Composite adsorbent-containing materials and related methods

Abstract

The present invention provides a composite adsorbent medium containing two or more different types of adsorbent materials in a binder, which can preferably be prepared by additive manufacturing technology, and a method for preparing a structure by additive manufacturing. [Solution] A composite adsorbent medium comprising first adsorbent particles, second adsorbent particles, and a binder that holds the first adsorbent particles and the second adsorbent particles together as a composite adsorbent medium.

Description

Technical Field

[0001] The described invention relates to a composite adsorption medium containing two or more different types of adsorbent materials and a binder, and preferably capable of being prepared by an additive manufacturing technique, and a method for preparing a structure by an additive manufacturing method.

Background Art

[0002] In the manufacture of semiconductor materials and devices, as well as in various other industrial processes and applications, a reliable source of high purity gaseous materials ("reagent gases") used in chemical treatment or manufacturing processes is required.

[0003] Exemplary reagent gases include, for example, among others, gases used in the processing of semiconductor materials or microelectronic devices by ion implantation, epitaxial growth, plasma etching, reactive ion etching, metallization, physical vapor deposition, chemical vapor deposition, atomic layer deposition, plasma deposition, photolithography, cleaning, and doping, etc., and these uses are included, among others, in methods for manufacturing semiconductor, microelectronic, photovoltaic, and flat panel display devices and products.

[0004] Examples of specific reagent gases used in some of these processes include silane, germane, ammonia, phosphine, arsine, diborane, stibine, hydrogen sulfide, hydrogen selenide, hydrogen telluride, digermane, acetylene, methane, and corresponding and other halide (chlorine, bromine, iodine, and fluorine) compounds. The gaseous hydrides arsine (AsH3) and phosphine (PH3) are commonly used as sources of arsenic (As) and phosphorus (P) in ion implantation. Due to their extreme toxicity and relatively high vapor pressure, the use, transportation, or storage of these gases raises significant safety concerns. These gases must be stored, transported, handled, and used with a high degree of care and many safety precautions.

[0005] One useful embodiment for storing and delivering these types of reagent gases is by an adsorbent storage system. In an adsorbent storage system, a solid adsorbent material is housed in a storage container to which a useful and valuable raw material ("reagent gas") in gaseous form is typically added. The reagent gas is adsorbed onto the surface of the adsorbent material for subsequent release from the storage container.

[0006] The need for extremely high-purity reagent gases used in certain commercial processes is driving ongoing research to improve the purity levels of reagent gases. Much of this research focuses on methods to reduce the levels of impurities present in reagent gases during preparation, storage, transport, and delivery. One specific embodiment of increasing the purity level of reagent gases is filtration to remove impurities. [Overview of the project]

[0007] In one embodiment, the present invention relates to a composite adsorbent medium comprising first adsorbent particles, second adsorbent particles, and a binder that holds the first adsorbent particles and the second adsorbent particles together as a composite adsorbent medium.

[0008] In another aspect, the present invention relates to a method for adsorbing a plurality of different gases contained in a gas mixture onto a composite adsorption medium. The method includes contacting the gas mixture with a composite adsorption medium, wherein the composite adsorption medium comprises first adsorbent particles, second adsorbent particles, and a binder that holds the first adsorbent particles and the second adsorbent particles together as a composite adsorption medium; adsorbing a first gas contained in the gas mixture onto the first adsorbent particles; and adsorbing a second gas contained in the gas mixture onto the second adsorbent particles.

[0009] In another embodiment, the present invention relates to a method for producing a composite adsorbent medium. The method includes forming a first feed material layer on a surface, wherein the feed material layer comprises a feed material containing first adsorbent medium particles and second adsorbent medium particles; forming a solidified feed material from the first feed material layer; forming a second feed material layer on the first feed material layer, wherein the second feed material layer comprises a feed material containing first adsorbent medium particles and second adsorbent medium particles; and forming a second solidified feed material from the second feed material layer. The combined first and second feed material layers form a multilayer composite material containing first adsorbent medium particles and second adsorbent medium particles.

[0010] In yet another embodiment, the present invention relates to a method for preparing a composite adsorbent medium for processing a gas mixture. The method comprises, with respect to a gas mixture containing a first gas and a second gas, selecting first adsorbent particles for adsorbing a first gas, selecting second adsorbent particles for adsorbing a second gas, and forming a composite adsorbent medium, wherein the composite adsorbent medium comprises the first adsorbent particles, the second adsorbent particles, and a binder that holds the first adsorbent particles and the second adsorbent particles together as a composite adsorbent medium. [Brief explanation of the drawing]

[0011] [Figure 1] As described, this figure shows an example of a system and method that uses a composite adsorption medium to separate gases from a gas mixture. [Figure 2A-B] As described, this figure shows an example of a system and method that uses a composite adsorption medium to separate gases from a gas mixture. [Figure 3] As described, this figure shows an example of a system and method that uses a composite adsorption medium to separate gases from a gas mixture. [Figure 4A] This figure shows an exemplary step in a method for forming a multilayer composite adsorption medium by additive manufacturing technology, as described. [Figure 4B] This figure shows an exemplary step in a method for forming a multilayer composite adsorption medium by additive manufacturing technology, as described. [Figure 5A] This figure shows an exemplary step in a method for forming a multilayer composite adsorption medium by additive manufacturing technology, as described. [Figure 5B] This figure shows an exemplary step in a method for forming a multilayer composite adsorption medium by additive manufacturing technology, as described. [Figure 6A] This figure shows an exemplary step in a method for forming a multilayer composite adsorption medium by additive manufacturing technology, as described. [Figure 6B] This figure shows an exemplary step in a method for forming a multilayer composite adsorption medium by additive manufacturing technology, as described. [Figure 7A-C] This figure shows an exemplary step in a method for forming a multilayer composite adsorption medium by additive manufacturing technology, as described. [Modes for carrying out the invention]

[0012] All diagrams are schematic and not to scale.

[0013] The following is a description of a “composite adsorption medium,” meaning an adsorption medium containing at least two different types of adsorbent particles combined in a single solid adsorption medium and held together by a binder. Two different types of adsorbent particles are effective in adsorbing at least two different gaseous components of a gas mixture.

[0014] The composite material is made from a material comprising a first type of adsorbent, a second type of adsorbent that is functionally different from the first type of adsorbent based on its affinity for adsorbing different gases, and a binder. The first and second adsorbents are held together by the binder, forming a porous matrix that constitutes the composite adsorbent medium.

[0015] A preferred composite can be considered relatively "uniform," meaning that the first adsorbent particles, the second adsorbent particles, and any additional adsorbent particles are evenly distributed throughout the composite and held together by a binder that is also evenly distributed throughout the composite.

[0016] At a microscopic scale, for example, when magnified, most or all of the homogeneous composite appears visually substantially similar with respect to the relative amounts of different adsorbent particles and binders, and the different adsorbent particles are distributed substantially equally and uniformly throughout the homogeneous composite, with the first adsorbent particles and the second adsorbent particles present at equal concentrations and similarly distributed throughout the composite.

[0017] Homogeneous composites can also exhibit a substantially uniform composition based on compositional analysis. The chemical composition of a composite can be identified by analytically testing various samples of parts of the composite, such as by testing the metal content (concentration). Samples of homogeneous composites have similar chemical compositions, such as concentrations of one or more metals within 1%, or 0.5% or 0.1%. An example of a useful analytical technique is scanning electron microscopy energy-dispersive spectroscopy (SEM / EDS) (sometimes called energy-dispersive X-ray analysis (EDXA) or energy-dispersive X-ray trace analysis (EDXMA)).

[0018] The composite material contains at least two different types of adsorbent particles, each effective in adsorbing different types of gaseous components of a gas mixture. The different types of adsorbent particles can be selected based on their adsorption properties, which can be obtained based on size selectivity or thermodynamic selectivity. Based on size selectivity, certain types of adsorbents adsorb smaller molecules, while others adsorb larger molecules. Zeolite adsorbents may have smaller pore sizes and can adsorb relatively small particles, such as certain types of impurities (e.g., HF). Based on thermodynamic selectivity, certain types of adsorbents adsorb molecules with different chemical affinities to different chemical molecules.

[0019] In certain examples, the first and second adsorbents can be selected to adsorb two different gases present in a gas mixture that includes a high-value gas, referred to as a "reagent gas," and an impurity gas known to be present in the high-value reagent gas.

[0020] The first adsorbent is selected to effectively adsorb and selectively desorb the reagent gas. Exemplary reagent gases include materials useful in commercial manufacturing processes. Examples include silane, germane, ammonia, phosphine, arsine, diborane, stibine, hydrogen sulfide, hydrogen selenide, hydrogen telluride, digermane, acetylene, methane, and corresponding and other halide (chlorine, bromine, iodine, and fluorine) compounds. The gaseous hydrides arsine (AsH3) and phosphine (PH3) are commonly used as sources of arsenic (As) and phosphorus (P) in ion implantation.

[0021] In these examples, when the first adsorbent is effective at adsorbing a first gas that is a "high-value" reagent gas, the second adsorbent can be effective at adsorbing a second gas that is a unwanted gas present in the reagent gas, such as an impurity gas, that is different from the first gas. The first gas can be a "high-value" gas that is useful in a commercial manufacturing process or is otherwise desired to be collected for its value, while the second gas can be an impurity gas that is known to be present in small amounts along with the first gas as a mixture of the first and second gases. The gas mixture can be a mixture containing a high concentration of a high-value gas (e.g., a reagent gas), such as at least 90, 95, 99, or 99.9% (volume basis), in combination with an impurity gas as the second gas, and the impurity gas can be present in low amounts, such as less than or lower than 0.1, 0.01, or 0.001% (volume basis), in concentrations in the parts per million (ppm) or parts per billion (ppb) range.

[0022] In a specific example, the first gas may be germanium, and the impurity may be digermanium that otherwise exists in a very small amount as an impurity in high-purity germanium. In this specific example, the first adsorbent effective for adsorbing germanium may be a zeolite or a metal-organic framework adsorbent.

[0023] As another example, the gas mixture may contain a reagent gas that is a special hydride or halide containing water as an impurity, a reagent gas that is a hydride (e.g., SiH4, GeH4, AsH3, etc.) and hydrogen as an impurity, and a reagent gas that is phosphine containing diphosphine as an impurity. The reagent gas can be a high-value special gas containing impurities that are hydrated by-products or ionized fragments of high-value special gases. The reagent gas may be a high-value fluoride (such as BF3, GeF4, SiF4, PF3, etc.) containing hydrogen fluoride (HF) as an impurity. Other gas mixtures may be exhaust gases flowing from manufacturing or chemical treatment processes that contain high-value reagent gases containing impurities that are inert gases such as nitrogen, helium, xenon, or argon.

[0024] Preferably, the combination of the first and second adsorbents may be present in relative amounts in the composite adsorption medium to adsorb both the first gas (e.g., a high-value reagent gas) and the second gas (an impurity gas) in approximately the amounts in which they are present in the gas mixture.

[0025] In another example of the composite adsorption medium, the adsorption medium can contain the first and second adsorbents, and each adsorbent is effective for adsorbing impurities known to be present in the reagent gas. The first adsorbent effectively adsorbs the first impurity, the second adsorbent effectively adsorbs the second impurity, and both the first adsorbent and the second adsorbent are not effective for adsorbing the reagent gas.

[0026] Preferably, the combination of the first and second adsorbents in these exemplary composite adsorption media may also be present in relative amounts in the composite adsorption media to adsorb both the first and second gases, both of which are impurities in the reagent gas, in the approximate amounts in which the first and second impurity gases are present in the gas mixture.

[0027] Various different types of adsorbent materials are known and are available as particles for the uses described herein. Common types of adsorbent particles include carbon-based adsorbent particles, polymer adsorbent particles containing porous organic polymers (POPs), polymer structure particles (PFs), zeolite adsorbent particles ("zeolites"), silicalite particles, and metal-organic structure particles (MOFs).

[0028] Useful metal-organic framework (MOF) adsorbent materials exhibit a variety of physical and molecular forms. Metal-organic frameworks are organic-inorganic hybrid crystalline porous materials with a molecular structure containing a regular, repeating arrangement of positively charged metal ions surrounded by organic "linker" molecules. The metal ions bond the arms of the organic linker molecules to each other, forming nodes that create repeating hollow cage-like structures. This hollow structure gives MOFs a very large internal surface area, making them suitable for use in adsorbent storage systems for adsorbing (and selectively desorbing) reagent gases. These features of MOF molecules must be preserved substantially without destruction or damage during useful additive manufacturing processes for forming multilayer composite adsorbent media.

[0029] Metal-organic frameworks (MOFs) are nanoporous materials consisting of organic linkers coordinated to metal ions in a crystalline structure. Various MOF adsorbent materials are known in the fields of reagent gases, reagent gas storage, and gas separation. Specific examples of MOF materials are described in U.S. Patent No. 9,138,720 and U.S. Patent Application Publication No. 2016 / 0130199, the entirety of each of these documents, are incorporated herein by reference.

[0030] A subclass of MOFs known as zeolite adsorbents includes zeolite-type imidazolate structures ("ZIFs") consisting of metals (primarily tetrahedral Zn2) bridged by nitrogen atoms of imidazolate linkers. Zeolite-type imidazolate structures are a type of MOF containing tetrahedral-coordinating transition metals such as iron (Fe), cobalt (Co), copper (Cu), or zinc (Zn), linked by imidazolate linkers, which may be the same or different within a particular ZIF composition or with respect to a single transition metal atom of the ZIF structure. ZIF structures contain four-coordinating transition metals linked via imidazolate units to produce extended structures based on tetrahedral topology. ZIFs are said to form a structural topology equivalent to that found in zeolites and other inorganic microporous oxide materials.

[0031] Zeolite-type imidazolate structures can be characterized by features including, among other physical and chemical properties, the type of transition metal (e.g., iron, cobalt, copper, or zinc), the chemical properties of the linker (e.g., chemical substituents of the imidazolate unit), the pore size of the ZIF, the surface area of ​​the ZIF, and the pore volume of the ZIF. Dozens (at least 10⁵) unique ZIF species or structures are known, each having a different chemical structure based on the type of transition metal and linker (or multiple linkers) constituting the structure. Each topology is identified using a unique ZIF name, e.g., ZIF-1 to ZIF-10⁵. For a description of ZIFs, including the specific chemical compositions and associated properties of numerous known ZIF species, see Phan et al., "Synthesis, Structure, and Carbon Dioxide Capture Properties of Zeolitic Imidazolate Frameworks," Accounts of Chemical Research, 2010, 43(1), pp. 58-67 (received April 6, 2009).

[0032] Some examples of carbon adsorption materials include carbon formed by the thermal decomposition of synthetic hydrocarbon resins such as polyacrylonitrile and sulfonated polystyrene-divinylbenzene; cellulose char; charcoal; and activated carbon formed from natural source materials such as coconut shells, pitch, wood, petroleum, and coal.

[0033] Adsorbent particles can have properties such as particle size, pore size, and pore volume, which may depend on the type of adsorbent. These properties of adsorbent particles in a composite adsorption medium can be selected based on the specific type of gas in the gas mixture to be adsorbed by the adsorbent particles.

[0034] Generally, the useful or preferred particle size for preparing composite adsorbents using the additive manufacturing techniques described herein may range from 2 microns to 20 microns, although larger or smaller adsorbent particles may also be useful. The particle size of the adsorbent particles can be measured by known techniques, including sieving techniques.

[0035] In some embodiments, the composite adsorbent media disclosed herein comprises a first adsorbent particle whose volume or weight can vary from greater than 0% to less than 100% in the composite adsorbent media, and a second adsorbent particle whose volume or weight can vary from greater than 0% to less than 100% in the composite adsorbent media. Thus, the composite adsorbent media may have the same or different weight or volume percentages of the first and second adsorbent particles.

[0036] A binder useful for a composite adsorption medium can be any material that can be combined with two or more different types of adsorbent particles and solidified to form a composite as described. Examples include organic materials such as polymers (e.g., synthetic polymers or natural polymers, both of which may be optionally chemically curable), inorganic materials such as clay and other inorganic particles, and dissipative materials.

[0037] Composite adsorption media can be useful for separating gases contained in gas mixtures. Gas mixtures typically may contain a high-value reagent gas and one, two, or more other gases distinct from the reagent gas.

[0038] According to some exemplary uses, composite adsorption media can be useful for purifying reagent gases in gas mixtures by adsorbing multiple different impurity gases from a gas mixture containing a reagent gas in a purified form (optionally combined with an inert stabilizing gas or diluent) along with two different impurities at concentrations typical of impurities. The composite adsorption media can be used effectively as a filter by passing the gas mixture through it. The gas mixture comes into contact with the composite adsorption media, and the impurities are adsorbed onto the media, while the reagent gas is not adsorbed and passes through the media with a reduced amount of impurities. In use, containers containing reagent gases containing impurities deliver the reagent gas as a gaseous raw material to process equipment that uses the reagent gas as a raw material, for example, to tools for processing or manufacturing semiconductor wafers or microelectronic devices. Non-limiting examples include, for example, ion implantation tools and deposition tools for chemical vapor deposition (including variations such as plasma-assisted chemical vapor deposition), physical vapor deposition (e.g., sputtering), atomic layer deposition, etc.

[0039] A specific example of this application is shown in Figure 1. In this example, for instance, when the gas is delivered from a storage container for use in the manufacturing process, a composite adsorption medium can be used to further purify the storage raw material gas, which has already been purified at the time of use, immediately before or shortly before the reagent gas is supplied to the manufacturing process.

[0040] As shown in the figure, the storage container 2 contains a highly purified, optionally concentrated form of reagent gas 4. The reagent gas 4 is highly purified and may have a purity of, for example, greater than 99, 99.9, or 99.99%. In some processes, the reagent gas may be diluted with an inert stabilizing gas such as helium, nitrogen, hydrogen, or argon, and the inert gas may be present at concentrations greater than 10, 50, or 70%. The reagent gas contains two or more known impurities, each distinct from the reagent gas and any stabilizing gas. Each of the two impurities is present at concentrations typical for the impurity, for example, less than 0.1, 0.01, or 0.001%, or at lower concentrations on a volume basis, for example, in the range of parts per million (ppm) or parts per billion (ppm) based on the total volume of the gas mixture.

[0041] Any of the impurities may be of a type initially present in the reagent gas, the storage container, or the adsorbent contained in the storage container at the time the reagent gas is added to the storage container (e.g., atmospheric impurities such as nitrogen (N2), oxygen (O2), methane (CH4), water vapor (H2O), carbon dioxide (CO2), hydrogen (H2), or carbon monoxide (CO)). During the storage of the reagent gas, other types of impurities may be generated in the storage container during the time after the reagent gas has been filled into the storage container. This can occur, for example, by the chemical modification or decomposition of the reagent gas into derivatives of the reagent gas that are impurities. Further sources of impurities may be generated during the storage of the reagent gas through chemical interactions between the reagent gas and other materials contained in the storage container, such as an inert gas, the material of the storage container sidewalls, different impurities, or the material of the adsorbent.

[0042] Container 2 may be any useful storage container adapted for use in containing, storing, or transporting reagent gas 4 under high pressure, low pressure, or near-atmospheric pressure storage conditions. Container 2 may have an internal volume for containing reagent gas and may contain an adsorbent for storing the reagent gas, or it may be a high-pressure container without an adsorbent. A valve or other dispensing mechanism is positioned at the opening of the container to allow the reagent gas to be added to the internal volume and subsequently dispensed from the internal volume. The container may be filled in its initial location, transported to a place of use (e.g., a cleanroom), and held at the place of use to supply the reagent gas to a processing tool 10 containing a semiconductor wafer 12, for example, a tool for processing or manufacturing semiconductor wafers or microelectronic devices.

[0043] According to these systems and methods, the reagent gas 4 is dispensed from a container 2, passes through a conduit, and reaches a housing 6 containing a composite adsorption medium 8. The composite adsorption medium 8 contains two different types of adsorbents. One adsorbent is effective in adsorbing a certain amount of the first of two impurities, which is at least a portion of the first impurity (e.g., at least 50%), preferably a substantial amount or substantially all of the first impurity (e.g., at least 75, 90, or 95%). The second adsorbent is effective in adsorbing a certain amount of the second of the two impurities, which is at least a portion of the second impurity (e.g., at least 50%), preferably a substantial amount or substantially all of the second impurity (e.g., at least 75, 90, or 95%). The composite adsorption medium 8 does not contain any adsorbent that adsorbs a significant amount of the reagent gas; for example, the composite adsorption medium 8 adsorbs less than 10, 5, 2, or 1% of the reagent gas.

[0044] As the reagent gas 4 passes through the composite adsorption medium 8, most of the first and second impurities are adsorbed onto the composite adsorption medium 8. The reagent gas containing the reduced amount of impurities then passes through the housing 6 and is delivered to the processing tool 10, for example, through a second conduit. Other flow control devices such as flow meters, pressure valves, pressure regulators, and pressure and temperature sensors may be included in the system but are not shown.

[0045] According to different exemplary uses, composite adsorbents may be useful as adsorbents in storage containers used to contain, store, transport, and dispense high-purity reagent gases into manufacturing processes. Composite adsorbents are contained in storage containers of a type used for storing, transporting, and delivering high-purity reagent gases into manufacturing processes, typically metal cylinders. The storage container may be any useful storage container adapted to contain, store, transport, or dispense reagent gases, and to store adsorbent reagent gases on the adsorbent material within the container. The storage container may be adapted to contain reagent gases for transporting the gas, or it may receive reagent gases and be connected to manufacturing tools to separate the reagent gases from impurities or stabilizing gases stored and transported with them.

[0046] The reagent gas may be contained in a container under high pressure, low pressure, or near-atmospheric pressure storage conditions. A valve or other dispensing device is positioned at the opening of the container to allow the reagent gas to be added to the inside of the container and selectively dispensed from the internal volume.

[0047] According to a specific method, the container is filled with reagent gas at a first location (e.g., the site of reagent gas production or processing) and transported to a point of use (e.g., within a cleanroom). At the time of use, the container is connected to a processing system that uses reagent gas as a gaseous raw material, such as a tool for processing or manufacturing semiconductor wafers or microelectronic devices. Non-limiting examples include ion implantation tools and deposition tools for chemical vapor deposition (including variations such as plasma-assisted chemical vapor deposition), physical vapor deposition (e.g., sputtering), atomic layer deposition, etc.

[0048] In this application, the composite adsorbent medium is used as an "in-situ" storage and purification medium. The composite adsorbent medium contains at least two different types of adsorbents. The first adsorbent is effective in adsorbing and then selectively desorbing high-value reagent gases. The second adsorbent is effective in adsorbing impurities, but does not desorb impurities under conditions that would effectively desorb the reagent gas. A system containing the composite adsorbent medium in a storage container can be used to purify reagent gases contained and stored in a storage container by the composite adsorbent medium adsorbing and retaining the amount of impurities that may be present in the reagent gas when the reagent gas is added to the storage container.

[0049] More specifically, the reagent gas can be added to the container in a form that is highly purified and selectively concentrated (e.g., free of stabilizing gases), but is known to contain at least one impurity gas (different from the reagent gas and any stabilizing gases). The impurity may be present in amounts typical to the amount of impurity, for example, at concentrations less than 0.1, 0.01, or 0.001%, or at concentrations lower than that on a volume basis, for example, in the range of parts per million (ppm) or parts per billion (ppm) based on the total volume of the gas mixture.

[0050] To store and purify reagent gases, reagent gases containing impurities (considered to be a mixture of reagent gases and impurities) are added to a container housing a composite adsorption medium. The reagent gas containing impurities comes into contact with the composite adsorption medium, and both the reagent gas and the impurity gas are adsorbed onto the adsorption medium, each being adsorbed by different adsorption materials. After the reagent gas and impurity gas are effectively adsorbed onto the adsorption medium, the reagent gas can be desorbed from the adsorption medium under conditions that do not cause desorption of impurity gases, for example, under conditions that do not cause desorption of impurity gases, or under conditions that cause small or slight desorption of impurity gases, for example, less than 20, 10, or 5% of the total amount of adsorbed impurity gas may be desorbed. Through these steps, the adsorbed and desorbed reagent gas can be further purified, for example, by removing impurity gases that are adsorbed and not desorbed by the desorption of the reagent gas, at least largely. The desorbed reagent gas can be delivered to a processing device for use as a gaseous raw material.

[0051] A specific example of this application is shown in Figures 2A and 2B. In this example, impurities can be removed from the source gas using the composite adsorption medium when the gas is added to a storage container containing the composite adsorption medium, contained therein, and dispensed from there.

[0052] As shown in Figure 2A, the reagent gas 24 is stored in a container 20. Container 20 may be any container, for example, a bulk container of the type used to store large quantities of reagent gas as part of a reagent gas manufacturing or processing system. The reagent gas 24 may be in a substantially pure form, or optionally in a concentrated or diluted form (e.g., diluted with a stabilizing gas). The reagent gas 24 may have a purity of, for example, 90, 95, 99, 99.9, or greater than 99.99%. In some processes, the reagent gas may not be diluted (e.g., the reagent gas 24 contains at least 98 or 99% by volume of the reagent gas species), and in other processes, the reagent gas may be in a mixture with an inert stabilizing gas such as helium, nitrogen, hydrogen, or argon, and the stabilizing gas may be present in the gas mixture (reagent gas and stabilizing gas) at a concentration of 10, 50, or greater than 70% based on the total volume of the gas mixture. The reagent gas 24 contains at least one known impurity distinct from the reagent gas and any stabilizing gas. Impurities are present at concentrations typical of impurities, for example, less than 1, 0.1, 0.01, or 0.001%, or at lower concentrations on a volume basis, for example, in the range of parts per million (ppm) or parts per billion (ppm) based on the total volume of the gas mixture.

[0053] Impurities may be of the type present in the reagent gas as a product of a process that generates the reagent gas (e.g., a reaction process) or a process that processes the reagent gas after it has been generated (e.g., atmospheric impurities such as nitrogen (N2), oxygen (O2), methane (CH4), water vapor (H2O), carbon dioxide (CO2), hydrogen (H2), or carbon monoxide (CO)). Impurities may also be contaminants from the container or any associated flow control equipment. Alternatively, impurities may be generated within the container during storage of the reagent gas, during the time after the reagent gas has been filled into the container or processed within the container. This can occur, for example, by the chemical modification or decomposition of the reagent gas into derivatives of the reagent gas that are impurities. Another source of impurities may be the generation of impurities within the container through chemical interactions between the reagent gas and other materials contained within the container, such as an inert gas, materials of the container sidewall or flow equipment, or other impurities.

[0054] Container 20 may be any useful container adapted for use in storing reagent gas 24 under high pressure, low pressure, or near-atmospheric pressure storage conditions. Container 24 may have an internal volume for storing reagent gas and may contain an adsorbent (not shown) for storing the reagent gas, or it may be a high-pressure container without an adsorbent. Container 24 may be adapted to hold reagent gas in bulk and may include valves and flow control units (not specifically shown) for dispensing reagent gas into a single storage cylinder. Optionally, the container may be connected to a configuration of multiple flow control conduits and valves (e.g., multiple "inlets") for dispensing reagent gas in parallel into multiple storage cylinders.

[0055] According to these systems and methods, the reagent gas 24 is dispensed from a container 20 and passes through a conduit to a storage container 26 containing a composite adsorption medium 28. The container 26 has volume and performance requirements to enable the container to safely contain, store, and transport the reagent gas from the location of the container 20 to the point of use of the reagent gas. The composite adsorption medium 28 contains two different types of adsorbents inside the container 26. One adsorbent is effective in adsorbing a certain amount of reagent gas species. The second adsorbent is effective in adsorbing a certain amount of known impurities, the amount of which is at least a portion of the impurities (e.g., at least 50%), preferably a substantial amount or substantially all of the impurities (e.g., at least 75, 90, or 95%).

[0056] As shown in Figure 2A, the reagent gas 24 is added to the container 26 and brought into contact with the adsorption medium 28, thereby adsorbing both the reagent gas species and the impurities contained in the reagent gas onto the composite adsorption medium 28. Next, as shown in Figure 2B, the container 26 is transported to a place of use such as a clean room.

[0057] The container 26 is connected to the processing tool 30, and the adsorbed reagent gas 24 is desorbed from the composite adsorption medium 28. The desorption conditions are effective in causing the desorption of a considerable amount of the adsorbed reagent gas species, but most or substantially all of the impurities remain adsorbed (e.g., at least 50, 70, or 90% of the adsorbed impurities remain adsorbed). The desorbed reagent gas, now containing the reduced amount of impurities, passes from the container 26 and is delivered to the processing tool 30, for example, through a second conduit, for processing of the substrate (e.g., semiconductor wafer or microelectronic device) 32. Other flow control devices such as flow meters, pressure valves, pressure regulators, and pressure and temperature sensors may be included in the system but are not shown.

[0058] In a variation of this method, the bulk container may be a storage and transport container containing a reagent gas, at least one impurity, and a high level (e.g., at least 20, 40, or 60%) of inert gas to stabilize the reagent gas during transport. The bulk container may or may not contain an adsorbent. The bulk container delivers the reagent gas and stabilizing gas to a smaller container that adsorbs the stabilizing gas and at least one impurity, does not adsorb the reagent gas, and then delivers the reagent gas to a manufacturing tool. The smaller container, for example, a ballast cylinder adapted for short-term storage of the reagent gas before delivery to a manufacturing tool, contains the adsorbent of this specification containing a composite adsorbent medium as described. The two types of adsorbents contained in the ballast cylinder are effective in adsorbing the inert gas and at least one impurity. The adsorbent substantially does not adsorb the reagent gas, and the reagent gas can pass through the adsorbent and container or remain in the upper space within the container as the non-reagent gas is adsorbed, after which the reagent gas can be dispensed from the ballast cylinder.

[0059] The gas mixture can be flowed from a bulk container into a ballast cylinder. In the ballast cylinder, the stabilizing gas and impurities are adsorbed onto a composite adsorption medium. The reagent gas is not adsorbed and remains in a gaseous state, for example, in the upper space of the ballast cylinder. In this gaseous state, the reagent gas can be delivered from the ballast cylinder to the manufacturing tool (without desorption of the adsorbed stabilizing gas and impurities) in a form containing a reduced concentration of stabilizing gas (e.g., less than 20, 40, or 60% stabilizing gas).

[0060] In yet another exemplary use, a composite adsorbent medium may be useful for separating or concentrating a certain amount of reagent gas contained in a gas mixture that includes a reagent gas and one or more non-reagent gases (e.g., a second gas, a third gas) that are present in a substantial amount (more than the amount of impurities) in the gas mixture containing the reagent gas, or in the amount of impurities.

[0061] The gas mixture may be any gas mixture containing a significant amount of reagent gas species but not a purified amount. The gas mixture may be a mixture of gases from any source, one example being exhaust gas from a process that uses reagent gases as a raw material. The process does not use the reagent gases 100% efficiently, resulting in a stream of exhaust gas from the process containing a significant amount of unused reagent gas. The exhaust gas may contain, on a volume basis, at least 5 and up to 50 or 60% of unused reagent gas species, e.g., 10 to 40% unused reagent gas, based on the total volume of the exhaust gas. The exhaust gas may also contain a mixture of other non-reagent gases in concentrations of impurities (e.g., less than 0.1, 0.01, or 0.01%, or in concentrations in the range of ppm or ppb), or in concentrations higher than 1 to 40, 50, or 60% on a volume basis, e.g., based on the total volume of the exhaust gas. Examples of non-reagent gases that may be present in the exhaust gas mixture as impurities or at higher concentrations include hydrogen, nitrogen, helium, xenon, and argon, which can be selectively removed from the exhaust gas flow by adsorption onto composite adsorbent materials.

[0062] The exhaust gas mixture flows from a process facility that uses reagent gases as raw materials and is brought into contact with the composite adsorption medium described herein. The composite adsorption medium adsorbs at least two different types of gases in the exhaust gas.

[0063] In one version of this method, the composite adsorbent medium can adsorb two or more different types of non-reagent gases. The composite adsorbent medium does not adsorb reagent gases, which either pass through the adsorbent medium with a reduced concentration of non-reagent gases and a higher concentration of reagent gases, or remain in the upper space of the container and can then be removed. The amount of non-reagent gases adsorbed can be any amount useful for increasing the concentration of reagent gases in the exhaust gas. In the exemplary method, the amount of any or both of the non-reagent gases adsorbed by the composite adsorbent medium may be at least a portion of the non-reagent gases (e.g., at least 50%), preferably a substantial amount or substantially all (e.g., at least 75, 90, or 95%) of the non-reagent gases contained in the exhaust gas mixture. By using the composite adsorbent medium effectively in this way as a flow-through filter, non-reagent gases in the exhaust gas mixture can be separated and removed from the reagent gases that pass through the composite adsorbent medium without being adsorbed on it, at least in proportion to the reagent gases that pass through the composite adsorbent medium.

[0064] According to a different version of this method, the composite adsorption medium can adsorb one or more reagent gases and non-reagent gases, each adsorbed by a different adsorption material. Other non-reagent gases may not be adsorbed. After the reagent gas and one or more non-reagent gases have been effectively adsorbed onto the adsorption medium, the reagent gas can be desorbed from the adsorption medium under conditions that do not cause desorption of one or more non-reagent gases, for example, under conditions that do not cause desorption of non-reagent gases, or under conditions that cause small or slight desorption of non-reagent gases, for example, less than 20, 10, or 5% of the adsorbed non-reagent gases may be desorbed. These steps allow the adsorbed and desorbed reagent gases to be separated, at least largely, from the non-reagent gases in the exhaust gas mixture.

[0065] As shown in Figure 3, a tool 40 containing a substrate (semiconductor wafer or microelectronic device) 42 uses reagent gas 46 as a gaseous raw material. Not all of the reagent gas is used during the process performed by the tool 40; for example, less than 60, 50, 40, or 30% of the reagent gas delivered to the process may be effectively consumed by the process. Other gases may also be present or generated by the process. As a result, an exhaust gas mixture 44 is produced exiting the tool 40. The exhaust gas mixture contains a considerable amount of high-value reagent gas, for example, at least 5 by volume based on the total volume of the exhaust gas, and up to 50 or 60% of unused reagent gas species, for example, 10 to 40% unused reagent gas. Depending on the cost of the reagent gas, recovering even a portion of the reagent gas from the exhaust gas for reuse can achieve both waste reduction and cost reduction through the reuse of high-value (high-cost) reagent gases.

[0066] One version using the system in Figure 3 involves the use of a composite adsorption medium as a flow-through filter to remove non-reagent gases from the exhaust flow by adsorption, while reagent gases are not adsorbed but pass through the medium. In this version, the exhaust gas mixture 44 flows into a housing 50 containing a composite adsorption medium 52 effective for adsorbing two or more different types of non-reagent gases in the exhaust gas mixture 44. The composite adsorption medium does not adsorb reagent gases, and the reagent gases pass through the adsorption medium as a concentrated reagent gas 48 with less non-reagent gas and a higher concentration of reagent gas. At least a portion of the two different non-reagent gases, for example, at least 50% of each of the two non-reagent gases, preferably a substantial amount or substantially all of them, such as at least 75, 90, or 95% of each of the two non-reagent gases contained in the exhaust gas mixture, is adsorbed onto the composite adsorption medium 52. The adsorbent adsorbs small or negligible amounts of reagent gas, for example, less than 10, 5, 2, or 1% of the total amount of reagent gas in the exhaust gas mixture 44.

[0067] According to a different version using the system in Figure 3, the composite adsorbent medium 52 adsorbs reagent gas species that are part of the exhaust gas mixture 44. The second adsorbent is effective in adsorbing one or more amounts of non-reagent gases. The reagent gas species adsorbed by the composite adsorbent medium may be at least a portion of the reagent gases, for example, at least 50% of the amount of reagent gases present in the exhaust gas mixture 44. Preferably, the composite adsorbent medium can adsorb a substantial amount or substantially all of the amount of reagent gases present in the exhaust gas mixture 44, for example, at least 75, 90, or 95% of the total amount of reagent gases present in the exhaust gas mixture 44.

[0068] After the reagent gas and at least one non-reagent gas have been effectively adsorbed onto the adsorption medium, the reagent gas can be desorbed from the adsorption medium 52 under conditions that do not cause desorption of at least one non-reagent gas, for example, under conditions that do not cause desorption of the non-reagent gas, or under conditions that cause small or slight desorption of the non-reagent gas, for example, less than 20, 10, or 5% of the total amount of adsorbed non-reagent gas may be desorbed.

[0069] Other flow control devices, such as flow meters, pressure valves, pressure regulators, and pressure and temperature sensors, may be included in the system shown in Figure 3, but are not shown.

[0070] The composite adsorbent media described herein can be prepared by additive manufacturing methods, including methods commonly referred to as “3D printing” techniques. A variety of different additive manufacturing techniques are known. Specific examples include what is commonly called “powder bed” additive manufacturing methods, which include various “binder jet printing” techniques. Other examples include stereolithography (SLS) and “feedstock dispensing methods” (FDM). While composite adsorbent media and related methods and materials are described herein in relation to these exemplary types, the preparation and use of the described composite adsorbent media can also be achieved by other methods.

[0071] An exemplary method for preparing the described composite adsorbent media includes an additive manufacturing step of sequentially forming multiple layers (e.g., “pathways”) of a solidified feed material composition containing at least two different types of adsorbent particles dispersed in a solidified binder composition, the solidified binder composition acting as a structure that holds the adsorbent particles together in the solidified feed material composition. Using a series of additive manufacturing steps, the multiple layers of the solidified feed material are sequentially formed into a multilayer composite adsorbent media made from the layers of the solidified feed material.

[0072] A multilayer composite adsorbent medium (or "composite adsorbent medium" or simply "composite material") contains two different types of adsorbent particles, each adapted to adsorb the gaseous components of a gas mixture. One of the two different adsorbents may be effective in adsorbing reagent gases, and the other may be effective in adsorbing non-reagent gases, which may be impurities. Alternatively, the first adsorbent may be effective in adsorbing non-reagent gases such as impurities, and the second adsorbent may be effective in adsorbing different non-reagent gases such as different impurities, and neither adsorbent effectively adsorbs the reagent gas, for example, the composite adsorbent medium adsorbs less than 5%, 2%, or 1% of the reagent gas in contact with the adsorbent medium.

[0073] As raw materials, adsorbent particles are in particulate form, such as powder, and exhibit desired adsorption and desorption functionality. However, in the form of a composite adsorbent medium, the adsorbent particles are combined with other materials. The multilayer composite adsorbent medium that initially arises from an additive manufacturing process is a structure sometimes commonly referred to as a "green body." Multilayer composite adsorbent mediums in the form of a green body contain materials that are useful or required for the additive manufacturing process, such as various components of a binder composition. Some materials of the composite adsorbent medium that were used to prepare the composite adsorbent medium but are unnecessary as adsorbent materials for the desired functionality of the contained adsorbent particles may be removed from the green body, or processed in other ways to further solidify or harden them. By removing or processing these materials from the green body, the functionality of two or more adsorbent particles as adsorbent materials for use in the described methods and systems is improved.

[0074] Therefore, the composite adsorbent initially formed by additive manufacturing techniques can be further processed to remove solidified binder compositions, to improve the mechanical properties of the multilayer composite adsorbent, or both. In exemplary processes for processing a multilayer composite adsorbent, the composite may be treated by one or more of the following: a debinding process (to remove solidified binder or a portion thereof), contact with a solvent, contact with a gas (e.g., for gas etching), or exposure of the composite to high temperatures to solidify, cure, or sinter the binder or composite.

[0075] Certain types of additive manufacturing methods have been found useful or advantageous for preparing the described multilayer composite adsorption media. Generally, additive manufacturing processes are known to be useful for preparing structures exhibiting a wide range of shapes and sizes. Additive manufacturing can also enable the printing of complex microstructures that potentially have fine channels for enhanced gas permeability with controlled pressure drops. Additive manufacturing processes can also be highly automated, relatively efficient, and cost-effective.

[0076] Furthermore, certain types of addition methods may be effective in producing multilayer composite adsorbent media that retain the useful functionality (e.g., as an adsorbent) of temperature-sensitive adsorbents such as MOF particles. By exemplary addition methods, MOF adsorbents can be included as adsorbents in composite adsorbent media without the MOF being physically altered or "modified" during the addition process, and preferably, the MOF adsorbent, if present, can retain its original physical (chemical, molecular) form, which allows the MOF to reversibly adsorb and desorb reagent gases, non-reagent gases, or impurities.

[0077] To prevent the degradation of MOF adsorbent particles, that is, to prevent physical, chemical, or molecular alteration of the MOF molecules contained in the MOF adsorbent particles and the loss of the desired functionality of the MOF particles, a preferred step in preparing the multilayer composite by additive manufacturing technology may include a step of avoiding exposure of the MOF particles to temperatures above 300 degrees Celsius, and preferably, the MOF particles may not be exposed to temperatures above 250 degrees Celsius or 200 degrees Celsius. It may also be desirable to prevent or minimize the exposure of the MOF adsorbent particles to indoor air and moisture during the additive manufacturing process.

[0078] Additive manufacturing processes for forming multilayer composite adsorbent media require components comprising at least two different types of adsorbent particles and one or more components that are combined to form a binder composition. The binder composition may be combined with the adsorbent particles, or the binder composition may be solidified (hardened, cured, etc.) to produce a solidified feedstock composition containing the solidified binder composition that acts as a physical support structure (matrix) for the adsorbent particles. The steps of combining two or more adsorbent particles with the binder composition and solidifying the binder composition as a layer of the composite adsorbent media may differ depending on the type of additive manufacturing technique. For example, the step of combining adsorbent particles with the binder composition may differ with respect to powder bed technology and different versions of powder bed technology compared to stereolithography and feedstock dispensing methods. The components of the binder composition may also differ depending on the type of additive manufacturing technique.

[0079] In general, useful binders may include any material that can solidify as part of the feedstock composition or by being added to the feedstock layer, thereby selectively forming solidified feedstock in a portion of the feedstock layer. Examples include organic materials such as polymers (e.g., synthetic or natural polymers, both of which may be optionally chemically curable), inorganic materials such as clay and other inorganic particles, and dissipative materials.

[0080] An example of a type of material that may be useful as a binder composition ("binder") or its components is nonpolymer inorganic particles, such as clay particles, which can be suspended in a liquid and dried by removal of the liquid to form a solid material. Useful clay or other inorganic particle-type binder components can be combined with two or more different types of adsorbent particles and any polymer so that the inorganic particles and adsorbent particles are suspended together in a liquid (e.g., water, an organic solvent, or a combination of both), and then the liquid can be removed, for example, by evaporation. Upon removal of the liquid, the inorganic particles become part of a solidified binder composition that supports the adsorbent particles as part of a solidified feedstock composition.

[0081] Other binder compositions include curable polymer binder materials. Curable polymer binders in liquid form can be combined with adsorbent particles in any manner. The feed material layer may be formed from a liquid polymer binder and adsorbent particles, and the binder is combined with the adsorbent particles before or during the formation of the feed material layer. The curable polymer binder contained in the feed material layer can be solidified. Examples of liquid binder materials include thermoplastic polymers that can be reversibly heated to form a liquid and then cooled to form a solid (e.g., reversibly melted and solidified). Alternatively or additionally, liquid polymer binder materials may be chemically curable, for example, by exposure to high temperatures (thermosetting) or by exposure to electromagnetic radiation from a laser, such as a UV laser.

[0082] Other examples of polymer binders may be in liquid form containing a liquid solvent. The binder may be combined with adsorbent particles and, if desired, applied to form a feed material layer, after which the solvent may be evaporated, leaving the polymer binder as a structure supporting the adsorbent particles. The polymer may optionally be cured thereafter by heat (high temperature), exposure to radiation, or by a chemical reaction initiated by another reaction mechanism.

[0083] The curable liquid binder composition may contain curable materials such as chemical monomers, oligomers, polymers, and crosslinking agents, and may further contain small amounts of functional components or additives that enable or accelerate the flow or curing of the curable binder composition. These may include any of the following: flow aids, surfactants, emulsifiers, dispersants to prevent particle aggregation, and initiators to initiate the curing of polymers when exposed to electromagnetic (e.g., ultraviolet) radiation or high temperatures.

[0084] In additive manufacturing techniques known as "powder bed" techniques, which include various techniques known as "binder-jet printing" techniques, adsorbent particles are contained in a bed of "supply material" that can be formed into a uniform layer known as the "supply material layer." The supply material or supply material layer contains one or more or two or more different types of adsorbent particles and may optionally contain one or more additional components, such as one or more components of a binder composition. In some embodiments, the same supply material is used to form the supply material layer and may contain both a first adsorbent medium particle and a second adsorbent medium particle. In other embodiments, multiple supply materials are used, for example, the first supply material may have a first adsorbent medium and the second supply material may have a second adsorbent medium different from the first adsorbent medium. In such cases, a first feed material layer can be formed on the surface from the first feed material, the first feed material layer can be solidified, and then a second feed material layer can be formed on the first feed material layer from the second feed material, and then the second feed material layer can be solidified, thereby creating a composite adsorbent medium having alternating layers having different adsorbent media. In such embodiments, the feed material for the first feed material layer may include one (but not both) of the first adsorbent medium particles and the second adsorbent medium particles, and the feed material for the second feed material layer may include the other of the first adsorbent medium particles and the second adsorbent medium particles. An exemplary binder may include a first binder component as part of the feed material and a second binder component which is a liquid component that is part of a liquid selectively dispensed onto the feed material layer. As a binder component that is part of the dried feed material powder, the amount of binder contained in the feed material powder may be, for example, at least 20% or at least 30% on a volume basis of the total volume of the feed material, if it is formed as a feed material layer (this volume percentage is a “bulk” volume percentage based on the total volume of the feed material material including void space; i.e., the volume of binder per unit of the total volume of the feed material layer including void space).

[0085] These methods solidify a binder composition in which one or more components are included in the feedstock layer or can be selectively applied to a portion of the feedstock layer, thereby forming a solidified binder composition in the selected portion (region) of the feedstock layer. The mechanisms by which the binder composition (or a separate portion thereof) becomes located in the selected portion of the feedstock layer, and the mechanisms by which the binder composition in the selected portion of the feedstock layer becomes solidified, may vary.

[0086] Powder bed additive manufacturing technology can generally involve a sequence of multiple individual layer formation steps, each used to form a single cross-sectional layer of a multilayer composite adsorbent medium. After forming the first (bottom) layer, each subsequent layer is formed on the upper surface of the preceding layer. This series of multiple individual layer formation steps is effective in forming a multilayer composite adsorbent medium of multiple individually formed layers from a solidified feedstock.

[0087] These technologies, like other additive manufacturing technologies, produce objects described or defined by digital data such as CAD (computer-aided design) files. A three-dimensional object is constructed layer by layer using a series of individual steps combined to produce a composite ("multilayer composite adsorbent medium") made of many thin cross-sectional layers of solidified feed material. Each layer-forming step may include forming a single feed material layer on a surface containing feed material with two different types of adsorbent particles. In some exemplary methods, the feed material layer may contain a binder composition or its components. In other exemplary methods, the feed material layer does not contain a binder composition or its components, and in these methods, the binder composition is selectively added to a portion of the feed material layer.

[0088] In one example, a roller or other dispensing device uniformly applies a certain amount of a feeder composition in powder form onto a surface by applying a single amount of the powder feeder composition in a single pass, or by applying multiple distinct amounts of the powder feeder onto the surface in multiple passes. The "feeder layer" may be formed from the feeder composition by one or more steps of applying the powder feeder composition to a surface and using a roller or other application method to form a smooth, uniform feeder layer having a desired useful depth.

[0089] The useful depth (thickness) of the feed material layer may depend on various factors such as the particle size of the adsorbent particles in the feed material layer, the desired properties of the solidified feed material layer (quality, e.g., surface finish, layer density, dimensional accuracy), and the resolution of the print head or other device used to apply the liquid material to the feed material layer. Preferably, the thickness of the feed material layer may be at least two or three times the diameter (D50) of the largest adsorbent particles in the feed material. A typical useful thickness of the feed material layer may range from 25 microns to 200 microns.

[0090] After forming a feed material layer, a portion of the feed material layer is selectively processed to form a solidified feed material layer. Following these steps to form a solidified feed material composition, an additional thin layer of powder feed material composition is spread over the top surface of the completed layer, which contains solidified feed material surrounded by a certain amount of unsolidified (original) feed material composition.

[0091] The process is repeated to form multiple layers containing solidified feedstock, with each new layer of solidified feedstock (after the first layer) forming on and adhering to the previous layer of solidified feedstock. Multiple feedstock layers are deposited to form a multilayer composite adsorbent medium, with multiple layers of solidified feedstock formed one after another on each completed layer. After all layers of the multilayer composite adsorbent medium have been deposited, portions of the feedstock layers containing the original feedstock material not used to prepare the solidified feedstock may be separated from the multilayer composite adsorbent medium.

[0092] If desired or useful, the feed material layer used in powder bed additive manufacturing technology may contain one or more optional components that are part of the binder composition or otherwise useful as part of the solidified feed material layer. These may include, for example, flow aids to improve the flow of the feed material in the printer bed and improve the ability of the feed material to form a uniform (uniform, of the same height, homogeneous) feed material layer. Alternatively or additionally, the feed material layer may optionally contain a solid polymer material that acts as a spacer between adsorbent particles, for example, as a “pore-forming” material. Such a solid polymer may be a thermoplastic (solid in form at room temperature) pore-forming polymer and may be present in the feed material layer in any desired amount, for example, 0.5 to 15% by weight based on the total weight of the feed material, for example, 1 to 12 or 2 to 10% by weight based on the total weight of the feed material.

[0093] More specifically, one concrete example of powder bed technology is called "jet binder printing." In these methods, the feed material layer contains two or more different types of adsorbent particles and may or may not contain a binder composition or components of a binder composition.

[0094] A solidified feedstock layer is formed by selectively applying a liquid material (considered to be a binder or binder component) to a portion of the feedstock layer, thereby selectively forming a solidified feedstock composition in those selected portions of the feedstock layer. A printhead or other device effective for selectively dispensing and applying a desired amount of liquid to a portion of the feedstock layer moves over the upper surface of the feedstock layer. The printhead or other useful device discharges the liquid and applies it to the selected portion of the upper surface of the feedstock layer. The liquid flows into the feedstock layer and is useful for forming a solidified binder composition at the location in the feedstock layer where the liquid is selectively applied. The solidified feedstock composition contains adsorbent particles dispersed throughout the solidified binder composition. The portions of the feedstock layer that have not come into contact with the liquid remain as unsolidified feedstock and can subsequently be separated from the solidified feedstock composition.

[0095] Within this general description of jet binder technology, different variations also exist. According to one variation, the feed material layer contains a dry powder feed material composition containing adsorbent particles and a binder composition or a portion of a binder composition, and the liquid selectively applied to the feed material layer is a liquid useful for the process of solidifying the binder composition or its components within the feed material layer. In more exemplary detail, but without limiting this specification, this type of method can use a dry (powder) feed material containing adsorbent particles and components of a binder composition that dissolve, suspend, or otherwise activate and solidify when in contact with the discharged liquid, and the combined binder composition can then solidify as a matrix surrounding the adsorbent particles.

[0096] The components of the binder composition contained in the feedstock may be organic, such as a polymer (e.g., polyvinyl alcohol) or a phenolic resin, or inorganic, such as inorganic particles, such as clay (e.g., bentonite clay). The liquid applied to the feedstock layer may be a liquid effective in dissolving, dispersing, chemically reacting with, or otherwise solidifying the binder composition or binder components initially present in the feedstock layer. In some examples, the liquid or a portion of the liquid may then be removed (e.g., evaporated) to leave a solidified feedstock composition containing the binder composition solidified as a matrix structure surrounding and supporting adsorbent particles.

[0097] In certain jet binder printing systems, the feedstock may be in the form of a dry powder containing two different types of adsorbent particles (e.g., a combination of at least two of zeolite, MOF, or carbon adsorbent particles) and a binder in the form of inorganic particles such as clay (e.g., bentonite clay). The clay may be present in the feedstock in useful amounts, such as 3 to 20% by weight of clay, or 5 to 15% by weight of clay, based on the total weight of the feedstock. The clay binder can be solidified by contacting the clay binder with water, such as deionized water, which can be selectively applied to a portion of the feedstock layer using the print head or other dispensing device of the 3D printer. In this way, multiple layers of feedstock are sequentially formed by forming a feedstock layer and solidifying selected portions of the feedstock layer by contacting the feedstock layer with deionized water.

[0098] The resulting multilayer green body is produced, which is surrounded by loose (unsolidified) feedstock. Advantageously, by using water as the liquid to solidify the binder, the green body contains water as part of the binder to hold together the adsorbent particles of the solidified feedstock. For the process of separating the green body from the unsolidified powder feedstock, the water can be frozen to increase the strength of the green body.

[0099] In a specific example of a useful process, a multilayer green body can be formed from multiple layers of a feed material containing at least two different types of adsorbents and clay. The feed material may contain, contain, or consist of at least two different types of adsorbents and clay. The feed material may contain 5 to 20 wt% clay (e.g., bentonite clay), 80 to 95 wt% adsorbent particles (at least two different types), and less than 20, 10, or 5 wt% of any other material.

[0100] The feed material layer is formed from feed material powder, which selectively contacts water to solidify the clay, while a portion of the unsolidified feed material layer dries and remains in the form of loose feed material. After forming multiple layers of solidified feed material to produce a multilayer green body, the green body and the surrounding unsolidified feed material can be placed at a low temperature (e.g., -2°C to -10°C) to freeze the water contained in the green body. After the water has frozen, the green body can be mechanically separated from the surrounding loose forces, including optionally using a brush to remove powder particles from the surface of the frozen green body. Unused (unsolidified) feed material can be reused.

[0101] Next, the green body may be sintered. Preferably, after separating the green body from the unsolidified supply material, the green body is moved to the location where the sintering process will be performed, and the sintering process is immediately started at a temperature below 0 degrees Celsius or below -2 degrees Celsius while the green body remains frozen.

[0102] As a different variation of powder bed addition technology, the feed material layer does not contain (or requires) components that are part of the binder composition. In this variation, the liquid selectively applied to the feed material layer may contain all the necessary components of the binder composition, which may be in the form of a liquid thermoplastic or chemic curing polymer. In this variation, the liquid binder composition is selectively applied to the feed material layer and is made to solidify or be made to solidify at a given location to produce a solidified feed material layer.

[0103] In examples of this type of system, the feed material layer may contain adsorbent particles and does not need to contain other materials. For example, the feed material layer may contain two or more types of adsorbent particles in an amount of at least 70, 80, 90, or 95% by weight. However, other components in the feed material layer, such as pore-forming particles and flow aids, may be useful, as described herein.

[0104] The liquid binder composition applied to the feedstock layer may contain all the components of the binder composition necessary for selectively dispensing and applying the binder composition in liquid form to the feedstock layer, and for the liquid binder composition to solidify as part of the solidified feedstock layer. The liquid binder may contain a polymer material that can solidify by any of the following: a chemical curing mechanism (by exposure to electromagnetic radiation), by a decrease in temperature, or by removal of the solvent by evaporation. The liquid binder composition may contain a curable polymer in combination with useful amounts of additives such as an organic solvent, a fluidizer, or a surfactant, thereby giving the liquid binder flow and surface tension properties that enable the liquid binder to effectively interact with the particles of the feedstock layer to produce the desired solidified feedstock layer. Useful organic solvents, fluidizers, or surfactants may be selected based on the hydrophilicity or hydrophobicity of the particles of the feedstock.

[0105] Another variety of additive manufacturing techniques is called stereolithography. This method uses similar processes and equipment to powder bed technology. In these techniques, the feed material layer contains MOF particles dispersed in a curable liquid binder composition. The liquid feed material layer can be contained in a shallow bed, similar to binder jet technology. Multiple layers of the solidified feed material composition are formed sequentially by selectively curing (solidifying) each layer by exposure to electromagnetic radiation such as ultraviolet (UV) radiation. Compared to selectively applying liquid to the powder feed material layer to solidify the feed material layer (as described above with respect to jet binder technology), stereolithography technology selectively solidifies (hardens) those parts of the liquid feed material layer by exposing parts of the feed material layer to electromagnetic radiation, thereby inducing chemical curing.

[0106] Another additive manufacturing technique that may be useful as described herein is called “selective laser irradiation” or “SLI”. This process is similar to stereolithography, but instead of the liquid-curable feedstock used in stereolithography, the selective laser irradiation method uses a feedstock containing a solid material, such as a binder in powder form, in combination with adsorbent particles. The binder may be a thermoplastic polymer or a radiation-curable polymer. In the case of a thermopolymer, the binder can be heated and melted by the laser and then cooled and re-solidified as a feedstock. Alternatively, the solid (powder) binder contained in the feedstock may include a radiation-curable polymer that reacts and polymerizes when irradiated with a laser to form a solidified feedstock.

[0107] In addition to powder bed and stereolithography additive manufacturing techniques, other additive manufacturing techniques may also be useful for preparing multilayer adsorbent composition media, and may include non-powder bed techniques. One example is called "feed material dispensing method" (FDM). In this technique, the feed material layer is not prepared in the bed but is subsequently selectively solidified by selective contact with a liquid (by jet binder technique) or selective irradiation (stereolithography). Instead, a fluid (liquid) feed material containing both adsorbent particles and a binder composition is selectively applied to the surface as a pathway or layer, and multiple consecutive applications form a series of continuous layers of solidified feed material composition.

[0108] The feedstock may contain a binder as described herein, which may be a polymer (e.g., curable or thermoplastic), an inorganic material (e.g., inorganic particles), etc. If the binder contains a radiation-curable polymer, the feedstock may be solidified by exposing the binder to electromagnetic radiation. If the binder is inorganic, the feedstock may be solidified by exposure to high temperatures, for example, to remove the solvent.

[0109] For example, a feed material selectively applied to a surface by ejection via a printhead or other effective device contains all the components of a solidified feed material layer. The binder composition of a liquid feed material may contain a polymer material that can be solidified by a chemical curing mechanism, such as exposure to light or irradiation, exposure to high temperature, or by removal of the solvent from the liquid feed material. In another example, the binder composition of a liquid feed material may be a thermoplastic material that is heated above its melting temperature to form a feed material pathway or layer, and then cooled to produce a solidified feed material composition. An exemplary feed material composition may contain a binder component and a polymer, and is a fluid material that can be considered a semi-solid feed material or a viscous liquid.

[0110] Each of these different types of additive manufacturing techniques described herein for use in the preparation of multilayer composite adsorbents requires a binder composition, at least two different types of adsorbent particles (e.g., in the form of powder or aggregates of particles), and useful equipment for carrying out the additive manufacturing process. The equipment may be an automated 3D printer capable of forming the composite adsorbent by powder bed technology (generally), jet binder printing technology, stereolithography printing technology, filament deposition, or another useful additive manufacturing method. Useful equipment and associated methods are effective for sequentially arranging multiple layers of solidified feed material on top of preceding layers to form a multilayer composite adsorbent. Importantly, if the feed material contains MOF adsorbent particles, the method for preparing the multilayer composite adsorbent can be selected to avoid any treatment that would render the MOF adsorbent particles ineffective as an adsorbent material by physical or chemical alteration, such as exposure to high temperatures.

[0111] Examples of binder jet printing additive manufacturing techniques (100) useful for preparing multilayer composite adsorption media are shown in Figures 4A and 4B.

[0112] Figure 4A shows a series of steps for a useful binder jet printing additive manufacturing technique, identifying that the method can be used independently by different forms of feed material 102 filled into the printer bed of the additive manufacturing system and different liquids 104 filled into the print head of the additive manufacturing system.

[0113] The supply material 102 is a powder containing at least two different types of adsorbent particles and any additional components. In an exemplary method, the supply material 102 does not contain a binder composition or its components (for example, does not require a binder composition or its components), and the liquid 104 contains a binder composition. In another exemplary method, the supply material 102 contains a binder composition or components of a binder composition, and the liquid 104 contains a liquid component effective in solidifying the binder composition in the supply material.

[0114] The following describes a system and method for discharging a binder composition containing a curable polymer material or a binder component such as water from a printhead onto a selective portion of the feed material layer to bring about solidification of the selected portion of the feed material layer. This process can be carried out using a commercially available binder jet printing apparatus and a combination of two or more adsorbent particles described herein, with a liquid polymer binder or a binder component such as water (104) dispensed from the printhead of the apparatus.

[0115] According to an exemplary step of the method (Figure 4A), a dry (powder) feed material (102) is filled into the bed of a powder bed additive manufacturing system and formed as an even feed material layer of a desired depth on the build plate of the apparatus (110). In a subsequent step (112), a printhead selectively deposits a liquid binder or binder system component (104) onto a portion of the first layer. The liquid binder (104) may solidify after being placed on the feed material layer. For example, the liquid binder (104) may contain a polymer dissolved or dispersed in a liquid solvent that can be removed to solidify the polymer. Alternatively, the feed material may contain a binder component such as clay, and the liquid binder component (104), such as water (e.g., distilled water), may solidify the binder component of the feed material, e.g., clay.

[0116] After the liquid binder (104) is selectively applied to the feed material layer, the liquid binder (104) can be solidified, for example, by removing the solvent from the binder and applying heat to the liquid binder to form a solidified feed material in that portion. Alternatively, the liquid binder (104) may be a thermoplastic that can be melted, applied to the feed material layer, and then cooled to solidify. Alternatively, the liquid binder (104) may be a curable polymer that can be applied to the feed material layer in liquid form and then chemically react to solidify. Alternatively, the liquid may be a binder component (104) such as water that can be applied to the feed material layer and contains a second binder component such as inorganic particles, and the liquid and inorganic particles solidify to form a solidified feed material.

[0117] The liquid binder is applied to the feed material layer in an amount effective for fixing the position of the adsorbent particles in the feed material layer. While the method does not require the application of the liquid binder in an amount or manner that fills the spaces between the adsorbent particles in the feed material, it can be applied in an amount that connects or "crosslinks" adjacent or nearby particles in the powder feed material layer, fixing the position of the particles relative to other adsorbent particles, without necessarily filling the void spaces in the feed material layer. The "solidified" feed material is "solid" in the sense that it is rigid or solidified, sufficiently reinforced to act as a structure that supports and maintains the position of the adsorbent particles, but may contain openings, void spaces, or pores between the connected particles. The solidified feed material may, for example, contain adsorbent particles connected by a dried, cured, or otherwise continuous (not necessarily solid, but meaning without pores or interparticle spaces) polymer material that connects and maintains the position of the adsorbent particles within the solidified feed material structure.

[0118] The portion of the applied feed material layer that has not formed into solidified feed material remains as the original powder feed material.

[0119] The build plate is moved downward (114), and a second layer of feed material is formed as a second uniform feed material layer on top of the first feed material layer, which contains a portion of the solidified feed material (116). The printhead then selectively deposits a second amount of liquid polymer binder or binder component (104) onto a portion of the second feed material layer (118), and the second amount of liquid binder or binder component (104) and binder form solidified feed material from the second layer, for example by using heat to remove the solvent and form a dry (solidified) polymer binder, or by another relevant mechanism depending on the type of binder composition.

[0120] The portion of the second layer that has not formed into solidified feedstock remains as the original powder feedstock.

[0121] Steps 114, 116, and 118 are repeated (120) to form a completed multilayer composite adsorbent medium (green body) surrounded by the original powder feed material (1024). The multilayer composite adsorbent medium is a multilayer body containing solidified feed material in each formed layer, and consists of adsorbent particles of the feed material dispersed in a solidified (solid) binder. If the polymer binder is thermosetting, optionally the multilayer composite adsorbent medium may be heated in the presence of the surrounding original powder feed material to crosslink and cure the liquid polymer binder (122). The original (loose) powder feed material (102 or 104) can be removed and separated from the multilayer composite (124). Alternatively, if the binder contains water, optionally the green body multilayer composite adsorbent medium may be frozen in the presence of the surrounding original powder feed material to strengthen the green body.

[0122] The multilayer composite material can be moved to a location for any subsequent type of processing that may be useful or desired for converting the green body form of the finished, fully processed composite adsorbent medium.

[0123] Figure 4B schematically shows the steps of Technology 100 having the relevant process equipment and feedstock. Referring to Figure 4B, the exemplary process can be carried out using a commercially available binder jet printing apparatus (130), the feedstock (132) described herein containing at least two different types of adsorbent particles, and a liquid (133) dispensed from the printhead (136) of the apparatus (130). According to the exemplary steps of the Method, the feedstock (132) is formed as a feedstock layer (134) of uniform thickness and height on the build plate (138) of the apparatus (130). The feedstock layer (134) can be formed using one or more passes to uniformly form and distribute the feedstock (132) to the desired depth using rollers or other leveling devices. The printhead (136) selectively deposits the liquid (133) onto a portion of the first layer (134).

[0124] Liquid 133 may be, for example, a liquid binder composition (as described with respect to Figure 4A), or another liquid as described herein, such as water. The liquid (133) in the form of a liquid binder composition can be solidified, for example, by drying with heat to evaporate the solvent of the binder and form a first solidified feed material (140) containing a solid polymer in part. Alternatively, liquid 133 may be a binder component (104) such as water that can be applied to a feed material layer and contains a second binder component such as inorganic particles, the liquid and inorganic particles solidify to form a solidified feed material.

[0125] The portion of the feed material layer 134 that has not formed into solidified feed material (140) remains as the original powder feed material (132). The build plate (136) is moved downward (114), and a second or subsequent feed material layer (142) is formed on top of the first layer (134) and the first solidified feed material (140). The print head (136) then selectively deposits a second amount of liquid (133) onto the portion of the second layer (142), and the second amount of liquid polymer binder (133) forms solidified feed material from the second layer. The portion of the second layer that has not formed into solidified feed material remains as the original powder feed material.

[0126] The process of applying a feed material layer on top of a previous layer and applying liquid 133 to the new feed material layer to produce solidified feed material for the new feed material layer is repeated (150) to form a completed multilayer composite adsorbent medium (e.g., as a green body) (152) surrounded by the original powder feed material (132). The multilayer composite adsorbent medium (152) is a body containing solidified feed material from each formed layer and consists of at least two different types of adsorbent particles from the feed material dispersed in a solidified (solid) polymer binder. If necessary, the multilayer composite adsorbent medium can be further processed to convert the green body form of the composite adsorbent medium into a useful adsorbent material that functions as a composite adsorbent medium in the method described herein.

[0127] In an exemplary subsequent processing step, as shown in the figure, the multilayer composite adsorbent medium (152) may optionally be heated in the presence of the surrounding original powder feed material (132) to cure the liquid polymer binder (122). Alternatively, in the case of a water-containing liquid (133), the green multilayer composite adsorbent medium may optionally be frozen in the presence of the surrounding original powder feed material to strengthen the green.

[0128] The original (loose) powder feed material (132) can be removed and separated from the multilayer composite adsorbent medium (152). The multilayer composite (152) can be moved to an oven to heat to a temperature effective for removing the solidified binder from the multilayer composite (152) ("de-bindering" or "de-binding" process).

[0129] Additive manufacturing techniques known as stereolithography (SLA), as understood herein and described herein, are a version of additive manufacturing techniques that can be used to form multilayer composite adsorbent media layer by layer using a photochemical process that uses light (electromagnetic radiation) to selectively polymerize, crosslink, or otherwise chemically react chemical monomers and oligomers (collectively referred to as "polymers" or "liquid polymer binders") in a liquid feedstock layer to form a solidified feedstock cured polymer reaction product ("solidified polymer") in the feedstock layer. The liquid polymer binder is selectively curable by exposure to electromagnetic radiation such as ultraviolet (UV) light. The feedstock is in liquid form and contains a curable liquid polymer ("liquid polymer binder") in combination with at least two different types of adsorbent particles.

[0130] A multilayer composite adsorption medium is constructed by a series of steps that generate many thin cross-sections ("solidified feedstock" of the "layers" as herein) that together form a larger three-dimensional structure (composite adsorption medium). An electromagnetic radiation source (e.g., a laser) selectively applies electromagnetic radiation over a portion of the layer of the liquid feedstock, which, according to the present invention, contains at least two different types of adsorbent particles together with a liquid polymer binder that can be solidified by chemical curing upon exposure to electromagnetic radiation. The laser selectively irradiates a portion of the layer of the liquid feedstock on the surface of the layer. The electromagnetic radiation solidifies the liquid polymer binder by a chemical reaction (i.e., for curing) to form a solidified feedstock containing two or more different types of adsorbent particles and a solidified (cured) polymer.

[0131] After the initial layer of solidified feed material is formed, an additional thin layer of liquid feed material is deposited on top of the finished layer containing the solidified feed material, and the process is repeated with multiple layers formed and adhering to the top of the previous layer. Multiple layers are deposited one by one consecutively on top of each finished layer to form a multilayer composite adsorbent medium, which is an aggregate assembly of each of the individually formed layers of solidified feed material. After all the layers of the multilayer composite adsorbent medium have been formed, the portion of the layer containing the original liquid feed material that was not used to prepare the solidified feed material is separated from the multilayer composite adsorbent medium. The multilayer composite adsorbent medium can then be processed as desired to form derivative structures such as the final composite adsorbent medium useful in the method described herein, and to separate the gases of the gas mixture. Subsequent processing may include, for example, a step of removing the solidified (cured) polymer from the MOF particles (i.e., "debinding").

[0132] Figure 5A shows an example of a stereolithography additive manufacturing technique (200) useful for preparing the multilayer composite adsorption media described herein. The supply material 202 is a liquid containing at least two different types of adsorbent particles in combination with a liquid curable polymer binder.

[0133] This process can be carried out using commercially available stereolithography additive manufacturing equipment and a feed material containing a liquid polymer binder combined with two or more different types of adsorbent particles. According to exemplary steps of the exemplary method (steps numbered in parentheses as shown in Figure 5A), the liquid feed material (202) contained in the SLA additive manufacturing equipment is formed as a uniform layer (204, 206) on the build plate of the equipment. In a subsequent step (208), an electromagnetic radiation source (e.g., a UV (ultraviolet) laser) selectively irradiates a portion of this first layer with radiation of a wavelength that chemically cures and solidifies the liquid polymer binder of the feed material. The solidified liquid polymer binder forms a solidified feed material in the irradiated area.

[0134] The portion of the layer that has not formed from the solidified feedstock remains as the original liquid feedstock.

[0135] The build plate is moved downward (210), and a second layer of liquid feed material is formed as a second uniform layer on top of the first feed material layer and on top of the solidified feed material of the first feed material layer (212). The electromagnetic radiation source is then selectively irradiated to a portion of the second layer (214) to solidify (harden) a portion of the second layer of liquid feed material, forming solidified feed material in a portion of the second layer. The portion of the second layer that has not been formed into solidified feed material remains as the original liquid feed material. Steps 212, 214, and 216 are repeated (218) to form a completed multilayer solidified feed material composite ("final component") surrounded by the original liquid feed material (202).

[0136] The multilayer solidified feed material composite is a body containing solidified feed materials in each formed layer, and is composed of two or more different types of adsorbent particles dispersed in a solidified (solid) polymer binder of liquid feed materials. The original liquid feed material (202) can be removed and separated from the multilayer composite (218). The multilayer composite adsorbent medium can then be further processed to form derivative structures such as MOF-type adsorbent materials.

[0137] Referring to Figure 5B, the exemplary process can be carried out using a commercially available SLA apparatus (230) and the liquid feed material (232) as specified herein. According to the exemplary process, the liquid feed material (232) is formed as an even feed material layer (234) on the build plate (238) of the apparatus (230). A laser (236) applies electromagnetic radiation (233) to a portion of the first layer (234) to form a first solidified feed material (240) in that portion. The portion of the feed material layer (234) that has not been formed into solidified feed material (240) remains as the original liquid feed material (232). The build plate (238) is moved downward (214) and a second or subsequent liquid feed material layer (242) is formed on top of the first layer (234) and the first solidified feed material (240). Next, the laser (236) selectively applies electromagnetic radiation (233) to a portion of the second layer (242) to form solidified feed material from the second layer. The portion of the second layer that has not been formed into solidified feed material remains as the original liquid feed material. This sequence is repeated (250) to form a completed multilayer solidified feed material composite (252) surrounded by the original liquid feed material (232). The multilayer solidified feed material composite (252) is a body containing solidified feed material from each formed layer and consists of two different types of adsorbent particles from the feed material dispersed in the solidified (solid) cured polymer of the feed material.

[0138] The original liquid feed material (232) can be removed and separated from the multilayer composite material (252). The multilayer composite material (252) can then be further processed to form derivative structures such as composite adsorbents useful in the process described herein for separating gases from a gas mixture.

[0139] As an example of an additive manufacturing method that also uses a powder bed and equivalent processes, a multilayer composite adsorption medium can be formed layer by layer using a technique referred to herein as selective laser irradiation (SLI). Selective laser irradiation uses laser energy to selectively solidify a portion of the feed material layer.

[0140] More specifically, multilayer composites can be constructed by a series of steps that produce many thin cross-sections ("solidified feedstock" of the "layers" herein) of a larger three-dimensional structure (composite). The layers of solid (e.g., powder) feedstock are formed to contain a polymer binder and, in combination with these components, for example, at least two different types of adsorbent particles, as described. Laser energy is selectively applied to the feedstock layer over a portion of the layer. The laser energy solidifies the polymer binder in the portion of the feedstock exposed to the laser energy. The particles can be solidified by heating and melting by the laser energy and then resolidifying, or by a chemical reaction initiated by the laser energy.

[0141] After the initial layer of solidified feed material is formed in this manner, an additional thin layer of feed material is deposited on top of the finished layer containing the solidified feed material. The process is repeated to form multiple layers of solidified feed material, with each layer formed on top of the previous layer and adhering to its surface. Multiple layers are deposited one by one consecutively on top of each finished layer to form a multilayer composite, which is a composite of each layer of solidified feed material. The multiple layers may have the same composition and thickness, or they may have different compositions and different thicknesses.

[0142] An example of a selective laser irradiation additive manufacturing technique (300) useful for preparing multilayer composites as described is shown in Figure 6A. This process can be carried out using commercially available additive manufacturing equipment, as well as binders and particles for forming the feedstock. The feedstock 302 contains an aggregate of adsorbent particles containing at least two different types of adsorbents, and a binder containing a radiation-curable binder. According to the exemplary process shown in Figure 5A, the feedstock (302) contained in the additive manufacturing apparatus is formed as an even layer on the build plate of the apparatus (304, 306). In a subsequent step (308), an electromagnetic radiation source (e.g., a laser) selectively irradiates a portion of this first layer of the feedstock with radiation of a wavelength and energy that reacts and solidifies ("solidifies") the binder of the feedstock. The solidified binder and MOF particles form a solidified feedstock in the irradiated portion. The portion of the feedstock layer that has not formed into a solidified feedstock remains as the original liquid feedstock.

[0143] The build plate is moved downward (310), and a second layer of feed material is formed as a second uniform layer on top of the first feed material layer and on top of the solidified feed material of the first feed material layer (312). The electromagnetic radiation source is then selectively irradiated with a portion of the second layer (314), thereby solidifying the polymer of the feed material in that portion to form solidified feed material in that portion of the second layer. The portion of the second layer that has not been formed into solidified feed material remains as the original powder feed material. Steps 312, 314, and 316 are repeated (318) to form a completed multilayer solidified feed material composite surrounded by the original feed material (302).

[0144] The multilayer solidified feed material composite is a body containing solidified feed materials in each formed layer, and consists of multiple continuous layers made from the reacted polymer binder material and MOF particles of the feed materials. The original feed material (302) can be removed and separated from the multilayer composite (318).

[0145] Referring to Figure 3B, the exemplary process can be carried out using a commercially available additive manufacturing apparatus (330) and a feed material (332) in the form of a powder containing the curable polymer binder and two or more different types of adsorbent particles according to this specification. According to the exemplary steps of this method, the feed material (332) is formed as an even feed material layer (334) on a build plate (338) of the apparatus (330). A laser (336) applies electromagnetic radiation (333) to a portion of the first layer (334), thereby causing the radiation-curable polymer in the feed material to react and form a solidified feed material (340) in that portion. The portion of the feed material layer (334) that has not formed into a solidified feed material (340) remains as the original feed material (332). The build plate (338) is moved downward (314), and a second or subsequent feed material layer (342) is formed on the first layer (334) and the first solidified feed material (340). A laser (336) is then used to selectively apply electromagnetic radiation (333) to a portion of the second layer (342) to cause the radiation-curable polymer of the feed material to form solidified feed material from the second layer. The portion of the second layer that has not formed solidified feed material remains as the original powder feed material. This sequence is repeated (350) to form a completed multilayer solidified feed material composite (352) surrounded by the original feed material (332). The multilayer solidified feed material composite (352) is a body containing solidified feed material from each formed layer, and consists of solidified polymer material and adsorbent particles of feed material. The original feed material (332) can be removed and separated from the multilayer composite (352).

[0146] An example of a “supply material dispensing” additive manufacturing technique (400) useful for preparing the multilayer composite adsorption media described herein is shown in Figures 7A, 7B, and 7C. The supply material 402 is a fluid (e.g., liquid, high-viscosity liquid, or “semi-solid” fluid material) containing MOF particles in combination with a liquid-curable polymer binder.

[0147] This process can be carried out using commercially available additive manufacturing equipment and a liquid polymer binder that, in combination with MOF particles, forms a semi-solid feed material. According to an exemplary step of the exemplary method, the semi-solid feed material (402) is applied as a first feed material layer by a print head (or other useful device) (404) and solidified to form a first solidified feed material layer (410). The semi-solid feed material may be in the form of a “slurry” or “paste” containing a combination of two different types of adsorbent particles and a binder composition. The feed material in slurry or paste form is prepared by mixing fine particles or powder of adsorbent particles with a solvent to make it semi-liquid and increasing the fluidity of the fine solid adsorbent particles in powder form.

[0148] In an exemplary feedstock material useful for this type of method, the feedstock contains two different types of adsorbent particles in combination with a polymer. The exemplary polymer may be a thermopolymer or a radiation-curable polymer.

[0149] The supply material may contain useful amounts of adsorbent particles and polymers, such as a metal-organic structure adsorbent in an amount ranging from 40 to 90% by weight; a non-metal-organic structure adsorbent in an amount ranging from 0 to 30% by weight; and a polymer binder in an amount ranging from 10 to 30% by weight, based on the total weight of the supply material.

[0150] The feedstock can be solidified by any useful mechanism, depending on the type of liquid in the feedstock material. If the liquid contains a chemically curable polymer, the feedstock layer can be solidified by exposing the polymer to irradiation or heat that cures the curable polymer. If the liquid contains a thermopolymer that solidifies upon exposure to low temperatures, the liquid can be solidified by exposure to low temperatures.

[0151] In the second step, as shown in Figure 7B, a second solidification feed material layer (412) is formed on the first solidification feed material layer (410). Subsequent steps are used to form a desired number of additional layers, including a final solidification feed material layer (450), to form a multilayer composite adsorption medium 460 (see Figure 7C).

[0152] The multilayer composite material (452) can be further processed as desired to form derivative structures such as MOF-type adsorbent materials.

Claims

1. First adsorbent particles, The second adsorbent particle, A binder that holds the first adsorbent particles and the second adsorbent particles together as a composite adsorption medium. A composite adsorption medium including [this].

2. A composite adsorption medium according to claim 1, comprising a plurality of layers of a composite material formed by an additive manufacturing method.

3. The first adsorbent particle comprises a metal-organic structure adsorbent, an activated carbon adsorbent, a porous organic polymer adsorbent, or a zeolite adsorbent. The second adsorbent particle includes a metal-organic structure adsorbent, an activated carbon adsorbent, a porous organic polymer adsorbent, or a zeolite adsorbent, which is different from the first adsorbent particle. The composite adsorption medium according to claim 1 or 2.

4. A composite adsorption medium according to any one of claims 1 to 3, wherein the binder comprises a polymer binder.

5. A composite adsorption medium according to any one of claims 1 to 3, wherein the binder contains inorganic particles.

6. The first adsorbent particles are capable of adsorbing the first gas contained in a gas mixture comprising the first gas and the second gas. The second adsorbent particles are capable of adsorbing the second gas contained in the gas mixture. A composite adsorption medium according to any one of claims 1 to 5.

7. The composite adsorption medium according to any one of claims 1 to 6, wherein the first gas can be adsorbed onto the first adsorbent and selectively desorbed from the first adsorbent under selective desorption conditions that cause selective desorption of the first gas from the first adsorbent without substantial desorption of the second gas from the second adsorbent.

8. The first adsorbent particle is GeF ４ It is possible to adsorb, The second adsorbent particle is HF, PF ３ It is possible to adsorb either one or both. GeF ４ The gas is GeF from the first adsorbent particles. ４ Desorption and removal of HF and PF from the second adsorbent particles ３ It is possible to adsorb the material onto the first adsorbent particles and selectively desorb it from the first adsorbent particles under selective desorption conditions that result in a reduced amount of desorption of either or both. A composite adsorption medium according to any one of claims 1 to 7.

9. The composite adsorption medium according to any one of claims 1 to 8, wherein the form of the composite adsorption medium body is selected from geometrically shaped particles, repeating lattice structures, matrices, honeycombs, and monoliths.

10. The internal composite adsorption medium according to claim 1, A valve for controlling the flow of gas to and from the inside and outside of the storage container. A storage container equipped with [a specific feature / feature].

11. GeF adsorbed onto the first adsorbent particle ４ and, HF and PF adsorbed onto the second adsorbent particle ３ or both It further includes, GeF ４ can be selectively desorbed from the first adsorbent particles under selective desorption conditions that cause desorption of GeF ４ from the first adsorbent particles and reduced desorption amounts of HF, PF ３ or both from the second adsorbent particles The storage container according to claim 10.

12. Hydride (e.g., SiH) adsorbed onto the first adsorbent particles ４ GeH ４ Ash ３ ) or with a halide, H adsorbed onto the second adsorbent particle ２ O and It further includes, The hydride or halide is desorbed from the first adsorbent particle and H from the second adsorbent particle. ２ Under selective desorption conditions that result in a reduced amount of O desorption, it is possible to selectively desorb O from the first adsorbent particles. The storage container according to claim 10.

13. Hydride (e.g., SiH) adsorbed onto the first adsorbent particles ４ GeH ４ Ash ３ ) or with a halide, Hydrogen adsorbed onto the second adsorbent particle and It further includes, The hydride can be selectively desorbed from the first adsorbent particle under selective desorption conditions that result in the desorption of the hydride from the first adsorbent particle and a reduced amount of hydrogen from the second adsorbent particle. The storage container according to claim 10.

14. The phosphine adsorbed onto the first adsorbent particle, Diphosphen adsorbed onto the second adsorbent particle and It further includes, The phosphine can be selectively desorbed from the first adsorbent particle under selective desorption conditions that result in a reduced amount of phosphine desorbed from the first adsorbent particle and diphosphene desorbed from the second adsorbent particle. The storage container according to claim 10.

15. Germanic acid adsorbed onto the first adsorbent particle, Digermann and It further includes, Germann can be selectively desorbed from the first adsorbent particle under selective desorption conditions that result in reduced desorption of Germann from the first adsorbent particle and reduced desorption of Digermann from the second adsorbent particle. The storage container according to claim 10.

16. Fluoride (e.g., BF) adsorbed onto the first adsorbent particles ３ GeF ４ , SiF ４ , PF ３ )and, Hydrogen fluoride (HF) adsorbed onto the second adsorbent particle and It further includes, The fluoride can be selectively desorbed from the first adsorbent particle under selective desorption conditions that result in a reduced amount of fluoride desorbed from the first adsorbent particle and a reduced amount of hydrogen fluoride desorbed from the second adsorbent particle. The storage container according to claim 10.

17. A method for adsorbing multiple different gases contained in a gas mixture onto a composite adsorption medium, The gas mixture is brought into contact with a composite adsorption medium, wherein the composite adsorption medium is First adsorbent particles, The second adsorbent particle, A binder that holds the first adsorbent particles and the second adsorbent particles together as a composite adsorption medium. The process involves bringing a gas mixture containing the above into contact with a composite adsorption medium, The first gas contained in the gas mixture is adsorbed onto the first adsorbent particles, The second gas contained in the gas mixture is adsorbed onto the second adsorbent particles. Methods that include...

18. The gas mixture contains a reagent gas and two or more impurities. The first impurity is adsorbed onto the first adsorbent particle. The second impurity is adsorbed onto the second adsorbent particle. The method according to claim 17.

19. The reagent gas comes into contact with the composite adsorption medium but is not adsorbed. The reagent gas is delivered to a semiconductor manufacturing tool (e.g., an ion implantation tool or a deposition tool). The method according to claim 18.

20. The gas mixture contains reagent gas and impurities. The reagent gas is adsorbed onto the first adsorbent particle, The impurities are adsorbed onto the second adsorbent particles. The reagent gas can be selectively desorbed from the first adsorbent under selective desorption conditions that result in the desorption of the reagent gas from the first adsorbent and a reduced amount of impurities from the second adsorbent. The method according to claim 17.

21. The method according to claim 20, wherein the composite adsorption medium is housed in a storage container comprising a cylinder having an interior and a valve for controlling the flow of gas to and from the storage container.

22. The method according to claim 21, further comprising desorbing a reagent gas from first adsorbent particles and dispensing the reagent gas from a storage container to a semiconductor manufacturing tool.

23. Reagent gas is GeF ４ The impurities are HF and PF. ３ The method according to claim 22, which includes both or the same.

24. The gas mixture contains a reagent gas, a stabilizing gas, and impurities. The stabilizing gas is adsorbed onto the first adsorbent particles. The impurities are adsorbed onto the second adsorbent particles. The method according to claim 17.

25. The gas mixture includes exhaust gas containing reagent gas and impurities. The reagent gas is adsorbed onto the first adsorbent particle, The impurities are adsorbed onto the second adsorbent particles. The reagent gas can be selectively desorbed from the first adsorbent particles under selective desorption conditions that result in the desorption of the reagent gas from the first adsorbent particles and a reduced amount of impurity desorption from the second adsorbent particles. The method according to claim 17.

26. The method according to claim 25, wherein the exhaust gas is from semiconductor manufacturing tools.

27. The method according to claim 25 or 26, wherein the impurity is an inert gas such as nitrogen, helium, xenon, or argon.

28. A method for producing a composite adsorption medium, The first supply material layer is formed on the surface, wherein the supply material layer contains a supply material comprising at least one of first adsorption medium particles and second adsorption medium particles. Forming solidified feed material from the first feed material layer, The method involves forming a second supply material layer on top of a first supply material layer, wherein the second supply material layer contains a supply material including adsorption medium particles. To form a second solidified supply material from a second supply material layer. Includes, A method for forming a multilayer composite material containing first adsorption medium particles and second adsorption medium particles by combining a first supply material layer and a second supply material layer.

29. The first supply material layer is formed on the surface, wherein the first supply material layer contains a supply material that includes at least one of first adsorption medium particles and second adsorption medium particles. In a portion of the first supply material layer, a liquid is selectively applied to the supply material layer in order to generate a first supply material layer in a solidified form. The method involves forming a second supply material layer on top of a layer containing solidified supply material, wherein the second layer contains supply material containing adsorption medium particles, and the second supply material layer is formed accordingly. In a portion of the second feed material layer, a liquid is selectively applied to the second feed material layer in order to form a second solidified feed material. The method according to claim 28, including the method described in claim 28.

30. The supply raw material layer contains inorganic particles as a binder component. The liquid contains distilled water, By applying the liquid to the feed material layer, solidified feed material is produced. The method according to claim 29.

31. The method according to claim 30, comprising lowering the temperatures of a first solidification feed material layer and a second feed material layer to below 0 degrees Celsius in order to freeze the liquid.

32. The first supply material layer is formed on the surface, wherein the first supply material layer contains a binder composition and a supply material comprising at least one of first adsorption medium particles and second adsorption medium particles. In a portion of the first supply material layer, radiation is selectively applied to the first supply material layer in order to generate solidified supply material including the first supply material layer. The method involves forming a second supply material layer on top of a first supply material layer containing solidified supply material, wherein the second supply material layer contains supply material containing adsorption medium particles and a binder composition. In a portion of the second supply material layer, radiation is selectively applied to the second supply material layer in order to form a second solidified supply material layer. The method according to claim 28, including the method described in claim 28.

33. To provide a supply material containing first adsorption medium particles, second adsorption medium particles, and a binder composition, In order to form a pathway for the supply material on the surface, selective application of the supply material to the surface, wherein the pathway has an upper pathway surface, and selective application of the supply material. Solidifying the raw materials supplied in the pathway, and then, In order to form a second path for the supply material on the second surface, the supply material is applied to the upper surface. The method according to claim 28, including the method described in claim 28.

34. The method according to any one of claims 28 to 33, wherein both the feed material for the first feed material layer and the feed material for the second feed material layer comprise first adsorption medium particles and second adsorption medium particles.

35. The method according to any one of claims 28 to 33, wherein the feed material for the first feed material layer comprises one of first adsorption medium particles and second adsorption medium particles, and the feed material for the second feed material layer comprises the other of first adsorption medium particles and second adsorption medium particles.

36. A method for preparing a composite adsorption medium for processing a gas mixture, Regarding a gas mixture containing a first gas and a second gas, Selecting first adsorbent particles for adsorbing the first gas, Selecting a second adsorbent particle for adsorbing the second gas, The process involves forming a composite adsorption medium, wherein the composite adsorption medium is First adsorbent particles, The second adsorbent particle, A binder that holds the first adsorbent particles and the second adsorbent particles together as a composite adsorption medium. Forming a composite adsorption medium that includes Methods that include...

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