System and method for carbon capture in a semiconductor fabrication facility

Abstract

Semiconductor device manufacturing processes generate a waste gas containing carbon dioxide and an aqueous solution containing calcium ions. To perform carbon capture, the carbon dioxide-containing waste gas reacts with the calcium-ion-containing aqueous solution to form solid calcium carbonate. A carbon capture device for a semiconductor manufacturing facility includes: a buffer tank operatively connected to receive aqueous wastewater from a fluoride removal system of the semiconductor manufacturing facility, which reacts fluoride-containing wastewater with calcium chloride; the buffer tank containing calcium-ion-containing aqueous alkaline wastewater; and a reactor configured to capture carbon from the waste gas generated by the semiconductor manufacturing facility by reacting carbon dioxide in the waste gas with the calcium-ion-containing aqueous alkaline wastewater transferred from the buffer tank to the reactor to produce solid calcium carbonate.

Description

[Technical Field]

[0001] Embodiments of the present invention relate to a method for processing waste generated by a semiconductor manufacturing facility and a carbon capture device for a semiconductor manufacturing facility. [Previous Technology]

[0002] The following relates to environmentally friendly semiconductor manufacturing facilities, carbon capture in semiconductor manufacturing facilities, wastewater and exhaust gas treatment in semiconductor manufacturing facilities, and the like. [Summary of the Invention]

[0003] In a non-limiting exemplary embodiment, a method for treating waste generated by a semiconductor manufacturing facility includes: performing semiconductor device manufacturing processes, which generate a waste gas containing carbon dioxide and an aqueous solution containing calcium ions; and reacting the waste gas containing carbon dioxide and the aqueous solution containing calcium ions to form solid calcium carbonate.

[0004] In a non-limiting exemplary embodiment, a method for treating waste generated by a semiconductor manufacturing facility includes: incinerating volatile organic compounds in an emission gas generated by the semiconductor manufacturing facility to generate a waste gas containing carbon dioxide; reacting fluoride-containing wastewater generated by the semiconductor manufacturing facility with calcium chloride to generate solid calcium fluoride and an aqueous solution containing calcium ions; and capturing carbon from the emission gas by reacting the waste gas containing carbon dioxide and the aqueous solution containing calcium ions to form solid calcium carbonate.

[0005] In a non-limiting exemplary embodiment, a carbon capture device for a semiconductor manufacturing facility includes: a buffer tank operatively connected to receive aqueous wastewater from a fluoride removal system of the semiconductor manufacturing facility that reacts fluoride-containing wastewater with calcium chloride, the buffer tank containing aqueous alkaline wastewater containing calcium ions; and a reactor configured to capture carbon from exhaust gases generated by the semiconductor manufacturing facility by reacting carbon dioxide in the exhaust gases with the aqueous alkaline wastewater containing calcium ions transferred from the buffer tank to the reactor to produce solid calcium carbonate.

Implementation Method

[0011] The following disclosure provides numerous different embodiments or examples for implementing different features of the provided object. Specific examples of components and configurations are described below to simplify this disclosure. Of course, these are merely examples and are not intended to be limiting. For example, in the following description, forming a first feature above or on a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features such that the first and second features may not be in direct contact. Furthermore, reference numerals and / or letters may be repeated in various examples of this disclosure. This repetition is for the purpose of simplification and clarity and does not in itself specify a relationship between the various embodiments and / or configurations discussed.

[0012] Additionally, for ease of explanation, this document may use spatially related terms such as "under," "below," "below," "above," "on top," and similar terms to describe the relationship of one element or feature relative to another element(s) as illustrated in the figures. Apart from the orientations shown in the figures, the spatially related terms are intended to cover different orientations of the device during use or operation. The device can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially related terms used herein may be interpreted accordingly.

[0013] Semiconductor manufacturing facilities utilize a wide range of chemicals in various industrial-scale chemical reactions. Many of these reactions employ organic compounds and produce greenhouse gases as reaction byproducts, particularly carbon dioxide (CO2). For example, semiconductor manufacturing processes such as dry etching, chemical vapor deposition (CVD), physical vapor deposition (PVD), and metal-organic vapor phase epitaxy (MOVPE) involve organic reactants or precursors and typically generate volatile organic compounds as waste. Semiconductor facilities also utilize large quantities of deionized water, to the point that deionized (DI) water (e.g., ultrapure deionized water (UPDI), as a non-limiting illustrative example of DI water) is often manufactured on-site. UPDI manufacturing involves removing carbon components such as carbonate ions (CO3 2-) from the water, thus creating further carbon waste byproducts.

[0014] Carbon waste generated by semiconductor manufacturing facilities can ultimately be released into the atmosphere as carbon dioxide. However, atmospheric carbon dioxide absorbs and captures specific wavelengths of electromagnetic radiation, which has been identified as a process that contributes to climate change (e.g., global warming).

[0015] Carbon capture technology can be used to capture some of these waste carbon byproducts to prevent their release into the atmosphere. However, implementing carbon capture at semiconductor manufacturing facilities involves transporting additional chemicals that will be used during the carbon capture process. The additional delivery of chemicals increases the recurring operating costs of the semiconductor manufacturing facility. The additional delivery of chemicals also contributes to the chemical waste footprint of the semiconductor manufacturing facility by increasing its waste output.

[0016] The embodiments disclosed herein provide on-site carbon capture at a semiconductor manufacturing facility, wherein the chemicals used for carbon capture treatment are obtained from waste generated by the semiconductor manufacturing facility. In a suitable method, semiconductor device manufacturing processes are performed at a semiconductor manufacturing facility that generates a waste gas containing carbon dioxide and an aqueous solution containing calcium ions. The waste gas containing carbon dioxide and the aqueous solution containing calcium ions are reacted at the semiconductor manufacturing facility to form solid calcium carbonate.

[0017] Semiconductor device manufacturing processes are performed at a semiconductor manufacturing facility to produce semiconductor devices (or batches of semiconductor devices). As some non-limiting exemplary examples, a semiconductor device may include an integrated circuit (IC) or a batch of ICs, a solid-state memory device (e.g., DRAM, flash memory, etc.) or a batch of solid-state memory devices, a microelectromechanical system (MEMS) device or a batch of MEMS devices, a combination thereof (e.g., an integrated circuit having integrated memory), etc.

[0018] Semiconductor device manufacturing processes can directly facilitate the manufacture of semiconductor devices (i.e., directly process semiconductor wafers), and / or semiconductor device manufacturing processes can constitute the on-site manufacture of chemicals used in the manufacture of semiconductor devices, and / or semiconductor device manufacturing processes can constitute the treatment of byproducts of semiconductor device manufacturing. Some non-limiting exemplary examples of semiconductor device manufacturing processes that directly facilitate the manufacture of semiconductor devices include dry etching, CVD, photoresist deposition, exposure and development, wafer bonding processes, and / or the like. One non-limiting exemplary example of a semiconductor device manufacturing process that presents the form of on-site manufacture of chemicals used in the manufacture of semiconductor devices includes: on-site manufacture of deionized water (e.g., UPDI, as a non-limiting exemplary example) used in the manufacture of semiconductor devices.

[0019] One non-limiting exemplary example of a semiconductor device manufacturing process that presents the treatment of byproducts of semiconductor device manufacturing includes: an F+ curing process for removing harmful fluoride ions from fluoride-containing wastewater generated by, for example, wafer etching in a hydrofluoric acid solution. The F+ curing process involves reacting the fluoride-containing wastewater with calcium chloride (CaCl2) to form a calcium fluoride precipitate according to the reaction: Ca2++ 2F -→ CaF2(s).

[0020] Semiconductor device manufacturing processes performed in semiconductor manufacturing facilities that generate waste gas containing carbon dioxide and aqueous solutions containing calcium ions may include a combination of procedures. For example, semiconductor device manufacturing processes may include a combination of: DI manufacturing that generates at least a portion of waste gas containing carbon dioxide; wet etching of semiconductor wafers using a hydrofluoric acid solution in the manufactured DI; and F+ curing treatment of fluoride wastewater from the wet etching (which generates at least a portion of an aqueous solution containing calcium ions). It should be understood that the foregoing are merely some non-limiting illustrative examples of types of semiconductor device manufacturing processes.

[0021] Carbon dioxide-containing waste gas and a calcium-containing aqueous alkaline solution react at the semiconductor manufacturing facility to form solid calcium carbonate (CaCO3), thus achieving carbon capture. The disclosed method advantageously utilizes the aqueous alkaline byproducts of semiconductor device manufacturing and processing, and optionally other such byproducts, to perform carbon capture. Therefore, it is not necessary to transport additional chemicals to the semiconductor manufacturing facility for on-site carbon capture (or at least, a reduced amount of chemicals is required to transport to the semiconductor manufacturing facility for on-site carbon capture).

[0022] Referring to Figure 1, a carbon capture method according to one embodiment is schematically illustrated for treating wastewater and exhaust gas generated during semiconductor device manufacturing processes performed in a semiconductor manufacturing facility. The carbon capture method utilizes wastewater 10 from deionized water (DI) manufacturing (in an exemplary embodiment, the DI manufacturing is ultrapure deionized water (UPDI) manufacturing, as a non-limiting exemplary example) and exhaust gas 12 from DI manufacturing. During the production of DI water, a degassing tower is used to remove HCO3- from the water. In the degassing tower, the treated water system comes into contact with air injected from the atmosphere by a blower, and carbon dioxide (CO2) is converted from the liquid phase (HCO3-) to the gas phase (CO2). Wastewater 10 from DI manufacturing provides hydroxide ions (OH-) for the carbon capture reaction, while exhaust gas 12 from DI manufacturing, which contains carbon dioxide, will capture carbon dioxide from it. In some unrestricted examples, exhaust gas 12 from DI manufacturing contains approximately 1,500 ppm of carbon dioxide (before carbon capture).

[0023] Another example of a carbon dioxide-containing waste gas from which carbon dioxide is captured is waste gas 14, which originates from the incineration of volatile organic compounds (VOCs) generated during semiconductor device manufacturing processes performed in a semiconductor device manufacturing facility. For example, the waste gas containing VOCs may be the exhaust gas from a CVD tool using an organic precursor gas in a deposition process, and / or the exhaust gas from a dry etching tool using an organic gas as an etchant. These are merely non-limiting illustrative examples. In a typical VOC treatment process, the waste gas containing VOCs is passed through a silica (SiO2) bed, which absorbs and desorbs high concentrations of VOCs from the exhaust gas. This is then sent to a combustion furnace for combustion. The resulting waste gas contains a relatively high concentration of carbon dioxide and is at a temperature of approximately 180-200 °C. In some non-limiting examples, waste gas 14 contains approximately 15,000 ppm of carbon dioxide after incineration (before carbon capture).

[0024] An example of an aqueous solution containing calcium ions generated during typical semiconductor device manufacturing processes performed in a semiconductor manufacturing facility is a byproduct of an F+ curing process 16 used to remove harmful fluoride ions from fluoride-containing wastewater 18 generated by, for example, wafer etching in a hydrofluoric acid solution. The F+ curing process 16 involves reacting the fluoride-containing wastewater 18 with calcium chloride (CaCl2) 20 to form a calcium fluoride precipitate, according to the F+ curing process reaction formula: Ca 2+ + 2F- → CaF 2(s) (1) Wastewater 22 from F+ curing process 16 contains excessive calcium ions (Ca 2+), and therefore wastewater 22 from F+ curing process 16 constitutes an aqueous solution containing calcium ions produced in the semiconductor device manufacturing process (i.e., F+ curing process 16) performed in the semiconductor manufacturing facility.

[0025] The carbon capture procedure in Figure 1 utilizes the following chemical reactions: a first reaction 24, which reacts carbon dioxide in exhaust gases 12 and 14 containing carbon dioxide with hydroxide ions in an alkaline aqueous environment to convert carbon dioxide into aqueous carbonate ions (CO3 2-); and a second reaction 26, which reacts carbonate ions with aqueous calcium ions (Ca2+) to produce solid calcium carbonate (CaCO3(s)) precipitate. The first reaction 24 is as follows: CO2 + 2OH - → CO3 2- + H2O (2) And the second reaction 26 is: Ca 2+ + CO3 2- + H2O → CaCO 3 (s) + H2O (3) The carbon dioxide (CO 2) reactant in the first reaction 24 is carbon dioxide captured from exhaust gases 12 and 14, and the solid calcium carbonate (CaCO 3 (s)) product in the second reaction 26 is carbon captured in the form of calcium carbonate precipitate.

[0026] The first reaction 24 requires an aqueous alkaline solution. Figure 1 includes a diagram 30 showing the fraction of reaction product species as a function of pH produced by the first reaction 24. As seen in Figure 30, if the aqueous solution is acidic, the dominant species fraction is carbon dioxide (CO2), indicating that the first reaction 24 has not occurred. For a relatively neutral pH level, the dominant species fraction is the polyatomic anion HCO3-. For a pH of at least 10, the desired carbonate (CO32-) ion becomes a dominant species fraction, and as seen in Figure 30, above a pH of about 10.3, the species fraction of carbonate (CO32-) ions exceeds that of the polyatomic anion HCO3-. Therefore, in some embodiments, the aqueous alkaline solution in which the first reaction 24 occurs has a pH of at least 10, and in some embodiments, a pH higher than 10.3.

[0027] This relatively high pH (e.g., at least 10 in some embodiments) is advantageously obtained at least in part by the concentration of hydroxide ions (OH-) in the aqueous alkaline solution. This can be obtained at least in part from wastewater 10 from DI production. To increase alkalinity, sodium hydroxide (NaOH) 32 can optionally be added to the aqueous alkaline solution to increase its alkalinity. Sodium hydroxide has a pH of at least 12, such that a relatively small amount of sodium hydroxide 32 can increase the alkalinity to a desired pH of 10 or higher. Although sodium hydroxide 32 is illustrated in Figure 1 as a suitable alkaline chemical substance for addition to an aqueous alkaline solution to increase its alkalinity, other types of alkaline (i.e., water-soluble) bases or solutions containing alkaline bases are considered for this purpose.

[0028] The second reaction 26 can occur in the same aqueous alkaline solution as the first reaction 24, such that the carbon dioxide-containing waste gases 12, 14 and the aqueous alkaline solution containing calcium ions react to form solid calcium carbonate by combining the first reaction 24, which generates carbonate (CO3 2-) ions that act as reactants in the second reaction 26, as schematically indicated by the connecting arrow 34 in Figure 1. As seen in the second reaction 26 given in Equation 3, the calcium carbonate product (CaCO3(s)) is a solid (as indicated by the suffix ""), and the calcium carbonate precipitates from the solution to form recovered solid calcium carbonate 36. This calcium carbonate 36 (or more precisely, its carbon component) constitutes the captured carbon, which is removed from the carbon dioxide-containing waste gases 12, 14. Advantageously, calcium carbonate has a wide range of uses, such as as a building material or cement component in the construction industry, or as limestone aggregate in road construction. Therefore, the recovered solid calcium carbonate 36 is a marketable product that can be sold by semiconductor manufacturing facilities to at least partially offset the costs of implementing carbon capture (such as the cost of purchasing sodium hydroxide 32).

[0029] Referring now to FIG. 2, a non-limiting exemplary embodiment of a carbon capture system for a semiconductor manufacturing facility 40 is schematically illustrated. The carbon capture system is typically located (concretely indicated) at the semiconductor manufacturing facility 40 housing semiconductor processing equipment 42 for performing semiconductor device manufacturing processes. The semiconductor processing equipment 42 may include, for example, dry etching tools, chemical vapor deposition (CVD) tools, physical vapor deposition (CVD) tools, etc., which generate an exhaust gas 44 containing volatile organic compounds (VOCs) (which contain the carbon to be captured). The exhaust gas 44 containing VOCs (i.e., waste gas) passes through a silica (SiO2) bed 46, which absorbs and desorbs the VOCs from the exhaust gas 44, resulting in silica 48 containing the absorbed VOCs, which is then sent to a combustion furnace 50 for combustion. The waste gas produced by combustion (i.e., incineration) contains a relatively high concentration of carbon dioxide (CO2). In some non-limiting examples, the exhaust gas after combustion contains approximately 15,000 ppm of carbon dioxide. In some non-limiting embodiments, the exhaust gas produced by combustion is also relatively hot, exiting the combustion furnace 50 at a temperature of approximately 180–200 °C. Alternatively, this hot exhaust gas passes through a heat exchanger 52 to cool it before it is treated to capture carbon.

[0030] Processing equipment 42 is also used to perform semiconductor device manufacturing processes, generating fluoride-containing wastewater 54. For example, processing equipment 42 may include: a wet etching station that uses a hydrofluoric acid solution to wet etch the semiconductor device under manufacturing; and / or a cleaning station that uses a cleaning fluid containing hydrofluoric acid to clean the semiconductor device under manufacturing. As a non-limiting illustrative example only, a buffered oxide etching containing a mixture of hydrofluoric acid and buffered ammonium fluoride (NH4F) can be used for silicon treatment to etch silicon dioxide or silicon nitride films. Wastewater 54 from these processes contains a relatively high concentration of fluoride, which is removed by an F+ curing process performed in a tank 56. The F+ curing process uses calcium chloride (CaCl2) to capture fluoride according to the reaction Ca2++ 2F → CaF2(s). Most of the fluoride is removed from wastewater 54 in the form of solid calcium fluoride (CaF₂), which precipitates out in tank 56. The wastewater leaving tank 56 constitutes an aqueous solution containing calcium ions.

[0031] The exemplary semiconductor manufacturing facility 40 further performs semiconductor device manufacturing processes including deionized (DI) water production (e.g., ultrapure deionized water (UPDI) production in a non-limiting exemplary example), which is carried out at least in part using an UPDI (or more generally, DI) degassing tower 58 and a resin tower 59. In the degassing tower 58, the water system comes into contact with air injected from the atmosphere by a blower (not shown), and carbon dioxide (CO2) is converted from the liquid phase (HCO3-) to the gas phase (CO2). The exhaust gas from DI production, which contains carbon dioxide, is used to capture carbon dioxide. In some non-limiting examples, the exhaust gas from DI production contains about 1500 ppm of carbon dioxide (before carbon capture).

[0032] The exemplary semiconductor manufacturing facility 40 further includes a carbon capture device comprising a circulation tank 62 and a programmable controller 64. The circulation tank 62 receives exhaust gas containing carbon dioxide via a fitting or pipe body 66. As seen in FIG2, the fitting or pipe body 66 is connected to receive exhaust gas containing carbon dioxide, which is generated from exhaust gas 44 after combustion in a combustion furnace 50 to convert volatile organic compounds into carbon dioxide and optionally cooling the gas leaving the combustion furnace 50 using a heat exchanger 52. Exhaust gas from DI manufacturing (e.g., leaving a degassing tower 58) also contains a significant amount of carbon dioxide (e.g., approximately 1500 ppm of carbon dioxide in a non-limiting exemplary example), and in the exemplary example of FIG2, the carbon dioxide-containing exhaust gas from the degassing tower 58 also flows into the fitting or pipe body 66 for carbon capture by the carbon capture device.

[0033] The carbon capture device also receives an aqueous solution containing calcium ions generated during semiconductor manufacturing processes. In the illustrative example of Figure 2, the received aqueous solution containing calcium ions includes wastewater exiting from the F+ curing process tank 56 via a fitting or pipe 68, and wastewater exiting from DI manufacturing (e.g., exiting resin tower 59) via a fitting or pipe 70. In the DI water manufacturing process, acidic and alkaline wastewater are generated during the regeneration of resin tower 59. Alkaline wastewater can be used to adjust the pH, and acidic wastewater can provide a solution containing calcium ions.

[0034] In the embodiment of FIG2, the circulation tank 62 receives an aqueous solution containing calcium ions from pipes or tubes 68 and 70. By immersing the outlet of the pipe or tube 66 in the aqueous solution 72 to form an aerator configuration, exhaust gas containing carbon dioxide is injected into the calcium ion-containing aqueous solution 72 contained in the circulation tank 62. Alternatively, the outlet of the pipe or tube 66 immersed in the aqueous solution 72 may include a gas diffuser to improve the injection of carbon dioxide-containing exhaust gas into the aqueous solution 72.

[0035] Referring to Figure 2 and further back to Figure 1, the circulation tank 62 is configured to react the carbon dioxide in the exhaust gas delivered by the pipe or pipe body 66 with the aqueous wastewater containing calcium ions delivered by the pipe or pipe body 68 and 70 through the first reaction 24: CO 2 + 2OH -→ CO 3 2- + H 2O (i.e., Equation 2), converting the carbon dioxide into aqueous carbonate ions (CO 3 2-); and through the second reaction 26: Ca 2++ CO 3 2-+ H 2O → CaCO 3 (s)+ H 2O (i.e., Equation 3), converting the aqueous carbonate ions into calcium carbonate precipitate (CaCO 3 (s)) 36. As previously discussed with reference to Figure 1, when the pH is at least 10, the first reaction 24 is operated to primarily produce aqueous carbonate ions (CO 3 2-). When the pH is at least 10.3, the fraction of aqueous carbonate ions exceeds the fraction of polyatomic anions (HCO3-), as shown in Figure 1, illustration 30. Accordingly, the aqueous solution 72 contained in the circulation tank 62 should be an alkaline solution. In some embodiments, the aqueous alkaline solution 72 has a pH of at least 10. In some embodiments, the aqueous alkaline solution 72 has a pH of at least 10.3. To maintain the aqueous solution 72 at a sufficiently alkaline state (e.g., pH > 10), the programmable controller 64 can control the flow of calcium-containing aqueous wastewater delivered by the corresponding fittings or pipes 68 and 70 by operating fluid flow control devices 74 and 76 installed on the corresponding fittings or pipes 68 and 70. Additionally or alternatively, the programmable controller 64 can control the flow of carbon dioxide-containing waste gas into the aqueous solution 72 through the fitting or pipe 66 by using a fluid flow control device 78 installed on the fitting or pipe 66. Various fluid flow control devices 74, 76 and 78 may include, for example, valves, active pumps, plunger pumps, flow restrictors, various combinations thereof and / or the like.

[0036] If the pH of the aqueous solution 72 contained in the circulation tank 62 cannot be maintained at a sufficiently high level (e.g., pH > 10 in some embodiments) by controlling the flow of calcium-containing aqueous wastewater delivered by fittings or pipes 68 and 70 via the corresponding fluid flow control devices 74 and 76, then for this purpose, in some embodiments, an alkaline additive, such as sodium hydroxide (NaOH) or another alkaline base, may be added to the aqueous solution 72. This alkaline additive may be delivered manually or via another fitting or pipe (feature not shown in FIG. 2) controlled by a suitable fluid flow control device controlled by the program controller 64.

[0037] The program controller 64 may be optional—in other embodiments, various fluid flow control devices 74, 76, and 78 (and any additional fluid flow control devices for controlling the delivery of an alkaline additive through a tube or pipe) may be manually operated devices (e.g., pumps with manually adjustable valves and / or flow restrictors). If provided, the program controller 64 may, as a non-limiting exemplary example, be implemented as an electronic controller (e.g., having a microprocessor or microcontroller) connected to the various fluid flow control devices 74, 76, and 78 via wires or wireless communication. Although not shown, a pH sensor may be placed in the circulation tank 62 to monitor the pH of the aqueous alkaline solution 72, and the pH measurement from the pH sensor may be input to the program controller 64. (In a manual embodiment, the pH sensor will be suitably displayed in a human-visible manner to provide information to semiconductor manufacturing facility workers to assist in manual adjustments).

[0038] The carbon capture system further includes an exhaust line 80 that exhausts ambient gas above the aqueous alkaline solution 72 in the tank to an exhaust system 82, which exhausts to a suitable outlet, such as ambient air outside the semiconductor manufacturing facility 40. As a non-limiting exemplary example, the exhaust system 82 may include a volatile organic compound (VEX) exhaust system, an alkaline exhaust (AEX) system, or a combination thereof. Alternatively, a carbon dioxide sensor (not shown) may be included on the exhaust line 80 to monitor the concentration of carbon dioxide in the exhaust gas (e.g., measured in ppm) to record the effectiveness of carbon capture.

[0039] In the embodiment of FIG2, the reactor for carrying out the carbon capture reaction (i.e., equations 1 and 2) includes a circulation tank 62. In this reactor, the contact area between the carbon dioxide-containing exhaust gas delivered by the pipe or tube 66 and the aqueous alkaline solution 72 is relatively limited. This is provided by the exhaust gas being injected into the aqueous alkaline solution 72 through the outlet of the pipe or tube 66, which is immersed in the aqueous alkaline solution 72, optionally assisted by a diffuser installed at the outlet of the pipe or tube 66.

[0040] Referring now to FIG3, a non-limiting exemplary embodiment of a carbon capture system for a semiconductor manufacturing facility 40 is schematically illustrated. The carbon capture system of FIG3 also receives waste gas containing carbon dioxide via a fitting or pipe body 66, and also receives an aqueous solution containing calcium ions, including wastewater exiting the F+ curing process tank 56 received via a fitting or pipe body 68 and wastewater exiting DI manufacturing received via a fitting or pipe body 70. The carbon capture system of FIG3 also includes an exhaust line 80. Although not shown in FIG3, the carbon capture system of FIG3 is suitably located in a semiconductor manufacturing facility similar to the semiconductor manufacturing facility 40 of FIG2, and the facility suitably includes various elements 42, 44, 46, 48, 50, 52, 54, 56, and 58 as illustrated with reference to FIG2. Furthermore, although not shown in FIG3, the carbon capture system of FIG3 may include a programmable controller 64 that controls fluid flow control devices similar to the fluid flow control devices 74, 76, and 78 of FIG2.

[0041] The carbon capture system of Figure 3 provides enhanced pH control of the aqueous alkaline solution 72 in the circulation tank 62 by adding an upstream Ca+ buffer tank 100. The upstream Ca+ buffer tank 100 receives wastewater exiting the F+ curing process tank 56 via fittings or pipes 68 and wastewater exiting the DI manufacturing via fittings or pipes 70. The Ca+ buffer tank 100 contains an aqueous alkaline solution 102 containing calcium ions. When the carbon capture reaction (i.e., equations 1 and 2) does not occur in the Ca+ buffer tank 100, this tank can be used alone to control the pH of the aqueous alkaline solution 102, for example, by controlling the flow through fittings or pipes 68 and 70, and / or by adding an alkaline additive such as sodium hydroxide (NaOH) or another alkaline base to increase the pH of the aqueous alkaline solution 102. In some embodiments, the aqueous alkaline solution 102 in the Ca+ buffer tank 100 has a pH of at least 10. In some embodiments, the aqueous alkaline solution 102 in the Ca+ buffer tank 100 has a pH of at least 10.3.

[0042] The aqueous alkaline solution 102 containing calcium ions, contained in the Ca+ buffer tank 100, is transferred (i.e., flows) to the downstream circulation tank 62 via a fitting or pipe body 104. The flow rate through the fitting or pipe body 104 can be controlled to control the level of the aqueous alkaline solution 72 in the circulation tank 62. The circulation tank 62 of Figure 3 is similar to the circulation tank 62 of Figure 2. As previously noted, in the embodiment of Figure 2, the reactor used to perform the carbon capture reaction includes the circulation tank 62, and therefore there is a limited contact area between the carbon dioxide-containing exhaust gas delivered by the fitting or pipe body 66 and the aqueous alkaline solution 72 contained in the circulation tank 62.

[0043] Referring again to FIG. 3 and further to FIG. 4, in the embodiment of FIG. 3, a reactor is provided to obtain a large contact area between the carbon dioxide-containing exhaust gas delivered by the fitting or tube 66 and the aqueous alkaline solution 72 contained in the circulation tank 62. The reactor includes the circulation tank 62 and further includes a gas atomizer 110. FIG. 4 shows an enlarged separate view of the gas atomizer 110. As marked only in FIG. 4, the gas atomizer 110 includes a housing 112 and a liquid distributor 114. The fitting or tube 116 having a pump (not shown) transfers the aqueous alkaline solution 72 to the upper end of one of the liquid distributors 114, which is rotatable or rotating and has openings along its sidewalls from which the aqueous alkaline solution 72 is discharged as an outwardly directed aqueous alkaline solution (generally indicated by the outwardly directed arrow 118). The fitting or pipe body 66 delivers carbon dioxide-containing exhaust gas into the upper part of the housing 112, where it flows inward, as roughly indicated by the inward-guiding arrow 120. Thus, the liquid and gas are in close contact within a gas-liquid mixing volume 122 inside the housing 112. This provides a favorable large contact volume 122 between the carbon dioxide-containing exhaust gas delivered by the fitting or pipe body 66 and the aqueous alkaline solution 72 contained in the circulation tank 62. Furthermore, as seen in Figure 4, the discharge line 80 is connected near the top of the housing 112.

[0044] Returning to Figure 3, another feature of the carbon capture system in Figure 3 is that it includes a deposition tank 130, which receives the outward flow of the aqueous alkaline solution 72 contained in the circulation tank 62 via a pipe or tube 132. The deposition tank 130 advantageously facilitates solid-liquid separation to recover solid calcium carbonate precipitate (CaCO3), which can then be sold to the construction industry or another commercial industry utilizing calcium carbonate.

[0045] In the following text, some non-limiting illustrative examples of some operating parameters for the carbon capture system of Figure 3 are disclosed.

[0046] In some non-limiting exemplary embodiments, the fitting or pipe body 68 introduces wastewater with a calcium ion (Ca+) concentration of at least 180 ppm from the F+ curing process tank 56 into the buffer tank 100.

[0047] In some non-limiting exemplary embodiments, the fitting or pipe body 70 introduces alkaline wastewater having a pH of at least 8 exiting the resin tower 59. In the DI water production process, acidic and alkaline wastewater are generated during the regeneration of the resin tower 59, and the alkaline wastewater delivered from the resin tower 59 via the fitting or pipe body 70 can be used to adjust the pH of the aqueous alkaline solution 72 in the circulation tank 62.

[0048] In some non-limiting exemplary embodiments, the fitting or pipe body 66 introduces exhaust gas containing carbon dioxide (CO2) at a concentration of at least 1500 ppm.

[0049] In some non-limiting exemplary embodiments, the gas atomizer 110 operates at a pressure of at least 0.5 atmospheres in the gas-liquid mixing volume 122.

[0050] In some non-limiting exemplary embodiments, the program controller may further control a rotational speed of the gas atomizer 110.

[0051] In some non-limiting exemplary embodiments, one or more filters (not shown) may be included at the inlet and / or outlet of one or more of the fittings or bodies 66, 68, 70, 104, 116 and / or 132.

[0052] As previously described with reference to FIG2, the carbon capture system of FIG3 may include a programmable controller 64 and suitable fluid flow control devices (e.g., pumps, plunger pumps, limiting devices, valves, etc.) to manage the flow rates through various fittings or pipes 66, 68, 70 and through various fittings or pipes 104, 116, 132, to optionally control the carbon capture process based on sensor data such as: the pH of the aqueous alkaline solution 102 in Ca+ buffer tank 100 and the aqueous alkaline solution 72 in circulation tank 62 as measured by pH sensors (not shown) in corresponding tanks 100 and 72; and / or the calcium ion concentration as measured by a calcium concentration sensor (or sensor) in one or both of tanks 100 and / or 72 and / or 130. In some embodiments, one or more thermal sensors may also be provided to monitor, for example, the temperature of exhaust gases from the combustion furnace 50 and / or from the heat exchanger 52.

[0053] In the following description, some other embodiments are described.

[0054] In a non-limiting exemplary embodiment, a method for treating waste generated by a semiconductor manufacturing facility includes: performing semiconductor device manufacturing processes, which generate a waste gas containing carbon dioxide and an aqueous solution containing calcium ions; and reacting the waste gas containing carbon dioxide and the aqueous solution containing calcium ions to form solid calcium carbonate.

[0055] In a non-limiting exemplary embodiment, the semiconductor device manufacturing process includes: performing at least one first semiconductor device manufacturing process, which generates an emission gas containing one of the volatile organic compounds; and incinerating the volatile organic compounds to generate an exhaust gas containing carbon dioxide.

[0056] In a non-limiting exemplary embodiment, the manufacturing process of the at least one first semiconductor device includes at least one of the following: etching the material of the semiconductor device under manufacturing using a dry etching system and at least one organic reactive gas; or depositing the material of the semiconductor device under manufacturing using a deposition system and at least one organic gas.

[0057] In a non-limiting exemplary embodiment, the first semiconductor device manufacturing process further includes: absorbing the volatile organic compounds from the exhaust gas into silicon dioxide; wherein the incineration includes incinerating the volatile organic compounds absorbed into the silicon dioxide to generate the exhaust gas containing carbon dioxide.

[0058] In a non-limiting exemplary embodiment, the semiconductor device manufacturing process includes: performing at least one second semiconductor device manufacturing process, which generates fluoride-containing wastewater; and reacting the fluoride-containing wastewater with calcium chloride to generate solid calcium fluoride and the aqueous solution containing calcium ions.

[0059] In a non-limiting exemplary embodiment, the manufacturing process of the at least one second semiconductor device includes: etching and / or cleaning the semiconductor device under manufacturing using a hydrofluoric acid solution.

[0060] In a non-limiting exemplary embodiment, the method further comprises: increasing the alkalinity of the calcium-containing aqueous solution by adding sodium hydroxide and / or water output from a deionized water manufacturing process to the calcium-containing aqueous solution output from the reaction of the fluoride-containing wastewater and calcium chloride.

[0061] In a non-limiting exemplary embodiment, the method further includes: increasing the alkalinity of the aqueous solution containing calcium ions in a buffer tank; transferring the aqueous solution containing calcium ions from the buffer tank to a circulation tank; wherein the reaction between the carbon dioxide-containing waste gas and the aqueous solution containing calcium ions takes place in the circulation tank.

[0062] In a non-limiting exemplary embodiment, the method further includes: the reaction of the carbon dioxide-containing waste gas and the calcium ion-containing aqueous solution in the circulation tank is carried out using a gas atomizer, wherein the carbon dioxide-containing waste gas is introduced into the gas atomizer, and the calcium ion-containing aqueous solution is pumped from the circulation tank into the gas atomizer.

[0063] In a non-limiting exemplary embodiment, the semiconductor device manufacturing process includes: manufacturing deionized water, wherein at least one of the following is present: (i) the carbon dioxide-containing waste gas includes carbon dioxide vapor output from the manufacturing of the deionized water; and / or (ii) the calcium ion-containing aqueous solution includes wastewater output from the manufacturing of the deionized water.

[0064] In a non-limiting exemplary embodiment, the reaction of carbon dioxide-containing waste gas with an aqueous solution containing calcium ions is carried out using a circulation tank containing the aqueous solution containing calcium ions, and the method further includes: transferring wastewater from the circulation tank to a sedimentation tank; and collecting the solid calcium carbonate in the sedimentation tank.

[0065] In a non-limiting exemplary embodiment, the aqueous solution containing calcium ions has a pH of at least 10.

[0066] In a non-limiting exemplary embodiment, a method for treating waste generated by a semiconductor manufacturing facility includes: incinerating volatile organic compounds in an emission gas generated by the semiconductor manufacturing facility to generate a waste gas containing carbon dioxide; reacting fluoride-containing wastewater generated by the semiconductor manufacturing facility with calcium chloride to generate solid calcium fluoride and an aqueous solution containing calcium ions; and capturing carbon from the emission gas by reacting the waste gas containing carbon dioxide and the aqueous solution containing calcium ions to form solid calcium carbonate.

[0067] In a non-limiting exemplary embodiment, the method further comprises: absorbing the volatile organic compounds from the exhaust gas into silica; wherein the incineration comprises incinerating the volatile organic compounds absorbed into the silica to generate the exhaust gas containing carbon dioxide.

[0068] In a non-limiting exemplary embodiment, the method further includes: increasing the alkalinity of the aqueous solution containing calcium ions in a buffer tank to make the aqueous solution containing calcium ions a calcium-ion-containing aqueous alkaline solution; transferring the calcium-ion-containing aqueous alkaline solution from the buffer tank to a circulation tank; wherein the reaction is carried out using a gas atomizer, the carbon dioxide-containing exhaust gas is introduced into the gas atomizer, and the calcium-ion-containing aqueous alkaline solution is pumped from the circulation tank to the gas atomizer.

[0069] In a non-limiting exemplary embodiment, the alkalinity of the aqueous alkaline solution containing calcium ions in the buffer tank is increased by adding water output from a deionized water manufacturing process to the buffer tank, and the method further includes adding carbon dioxide vapor output from the deionized water manufacturing process to the carbon dioxide-containing waste gas.

[0070] In a non-limiting exemplary embodiment, a carbon capture device for a semiconductor manufacturing facility includes: a buffer tank operatively connected to receive aqueous wastewater from a fluoride removal system of the semiconductor manufacturing facility that reacts fluoride-containing wastewater with calcium chloride, the buffer tank containing aqueous alkaline wastewater containing calcium ions; and a reactor configured to capture carbon from exhaust gases generated by the semiconductor manufacturing facility by reacting carbon dioxide in the exhaust gases with the aqueous alkaline wastewater containing calcium ions transferred from the buffer tank to the reactor to produce solid calcium carbonate.

[0071] In a non-limiting exemplary embodiment, the reactor is configured to react the carbon dioxide (CO2) in the exhaust gas with the aqueous alkaline wastewater containing calcium ions by converting the carbon dioxide (CO2) into aqueous carbonate ions (CO32-) via the reaction: CO2 + 2OH- → CO32- + H2O, and to convert the aqueous carbonate ions (CO32-) into calcium carbonate precipitate (CaCO3(s)) via the reaction: Ca2++ CO32- + H2O → CaCO3(s) + H2O, wherein the configuration of the reactor includes maintaining the liquid contained in the reactor at a pH of at least 10.

[0072] In a non-limiting exemplary embodiment, the reactor includes: a circulation tank operatively connected to receive the aqueous wastewater from the buffer tank; and a gas atomizer connected to receive the exhaust gas generated by the semiconductor manufacturing facility, and the aqueous alkaline solution delivered from the circulation tank to the gas atomizer.

[0073] The foregoing has summarized the features of several embodiments to enable those skilled in the art to better understand the nature of this disclosure. Those skilled in the art should understand that they can readily use this disclosure as a basis for designing or modifying other processes and structures to perform the same purpose and / or achieve the same advantages of the embodiments introduced herein. Those skilled in the art should also understand that such equivalent constructions do not depart from the spirit and scope of this disclosure, and that they can make various changes, substitutions, and alterations to this document without departing from the spirit and scope of this disclosure. [Simplified Explanation of the Diagram]

[0006] The nature of this disclosure can be best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be noted that, according to industry standard practice, the various features are not drawn to scale. In fact, for clarity of discussion, the dimensions of the various features may be arbitrarily increased or decreased.

[0007] Figure 1 schematically illustrates a carbon capture method for treating wastewater and exhaust gas generated in a semiconductor manufacturing facility according to one embodiment.

[0008] Figure 2 schematically illustrates a carbon capture system of a semiconductor manufacturing facility according to one embodiment.

[0009] Figure 3 schematically illustrates a carbon capture system of a semiconductor manufacturing facility according to one embodiment.

[0010] Figure 4 schematically illustrates a single view of the gas atomizer of the carbon capture system of Figure 3.

Claims

1. A method for treating waste generated from a semiconductor manufacturing facility, the method comprising: performing a semiconductor device manufacturing process that generates a waste gas containing carbon dioxide and an aqueous solution containing calcium ions; and reacting the waste gas containing carbon dioxide and the aqueous solution containing calcium ions to form solid calcium carbonate, wherein the semiconductor device manufacturing process includes: The process involves manufacturing deionized water; wherein the waste gas containing carbon dioxide includes carbon dioxide vapor output from the manufacturing of the deionized water; and wherein the aqueous solution containing calcium ions includes wastewater output from the manufacturing of the deionized water.

2. The method of claim 1, wherein the semiconductor device manufacturing process includes: The manufacturing process of at least one first semiconductor device generates emission gases containing one of the volatile organic compounds. And the incineration of these volatile organic compounds to generate the waste gas containing carbon dioxide.

3. The method of claim 1, wherein the semiconductor device manufacturing process includes: The manufacturing process of at least one second semiconductor device generates fluoride-containing wastewater. And to react the fluoride-containing wastewater with calcium chloride to generate solid calcium fluoride and the aqueous solution containing calcium ions.

4. The method of claim 2, wherein the manufacturing process of the first semiconductor device further includes: The volatile organic compounds are absorbed from the emission gas into silica; wherein the incineration includes incinerating the volatile organic compounds absorbed into the silica to generate the waste gas containing carbon dioxide.

5. The method of claim 1, wherein the reaction of the carbon dioxide-containing waste gas with the aqueous solution containing calcium ions is carried out using a circulation tank containing the aqueous solution containing calcium ions, and the method further includes: The wastewater is transferred from the circulation tank to a sedimentation tank; And to collect the solid calcium carbonate in the deposition tank.

6. The method of claim 1, wherein the aqueous solution containing calcium ions has a pH of at least 10.

7. A method for treating waste generated from a semiconductor manufacturing facility, the method comprising: incinerating volatile organic compounds in an emission gas generated by the semiconductor manufacturing facility to generate a waste gas containing carbon dioxide; reacting fluoride-containing wastewater generated by the semiconductor manufacturing facility with calcium chloride to generate solid calcium fluoride and an aqueous solution containing calcium ions; and capturing carbon from the emission gas by reacting the waste gas containing carbon dioxide and the aqueous solution containing calcium ions to form solid calcium carbonate, wherein the method further comprises: adding carbon dioxide vapor output from a deionized water manufacturing process to the waste gas containing carbon dioxide; and adding the wastewater output from the deionized water manufacturing process to the aqueous solution containing calcium ions.

8. The method of claim 7, further comprising: absorbing the volatile organic compounds from the emission gas into silica; wherein the incineration comprises incinerating the volatile organic compounds absorbed into the silica to generate the waste gas containing carbon dioxide.

9. The method of claim 7, further comprising: increasing the alkalinity of the aqueous solution containing calcium ions in a buffer tank to make the aqueous solution containing calcium ions a calcium-containing aqueous alkaline solution; transferring the calcium-containing aqueous alkaline solution from the buffer tank to a circulation tank; wherein the reaction is carried out using a gas atomizer, the carbon dioxide-containing exhaust gas is introduced into the gas atomizer, and the calcium-containing aqueous alkaline solution is pumped from the circulation tank to the gas atomizer.

10. A carbon capture device for a semiconductor manufacturing facility, the carbon capture device comprising: a buffer tank operatively connected to receive aqueous wastewater from a fluoride removal system of the semiconductor manufacturing facility in which fluoride-containing wastewater is reacted with calcium chloride, and water output from a deionized water production process, the buffer tank containing aqueous alkaline wastewater containing calcium ions; and a reactor configured to capture carbon from exhaust gas generated by the semiconductor manufacturing facility by reacting carbon dioxide in the exhaust gas with the calcium-containing aqueous alkaline wastewater transferred from the buffer tank to the reactor to produce solid calcium carbonate, wherein the exhaust gas includes carbon dioxide vapor output from a deionized water production process.

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