Semiconductor process gas purification apparatus and semiconductor process gas purification method

Abstract

The present invention provides a semiconductor process gas purification system that can repeatedly purify and regenerate semiconductor process gases and purification equipment without cooling them to extremely low temperatures or reducing purification efficiency. [Solution] A process gas purification apparatus comprising a cylindrical container, a heater positioned to cover the outer surface of the container, and a cooling gas pipe passing through the inside of the container, wherein the container is filled with a purifying agent for adsorbing impurity gases contained in the semiconductor process gas to be purified, and a semiconductor process gas inlet and outlet are provided for passing the semiconductor process gas to be purified through and bringing it into contact with the purifying agent, and the cooling gas pipe is covered with the purifying agent inside the container.

Description

Technical Field

[0004] , , , , , , , , , , ,

[0005] , , , , , ,

[0001] The present invention relates to a semiconductor process gas purification apparatus for removing impurity gases contained in a semiconductor process gas to an extremely low concentration to obtain a high-purity semiconductor process gas. [[ID=​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​The present invention has been made in view of the above circumstances, and aims to provide a semiconductor process gas purification apparatus that can repeatedly purify and regenerate semiconductor process gases and purification apparatus without cooling them to extremely low temperatures and without reducing the purification efficiency. [Means for solving the problem]

[0006] To achieve the above objectives, the present invention employs the following configuration. [1] A cylindrical container, a heater positioned to cover the outer surface of the container, and a cooling gas pipe passing through the inside of the container, The container is filled with a purifying agent for adsorbing impurity gases contained in the semiconductor process gas to be purified, and is provided with a pre-purification gas inlet and a post-purification gas outlet for passing the semiconductor process gas to be purified through and bringing it into contact with the purifying agent. A semiconductor process gas purification apparatus characterized in that the cooling gas piping is covered with the purifying agent inside the container. [2] The semiconductor process gas purification apparatus according to [1], wherein the cooling gas piping inside the container is spiral-shaped. [3] A semiconductor process gas purification apparatus according to [1] or [2], further comprising a cooling device that supplies cooling gas to the cooling gas piping. [4] A semiconductor process gas purification apparatus according to any one of [1] to [3], wherein the purifying agent is an adsorbent having pores capable of adsorbing the impurity gas. [5] A semiconductor process gas purification method comprising the steps of purifying a semiconductor process gas to be purified by bringing it into contact with a cooled purifying agent to adsorb impurity gases, and regenerating the purifying agent by heating it to remove the desorbed impurity gases and then pushing them out with an inert gas. [6] The semiconductor process gas purification method according to [5], wherein the purifying agent is an adsorbent having pores capable of adsorbing the impurity gas. [7] The semiconductor process gas purification method according to [5] or [6], wherein the semiconductor process gas to be purified is a gas selected from halogen gases, halides, and hydrides. [8] The semiconductor process gas purification method according to [5] to [7], wherein the semiconductor process gas to be purified is selected from the group consisting of boron trifluoride, phosphorus trifluoride, chlorine trifluoride, fluorine, hydrogen fluoride, chlorine, hydrogen chloride, carbonyl sulfide, and hydrazine. [Effects of the Invention]

[0007] According to the semiconductor process gas purification apparatus of the present invention, semiconductor process gases can be purified without cooling the purification apparatus to an extremely low temperature. The semiconductor process gas purification apparatus of the present invention can repeatedly perform purification and regeneration without reducing purification efficiency. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of a semiconductor process gas purification apparatus according to the first embodiment of the present invention. [Figure 2] This is one embodiment of a semiconductor process gas purification system incorporating two semiconductor process gas purification devices shown in Figure 1. [Figure 3] This is the evaluation system used in the example. [Figure 4] This is the evaluation result of the purification apparatus in Example 1. [Figure 5] This is the evaluation result of the purification apparatus in Example 2. [Figure 6] This is the evaluation result of the purification apparatus in Example 3. [Figure 7] This is the evaluation result of the purification apparatus for Comparative Example 1. [Modes for carrying out the invention]

[0009] <Semiconductor process gas purification equipment> [First Embodiment] FIG. 1 is a configuration diagram schematically showing a semiconductor process gas purification apparatus 1 according to the first embodiment of the present invention. The semiconductor process gas purification apparatus 1 of the present embodiment includes a cylindrical container 10, a heater 20 disposed so as to cover the outer peripheral surface of the container 10, and a cooling gas pipe 30 passing through the inside of the container 10.

[0010] The container 10 in the present embodiment includes a cylindrical container body 11, and container end portions 12a and 12b that close both ends thereof, and is filled with a purification agent 50 inside. In addition, a pre-purification gas inlet 42 is provided at the container end portion 12a, and a post-purification gas outlet 43 is provided at the container end portion 12b. The semiconductor process gas to be purified (hereinafter sometimes referred to as "target gas") can be passed through the inside of the container body 11 from the pre-purification gas inlet 42 and to the post-purification gas outlet 43 while being brought into contact with the purification agent 50.

[0011] A pre-purification gas introduction connection portion 40 for connecting an introduction pipe of the semiconductor process gas before purification (hereinafter sometimes referred to as "pre-purification gas") is attached to the pre-purification gas inlet 42. A post-purification gas导出 connection portion 41 for connecting a导出 pipe of the semiconductor process gas after purification (hereinafter sometimes referred to as "post-purification gas") is attached to the post-purification gas outlet 43.

[0012] The purification agent 50 in the present embodiment uses an adsorbent capable of adsorbing impurity gases. As the type of the purification agent 50, an adsorbent having pores capable of adsorbing impurity gases, an adsorbent utilizing a chemical reaction with impurity gases, etc. are applicable, and among them, an adsorbent having pores capable of adsorbing impurity gases is preferable. Examples of the adsorbent having pores capable of adsorbing impurity gases include molecular sieves, activated carbon, activated alumina, and the like.

[0013] Molecular sieves are crystalline zeolites and porous materials with pores. Molecules that enter the pores stay by adsorption, so molecules can be adsorbed thereby. There are multiple types of molecular sieves with different pore diameters. For example, if the pore diameter is 0.3 nm, molecules with a diameter less than 0.3 nm can be adsorbed. Therefore, by selecting the pore diameter according to the molecules to be adsorbed, molecules can be selectively adsorbed. Taking the case where it is desired to adsorb carbon dioxide contained in the target gas as an example, since the diameter of carbon dioxide is 0.33 nm, a molecular sieve with a pore diameter of 1.0 nm or the like can be applied.

[0014] The heater 20 is cylindrical and coaxial with the container body 11, and is arranged to cover the container body 11.

[0015] The cooling gas pipe 30 is arranged to pass through the inside of the container 10, and both ends thereof are outside the container 10. In this embodiment, both ends of the cooling gas pipe 30 pass through the container end 12b in an airtight manner and reach the outside of the container 10. At both ends of the cooling gas pipe 30, a cooling gas introduction connection part 31 for connecting an introduction pipe of the cooling gas and a cooling gas discharge connection part 32 for connecting a discharge pipe of the cooling gas are respectively connected. Note that the introduction pipe and the discharge pipe of the cooling gas are connected to a cooling device (not shown). The cooling device is configured to cool the cooling gas from the discharge pipe of the cooling gas again and supply it to the introduction pipe of the cooling gas.

[0016] The cooling gas pipe 30 passes through the container end 12b from the side where the cooling gas introduction connection part 31 is attached and reaches the inside of the container 10, and its tip reaches near the container end 12a while being spirally wound. Then, the tip turns back, passes outside the wound part, passes through the container end 12b again, and reaches the side where the cooling gas discharge connection part 32 is attached.

[0017] [Other Embodiments] There are no particular limitations on the specific shape of the container in the semiconductor process gas purification apparatus of the present invention. The container may have a cross-sectional shape that is not a straight line, for example, a bent container or a curved U-shaped tube.

[0018] There are no particular limitations on the positional relationship between the pre-purification gas inlet 42 and the post-purification gas outlet 43 in the container; they can be placed at any position on the container. For example, in the container 10 of the first embodiment, they may be provided on the side of the container body 11.

[0019] There are no particular limitations on the shape and positional relationship of the cooling gas piping 30; it is not limited to a spiral shape, but may be straight, for example. However, from the viewpoint of uniformly and rapidly cooling the inside of the container 10, it is preferable that it be spiral, as shown in the first embodiment. Regardless of its shape, it is preferable that the cooling gas piping 30 be widely distributed throughout the inside of the container. Furthermore, there are no particular limitations on the position where both ends of the cooling gas piping 30 exit the container. In the case of the container 10 in the first embodiment, they may exit from the side of the container body 11. Alternatively, one end may exit from the container end 12a.

[0020] <Method for purifying semiconductor process gases> The semiconductor process gas purification method of this embodiment includes a purification step of purifying the semiconductor process gas to be purified (target gas) by bringing it into contact with a cooled purifying agent to adsorb impurity gases, and a step of regenerating the purifying agent by passing an inert gas through the heated purifying agent to remove the impurity gases. Prior to the purification process, it is preferable to perform a cooling step to cool the purified agent. In other words, it is preferable to perform a cooling step after the regeneration process. However, if the purified agent can be cooled in a very short time, the cooling step may be omitted, and cooling may be started simultaneously with the start of the purification process.

[0021] In the purification process, the pre-purification gas is brought into contact with the purifying agent, causing impurities in the pre-purification gas to be adsorbed onto the purifying agent, resulting in a purified gas from which the impurities have been removed. During the purification process, the purifying agent is cooled, which helps to avoid altering the purifying agent by allowing the target gas to adsorb onto it.

[0022] In the regeneration process, the purifying agent that has adsorbed impurity gases is heated to desorb the adsorbed impurity gases, and the desorbed impurity gases can be discharged with an inert gas. The semiconductor process gas purification method of this embodiment can be suitably carried out using the semiconductor process gas purification apparatus of the above embodiment.

[0023] Highly reactive gases are preferred as the target gas. This is because highly reactive gases readily alter the purifying agent at room temperature, making the present invention suitably applicable to them. As specific target gases, semiconductor process gases selected from the group consisting of halogen gases, halides, and hydrides are preferred.

[0024] Halogen gases are halogens in their gaseous state and elemental form. Examples of halogen gases include fluorine gas, chlorine gas, bromine gas, and iodine gas. Halides are compounds of halogens and elements with lower electronegativity. Examples of halides include silicon dioxide, silane trichloride, silicon tetrachloride, silicon tetrafluoride, arsenic fluoride, arsenic trifluoride, arsenic pentafluoride, arsenic trichloride, arsenic pentachloride, phosphorus trifluoride, phosphorus pentafluoride, phosphorus trichloride, phosphorus pentachloride, phosphorus oxychloride, boron trifluoride, boron trichloride, boron tribromide, nitrogen trifluoride, sulfur tetrafluoride, tungsten hexafluoride, molybdenum hexafluoride, germanium tetrachloride, and tin hexachloride. Examples include antimony pentachloride, tungsten hexachloride, molybdenum hexachloride, carbon tetrafluoride, methane trifluoride, methane difluoride, propane hexafluoride, propane octafluoride, promemethane trifluoride, hydrogen fluoride, hydrogen chloride, carbon tetrachloride, hydrogen bromide, sulfur hexafluoride, chlorine trifluoride, fluorine, tetrachlorosilane, trichlorosilane, dichlorosilane, hexachlorodisilane, chlorine, and carbonyl sulfide.

[0025] A hydride is a compound of hydrogen with an element that has a lower electronegativity. Examples of hydrides include monosilane, disilane, arsine, phosphine, diborane, hydrogen selenide, monogermane, hydrogen telluride, stivin, tin hydride, trimethylgallium, triethylgallium, trimethylindium, triethylindium, hydrogen sulfide, ammonia, trimethylamine, ethane, propane, trimethylaluminum, and hydrazine.

[0026] The target gas is particularly preferably one selected from the group consisting of boron trifluoride, phosphorus trifluoride, chlorine trifluoride, fluorine, hydrogen fluoride, chlorine, hydrogen chloride, carbonyl sulfide, and hydrazine. Examples of inert gases used in the regeneration process include nitrogen, helium, neon, argon, krypton, xenon, and radon.

[0027] Each step will be described in detail, using the semiconductor process gas purification apparatus 1 of the first embodiment described above as an example. In the cooling process, the purifying agent 50 inside the container 10, which is at room temperature or heated, is cooled. Specifically, the cooling gas cooled by the cooling device is introduced into the cooling gas piping 30 via the cooling gas introduction connection 31, passes through the inside of the container 10, and thereby cools the purifying agent 50 covering the cooling gas piping 30. The cooling gas that has passed through the inside of the container 10 is returned to the cooling device via the cooling gas outlet connection 32.

[0028] The temperature of the purifying agent 50 at the end of the cooling process and the temperature of the purifying agent 50 during the purification process are preferably 20 to -100°C, and more preferably 0 to -50°C, depending on the type of gas being targeted. If the above temperature is below the preferred upper limit, purification with the purifying agent 50 can be carried out stably. If the above temperature is above the preferred lower limit, excessive cooling equipment and excessive energy consumption can be avoided.

[0029] During the purification process, the cooling gas is continuously supplied to the cooling gas piping 30. In the purification process, the pre-purification gas is introduced to the pre-purification gas inlet 42 via the pre-purification gas introduction connection 40. The pre-purification gas introduced to the pre-purification gas inlet 42 comes into contact with the cooled purifying agent 50 and is discharged as the post-purification gas to the post-purification gas outlet 43. The post-purification gas discharged to the post-purification gas outlet 43 then flows out from the post-purification gas discharge connection 41. The introduction of the pre-purification gas can be continued as long as the purifying agent 50 maintains its purification capacity.

[0030] In the regeneration process, the introduction of cooling gas is stopped, and the purifying agent 50 is heated by the heater 20. In addition, an inert gas is introduced into the pre-purification gas inlet 42 via the pre-purification gas introduction connection 40. By flowing the inert gas, impurity gases that have been released from the purifying agent 50 due to heating can be discharged. After that, heating by the heater 20 is stopped.

[0031] The semiconductor process gas purification method of this embodiment allows for repeated use of the purifying agent by alternating between purification and regeneration steps. If a cooling step is performed prior to each purification step, the purifying agent can be used stably for a longer period of time.

[0032] <Semiconductor process gas purification system> Figure 2 shows one embodiment of a semiconductor process gas purification system incorporating the semiconductor process gas purification apparatus of the present invention. The system of this embodiment consists of a purification apparatus 1A, a purification apparatus 1B and a plurality of pipes connected thereto, and a plurality of on-off valves provided in the pipes. There are no particular limitations on the specific configurations of the purification apparatus 1A and the purification apparatus 1B, but it is preferable that they be the semiconductor process gas purification apparatuses in the above embodiment, and in particular, it is preferable that they be the semiconductor process gas purification apparatus 1 of the first embodiment.

[0033] The piping consists of a pre-purification gas introduction pipe L10 for introducing the pre-purification gas into one of the purification devices, and branch pipes L11 and L12 branching off from the pre-purification gas introduction pipe L10. Branch pipe L11 is connected to purification device 1A, and branch pipe L12 is connected to purification device 1B. When these purification devices are the semiconductor process gas purification device 1 of the first embodiment, the connection point between branch pipe L11 and branch pipe L12 is the pre-purification gas introduction connection section 40 in Figure 1. A normally open valve V1 is provided in branch pipe L11, and a normally closed valve V2 is provided in branch pipe L12. The unpurified gas flowing in from the unpurified gas introduction pipe L10 is guided to one of the purification devices via one of the branch pipes.

[0034] The piping also includes an inert gas introduction pipe L20 for introducing an inert gas into one of the purification devices, and branch pipes L21 and L22 branching off from the inert gas introduction pipe L20. Branch pipe L21 is connected to purification device 1A, and branch pipe L22 is connected to purification device 1B. When these purification devices are the semiconductor process gas purification device 1 of the first embodiment, the connection point between branch pipe L21 and branch pipe L22 is the pre-purification gas introduction connection section 40 in Figure 1. A normally closed valve V3 is provided in branch pipe L21, and a normally open valve V4 is provided in branch pipe L22. The inert gas flowing in from the inert gas introduction pipe L20 is guided to one of the purification devices via one of the branch pipes.

[0035] Furthermore, the downstream ends of branch pipes L11 and L21 merge to form a single pipe connected to purification unit 1A. Similarly, the downstream ends of branch pipes L12 and L22 merge to form a single pipe connected to purification unit 1B.

[0036] The piping also includes a purified gas outlet pipe L30 for discharging purified gas discharged from one of the purification devices, and branch pipes L31 and L32 that merge with the purified gas outlet pipe L30. Branch pipe L31 is connected to purification device 1A, and branch pipe L32 is connected to purification device 1B. When these purification devices are the semiconductor process gas purification device 1 of the first embodiment, the connection point between branch pipes L31 and L32 is the purified gas outlet connection section 41 in Figure 1. A normally open valve V5 is provided in branch pipe L31, and a normally closed valve V6 is provided in branch pipe L32. The purified gas flowing out from either purification device is guided to the purified gas outlet pipe L30 via either branch pipe.

[0037] The piping also includes a discharge pipe L40 for the flow of impurity gases discharged from one of the purification devices, and branch pipes L41 and L42 that merge into the discharge pipe L40. Branch pipe L41 is connected to purification device 1A, and branch pipe L42 is connected to purification device 1B. When these purification devices are the semiconductor process gas purification device 1 of the first embodiment, the connection point between branch pipes L41 and L42 is the purified gas discharge connection section 41 in Figure 1. A normally closed valve V7 is provided in branch pipe L41, and a normally open valve V8 is provided in branch pipe L42, so that impurity gas flowing out from either purification unit is guided to the discharge pipe L40 via either branch pipe.

[0038] Furthermore, the upstream ends of branch pipes L31 and L41 merge into a single pipe and are connected to purification unit 1A. Similarly, the upstream ends of branch pipes L32 and L42 merge into a single pipe and are connected to purification unit 1B.

[0039] The piping also includes cooling gas inlet pipes L50A and L50B for introducing cooling gas to one of the purification devices, and cooling gas outlet pipes L51A and L51B for dischargering cooling gas that has flowed out of one of the purification devices. When these purification devices are the semiconductor process gas purification device 1 of the first embodiment, the connection point between cooling gas inlet pipe L50A and cooling gas inlet pipe L50B is the cooling gas inlet connection part 31 in Figure 1, and the connection point between cooling gas outlet pipe L51A and cooling gas outlet pipe L51B is the cooling gas outlet connection part 32 in Figure 1.

[0040] Furthermore, the cooling gas cooled by the cooling device (not shown in the diagram) is supplied to either the cooling gas inlet pipe L50A or the cooling gas inlet pipe L50B via a switching valve (not shown in the diagram). The cooling gas discharged from cooling gas outlet pipes L51A and L51B is introduced into the cooling device via a switching valve (not shown in the diagram), where it is cooled again and circulated. If it is necessary to supply cooling gas to both cooling gas inlet pipe L50A and cooling gas inlet pipe L50B simultaneously, you can either install two cooling units or connect both cooling gas inlet and outlet pipes to a single cooling unit.

[0041] <Operation Method of Semiconductor Process Gas Purification System> The semiconductor process gas purification system shown in Figure 2 can continuously purify the target gas by switching between purification unit 1A and purification unit 1B. If the process of purifying the target gas using purification device 1A is referred to as the 1A purification process, then during the 1A purification process, purification device 1B is in the regeneration process. Similarly, if the process of purifying the target gas using purification device 1B is referred to as the 1B purification process, then during the 1B purification process, purification device 1A is in the regeneration process. In this embodiment, the purification steps 1A and 1B can be repeated.

[0042] If a cooling process is performed prior to the purification process, the purification apparatus 1B performs a regeneration process and a cooling process following the regeneration process during the purification process 1A. Alternatively, the purification apparatus 1A performs a regeneration process and a cooling process following the regeneration process during the purification process 1B. This allows one purification unit to move from the purification process to the regeneration process while the other purification unit is sufficiently cooled.

[0043] [1A purification process] During the 1A purification process, the heater 20 of the purification unit 1A is stopped, and the cooling gas is introduced into the cooling gas inlet pipe L50A and discharged from the cooling gas outlet pipe L51A, thereby circulating within the cooling gas piping of the purification unit 1A. In the 1A purification process, all normally open valves shown in Figure 2 are opened and all normally closed valves are closed, and purification is performed using the purification apparatus 1A.

[0044] Specifically, the pre-purification gas introduced into the pre-purification gas introduction pipe L10 passes through the normally open valve V1 located in the branch pipe L11 and is introduced into the purification device 1A, where impurity gases are removed by the purifying agent. Since the normally closed valve V2 is closed, the pre-purification gas does not flow into the purification device 1B. Also, since the normally closed valve V3 is closed, the inert gas from the inert gas introduction pipe L20 does not flow into the purification device 1A.

[0045] The unpurified gas introduced into the purification unit 1A is purified and, as purified gas, passes through the normally open valve V5 located in the branch pipe L31 and is discharged to the purified gas outlet pipe L30. Since the normally closed valve V7 is closed, the purified gas does not flow into the discharge pipe L40. Also, since the normally closed valve V6 is closed, the gas that flows out from the purification unit 1B is not discharged to the purified gas outlet pipe L30.

[0046] As described above, the purification apparatus 1B during the 1A purification process is in the regeneration process, or in the regeneration process and the subsequent cooling process. During the regeneration process, the refining agent 50 in the refining unit 1B is heated by the heater 20, and the supply of cooling gas is stopped. In this state, all normally open valves shown in Figure 2 are opened, and all normally closed valves are closed, and the regeneration of the refining unit 1B is performed.

[0047] Specifically, the inert gas introduced into the inert gas introduction pipe L20 passes through the normally open valve V4 located in the branch pipe L22 and is introduced into the purification unit 1B. Since the normally closed valve V3 is closed, the inert gas does not flow into the purification unit 1A. Also, since the normally closed valve V2 is closed, the pre-purification gas from the pre-purification gas introduction pipe L10 does not flow into the purification unit 1B.

[0048] The inert gas introduced into the purification unit 1B pushes out the impurity gases that have been separated from the purifying agent by heating with the heater 20. The pushed-out impurity gases, along with the inert gas, pass through the normally open valve V8 located in the branch pipe L42 and are discharged from the discharge pipe L40. Since the normally closed valve V6 is closed, the impurity gases and inert gas discharged from the purification unit 1B are not discharged into the purified gas outlet pipe L30. Also, since the normally closed valve V7 is closed, the purified gas that has flowed out of the purification unit 1A is not discharged into the discharge pipe L40.

[0049] During the 1A purification process, when the cooling process is performed in the purification apparatus 1B following the regeneration process, the open and closed states of each normally open valve and normally closed valve are maintained as they were in the regeneration process, and the heater 20 of the purification apparatus 1B is stopped. In addition, cooling gas is introduced into the cooling gas inlet pipe L50B, and the cooling gas is discharged from the cooling gas outlet pipe L51B, thereby circulating within the cooling gas piping of the purification apparatus 1B. During the cooling process, the introduction of inert gas into the purification apparatus 1B may be stopped, but it is preferable to continue it in order to remove any trace amounts of adsorbed components remaining in the purification apparatus 1B.

[0050] [1B purification process] When switching from the 1A purification process to the 1B purification process, the normally open valves are closed and the normally closed valves are opened. During the 1B purification process, the heater 20 of the purification unit 1B is stopped, and the cooling gas is introduced into the cooling gas inlet pipe L50B and discharged from the cooling gas outlet pipe L51B, thereby circulating within the cooling gas piping of the purification unit 1B. In the 1B purification process, all normally open valves shown in Figure 2 are closed and all normally closed valves are opened, and purification is performed using the purification apparatus 1B.

[0051] Specifically, the pre-purification gas introduced into the pre-purification gas introduction pipe L10 passes through the normally closed valve V2 located in the branch pipe L12 and is introduced into the purification device 1B, where impurity gases are removed by the purifying agent. Since the normally open valve V1 is closed, the pre-purification gas does not flow into the purification device 1A. Also, since the normally open valve V4 is closed, the inert gas from the inert gas introduction pipe L20 does not flow into the purification device 1B.

[0052] The unpurified gas introduced into the purification unit 1B is purified and, as purified gas, passes through the normally closed valve V6 located in the branch pipe L32 and is discharged to the purified gas outlet pipe L30. Since the normally open valve V8 is closed, the purified gas does not flow into the discharge pipe L40. Also, since the normally open valve V5 is closed, the gas that flows out of the purification unit 1A is not discharged to the purified gas outlet pipe L30.

[0053] As described above, during the 1B purification process, the purification apparatus 1A is in the regeneration process, or in the regeneration process and the subsequent cooling process. During the regeneration process, the refining agent 50 in the refining apparatus 1A is heated by the heater 20, and the supply of cooling gas is stopped. In this state, all normally open valves shown in Figure 2 are closed, and all normally closed valves are opened, and the regeneration of the refining apparatus 1A is performed.

[0054] Specifically, the inert gas introduced into the inert gas introduction pipe L20 passes through the normally closed valve V3 located in the branch pipe L21 and is introduced into the purification unit 1A. Since the normally open valve V4 is closed, the inert gas does not flow into the purification unit 1B. Also, since the normally open valve V1 is closed, the pre-purification gas from the pre-purification gas introduction pipe L10 does not flow into the purification unit 1A.

[0055] The inert gas introduced into the purification unit 1A pushes out the impurity gases that have been separated from the purifying agent by heating with the heater 20. The pushed-out impurity gases, along with the inert gas, pass through the normally closed valve V7 located in the branch pipe L41 and are discharged from the discharge pipe L40. Since the normally open valve V5 is closed, the impurity gases and inert gas discharged from the purification unit 1A are not discharged into the purified gas outlet pipe L30. Also, since the normally open valve V8 is closed, the purified gas that flows out from the purification unit 1B is not discharged into the discharge pipe L40.

[0056] During the 1B purification process, when the cooling process is performed on the purification unit 1A following the regeneration process, the open / closed states of each normally open valve and normally closed valve are maintained as they were during the regeneration process, and the heater 20 of the purification unit 1A is stopped. In addition, cooling gas is introduced into the cooling gas inlet pipe L50A and discharged from the cooling gas outlet pipe L51A, thereby circulating the cooling gas within the cooling gas piping of the purification unit 1A. During the cooling process, the introduction of inert gas into the purification apparatus 1A may be stopped, but it is preferable to continue it in order to remove any trace amounts of adsorbed components remaining in the purification apparatus 1A.

[0057] <Other embodiments of semiconductor process gas purification systems> There are no particular limitations on the number of semiconductor process gas purification devices 1 of the present invention used in a semiconductor process gas purification system. One semiconductor process gas purification device may be used alone, or three or more semiconductor process gas purification devices 1 may be used in rotation. Alternatively, two or more semiconductor process gas purification devices 1 may be arranged in series. Furthermore, two or more semiconductor process gas purification devices 1 may be covered by a single heater 20.

[0058] There are no particular limitations on the type or positional relationship of valves installed on the piping. Not only valves that are switched open or closed by energizing, such as the normally open and normally closed valves in this embodiment, but also valves that can be switched open or closed manually are acceptable. Furthermore, a three-way valve or the like may be placed at a branching point, such as where the pre-purification gas introduction pipe L10 branches into branch pipes L11 and L12.

[0059] There are no particular limitations on the shape or arrangement of the piping. For example, in the embodiment shown in Figure 2, the downstream ends of branch pipe L11 and branch pipe L21 are shown to merge, but they may each be connected independently to the semiconductor process gas purification apparatus 1. The piping for the gas discharged from the semiconductor process gas purification apparatus 1 can also be any piping capable of discharging the purified gas and the inert gas, respectively.

[0060] In the regeneration process, the method for extracting the impurity gases removed from the purifying agent 50 is not limited to flowing an inert gas. For example, the impurity gases removed from the purifying agent 50 may be extracted from the downstream of the purified gas outlet pipe L30 or the discharge pipe L40 using a pump or the like. [Examples]

[0061] <Evaluation System> The purification capacity of the purification apparatus in each example and comparative example was evaluated using the evaluation system shown in Figure 3. In Figure 3, components similar to those in the semiconductor process gas purification system in Figure 2 are given the same reference numerals as in Figure 2, and their detailed explanations are omitted. The evaluation system in Figure 3 differs from the semiconductor process gas purification system in Figure 2 in that the downstream sides of branch pipes L12 and L22 and the upstream sides of branch pipes L32 and L42 are connected by bypass pipe L70, and it does not have a purification device 1B.

[0062] Furthermore, in the evaluation system shown in Figure 3, the downstream section of the purified gas outlet pipe L30 branches into branch pipes L61 and L62. The system also includes a Fourier transform infrared spectrophotometer (hereinafter sometimes referred to as "FT-IR device") 81 connected to branch pipe L61, a gas chromatograph (hereinafter sometimes referred to as "GC-FID device") 82 with a flame ionization detector connected to branch pipe L62, and a GC-FID device 83 connected to the discharge pipe L40.

[0063] <Example 1> As the purification apparatus 1A, a purification apparatus equipped with a spiral cooling gas pipe 30 was used, similar to the first embodiment in Figure 1. The inner diameter of the container body 11 was 41.6 mm, and the distance between the container end 12a and the container end 12b was 307.4 cm. The cooling gas piping 30 consisted of pipes with an outer diameter of 10.5 mm and an inner diameter of 6.5 mm. The outer diameter of the spiral section of the cooling gas piping 30 was 25.4 mm, and its length was 2425 mm. As the purifying agent 50 to be filled inside the container 10, MS13X manufactured by Nacalai Tesque was used. 1200g of this purifying agent 50 was filled into the container 10 so as to cover the cooling gas piping 30.

[0064] This purification apparatus was incorporated as purification apparatus 1A in Figure 3, and the 1A purification process and the 1A regeneration process were performed alternately. In the 1A purification process, the heater 20 was stopped, and the purifying agent was cooled by letting the cooling gas flow from the cooling gas inlet pipe L50A through the cooling gas piping 30 inside the purification apparatus 1A to the cooling gas outlet pipe L51A. In this state, all normally open valves were opened and all normally closed valves were closed, and the target gas was flowed through the pre-purification gas inlet pipe L10, and the inert gas was flowed through the inert gas inlet pipe L20.

[0065] The target gas used was boron trifluoride (BF3) gas containing carbon dioxide (CO2) as an impurity gas. Nitrogen gas was used as the inert gas. Nitrogen gas cooled to -30°C by a cooling device (not shown) was used as the cooling gas. The gases introduced into the pre-purification gas inlet pipe L10 or the inert gas inlet pipe L20 were flowed at a rate of 1 L / min.

[0066] The temperatures at temperature measurement points 61, 62, and 63 shown in Figure 1 were checked 15 hours after the start of the first 1A purification process (hereinafter sometimes referred to as "1A purification process 1") and 15 hours after the start of the second 1A purification process (hereinafter sometimes referred to as "1A purification process 2"). The results of the temperature measurements at the above measurement points are shown in Table 1.

[0067] In the 1A regeneration process, the introduction of cooling gas into the cooling gas inlet pipe L50A was stopped, and the purifying agent was heated by the heater 20. In this state, all normally open valves were closed, and all normally closed valves were opened, allowing the target gas to flow through the pre-purification gas inlet pipe L10 and the inert gas to flow through the inert gas inlet pipe L20. Table 1 shows the results of temperature measurements taken at the above measurement points 15 hours after the start of the first 1A regeneration process (hereinafter sometimes referred to as "1A regeneration process 1").

[0068] [Table 1]

[0069] During the 1A purification process, the concentration of boron trifluoride was measured using the FT-IR instrument 81, and the concentration of carbon dioxide was measured using the GC-FID instrument 82. During the 1A regeneration process, the concentration of boron trifluoride was measured using the FT-IR device 81, and the concentration of carbon dioxide was measured using the GC-FID device 83. The results are shown in Figure 4. The measurement conditions for the FT-IR device 81 and the GC-FID devices 82 and 83 were as follows.

[0070] [Measurement conditions for FT-IR device 81] Manufacturer: Horiba Stec Product name:FG-120 Detector: TGS Cell length: 1m Measurement temperature: 30℃ Measured pressure: 100 kPaA

[0071] [Measurement conditions for GC-FID device 82 and GC-FID device 83] Manufacturer: Shimadzu Corporation Product name:GC-8A Detector: Hydrogen salt ionization detector (FID) Detector temperature: 120℃ Column: Porapak T 50-80 Column temperature: 90℃ Sampling pressure: atmospheric pressure

[0072] <Example 2> For purification apparatus 1A, the same purification apparatus as in Example 1 was used, except that the cooling gas piping 30 was made straight. The cooling gas piping 30 had an outer diameter of 10.6 mm, an inner diameter of 6.5 mm, and a length of 525 mm. Aside from incorporating this purification apparatus as purification apparatus 1A in Figure 3, the 1A purification process and the 1A regeneration process were performed alternately, as in Example 1. Table 2 shows the temperature of the purified agent 50 measured under the same conditions as in Example 1, and Figure 5 shows the measurement results of the boron trifluoride concentration and carbon dioxide concentration.

[0073] [Table 2]

[0074] <Example 3> The same purification apparatus as in Example 2 was incorporated as purification apparatus 1A in Figure 3, and the cooling gas was cooled to -70°C by a cooling device (not shown). Otherwise, the 1A purification process and the 1A regeneration process were performed alternately, as in Example 1. Table 3 shows the temperature of the purified agent 50 measured under the same conditions as in Example 1, and Figure 6 shows the measurement results of the boron trifluoride concentration and carbon dioxide concentration.

[0075] [Table 3]

[0076] <Comparative Example 1> The same purification apparatus as in Example 1 was incorporated as purification apparatus 1A in Figure 3, but the experiment was conducted at room temperature without flowing a cooling gas. Otherwise, the 1A purification process and the 1A regeneration process were performed alternately, as in Example 1. Table 4 shows the temperature of the purified agent 50 measured under the same conditions as in Example 1, and Figure 7 shows the measurement results of the boron trifluoride concentration and carbon dioxide concentration.

[0077] [Table 4]

[0078] <Consideration> As shown in Figure 4, in the purification step 1A of Example 1, boron trifluoride with sufficient carbon dioxide removed was obtained. Furthermore, the purification efficiency hardly decreased even when the purification and regeneration steps were repeated.

[0079] Comparing Example 2, shown in Figure 5, with Example 1, shown in Figure 4, it was found that Example 1 had higher purification efficiency. Example 2 and Example 1 differ only in the shape of the cooling gas piping 30; in Example 2, it is linear, while in Example 1, it is spiral. Furthermore, the temperature of the purifying agent 50 15 hours after the start of the 1A purification process 1 in Example 2 was 0 to -30°C, while the temperature of the purifying agent 50 15 hours after the start of the 1A purification process 1 in Example 1 was -20 to -30°C. From this, it was found that a spiral cooling gas pipe 30 has a higher cooling capacity for the purifying agent than a straight cooling gas pipe 30, resulting in higher purification efficiency.

[0080] Comparing Example 3, shown in Figure 6, with Example 2, shown in Figure 5, it was found that Example 3 had higher purification efficiency. Examples 3 and 2 differ in the temperature of the cooling gas flowing through the cooling gas piping 30; the cooling gas temperature in Example 3 was -70°C, while the cooling gas temperature in Example 2 was -30°C. Furthermore, the temperature of the purifying agent 50 15 hours after the start of the 1A purification process 1 in Example 3 was -40 to -70°C, while the temperature of the purifying agent 50 15 hours after the start of the 1A purification process 1 in Example 2 was 0 to -30°C. This shows that even if the piping is straight, purification efficiency can be ensured by lowering the cooling gas temperature.

[0081] Comparing Example 3 shown in Figure 6 with Example 1 shown in Figure 4, it was found that Example 1 had higher purification efficiency. Examples 3 and 1 differ in the shape of the cooling gas piping 30; in Example 3, it is linear, while in Example 1, it is spiral. The temperature of the cooling gas also differs; in Example 3, the temperature of the cooling gas is -70°C, while in Example 1, it is -30°C. In Example 3, 15 hours after the start of the 1A purification process 1, the temperature of the purifying agent 50 was -40 to -70°C, while in Example 1, 15 hours after the start of the 1A purification process 1, the temperature of the purifying agent 50 was -20 to -30°C. From this, it was found that by making the cooling gas piping 30 spiral-shaped, the temperature of the cooling gas can be set higher without impairing the cooling capacity or purification efficiency.

[0082] In Comparative Example 1, shown in Figure 7, not only carbon dioxide but also boron trifluoride was removed during the purification process. Furthermore, compared to the other examples, the purification efficiency was low, and it was found that the purification efficiency decreased significantly when the purification and regeneration processes were repeated. In Comparative Example 1, the purifying agent 50 was not cooled with a cooling gas, and the temperature of the purifying agent 50 15 hours after the start of the 1A purification process 1 was 35-90°C. This indicates that purification efficiency is lower when the purification agent 50 is cooled compared to when it is purified. Furthermore, it was found that the purification efficiency decreases significantly when the purification and regeneration processes are repeated at room temperature. In addition, it was found that the purification agent 50 adsorbs not only carbon dioxide, which is an impurity gas, but also boron trifluoride, which is the target gas. [Explanation of symbols]

[0083] 1... Semiconductor process gas purification apparatus, 10... Container, 11... Container body, 12a, 12b... Container end, 20... Heater, 30... Cooling gas piping, 31... Cooling gas inlet connection, 32... Cooling gas outlet connection, 40... Pre-purification gas inlet connection, 41... Post-purification gas outlet connection, 42... Pre-purification gas inlet, 43... Post-purification gas outlet, 50... Purifying agent, 61, 62, 63... Temperature measurement points, 70... Bypass pipe, 81... FT- IR device, 82,83...GC-FID device, L10...Pre-purification gas inlet pipe, L20...Inert gas inlet pipe, L30...Post-purification gas outlet pipe, L40...Discharge pipe, L50A,L50B...Cooling gas inlet pipe, L51A ,L51B...Cooling gas outlet pipe, L11,L12,L21,L22,L31,L32,L41,L42,L61,L62...Branch pipe, V1,V4,V5,V8...Normally open valve, V2,V3,V6,V7...Normally closed valve

Claims

1. The device comprises a cylindrical container, a heater positioned to cover the outer surface of the container, and a cooling gas pipe passing through the inside of the container. The container is filled with a purifying agent for adsorbing impurity gases contained in the semiconductor process gas to be purified, and is provided with a pre-purification gas inlet and a post-purification gas outlet for passing the semiconductor process gas to be purified through and bringing it into contact with the purifying agent. A semiconductor process gas purification apparatus characterized in that the cooling gas piping is covered with the purifying agent inside the container.

2. The semiconductor process gas purification apparatus according to claim 1, wherein the cooling gas piping inside the container is spiral-shaped.

3. Furthermore, the semiconductor process gas purification apparatus according to claim 1 or 2, further comprising a cooling device for supplying cooling gas to the cooling gas piping.

4. The semiconductor process gas purification apparatus according to claim 1 or 2, wherein the purifying agent is an adsorbent having pores capable of adsorbing the impurity gas.

5. A method for purifying a semiconductor process gas, comprising the steps of purifying the semiconductor process gas to be purified by contacting it with a cooled purifying agent to adsorb impurity gases, and regenerating the purifying agent by heating it to remove the desorbed impurity gases and then pushing them out with an inert gas.

6. The semiconductor process gas purification method according to claim 5, wherein the purifying agent is an adsorbent having pores capable of adsorbing the impurity gas.

7. The semiconductor process gas purification method according to claim 6, wherein the semiconductor process gas to be purified is a gas selected from the group consisting of halogen gases, halides, and hydrides.

8. The semiconductor process gas purification method according to claim 7, wherein the semiconductor process gas to be purified is selected from the group consisting of boron trifluoride, phosphorus trifluoride, chlorine trifluoride, fluorine, hydrogen fluoride, chlorine, hydrogen chloride, carbonyl sulfide, and hydrazine.

Images