CN1195573C - Reactant and method for decomposition of fluorine compounds, and use thereof - Google Patents

Abstract

A reactive agent for decomposing fluorine compounds comprising alumina and an alkaline earth metal compound, a process for decomposing fluorine compounds, comprising contacting the reactive agent with a fluorine compound at a temperature of 200 DEG C. or more, and a process for manufacturing a semiconductor device, comprising an etching or cleaning and a decomposing using the reactive agent.

Description

Be used for the reactant of decomposing fluorine compounds and method and uses thereof

The present invention relates to be used to make for example following various fluorine compounds to decompose and the reactant and the method for detoxifcation, cfc (being designated hereinafter simply as " CFC ") for example, hydrogen cfc (being designated hereinafter simply as " HCFC "), perfluocarbon (being designated hereinafter simply as " PFC "), hydrofluorocarbons (being designated hereinafter simply as " HFC "), perfluorinated ethers (being designated hereinafter simply as " PFE "), hydrofluorination ether (being designated hereinafter simply as " HFE ") and sulphur fluoride, be included in the compound that is produced when using these fluorine compounds simultaneously, for example the HF that in the etching of making the semiconductor devices process or cleaning step, is produced, SiF ₄Or COF ₂

Most of above-mentioned fluorine compounds generally are stable, and harmless, and therefore, their use extends to different field.Recent years, be used for etching as the HFC of refrigerant such as air conditioning for automobiles with in making semiconductor processes or greatly increase as the quantity of the PFC of purge gas.And because of its fabulous electrical insulation property, a large amount of sulfur hexafluorides are used in capacitor, the transformer etc.These fluorine compounds are stable, thereby are important latencies of global warming.If a kind of like this fluorine compounds former state is discharged in the global environment, its influence continues stage long period, and this is frightening.SF particularly ₆, CF ₄, C ₂F ₆Deng being very stable gas, in air, has the very long life-span.Therefore, use the back when discharging, these gases must be released after being decomposed into the innocuous substance that global environment is not had influence again.As their alternative compounds, people have proposed PFE and HFE, but these also have same global warming issue.And, in making the semiconductor devices process, use the gas of back discharging to contain HF, SiF ₄And COF ₂Deng gas, these gases are released after also must being decomposed into safe material jointly with above-claimed cpd again.

As refrigerant, washing agent etc. and a large amount of CFC that uses and can not former state discharge as the HCFC of its alternative compounds must be decomposed into harmless material,, cause serious environmental problem so far because they damage the ozone layer.

Traditionally, the technology of these class fluorine compounds of known decomposition is (1) decomposition by combustion for example, with compound with fuel treatment (seeing WO 94/05399), (2) thermal decomposition method, use a kind of reactant, for example silica or zeolite (seeing JP-A-7-116466 (term used herein " JP-A " is meant " uncensored and disclosed Japanese patent application ")) and (3) catalytic decomposition method are used (seeing JP-A-10-286434) such as alumina.

But, the disadvantage of method (1) is must control NO in combustion process _xGeneration, the perhaps essential Macrodilution gas that uses causes decomposing than descending, and, must contained HF handle again in the waste gas of back to decomposing.Method (2) also has a problem, is in particular to make decomposed P FC (CF for example ₄, C ₂F ₆) speed enough high, need 1000 ℃ or above high temperature, and, also must be to decomposing the SiF that is contained in the waste gas of back ₄Carry out independent processing again Deng compound.According to method (3), decomposition can be carried out under the low temperature of comparing with method (1) and (2), but, still has following point.Concerning decomposing 100% PFC, must be with dilution supply gas such as air, to reduce the PFC concentration in the gas.And, in order to reach the catalytic action of alumina, thereby fluoride of accumulating on a large amount of steam hydrolysis alumina surface etc. must be arranged simultaneously.Therefore, must corrosion-resistant material and the HF of HF be handled again, HF is that the pyrogenetic decomposition by the lip-deep fluoride of alumina is generated.

Using industrial favourable process, the method for effective decomposing fluorine compounds itself is unknown so far, and needs more the improvement.

One object of the present invention is to address the above problem, and a kind of reactant is provided, and it can be with relatively low temperature thermal decomposition fluorine compounds, and need not to add entry, can be with the catabolite of fluorine compounds (for example F, SO _x) be fixed on the reactant.

Another object of the present invention provides the method for particularly decomposing the PFC that is difficult to decompose effectively.

The inventor has carried out broad research for addressing the above problem, and found that, a kind of reactant of decomposing fluorine compounds has reached these purposes, and it comprises alumina and a kind of alkaline earth metal compound.And, the inventor also finds, in the method for decomposing fluorine compounds, this method comprises contacts fluorine compounds and above-mentioned reactant under 200 ℃ or above temperature, these fluorine compounds can be thermal decomposited, chlorine atom, fluorine atom and/or the sulphur atom that is generated can be fixed on the reactant with the form of chloride, fluoride and/or the sulfate of alkaline-earth metal, if necessary, in reactant, add a kind of metal oxide in fluorine compounds, to introduce oxygen, the carbon monoxide that is generated can be simultaneously oxidized, thereby detoxified.Based on these discoveries, finished the present invention.The present invention relates to be used for the reactant and the method for decomposing fluorine compounds, following (1) is described to (24):

(1) is used for the reactant of decomposing fluorine compounds, comprise alumina, alkaline earth metal compound and metal oxide, described alkaline earth metal compound is the carbonate of magnesium, calcium, strontium or barium, described alumina and alkaline earth metal compound have 1: 9 to 1: 1 mass ratio, described metal oxide is to be selected from least a in the oxide of copper, tin, nickel, cobalt, chromium, molybdenum, tungsten and vanadium, the content of described metal oxide is represented with its ratio to the gross mass of described alumina and alkaline earth metal compound, is 1: 99 to 5: 95.

(2) as above (1) described reactant that is used for decomposing fluorine compounds, the specific area of wherein said alumina is 50m ²/ g or more than.

(3) as above (1) or (2) any described reactant that is used for decomposing fluorine compounds, wherein said alumina is the pseudobochmite alumina.

(4) as above (1) or (2) any described reactant that is used for decomposing fluorine compounds, wherein said alumina is to obtain by cure the pseudobochmite alumina under 400 to 1000 ℃ stoving temperature.

(5) as above (1) or (2) any described reactant that is used for decomposing fluorine compounds, wherein this alumina and alkaline earth metal compound are present in the described reactant with form of powder separately, and particle diameter is 100 μ m or following.

(6) as above (1) or (2) any described reactant that is used for decomposing fluorine compounds contains 0.1 quality % or following a kind of alkali metal.

(7) as above (1) or (2) any described reactant that is used for decomposing fluorine compounds, it is by cure the granular disintegration that obtains under 400 to 700 ℃ temperature.

(8) as above (7) described reactant that is used for decomposing fluorine compounds, it is that particle diameter is 0.5 to 10mm granular disintegration.

(9) as above (1) or (2) any described reactant that is used for decomposing fluorine compounds contains 1 quality % or following water.

(10) as above (1) or (2) any described reactant that is used for decomposing fluorine compounds, wherein said fluorine compounds are at least a fluorine compounds that are selected from down group: perfluocarbon, hydrofluorocarbons, cfc, hydrogen cfc, perfluorinated ethers, hydrofluorination ether, fluorinated olefins, sulphur fluoride, SiF ₄And COF ₂

(11) as above (10) described reactant that is used for decomposing fluorine compounds, wherein said fluorine compounds contain hydrogen chloride, hydrogen fluoride or hydrogen chloride and hydrofluoric mixture.

(12) be used for the method for decomposing fluorine compounds, comprise a kind of reactant and fluorine compounds are contacted under 200 ℃ or above temperature, wherein said reactant comprises alumina and a kind of alkaline earth metal compound, this alkaline earth metal compound is a magnesium, calcium, the carbonate of strontium or barium, and comprise and be selected from copper, tin, nickel, cobalt, chromium, molybdenum, at least a oxide in the oxide of tungsten and vanadium, described alumina and alkaline earth metal compound have 1: 9 to 1: 1 mass ratio, the content of described metal oxide is represented with its ratio to the gross mass of described alumina and alkaline earth metal compound, is 1: 99 to 5: 95.

(13) as above (12) described method that is used for decomposing fluorine compounds, wherein the concentration of these fluorine compounds in the gas processed by contacting with this reactant is 0.01 to 10 volume %.

(14) be used for the method for decomposing fluorine compounds, comprise and make a kind of reactant and fluorine compounds under 500 ℃ or above temperature, in the presence of oxygen, contact, thereby the generation of control carbon monoxide, wherein said reactant comprises alumina and a kind of alkaline earth metal compound, this alkaline earth metal compound is a magnesium, calcium, the carbonate of strontium or barium, and comprise and be selected from copper, tin, nickel, cobalt, chromium, molybdenum, at least a oxide in the oxide of tungsten and vanadium, described alumina and alkaline earth metal compound have 1: 9 to 1: 1 mass ratio, the content of described metal oxide is represented with its ratio to the gross mass of described alumina and alkaline earth metal compound, is 1: 99 to 5: 95.

(15) as above (14) described method that is used for decomposing fluorine compounds, wherein the concentration of this oxygen in pending gas is 20 volume % or following.

(16) as above (12) or (14) any described method that is used for decomposing fluorine compounds, wherein this reactant is fixedly become alkaline earth metal chloride, alkali earth metal fluoride and/or alkali earth metal sulfate respectively with chlorine atom, fluorine atom and/or the sulphur atom that fluorine compounds produce through contacting.

(17) method that is used for producing the semiconductor devices, comprise and use etching or the cleaning step of at least a fluorine compounds as etching gas or purge gas, these fluorine compounds are selected from by perfluocarbon, hydrofluorocarbons, cfc, the hydrogen cfc, perfluorinated ethers, hydrofluorination ether, the group that fluorinated olefins and sulphur fluoride are formed, also comprise and use the reactant that comprises alumina and a kind of alkaline earth metal compound to decompose from the decomposition step of the gas that contains these fluorine compounds of described etching or cleaning step discharging, this alkaline earth metal compound is a magnesium, calcium, the carbonate of strontium or barium, and described reactant also comprises and is selected from copper, tin, nickel, cobalt, chromium, molybdenum, at least a oxide in the oxide of tungsten and vanadium, described alumina and alkaline earth metal compound have 1: 9 to 1: 1 mass ratio, the content of described metal oxide is represented with its ratio to the gross mass of described alumina and alkaline earth metal compound, is 1: 99 to 5: 95.

(18) as above (17) described method that is used for producing the semiconductor devices, wherein the gas from described etching or cleaning step discharging is the gas that contains at least a fluorine compounds, and these fluorine compounds are selected from by perfluocarbon, hydrofluorocarbons, cfc, hydrogen cfc, perfluorinated ethers, hydrofluorination ether, fluorinated olefins, sulphur fluoride, SiF ₄And COF ₂The group of forming.

(19) as above (18) described method that is used for producing the semiconductor devices, the wherein said gas that contains fluorine compounds contains hydrogen chloride, hydrogen fluoride or hydrogen chloride and hydrofluoric mixture.

(20) as above (17) described method that is used for producing the semiconductor devices, wherein in described decomposition step, the fluorine compounds in the pending gas are to decompose under 200 ℃ or above temperature.

(21) as above (17) described method that is used for producing the semiconductor devices, wherein in described decomposition step, the fluorine compounds concentration in the pending gas is 0.01 to 10 volume %.

(22) as above (17) described method that is used for producing the semiconductor devices, wherein this decomposition step is under 500 ℃ or above temperature, carries out in the presence of oxygen, thus the generation of control carbon monoxide.

(23) as above (22) described method that is used for producing the semiconductor devices, wherein in described decomposition step, the oxygen concentration in the pending gas is 20 volume % or following.

(24) as above (17) described method that is used for producing the semiconductor devices is wherein fixedly become alkaline earth metal chloride, alkali earth metal fluoride and/or alkali earth metal sulfate respectively at the chlorine atom, fluorine atom and/or the sulphur atom that use this reactant to decompose to be produced in the decomposition step of the gas that discharges from described etching or cleaning step.

In a word, the invention provides " reactant that is used for decomposing fluorine compounds that comprises alumina and a kind of alkaline earth metal compound; this reactant can make and be easy to damage the ozone layer or decomposition of the fluorine compounds of global warming latency and detoxifcation ", " method that is used for decomposing fluorine compounds; comprise fluorine compounds and above-mentioned reactant are contacted under 200 ℃ or above temperature ", " method that is used for decomposing fluorine compounds; comprise and in fluorine compounds, introduce oxygen; these fluorine compounds and above-mentioned reactant are contacted under 500 ℃ or above temperature; thus the generation of control carbon monoxide ", " method that is used for producing the semiconductor devices; comprise etching or cleaning step and decomposition step, the latter uses above-mentioned reactant to decompose the gas that contains fluorine compounds that discharges from etching or cleaning step ".

According to above-mentioned common process, promptly a kind of thermal decomposition method of reactant and the decomposition method that (3) use a kind of alumina catalyst are used in (1) decomposition by combustion, (2), and the catabolite of fluorine compounds is the materials that still environment had adverse effect.Therefore, must handle separately in the decomposition step later stage and make catabolite detoxifcation.This makes the miniaturization of device become a difficult problem.The gas that discharges from the manufacture process of semiconductor devices particularly for example is used for the PFC waste gas of etching or cleaning, also contains fluorine compounds except PFC, for example HF, SiF ₄And COF ₂Therefore, for the catalytic decomposition method, in early days also must be to SiF ₄Deng the processing of detoxifying, this needs complicated and heavy device.And concerning the decomposition of the PFC that is difficult to especially decompose, high temperature is necessary, but this can cause a problem, even build the material degradation of reactor.

On the other hand, according to the present invention, the fluorine compounds that are used for the electric insulation purpose can effectively be decomposed at low temperatures as refrigerant or in the process of making semiconductor devices.Among the present invention, fluorine compounds are with when using these fluorine compounds, for example the SiF that is generated when etching ₄Deng being decomposed simultaneously.And, meanwhile carrying out reaction fixing and then detoxifcation, for example be fixed to alkali earth metal fluoride (CaF for example by the fluorine that decomposition generated ₂).Therefore, also can solve the problem of this respect.

Fig. 1 is the system schematic of device layout, an example of equipment therefor in expression the present invention practice.

The fluorine compounds that can be decomposed by reactant of the present invention are described. The example of CFC comprises such as CClF₃、 CCl ₂F ₂、CCl ₃F、C ₂Cl ₃F ₃、C ₂Cl ₂F ₄And C₂ClF ₅Deng compound. The example of HCFC comprises such as CHClF₂And C₂HCl ₂F ₃Deng compound. The example of PFC comprises CF₄、C ₂F ₆、C ₃F ₈And C₄F ₈(octafluorocyclobutane). The example of HFC comprises such as CH₃F、CH ₂F ₂、CHF ₃And C₂H ₂F ₄Deng compound. The example of PFE comprises such as CF₃OCF ₃And CF₃OCF ₂CF ₃Deng compound. The example of HFE comprises such as CHF₂OCHF ₂、 CHF ₂OCH ₂CF ₃And CH₃OCF ₂CF ₃Deng compound. The example of sulphur fluoride comprises such as SF₆And S₂F ₁₀Deng compound. Reactant of the present invention also can be used for the compound except these fluorine compounds. For example, can make similarly following substance decomposition and detoxifcation, such as CF₃OCF＝CF ₂Deng unsaturated compound and C₅F ₈(Octafluorocyclopentane), or in etch step, use the compound that exists in the waste gas that discharges behind the PFC, such as HF, SiF₄And COF₂。

These fluorine compounds can be used a kind of inert gas dilution, for example helium, argon or nitrogen, or use Dilution air, and perhaps can be mist a kind of and inert gas or air, contain 0.01 volume % or above fluorine compounds steam (being at normal temperatures liquid). Fluorine compounds can be single compound or the mixture of two or more compounds.

The reactant that the present invention is used for decomposing fluorine compounds is described below.

The reactant that the present invention is used for decomposing fluorine compounds is characterised in that it contains a kind of alumina and a kind of alkaline earth metal compound. Alumina in the reactant is a kind of typical acidic materials (solid acid), known separately decomposing fluorine compounds. For example " catalyst " 34 volumes, 7 phase 464-469 pages or leaves (1992) have been described alumina as the purposes of catalyst in decomposing CFC. Briefly, when using alumina (Al₂O ₃) when decomposing CFC, the fluorine that generates when the alumina surface is decomposed is fluoridized. So, AlF₃Alumina is poisoned, thereby make it lose at short notice catalytic activity. But, metal halide generally at high temperature is easy to be hydrolyzed, and utilizes this character, when carry out AlF in the presence of steam₃Hydrolysis the time ( ), the alumina of regenerating can use in catalysis. But, this reaction in the presence of water has a problem, AlF₃Decompose generation hydrogen fluoride, device is had corrosiveness. In order to address this problem, the inventor for can not have water in the presence of and continuous decomposition fluorine compounds under the low temperature, the distintegrant that particularly is difficult to the PFC that decomposes carried out various researchs. Found that, use comprises the reactant of alumina and a kind of alkaline earth metal compound, and fluorine compounds can decompose under 200 ℃ or above reaction temperature, and the hydrogen fluoride that generates can be fixed to alkali earth metal fluoride, thereby reach detoxication, and can not cause the corrosion to device.

According to the difference of fluorine compounds kind, the present invention is used for reactant decomposing fluorine compounds, that comprise alumina and a kind of alkaline earth metal compound can generate carbon monoxide, as follows:

(1)

(2)

Carbon monoxide can be oxidized under the capacity partial pressure of oxygen. But, in the limited situation of partial pressure of oxygen, have been found that this metal is selected from by copper, tin, nickel, cobalt, chromium, molybdenum, tungsten and vanadium, even carbon monoxide also can be oxidized to carbon dioxide under low oxygen partial pressure by add the oxide of at least a metal in reactant. This metal oxide is considered to also play a kind of effect of co-catalyst, can disconnect the carbon-carbon bond of fluorine compounds.

The used alumina of the present invention is not particularly limited, and but, is hole (size in hole and volume) but the alumina of importantly selecting should have the active site of enough a large amount of decomposing fluorine compounds with enough specific areas of large adsorbable fluorine compounds. Therefore, alumina preferably has 50m²/ g or above specific area, more preferably 100 to 300m²/ g. And, the important low suitable raw material of impurity concentration of still selecting. Example that can alumina raw used in this invention comprises activated bauxite and pseudobochmite alumina. Pseudobochmite alumina preferably wherein. After can mixing with a kind of alkaline earth metal compound, uses in pseudobochmite alumina itself. In the situation of curing the pseudobochmite alumina, be in such as the inert gases such as nitrogen or air, to carry out a few hours if cure, temperature is 400 to 1000 ℃, is preferably 500 to 800 ℃, more preferably 500 to 600 ℃ that it is sufficient curing so.

The alkali metal content that exists as impurity in the alumina is preferably 0.1 quality % or following, is preferably 0.01 quality % or following, more preferably 0.001 quality % or following. And the particle diameter of alumina is 100 μ m or following, is preferably 30 μ m or following, the alumina of more preferably 5 μ m or following, and use powder morphology.

Alkaline earth metal compound as the another kind of component of reactant is described below.

Alkaline earth metal compound is preferably the carbonate of magnesium, calcium, strontium or barium, more preferably the carbonate of calcium. For example used in reactant is that the fluorine that calcium carbonate and alumina will be generated by the decomposition of fluorine compounds jointly is fixed as CaF in the situation of calcium carbonate₂Thereby, prevented fluoridizing of alumina, so alumina has kept the function (activity) of decomposing fluorine compounds.

In alkaline earth metal compound, similar with alumina, the alkali metal content that exists as impurity is preferably 0.1 quality % or following, is preferably 0.01 quality % or following, more preferably 0.001 quality % or following. The particle diameter of alkaline earth metal compound is 100 μ m or following, is preferably 30 μ m or following, the alkaline earth metal compound of more preferably 5 μ m or following, and use powder morphology. Used alkaline earth metal compound and alumina all have 100 μ m or following particle diameter, this is because each raw material all is micro mist, be easy to disperse each other, the specific area of each raw material increases, make alumina and the alkaline earth metal compound can infinite approach and contact with each other, thereby increased fluorine that the decomposition by fluorine compounds on the alumina surface generates and the chance of alkaline earth metal compound reaction. Therefore, the specific area of alkaline earth metal compound is preferably 5m²/ g or more than. The instantiation of the calcium carbonate raw material that can particularly preferably use comprises powdered whiting (obtaining by crushed limestone), precipitated calcium carbonate (also claim winnofil, obtain by pass into carbon dioxide in milk of lime) and the quick lime and the white lime that neutralize with carbonic acid. Wherein preferably has low concentration such as the precipitated calcium carbonate of the impurity such as alkali metal, more preferably purity calcium carbonate.

How at low temperatures the reactant of the present invention mechanism of decomposing fluorine compounds also not fully aware of. But, because metal oxides such as iron oxide and manganese oxide exerts an influence hardly, during when a kind of alumina and a kind of alkaline earth metal compound, particularly when the carbonate coexistence of a kind of alumina and a kind of alkaline-earth metal, think a kind of special composite effect has occured.

The oxide of copper, tin, nickel, cobalt, chromium, molybdenum, tungsten or vanadium is described below, and it is the another kind of component of reactant of the present invention.

Can in reactant, add at least a metal oxide, be selected from the group that is formed by cupric oxide, tin oxide, nickel oxide, cobalt oxide, chromium oxide, molybdenum oxide, tungsten oxide and vanadium oxide. Preferably cupric oxide, tin oxide and vanadium oxide, more preferably cupric oxide and tin oxide in these metal oxides. Although metal oxide is considered to also to play the effect of the co-catalyst of decomposing fluorine compounds, but for example when in reactant, use cupric oxide or tin oxide, when it is coexisted with alumina and a kind of alkaline earth metal compound, according to the difference of fluorine compounds kind, decomposing the carbon monoxide that generates can be oxidized to carbon dioxide under low oxygen partial pressure.

Be similar to the raw material of above-mentioned reactant, the alkali metal content that exists as impurity in the metal oxide is 0.1 quality % or following, is preferably 0.01 quality % or following, more preferably 0.001 quality % or following. The particle diameter of metal oxide is preferably 100 μ m or following, is preferably 30 μ m or following, the metal oxide of more preferably 5 μ m or following, and use powder morphology.

The manufacture method of reactant of the present invention is described below.

Method for decomposing fluorine compounds according to the present invention comprises a kind of use of reactant, and this reactant comprises alumina and a kind of alkaline earth metal compound. Alumina is preferably 1: 9 to 1: 1 with the content ratio of alkaline earth metal compound in the reactant, is preferably 1: 4 to 2: 3, represents with mass ratio. Alumina in the reactant when coexisting with alkaline earth metal compound, decomposing fluorine compounds effectively, the content of alumina can change with the process of decomposition reaction. But, at least in the initial period of decomposition reaction, the content of alumina be preferably 0.1 or more than, represent that with its mass ratio to the total overall reaction agent latter's quality is got and done 1. If this mass ratio is less than 0.1, the decomposition of fluorine compounds may not can be carried out satisfactorily, and if the content of alumina surpasses 0.5 mass ratio, the amount of alkaline earth metal compound has reduced in ratio, effective usage factor of reactant has also reduced.

The content ratio of metal oxide is preferably 1: 99 to 5: 95, represents with its ratio to alumina and alkaline earth metal compound gross mass. If this mass ratio is too small, then can not be effective, and if ratio is excessive, alumina is relative with the total amount of alkaline earth metal compound have been reduced, therefore the effect of metal oxide is saturated, can not effectively carry out the decomposition of fluorine compounds.

The reactant that the present invention is used for decomposing fluorine compounds can by with above-mentioned mass ratio alumina and alkaline earth metal compound mixing being prepared, if necessary, also add metal oxide, and can be used as it is. Here, the preferred moisture that reduces as far as possible in each raw material. Moisture in the reactant is preferably 1 quality % or following.

Reactant also can be by being prepared the raw material granulation, and can use the form of its particle. When granulation forms reactant, can add entry, perhaps the difference according to raw material particle size adds entry and a kind of binder. Binder is had no particular limits, as long as it does not exert an influence to the raw material of institute's fusion, its addition can be 0.03 to 0.05, represents with its mass ratio to institute's fusion raw material gross mass, and the latter gets and does 1.0. Binder is preferably the micro mist alumina. By adding the micro mist alumina, the dispersibility of each raw material is improved, and can also overcome the difficulty in the alkaline earth metal compound granulation. In the alumina that adds as binder, particle diameter is preferably 0.1 μ m or following, is preferably 0.1 quality % or following as the contained alkali metal content of impurity, is preferably 0.01 quality % or following. The favourable part of this micro mist alumina is, even also can be effective on a small quantity, the relative amount of the active principle of per unit volume reactant is not almost reduced. But, as long as binder does not affect the ability of gained reactant, all be hard-core to kind and the consumption of binder.

As mentioned above, every kind is blended in raw material in the reactant, comprises the micro mist alumina that adds as binder, all preferably contains 0.1 quality % or following alkali metal. If the alkali metal content in the reactant surpasses 0.1 quality %, reduced so the lip-deep active site of alumina, thereby reduced particularly the decomposition ratio of PFC, for example CF₄And C₂F ₆。

When making for particle reaction agent of the present invention, then each raw material of fusion adds suitable quantity of water and mediates, and will mediate the product granulation, obtains particle. As the necessary kneader of the preparation of this particle, should choosing can mix and granulation person simultaneously, but, also can use the machine that mixes separately with granulation. For example, when using Henschel mixer or vertical mixer, can mix simultaneously and granulation. But, also may be in Henschel mixer or V-Mixer mixed material, again in dish-type granulators or rotary drum granulator with mixture pelleting.

Then with particle at 100 to 200 ℃ such as inert gas or air dryings such as nitrogen, with transpiring moisture. The reason of the particle form of use reactant is the high de-agglomeration activity that obtains reactant, increases hardness, thereby prevents the broken or pulverizing in pack into reactor or operating process. For this reason, preferably further cure this particle. Or rather, granulation and dried product are such as inert gas or air bakings such as nitrogen, and stoving temperature is 400 to 700 ℃, is preferably 500 to 700 ℃. The reason of curing under 400 ℃ or above temperature is further to evaporate the water that adds in granulation process, improving degrading activity, and can further increase hardness. If stoving temperature surpasses 700 ℃, then the resolution ratio of reactant (activity) reduces, but not fully aware of this whether owing to the decomposition of alkaline earth metal compound (for example ). In other words, importantly 700 ℃ or following almost completely slough alumina in conjunction with water, and don't reduce the activity of reactant. The amount of moisture that moisture in the reactant after curing discharges when preferably heating in 550 ℃ of inert gases or air is 1 quality % or following. Cure and can carry out in continuous device, for example rotary kiln still also can fixedly carry out in the heating furnace.

As mentioned above, the present invention's reactant of being used for decomposing fluorine compounds comprises alumina and a kind of alkaline earth metal compound as necessary component. In the situation that generates carbon monoxide, reactant also can contain the oxide of at least a metal, and this metal is selected from the group that is comprised of copper, tin, nickel, cobalt, chromium, molybdenum, tungsten and vanadium, is carbon dioxide even also will make Oxidation of Carbon Monoxide under low oxygen partial pressure. Reactant is preferably particle form, to increase the chance that contacts with the fluorine compounds that decomposed. If particle diameter is excessive, then participate in relative minimizing of surface area of absorption and diffusion fluorine compound gas, it is lower that diffusion rate becomes. On the other hand, if particle diameter is too small, then participate in relative the increasing of surface area of absorption and diffusion fluorine compound gas, it is higher that diffusion rate becomes. But, the amount that increases pending gas can obtain larger pressure reduction, and the volume of reactor (reactor) etc. can not reduce. Therefore, the particle diameter of reactant is preferably 0.5 to 10mm, is preferably 1 to 5mm.

The following describes according to the method for decomposing fluorine compounds of the present invention.

When the reactant that is made by said method contacted under proper temperature with fluorine compounds, fluorine compounds were decomposed, and the chlorine atom that decomposition generates and/or fluorine atom are fixed on the reactant with the form of alkaline earth metal chloride and/or fluoride. Contain sulphur fluoride, for example SF at pending gas₆Situation under, decompose the sulphur atom generate and be fixed on the reactant with the form of alkali earth metal sulfate, so can control the generation of oxysulfide.

In other words, when using decomposition reaction agent of the present invention, fluorine compounds can be decomposed effectively, and can not discharge harmful catabolite gas, for example HF, SiF₄、COF ₂And SO_xDeng compound. But, in order to prevent in the gas after this class catabolite remains in decomposition, also necessary suitably conditioned reaction condition for example is with or without the existence of oxygen, the form of reactant and the delivery rate of pending gas in the concentration of fluorine compounds, the pending gas in reaction temperature, the pending gas. Wherein, reaction (initiation is decomposed) temperature is very important condition.

Reaction temperature is different because of the kind of fluorine compounds in the pending gas.

For example, PFC belongs to the fluorine compounds that are difficult to decompose.CF particularly ₄, C ₂F ₆Decompose Deng being difficult to most, concerning the decomposition that only depends on thermal decomposition, 1200 to 1400 ℃ high temperature is necessary.But, according to method of the present invention, they can decompose under 550 ℃ or above temperature.And, CHClF ₂Be a kind of HCFC, it can decompose under 200 ℃ or above temperature with method of the present invention.Decomposition temperature itself can change in sizable scope according to the difference of fluorine compounds kind.Therefore, importantly, reactor is arranged on best temperature according to the difference of institute's decomposition of chemical compounds kind.

Because reaction temperature is different because of the kind or the structure of compound, when pending gas contains multiple PFC or HFC, as the gas that from the etching of making semiconductor devices or cleaning step, discharges, with reaction temperature be arranged on 550 ℃ or more than so that all these fluorine compounds detoxifcations.Under the situation of for example using carbonate as alkaline earth metal compound, the carbon that derives from fluorine compounds is by the oxygen oxidation that carbonate decomposition discharged, mainly with CO ₂Discharge.According to the difference of fluorine compounds kind, may generate CO.But, be present in the pending gas by making oxygen, CO also is easy to be oxidized to CO by identical reactant ₂, can fully be detoxified.

In other words, the method that is used for decomposing fluorine compounds according to the present invention can make the gas that contains fluorine compounds by the reactor of reactant is housed like this, according to the capacity of decomposition of fluorine compounds, keeps decomposition temperature simultaneously.Even reaction atmosphere is a non-oxidizing atmosphere, also can achieve the goal fully.But, concerning reduce CO to acceptable concentration or following, processing is carried out in oxidizing atmosphere, contains 20 volume % or following oxygen in for example pending gas.In this atmosphere, CO also can be handled simultaneously.Oxygen concentration is 20 volume % or following, and this is because air is the preferred diluent gas that uses.Even oxygen concentration is higher than this scope, effect is also by saturated, and degrading activity also no longer raises.

Concentration to fluorine compounds in the pending gas has no particular limits, and but, from the rentability viewpoint, low excessively concentration is disadvantageous.On the other hand, if excessive concentration decomposes the heat the produced temperature that induces reaction and raise, but this can be different because of the kind of fluorine compounds, almost can not regulate and control the temperature in the reactor sometimes.Therefore, preferably with a kind of inert gas or a kind of gas (comprising air) that contains oxygen with pending gas dilution, the concentration that makes fluorine compounds is 0.01 to 10 volume %, is preferably 0.01 to 5 volume %, more preferably 0.01 to 3 volume %.In the time can removing the heat that decomposition produces certainly and can regulate and control reaction temperature, the concentration of fluorine compounds in the gas is had no particular limits.

By this way, concentration of oxygen in kind by fluorine compounds in the gas of considering to carry out resolution process and concentration, the pending gas, SV (space velocity), LV (linear velocity) and with the admixture of other gases, determine preferred reaction condition according to various situations.

Resolution process can utilize a kind of decomposer to carry out, this device comprise the reactor that above-mentioned reactant is housed, the pending gas access that is connected with inside reactor, reaction back emission gases from reactor outlet, hold the heating furnace of reactor and be used for furnace temp is risen to the thermal source of predetermined temperature, by a pipeline pending gas access is connected with the fluorine compound gas source.

Fig. 1 shows an example that is used to implement device of the present invention.Make constant carrier gas flow through nitrogen supply (NS) line 2 or air or oxygen supply line 3 in advance, the temperature sensor 7 and the thermostat unit 10 that utilize reactor 8 to have, with electric heater 11 reactant 12 that preheats district 9 and be contained in the downstream that is used to heat pending gas in the reactor 8 is heated to predetermined temperature, is adjusted to constant temperature then.

After being adjusted to predetermined temperature, by valve separately, from fluorine compound gas supply line 1 and nitrogen supply (NS) line 2 or air or oxygen supply line 3 pending gas of introducing to hybrid chamber and connection socket 4.In reactor 8, introduce pending gaseous mixture by gas inlet pipe 6.The pending gas of introducing reactor 8 and heating in preheating district 9 contacts with the reactant that is heated to predetermined temperature, thereby decomposes.After the decomposition, the gas (waste gas) handled is cooled to predetermined temperature (water cooling or air cooling all can) with cooler 14, emits from delivery pipe 16.Concerning gas sample, pending gas 5 sample taps and processing back gas 15 sample taps can be positioned near the entrance and exit of reactor 8, thereby can analyze the component of each gas.

Fluorine compounds in the pending gas itself almost can (be decomposed ratio near 100%) fully and be decomposed.Fluorine component in the fluorine compounds after the decomposition is with stable alkali earth metal fluoride, as CaF ₂Form be fixed on the reactant, carbon component major part is with CO ₂Form with diluent gas, be discharged away as nitrogen.Therefore, the gas of handling is harmless, is substantially free of residual harmful substance, for example fluorine component or carbon monoxide.

When existing reactant exhausted, decomposition reaction stopped.The terminal point of decomposition reaction is known to be the time that detects fluorine compounds first.Fluorine compounds can decompose in batch system, when detecting fluorine compounds and reactant and lose degrading activity, the device shut-down operation is after the reactant of newly packing into, perhaps in same apparatus, exchange former reactor with the standby reactor that reactant is housed in advance in order, restart decomposition reaction.

In order to use this batch system continuously, also can adopt the multitower switched system, the reactor of some same types arranged side by side in this system, operate another reactor in the reactant in reactor of exchange, perhaps exchange former reactor with the reactor that reactant is housed separately in advance, when a reactor shut-down operation, the gas passage is transformed into another reactor.And, when device therefor being designed to have continuously or intermittently to reactor supply reactant with during the function of the reactant that discharging was used from reactor continuously or intermittently, operation can be carried out the long period on identical device continuously.

As mentioned above, according to the present invention, fluorine compounds can efficiently be decomposed, and the gas that is discharged is substantially free of residual harmful substance, for example fluorine component or carbon monoxide.Fluorine compounds described here be a kind of can be in making the process of semiconductor devices as the etching gas in the etch step or the compound of the purge gas in the cleaning step, it is at least a fluorine compounds, is selected from the group of being made up of perfluocarbon, hydrofluorocarbons, cfc, hydrogen cfc, perfluorinated ethers, hydrofluorination ether, fluorinated olefins and sulphur fluoride.The present invention is the method that is used for producing the semiconductor devices, comprise and use etching or the cleaning step of above-mentioned fluorine compounds as etching or purge gas, the reactant that comprises alumina and a kind of alkaline earth metal compound with use decomposes from the decomposition step of the gas that contains fluorine compounds of this etching or cleaning step discharging, and wherein this gas that contains fluorine compounds can efficiently be decomposed and detoxify.

Being used for producing the semiconductor devices, in the method as LSI and TFT, forming thin film or thick film, form circuit pattern by etching then with CVD method, sputtering method or vacuum vapor deposition method.In the device that is used to form film or thick film, clean, to remove the unnecessary deposit that is accumulated on device inwall or the anchor clamps.The unnecessary deposit of being accumulated causes the generation of particle, therefore in order to form good film, must remove this deposit.

For example use the etching method of above-mentioned fluorine compounds under different dry etching conditions, to carry out, for example plasma etching and microwave etching., except those fluorine compounds, for example also may contain from the gas of etch step discharging such as SiF ₄And COF ₂Deng compound or such as gases such as hydrogen chloride and hydrogen fluoride.But as mentioned above, the reactant of the application of the invention, the gentle body of these compounds can be decomposed simultaneously, and chlorine or fluorine atom can be fixed to the chloride or the fluoride of alkaline-earth metal, and perhaps carbon atom can be broken down into carbon dioxide, so detoxified.

According to the difference of fluorine compounds kind, may generate CO.But, by make oxygen in decomposition step with pending gas coexistence, CO can be easy to be oxidized to CO ₂So, can fully be detoxified.

And method of the present invention can be used in to be made as JP-A-10-12605 and the described semiconductor devices of JP-A-2000-58840.

For a more detailed description to the present invention below with reference to embodiment, but, the present invention should not be interpreted as only limiting to this.Unless this paper has explanation in addition, all percentage, part ratio etc. are all by weight.

The preparation example of reactant

The various raw materials of used reactant are as shown in table 1 in the test.

Table 1

The reactant material name	Particle diameter (μ m)	Specific area (m 2/g)	Impurity (quality %)
							Na	K	Fe	Si
			CaCO 3-a (purity calcium carbonate)	40	-	0.0012					0.0005	＜0.0001	＜0.0001
CaCO 3-b (precipitated calcium carbonate)	50	-					0.0056	0.0008	0.0010	0.001
			CaCO 3-c (powdered whiting)	45	-	0.0104					0.0027	0.0050	0.09
SrCO 3(strontium carbonate)	-	-					0.0107	0.001	0.005	-
			Al 2O 3-a[AlO (OH)] (pseudobochmite alumina)	60	241	0.0027					＜0.001	Fe 2O 30.0034	SiO 20.0066
Al 2O 3-b[Al 2O 3] (under 550 ℃, cure 3 hours Al 2O 3-a)	-	173					-	-	-	-
			Al 2O 3-c (activated bauxite)	10	255	0.067					＜0.001	Fe 2O 30.03	SiO 20.01
Al 2O 3-d (activated bauxite)	5	201					0.28	＜0.001	Fe 2O 30.01	SiO 20.01
			CuO (cupric oxide)	4-10	-	＜0.01					＜0.01	＜0.01	＜0.05
SnO 2(tin ash)	4-10	-					＜0.01	＜0.01	＜0.01	＜0.05
			V 2O 5(vanadic anhydride)	4-10	-	＜0.01					＜0.01	＜0.01	＜0.05
Cr 2O 3(chromium oxide)	10	-					＜0.01	＜0.01	＜0.01	-
			Binder I (ultra micro powder alumina)	＜0.1	-	＜0.001					＜0.001	＜0.001	＜0.001
Binder II (clay)	50	-					Na 2O 0.06	K 2O 0.07	Fe 2O 32.13	SiO 257.73

In the table 1, about identical reactant raw material, alphabetic flag (CaCO for example ₃-a) or the Arabic numerals mark be attached to behind the chemical formula to distinguish the grade of material.The material of the table 2 that this differentiation also is applicable to expression embodiment and Comparative Examples in 6.

Use material shown in the table 1 as raw material, make particle diameter and be 0.85 to 2.8mm particle.Or rather, for example material shown in table 2 experimental condition 1 and binder fusion mix in the Henschel mixer, after wherein adding entry, and granulation.The gained particle descended dry 3 hours at 110 ℃, sieved then.Every kind of particle of gained dewaters in air atmosphere and cures 3 hours by the heat treatment (electrothermal furnace) under the stoving temperature of 550 ℃ or 700 ℃, the preparation feedback agent, and condition is shown in the experimental condition 2 of table 2.

The reaction example

Use and carry out method of the present invention with the device of the identical configuration of device shown in Figure 1.That is to say, can lean on the circulatory stove (electrical power: 1.4KW of electric current along having by the heating element heater (siderochrome aluminum series alloy) of heat production, length: 400mm) Zhou center, run through and comprise invar 600 (inconel) (or SUS310S) and internal diameter is the reaction tube of 16mm, long 500mm, the 35ml that packs in the stove central authorities of reaction tube is used for the reactant of decomposing fluorine compounds.

Use fluorine compounds to be decomposed, as shown in Figure 1, after wherein adding oxygen, perhaps do not add oxygen, use nitrogen in above-mentioned reaction tube, to introduce fluorine compounds as carrier gas.The condition of this moment is as follows.

The flow velocity of pending gas: 0.201/ minute

The concentration of fluorine compounds in the pending gas: 0.5 to 3 volume %

The space velocity of pending gas: 343 hours-1

The linear velocity of pending gas: 1.0m/ minute

Concentration of oxygen in the pending gas: 20 volume % or following

In some test, allow HF, SiF ₄Or CO gas and pending gas coexistence, perhaps connect each reaction tube.

In each embodiment, introduce pending gas in beginning to heating element heater energising back, regulate the magnitude of current of circular heating furnace simultaneously, make the temperature of measuring by galvanic couple can remain on predetermined temperature, this thermoelectric couple is inserted into the center (reaching the position of maximum temperature in the reactant integral body) of reactant.In each form, reaction temperature is represented this temperature that is kept in course of reaction.

Pending gas and the gas of handling are taken a sample and composition analysis from sample tap separately shown in Figure 1.O ₂, N ₂, CO, CO ₂Analyze with gas analyzer with fluorine compounds, the F ion is to carry out sampling and analysing in containing the fluorine absorption bottle of sodium hydroxide solution.

Table 2 to reactant composite shown in 6 experimental conditions 1 (combination of each material) and binder corresponding to each material name of reactant shown in the table 1.For example, purity calcium carbonate is expressed as CaCO ₃-a, the pseudobochmite alumina is expressed as Al ₂O ₃-a, ultra micro powder alumina binder is expressed as binder I.By adding mass ratio is that 0.05 binder I or mass ratio are that 0.1 binder II makes reactant, supposes that the quality after alumina and the alkaline earth metal compound fusion is 1.0.Use table 2 to reactant shown in 6 experimental conditions 1 carries out the decomposition run based on experimental condition 2.The result with introduce behind the pending gas the per hour decomposition of fluorine compounds than and handle after gas in the CO that contained or concentration (volume %) expression of F ion.

Decompose ratio=(concentration of fluorine compounds in the gas in the pending gas after the concentration-processing of fluorine compounds) ÷ (concentration of fluorine compounds in the pending gas) * 100 (%)

Embodiment 1 to 3

Use the reactant that different alumina and calcium carbonate mix proportions are arranged as shown in table 2, carry out CF ₄Decomposition reaction.Used alumina is that the pseudobochmite alumina (is designated hereinafter simply as " Al ₂O ₃-a "), used alkaline earth metal compound is that purity calcium carbonate (is designated hereinafter simply as " CaCO ₃-a ").Reaction temperature is constant in 650 ℃, and oxygen concentration is arranged on 3.5 volume %.

The gained result is as shown in table 2.Under any mix proportions, introduce behind the pending gas in 3 hours the resulting decomposition ratio and be 99% or more than.And, as shown in table 2, almost do not detect F ion or CO in the gas after the processing of embodiment 1.

Embodiment 4 to 6

Change reaction temperature, use the reactant that under the condition identical, prepares to carry out CF with embodiment 2 ₄Decomposition reaction.The result is as shown in table 2.After introducing pending gas in 5 hours, gained under 600 ℃ the reaction temperature decompose than be 99% or more than, 700 ℃ of following gained decomposition than be 99.9% or more than.

Embodiment 7

Under the condition identical, carry out CF with embodiment 6 ₄Decomposition reaction, but the stoving temperature of reactant changes 550 ℃ to 700 ℃ into.The gained result is as shown in table 2.CF ₄Decomposition is than being identical, also be 99% or more than, but, compare with embodiment 6, decompose than reducing gradually.

Embodiment 8 and 9

Under the condition identical, carry out CF with embodiment 2 and embodiment 7 ₄Decomposition reaction, (be designated hereinafter simply as " Al but the alumina in the reactant changes the pseudobochmite alumina that cured 3 hours under 550 ℃ ₂O ₃-b ").Among the embodiment 8, also carried out using the decomposition reaction of the reactant that wherein is added with binder II.The result is as shown in table 2.The decomposition of embodiment 8 is more identical with embodiment 2 than almost, and illustrating between the different binders does not have difference.Among the embodiment 9, stoving temperature and reaction temperature all are arranged on 700 ℃, test, can keep higher decomposition ratio in the mode identical with embodiment 7.

Table 2

Embodiment	Experimental condition 1			Experimental condition 2			Result of the test
												Reactant (combination of material and mix proportions)		Binder	Stoving temperature (℃) amount (ml) of reactant	Reaction temperature (℃) oxygen concentration (volume %)	The kind of fluorine compounds and concentration (volume %)	The decomposition of fluorine compound gas is fluorinion concentration than (%) in () in the aging reprocessed gas, is CO concentration (volume %) in []
	Form (combination of material)	Mix proportions (mass ratio of material)	1 hour	2 hours	3 hours	4 hours	5 hours
								1	Al 2O 3-a/CaCO 3-a	0.19/0.81	I	550 35	650 3.5					CF 4 3.0	＞99.9 [＜0.001]	＞99.9 [＜0.001]	＞99.9 [＜0.001]	99.1 [＜0.001]	95.9 (＜0.0001)
2	Al 2O 3-a/CaCO 3-a	0.30/0.70	I	＞99.9	＞99.9	＞99.9	99.7							97.6
								3	Al 2O 3-a/CaCO 3-a	0.45/0.55	I				＞99.9	＞99.9	＞99.9		98.8	60.4
4	Al 2O 3-a/CaCO 3-a	0.30/0.70		550 35	550 3.5	CF 4 3.0	82.2							82.0							81.3	78.0	68.0
								5	Al 2O 3-a/CaCO 3-a	0.30/0.70	I	550 35	600 3.5		99.8	99.7	98.8	94.7	89.1
6	Al 2O 3-a/CaCO 3-a	0.30/0.70	I	550 35	700 3.5		＞99.9							＞99.9						＞99.9	＞99.9	99.9
								7	Al 2O 3-a/CaCO 3-a	0.30/0.70	I	700 35	700 3.5		CF 4 3.0	＞99.9	＞99.9	99.8	99.0				94.0
8	Al 2O 3-b/CaCO 3-a	0.30/0.70	I II	550 35	650 3.5	CF 4 3.0	＞99.9 ＞99.9							＞99.9 ＞99.9						＞99.9 ＞99.9	99.4 99.5	94.9 94.6
								9	Al 2O 3-b/CaCO 3-a	0.30/0.70	I	700 35	700 3.5		＞99.9	＞99.9	＞99.9	＞99.9	99.6

Embodiment 10 to 13

Under the condition identical, carry out CF with embodiment 2 and embodiment 6 ₄Decomposition reaction, (be designated hereinafter simply as " CaCO but the calcium carbonate in the reactant changes precipitated calcium carbonate into ₃-b ") or powdered whiting (be designated hereinafter simply as " CaCO ₃-c ").The gained result is as shown in table 3.Can see CF ₄Decomposition than total amount corresponding to impurity in every kind of calcium carbonate shown in the table 1, and be reduction trend: CaCO according to following order ₃-a (embodiment 2 and 6)＞CaCO ₃-b (embodiment 10 and 11)＞CaCO ₃-c (embodiment 12 and 13).

Embodiment 14 to 16

Under the condition identical, carry out CF with embodiment 13 ₄Decomposition reaction, but the alumina in the reactant changes the (Al of alumina shown in the table 1 into ₂O ₃-b, Al ₂O ₃-c or Al ₂O ₃-d).The gained result is as shown in table 3.Can see CF ₄Decomposition than corresponding to every kind of Al ₂O ₃In the amount of impurity, and be reduction trend: Al according to following order ₂O ₃-a (embodiment 13) 〉=Al ₂O ₃-b (embodiment 14)＞Al ₂O ₃-c (embodiment 15)＞Al ₂O ₃-d (embodiment 16).

Embodiment 17

Under the condition identical, carry out decomposition reaction, but fluorine compounds are from CF with embodiment 1 ₄Change C into ₂F ₆The gained result is as shown in table 3.C in 3 hours after introducing pending gas ₂F ₆The decomposition ratio reached 80% or more than.

Embodiment 18 to 20

Under the condition identical, carry out C with embodiment 2 ₂F ₆Decomposition reaction, but changed reaction temperature and oxygen concentration.The gained result is as shown in table 3.Among the embodiment 18, reaction temperature and oxygen concentration are separately positioned on 600 ℃ and 3.5 volume %, but, and C ₂F ₆Decomposition be on the identical level than with embodiment 17, the effect that control CO generates is not high enough.

Among the embodiment 19 and 20, change reaction temperature into 650 ℃, oxygen concentration changes 0 volume % or 20 volume % into, carries out decomposition reaction.In these two embodiment, C in 3 hours after introducing pending gas ₂F ₆The decomposition ratio reached 90% or more than.Generate 3% CO among the embodiment 19 approximately, and after introducing pending gas, also do not detected CO in 3 hours among the embodiment 20.Find out thus, allow oxygen to have the generation that almost entirely to control CO.

Table 3

Embodiment	Experimental condition 1			Experimental condition 2			Result of the test
												Reactant (combination of material and mix proportions)		Binder	Stoving temperature (℃) amount (ml) of reactant	Reaction temperature (℃) oxygen concentration (volume %)	The kind of fluorine compounds and concentration (volume %)	The decomposition of fluorine compound gas is fluorinion concentration than (%) in () in the aging reprocessed gas, is CO concentration (volume %) in []
	Form (combination of material)	Mix proportions (mass ratio of material)	1 hour	2 hours	3 hours	4 hours	5 hours
								10	Al 2O 3-a/CaCO 3-b	0.30/0.70	I	550 35	650 3.5					CF 4 3.0	＞99.9	＞99.9	99.5	99.0	98.5
11	Al 2O 3-a/CaCO 3-b	0.30/0.70	I	700 3.5	＞99.9	＞99.9	＞99.9							99.6	94.9
								12	Al 2O 3-a/CaCO 3-c	0.30/0.70	I		550 35			650 3.5	CF 4 3.0		＞99.9	＞99.9	98.8	94.7	-
13	Al 2O 3-a/CaCO 3-c	0.30/0.70	I	700 3.5	＞99.9	＞99.9	＞99.9					99.9		-
								14	Al 2O 3-b/CaCO 3-c	0.30/0.70	I				550 35	700 3.5		CF 4 3.0	＞99.9	＞99.9	99.9	99.4	-
15	Al 2O 3-c/CaCO 3-c	0.30/0.70	＞99.9	99.7	97.8	89.4	-
								16	Al 2O 3-d/CaCO 3-c	0.30/0.70		32.9	27.4	-			-		-
17	Al 2O 3-a/CaCO 3-a	0.19/0.81	I	550 35	650 3.5	C 2F 6 3.0	85.8 [0.021]													84.9 [0.020]	82.8 [0.020]	75.2 [0.088]	62.5 [0.182]
								18	Al 2O 3-a/CaCO 3-a	0.30/0.70	600 3.5	86.5 [0.14]	84.9 [0.13]	81.2 [0.52]	70.2 [0.60]	49.7 [0.47]
19	Al 2O 3-a/CaCO 3-a	0.30/0.70			I		550 35										650 0	C 2F 6 3.0	98.3 [2.77]	97.4 [2.74]	89.2 [3.16]	73.3 [2.04]	45.7 [1.32]
			20	Al 2O 3-a/CaCO 3-a		0.30/0.70		I	650 20.0	99.2 [＜0.001]	97.4 [＜0.001]	91.3 [＜0.001]	72.2 [0.006]	35.5 [0.080]

Embodiment 21 to 24

Under the condition identical, carry out C with embodiment 20 ₂F ₆Decomposition reaction, but used reactant is by to Al ₂O ₃-a/CaCO ₃-a mass ratio is to add a kind of metal oxide (embodiment 21:V in the reactant of 0.3/0.7 ₂O ₅, embodiment 22:SnO ₂, embodiment 23:CuO+SnO ₂, embodiment 24:Cr ₂O ₃) obtain, and change oxygen concentration into 3.5 volume % from 20 volume %.The gained result is as shown in table 4.C ₂F ₆Decomposition than almost with the coming to the same thing of embodiment 18 to 20, even but having concentration is the oxygen of 3.5 volume %, almost do not detect CO yet.Find out thus, by in reactant, adding a kind of metal oxide, even under low oxygen partial pressure also oxidation CO almost entirely.

Embodiment 25 and 26

Under the condition identical, carry out CF with embodiment 2 ₄With C ₂F ₆The decomposition reaction of gaseous mixture, (reaction reagent 35 * 2=70ml), reaction temperature also change 550 ℃ or 650 ℃ into but connect the reaction tube of two units.The gained result is as shown in table 4.Reaction temperature is among 550 ℃ the embodiment 25, C ₂F ₆Decomposition more about 70% than being low to moderate, but C ₂F ₆With CF ₄Decomposition than all keeping almost constant.Reaction temperature is among 650 ℃ the embodiment 26, CF ₄With C ₂F ₆Can both keep the high de-agglomeration ratio.

Embodiment 27 and 28

Under the condition identical, carry out CF with embodiment 2 ₄Decomposition reaction, but CO coexistence or HF and SiF ₄Coexistence.The gained result is as shown in table 4.Among the embodiment 27 of CO coexistence, CO, HF and SiF are not then arrived in inspection in the gas of handling ₄Among the embodiment 28 of coexistence, the F ion is not then arrived in inspection in the gas of handling.

Embodiment 29 to 39

Change kind and the concentration and the reaction temperature of fluorine compounds, under the condition identical, carry out decomposition reaction with embodiment 2.The result is as shown in table 5.Under the situation of not considering reaction temperature, all fluorine compounds have all reached higher decomposition ratio.The structure of embodiment 31 to 39 used fluorine compounds is as follows.

Embodiment 31 CF ₂=CF ₂Embodiment 32 CHClFCF ₃

Embodiment 33 CClF ₂CClF ₂Embodiment 34 CH ₂FCF ₃

Embodiment 35 CF ₃OCHFCF ₃Embodiment 36 CF ₃OCF=CF ₂

Embodiment 37 Embodiment 38

Embodiment 39

Embodiment 40

Under the condition identical, carry out CF with embodiment 2 ₄Decomposition reaction, but the CaCO in the reactant ₃Change SrCO into ₃The gained result is as shown in table 5.Although at SrCO ₃Situation under, decompose than slight reduction is arranged, this reactant also can be as the reactant of decomposing fluorine compounds.

Comparative Examples 1 and 2

Test in the mode identical at aspects such as the preparation of reactant, reaction examples with embodiment.

Use the reactant that only comprises alumina, under experimental condition as shown in table 6, carry out CF ₄Decomposition reaction.As a result, 2 hours reaction reduces than unexpected after introducing pending gas.

Comparative Examples 3 and 4

Preparation feedback agent under the condition identical with embodiment 2, but MnO in reactant, used ₂Or Fe ₂O ₃Replaced C aCO ₃, CF ₄Decomposition reaction under 700 ℃, carry out.The gained result is as shown in table 6.In each example, decomposing ratio is exactly low from beginning.

Table 4

Embodiment	Experimental condition 1			Experimental condition 2			Result of the test
												Reactant (combination of material and mix proportions)		Binder	Bake and bank up with earth temperature (℃) amount (ml) of reactant	Reaction temperature (℃) oxygen concentration (volume %)	The kind of fluorine compounds and concentration (volume %)	The decomposition of fluorine compound gas is to be CO concentration (volume %) in the fluorinion concentration [] in () than (%) in the aging reprocessed gas
	Form (combination of material)	Mix proportions (mass ratio of material)	1 hour	2 hours	3 hours	4 hours	5 hours
								21	V 2O 5Join example 20	O.97/0.03	I	550 35	650 3.5					C 2F 6 3.0	99.0 [＜0.001]	97.4 [＜0.001]	90.3 [0.001]	72.3 [0.006]	35.0 [0.010]
22	SnO 2Join example 20	0.97/0.03	99.0 [＜0.001]	96.7 [＜0.001]	91.5 [＜0.001]	72.0 [0.024]	40.3 [0.023]
								23	CuO+SnO 2Join example 20	0.98/0.005+0.015				I	98.9 [＜0.001]	97.3 [＜0.001]	91.2 [＜0.001]		73.2 [＜0.001]	36.3 [＜0.001]
24	Cr 2O 3Join example 20	0.97/0.03	I	98.7 [＜0.001]	97.0 [＜0.003]	90.1 [0.027]	72.7 [0.047]				38.6 [0.030]
								25	Al 2O 3-a/CaCO 3-a	0.30/0.70				I	550 35×2	550 3.5	CF 4 1.5 C 2F 6 1.5		99.7 68.9	99.7 68.9	99.7 68.9	99.5 62.9	99.4 62.8
26	Al 2O 3/CaCO 3-a	0.30/0.70	I	650 3.5	CF 4 1.5 C 2F 6 1.5	＞99.9 ＞99.9	＞99.9 ＞99.9				＞99.9 ＞99.9	＞99.9 99.8	＞99.9 99.5
								27	Al 2O 3-a/CaCO 3-a	0.30/0.70				I		550 35	650 3.5	CF 4 3.0 CO 0.5	＞99.9 [＜0.001]	＞99.9 [＜0.001]	＞99.9 [＜0.001]	99.8 [＜0.001]	90.2 [＜0.001]
28	Al 2O 3-a/CaCO 3-a	0.30/0.70	I	CF 4 0.5 HF 0.5 SiF 4 0.5	＞99.9 (＜0.0001)	＞99．9 (＜0.0001)	＞99.9 (＜0.0001)				＞99.9 (＜0.0001)	＞99.9 (＜0.0001)

Table 5

Embodiment	Experimental condition 1			Experimental condition 2			Result of the test
												Reactant (combination of material and mix proportions)		Binder	Stoving temperature (℃) amount (ml) of reactant	Reaction temperature (℃) oxygen concentration (volume %)	The kind of fluorine compounds and concentration (volume %)	The decomposition of fluorine compound gas is fluorinion concentration than (%) in () in the aging reprocessed gas, is CO concentration (volume %) in []
	Form (combination of material)	Mix proportions (mass ratio of material)	1 hour	2 hours	3 hours	4 hours	5 hours
								29	Al 2O 3-a/CaCO 3-a	0.30/0.70	I	550 35	200 3.5					CHClF 2 0.5	＞99.9	＞99.9	＞99.9	＞99.9	＞99.9
30	Al 2O 3-a/CaCO 3-a	0.30/0.70	I	350 3.5	CHF 3 0.5	＞99.9	＞99.9							＞99.9	＞99.9	＞99.9
								31	Al 2O 3-a/CaCO 3-a	0.30/0.70	I		200 3.5				C 2F 4 0.5	＞99.9	＞99.9	＞99.9	＞99.9	＞99.9
32	Al 2O 3-a/CaCO 3-a	0.30/0.70	I	300 3.5	C 2HClF 4 0.5	＞99.9	＞99.9							＞99.9	＞99.9	＞99.9
								33	Al 2O 3-a/CaCO 3-a	0.30/0.70	I		500 3.5				C 2Cl 2F 4 0.5	＞99.9	＞99.9	＞99.9	＞99.9	＞99.9
34	Al 2O 3-a/CaCO 3-a	0.30/0.70	I	C 2H 2F 4 0.5	＞99.9	＞99.9	＞99.9							＞99.9	＞99.9
								35	Al 2O 3-a/CaCO 3-a	0.30/0.70	I					200 3.5	C 3HF 7O 0.5	＞99.9	＞99.9	＞99.9	＞99.9	＞99.9
36	Al 2O 3-a/CaCO 3-a	0.30/0.70	I	C 3F 7O 0.5	＞99.9	＞99.9	＞99.9						＞99.9	＞99.9
								37	Al 2O 3-a/CaCO 3-a	0.30/0.70	I				600 3.5		C 4F 8 0.5	＞99.9	＞99.9	＞99.9	＞99.9	＞99.9
38	Al 2O 3-a/CaCO 3-a	0.30/0.70	I	500 3.5	C 5F 8 0.5	＞99.9	＞99.9						＞99.9	＞99.9		＞99.9
								39	Al 2O 3-a/CaCO 3-a	0.30/0.70	I				600 3.5		SF 6 0.5	＞99.9	＞99.9	＞99.9	＞99.9	＞99.9
40	Al 2O 3-a/CaCO 3-a	0.30/0.70	I	650 3.5	CF 4 3.0	96.0	94.3						91.3	76.5		65.5

Table 6

Embodiment	Experimental condition 1			Experimental condition 2			Result of the test
												Reactant (combination of material and mix proportions)		Binder	Stoving temperature (℃) amount (ml) of reactant	Reaction temperature (℃) oxygen concentration (volume %)	The kind of fluorine compounds and concentration (volume %)	The decomposition of fluorine compound gas is fluorinion concentration than (%) in () in the aging reprocessed gas, is CO concentration (volume %) in []
	Form (combination of material)	Mix proportions (mass ratio of material)	1 hour	2 hours	3 hours	4 hours	5 hours
								1	Al 2O 3-a	1.0	I	550 35	650 3.5					CF 4 3.0	＞99.9 [＜0.001]	19.7 [＜0.001]	- -	- -	- -
2	Al 2O 3-b	1.0	I	700 35	750 0	CF 4 3.0	＞99.9 [＜0.005]							47.8 [0.003]	40.8 [＜0.001]	38.3 -	- -
								3	Al 2O 3-a/MnO 2	0.30/0.70	I	550 35	700 3.5					CF 4 3.0	8.5	3.0	-	-	-
4	Al 2O 3-a/Fe 2O 3	0.30/0.70	I	550 35	700 3.5	CF 4 3.0	43.4							32.3	-	-	-

Embodiment 41

Use a kind of etching gas etching oxidation silicon fiml, this gas comprises 20sccm CF ₄, 20sccm CHF ₃With the 400sccm argon gas.Use the nitrogen carrier gas, a part is introduced the device that the reactant identical with embodiment 23 be housed shown in Figure 1 from the gas of this dry etch step discharging.Begin the gas sample to the decomposer exit in back 3 hours in decomposition run, use gc analysis.As a result, CF ₄And CHF ₃Concentration all be 10 volume ppm or following, CO concentration also is 10 volume ppm or following.The fluorinion concentration water distributes ion chromatography analysis, and the result is 1 volume ppm or following.

As described herein, when using reactant of the present invention, fluorine compounds can effectively be decomposed by simple preparation under relatively low temperature, decompose the fluorine that is generated and can be fixed to harmless material.In other words, the present invention can enough simple decomposers, operate by simple processing and realize.Decomposition efficiency is higher, when allowing the oxygen coexistence, can also control the generation of carbon monoxide.And catabolite becomes a kind of stable alkali earth metal fluoride, for example CaF ₂, therefore, post processing is easy.And the effect that reduces the reactant cost is obviously higher.Particularly the present invention can go far towards the decomposition of the used fluorine compounds of manufacture process of semiconductor devices.

Although describe the present invention with reference to the specific embodiment, but it will be apparent to those skilled in the art that under the situation that does not deviate from its essence and scope, can carry out various variations and modification.

Claims (24)

1, the reactant that is used for decomposing fluorine compounds, comprise alumina, alkaline earth metal compound and metal oxide, described alkaline earth metal compound is the carbonate of magnesium, calcium, strontium or barium, described alumina and alkaline earth metal compound have 1: 9 to 1: 1 mass ratio, described metal oxide is to be selected from least a in the oxide of copper, tin, nickel, cobalt, chromium, molybdenum, tungsten and vanadium, the content of described metal oxide is represented with its ratio to the gross mass of described alumina and alkaline earth metal compound, is 1: 99 to 5: 95.

2, the reactant that is used for decomposing fluorine compounds as claimed in claim 1, the specific area of wherein said alumina is 50m ²/ g or more than.

3, as the reactant that is used for decomposing fluorine compounds of claim 1 or 2, wherein said alumina is the pseudobochmite alumina.

4, as the reactant that is used for decomposing fluorine compounds of claim 1 or 2, wherein said alumina is to obtain by cure the pseudobochmite alumina under 400 to 1000 ℃ stoving temperature.

5, as the reactant that is used for decomposing fluorine compounds of claim 1 or 2, wherein this alumina and alkaline earth metal compound are present in the described reactant with form of powder separately, and particle diameter is 100 μ m or following.

6,, contain 0.1 quality % or following a kind of alkali metal as the reactant that is used for decomposing fluorine compounds of claim 1 or 2.

7, as the reactant that is used for decomposing fluorine compounds of claim 1 or 2, it is by cure the granular disintegration that obtains under 400 to 700 ℃ temperature.

8, the reactant that is used for decomposing fluorine compounds as claimed in claim 7, it is that particle diameter is 0.5 to 10mm granular disintegration.

9,, contain 1 quality % or following water as the reactant that is used for decomposing fluorine compounds of claim 1 or 2.

10, as the reactant that is used for decomposing fluorine compounds of claim 1 or 2, wherein said fluorine compounds are at least a fluorine compounds that are selected from down group: perfluocarbon, hydrofluorocarbons, cfc, hydrogen cfc, perfluorinated ethers, hydrofluorination ether, fluorinated olefins, sulphur fluoride, SiF ₄And COF ₂

11, as the reactant that is used for decomposing fluorine compounds of claim 10, wherein said fluorine compounds contain hydrogen chloride, hydrogen fluoride or hydrogen chloride and hydrofluoric mixture.

12, the method that is used for decomposing fluorine compounds, comprise a kind of reactant and fluorine compounds are contacted under 200 ℃ or above temperature, wherein said reactant comprises alumina and a kind of alkaline earth metal compound, this alkaline earth metal compound is a magnesium, calcium, the carbonate of strontium or barium, and comprise and be selected from copper, tin, nickel, cobalt, chromium, molybdenum, at least a oxide in the oxide of tungsten and vanadium, described alumina and alkaline earth metal compound have 1: 9 to 1: 1 mass ratio, the content of described metal oxide is represented with its ratio to the gross mass of described alumina and alkaline earth metal compound, is 1: 99 to 5: 95.

13, as the method that is used for decomposing fluorine compounds of claim 12, wherein the concentration of these fluorine compounds in the gas processed by contacting with this reactant is 0.01 to 10 volume %.

14, the method that is used for decomposing fluorine compounds, comprise and make a kind of reactant and fluorine compounds under 500 ℃ or above temperature, in the presence of oxygen, contact, thereby the generation of control carbon monoxide, wherein said reactant comprises alumina and a kind of alkaline earth metal compound, this alkaline earth metal compound is a magnesium, calcium, the carbonate of strontium or barium, and comprise and be selected from copper, tin, nickel, cobalt, chromium, molybdenum, at least a oxide in the oxide of tungsten and vanadium, described alumina and alkaline earth metal compound have 1: 9 to 1: 1 mass ratio, the content of described metal oxide is represented with its ratio to the gross mass of described alumina and alkaline earth metal compound, is 1: 99 to 5: 95.

15, as the method that is used for decomposing fluorine compounds of claim 14, wherein the concentration of this oxygen in pending gas is 20 volume % or following.

16, as the method that is used for decomposing fluorine compounds of claim 12 or 14, wherein this reactant is fixedly become alkaline earth metal chloride, alkali earth metal fluoride and/or alkali earth metal sulfate respectively with chlorine atom, fluorine atom and/or the sulphur atom that fluorine compounds produce through contacting.

17, the method that is used for producing the semiconductor devices, comprise and use etching or the cleaning step of at least a fluorine compounds as etching gas or purge gas, these fluorine compounds are selected from by perfluocarbon, hydrofluorocarbons, cfc, the hydrogen cfc, perfluorinated ethers, hydrofluorination ether, the group that fluorinated olefins and sulphur fluoride are formed, also comprise and use the reactant that comprises alumina and a kind of alkaline earth metal compound to decompose from the decomposition step of the gas that contains these fluorine compounds of described etching or cleaning step discharging, this alkaline earth metal compound is a magnesium, calcium, the carbonate of strontium or barium, and described reactant also comprises and is selected from copper, tin, nickel, cobalt, chromium, molybdenum, at least a oxide in the oxide of tungsten and vanadium, described alumina and alkaline earth metal compound have 1: 9 to 1: 1 mass ratio, the content of described metal oxide is represented with its ratio to the gross mass of described alumina and alkaline earth metal compound, is 1: 99 to 5: 95.

18, as the method that is used for producing the semiconductor devices of claim 17, wherein the gas from described etching or cleaning step discharging is the gas that contains at least a fluorine compounds, and these fluorine compounds are selected from by perfluocarbon, hydrofluorocarbons, cfc, hydrogen cfc, perfluorinated ethers, hydrofluorination ether, fluorinated olefins, sulphur fluoride, SiF ₄And COF ₂The group of forming.

19, as the method that is used for producing the semiconductor devices of claim 18, the wherein said gas that contains fluorine compounds contains hydrogen chloride, hydrogen fluoride or hydrogen chloride and hydrofluoric mixture.

20, as the method that is used for producing the semiconductor devices of claim 17, wherein in described decomposition step, the fluorine compounds in the pending gas are to decompose under 200 ℃ or above temperature.

21, as the method that is used for producing the semiconductor devices of claim 17, wherein in described decomposition step, the fluorine compounds concentration in the pending gas is 0.01 to 10 volume %.

22, as the method that is used for producing the semiconductor devices of claim 17, wherein this decomposition step is under 500 ℃ or above temperature, carries out in the presence of oxygen, thus the generation of control carbon monoxide.

23, as the method that is used for producing the semiconductor devices of claim 22, wherein in described decomposition step, the oxygen concentration in the pending gas is 20 volume % or following.

24, as the method that is used for producing the semiconductor devices of claim 17, wherein chlorine atom, fluorine atom and/or the sulphur atom that is produced in the decomposition step of the gas that uses this reactant decomposition to discharge from described etching or cleaning step fixedly become alkaline earth metal chloride, alkali earth metal fluoride and/or alkali earth metal sulfate respectively.

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