JP2004241472A - Gas treatment apparatus and method therefor and method of manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas treatment apparatus and a method having an excellent decomposition capability of reactive elements in the gas and also provide a method of manufacturing semiconductor device. <P>SOLUTION: The gas treatment apparatus comprises a plasma decomposition apparatus 26 for decomposing the reactive elements included in the gas and pumps 25, 27 which are connected to the plasma decomposition apparatus 26 to set the gas to the evacuated state. To the plasma decomposing apparatus 26, the added gas which can react with the reactive elements is introduced and the added gas includes ozone. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a gas processing apparatus, a gas processing method, and a method for manufacturing a semiconductor device.
[0002]
[Background Art]
As one of devices for decomposing gaseous reactive components, a plasma decomposition device is used. This plasma decomposition apparatus can decompose an organic halogenated compound such as a PFC (perfluoro-compounds) gas or a CFC (chlorofluoro-compounds) gas into a lower molecular gas. These gases (organic halide compounds) are known as so-called greenhouse gases. This greenhouse gas is said to be a causative substance of global warming. In order to control the progress of global warming, there is an international need to minimize the emission of these gases into the atmosphere.
[0003]
In addition, the above-mentioned gases have been conventionally used as a coolant for refrigerators, air conditioners, automobiles, and the like, and it is a serious problem that these gases are released into the atmosphere when these devices are disposed of. ing. The above-mentioned gases are also used in the process of manufacturing a semiconductor device, and it is required to appropriately treat these gases after use. Therefore, as described above, a processing method using a plasma decomposition device is used as one of the means for decomposing the gas. The plasma decomposition apparatus is also widely used as a means for decomposing harmful substances other than the above-mentioned gas.
[0004]
As a general plasma decomposition apparatus, there is, for example, the following.
[0005]
[Patent Document 1]
JP-A-2001-274000 (FIGS. 9 and 10).
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a gas processing apparatus, a gas processing method, and a method for manufacturing a semiconductor device having an excellent ability to decompose reactive components in a gas.
[0007]
[Means for Solving the Problems]
1. Gas processing device The gas processing device of the present invention is a plasma decomposition device that decomposes a reactive component contained in a gas,
A pump connected to the plasma decomposition apparatus to bring the gas into a reduced pressure state,
An additive gas capable of reacting with the reactive component is introduced into the plasma decomposition device,
The additive gas contains ozone.
[0008]
Here, the “reactive component” refers to a component that reacts in the plasma decomposition apparatus, and the “gas containing a reactive component” means that a part of the component contained in the gas is a reactive component. In addition to the gas, the gas contains only a reactive component.
[0009]
Ozone is a highly reactive substance. Therefore, according to the gas processing apparatus of the present invention, the decomposability of the reactive component can be enhanced in the plasma decomposition because the additional gas contains ozone. As a result, the ability of the plasma decomposition apparatus to decompose gas can be increased. In addition, ozone decomposes relatively quickly because of its high reactivity. Therefore, post-treatment of the waste gas after the plasma decomposition is easy. As a result, the cost required for the post-processing can be reduced. Further, since ozone has high reactivity and ozone has a larger number of oxygen atoms per unit molecule than, for example, oxygen gas, the amount used in the plasma decomposition is reduced as compared with oxygen gas. be able to. Thereby, the flow rate of the additional gas can be reduced, so that a change in the pressure in the plasma decomposition apparatus due to the introduction of the additional gas can be reduced. Thereby, the plasma decomposition apparatus can be operated stably.
[0010]
In this case, the additive gas may further include water. Thereby, in the plasma decomposition, the decomposability of the reactive component can be further increased. As a result, the gas decomposition capability of the plasma decomposition device can be further improved.
[0011]
In this case, the ozone and water can be obtained by vaporizing ozone water. According to the gas treatment apparatus of the present invention, the ozone water can be easily vaporized because the gas is set in a reduced pressure state by the pump. Thus, the ozone and water can be introduced into the plasma decomposition device by a simple method.
[0012]
2. Gas Treatment Method The gas treatment method of the present invention is a gas treatment method for decomposing a reactive component contained in a gas under reduced pressure, and includes plasma decomposing the reactive component in the presence of ozone.
[0013]
Ozone is a highly reactive substance. Therefore, according to the gas processing method of the present invention, the decomposability of the reactive component can be increased by subjecting the reactive component to plasma decomposition in the presence of ozone. In addition, since ozone decomposes relatively quickly, post-treatment of the waste gas after the plasma decomposition is easy. Therefore, the cost required for the post-processing can be reduced.
[0014]
In this case, the plasma decomposition can be performed in the presence of ozone and water. Thereby, in the plasma decomposition, the decomposability of the reactive component can be further increased.
[0015]
In this case, the ozone and water can be obtained by vaporizing ozone water. According to the gas processing method of the present invention, since the plasma decomposition is performed under reduced pressure, the ozone water can be easily vaporized.
[0016]
3. Semiconductor Device Manufacturing Method The gas processing apparatus and the gas processing method of the present invention can be applied to a semiconductor device manufacturing method.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0018]
1. FIG. 1 is a schematic configuration diagram of a gas processing apparatus 100 according to an embodiment to which the present invention is applied.
[0019]
The gas processing apparatus 100 of the present embodiment has a function of decomposing a reactive component in a gas by the plasma decomposition apparatus 26. Specifically, the gas processing apparatus 100 includes a turbo pump 25, a plasma decomposition device 26, and a dry pump 27, as shown in FIG. The turbo pump 25 is adjacent to the reactor 22. The plasma decomposition device 26 is disposed between the turbo pump 25 and the dry pump 27. More specifically, the turbo pump 25 and the plasma decomposition device 26 are connected via a pipe 92, and the plasma decomposition device 26 and the dry pump 27 are connected via a pipe 96.
[0020]
In the present embodiment, a case where the reactive component is PFC will be described. In this embodiment, a case where the gas treatment apparatus is used in a semiconductor device manufacturing process will be described. Specifically, in the semiconductor device manufacturing process, after a reaction using PFC is performed in the reactor 22, a gas containing unreacted PFC and a fluorinated compound generated by the reaction as a reactive component is generated. Is discharged from the reaction device 22. After the gas is introduced into the plasma decomposition device 26, the reactive components in the gas are decomposed in the plasma decomposition device 26.
[0021]
The turbo pump 25 and the dry pump 27 have a function of reducing the pressure of the gas in the plasma decomposition device 26.
[0022]
In order for the reactive components (PFC and fluorinated compound) to be efficiently plasma-decomposed in the plasma decomposition device 26, it is desirable that the gas pressure in the plasma decomposition device 26 be set to an appropriate range. The appropriate pressure range of the gas depends on the type and concentration of each reactive component contained in the gas, the temperature in the plasma decomposition device 26, and the like. If the pressure of the gas in the plasma decomposition device 26 is too low, collisions between the molecules constituting the reactive component and the plasma hardly occur. As a result, plasma decomposition becomes difficult to occur, and the plasma decomposition efficiency may be reduced. On the other hand, if the pressure of the gas in the plasma decomposition device 26 is too high, sufficient plasma for decomposing the reactive component contained in the gas cannot be obtained, and the plasma decomposition efficiency may be reduced.
[0023]
According to the gas processing apparatus 100 of the present embodiment, the gas pressure in the plasma decomposition apparatus 26 is adjusted to an appropriate range by the turbo pump 25 and the dry pump 27, so that The decomposition efficiency of the reactive component can be increased.
[0024]
In the reactor 22, PFC is used in a semiconductor device manufacturing process such as dry etching or CVD. Specifically, as shown in FIG. 1, PFC is introduced into the reactor 22 from the gas inlet 36. Then, as a result of the reaction in the reaction device 22, a gas containing unreacted PFC and a fluorinated compound generated by the reaction as a reactive component is discharged to the turbo pump 25.
[0025]
The turbo pump 25 is connected to the reaction device 22. Specifically, after introducing the gas discharged from the reaction device 22, the turbo pump 25 reduces the pressure of the gas until a high vacuum state is reached. The dry pump 27 is connected to the plasma decomposition device 26. The dry pump 27 adjusts the pressure of the gas discharged from the plasma decomposition device 26.
[0026]
In the present embodiment, the case where the turbo pump 25 and the dry pump 27 are used as means for reducing the pressure of the gas in the plasma decomposition device 26 has been described, but the gas in the plasma decomposition device 26 may be reduced in pressure. If possible, the means for decompressing the plasma decomposition device 26 is not limited to these.
[0027]
The plasma decomposition device 26 is a low-pressure discharge plasma type plasma decomposition device. 2. Description of the Related Art In a plasma decomposition apparatus of a reduced pressure discharge plasma type, it is required that a gas introduced into the plasma decomposition apparatus be reduced in pressure in order to generate discharge plasma. Therefore, it is necessary to install a decompression device (here, the turbo pump 25 and the dry pump 27). The plasma decomposition apparatus of the reduced pressure discharge plasma type has a characteristic that organic gas can be efficiently decomposed at a relatively low temperature. Examples of the plasma decomposition apparatus 26 include an apparatus using an inductively coupled plasma (ICP) method or an RF (parallel plate type) method, depending on the plasma generation method.
[0028]
The plasma decomposition device 26 decomposes the reactive components (unreacted PFC and fluorinated compound) contained in the gas discharged from the turbo pump 25. Further, the gas discharged from the turbo pump 25 is introduced into the plasma decomposition device 26, and an additive gas is introduced from an additive gas inlet 38. This added gas is used to react with the reactive component in the plasma decomposition device 26.
[0029]
Specifically, as shown in FIG. 1, the turbo pump 25 and the plasma decomposition device 26 are connected by a pipe 92, and a pipe 94 is connected in the middle of the pipe 92. Thereby, the additional gas can be introduced into the plasma decomposition device 26 together with the gas discharged from the turbo pump 25.
[0030]
The additive gas contains ozone. Ozone has excellent reactivity with various compounds. Therefore, in the plasma decomposition apparatus 26, by using a gas containing ozone as an additional gas, the reactive components (PFC and fluorinated compounds) contained in the gas discharged from the turbo pump 25 can be converted into CO ₂ or CO and H It can be easily decomposed into ₂ O, F _{2 and the} like. Therefore, according to the gas processing apparatus 100 of the present embodiment, the decomposability of the reactive component can be improved in the plasma decomposition in the plasma decomposition apparatus 26 by including the ozone in the additional gas. As a result, the ability of the plasma decomposition device 26 to decompose gas can be increased.
[0031]
In addition, ozone decomposes relatively quickly because of its high reactivity. Therefore, post-treatment of the waste gas after the plasma decomposition is easy. As a result, the cost required for the post-processing can be reduced.
[0032]
In addition, ozone has high reactivity, and ozone has a larger number of oxygen atoms per unit molecule than, for example, oxygen gas, so the amount used in the plasma decomposition is reduced as compared with oxygen gas. can do. Thereby, the flow rate of the additional gas can be reduced, so that a change in the pressure in the plasma decomposition device 26 due to the introduction of the additional gas can be reduced. Thereby, the plasma decomposition device 26 can be operated stably. As the additional gas, a gas which is inactive with respect to the reactive component such as nitrogen or argon and contains ozone can be used.
[0033]
For example, when an additional gas containing ozone is introduced into the plasma decomposition device 26 together with a gas containing C ₂ F ₆ (a kind of PFC) as the reactive component, for example, C ₂ F ₆ The reaction of + 2 / 3O ₃ → 2CO + 3F ₂ proceeds. That is, C ₂ F ₆ is converted into carbon monoxide gas (CO) and fluorine gas (F ₂ ) after being decomposed.
[0034]
Further, the additive gas may include water in addition to ozone. In this case, the decomposability of the reactive component in the plasma decomposition can be further enhanced. Specifically, the substance obtained after the decomposition can be converted into post-carbon dioxide gas (CO ₂ ) and hydrogen fluoride (HF) by including water in the additive gas. HF is compared to F _2, it has the advantage that more post-processing is easy. Thereby, the post-treatment of the gas obtained after the reaction can be further facilitated by the fact that the additive gas further contains water.
[0035]
In this case, ozone and water contained in the additive gas can be produced by vaporizing ozone water. In this case, since the inside of the pipe 94 is set in a reduced pressure state, the ozone water can be easily vaporized by introducing liquid ozone water from the additional gas inlet 38. As a result, ozone water can be easily introduced into the plasma decomposition device 26. Further, the liquid ozone water may be boiled and vaporized. Alternatively, the ozone water can be vaporized by directly injecting liquid ozone water from the additive gas inlet 38.
[0036]
Ozone water is used as cleaning water for removing, for example, metal impurities and organic substances (eg, resist) in a semiconductor device manufacturing process. When an ozone water line is already installed in a semiconductor device manufacturing line, ozone water can be easily introduced from the ozone water line. Therefore, there is no need to provide new equipment for producing ozone water, which is economical.
[0037]
Further, a means for removing an acidic gas (for example, F ₂ or HF) before discharging the gas from the sub pump 28 can be provided. Examples of the method for removing the acidic gas include (i) a method in which the gas is reacted by bubbling the gas with an alkaline aqueous solution, (ii) a method in which the gas is passed through an adsorbent, or (iii) a method in which the gas is burned. Is decomposed.
[0038]
2. Next, the operation of the gas processing apparatus 100 will be described.
[0039]
The gas discharged from the reactor 22 is introduced into a turbo pump 25. The gas discharged from the reactor 22 contains unreacted PFC and fluorinated compounds as the reactive components.
[0040]
Next, these gases introduced into the turbo pump 25 are discharged by the turbo pump 25 after the pressure is reduced to a predetermined pressure at which a high vacuum state is obtained. The gas discharged here is introduced into the plasma decomposition device 26 through the pipe 92. Here, the additive gas is introduced into the plasma decomposition device 26 from the additive gas inlet 38 through the pipes 94 and 92. In the plasma decomposition device 26, the reactive component is decomposed by the plasma and reacts with the additive gas (see the example of C ₂ F ₆ described above). As a result, unreacted PFC and fluorinated compounds are converted into lower-molecular gases (CO, CO ₂ , H ₂ O, F ₂ , HF, etc.).
[0041]
Next, after the gas after the reaction is discharged from the plasma decomposition device 26, the gas is introduced into the dry pump 27 through the pipe 96. The pressure of the gas introduced into the dry pump 27 is further adjusted by the dry pump 27. Thereafter, the gas is discharged from the dry pump 27 and then discharged from the gas discharge port 34 through the pipe 99. Among the gas discharged here, the acidic gas can be removed by the above-described method.
[0042]
The present invention is not limited to the embodiments described above, and various modifications are possible. For example, the invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, a configuration with the same function, method, and result, or a configuration with the same object and result). Further, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. Further, the invention includes a configuration having the same operation and effect as the configuration described in the embodiment, or a configuration capable of achieving the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.
[0043]
For example, in this embodiment, the case where the plasma decomposition apparatus decomposes PFC has been described as an example. However, the substance decomposed by the plasma decomposition apparatus is not limited to PFC. The first reactive component-containing gas may be used.
[0044]
Further, in the present embodiment, the case where the gas processing apparatus and the gas processing method of the present invention are used in a semiconductor device manufacturing process has been described. Gas treatment methods can be used. Other uses include, for example, the removal of harmful substances from gases emitted from product painting plants, solvent handling facilities, printing plants, automotive painting plants, gas stations and other establishments. In this case, the gas contains the harmful substance as a reactive component. Also, it goes without saying that any component that is reactive to the additive gas, even if it is not a harmful substance, can be decomposed by the gas processing apparatus and the gas processing method of the present invention.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a gas processing apparatus according to an embodiment of the present invention.
[Explanation of symbols]
22 reactor, 25 turbo pump, 26 plasma decomposition device, 27 dry pump, 34 gas outlet, 36 gas inlet, 38 additive gas inlet, 92, 94, 96, 99 piping, 100 gas processing device

Claims (8)

A plasma decomposition device that decomposes a reactive component contained in a gas, and a pump connected to the plasma decomposition device and for bringing the gas into a reduced pressure state,
An additive gas capable of reacting with the reactive component is introduced into the plasma decomposition device,
The gas processing device, wherein the additive gas includes ozone. In claim 1,
The gas treatment device, wherein the additive gas further includes water. In claim 2,
A gas treatment device, wherein the ozone and water are obtained by vaporizing ozone water. A method for manufacturing a semiconductor device using the gas processing apparatus according to claim 1. A gas processing method for plasma-decomposing a reactive component contained in a gas under reduced pressure,
A gas processing method, comprising plasma-decomposing the reactive component in the presence of ozone. In claim 5,
A gas processing method, wherein the plasma decomposition is performed in the presence of ozone and water. In claim 6,
A gas processing method, wherein the ozone and water are obtained by vaporizing ozone water. A method for manufacturing a semiconductor device using the gas processing method according to claim 4.

Images