WO1996004064A1

WO1996004064A1 - Hydride gas removing method and apparatus

Info

Publication number: WO1996004064A1
Application number: PCT/JP1995/001553
Authority: WO
Inventors: Tadahiro Ohmi
Original assignee: Tadahiro Ohmi
Priority date: 1994-08-05
Filing date: 1995-08-04
Publication date: 1996-02-15
Also published as: KR970704501A; JP3801201B2; JPH09239232A

Abstract

Hydride gas removing method and apparatus which are capable of detoxifying a mixed gas by completely removing various hydride gases therefrom by using a simple structure without generating pulverized bodies which would cause the clogging of the apparatus. The method is characterized in that a mixed gas containing at least two kinds of hydride gases is brought into contact with nickel fluoride and nickel to subject the hydride gases to decomposition or/and adsorption, whereby the hydride gases are removed. The method is also characterized in that a gas of a hydride of a group III or V element in the periodic table is removed by bringing the gas into contact with nickel so as to subject the gas to decomposition or/and adsorption, whereby the hydride gas is removed.

Description

Description Method and apparatus for removing hydride gas

The present invention relates to a method and an apparatus for removing a hydride gas, and more particularly to a method and an apparatus for removing a dangerous and toxic hydride gas used in a semiconductor manufacturing process. Background art

Hydride gases, such as silane, phosphine, diborane, and arsine, used in the semiconductor manufacturing process are self-combustible and toxic. Therefore, it is necessary to completely remove unreacted gases to make them harmless before discharging them to the atmosphere.

These gas removal methods include a dry removal method in which gas is removed through a packed column in which a porous carrier and an oxidizing agent are supported (Japanese Patent Laid-Open Publication No. 3-137917), and a liquid removal method. There are known wet removal methods of absorbing by gas-liquid contact, neutralizing and decomposing and removing (JP-A-4-59017 and JP-A-4-310215). You.

However, in these methods, for example, silane gas is decomposed into a solid powder such as Sio ₂ , so that there are many problems in management and maintenance, such as clogging of a packed tower. In addition, various methods and devices have been proposed to solve this obstacle, but none of these methods is sufficient, and the devices have been complicated and large. Another problem with the dry removal method is that it is not possible to remove all hydride gases because of its selectivity for removal.

Furthermore, these conventional removal devices treat the gas discharged from the vacuum exhaust pump, and cannot be disposed inside the vacuum due to the configuration, so that the hydride gas in the vacuum system upstream of the exhaust pump is removed. It is difficult to deal with various adverse effects caused by decomposition. For example, unreacted gas self-decomposes or reacts between the reaction chamber and the vacuum pump, and the reaction product adheres to the piping or the vacuum pump, resulting in a significant decrease in the suction capacity of the pump. In addition, the balance of the pump rotating blades is lost And so on. Therefore, it is necessary to periodically disassemble and clean the pump, etc., but since the attachment itself is still flammable and toxic, the disassembly and cleaning work is also extremely dangerous. Under such circumstances, there is a demand for a hydride gas removal apparatus having a simple structure that can be easily maintained without clogging due to generation of powders and the like and that can be installed in a vacuum system.

The present invention provides a method and an apparatus for removing a hydride gas capable of completely removing a mixed gas containing a plurality of hydride gases and rendering the mixture harmless with a simple configuration without clogging due to powder generation. The purpose is to do. It is another object of the present invention to provide a method and an apparatus for removing a hydride gas which can be disposed in a vacuum system with a simple configuration and which facilitates maintenance of a hydride gas use apparatus. Disclosure of the invention

The hydride gas removing method of the present invention comprises removing a hydride gas by bringing a mixed gas containing at least two or more hydride gases into contact with nickel fluoride and nigel to decompose or adsorb the mixed gas. It is characterized by.

Further, the hydride gas is a hydride gas of an element belonging to Group IV, IV, or V of the periodic table.

In the present invention, the hydride gas is preferably decomposed and removed by heating the nickel fluoride and the nickel, and more preferably the nickel fluoride and the Nigel are heated to different temperatures. ,.

Further, the method for removing a hydride gas of the present invention is characterized in that a hydride gas of a Group III element or a Group V element of the periodic table is brought into contact with nickel to decompose and / or adsorb the hydride gas. Is removed. Further, it is preferable that the hydride gas be decomposed and removed by heating the nickel.

The hydride gas removing device of the present invention has at least one container having an inlet and an outlet for a mixed gas containing at least two or more hydride gases, and contacts the mixed gas in the container. In this case, the nickel fluoride and the nigger are separately arranged so that the nickel fluoride and the nigger are separately arranged, and a heating means for heating the nickel fluoride and the nigger is provided. The heating means is configured to heat the nickel fluoride and the nickel gel to different temperatures.

Further, the hydride gas removing apparatus of the present invention includes: a container having an inlet and an outlet for a mixed gas containing a hydride gas of a Group III element or a Group V element of the periodic table; Nickel is provided so as to be in contact with the battery, and a heating means for heating the nickel is provided. Action

Hereinafter, the operation of the present invention will be described with reference to experiments.

The present inventor has found that, among various materials, nickel fluoride, in particular, exhibits excellent decomposition characteristics with respect to silane. Silane can be decomposed at a low temperature. As a result, it is possible to remove silane by installing a pipe coated with nickel fluoride on the upstream side of the vacuum pump, preventing powder generation and adhesion inside the pump, and maintaining the entire equipment. It became very easy.

On the other hand, in a semiconductor manufacturing process, for example, a film forming process of a semiconductor film, a gas such as phosphine, arsine, or diborane is introduced simultaneously with silane in order to control conductivity. All ^ <gaseous gases in these gas mixtures are dangerous and highly toxic, and must be completely removed and exhausted. However, if the treatment of the mixed gas of silane and phosphine is to be removed with the above nickel fluoride, it is necessary to heat to a high temperature of 300 ° C. or more in order to decompose phosphine by 100%. i F ₄ ends up occurring in a mixed gas type secondary Kkerufu' to use a product may see that there is a limit ivy o

Thus, the present inventors have conducted intensive studies to solve this problem, and as a result, the metal Ni has a high adsorption capacity for hydride gas of the group III element and the group V element of the periodic table and decomposes. It has a high accelerating effect. In particular, phosphine can be decomposed 100% at a low temperature of about 50 ° C.

The present invention has been completed based on these findings, and uses nickel fluoride and Nigel to remove a mixed gas of two or more hydride gases at a low temperature. It becomes possible to do.

When nickel fluoride and nickel are brought into contact with a hydride-based gas, the hydride gas generates an equivalent amount of hydrogen gas and is decomposed. For this reason, it is possible to prevent problems such as the conventional problems caused by the solid product, that is, the adhesion of the reaction product to the pump and the clogging of the packed tower. The amount of hydride gas treatment per nickel fluoride or nickel unit surface area is considered to be the amount by which elements such as Si, P, and B generated by decomposition cover the nickel fluoride and nickel surface. In fact, much more hydride gas can be processed than this amount. The reason for this is not clear at present, but it is presumed that even if Si, P, B, etc. cover the surface, Ni diffuses to the surface and the decomposition ability is maintained.

In addition, even small amounts of Group II and Group V elements in the periodic table have a significant effect on semiconductor quenching. Therefore, as described above, Ni has a high ability to adsorb hydride gases of Group III and V elements of the Periodic Table, and by using this characteristic, Ni can adsorb and remove trace hydride gases in various gases. Thus, the gas can be highly purified.

Hereinafter, the operation of the present invention will be described in more detail with reference to experiments performed in the course of the present invention.

(Experimental example 1)

Using the measurement system shown in Fig. 1, hydride gas removal pipes (1Z 4-inch pipes with a length of lm) having various inner surfaces were heated to a predetermined temperature, silane gas was flown, and the decomposition characteristics were examined. Was.

In FIG. 1, a specific hydride gas is introduced into the hydride gas removal pipe 1 and processed by adjusting a mass flow controller (MFC) and a valve for various hydride gases. Then, it is sent to the cell 12 of a Fourier transform infrared spectrometer (FTIR), where the silane concentration in the gas is measured. The gas discharged from the cell 12 is sent to the gas chromatography 13 where the H ₂ gas concentration is analyzed. Although not shown in the figure, a heater for heating is arranged around the hydride gas removing pipe 11, whereby the gas removing pipe 11 can be heated to a predetermined temperature.

Fig. 1 (b) is an enlarged view of cell 2, where Ar gas is used to protect the window material (KBr). b

It is a structure to be introduced.

When 100 scpm of silane gas (Ar gas dilution) is flowed through the hydride gas removal pipe 11 at 5 sccm, the change in silane concentration in the discharged gas with respect to the heating temperature is shown in Fig. 2 (a). As the removal tubes, N i F ₂ tubes, pure N i pipe, Hasuteroi electropolished tube, SUS 3 1 6 L electropolished tube, using C r ₂ 0 ₃ tube. The Ni F ₂ pipe is formed by applying a fluorine gas to the inner surface of the Ni pipe to form a 0.2 ^ 111 1 ^ 1 F ₂ film. Also, C r ₂ 0 ₃ tube, H. on the inner surface of the SUS 316 L electropolished tube l 0%, is 0 ₂ 50 p pm introducing A r gas containing heating oxidation at 500, that form a C r ₂ 0 ₃ unmoving film on the surface.

As apparent from FIG. 2 (a), N i F 2 tubes showed the most excellent decomposition properties, C r ₂ 0 ₃ tube hardly show any activity of promoting degradation, also decrease the content of N i is a metal It was found that the decomposition characteristics deteriorated as the temperature increased.

Also, it is shown in FIG. 1 (b) the results of the H ₂ gas concentration in the exhaust gas was analyzed by Gasuku port Matogurafi 3 having the heat conduction type detector (TCD). Hydrogen 'Minatodo As shown in FIG reached 200 p pm at a temperature range of, silane was found to generate a completely decomposed to equivalents of H _n gas. When heated to higher temperatures, the silane concentration in the exhaust gas remained at zero, although the hydrogen gas flow was reduced (the reason is currently unknown). In the case of a N i F ₂ tube, FT IR measurement results show that heating to about 220 ° C or more generates S i, and when using Ni F ₂ , a temperature of 200 ° C or less Need to be

(Experimental example 2)

In the same manner as in Experimental Example _{_{1, PH 3, B 2 H}} 6 and AsH ₃ the results of examining the degradation characteristics of the gas removal pipe of various materials to the gas in FIG. 3, 4 and 10, also minimum of 100% degradation Table 1 shows the temperatures. Incidentally, the table, in Fig, F e ₂ 0 ₃ phrase is heated oxidized by introducing A r gas containing 30% 0 ₂ in SUS 315 L electropolished tube 425 ° C, the inner surface F e ₂ 0 ₃ film is obtained by 20 nm formed. Si is obtained by flowing Si gas through the inner surface of a SUS 316L electropolishing tube, thermally decomposing it at 480 ° C to form a silicon film of 30 nm, and then flowing H ₂ to process it. S I_〇 ₂ are those wherein the oxidation of the surface at 600 by introducing 0 ₂ S i surface. Other The same as in Experimental Example 1.

As is apparent from chart or table, having a decomposition characteristic N i tube is excellent, especially PH. AsH ₃ or the like degrades completely PH ₃ at a low temperature of 50 ° C for gas, extremely with high decomposition It has been found to have properties. Further, for example, N i F Pho must be heated above 300 ° C and you'll decompose and remove in ₂ tube and generating a S i F ₄ in this temperature as described above, N i F ₂ alone in was found that not suitable for removal of a gas mixture of S i and PH _3.

(Experimental example 3)

Using the measurement system of Figure 1, at room temperature (25 ° C) with B ₂ H _6, PH ₃ gas is flowed to the pipe for various gas removal was examined a change with time of the concentration. The changes in B ₂ H ₆ and PH ₃ gas concentrations are shown in FIGS. 5 and 6, and the adsorption molecular weight calculated from the figures is shown in Table 1.

As shown in the figure or table, it was found that the Ni tube has a higher adsorption capacity for B ₂ H ₆ and PH ₃ gas than other tubes, and can adsorb and remove the gas for a long time. Therefore, it is possible to purify other gases containing a small amount of hydride gas, and this is an extremely useful purification method especially when the gas is thermally unstable.

【table 1】

1 ■ "1

1 ^B 2 ^H 6 ¹

1 1 1 1 1

1 SUS ^Fe 2 ° 3 1 ^Cr 2 ° 3 ¹ Si 1 Si0 ₂ 1 Ni 1

1 Number of adsorbed molecules 1 2.4 3.0 1 3.0 1 0 1 4.2 1 5.41 1 1 (/ cm ² ) 1 xlO ¹⁴ xlO ¹⁴ 1 xl0 ¹⁴ | 1 xlO ¹⁴ X10 ¹⁴ |

1100% power decomposition 1 250 150 1 240 1 160 1 180 125 1

1 temperature (.C)

1 1 1 1

1 PH ₃ 1

1 ■ '' 1 1 1 1 1 i 1 SUS I ^Fe 2 ° 3 ^{1 Cr} 2 ° 3 Si 1 Si0 ₂ 1 Ni 1

1 Number of adsorbed molecules 0 1 1.8 1 0 0 1 0 1 1.62 1

1 (/ cm ² ) 1 xl0 ¹⁴ | 1 xlO ¹⁵ 1

1100% force decomposition 260 1 210 1 370 490 1 505 1 55 1

1 Temperature (° C)

1 1 1 1 1 1 The nickel fluoride used in the present invention is preferably Ni F ₀ having a stoichiometric ratio from the viewpoint of the ability to decompose hydride gas, but is not limited thereto. For Nigel, pure nickel is preferable, but an alloy containing nickel may be used. As a method of arranging these Nigel and nickel fluoride in contact with a hydride gas, the piping and the container itself should be used. It is possible to introduce a hydride gas into the inside of the container by arranging it in the container as a tube, mesh, fiber, or pellet having a small diameter. Alternatively, the inner surface of a stainless steel pipe, vessel, or the like may be coated with a nickel fluoride film, or may be coated on a solid surface of another material of the above-mentioned shape. As the solid, F e, N i, C r, SUS , etc. Various metals, other _{alloys, A 1 o0 3, AIN,} S i C such as a ceramic or the like is preferably used. Examples of a method of coating a fluoride on a nickel or nickel fluoride film with a solid include a plating method, a sputtered film, and vapor deposition. As the nickel fluoride, one obtained by fluorinating nickel is particularly preferably used.

To perform the fluoridation treatment, for example, Ni tube or this is subjected to Ni-P (nickel-phosphorus) plating of about 10 / m thickness by an electroless plating method, and fluorine gas is applied to the plating film at 350 ° C. By acting, a NiF ₂ film of about 0.2 / zm may be formed.

In the present invention, when the hydride gas is decomposed and removed, it is preferable to heat from the viewpoint of the decomposition efficiency. Preferred heating temperatures are: hydride type, flow rate, pressure, contact area of nigel and nickel fluoride gas, nickel and nickel fluoride It is appropriately optimized depending on the arrangement and the like, but when nickel and nickel fluoride are arranged at the same place, the temperature is preferably 85 to 200 ° C. It is more preferable to place nickel and nickel fluoride in different places and heat them to their respective optimum temperatures. The preferable temperature at this time is 50 to 300 for nickel. C, nickel fluoride is 85 ~ 200 ° C.

In the present invention, when a large amount of hydrogenated gas is treated, a method of coating the surface of a pellet-like granular solid with nickel or nickel fluoride, filling the pellets or the like into a packed tower, and subjecting the pellets or the like to the treatment is performed. Is effective.

Examples of the hydride gas to which the present invention is applied include a hydride gas of a Group III element such as B ₂ H ₆ , a hydride gas of a Group V element such as PH ₃ and As H ₀ , and S _{i H ^. S i 2 H} 6, G e H 4 group IV elements of the hydride gas and mixed gas, etc., such as are exemplified up. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a conceptual diagram showing an experimental apparatus for examining the hydride gas removal ability of the present invention.

Figure 2 is a graph showing the effect of temperature on silane decomposition and H ₂ gas generation for various materials.

Figure 3 is a graph showing the relationship between the decomposition of diborane and the temperature for various materials. Figure 4 is a graph showing the relationship between phosphine decomposition and temperature for various materials.

FIG. 5 is a graph showing the phosphine adsorption ability of various materials.

FIG. 6 is a graph showing the diborane adsorption capacity of various materials.

FIG. 7 is a conceptual diagram illustrating an arrangement of the removing device according to the first embodiment.

FIG. 8 is a conceptual diagram illustrating an arrangement of the removing device according to the second embodiment.

FIG. 9 is a conceptual diagram illustrating an arrangement of the removing device according to the third embodiment.

FIG. 10 is a graph showing the relationship between the decomposition rate of arsine and temperature for various materials.

(Explanation of code) 1 1 Hydride gas removal pipe,

12 FT I R cell,

13 Gas chromatography,

71, 81 Reaction chamber one,

72, 82 piping,

73, 83, 83 'hydride gas removal equipment,

74.84 Turbo molecular pump,

75, 85 rotary pump,

76, 86, 86 'heater,

91 hydride gas inlet,

92, 92 'Packed tower filled with nickel membrane or carrier coated with nickel fluoride

93 heater,

94 gas detector,

95 washing tower,

96 water circulation tank,

97 Water circulation pump. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

(Example 1)

FIG. 7 shows a first embodiment of the present invention.

FIG. 7 shows an example in which the removing device is arranged between the reaction chamber of the semiconductor manufacturing apparatus and the vacuum pump. In FIG 7, 7 1 reaction chamber one, 72 pipe, 73 gas removal apparatus using an N i F _2, 74 is a turbo-molecular pump, 75 is a rotary pump, 76 denotes a heater.

Here, the hydride gas remover is a 4 mm diameter cylindrical vessel with a diameter of 40 cm in order to facilitate hydride catalytic decomposition and minimize equipment resistance. A 60 cm Ni tube and a tube of the same shape having _two layers of Ni F formed on the surface, which were inserted into a honeycomb structure, were used.

Using this device, n ⁺ polysilicon _{(5% S i H 4 1} s 1 m, 0. 5% PH 3 2 s 1 m, A rl O slm) 4 0 0 nm of deposition and PSG (5% S i H ₄ (N ₂ dilution) 800 sc cm, 5% PH 3 (N 2 dilution) repeatedly performed 1 60 sccm, Oo800 sc cm) deposition of 200 nm, the decomposition of the gas by the detector there between removal device outlet confirmed. The removal device was heated to 90 ^eC . Even after repeated 30 times the film formation, S i H _4. PH ₃ is not detected at all, the removal device of the present real施例has been found to be practical.

In this example, a 4 mm diameter, 60 cm tube was used.However, the hole diameter and length of the honeycomb may be appropriately determined depending on the pressure and flow rate of the hydride gas used, but the hole diameter is usually several mm. It is preferably used.

(Example 2)

FIG. 8 shows a second embodiment of the present invention.

In this embodiment, distribution of N i F ₂ tube and N i pipe into a different container 83, 83 ', respectively, and heated to 85 ° C, 1 30 ° C, respectively, BSG (5% S i ( N 2 dilution)

800 sc cm, 5% B. H c (N ₂ _{dilution) 1 60 sccm, 0 0 800} sc cm) 3 0 0 nm of the film formation and the n ⁺ polysilicon Con (5% S i 1 s 1 m, 0. 5% A s H 3 2 s 1 m. Ar I O slm) A film was formed to a thickness of 400 nm. Even after this film formation was repeated 30 times, Si H ^, AsH ₃ , and BgHe were not detected at all.

(Example 3)

FIG. 9 shows a third embodiment of the present invention.

This embodiment is an example in which a removing device is provided on the downstream side of the exhaust system similarly to the conventional exhaust gas treatment device.

In FIG. 9, 91 is a special gas inlet, 92 and 92 'are packed columns filled with a carrier coated with a fluorine nickel film and a Ni film, 93 is a heater, 94 is a gas detector,

95 is a washing tower, 96 is a water circulation tank, and 97 is a water circulation pump.

In the removing apparatus of the present embodiment, two packed towers are arranged in parallel, and only one of them is used. Attach a gas detector to the gas outlet of the packed tower to monitor the status of the removal equipment during operation. When the capacity of the packed tower is lost, switch to the other packed tower. The discharged gas may be sent to a scrubber for gas discharged from other semiconductor manufacturing equipment.

Industrial applicability

According to the present invention, the mixed gas of the hydride gas can be effectively removed, and furthermore, since the gas can be installed on the upstream side of the exhaust pump, maintenance of the exhaust system and the like is remarkably facilitated. The operation rate can be greatly improved. In addition, since no powder solids are generated, clogging does not occur in pumps, packed towers and other devices, and the removal can be performed extremely stably.

Claims

The scope of the claims

1. A hydride gas removal method comprising removing a hydride gas by bringing a mixed gas containing at least two or more hydride gases into contact with nickel fluoride and nickel to decompose and / or adsorb the mixed gas. Removal method.

2. The method for removing a hydride gas according to claim 1, wherein the hydride gas is a hydride gas of an element of Group II, IV or V of the periodic table.

3. The method for removing a hydride gas according to claim 1, wherein the hydride gas is decomposed and removed by heating the nickel fluoride and the nickel.

4. The method for removing a hydride gas according to claim 3, wherein the nickel fluoride and the nickel gel are heated to different temperatures.

5. A hydride gas of a group III element or a group V element of the periodic table is contacted with nickel to decompose and / or adsorb the hydride gas, thereby removing the hydride gas. Removal method.

6. The method for removing a hydride gas according to claim 5, wherein the hydride gas is decomposed and removed by heating the nickel.

7. At least one container having an inlet and an outlet for a mixed gas containing at least two or more hydride gases, wherein nickel fluoride and nickel are placed in the container so as to contact the mixed gas. A hydride gas removing device which is arranged individually or together, and provided with a heating means for heating the nickel fluoride and the nigel. '

8. The hydride gas removing device according to claim 7, wherein the heating means heats the nickel fluoride and the nickel gel to different temperatures.

9. Place nickel in a container having an inlet and an outlet for a hydride gas of a group III element or a group V element of the periodic table so as to contact the gas, and heat the nickel. A hydride gas removing device provided with a heating means.