JP2023535850A - Separation of HF/HCl Containing Etching Exhaust Gas by FTrPSA and Recovery, Recycling and Reuse Method - Google Patents

Abstract

The present invention discloses a method for separating and recovering and recycling an etching exhaust gas containing HF/HCl using FTrPSA, and relates to the environmental protection field of recovering and recycling the effective components of an etching exhaust gas in a semiconductor process, the main steps of which are: HF/HCl-containing dry etching exhaust gas is sequentially subjected to pretreatment, chlorosilane/HCl spray absorption, medium temperature pressure swing adsorption, HF rectification, multi-stage evaporation/compression/condensation, HCl purification, weak cold rectification in chlorosilane, and exhaust gas absorption steps. HF and HCl product gases with a purity of 99.99% or higher are obtained and recycled back to the dry etching process. Medium temperature pressure swing adsorption is a two-stage PSA, and HF rectification is a two-stage PSA. HCl purification is rectification using two columns. According to the present invention, it is possible to separate and recover HF and HCl from the HF/HCl-containing dry etching exhaust gas, and to return them to the etching process for circulation use, thereby reducing the cost of etching gas raw materials and the environmental protection treatment of exhaust gas. has been significantly reduced, solving the problem of conventional technology in which exhaust gas is emitted only when it reaches the standard, making it impossible to realize comprehensive utilization of exhaust gas, and filling a gap in this technical field. [Selection diagram] Figure 1 JPEG2023535850000002.jpg64134

Description

The present invention relates to the environmental protection field of recovery and recycling of effective components of etching exhaust gas in semiconductor processes, and more specifically, separation and recovery of HF/HCl-containing etching exhaust gas by FTrPSA (Full Temperature Range Pressure Swing Adsorption). It relates to a cyclic reuse method.

Etching silicon (Si) or silicon carbide (SiC) based wafers or epitaxial thin films is the most critical step in the manufacturing process of chips such as semiconductor integrated circuits (ICs), among which fluorine (F), Plasma or conventional gas dry etching with compounds containing chlorine (Cl) is widely applied in the semiconductor industry. For example, integrated circuit (IC) fabrication typically includes steps such as deposition, masking, etching and stripping to form and connect circuit elements such as transistors, resistors and capacitors. In the IC manufacturing process, it is necessary to fabricate hundreds to thousands of chips at the same time on one wafer or epitaxial thin film sheet. Dimensions tend to be smaller and smaller. In response to the development needs of ultra large scale integrated circuit (ULSI) chips, etching technology tends to develop in the direction of larger area and smaller etching line width, among which gas dry etching, especially plasma gas dry etching It has already become the most widely applied and developed etching technology. Processing methods and equipment such as reactive ion etching (RIE), electron cyclotron resonance (ECR), helicon wave source (HWS) and inductively coupled plasma source (ICP), which have emerged in succession, have etching areas greater than 300 mm and etching line widths greater than 300 mm. It was born to meet the requirements of high resolution integrated circuits, such as sub-0.1 μm.

Etching (or Etch Film) is the process of selectively removing unwanted material from the surface of a silicon or silicon carbide based wafer or epitaxial thin film (abbreviated as "wafer") so that the adhesive is applied. The mask pattern is accurately transferred onto the processed wafer. Etching is divided into wet etching and dry etching, and plasma etching in dry etching has already become a mainstream etching method. Commonly used gases for dry etching are mainly hydrogen fluoride (HF), hydrogen chloride (HCl), carbon tetrafluoride ( _CF4 ), sulfur hexafluoride ( _SF6 ), nitrogen trifluoride ( _NF3) . ), carbon tetrachloride (CCl ₄ ) and other fluorine-based gases and Cl, Br groups are introduced, and hydrogen gas (H ₂ ), argon gas (Ar), oxygen gas ( O ₂ ), nitrogen gas (N ₂ ), etc. are used. In the plasma environment of the low pressure discharge, it reacts with Si or SiC on the wafer surface, and in the gas phase HF, HCl, silicon tetrafluoride (SiF ₄ ), silicon tetrachloride (SiCl ₄ ), and a small amount of silicon tetrabromide (SiBr _{4 )} . ), silane (SiH ₄ ), carbon monoxide (CO), carbon dioxide (CO ₂ ), water (H ₂ O), volatile organics (VOC), suspended fine silicon dioxide (SiO ₂ ), silicon (Si ) or particles such as silicon carbide (SiC) or an aerosol, and an etching exhaust containing H ₂ , N ₂ , Ar, and the like. The etching exhaust gas is a dangerous chemical gas with characteristics such as flammability, explosiveness, toxicity, and corrosiveness. It also needs to be a method that is technically and economically feasible and reduces production costs.

There are five main industrial methods for treating conventional etching exhaust gases: water washing, acid-base neutralization, oxidative combustion, adsorption and plasma combustion.

For the situation that the etching exhaust gas mainly contains highly acidic toxic contaminants, the water washing method uses water absorption and water gas conversion to absorb the acidic components to form a liquid, and convert the toxic contaminant components into non-toxic substances. Alternatively, it is a method of converting to sedimentation (water slurry) and realizing discharge. Although this method is simple and easy to operate and is commonly employed in industry, the absorption phase equilibrium and conversion efficiency are limited, and the absorption liquid formed has a very high corrosiveness. Exhaust gas still contains many acidic contaminants, which makes it very difficult to completely meet the emission standards. Emission standards can only be reached after The water washing method can also employ heated steam, and the high temperature converts harmful contaminants into harmless oxides, thereby increasing the cleaning efficiency of the water washing method. The main problem with the water washing method is that it consumes large amounts of water and produces secondary contaminants such as hydrofluoric acid, hydrochloric acid or fluorosilicic acid, which are difficult to recover and highly corrosive. This results in a large investment in processing equipment. At the same time, the high-fluorine or high-chlorine silicic acid formed by the water washing method forms a slurry with silicon or silicon dioxide particles and dust, which easily clogs equipment such as valves and pipes, and further decomposes when subjected to heat. There is a danger of corroding equipment and causing leaks. Further, the water washing method has a certain effect in the case where the exhaust gas contains many water-soluble harmful foreign matter components or the case where the exhaust gas easily undergoes a conversion reaction with water vapor.

In the acid-base neutralization method, a basic solution such as calcium hydroxide is added to the acidity of etching exhaust gas, and fluoride ions or HF therein are converted into calcium fluoride (CaF ₂ , i.e., artificial fluorite). ), or by precipitating or desorbing the high fluorine/high chlorine calcium silicate as a slurry, adding another basic solution to the unabsorbed gas, and desorbing the acidic contaminants therein. This is a method for allowing the amount of residual acidic foreign matter components in the exhaust gas to reach the emission standards. EDWARDS, a well-known company in the semiconductor industry, invented a gas reactor column (GRC), which is a chemical neutralization method and its device. is to process The column of the device is packed with a suitable mixture of inorganic fine particles, and after the column is heated to a certain temperature by energizing the column, the exhaust gas passes through the column and causes a neutralization reaction. A dry chemical reaction occurred in this gas reactor column, which can be directly connected to a vacuum system. The flue gas undergoes a sufficient chemical reaction with basic or metal basic substances in the column, part of the flue gas is converted into inert substances, and a part of the flue gas is adsorbed by the chemical reaction, resulting in the discharge of harmful flue gas. greatly reduced. However, since the gas column is frequently exchanged, adsorption of the exhaust gas is not complete, and the reaction column is deactivated, causing harmful components to pass through, which may lead to secondary pollution. Acid-base or chemical neutralization methods are still limited by absorption or chemisorption equilibria and require multi-stage or multi-column neutralization reactions in order to exhaust emissions exhaustively to meet emission standards, thus reducing costs. I have a problem that is high.

The oxidative combustion method utilizes flammable components such as _H2 , silane, silicon tetrafluoride, and organic substances (VOC) contained in the etching exhaust gas, and uses air or oxygen-containing compound gas at a sufficient temperature and time. is introduced into contact with flammable components and incinerated to allow the formation of oxides, which are subsequently cooled by heat exchange until the oxidation products condense and are discharged, and the residual gas is further rinsed with a basic solution. and remove the acidity of the waste gas. Since the etching exhaust gas contains many flame-retardant acidic gases such as HF and HCl, this method is not suitable for treating the etching exhaust gas. In particular, when the exhaust gas contains a specific photoresist such as polymethyl methacrylate (PMMA), it is generally very difficult to clean it completely in the cleaning process, and the small amount of photoresist remaining in the etching exhaust gas Combustion treatment should not be adopted for it (because it forms dioxins or oxazoles harmful substances). Therefore, other physical methods can only be adopted. At present, the oxidative combustion method is only applied to the treatment of some chemical vapor deposition (CVD) exhaust gases.

The adsorption method is a method for realizing selective separation and purification by the physical or chemical adsorption force between the components of the etching exhaust gas and the selected specific adsorbent. Commonly used aluminum oxide, activated carbon or molecular sieves have a significant adsorption effect on HF, HCl, _H2O , _SiF4 , _SiH4 , _CO2 and VOC with strong polarity, but the adsorption force is strong. Therefore, regeneration of the adsorbent is considerably difficult, and there are problems such as a short service life and an increase in cost. Also, it should be noted that the adsorbent for adsorbing HF is special. Many of such adsorbents use a basic metal fluoride, and the metal fluoride and HF chemically react at a low temperature to selectively perform chemisorption to form a metal fluoride-HF complex. Then, the desorption of HF from the adsorbent is realized by further performing the decomposition reaction of the complex at a high temperature. Realized. In many cases where such a chemisorption method is employed _, chlorofluoroalkanes (CFCs), hydrogen-containing chlorofluoroalkanes (HCFCs), hydrogen-containing fluoroalkanes (HFCs), sulfuryl fluoride ( _SO2F2 ), etc. The reaction mixture gas produced by the reaction has favorable selective adsorption, separation and recovery effects on HF, but the loss rate of the adsorbent is large. For etching exhaust gas containing water or _SiF4 or HCl foreign matter components, a chemical reaction or co-adsorption phenomenon also occurs between the adsorbent and foreign matter components such as water, so that the adsorbent becomes powdery or supersaturated and adsorbed. and cannot be effectively treated and cleaned. In addition, using a metal getter or a membrane separation system for selective adsorption is effective in desorbing some foreign matter, but the effect on the etching exhaust gas is not significant and the cost is high. In addition, one of the most serious problems of the adsorption method is that although this method is suitable for situations where the concentration of adsorbate (foreign matter) components in the etching exhaust gas is low, for high concentrations of foreign matter components, the adsorption capacity is often This limitation results in an increased adsorbent dosage, a corresponding increase in operating costs, and poor desorption efficiency.

Plasma purification is a currently prevalent treatment method, particularly for fluorinated waste gases including HF-containing exhaust gases, including etching exhaust gases and exhaust gases for the preparation of hydrogen fluoride. Plasma purification is to reinforce decomposition (destruction) of exhaust gas by plasma and directly convert harmful components. Such conversion is completed in a high density plasma region, which is obtained by glow discharge or other forms of discharge. A large amount of active particles are present in the plasma, and these particles can destroy toxic and persistent substances in the etching exhaust gas. This method, combined with plasma etching, is said to be a very promising exhaust gas treatment method. For example, pulsed corona plasma chemical treatment (PPCP) is an excellent treatment for oxynitrides ( _NOx ), sulfur dioxide ( _SO2 ), mercury (Hg) vapors and volatile organics (VOCs). have an effect. The desorption of _NOx and _SO2 occurs when the strong radicals generated by the pulsed corona undergo oxidation reactions with them, converting them to sulfates and nitrates in the presence of additives (e.g. ammonia ( _NH3 ) and _H2O ). The desorption of VOCs is that the high-energy electrons produced by the pulsed corona excite it, decompose it and ionize it, finally producing CO2 and CO, which are simple in structure _. . Hydrogen or hydrogen-containing compounds such as H ₂ , NH ₃ or methane (CH ₄ ) are added to the fluorinated exhaust gas to decompose components such as fluorides that are difficult to dissolve or decompose with water under plasma conditions. The resulting hydrogen ions (H+) form HF and HCl together with fluorine ions (F−) or chlorine ions (Cl+), and are washed with water to purify the fluorinated exhaust gas. Plasma, however, is only suitable for small-scale exhaust gas treatment because its treatment effect is not remarkable for etching exhaust gas with a high content of HF, HCl, etc., and it is expensive.

The conventional etching exhaust gas treatment methods described above all aim to detoxify toxic and harmful components and to make the exhaust gas meet the emission standards. Or H ₂ and the like cannot be recovered and used at all.

The object of the present invention is through FTrPSA (Full Temperature Range Pressure Swing Adsorption) which obtains high purity HF, HCl or _H2 from HF/HCl/ _H2 containing dry etch exhaust gas and recycles it back into the etching process. Another object of the present invention is to provide a method for separating, recovering, recycling and reusing etching exhaust gas containing HF/HCl.

Full temperature range pressure swing adsorption (Full Temperature Range-Pressure Swing Adsorption, hereinafter abbreviated as FTrPSA) is a method that can be combined with various separation technologies based on pressure swing adsorption (PSA). The absorption, adsorption, rectification, and physicochemical properties of each component (HF/HCl is the active component and the rest is the foreign component) in different pressures and temperatures. The two-stage intermediate temperature pressure swing adsorption process is mainly adopted, and this process is combined with spray absorption, HF rectification/HCl purification (rectification) and condensation, so that the adsorption and desorption in the intermediate temperature pressure swing adsorption process are matched and balanced. By separating and purifying HF/HCl by cyclic operation of adsorption and desorption, HF/HCl can be recovered and returned to the etching process for cyclic use.

The technical solution adopted in the present invention is the method of separation, recovery and recycling of HF/HCl-containing etching exhaust gas by FTrPSA, and the source gas is generated in the dry etching process of silicon or silicon carbide-based wafer chips. derived from the exhaust gas, mainly inert carrier gas (hydrogen gas (H ₂ )), active ingredients hydrogen fluoride (HF) and hydrogen chloride (HCl), and a small amount of water (H ₂ O), tetrafluoride silicon dioxide (SiF ₄ ), silicon tetrachloride (SiCl ₄ ), silane (SiH ₄ ), methane (CH ₄ ), carbon monoxide (CO), carbon dioxide (CO ₂ ) and traces of volatile organics ( VOC), metal ions (Me+), fine solids and aerosol particles (SS), some high fluorine silane acid/high chlorine silane foreign matter components, etc., the temperature is normal temperature, the pressure is normal pressure or micro-positive pressure.

The method for separating, collecting, recycling, and reusing the HF/HCl-containing etching exhaust gas by the FTrPSA includes:
(1) The temperature of the raw material gas is controlled to be normal temperature, the pressure is controlled to be 0.2 to 0.3 MPa, and includes a dust remover, a particle removal filter, a soot removal collector, and an activated carbon adsorber. It is fed into the pretreatment unit to desorb dust, particles, soot, VOC, high fluorine silane/acid and high chlorine silane in order, and the purified raw material gas formed through pretreatment is before entering the chlorosilane/HCl spray absorption process. a processing step;
(2) A spray absorption tower using a mixed liquid of chlorosilane and HCl as an absorbent is adopted as a reactor, and the purified raw material gas from the pretreatment process is heat-exchanged up to 50 to 80° C. and then introduced from the bottom of the spray absorption tower. back mass transfer exchange with the absorbent at the bottom of the spray absorption tower, the chlorosilane/HCl-enriched absorbent exits from the bottom of the absorption tower, enters the subsequent multi-stage evaporation-compression-condensation process, and simultaneously exits from the bottom of the tower. A small amount of residual particles, high-chlorine silane, high-fluorine silane/acid and other foreign matter are sent out for environmental protection treatment, and the non-condensable gas 1 enriched with HF and low boiling point components flows out from the top of the spray absorption tower, which is a chlorosilane/HCl spray absorption step entering a medium temperature pressure swing adsorption step;
(3) comprising a two-stage pressure swing adsorption process, wherein each stage of the pressure swing adsorption process comprises two or more adsorption towers, at least one adsorption tower being in the adsorption step and the remaining adsorption towers being in the desorption step; , the non-condensable gas 1 from the chlorosilane/HCl spray absorption process is introduced from the bottom of the first-stage PSA (1#PSA) adsorption tower, the operating pressure of 1#PSA is 0.2-0.3MPa, and the operating temperature is is 50-80 ° C, the non-adsorbed phase gas flowing out from the top of the adsorption tower in the adsorption step is crude HF gas, and the non-condensed gas 2 formed through condensation is subjected to microfiltration and absorption by deionized water. After performing the above, an aqueous HF solution with a concentration of 40% is obtained and sent out, and the non-condensable gas 3 formed through water absorption is a hydrogen-rich gas, which is sent out and used as fuel gas, or pressure swing It is used as the feed gas for hydrogen purification by adsorption, and the crude HF liquid formed through condensation is subjected to microfiltration before entering the next process, the HF rectification process, from the bottom of the 1#PSA adsorption tower in the desorption step. The outflowing desorption gas is subjected to pressure increase and heat exchange, and then enters from the bottom of the second stage PSA (2#PSA) adsorption tower, and the operating pressure of the 2#PSA adsorption tower is 0.2-0.3MPa. , the operating temperature is 50-80° C., and the non-adsorbed phase intermediate gas exiting the top of the 2#PSA adsorption tower in the adsorption step is mixed with 1 of the non-condensable gas from the chlorosilane/HCl spray absorption step before returning. into the 1#PSA adsorption tower to recover the active ingredients HF and HCl, and the desorption gas flowing out from the bottom of the 2#PSA adsorption tower is the enriched gas, which is returned to the chlorosilane/HCl spray absorption process, and further a medium temperature pressure swing adsorption step for recovering the active ingredient;
(4) including a rectification column consisting of two stages of rectification, wherein the purified HF liquid obtained after the crude HF gas from the intermediate temperature pressure swing adsorption step is condensed into the rectification column in the HF rectification step; , the purified HF liquid enters from the top of the lower rectification column or the bottom of the upper rectification column, and the light component foreign matter gas distilled at the top of the upper rectification column is returned to the subsequent exhaust gas absorption step, and the upper rectification The non-condensable gas 4 formed by the condensation of the distillate at the bottom of the column or the top of the lower rectification column is anhydrous HF (AHF) gas with a purity of 99.99% or more, which is directly converted into an electronic grade The HF product gas is recycled back to the dry etching process, and the liquid formed through condensation is used as the reflux of the upper or lower rectification, and contains a small amount of foreign matter components of the heavy components distilled at the bottom of the lower rectification. Part of the non-condensable gas 5 formed by condensation of the bottom fluid is sent to the multi-stage evaporation, compression and condensation process, and the remaining part is sent to the exhaust gas absorption process to absorb the liquid formed by condensation. HF rectification step recycled as agent back to chlorosilane/HCl spray absorption step;
(5) Allowing the absorbent from the chlorosilane/HCl spray absorption step to enter a multi-stage evaporation step and then to a condenser from which crude HCl gas in the vapor phase is obtained for heavy components from the HF rectification step. is mixed with the uncondensable gas 5 obtained after condensing the bottoms fluid of , and the crude HCl liquid formed through condensation is sent to the HCl purification step, and the crude chlorosilane liquid flows out from the condenser, which is used in the subsequent The non-condensable gas 6 flowing out from the condenser is heat-exchanged and then returned to the intermediate temperature pressure swing adsorption step, and the active ingredients HF and HCl are recovered. process and
(6) including an HCl rectification column and a vacuum rectification column, the operating pressure of the HCl rectification column is 0.3-0.6 MPa, the operating temperature is 50-80° C., and the operating pressure of the vacuum rectification column; is −0.08 to −0.1 MPa, the operating temperature is 60 to 120° C., and part of the HCl product gas exiting the top of the HCl rectification column with a purity greater than 99.99% is subjected to a dry etching process. The remaining part is liquefied and then recycled as an absorbent in the chlorosilane/HCl spray absorption process, and the bottom effluent of the HCl rectification column is introduced into the vacuum rectification column for vacuum purification. The overhead gas flowing out from the top of the distillation column is the non-condensable gas 7, part of which is sent to the subsequent exhaust gas absorption process, the other part is returned to the intermediate temperature pressure swing adsorption process, and is returned to the bottom of the vacuum rectification column. a portion of the heavy components flowing out from the HCI is returned to the multi-stage evaporation-compression-condensation step and the other portion is sent to the weak-cold rectification step in chlorosilane;
(7) including a rectification column, introducing the crude chlorosilane liquid from the multi-stage evaporation, compression and condensation process, and/or the heavy component fluid at the bottom of the vacuum column from the HCl purification process, with an operating temperature of -35 to 10°C; The operating pressure is 0.6 to 2.0 MPa, and the noncondensable gas 8 flowing out from the top of the rectification column is heat-exchanged, returned to the intermediate temperature pressure swing adsorption step, and discharged from the bottom of the rectification column. Part of the effluent chlorosilane liquid is mixed with HCl to form a mixed liquid, and recycled back to the chlorosilane/HCl spray absorption process as an absorbent, and another part is mixed with sulfuric acid to absorb the exhaust gas absorption process. A weak cold rectification step in chlorosilane used as an agent,
(8) Adopting as a reactor the exhaust gas absorption tower with the mixed liquid of the chlorosilane liquid from the weak cold rectification process in chlorosilane and fresh sulfuric acid as the absorbent, and distilling at the top of the upper rectification tower from the HF rectification process; The foreign matter gas of the light components thus obtained was mixed with the non-condensable gas 5 formed through condensation of the heavy components flowing out from the bottom of the lower rectification column from the HF rectification process and the non-condensable gas 7 from the HCl refining process. After that, it is introduced into the exhaust gas absorption tower, and the fluorosilicic acid solution formed at the bottom of the absorption tower is sent out as a raw material, circulated and used as a raw material liquid in the production process of preparing AHF by the fluorosilicic acid removal method, and is discharged from the top of the absorption tower. and an exhaust gas absorption step for directly discharging the outflowing non-condensable gas 9 as exhaust gas.

In addition, when the content of HCl in the feed gas is less than 1%, the purified feed gas is allowed to directly enter the intermediate temperature pressure swing adsorption step, and the crude HF gas exiting from the top of the 1#PSA column undergoes condensation to form impurities. After the condensed gas 2 is subjected to microfiltration and absorption with deionized water, an HF aqueous solution with a concentration of 40% is obtained and sent outside, and the non-condensable gas 3 formed through water absorption is a hydrogen-rich gas, It is delivered and used as a fuel gas or as a feed gas for hydrogen purification by pressure swing adsorption, and the crude HF liquid formed through condensation is microfiltered before entering the HF rectification step and undergoing a desorption step. The desorbed gas flowing out from the bottom of the 1#PSA adsorption tower is pressurized and heat exchanged, and then enters from the bottom of the second stage PSA (2#PSA) adsorption tower, and the 2#PSA adsorption tower in the adsorption step. The intermediate gas of the non-adsorbed phase flowing out from the top is directly returned to enter the 1#PSA adsorption tower to recover the active ingredients, and the desorbed gas flowing out from the bottom of the 2#PSA adsorption tower is the enriched gas, which is newly added. The non-condensable gas 1 formed after passing through the newly added condenser is further mixed with the crude HF gas in the intermediate temperature pressure swing adsorption process to recover the active ingredient HF, and the liquid formed after the newly added condenser is used in the HCl purification process. to recover HCl, treat the heavy components discharged from the HCl refining process, and then directly discharge it, chlorosilane/HCl spray absorption, multi-stage evaporation, compression, condensation and medium-low cold chlorosilane rectification process. Omit.

Furthermore, when the concentration of HF in the raw material gas is lower than the concentration of HCl, the purified raw material gas from the pretreatment process is heat-exchanged to 80 to 160° C. before entering the chlorosilane/HCl spray absorption process, and the top of the spray absorption tower is The non-condensable gas 2 formed by the condensation of the non-condensable gas 1 flowing out of is further entered into the intermediate temperature pressure swing adsorption process consisting of two stages of PSA, and the condensed liquid formed through condensation directly enters the HCl purification process, The absorbent flowing out from the bottom of the spray absorption tower is subjected to multiple stages of evaporation, compression and condensation.

Furthermore, when the concentration of HF in the raw material gas is lower than the concentration of HCl, the purified raw material gas from the pretreatment process is heat-exchanged to 80 to 160° C. before entering the chlorosilane/HCl spray absorption process, and the top of the spray absorption tower is The noncondensable gas 2 formed by the condensation of the noncondensable gas 1 flowing out of the is further entered into the intermediate temperature pressure swing adsorption process consisting of two stages of PSA, and the noncondensable gas 2 is transferred to the first stage PSA (1#PSA) adsorption tower. , the operating pressure of 1#PSA is 0.2-0.3 MPa, the operating temperature is 50-80 ° C., and the non-adsorbed phase gas flowing out from the top of the adsorption tower in the adsorption step is intermediate gas, which is introduced into the bottom of the second stage (2#PSA) adsorption tower, and the non-adsorbed phase gas flowing out from the top of the adsorption tower in the adsorption step is crude HF gas, formed through condensation The uncondensable gas 3 is subjected to microfiltration and absorption with deionized water to obtain an HF aqueous solution with a concentration of 40% and is sent outside, and the noncondensable gas 4 formed through water absorption is a hydrogen-rich gas. , send it out and use it as a fuel gas or as a feed gas for hydrogen purification by pressure swing adsorption, and the crude HF liquid formed through condensation is microfiltered before entering the HF rectification process, 1# in the desorption step The desorbed gas from the bottom of the PSA adsorption tower and the concentrated gas from the bottom of the 2#PSA adsorption tower are respectively returned to the chlorosilane/HCl spray absorption process to further recover the active ingredients, and the non-condensable gas 1 is formed through condensation. The resulting condensed liquid directly enters the HCl purification process, and the absorbent exiting from the bottom of the spray absorption tower enters the multi-stage evaporation-compression-condensation process.

Further, if the total concentration of HF and HCl in the feed gas does not exceed 3%, the purified feed gas obtained by subjecting the feed gas to a pretreatment step is directly subjected to a medium temperature pressure swing adsorption step comprising a single PSA. A single stage PSA consists of two or more adsorption towers, one adsorption tower is in the adsorption step, and the remaining adsorption towers contain different stages of pressure reduction, reverse venting or evacuation or pressure rise or final gas filling. In the desorption step, the operation pressure of the adsorption tower is 0.2-0.3 MPa, the operation temperature is 70-90 ℃, the purified raw gas is introduced from the bottom of the PSA adsorption tower, and the adsorption tower in the adsorption step is The non-adsorbed phase gas exiting the top of the adsorption tower is the adsorption waste gas, which is used as fuel gas or as feed gas for hydrogen purification by pressure swing adsorption, and the enriched gas exiting the bottom of the adsorption tower in the desorption step is The non-condensable gas 1 formed through condensation is mixed with the purified feed gas and returned to the intermediate temperature pressure swing adsorption step for further recovery of active ingredients, and the condensed liquid formed through condensation is further entered into the HF rectification step to The non-condensable gas 2 discharged from the rectification process is sent to the exhaust gas absorption process for treatment, the HF product gas discharged from the HF rectification process is returned to the dry etching process for recycling, and discharged from the bottom of the HF rectification tower. By directly entering the HCl purification process, thus obtaining the HCl product gas, and recycling it back to the dry etching process, the chlorosilane/HCl spray absorption, multi-stage evaporation-compression-condensation, medium A weakly cooled chlorosilane rectification step can be omitted, and the operating conditions are also suitable for separating and recovering and reusing low-concentration HF/HCl-containing acidic exhaust gases after treating the etching exhaust gases by the conventional water washing absorption process.

Furthermore, when the concentration of HF/HCl in the raw material gas exceeds 20%, the uncondensed gas 1 formed by condensing the purified raw material gas that has undergone the pretreatment step is washed with water to remove a small amount of residual acidic components. The noncondensable gas 2 formed by desorption, dilute acid is produced and sent to the outside, washed with water, is used as a fuel gas or a raw material gas for hydrogen purification by pressure swing adsorption, and is condensed to form a condensate. is introduced into the HF rectification process, the non-condensable gas 3 flowing out of the HF rectification process is processed by entering the exhaust gas absorption process, and the HF product gas flowing out of the HF rectification process is returned to the dry etching process and recycled. Then, the heavy component fluid exiting from the bottom of the HF rectification column directly enters the HCl purification step, thus obtaining the HCl product gas, which is recycled back to the dry etching process, chlorosilane/HCl spray absorption, Eliminating multi-stage evaporation/compression/condensation, medium-weak cold chlorosilane rectification and medium-temperature pressure swing adsorption processes, this operating condition is also suitable for separating and recovering and reusing high-concentration HF/HCl-containing flue gas produced after plasma cleaning. .

Further, in the intermediate temperature pressure swing adsorption step, the raw material gas for hydrogen purification by pressure swing adsorption is the non-condensable gas or adsorption waste gas produced after washing with water, and the non-condensable gas or adsorption waste gas is first introduced into the drying tower, Hydrogen-enriched purifying methane by desorbing acidic components containing water and a small amount of fluorine and chlorine, followed by an adsorption purification stage, desorbing foreign substances including silane, phosphorane, and metal ions. - obtain hydrogen gas, pressurize to 1.0-3.0 MPa, then heat-exchange to normal temperature, enter into a hydrogen purification process by pressure swing adsorption consisting of four or more adsorption towers, so that the adsorption towers From the top, ultra-pure hydrogen with a purity of 99.99-99.999% flows out and enters a hydrogen gas purification process consisting of a palladium membrane or metal getter to produce a _H2 product gas that meets electronic grade hydrogen gas standards. The desorbed gas flowing out from the bottom of the adsorption tower is the methane-rich gas, which is directly used as fuel gas.

The beneficial effects of the present invention are as follows.
(1) According to the present invention, it is possible to separate and recover HF and HCl from the HF/HCl-containing dry etching exhaust gas and return them to the etching process for recycling. The environmental protection treatment cost of flue gas is greatly reduced, and the problem that the conventional technology only emits if it reaches the standard and cannot realize the comprehensive utilization of flue gas is solved, filling the void in this technical field.
(2) In the present invention, adsorption/absorption/rectification/condensation coefficients and physicochemical properties of each component in the source gas (HF/HCl is the active component and the rest is the foreign matter component) at different pressures and temperatures , mainly adopting the two-stage intermediate temperature pressure swing adsorption process, and combining this process with chlorosilane spray absorption, HF rectification, HCl purification (rectification), chlorosilane rectification and evaporation/compression/condensation. , the adsorption and desorption in the intermediate temperature pressure swing adsorption process are easily matched and balanced, and by performing separation and purification through the cyclic operation of adsorption and desorption, HF / HCl is separated from other foreign matter components and purified. It is realized to return to the dry etching process and recycle.
(3) In the conventional chemisorption method, the HF and the adsorbent cause a chemical reaction (chelate) at low temperature to adsorb, and decompose at high temperature to desorb, resulting in frequent cycles of adsorption and desorption. The loss rate of the adsorbent increases during the operation process, and the adsorbent undergoes chemical reactions with foreign substances such as water, so the adsorbent becomes pulverized and deactivated, making it impossible to effectively perform adsorption separation. Overcoming the problem, taking advantage of the characteristics of both HF and HCl that are highly polar and easy to adsorb but difficult to By adjusting the cyclic operation of adsorption and desorption, such a phenomenon can be avoided and the service life of the adsorbent can be extended.
(4) In the case of different raw material gases, the present invention can realize the recovery and reuse of HF/HCl by effectively simplifying the flow. By combining the method and the present invention, the etching exhaust gas can be treated, the HF/HCl can be effectively recovered, and the HF/HCl can be recycled back to the etching process or dry cleaning process, and the defects that cannot be recovered by the conventional treatment method can be solved. and reach emission standards as well.
(5) The present invention can recover and recycle HF/HCl from etching exhaust gas, and at the same time obtain valuable electronic grade _H2 products by adding PSA to purify hydrogen. and can be recycled back to the dry etching process, or can be used as a hydrogen source for other semiconductor processes, while the process carrier gas is argon gas or nitrogen gas or hydrogen gas. If it is a mixed gas with, the PSA can be adjusted for hydrogen purification or argon purification or nitrogen purification, or low temperature adsorption can be added to obtain electronic grade argon gas, nitrogen gas, etc. products.

It is a flow chart of Example 1 of the present invention. It is a flowchart of Example 2 of this invention. It is a flow chart of Example 3 of the present invention. It is a flow chart of Example 4 of the present invention. It is a flow chart of Example 5 of the present invention. It is a flowchart of Example 6 of this invention. It is a flowchart of Example 7 of this invention.

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail. The specific examples described herein are only for the purpose of interpreting the invention and not for limiting the embodiments of the invention, i.e. the examples described It is to be understood that this is only some, but not all, embodiments of the invention.

Example 1
As shown in FIG. 1, in the separation, recovery, recycling and recycling method of HF/HCl-containing etching exhaust gas by FTrPSA, the raw material gas is derived from the exhaust gas generated during the dry etching process of silicon-based wafer chips, and is mainly inert. 83% (v/v) hydrogen gas (H ₂ ) as a carrier gas, 9% hydrogen fluoride (HF) and 5% hydrogen chloride (HCl) as active ingredients, and a small amount of water (H ₂ O). silicon fluoride ( _SiF4 ), silicon tetrachloride ( _SiCl4 ), silane ( _SiH4 ), methane ( _CH4 ), carbon monoxide (CO), carbon dioxide ( _CO2 ), and trace or trace amounts of volatile It contains organic substances (VOC), metal ions (Me+), fine solids and aerosol particles (SS), some high fluorine silane acid/high chlorine silane foreign matter components, and is normal temperature and pressure.

The specific implementation process is
(1) After increasing the pressure of the raw material gas, it is sent to a pretreatment unit consisting of a dust remover, a particle removal filter, a soot removal collector, and an activated carbon adsorber, and the pressure is 0.2 to 0.3 MPa and normal temperature. Dust, particles (SS), soot, VOC, high-fluorine silane/acid and high-chlorine silane are sequentially desorbed under the operating conditions of , and the purified raw material gas thus formed is subjected to the next step, the chlorosilane/HCl spray absorption step. A pretreatment step for entering the
(2) After heat-exchanging the purified raw material gas from the pretreatment process to 50 to 80° C., it is introduced into the spray absorption tower from the bottom, and a mixed liquid of chlorosilane and HCl (1:1 to 1.4) is used as an absorbent. is used, spraying downward from the top of the spray absorption tower to cause reverse mass transfer exchange with the purified raw gas, and the chlorosilane/HCl-enriched absorption liquid flows out from the bottom of the spray absorption tower, which is used for the subsequent multi-stage evaporation. Compressing and condensing process, and at the same time sending out a small amount of residual particles, high-chlorine silane, high-fluorine silane/acid and other foreign matter from the bottom of the tower for environmental protection treatment, and HF and low boiling point components from the top of the spray absorption tower. a chlorosilane/HCl spray absorption step in which the non-condensible gas 1 enriched in
(3) The noncondensable gas 1 from the chlorosilane/HCl spray absorption step is introduced into a medium temperature pressure swing adsorption step consisting of two stages of pressure swing adsorption (PSA), and the first and second stages of pressure swing adsorption (1#PSA) , 2#PSA) each consist of three adsorption towers, one of which is in the adsorption step, and the remaining two adsorption towers are in different stages of depressurization/back-venting or evacuation, pressurization or final gassing. in the desorption step including, let the noncondensable gas 1 enter from the bottom of the 1#PSA adsorption tower, the operating pressure of 1#PSA is 0.2-0.3MPa, the operating temperature is 50-80 ℃, The non-adsorbed phase gas flowing out from the top of the adsorption tower in the adsorption step is crude HF gas, and the non-condensable gas 2 formed through condensation is subjected to microfiltration and absorption with deionized water, and the concentration is 40%. HF aqueous solution is obtained and sent out, and the non-condensable gas 3 formed through water absorption is hydrogen-rich gas, which is sent out and used as fuel gas, while the crude HF liquid formed through condensation is finely filtered (less than 10 micrometers), the next step, the HF rectification step, was introduced, and the desorption gas flowing out from the bottom of the 1#PSA adsorption tower in the desorption step was pressurized to 0.2 to 0.3 MPa. After entering from the bottom of the 2#PSA adsorption tower, the operating pressure of the 2#PSA adsorption tower is 0.2-0.3MPa, the operating temperature is 50-80 ℃, and the 2#PSA adsorption tower is in the adsorption step. The intermediate gas of the non-adsorbed phase flowing out from the top of the is mixed with the non-condensable gas 1 from the chlorosilane/HCl spray absorption step and returned to the 1# PSA adsorption tower, further recovering the active ingredients HF and HCl, and 2 # A medium temperature pressure swing adsorption step in which the desorbed gas flowing out from the bottom of the PSA adsorption tower is a concentrated gas, which is returned to the chlorosilane/HCl spray absorption step to further recover the active ingredients;
(4) The purified HF liquid formed by the condensation of the crude HF gas from the intermediate temperature pressure swing adsorption step is introduced into the rectification column of the HF rectification step, and the rectification column of this step consists of upper and lower two-stage rectification. , the purified HF liquid enters the top of the lower rectification, the foreign gas of light components distilled at the top of the upper rectification column is treated by entering the subsequent exhaust gas absorption process, and the bottom distillate of the upper rectification is The non-condensable gas 4 formed by the condensation of the effluent is anhydrous HF (AHF) gas with a purity of 99.99% or more, and is directly recycled back to the dry etching process as an electronic grade HF product gas, The liquid formed through condensation is used as the reflux of the upper rectification, and the bottoms fluid containing a small amount of heavy components and foreign matter components distilled at the bottom of the lower rectification is condensed to form non-condensable gas 5. 70% is sent to the next step, the multi-stage evaporation-compression-condensation process, 30% is sent to the subsequent exhaust gas absorption process, and the liquid formed through condensation is returned to the chlorosilane/HCl spray absorption process as an absorbent. an HF rectification step in which the circulating two-stage rectification column has an operating temperature of 18 to 100° C. and an operating pressure of 0.03 to 0.2 MPa;
(5) Allowing the absorbent from the chlorosilane/HCl spray absorption step to enter a multi-stage evaporation step and then to a condenser from which crude HCl gas in the vapor phase is obtained for heavy components from the HF rectification step. is mixed with the uncondensable gas 5 obtained after the bottoms fluid is condensed, and the crude HCl liquid formed through condensation is sent to the next HCl purification step, and the crude chlorosilane liquid flows out of the condenser. Then, it is sent to the subsequent weak-cold rectification step in chlorosilane, where the non-condensable gas 6 flowing out from the condenser is heat-exchanged, and then returned to the intermediate temperature pressure swing adsorption step, and the active ingredients HF and HCl are recovered. Evaporation/compression/condensation process,
(6) The crude HCl liquid from the multi-stage evaporation/compression/condensation process is introduced into the HCl purification process consisting of the HCl rectification column and the vacuum rectification column, and the operating pressure of the HCl rectification column is 0.3-0.6 MPa. , the operating temperature is 50 ~ 80 ° C, the operating pressure of the vacuum rectification column is -0.08 ~ -0.1 MPa, the operating temperature is 60 ~ 120 ° C, and the HCl rectification column is discharged from the top Part of the HCl product gas with a purity greater than 99.99% is recycled back to the dry etching process, part is liquefied and then recycled as an absorbent in the chlorosilane/HCl spray absorption step, and HCl rectification. The effluent from the bottom of the column enters the vacuum rectification column, part of the overhead gas (non-condensable gas 7) exiting the top of the vacuum rectification column enters the subsequent exhaust gas absorption step, and part of the Returning to the pressure swing adsorption process, part of the heavy components flowing out from the bottom of the vacuum rectification column is returned to the multi-stage evaporation/compression/condensation process, and part of it is sent to the next process, the weak cold rectification process in chlorosilane. a HCl purification step that allows
(7) entering after mixing the crude chlorosilane liquid from the multi-stage evaporation/compression/condensation process and/or the vacuum column bottom heavy component fluid from the HCl purification process, the operating temperature being -35 to 10°C; The operating pressure is 0.6 to 2.0 MPa, and the noncondensable gas 8 flowing out from the top of the rectifying column is heat-exchanged and then returned to the intermediate temperature pressure swing adsorption step, and the chlorosilane flowing out from the bottom of the rectifying column. A part of the liquid is mixed with HCl in an appropriate ratio (1:1-1.4) to form a mixed liquid, which is recycled back to the chlorosilane/HCl spray absorption process as an absorbent, and a part is mixed with sulfuric acid. A weak-cold rectification step in chlorosilane used as an absorbent in the exhaust gas absorption step, which is the next step,
(8) The foreign gas of the light component distilled at the top of the upper rectification column from the HF rectification process and the heavy component flowing out from the bottom of the lower rectification column from the HF rectification process are formed through condensation. After mixing a part of the non-condensable gas 5 and a part of the non-condensable gas 7 from the HCl refining process, exhaust gas absorption with a mixture of chlorosilane liquid from the weak cold rectification process in chlorosilane and fresh sulfuric acid as an absorbent. It enters the tower, forms a fluorosilicic acid solution at the bottom of the absorption tower, is sent out as a raw material, and is recycled as a raw material liquid in the production process of preparing AHF by the fluorosilicic acid removal method, and the waste flowing out from the top of the absorption tower. and an exhaust gas absorption step for directly discharging the condensed gas 9 as exhaust gas.

Example 2
As shown in FIG. 2, based on Example 1, when the concentration of HCl in the feed gas is less than 1% and the concentration of HF is increased to about 13%, the purified feed gas is directly entered into the intermediate temperature pressure swing adsorption process. Then, the non-condensable gas 2 formed by the condensation of the crude HF gas flowing out from the top of the 1#PSA column is subjected to microfiltration and absorption with deionized water to obtain an HF aqueous solution with a concentration of 40%, which is discharged to the outside. The non-condensable gas 3 formed through pumping and water absorption is the hydrogen-rich gas, which is pumped and used as fuel gas, while the crude HF liquid formed through condensation is microfiltered before entering the HF rectification process. The desorption gas flowing out from the bottom of the 1#PSA adsorption tower in the desorption step is pressurized to 0.2 ~ 0.3 MPa, and then entered from the bottom of the 2#PSA adsorption tower to enter the 2#PSA in the adsorption step. The intermediate gas of the non-adsorbed phase flowing out from the top of the adsorption tower is directly returned to enter the 1#PSA adsorption tower to recover the active ingredient, and the desorption gas flowing out from the bottom of the 2#PSA adsorption tower is the enriched gas. , the non-condensable gas 1 formed after passing through the newly added condenser is further mixed with the crude HF gas in the intermediate temperature pressure swing adsorption process to recover the active ingredient HF, and the liquid formed after the newly added condenser is Chlorosilane/HCl spray absorption, multi-stage evaporation/compression/condensation and medium-weak cold chlorosilane Eliminates the rectification step.

Example 3
As shown in FIG. 3, based on Example 1, when the concentration of HF (5%) in the source gas is less than the concentration of HCl (9%), the purified source gas from the pretreatment process is heated to 80 to 160 ° C. After heat exchange, it is introduced into the chlorosilane/HCl spray absorption process, and the noncondensable gas 2 formed through condensation of the noncondensable gas 1 flowing out from the top of the spray absorption tower is further passed to the intermediate temperature pressure swing adsorption process comprising two stages of PSA. The condensed liquid formed through condensation directly enters the HCl purification process, and the absorbent exiting from the bottom of the spray absorption tower enters the multi-stage evaporation-compression-condensation process.

Example 4
As shown in FIG. 4, based on Examples 1 and 3, when the concentration of HF in the source gas is 5% and the concentration of HCl is 9%, the purified source gas from the pretreatment step is changed to 80%. After heat exchange up to ~160°C, the chlorosilane/HCl spray absorption step is entered, and the noncondensable gas 2 formed through condensation of the noncondensible gas 1 flowing out from the top of the spray absorption tower is further converted into a medium temperature pressure gas comprising two stages of PSA. Entering the swing adsorption process, the noncondensable gas 2 is cooled to 50-80 ° C. and then enters from the bottom of the 1#PSA adsorption tower, the operating pressure of 1#PSA is 0.2-0.3MPa, and the operating temperature is is 50-80 ℃, the non-adsorbed phase gas flowing out from the top of the adsorption tower in the adsorption step is the intermediate gas, let it enter the bottom of the 2#PSA adsorption tower, and the top of the adsorption tower in the adsorption step The non-adsorbed phase gas flowing out of is crude HF gas, and the non-condensable gas 3 formed through condensation is subjected to microfiltration and absorption with deionized water to obtain an HF aqueous solution with a concentration of 40%, which is discharged to the outside. The non-condensable gas 4 formed through pumping and water absorption is the hydrogen-rich gas, which is pumped and used as fuel gas, while the crude HF liquid formed through condensation is microfiltered prior to the HF rectification process. the desorbed gas flowing out from the bottom of the 1#PSA adsorption tower in the desorption step and the concentrated gas flowing out of the bottom of the 2#PSA adsorption tower are respectively returned to the chlorosilane/HCl spray absorption process to further recover the effective ingredients; The condensed liquid formed by the condensation of the non-condensable gas 1 directly enters the HCl purification process, and the absorbent flowing out from the bottom of the spray absorption tower enters the multi-stage evaporation-compression-condensation process.

Example 5
As shown in FIG. 5, based on Example 1, when the total concentration of HF and HCl in the source gas does not exceed 3% and the content of _H2 exceeds 90%, the pretreatment process The purified feed gas obtained through is directly entered into a single-stage PSA intermediate pressure swing adsorption process, the single-stage PSA is composed of four adsorption towers, one adsorption tower is in the adsorption step, and the remaining adsorption towers are in the desorption step including different stages of depressurization/reverse venting or evacuation, pressure increase or final gas filling, the operating pressure of the adsorption tower is 0.2-0.3 MPa, the operating temperature is 70-90° C., Purified raw gas enters from the bottom of the PSA adsorption tower, and the non-adsorbed phase gas that flows out from the top of the adsorption tower in the adsorption step is the adsorption waste gas, which is used as fuel gas for the adsorption tower in the desorption step. The non-condensable gas 1 formed through condensation of the enriched gas flowing out from the bottom is mixed with the purified feed gas and returned to the intermediate temperature pressure swing adsorption step for further recovery of active components, and the condensed liquid formed through condensation is further purified by HF. The non-condensable gas 2 flowing out of the HF rectification process is introduced into the distillation process and treated in the exhaust gas absorption process, the HF product gas flowing out of the HF rectification process is returned to the dry etching process and recycled, and the HF The heavy component fluid discharged from the bottom of the rectification column directly enters the HCl purification process, thus obtaining the HCl product gas, and recycling it back to the dry etching process, chlorosilane/HCl spray absorption, multi-stage evaporation and Eliminates compression/condensation and medium-low-cooling chlorosilane rectification processes. This operating situation is also suitable for separating and recovering and reusing low-concentration HF/HCl-containing acidic exhaust gas after treating the etching exhaust gas by the conventional water washing absorption method.

Example 6
As shown in FIG. 6, based on Example 1, when the HF/HCl concentration in the raw material gas is 30% and the hydrogen gas concentration is less than 70%, the purified raw material gas that has undergone the pretreatment process is condensed. The formed noncondensable gas 1 is washed with water to desorb a small amount of residual acidic components, a dilute acid is generated and sent out, and the noncondensable gas 2 formed after washing is used as fuel gas, The condensate formed through condensation is sent to the HF rectification process, the non-condensable gas 3 flowing out of the HF rectification process is treated by entering the exhaust gas absorption process, and the HF product gas flowing out of the HF rectification process is dry-processed. Recycled back to the etching process, the heavy component fluid exiting from the bottom of the HF rectification column directly enters the HCl purification step, thus obtaining the HCl product gas and recycled back to the dry etching process. This eliminates the chlorosilane/HCl spray absorption, multi-stage evaporation-compression-condensation, medium-low cold chlorosilane rectification and medium-temperature pressure swing adsorption steps. This operating situation is also suitable for separation and recovery recycling of high HF/HCl containing exhaust gases produced after plasma cleaning.

Example 7
As shown in FIG. 7, based on Examples 1 to 6, hydrogen purification by pressure swing adsorption using all the non-condensable gas or adsorption waste gas produced after water washing in the intermediate temperature pressure swing adsorption step as fuel gas. First, the non-condensable gas or adsorption waste gas is introduced into the drying tower, and the moisture and acidic components containing a small amount of fluorine and chlorine are desorbed, followed by adsorption purification. Enter the stage to desorb foreign matter including silane, phosphorane and metal ions to obtain hydrogen-enriched purified methane-hydrogen gas, pressurize to 2.6-3.0 MPa, and then heat exchange to normal temperature. Then, it is put into a hydrogen refining process by pressure swing adsorption consisting of five adsorption towers, ultrapure hydrogen with a purity of 99.99 to 99.999% flows out from the top of the adsorption tower, and it is hydrogen gas composed of metal getter. Enter the purification process to obtain _H2 product gas that meets electronic grade hydrogen gas standards, and recycle it back to the dry etching process, the desorption gas exiting the bottom of the adsorption tower is methane-rich gas, Use it as fuel gas.

Apparently, the embodiments described above are only some of the embodiments of the present invention, but not all of the embodiments. Based on the embodiment described in the present invention, all other embodiments obtained without creative work by those skilled in the art, or structural modifications made based on the suggestions of the present invention, are the same as the present invention. or have similar technical solutions, they are all within the protection scope of the present invention.

Claims (7)

(1) The temperature of the raw material gas is controlled to be normal temperature, the pressure is controlled to be 0.2 to 0.3 MPa, and includes a dust remover, a particle removal filter, a soot removal collector, and an activated carbon adsorber. It is fed into the pretreatment unit to desorb dust, particles, soot, VOC, high fluorine silane/acid and high chlorine silane in order, and the purified raw material gas formed through pretreatment is before entering the chlorosilane/HCl spray absorption process. a processing step;
(2) A spray absorption tower using a mixed liquid of chlorosilane and HCl as an absorbent is adopted as a reactor, and the purified raw material gas from the pretreatment process is heat-exchanged up to 50 to 80° C. and then introduced from the bottom of the spray absorption tower. back mass transfer exchange with the absorbent at the bottom of the spray absorption tower, the chlorosilane/HCl-enriched absorbent exits from the bottom of the absorption tower, enters the subsequent multi-stage evaporation-compression-condensation process, and simultaneously exits from the bottom of the tower. A small amount of residual particles, high-chlorine silane, high-fluorine silane/acid and other foreign matter are sent out for environmental protection treatment, and the non-condensable gas 1 enriched with HF and low boiling point components flows out from the top of the spray absorption tower, which is a chlorosilane/HCl spray absorption step entering a medium temperature pressure swing adsorption step;
(3) comprising a two-stage pressure swing adsorption process, wherein each stage of the pressure swing adsorption process comprises two or more adsorption towers, at least one adsorption tower being in the adsorption step and the remaining adsorption towers being in the desorption step; , the non-condensable gas 1 from the chlorosilane/HCl spray absorption process enters from the bottom of the first stage pressure swing adsorption 1#PSA adsorption tower, the operating pressure of 1#PSA is 0.2-0.3MPa, and the operating temperature is is 50-80 ° C, the non-adsorbed phase gas flowing out from the top of the adsorption tower in the adsorption step is crude HF gas, and the non-condensed gas 2 formed through condensation is subjected to microfiltration and absorption by deionized water. After performing the above, an aqueous HF solution with a concentration of 40% is obtained and sent out, and the non-condensable gas 3 formed through water absorption is a hydrogen-rich gas, which is sent out and used as fuel gas, or pressure swing adsorption The crude HF liquid formed through condensation is subjected to microfiltration before entering the HF rectification process, and is added to the desorption gas flowing out from the bottom of the 1#PSA adsorption tower in the desorption step. After pressure and heat exchange, the second pressure swing adsorption 2#PSA adsorption tower is introduced from the bottom. At 80° C., the non-adsorbed phase intermediate gas flowing out from the top of the 2#PSA adsorption tower in the adsorption step is mixed with 1 non-condensable gas from the chlorosilane/HCl spray absorption step and returned to the 1#PSA adsorption tower. to recover the active ingredients HF and HCl, and the desorption gas flowing out from the bottom of the 2#PSA adsorption tower is the enriched gas, which is returned to the chlorosilane/HCl spray absorption process to recover the active ingredients. a pressure swing adsorption step;
(4) including a rectification column consisting of two stages of rectification, wherein the purified HF liquid obtained after the crude HF gas from the intermediate temperature pressure swing adsorption step is condensed into the rectification column in the HF rectification step; , the purified HF liquid enters from the top of the lower rectification column or the bottom of the upper rectification column, and the light component foreign matter gas distilled at the top of the upper rectification column is returned to the subsequent exhaust gas absorption step, and the upper rectification The non-condensable gas 4 formed by condensation of the distillate at the bottom of the column or the top of the lower rectification column is anhydrous HF gas with a purity of not less than 99.99%, which is directly used as an electronic grade HF product gas. The liquid formed through condensation is used as the reflux of the upper or lower rectification, and the bottom of the column containing a small amount of foreign matter components of the heavy components distilled at the bottom of the lower rectification A part of the non-condensable gas 5 formed by the condensation of the material fluid is sent to the multi-stage evaporation/compression/condensation process, the other part is sent to the exhaust gas absorption process, and the liquid formed by the condensation is used as an absorbent for chlorosilane. a HF rectification step that is recycled back to the /HCl spray absorption step;
(5) Allowing the absorbent from the chlorosilane/HCl spray absorption step to enter a multi-stage evaporation step and then to a condenser from which crude HCl gas in the vapor phase is obtained for heavy components from the HF rectification step. is mixed with the uncondensable gas 5 obtained after condensing the bottoms fluid of , and the crude HCl liquid formed through condensation is sent to the HCl purification step, and the crude chlorosilane liquid flows out from the condenser, which is used in the subsequent The non-condensable gas 6 flowing out from the condenser is heat-exchanged and then returned to the intermediate temperature pressure swing adsorption step, and the active ingredients HF and HCl are recovered. process and
(6) including an HCl rectification column and a vacuum rectification column, the operating pressure of the HCl rectification column is 0.3-0.6 MPa, the operating temperature is 50-80° C., and the operating pressure of the vacuum rectification column; is −0.08 to −0.1 MPa, the operating temperature is 60 to 120° C., and part of the HCl product gas exiting the top of the HCl rectification column with a purity greater than 99.99% is subjected to a dry etching process. The other part is liquefied and then recycled as an absorbent in the chlorosilane/HCl spray absorption process, and the bottom effluent of the HCl rectification column is fed into the vacuum rectification column for vacuum purification. The overhead gas flowing out from the top of the distillation column is the non-condensable gas 7, part of which is sent to the subsequent exhaust gas absorption process, the other part is returned to the intermediate temperature pressure swing adsorption process, and is returned to the bottom of the vacuum rectification column. a portion of the heavy components flowing out from the HCI is returned to the multi-stage evaporation-compression-condensation step and the other portion is sent to the weak-cold rectification step in chlorosilane;
(7) including a rectification column, into which the crude chlorosilane liquid from the multi-stage evaporation, compression and condensation process and/or the heavy component fluid at the bottom of the vacuum column from the HCl refining process is entered, and the operating temperature is -35 to 10°C; The operating pressure is 0.6 to 2.0 MPa, and the noncondensable gas 8 flowing out from the top of the rectification column is heat-exchanged, returned to the intermediate temperature pressure swing adsorption step, and discharged from the bottom of the rectification column. Part of the effluent chlorosilane liquid is mixed with HCl to form a mixed liquid, and recycled back to the chlorosilane/HCl spray absorption process as an absorbent, and another part is mixed with sulfuric acid to absorb the exhaust gas absorption process. A weak cold rectification step in chlorosilane used as an agent,
(8) Adopting as a reactor the exhaust gas absorption tower using a mixed liquid of chlorosilane liquid and sulfuric acid from the weak-cold rectification process in chlorosilane as an absorbent, and distilled at the top of the upper rectification tower from the HF rectification process Foreign matter gas of light components, non-condensable gas 5 formed through condensation of heavy components flowing out from the bottom of the lower rectification column from the HF rectification step, and non-condensable gas 7 from the HCl refining step are fed into the flue gas absorption tower. Then, a fluorosilicic acid solution is formed at the bottom of the absorption tower, sent out as a raw material, and recycled as a raw material liquid in the production process of preparing AHF by the fluorosilicic acid removal method, and the noncondensable gas 9 flowing out from the top of the absorption tower an exhaust gas absorption step for directly discharging as an exhaust gas,
A method for separating, collecting, recycling, and reusing HF/HCl-containing etching exhaust gas by FTrPSA, comprising: The method for separating, recovering, recycling and reusing HF/HCl-containing etching exhaust gas by FTrPSA according to claim 1, wherein when the content of HCl in the raw gas is less than 1%, the purified raw gas is directly entered into the intermediate temperature pressure swing adsorption step, 1# Uncondensable gas 2 formed by condensation of the crude HF gas flowing out from the top of the PSA column is subjected to microfiltration and absorption with deionized water to obtain an HF aqueous solution with a concentration of 40%, which is sent outside, The non-condensable gas 3 formed via water absorption is the hydrogen-rich gas, which is delivered and used as a fuel gas or used as a feed gas for hydrogen purification by pressure swing adsorption and the crude HF formed via condensation. The liquid is subjected to microfiltration before entering the HF rectification process, and the desorption gas flowing out from the bottom of the 1#PSA adsorption tower in the desorption step is pressurized and heat exchanged before entering from the bottom of the 2#PSA adsorption tower. Then, the non-adsorbed phase intermediate gas flowing out from the top of the 2#PSA adsorption tower in the adsorption step is directly returned to the 1#PSA adsorption tower, and the effective components are recovered, and the bottom of the 2#PSA adsorption tower is The outflowing desorption gas is a concentrated gas, and the non-condensable gas 1 formed after passing through the newly added condenser is further mixed with the crude HF gas in the intermediate temperature pressure swing adsorption process to recover the active ingredient HF, and the newly added condenser. The liquid formed after the condenser is introduced directly into the HCl purification process to recover HCl, and the heavy components flowing out of the HCl purification process are treated before being discharged directly, resulting in chlorosilane/HCl spray absorption, multi-stage evaporation. The method for separation, recovery, recycling and recycling of HF/HCl-containing etching exhaust gas by FTrPSA according to claim 1, characterized in that the steps of compression/condensation and medium-to-low-cold chlorosilane rectification are omitted. In the method for separating, collecting, recycling, and reusing HF/HCl-containing etching exhaust gas by FTrPSA according to claim 1, when the concentration of HF in the source gas is lower than the concentration of HCl, the purified source gas from the pretreatment step is heated up to 80 to 160°C. After heat exchange, it is introduced into the chlorosilane/HCl spray absorption process, and the noncondensable gas 2 formed through condensation of the noncondensable gas 1 flowing out from the top of the spray absorption tower is further passed to the intermediate temperature pressure swing adsorption process comprising two stages of PSA. and the condensed liquid formed through condensation directly enters the HCl purification process, and the absorbent exiting from the bottom of the spray absorption tower enters the multi-stage evaporation-compression-condensation process. Separation, collection, circulation and reuse of HF/HCl-containing etching exhaust gas by FTrPSA. In the method for separating, collecting, recycling, and reusing HF/HCl-containing etching exhaust gas by FTrPSA according to claim 1, when the concentration of HF in the source gas is lower than the concentration of HCl, the purified source gas from the pretreatment step is heated up to 80 to 160°C. After heat exchange, it is introduced into the chlorosilane/HCl spray absorption process, and the noncondensable gas 2 formed through condensation of the noncondensable gas 1 flowing out from the top of the spray absorption tower is further passed to the intermediate temperature pressure swing adsorption process comprising two stages of PSA. The non-condensable gas 2 is introduced from the bottom of the 1#PSA adsorption tower, the operating pressure of 1#PSA is 0.2-0.3MPa, the operating temperature is 50-80 ℃, and it is in the adsorption step. The non-adsorbed phase gas flowing out from the top of the adsorption tower is the intermediate gas, which enters the bottom of the 2#PSA adsorption tower, and the non-adsorbed phase gas flowing out from the top of the adsorption tower in the adsorption step is the crude HF gas. The uncondensable gas 3 formed through condensation is subjected to microfiltration and absorption with deionized water to obtain an HF aqueous solution with a concentration of 40%, which is sent out to the outside, and the noncondensable gas 4 formed through water absorption. is a hydrogen-rich gas, which is delivered and used as a fuel gas or as a feed gas for hydrogen purification by pressure swing adsorption, and the crude HF liquid formed via condensation is microfiltered before HF rectification The desorbed gas from the bottom of the 1#PSA adsorption tower in the desorption step and the concentrated gas from the bottom of the 2#PSA adsorption tower are respectively returned to the chlorosilane/HCl spray absorption process to further recover the effective ingredients. The condensed liquid formed by the condensation of the non-condensable gas 1 is directly entered into the HCl purification process, and the absorbent flowing out from the bottom of the spray absorption tower is entered into the multi-stage evaporation, compression and condensation process. Item 3. A method for separating, collecting, recycling, and reusing HF/HCl-containing etching exhaust gas by FTrPSA according to item 3. In the method for separating, collecting, recycling, and reusing HF/HCl-containing etching exhaust gas by FTrPSA according to claim 1, if the total concentration of HF and HCl in the source gas does not exceed 3%, the source gas is subjected to a pretreatment step. The resulting purified feed gas directly enters a medium temperature pressure swing adsorption process consisting of a single-stage PSA, wherein the single-stage PSA consists of two or more adsorption towers, one adsorption tower is in the adsorption step, and the remaining adsorption towers are in the desorption step including different stages of depressurization/reverse venting or evacuation, pressure increase or final gas filling, the operating pressure of the adsorption tower is 0.2-0.3 MPa, the operating temperature is 70-90° C., Purified feed gas enters from the bottom of the PSA adsorption tower and the non-adsorbed phase gas exiting from the top of the adsorption tower in the adsorption step is the adsorption waste gas, which is used as fuel gas or hydrogen by pressure swing adsorption. The non-condensable gas 1, which is used as the raw material gas for purification and is formed through condensation of the concentrated gas flowing out from the bottom of the adsorption tower in the desorption step, is mixed with the purified raw material gas and returned to the intermediate temperature pressure swing adsorption step, and furthermore the active ingredient is is recovered, the condensed liquid formed through condensation is further entered into the HF rectification process, and the non-condensable gas 2 flowing out of the HF rectification process is entered into the exhaust gas absorption process for treatment, and is discharged from the HF rectification process The HF product gas is recycled back to the dry etching process, and the heavy component fluid exiting the bottom of the HF rectification column directly enters the HCl purification step, thus obtaining the HCl product gas, which is used in the dry etching process. The process of chlorosilane/HCl spray absorption, multi-stage evaporation/compression/condensation, and medium-low-cold chlorosilane rectification process is omitted. 2. The method for separating, recovering, recycling, and reusing HF/HCl-containing etching exhaust gas by FTrPSA according to claim 1, which is also suitable for separating, recovering, and reusing HCl-containing acidic exhaust gas. In the method for separating, collecting, recycling, and reusing HF/HCl-containing etching exhaust gas by FTrPSA according to claim 1, when the concentration of HF/HCl in the raw material gas exceeds 20%, the purified raw material gas that has undergone the pretreatment process is condensed. The non-condensable gas 1 formed through water washing is washed with water to desorb a small amount of residual acidic components, dilute acid is generated and sent out, and the non-condensable gas 2 formed through water washing is used as fuel gas or pressure. Used as a raw material gas for hydrogen purification by swing adsorption, the condensate formed through condensation is sent to the HF rectification process, and the non-condensable gas 3 flowing out from the HF rectification process is sent to the exhaust gas absorption process for treatment, The HF product gas exiting the HF rectification step is recycled back into the dry etching process, and the heavies stream exiting the bottom of the HF rectification column directly enters the HCl purification step, thus recycling the HCl product gas. Then, the chlorosilane/HCl spray absorption, multi-stage evaporation/compression/condensation, medium-weak cold chlorosilane rectification and medium-temperature pressure swing adsorption processes are eliminated, and the operating conditions are changed after plasma cleaning. 2. The method for separating, recovering, recycling, and reusing HF/HCl-containing etching exhaust gas by FTrPSA according to claim 1, which is also suitable for separating, recovering, and reusing the generated high-concentration HF/HCl-containing exhaust gas. In the method for separating, collecting, recycling, and reusing HF/HCl-containing etching exhaust gas by FTrPSA according to claim 1, in the medium-temperature pressure swing adsorption step, noncondensable gas or adsorption waste generated after washing the raw material gas for hydrogen purification by pressure swing adsorption with water. First, non-condensable gas or adsorption waste gas enters the drying tower to desorb moisture and acidic components containing a small amount of fluorine and chlorine, and then enters the adsorption purification stage, silane, Phosphorane and foreign substances including metal ions are desorbed to obtain hydrogen-enriched purified methane-hydrogen gas, pressurized to 1.0-3.0 MPa, heat exchanged to normal temperature, and adsorption of 4 or more Entering a hydrogen purification process by pressure swing adsorption consisting of a tower, ultra-pure hydrogen with a purity of 99.99 to 99.999% flows out from the top of the adsorption tower, and it is a hydrogen gas purification process consisting of a palladium membrane or a metal getter. to obtain a _H2 product gas that meets electronic grade hydrogen gas standards, and either recycled back into the dry etching process or sent out, and the desorption gas exiting the bottom of the adsorption tower is a methane-rich gas , and is directly used as a fuel gas.