JP3340513B2 - Hazardous gas purification method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying harmful gases, and more particularly, to an MOCV in a semiconductor manufacturing process.
The present invention relates to a method for purifying various alkyl hydrogen compound-based harmful gases used in D (metal organic chemical vapor deposition) and other CVD processes.

In recent years, with the development of the semiconductor industry, high integration and miniaturization have progressed, and tert-butylarsine, tert-butylphosphine, tert-butylthiol, iso-
The use of alkyl hydrogen compound-based gases such as propylarsine and iso-propylphosphine has been increasing and has become indispensable as a raw material gas, a doping gas, or a gas for forming a metal thin film in a CVD process.
Many of these alkyl hydrogen compounds are highly toxic or unknown, and most of them are flammable. There is a need.

[0003]

2. Description of the Related Art As a method of removing harmful gases, a wet method of absorbing and decomposing by a scrubber and a dry method of using activated carbon or a porous adsorbent of an inorganic compound are known. Regarding the method, there is a problem that the alkyl hydrogen compound is not water-soluble in the wet method, so there is no effective absorbing solution, and the dry method is desorbed because the adsorbent such as activated carbon is physically adsorbed.

[0004]

As described above, in the prior art, there is no method for efficiently removing these alkyl hydrogen compounds, and the appearance of an excellent removal method has been desired.

[0005]

Means for Solving the Problems The present inventors have studied these V
After extensive studies on the removal of alkyl hydrogen compounds (hereinafter referred to as alkyl hydrogen compounds) of group b or group VIb elements, copper (II) oxide and manganese oxide (I
It has been found that these alkyl hydrogen compounds can be efficiently and safely removed by using a purifying agent obtained by impregnating a metal oxide containing V) as a main component with an alkali component, thereby completing the present invention. That is, the present invention relates to a method in which a gas containing at least one alkyl hydrogen compound of a Vb group or VIb element, which is a harmful component, is converted into a metal oxide containing copper (II) oxide and manganese (IV) oxide as a main component by an alkali metal. A method for purifying harmful gas, comprising contacting a compound with a purifying agent to which a compound is impregnated to remove harmful components from the gas.

The purification method of the present invention is contained in a gas such as air, nitrogen and hydrogen, and has a general chemical formula of Rm-M-Hn.
[R is an alkyl group, M is a Vb group or VIb group element, m
And n is a positive integer]. As the alkyl hydrogen compound Vb group element, arsenic, phosphorus, those containing antimony, for example, tert- butyl arsine (t-C ₄ H ₉ As
H ₂ ), tert-butylphosphine (tC ₄ H ₉ P
H _2), isopropyl arsine (i-C ₃ H ₇ As
H ₂ ), isopropylphosphine (i-C ₃ H ₇ P)
H _2), etc., The alkyl hydrogen compound VIb group element, sulfur, selenium, is intended to include tellurium, for example, tert- butyl thiol (t-C ₄ H ₉ S
H), tert-butyl selenol (tC ₄ H ₉ Se
H), tert-butyl tellurol (tC ₄ H ₉ Te)
H), isopropyl thiol _{(i-C 3 H 7 SH} 2),
Examples thereof include isopropyl selenol (i-C ₃ H ₇ SeH ₂ ) and isopropyl tellurol (i-C ₃ H ₇ TeH ₂ ). The purification method of the present invention can remove a large amount of harmful gas quickly and usually at normal temperature. Excellent effects such as rapid purification of air contaminated by gas can be obtained.

In the present invention, a purifying agent in which an alkali metal compound is impregnated with a metal oxide is used. The metal oxide mainly contains copper (II) oxide and manganese (IV) oxide, and other oxides include cobalt (III) oxide, silver (I) oxide and silver (II) oxide. ) May be mixed. The content of copper (II) oxide and manganese (IV) oxide in the metal oxide is usually 60 wt.
%, Preferably 70% by weight or more. The ratio of manganese (IV) oxide to copper (II) oxide is usually 1: 0.8 to 5.0, preferably 1: 1.2 to 5.0.
It is about 3.0. These metal oxide-based compositions are:
Although it can be prepared by mixing various components or by various known methods, it is convenient to use them as it is commercially available as hopcalite. Hopcalite is composed of 40% by weight of copper (II) oxide and 60% by weight of manganese (IV) oxide
Some are commercially available centering on the two-element system, and the other are a mixture of a copper-manganese system with an oxide such as aluminum or silicon at a ratio of 30% by weight or less. And silver oxide.

These metal oxides are usually used by molding, and various shapes such as crushed products, extruded products, and tableted products can be used. The size is about 4 to 20 mesh for crushed products, 1.5 to 4 mm in diameter and 3 to 20 mm in length for extruded products, and usually 3 to 20 mm in diameter for tableted products. 6m
m and a height of about 3 to 6 mm are preferable.

In the present invention, the alkali metal compound to be impregnated with the metal oxide includes hydroxides, oxides and carbonates of potassium, sodium and lithium.
Examples include potassium hydroxide, sodium hydroxide, lithium hydroxide, potassium oxide, sodium oxide, potassium carbonate, sodium carbonate, and mixtures thereof. Among them, potassium hydroxide, sodium hydroxide, potassium oxide and potassium carbonate are preferred. The amount of the alkali metal compound impregnated in the metal oxide varies depending on the type and concentration of the alkyl hydrogen compound gas and cannot be specified unconditionally. It is 1 to 50 parts by weight, preferably about 3 to 15 parts by weight in conversion. If the amount is less than 1 part by weight, the efficiency of removing the alkyl hydrogen compound is reduced. On the other hand, if it exceeds 50 parts by weight, the metal oxide is not sufficiently retained and becomes expensive.

The concentration of the harmful gas applied to the present invention is usually 1% or less, preferably 0.1% or less. Also,
The contact temperature between the purifying agent and the gas is about 0 to 100 ° C,
It is usually operated at room temperature (10 to 50 ° C.) and does not require any particular heating or cooling. However, after the start of contact, if the concentration of the harmful gas is high or if a highly reducing gas such as hydrogen is contained due to the reaction heat, the heat is generated by 10%.
Although a temperature rise of about -40 ° C. may be observed, no abnormal heat generation occurs. The pressure at the time of contact is usually normal pressure, but it is also possible to operate under reduced pressure or a pressurized pressure such as 1 kg / cm ² G. Gases such as air, nitrogen, and hydrogen to which the present invention is applied may be in a dry or wet state as long as no condensation occurs.
Generally, it is often used at a relative humidity of 30 to 100% corresponding to ordinary air. In such a case, a purifying agent having a free water content of about 5 to 30 wt% is suitable.

The concentration and flow rate of the alkyl hydrogen compound-based gas contained in the gas to be treated to which the purification method of the present invention is applied are not particularly limited, but it is generally desirable that the higher the concentration, the lower the flow rate. The concentration of the harmful gas that can be removed is usually 1% or less, but when the flow rate is small, a higher concentration of an alkyl hydride gas can be treated. The purifying cylinder is designed according to the concentration of the harmful gas, the amount of the gas to be treated, and the like. When the concentration of the harmful gas is relatively low such as 0.1% or less, the linear velocity (LV) of the cylinder is 0.5 to 5
It is preferable to design the LV in the range of 0.05 to 20 cm / sec when the harmful gas concentration is about 0 to 1% at 0 cm / sec and 10 cm / sec or less when the concentration is as high as 1% or more. Therefore, in the case of high concentration harmful gas discharged constantly from the semiconductor manufacturing process, the harmful gas leaks rapidly from the gas cylinder at 10 cm / sec or less and is diluted with a large amount of air. For example, the standard value of LV is 0.5 to 50 cm / sec.

The purifying agent is usually filled in a purifying column for harmful gas and used as a fixed bed, but can also be used as a moving bed or a fluidized bed. Usually, the purifying agent is filled in the purifying column, and the gas containing the alkyl hydrogen compound gas is flowed into the purifying column, and the harmful component alkyl hydrogen compound is removed by bringing the gas into contact with the purifying agent. In the present invention, when the purifying agent is filled in the purifying column, the packing density is 1.
It is about 0 to 1.5 g / ml.

[0013]

【Example】

Example 1 to 8 (Mn-Cu composition) manganese dioxide (MnO ₂₎ 50
wt%, copper oxide (CuO) 22 wt%, magnesium oxide (MgO) 12.5 wt%, aluminum oxide (Al
₂ O ₃ ) 12.5 wt%, 1.5 mm in diameter, ₃ to 1 in length
A commercially available hopcalite, which is a 0 mm extruded product, was used. (Preparation of remover) A concentration of 5 was added to 1000 g of this hopcalite.
After spraying and impregnating a 0 wt% potassium hydroxide solution,
By drying at 120 ° C. for 2 hours, potassium hydroxide is 2 to 40% by weight based on 100 parts by weight of hopcalite.
The four types of purifying agents impregnated in the range were prepared.

(Removal test)
Then, 28 ml of the effluent was filled in a 28-mm purifying cylinder, and a test for removing tert-butylarsine and tert-butylphosphine was performed. Each alkyl hydride diluted to a concentration of 0.1 vol% with nitrogen is allowed to flow at a flow rate of 0.85 L / min (vacuum linear velocity 5 cm / sec) at room temperature of 20 ° C., and the alkyl hydrogen compound is contained in the outlet gas of the filling cylinder. The time until detection started (effective processing time) was measured. For detection, a detection agent (lower detection limit: 10 ppm) in which nickel chloride was supported on silica gel as a color-change component was used. Table 1 shows the measurement results.

[0015]

Table 1 Example Hazardous Gas KOH Hazardous Gas Cylinder Effective Treatment Type Content Concentration Linear Velocity Time wt% vol% cm / sec min 1 t-BuAsH ₂ 2 0.15 615 2〃5〃 ６０ 603 3 ２０ 20 〃 〃 705 4 40 〃 ６８ 683 5 t-BuPH ₂ 2 〃 ４５０ 450 6 ５ 5 〃 ４ 495 7 〃 20 〃 ５ 5138 〃 40 〃 ４８ 487

Comparative Examples 1 and 2 Yashigara activated carbon (manufactured by Takeda Pharmaceutical Co., Ltd.)
8-24 mesh) and Molecular Sieve 5A (8-24 mesh, manufactured by Union Showa Co., Ltd.). (Removal test) 28 ml of the remover was filled in a remover cylinder having an inner diameter of 19 ml, heated and regenerated at 200 ° C. while flowing nitrogen, cooled to room temperature, and then tested for removal of tert-butylarsine and tert-butylphosphine. Was done. Table 2 shows the results.

[0017]

Table 2 Comparative Example Hazardous Gas Purifier Hazardous Gas Cylinder Effective Treatment Type Concentration Type Linear Velocity Time Vol% cm / sec min 1 t-BuAsH ₂ Activated Carbon 0.1 567 ₂ t-BuPH ₂ MS5A ３４ ３４ 34

Examples 9 to 13 (Mn-Cu composition) The same commercially available hopcalite as used in Example 2 was used. (Adjustment of removing agent) The same kind of purifying agent as used in Example 2 was used.

(Removal test)
A 9 mm removal cylinder was filled with 28 ml, and a removal test of tert-butylthiol, tert-butylselenol, tert-butyltellurol, iso-propylarsine or iso-propylphosphine as an alkyl hydrogen compound was performed. Each alkyl hydrogen compound diluted to a concentration of 0.1 vol% with nitrogen was supplied at a flow rate of 0.85 L / min.
(Vacuum linear velocity: 5 cm / sec), flow was performed at room temperature of 20 ° C., and a time (effective treatment time) until alkyl hydride was started to be detected in the outlet gas of the filling cylinder was measured. tert-butylthiol, tert-butylselenol and te
For the detection of rt-butyl tellurol, a detecting agent in which chloroauric acid and a copper salt are supported on silica gel as discoloring components (lower detection limit: 10 ppm), iso-propylarsine, iso
For the detection of -propylphosphine, the above-mentioned detecting agent containing nickel chloride as a color changing component (lower detection limit: 10 ppm) was used. Table 3 shows the above results.

[0020]

Table 3 Example KOH of harmful gas Hazardous gas vacant cylinder Effective treatment type Content concentration Linear velocity wt% vol% cm / sec min 9 t-BuSH 5 0.15 922 10 t-BuSeH 5 0.1 5 1380 11 t-BuTeH 5 0.1 5 1250 12 i-PrAsH ₂ 5 0.15 652 13 i-PrPH ₂ 5 0.15 588

Examples 14 to 21 (Preparation of remover) Four kinds of resins having different amounts of sodium hydroxide to be applied in the same manner as in Examples 1 to 8 except that sodium hydroxide was used instead of potassium hydroxide. Was prepared. (Removal test) These removers were prepared in the same manner as in Examples 1 to 8 by using tert-butylarsine and tert-butylarsine.
A butyl phosphine removal test was performed. Table 4 shows the results.

Table 4 Example NaOH of harmful gas Hazardous gas empty cylinder Effective treatment type Concentration of content Linear velocity Processing time wt% vol% cm / sec min 14 t-BuAsH ₂ 2 0.15 588 15 ５50. 1 ６０ 605 16 ０．１ 20 0.1 〃 611 17 40 0.1 ５ 537 18 t-BuPH ₂ 2 0.1 ４５ 455 19 〃 50.1 498 20 ２０ 20 0.1 〃 504 21 ４０ 400 0 .1 $ 469

Examples 22 to 29 (Mn-Cu composition) The composition of the metal oxide was manganese dioxide (MnO ₂ ) 50.
wt%, copper oxide (CuO) 30 wt%, cobalt oxide (Co ₂ O ₃ ) 15 wt%, silver oxide (Ag ₂ O) 5 wt
%, A commercially available catalyst which was an extruded product having a diameter of 1.5 mm and a length of 3 to 10 mm was used. (Preparation of the remover) A potassium hydroxide solution having a concentration of 50 wt% was sprayed and impregnated on 1000 g of the catalyst, and then dried at 120 ° C for 2 hours, whereby 2 to 40 wt% of potassium hydroxide was added to 100 parts by weight of the catalyst. % Of the four types of purifying agents were prepared.

(Removal test)
The effective treatment time was measured in the same manner as in Examples 1 to 8 by filling 28 ml into a purification column having a diameter of 28 mm. Table 5 shows the results.

[0025]

Table 5 Example 5 Hazardous gas KOH Hazardous gas cylinder Effective treatment type Content concentration Linear velocity Processing time wt% vol% cm / sec min 22 t-BuAsH ₂ 2 0.15 676 23 {5} 〃 721 24 〃 20 undefined undefined 732 25 〃 40 undefined undefined 718 26 t-BuPH _{2 2} undefined undefined 493 27 〃 5 undefined undefined 530 28 〃 20 undefined undefined 556 29 〃 40 undefined undefined 514

[0026]

According to the method for removing harmful gas of the present invention,
Efficient and extremely rapid removal of alkyl hydride-based gases, such as tert-butylarsine and tert-butylphosphine, which have been difficult to remove, such as tert-butylarsine and tert-butylphosphine. Therefore, an excellent effect can be obtained for purifying harmful gases in semiconductor manufacturing equipment and the like.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B01D 53/34

Claims (10)

(57) [Claims] 1. A gas containing at least one alkyl hydride of a Vb group or VIb element, which is a harmful component,
Removing a harmful component from the gas by contacting a metal oxide containing copper (II) oxide and manganese (IV) oxide as a main component with a purifying agent obtained by impregnating an alkali metal compound with the metal oxide; Purification method. 2. The Vb group element is arsenic or phosphorus.
Purification method according to 1. 3. The method according to claim 1, wherein the Group VIb element is sulfur, selenium or tellurium. 4. An alkyl hydrogen compound wherein the alkyl group is ter
A t-butyl group or an iso-propyl group.
Purification method according to 1. 5. The method according to claim 1, wherein the alkali metal compound is a hydroxide, oxide or carbonate of potassium, sodium or lithium. 6. The alkali metal compound is potassium hydroxide,
The purification method according to claim 3, wherein the purification method is sodium hydroxide, potassium oxide, or potassium carbonate. 7. The purification method according to claim 1, wherein the amount of the alkali metal compound impregnated is 1 to 50 parts by weight in terms of hydroxide of each alkali metal per 100 parts by weight of the metal oxide. 8. The content of copper (II) oxide and manganese (IV) oxide in the metal oxide is at least 60 wt%, and the ratio of manganese (IV) oxide to copper (II) oxide is 1: 1: The purification method according to claim 1, wherein the ratio is 0.8 to 5.0. 9. Copper (II) oxide and manganese oxide (I)
The purification method according to claim 6, wherein the metal oxide other than V) includes at least one of cobalt oxide and silver oxide. 10. The purification method according to claim 1, wherein the contact temperature between the purifying agent and the gas is 100 ° C. or lower.