the pipe 31 connected to the bottom of the cooler 30. The pipe 31 connected to the bottom of the cooler 30 also has a flange 32, which is joined to the flange 24. An observation window 33 for observing the inside of the body 11 of the evaporator 10 is provided in the area surrounded by the flange 32. The observation window 33 is formed by sandwiching optically polished transparent tempered glass 33G between a flange 33F1 and a holding flange 33F2 (FIG. 5). To isolate the inside of the body 11 from the outside air, it is preferable to sandwich an appropriate seal member between the two flanges 33F1 and 33F2. The observation window 33 preferably has a diameter of 20 to 40 mm. This allows for easy visual observation of the bubbling state of the carrier gas inside the body 11.

[0024] A pressure gauge P for measuring the pressure inside the shell 11 of the evaporator 10, a pressure regulator, and a control valve are provided in the area surrounded by the flange 32, and the pressure inside the shell 11 is controlled to, for example, 0.09 to 0.17 MPa (G). Also, a pressure release valve 25 is provided to release gas inside the shell 11 in case of a pressure increase due to some cause. Furthermore, the above-mentioned piping 31 is provided with a gate valve 34. By virtue of the gate valve 34, the mixed gas supply device 1 does not fall under the category of a "pressure vessel" as defined by regulations, making it easier to handle.

[0025] The mixed gas delivered from the delivery port 23 of the evaporator 10 is supplied to the lower part of the cooler 30 through a pipe 31 .

[0026] In the present invention, the cooler 30 can be similar to the coolers described in Patent Documents 2 and 3, and a multi-tube heat exchanger can be used, for example. Specifically, the cooler 30 has a plurality of tubes 35 through which the mixed gas from the evaporator 10 passes, and a refrigerant flow path 36 that flows around the plurality of tubes 35. Thermometers T2 are provided at multiple locations on the tubes 35 through which the mixed gas passes, and the temperature is monitored. The refrigerant flows from the upper to lower sections of the cooler 30, and the temperature inside the cooler 30 is controlled to, for example, 10 to 20°C. In particular, since the concentration of the component gas at the concentration adjustment gas supply port 38 is determined by the system pressure and condensation temperature, it is preferable to control the temperature of the refrigerant supplied to the upper section of the cooler 30 within a predetermined range (preferably ±0.1°C) using a chiller.

[0027] The mixed gas delivered from the evaporator 10 is cooled by the refrigerant flowing through the flow path 36 while passing through the tube 35, causing the supersaturated trichlorosilane to condense and separate, and the condensed and separated liquid trichlorosilane is sent from the lower end of the cooler 30 through the pipe 37 to the liquid component supply port 20 of the evaporator 10. Meanwhile, a mixed gas of saturated concentration trichlorosilane gas and hydrogen gas is supplied as a concentration adjustment gas from the concentration adjustment gas supply port 38 at the upper end of the cooler 30. A flow meter F and a concentration meter are provided at the concentration adjustment gas supply port 38, and the amount of the mixed gas delivered from the evaporator 10 to the cooler 30 is controlled according to the amount of concentration adjustment gas supplied.

[0028] Thus, according to the mixed gas supply device 1 of this embodiment, a mixed gas of trichlorosilane gas and hydrogen gas adjusted to a predetermined saturated concentration can be supplied with high concentration stability, and furthermore, the device configuration can be made compact.

[0029] The mixed gas supply device of the present invention is not limited to supplying a mixed gas of trichlorosilane gas and hydrogen gas, but can also be suitably used to supply, for example, a mixed gas of tetrachlorosilane gas and hydrogen gas, a mixed gas of trichlorosilane and argon, a mixed gas of methyltrichlorosilane gas and hydrogen gas, etc. [Explanation of symbols]

[0030] 1. Mixed gas supply device 10 Evaporator 11 Torso 12 Heat transfer tube 13 Tube plate 13A Tube plate groove 14 Tube plate 14A Tube plate groove 15 Piping 16 Carrier gas tube 16H Carrier gas bubbling hole 17 Carrier gas tube 17H Carrier gas bubbling hole 20 Liquid component supply port 21 Evaporator bottom valve 22 Liquid component refill valve 23 Outlet 24 flange 25 Pressure release valve 30 Cooler 31 Piping 32 flange 33 Observation window inside the evaporator body 34 Gate valve 35 tubes 36 Refrigerant flow path 37 Piping 38 Concentration adjustment gas supply port A-axis F Flowmeter P pressure gauge T1, T2 thermometer

Claims

1. an evaporator that heats the liquid component and the carrier gas to generate a mixed gas of the component gas vaporized from the liquid component and the carrier gas; A cooler that cools the mixed gas produced in the evaporator and supplies a mixed gas of the component gases and carrier gas that have been condensed and separated to remove the supersaturated gas. A mixed gas supply device comprising: The evaporator has a cylindrical shell with its axis oriented horizontally, and is equipped with a shell-and-tube type heating mechanism having heat medium tubes extending in the axial direction within the shell, Within the evaporator body, a carrier gas tube having a plurality of holes for bubbling the carrier gas extends from one end of the cylindrical body to the other end, A liquid component supply port is provided at the bottom of the evaporator body, An outlet is provided at the top of the evaporator body for delivering a mixed gas of a component gas obtained by vaporizing a liquid component and a carrier gas, A mixed gas supply device in which the lower part of the cooler is connected to the outlet of the evaporator by piping and also to the liquid component supply port by piping, and the condensed liquid formed in the cooler returns to the body of the evaporator from the liquid component supply port.

2. 2. A mixed gas supply device according to claim 1, wherein the carrier gas tubes extend from one tube plate to the opposite tube plate in the axial direction of the evaporator body.

3. 2. The mixed gas supply device according to claim 1, wherein the carrier gas tube has a hole that opens downward as a hole for bubbling the carrier gas.

4. 4. A mixed gas supply device according to claim 3, wherein a plurality of carrier gas tubes are arranged in parallel at the bottom of the body, and the bubbling holes of adjacent carrier gas tubes are formed alternately in the axial direction of the evaporator body.

5. 5. The mixed gas supply device according to claim 1, wherein the opening diameter of the delivery port of the evaporator is 50% or more of the inner diameter of the body.

6. 5. The mixed gas supply device according to claim 1, wherein the heat transfer medium flowing through the heat transfer medium tubes travels back and forth between the tube plates at both ends of the shell a plurality of times from when it is introduced into the shell until it is discharged.

7. 5. The mixed gas supply device according to claim 1, wherein a window for observing the inside of the body of the evaporator is provided at a connection between the outlet of the evaporator and the piping extending from the lower part of the cooler.

8. 5. The mixed gas supply device according to claim 1, wherein the liquid component is liquid trichlorosilane and the carrier gas is hydrogen gas.

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