Membranes for removing metal species from amines

Abstract

The invention relates to a film for removing metal species from amines. The present disclosure relates to the removal of metal contaminants from fluids, as well as ligand-modified filter materials for performing such methods. The filters and methods of the present disclosure are particularly effective for removing metals from liquid compositions comprising amines. Such liquid compositions with significantly reduced amounts of metal can be used in microelectronic manufacturing processes, such as liquids for removing photoresist or liquids used in etching. A ligand-modified filter, such as a ligand-modified porous membrane, may be configured for use in a microelectronic manufacturing system, which may be used in the system as a point where metal removal features are used for liquids entering the system.

Description

[0001] This application is a divisional application of an application filed on September 29, 2021, with application number 202111149755.4 and invention name “Membrane for removing metal species from amines”. Technical Field

[0002] The following disclosure relates to ligand-modified articles, such as filtration membranes, and to methods of using the articles to remove metals from liquid compositions. Background Art

[0003] Filters are used to remove unwanted substances from useful fluid streams and have become an important feature in various industrial technologies. Fluids treated to remove unwanted substances include water, liquid industrial solvents and process fluids, industrial gases used in manufacturing or processing, and liquids with medical or pharmaceutical applications. Unwanted substances removed from fluids include impurities and contaminants, such as particles, microorganisms, and dissolved chemicals. Specific examples of filter applications include their use with liquid substances in semiconductor and microelectronic device manufacturing.

[0004] Filters can remove unwanted substances in a variety of different ways, such as by size exclusion or by chemical and / or physical interactions with the substances. Some filters are defined by a structural material that provides the filter with a porous structure, and the filter is able to retain particles of a size that cannot pass through the pores. Some filters are defined by the ability of the filter's structural material, or chemicals associated with the structural material, to associate and interact with substances flowing through the filter. For example, the chemical characteristics of the filter can associate with unwanted substances from a stream flowing through the filter, such as through ionic, coordination, chelation, or hydrogen bonding interactions, thereby retaining those unwanted substances. Some filters can utilize both size exclusion and chemical interaction characteristics to remove substances from the filtered stream.

[0005] In some cases, in order to perform filtering function, the filter includes a filter membrane that is responsible for removing unwanted substances from the fluid flowing through. The filter membrane can be in the form of a flat plate as needed, and it can be wound (for example, spiral), flat, pleated or disc-shaped. Or, the filter membrane can be in the form of a hollow fiber. The filter membrane can be contained in the housing or otherwise supported so that the filtered fluid enters through the filter inlet and needs to flow through the filter membrane before passing through the filter outlet.

[0006] Removal of ionic species (e.g., dissolved anions or cations) from solutions is important in many industries, such as the microelectronics industry, where even very small concentrations of ionic contaminants and particles can adversely affect the quality and performance of microprocessors and memory devices. In particular, it is desirable to remove metal-containing species, such as metal ions, from liquid compositions used in device manufacturing. Metal-containing species can be found in various types of liquids used in microelectronics manufacturing.

[0007] There are still various unresolved technical challenges in removing metal-containing species from fluids. In particular, there is a need for methods for removing metal ions such as Fe from fluids containing amines and amino alcohols. 2+ and Fe 3+ Aqueous amine solutions are used in the manufacture of semiconductors. For example, hydroxylamine is often a component in photoresist strippers, which remove the photoresist after photolithography. Reducing metal ion contaminants throughout the semiconductor supply chain is increasingly important in efforts to reduce defects and improve yields. Metal ion reduction is critical for substances that come into direct contact with the wafer surface, such as hydroxylamine and ammonium hydroxide. Conventional metal ion reduction methods, such as ion exchange filtration, are unable to adequately reduce metal ions from aqueous amine solutions. Hydroxylamine is particularly problematic because it forms complex structures with metals, such as transition metals, such as iron. Summary of the Invention

[0008] The present disclosure provides various inventive embodiments related to removing metal contaminants from fluids, and ligand-modified filter materials for implementing such methods. The filters and methods of the present disclosure are particularly effective for removing metals from liquid compositions. The filtered liquid compositions having a significantly reduced metal content can be used in microelectronics manufacturing processes, such as liquids for removing photoresists or liquids used in etching. Ligand-modified filters (e.g., ligand-modified porous membranes) can be configured for use in microelectronics manufacturing systems, where they are used as a point of application for metal removal features on liquids entering the system.

[0009] Thus, one aspect of the present disclosure is a film comprising:

[0010] polymers, to which ligands are attached,

[0011] The ligand comprises at least one moiety represented by the following structure:

[0012]

[0013] wherein Q is selected from -CH2-, -N(R)- or CH(N)-, and wherein R is C1-C 20 Hydrocarbyl group.

[0014] Another aspect of the present disclosure is a method for removing one or more metals or metal ions from a liquid composition. In certain embodiments, the liquid composition comprises an amine. As used herein, the term "amine" is not limited and includes, for example, primary amines, secondary amines, and tertiary amines, such amines substituted with one or more alkyl groups, hydroxyl groups, or other functional groups, and such amines in combination with water, i.e., aqueous amine solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present disclosure may be more fully understood from the following description of various illustrative embodiments considered in conjunction with the accompanying drawings.

[0016] Figure 1 is a schematic diagram of an exemplary cross-section of a filter having a single porous membrane to which a ligand of the present disclosure has been attached.

[0017] While the present disclosure is susceptible to various modifications and alternative forms, details thereof have been shown by way of example in the drawings and will be described in detail. However, it should be understood that the intention is not to limit the aspects of the present disclosure to the specific illustrative embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure. DETAILED DESCRIPTION

[0018] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and / or" unless the content clearly dictates otherwise.

[0019] The term "about" generally refers to a range of numbers that are considered equivalent to the stated value (e.g., having the same function or result). In many cases, the term "about" may include numbers that are rounded to the nearest significant figure.

[0020] The recitation of numerical ranges using endpoints includes all numbers subsumed within that range (eg, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0021] The following detailed description should be read with reference to the accompanying drawings, in which similar elements in different figures are numbered the same. The detailed description and the drawings, which are not necessarily drawn to scale, depict illustrative embodiments and are not intended to limit the scope of the invention. The illustrative embodiments depicted are intended to be examples only. Selected features of any illustrative embodiment may be incorporated into additional embodiments unless expressly stated to the contrary.

[0022] A first aspect of the present disclosure is a membrane comprising:

[0023] polymers, to which ligands are attached,

[0024] The ligand comprises at least one moiety represented by the following structure:

[0025]

[0026] wherein Q is selected from -CH2-, -N(R)- or CH(N)-, and wherein R is C1-C 20 Hydrocarbyl group.

[0027] In one embodiment, the term "C1-C 20 "Hydrocarbyl" refers to a saturated or unsaturated, straight chain, branched or cyclic hydrocarbon having 1 to 20 carbon atoms and optionally substituted with one or more heteroatoms and functional groups. Exemplary functional groups include halogen, nitro, cyano, amino, alkoxy or alkanoyloxy. The wavy line above (i.e. ) represents the point of attachment of the moiety to the membrane or to another atomic group forming the remainder of the ligand.

[0028] In certain embodiments, the ligand comprises at least one guanidine moiety. In other embodiments, the ligand comprises at least one amidine moiety. In other embodiments, the ligand comprises at least one moiety having the structure:

[0029]

[0030] In certain embodiments, the ligand comprises a guanidine moiety linked through a benzyl group having the structure:

[0031]

[0032] wherein each R is independently selected from hydrogen, C1-C4 alkyl, cyclohexyl and phenyl.

[0033] In certain embodiments, the ligand comprises a compound having the structure:

[0034]

[0035] In other embodiments, the ligand comprises a guanidine moiety having structure (IV):

[0036] In another embodiment, the ligand comprises an amidine moiety:

[0037]

[0038] In one embodiment, the ligand comprises a portion of a compound selected from the following structures:

[0039]

[0040]

[0041] In this example, it will be appreciated that in certain of the above structures, the point of attachment is a quaternary nitrogen atom. Counterions (not shown) are generated from the starting materials that react with the ring system and are selected from halogens.

[0042] In another embodiment, the ligand is selected from the following structures:

[0043]

[0044]

[0045] In one embodiment, the ligand is selected from polyguanidine. Examples of polyguanidine include the following:

[0046]

[0047]

[0048] In this embodiment, the ligand can be linked or attached to the polymer membrane via one of the free amine groups that reacts with a group on the polymer surface or with another species present on the polymer surface, thereby forming a coating comprising the ligand.

[0049] In one embodiment, the ligand comprises the structure:

[0050]

[0051] In one embodiment, the filter membrane is in the form of a porous membrane.

[0052] The filter material to which the ligand is attached can be made of any suitable substance or combination of substances. Exemplary filter materials may include one or more of polymers, metals, ceramics, or natural substances. In addition, in some aspects, the material of the filter may have a chemical structure suitable for attachment to the ligand. Alternatively, the surface of the filter material may be modified so that it reacts chemically with the ligand or its derivatives. The ligand as described above may be fixed or attached to the porous polymer membrane below.

[0053] "Filter" refers to an object having a structure including a filtration membrane. For example, the filter can be in any form useful for filtration processes, such as a porous membrane, and the filter can be made of one or more filtration materials (e.g., polymers, including synthetic and natural polymers, metal-containing substances, such as alloys, natural substances, ceramics, carbon fibers, etc.). In some embodiments, the ligand can be covalently bound to the filtration membrane.

[0054] The filter can be in any desired form suitable for filtering applications. The material forming the filter can be a structural component of the filter itself and provide the required structure for the filter. The filter can be porous or non-porous and can be any desired shape or configuration. The filter itself can be a single object, such as a nonwoven porous filter membrane.

[0055] In some embodiments, the filter material is formed from a polymeric material, a mixture of different polymeric materials, or a polymeric material and a non-polymeric material. The polymeric materials forming the filter can be cross-linked together to provide a filter structure having a desired degree of integrity.

[0056] Polymer materials that can be used to form the membranes (i.e., filter membranes) of the present disclosure include hydrophobic polymers. In some embodiments, the membranes include polyolefins or halogenated polymers. Exemplary polyolefins include polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polybutylene (PB), polyisobutylene (PIB), and copolymers of two or more of ethylene, propylene, and butylene. In another specific embodiment, the membrane includes ultra-high molecular weight polyethylene (UPE). UPE filter materials (e.g., UPE membranes) are typically composed of polymers with a molecular weight (weight average molecular weight) greater than about 1x10 6 Dalton (Da), for example, at about 1x10 6 –9x10 6 Da or 1.5x 10 6 –9x10 6 Resin formation in the Da range. Crosslinking between polyolefin polymers (e.g., polyethylene) can be promoted by the use of heat or crosslinking chemicals, such as peroxides (e.g., dicumyl peroxide or di-tert-butyl peroxide), silanes (e.g., trimethoxyvinylsilane), or azo ester compounds (e.g., 2,2'-azo-bis(2-acetoxy-propane). Exemplary halogenated polymers include polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), fluorinated polyethylene (FEP), polyhexafluoropropylene, and polyvinylidene fluoride (PVDF).

[0057] In other embodiments, the membrane comprises a polymer selected from polyamide, polyimide, polysulfone, polyethersulfone, polyarylsulfone polyamide, polyacrylate, polyester, nylon, cellulose, cellulose ester, polycarbonate, or combinations thereof.

[0058] The ligand of the above structure (II) can be synthesized by the method described in U.S. Patent No. 5,767,229, which is incorporated herein by reference. The ligand of the above structure (III) can be synthesized as shown in Example 7 below. The ligand of the above structure (V, VI, VII) can be synthesized by reacting the corresponding cyclic amidine (tricyclic 2,4-diaminovinamidine and pentacyclic amidine, German Journal of Applied Chemistry - International Edition (Angewandte Chemie - International Edition), 26, 1164-1165. German Journal of Applied Chemistry - International Edition, 26, 1165-1167. Australian Chemical Technology and Laboratory News (Nachrichtenaus Chemie Technikund Laboratorium), 38, 1214-1226) with glycidyl vinyl ether or 4-chloromethylstyrene.

[0059] The ligands of the present disclosure can be bound or attached to the underlying porous membrane by a variety of methods. See, for example, the methods described in U.S. Patent Publication No. 2020-0254398, which is incorporated herein by reference.

[0060] In general, the ligands of the present disclosure can be connected to the polymer membrane by connecting to a reactive cross-linking coating. For example, the filter material can be coated with a solution of an amine-reactive polymer such as poly(vinylbenzyl chloride), poly(epichlorohydrin) or an epoxy resin. The coated and dried membrane can then be cross-linked by reacting with a diamine, polyamine or any other multifunctional reactive cross-linking agent and the remaining reactive sites for connecting the desired ligand. Using a similar approach, cross-linking and ligand attachment can occur simultaneously, wherein the ligand itself acts as a cross-linking agent. In one practical mode, the desired ligand is first reacted with a halogenated compound having ethylenic unsaturation, such as 4-(chloromethyl)styrene. The ligand thus having a vinylbenzyl group can then be applied to the porous membrane as a solution together with another reactive compound used as a cross-linking agent (e.g., N,N'-methylenebis(acrylamide)) and then in the presence of a suitable photoinitiator (e.g., 2959) is subjected to UV radiation to provide a cross-linked coating on the porous membrane, the coating having the desired ligand covalently bound therein. Other examples of cross-linking agents include triethylene glycol dimethacrylate, triethylene glycol diacrylate and ethylene glycol divinyl ether, etc. In another practical mode, the ligand of the present disclosure can be grafted onto the membrane using the method taught in U.S. Patent Publication 2020-0254398 (incorporated herein by reference) and WO2017 / 205722. This grafting can be achieved by ultraviolet irradiation of the polymer film in the presence of a photoinitiator and an unsaturated monomer comprising the ligand of the present disclosure. In another practical mode, grafting can utilize electron beam or gamma radiation.

[0061] The concentration of the ligand can be sufficient to immobilize the ligand on the surface of the filter material at a desired density. The ligand solution can be applied to the surface of the filter material by any suitable technique, such as spraying, immersing, soaking the filter material in the solution, etc. Ideally, the entire surface of the filter can be in contact with the solution, such as the entire inner surface of a porous filter membrane. If desired, the application step can include manipulation of the filter material, such as by rolling or squeezing the porous filter medium to cause wetting of all surfaces of the porous filter.

[0062] In various examples of the methods and devices of the present specification, the filter comprises a porous filter membrane in which a ligand is attached to a polymeric material forming the membrane. As used herein, a "porous filter membrane" is a porous solid comprising porous (e.g., microporous) interconnected channels extending from one surface of the membrane to the opposite surface of the membrane. The channels typically provide tortuous tunnels or paths through which the liquid to be filtered must pass. Metal species that are small enough to pass through the membrane pores can be retained on the membrane by interaction with the ligand (e.g., by chelating interactions between the ligand and the metal). This is referred to as a "non-sieving filtration mechanism."

[0063] The filter can also function to prevent any particles present in the liquid that are larger than the pores (e.g., metal-containing particles) from entering the microporous membrane, or can function to trap the particles within the pores of the microporous membrane (i.e., where the particles are removed by a sieving-type filtration mechanism). The liquid to be treated can pass through the membrane, resulting in a flow through having a reduced amount of metals, such as a reduced amount of ionic metal species, a reduced amount of metal-containing particles, or both.

[0064] Thus, the porous polymer membrane to which the ligands are attached can remove metal and metal ion contaminants from the solution passing through the membrane, as well as any species that are too large to pass through the membrane pores.

[0065] The porous membranes of the present disclosure may be described by reference to one or more properties of the membrane. Example porous polymer filtration membranes, such as those described herein, can be characterized by physical characteristics including pore size, bubble point, and porosity. For example, a membrane can be described by its bubble point, which is typically used to reflect pore size.

[0066] The bubble point method is based on the premise that for a specific fluid and pore size with constant wettability, the pressure required to force a bubble of air through the pore is inversely proportional to the size of the pore. The capillary diameter can be calculated by measuring the pressure required to force water out of the capillary. The porosity bubble point test method measures the pressure required to push air through the wet pores of a membrane. Therefore, the bubble point test is a well-known method for determining membrane pore size. To determine the bubble point of a porous material, a sample of the porous material is immersed in ethoxy-nonafluorobutane HFE 7200 (available from 3M) at a temperature of 20-25°C (e.g., 22°C) and wetted with it. Air pressure is applied to one side of the sample using compressed air and the pressure is gradually increased. The pressure difference at which the wet flow equals half the dry flow (the flow without the wetting solvent) is called the bubble point.

[0067] In certain aspects of the present disclosure, the porous polymer membrane may have a bubble point ranging from about 2 psi to about 400 psi, about 4 psi to about 200, or about 4 psi to about 160 psi when using ethoxy-nonafluorobutane (HFE-7200) as the wetting solvent and the temperature is 22°C.

[0068] Alternatively, pore size can be measured by known techniques, such as by mercury porosimetry (MP), scanning electron microscopy (SEM), liquid displacement (LLDP), or atomic force microscopy (AFM).

[0069] The porous polymer filter membrane can have any pore size that allows the filter membrane to be effectively used as a filter membrane. The pore size can be related to the bubble point determination. In some embodiments, the average pore size of the porous membrane can be in the range of about 0.001 micron to about 5 or 10 microns, for example, 0.01 to 0.8 microns. The average pore size can be selected based on one or more factors, including: fluid flow rate, pressure, pressure drop considerations, viscosity considerations, impurities in the liquid to be treated (e.g., the amount of metallic impurities) and any particle size of the impurities.

[0070] In addition, the present disclosure contemplates the use of polymer membranes having generally uniform pore size due to a higher degree of pore symmetry, as well as membranes having non-uniform pore size (variable pore diameter) due to pore asymmetry. The pores can be isotropic or anisotropic, skinned or non-skinned, symmetric or asymmetric, and any combination of these.

[0071] The porous polymer filter layer as described can have any porosity that allows the porous polymer filter layer to be effective as described herein. Example porous polymer filter layers can have a relatively high porosity, such as at least 60%, 70%, or 80% porosity. As used herein and in the field of porous bodies, the "porosity" (sometimes also referred to as void fraction) of a porous body is a measure of the void (i.e., "empty") space in the body, expressed as a percentage of the total volume of the body and calculated as the fraction of the void volume of the body to the total volume of the body. A body with a porosity of zero is completely solid.

[0072] The filter membranes of the present invention can be used in any type of industrial process that requires a liquid material containing a high-purity amine as an input. Non-limiting examples of such processes include processes for manufacturing microelectronic or semiconductor devices, with a specific example being a method for filtering liquid processing materials used in semiconductor lithography. The filters of the present disclosure can remove particles containing metal ions and metals from process liquids or solvents used in the manufacture of microelectronics or semiconductors, and can also remove other non-metallic particulate matter through the sieving action of the membrane. In particular, the filters of the present disclosure are particularly effective in removing iron ions from amine-containing liquids.

[0073] The porous membrane of the present disclosure can have any desired geometric configuration suitable for use in systems for reducing metal or metal ion contamination in fluid logistics. For example, the porous membrane described herein can have any one or more of a variety of geometric configurations or forms. For example, the porous membrane can have any one or more shapes selected from a circle, a semicircle, an ellipse, a semi-ellipse or a polygon such as a square, a rectangle, a hexagon or an octagon. The porous membrane can be particularly flat, corrugated, pleated, and hollow fibers.

[0074] The porous polymeric filtration membranes as described may be in the form of sheets or hollow fibers of any useful thickness, for example a thickness in the range of 20 to 400 microns, such as 40 or 80 to 100 or 200 microns.

[0075] The porous membranes of the present disclosure may be associated with a support structure, a housing, or both. For example, the coated porous membrane may be supported by a frame, a bracket, a clamp, a web, a mesh, a cage, or the like. In some configurations, at least a portion of the support structure may be a housing, as described herein. Alternatively, the porous membrane may be unsupported.

[0076] Porous membrane can exist as a part of the filter assembly including housing. For example, the housing is fluid-tight (except inlet and outlet ports) and can accommodate a certain volume of liquid and is configured to allow liquid to pass through the membrane. The housing can be used to form a larger filter structure, such as the filter element used in the filter assembly (single layer or multilayer) or the filtration system. The filtration system places the filter membrane in the filter housing, such as as a part of the filter assembly or as a part of the filter element, to expose the filter membrane to the flow path of the liquid chemical, to cause at least a portion of the liquid chemical to flow through the filter membrane, so that the filter membrane removes a certain amount of impurities or contaminants from the liquid chemical. The structure of the filter assembly or the filter element can include one or more various additional materials and structures, which support the composite filter membrane in the filter assembly or the filter element to cause the fluid to flow through the filter material (for example, filter membrane) from the filter inlet, and pass through the filter outlet. The filter membrane supported by the filter assembly or the filter element can be in any useful shape, such as especially pleated cylinder, cylindrical pad, one or more non-pleated (flat) cylindrical plates, pleated plates.

[0077] One embodiment of the present disclosure includes a filtration apparatus and method for removing metal contaminants from a liquid, wherein the liquid is passed through a porous polymer membrane having ligands immobilized thereon. Figure 1 As shown, the present disclosure provides a filter 100 comprising a porous polymer membrane 102. The porous polymer membrane 102 includes a ligand immobilized on the membrane surface. The filter 100 may have a housing 104 that provides structure to the filter 100 and fluidically seals the interior of the filter. The housing 104 may be of any shape and size, such as cylindrical, polygonal, etc.

[0078] The part of filter can comprise inlet port 106, to receive the fluid composition containing metal / metal ion to be filtered.Inlet port 106 can be configured to be connected to fluid supply line.Therefore, inlet port 106 can comprise valve, gasket etc. (not shown) to promote to be connected with fluid supply.The fluid composition containing metal / metal ion to be filtered can flow through inlet port 106 along the direction indicated by arrow 116, and enters the head space 114 in filter 100, and described head space is defined by the surface 124 towards input of porous polymer membrane 102, the inner surface of shell 104 and inlet port 106.In an embodiment, filter can be configured to make the volume of head space be the expectation percentage of the total internal volume of filter.

[0079] The inner portion of the filter may include a porous membrane in any suitable location or configuration. Figure 1A porous polymer membrane 102 having a disc-like structure is shown (a cross-sectional view is shown). One side 122 of the porous polymer membrane 102 (e.g., the outer circumference of the membrane) can be in contact with the inner surface of the housing 104. The porous polymer membrane 102 can also have an input-facing surface 124 (which first contacts the metal / metal ion-containing fluid) and an output-facing surface 126, from which the treated fluid with a reduced amount of metal / metal ions flows. Aspects of the filter can optionally be described in terms of a range of ratios of the surface area of ​​the input-facing surface 124 to the volume of the porous polymer membrane 102, or a range of ratios of the surface area to the thickness of the filter.

[0080] The filter 100 may also include one or more features that support the porous polymer membrane 102 within the filter. Any configuration for supporting the filter may be used and may include one or more different structural features, such as frames, brackets, brackets, clips, webs, meshes, cages, etc., or may use adhesives to support the membrane. A combination of adhesives and structural support features may be used. In one embodiment, reference Figure 1 The filter includes a frame having frame portions 110 and 112, wherein the frame portion 110 contacts the inner surface of the housing 104 and the housing 104 is attached to the portion 112. The portion 112 may be in contact with the output-facing surface 124 of the porous polymer membrane 102 and may provide support for the membrane during the filtration process. The frame portion 112 may have a lattice-like structure to freely allow the filtered liquid to enter the back space 120 of the filter while still providing structural support for the polymer porous membrane under increased fluid pressure.

[0081] In use, liquid enters the filter through the inlet port 106 in the direction indicated by arrow 116 and fills the head space 114 within the filter 100. Sufficient fluid pressure is applied to move the fluid through the porous polymer membrane at the desired flow rate.

[0082] Exemplary flow rates for porous membranes range from about 0.1 L / min to about 40 L / min, or from about 5 L / min to about 20 L / min. Alternatively, the flow rate for a porous membrane is expressed as the amount of liquid per unit area of ​​the filter per unit time (e.g., liters / m 2 / h=LMH), such as about 100 LMH / bar to about 30,000 LMH / bar, or more preferably about 5,000 LMH / bar to about 15,000 LMH / bar.

[0083] In certain embodiments, the filter of the present disclosure includes a composite membrane configuration. For example, the filter with a composite membrane can include two or more filter materials, such as two or more filter objects. For example, the filter can include a first porous polymer membrane comprising one of the ligands and a second filter material that does not include the ligand (that is, different ligands or some other ligands) present in the first porous polymer membrane, or a second filter material that is different from the first porous polymer membrane in some aspects. The second filter material can also be in the form of a porous membrane, or can be different, such as having a non-porous form. The second filter material can be made of a polymer material that is identical or different from the first membrane, and can be modified, such as modified with a ligand (such as, ligand) that is not present in the first membrane, or unmodified.

[0084] In some embodiments, the filter comprises a first porous polymer membrane comprising a ligand and a second porous polymer membrane that does not comprise a ligand or comprises a different ligand. In certain embodiments, the first porous polymer membrane and the second porous polymer membrane are composed of the same or similar polymer materials and have the same or similar pore sizes. In other embodiments, the first porous polymer membrane and the second porous polymer membrane are composed of different polymer materials and / or have different pore sizes.

[0085] The filters described in the present disclosure can be used to filter liquids to remove unwanted metal-containing substances (e.g., contaminants or impurities) from the liquid to produce a high-purity liquid that can be used as an industrial process material. In particular, porous polymer filtration membranes can be used to remove dissolved and / or suspended metal-containing contaminants from liquids flowing through the membrane using a combination of a sieving mechanism and ligand binding of metal ions. That is, larger metal-containing particles can be retained by the filter due to size restriction based on the pore size, while metal ions that would otherwise pass through the pores are retained by interacting with ligands immobilized on the membrane.

[0086] Filter materials comprising ligands can be used to remove metals and metal ions from fluids where the levels of these substances are too high for the desired process.

[0087] Exemplary metals that can be removed from fluids using the ligand-modified filter materials of the present disclosure include alkali metals, which include the following chemical elements in Group 1 of the periodic table: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs). Other exemplary metals that can be removed from fluids using the ligand-modified filter materials of the present disclosure include alkaline earth metals, which are the following chemical elements in Group 2 of the periodic table: beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). Other exemplary metals that can be removed from fluids using the ligand-modified filter materials of the present disclosure include transition metals, which are elements in the d-block of the periodic table, including Groups 3 to 12 of the periodic table, and include, but are not limited to, transition metals such as titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), yttrium (Y), zirconium (Zr), molybdenum (Mo), ruthenium (Ru), palladium (Pb), silver (Au), cadmium (Cd), tungsten (W), and mercury (Hg). Other exemplary metals that can be removed from fluids using the ligand-modified filter materials of the present disclosure include late transition metals (Groups 13-15), including aluminum (Al), gallium (Ga), indium (In), tin (Sn), thallium (Tl), lead (Pb), and bismuth (Bi). In one embodiment, the ligand-modified filters of the present disclosure preferentially remove substantially all of the iron and zinc from such solutions. In one embodiment, the ligand-modified filter materials of the present disclosure remove substantially all of the iron from such solutions, for example, down to less than about 1 ppb (parts per billion).

[0088] Metal contaminants can refer to neutral, negatively charged or positively charged metal species and combinations thereof that may exist when in equilibrium. Metals can be present in liquids in the form of dissolved ions, suspended charged particles, colloids or other aggregates, and any of these metal forms can be removed from the fluid comprising it using a ligand-modified filter material of the present disclosure. Several metal ions (such as Fe and Al) can exist in water in the form of oxides. These kinds of ions can form amphoteric colloidal particles or complexes. Under alkaline conditions, some metal ions can exist in the form of hydroxides, oxides, oxyhydroxides and other anions or any combination of these. In some fluids, metal ions can form amphoteric substances and can include one or more of these groups, and these can exist in the form of cationic or anionic complexes according to the conditions (pH, temperature, ionic strength) of the fluid.

[0089] Ion chromatography can be used to detect metal ion impurities in various fluids.The removal of metal species from fluids processed by the filters of the present disclosure can also be determined using inductively coupled plasma mass spectrometry (ICP-MS).

[0090] As mentioned above, in one embodiment, the liquid composition comprises an amine. As used herein, the term "amine" is not limiting in any way and generally refers to any compound comprising a moiety of the formula

[0091]

[0092] and may be selected, for example, from primary, secondary and tertiary amines, and such amines substituted with one or more hydroxyl, alkyl or other functional groups. Examples include:

[0093] Hydroxylamine

[0094] Ethanolamine

[0095] triethanolamine

[0096] Diethylenetriamine

[0097] Methylamine

[0098] Ethylamine

[0099] Trimethylamine

[0100] Triethylamine

[0101] 3-Diethylaminopropylamine

[0102] Pyrrole

[0103] 1,2-Diaminopropane

[0104] Pyrrolidine

[0105] Anisole

[0106] aniline

[0107] N,N-Dimethylaniline

[0108] 4-Nitroanisole

[0109] 3-Nitroanisole

[0110] 4-Trifluoromethylaniline

[0111] Dopamine

[0112] adrenaline

[0113] Norepinephrine

[0114] n-Butylamine

[0115] sec-Butylamine

[0116] tert-Butylamine

[0117] N-Methyldiethanolamine

[0118] N-tert-Butyldiethanolamine

[0119] 2-Dimethylaminoethanol

[0120] 2-(Diethylamino)ethanol

[0121] 2-(Dibutylamino)ethanol

[0122] 1-[2-(Diethylamino)ethoxy]ethanol

[0123] 6-Dimethylamino-1-hexanol

[0124] diisopropylamine

[0125] 2-(Diethylamino)-1,2-propanediol

[0126] 3-Dimethylamino-1-propanol

[0127] 3-Diethylamino-1-propanol

[0128] N-tert-Butyldiethanolamine

[0129] (2-Methylbutyl)amine

[0130] Tri(2-ethylhexyl)amine

[0131] 4-Pentyn-1-amine

[0132] 1,4-Benzodioxin-6-amine

[0133] (3-Methylphenyl)amine

[0134] Allylamine

[0135] Cyclohexylamine

[0136] (3-Butoxyphenyl)amine

[0137] 4,5,6-Trimethylpyrimidin-2-amine

[0138] 1-Benzyl-1H-pyrazol-3-amine

[0139] 1-Ethyl-1H-imidazol-3-amine

[0140] Diallylamine

[0141] 1-Isobutyl-1H-benzimidazol-2-amine

[0142] 1-propyl-1H-tetrazol-5-amine

[0143] (1-Cyclopropylpropyl)amine

[0144] (2-Cycloheptylethyl)amine

[0145] (2-Cyclooctylethyl)amine

[0146] (3-Cyclopentylpropyl)amine

[0147] 1,2-Benzisoxazol-6-amine

[0148] 1,5-naphthyridin-3-amine

[0149] 1,6-naphthyridin-2-amine

[0150] 1-Methyl-1H-benzimidazol-6-amine

[0151] 1-Methyl-1H-pyrazol-4-amine

[0152] 2,4,6-Trifluorobenzylamine

[0153] 2,4,6-Trimethylpyridin-3-amine

[0154] 2-Chlorobiphenyl-4-amine

[0155] 2-Ethylcyclopropan-1-amine

[0156] The filter membranes of the present disclosure can be used in any type of industrial process requiring a high-purity liquid substance as input. Non-limiting examples of such processes include processes for manufacturing microelectronic or semiconductor devices, processes for manufacturing pharmaceutical compositions, and diagnostic (e.g., medical diagnostic) compositions and methods. The methods and filters disclosed herein can be used in any of these areas.

[0157] A specific example is a method for filtering liquid processing materials for semiconductor lithography. Examples of contaminants present in process liquids or used to manufacture microelectronics or semiconductor devices can include metal ions dissolved in the liquid, solid particles suspended in the liquid, and gelled or coagulated materials present in the liquid (e.g., produced during lithography). In an embodiment, the method and filter of the present disclosure are used to provide a purified, low-metal content liquid composition for a front-end cleaning tool that is used to create the foundation of an integrated circuit. For example, the filter of the present disclosure can be used to purify cleaning agents and etchants to minimize product contamination and improve process efficiency (e.g., etching rate). In chemical mechanical polishing processes, water is used in addition to reagents and abrasive particles.

[0158] Examples

[0159] Example 1 - Cleaning of Porous Polymer Resins

[0160] The following example demonstrates a method for cleaning porous polymeric resins for the removal of trace metals from amines and aqueous amines.

[0161] First, 50 grams of each porous polymer resin was weighed and placed in a clean 1-liter PTFE bottle (Savillex). The resin was washed with 500 mL of IPA (isopropyl alcohol). After one hour, the resin was allowed to settle and the IPA was decanted. Next, the resin was exposed to 500 mL of 70% IPA / 10% HCl (37% hydrochloric acid). The resin was then washed and exchanged into 500 mL of 2% NH4OH (29% ammonium hydroxide) and stirred gently for 1 hour. After one hour, the resin was allowed to settle and the 70% IPA / 10% HCl was decanted. Next, the resin was washed and exchanged into deionized water (DIW) several times and the DIW was decanted. Next, the resin was exchanged into 500 mL of 2% NH4OH (29% ammonium hydroxide) and stirred gently for 1 hour. MB, KMG) and gently stirred for 1 hour. Next, the resin was washed and exchanged into DIW several times, and the DIW was decanted. Next, the resin was exposed to 500 mL of 10% HCl and gently stirred for 16 hours. After 16 hours, the resin was allowed to settle and the 10% HCl was decanted. Finally, the resin was exchanged several times with DIW, then with IPA, and placed in a convection oven at 70°C until dry. The clean and dry resin was placed in a clean PTFE jar until use.

[0162] Example 2 - Static immersion test to measure the Porous polymer resin reduces metal species in hydroxylamine by 25%

[0163] The following example demonstrates a method for measuring the ability of a porous polymeric resin containing 1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD) to reduce metal concentrations in 25% hydroxylamine under static immersion conditions. The results demonstrate that the resin with TBD effectively reduces metal species, including from solution upon contact with the resin.

[0164] A method similar to that of Example 1 was used to clean the cross-linked poly(styrene-co-divinylbenzene) resin ( PS-TBD, Biotage). A 25% hydroxylamine solution containing Fe was obtained. Next, 0.2 g of clean and dry resin was weighed out and placed in a clean 25 mL PTFE jar (Savilix). Next, 20 mL of 25% hydroxylamine solution was added to the PTFE jar containing the clean resin. The jar was capped and rotated for 16 hours. After 16 hours, the resin was allowed to settle and the liquid was decanted into a vial for analysis. The metal concentration of each liquid sample was measured by ICP-MS (inductively coupled plasma mass spectrometry). The entire experiment was run in duplicate to ensure repeatability. The experiment showed that the resin cross-linked poly (styrene-to-divinylbenzene) resin with the connected TBD was able to reduce metal species from a 25% hydroxylamine solution, including a reduction of >96% of Fe, while also effectively removing more than 50% of Na, K, Mg, Mn, Cr, Al, Ni, Zn, Ba and Pb.

[0165] Example 3 - Preparation of Reactive 1,5,7-Triazabicyclo[4,4,0]dec-5-ene Vinyl Monomer

[0166] The following example demonstrates a method of making a solution containing a reactive vinyl monomer having a 1,5,7-triazabicyclo[4,4,0]dec-5-ene moiety.

[0167] In a jar, a solution was prepared by dissolving 4.2 g of 1,5,7-triazabicyclo[4,4,0]dec-5-ene (CAS#5807-14-7, Sigma) in 17.5 g of deionized water. A separate solution was prepared by dissolving 4-(chloromethyl)styrene (CAS#1592-20-7, TCI) in 43.7 g of dimethylformamide. The 4-(chloromethyl)styrene / dimethylformamide was added to the jar containing the 1,5,7-triazabicyclo[4,4,0]dec-5-ene / deionized water. The jar containing the resulting mixture was capped tightly and the solution was rotated at 80°C for 6 hours. After 6 hours, the jar containing the resulting solution was removed from the heat source and cooled to room temperature.

[0168] Example 4 - UPE membrane with a stable surface coating containing (1,5,7-triazabicyclo[4,4,0]dec-5-ene) Preparation method

[0169] This example demonstrates the surface modification of a 50 nm pore size grade UPE membrane with a stable surface coating containing a (1,5,7-triazabicyclo[4,4,0]dec-5-ene) ligand.

[0170] The surface modification was achieved by applying a photo-initiated cross-linking coating that incorporated the vinylbenzyl-(1,5,7-triazabicyclo[4,4,0]dec-5-ene) monomer produced in Example 3. First, a monomer solution was made by adding 7 wt% vinylbenzyl-(1,5,7-triazabicyclo[4,4,0]dec-5-ene), 2% methylenebisacrylamide, 0.4% Irgacure 2959, 10% deionized water, and 80.6% isopropyl alcohol. Next, the unmodified 50nm UPE membrane was cut into 47mm diameter coupons and then immersed in the monomer solution. The coupons were then removed from the monomer solution and immediately placed between two clear polyethylene plates, and the excess liquid was wiped off using a rubber roller. The monomer-absorbing membrane coupons were then removed from the polyethylene plates and allowed to air dry for 15 minutes. After drying for 15 minutes, the dried coupons were washed with HT 135 (Solvay) was wetted and immediately placed between two polyethylene sheets and passed over a Fusion Systems broadband UV lamp at a speed of 6 feet per minute. The UV cured film specimens were removed from the polyethylene sheets, allowed to dry, washed with isopropyl alcohol, water, and twice with methanol, and then dried.

[0171] Example 5 - Static immersion test to measure the The UPE membrane reduced Fe in ammonium hydroxide by 2% and 14%

[0172] The following example demonstrates a method for measuring the ability of a 50 nm pore-size grade UPE membrane containing (1,5,7-triazabicyclo[4,4,0]dec-5-ene) to reduce Fe concentrations in 2% and 14% NH₄OH under static immersion conditions. The results demonstrate that the UPE membrane containing (1,5,7-triazabicyclo[4,4,0]dec-5-ene) effectively removes Fe from both 2% and 14% NH₄OH following contact with the membrane.

[0173] First, a 50 nm pore size grade UPE membrane containing (1,5,7-triazabicyclo[4,4,0]dec-5-ene) was prepared using a method similar to that of Example 4 and then cut into 47 mm coupons. Next, the membrane coupons were cleaned using a method similar to that of Example 1. Next, 2% and 14% NH4OH solutions were spiked with a target concentration of 2500 ppt of Fe using PlasmaCAL Single Element Calibration Standards (SCP Science, Canada). Next, the cleaned 47 mm coupons were placed in separate clean 25 mL PTFE jars (Savilix), and 2% and 14% Fe-doped NH4OH were added to each jar. The PTFE jars containing NH4OH and membrane coupons were capped and rotated for 16 hours. After 16 hours, the jars were opened and the membrane coupons were removed. The metal concentrations of the membrane-treated NH4OH were measured using inductively coupled plasma mass spectrometry (ICP-MS). The results showed that after membrane treatment, Fe was reduced by approximately 94% in 2% NH4OH and by approximately 88% in 14% NH4OH. The reduction in Fe in the membrane-treated samples demonstrates the ability of the UPE membrane, incorporating (1,5,7-triazabicyclo[4,4,0]dec-5-ene) into the surface coating, to remove Fe from 2 and 14% NH4OH solutions when exposed to the solution.

[0174] Example 6 - Static Soaking Test to Measure 25% Reduction of Hydroxyl by a Porous Polymer Resin Containing a Bis-Spiral Amine Ligand Metal species in amines

[0175] The following example demonstrates a method for measuring the ability of a porous polymer resin containing a di-helix amine to reduce metal concentrations in 25% hydroxylamine under static immersion conditions. The results indicate that the resin containing a di-helix amine can effectively reduce metal species in solution after contact with the resin.

[0176] A resin having macroporous polystyrene cross-linked with a divinylbenzene polymer backbone and connected to a dispirolamine (Puromet MTS9600, Purolite) was cleaned using a method similar to Example 1. A 25% hydroxylamine solution containing a given Fe concentration was obtained. Next, 0.2 g of clean and dry resin was weighed out and placed in a clean 25 mL PTFE jar (Savilix). Next, 20 mL of 25% hydroxylamine solution was added to the PTFE jar containing the clean resin. The jar was capped and rotated for 16 hours. After 16 hours, the resin was allowed to settle and the liquid was decanted into a vial for analysis. The metal concentration of each liquid sample was measured by ICP-MS. The entire experiment was run in duplicate to ensure repeatability. The experiment showed that the resin having macroporous polystyrene cross-linked with a divinylbenzene polymer backbone and connected to a dispirolamine was able to reduce certain metal species from 25% hydroxylamine by connecting the resin to the dispirolamine. In this case, Fe was reduced by about 77%, and Na and Mg were reduced by more than 50%.

[0177] Example 7 - Proposed Preparation of Ligand (III)

[0178] Di-tert-butyl dicarbonate is added dropwise to a solution of 2-chloroimidazolidine and triethylamine in dichloromethane (240 mL). The reaction mixture is stirred at room temperature overnight. Water is added and the phases are separated. The organic layer is washed with water and a saturated aqueous NaCl solution, then dried over Na2SO4 and evaporated to separate tert-butyl pyrrolidine-1,3-carboxylate. The isolated product can then be reacted with 4-vinylbenzylamine in tetrahydrofuran to provide compound B, which produces the desired ligand (III) compound after acid hydrolysis.

[0179]

[0180] aspect

[0181] In a first aspect, the present disclosure provides a membrane comprising:

[0182] polymers, to which ligands are attached,

[0183] The ligand comprises at least one moiety represented by the following structure:

[0184]

[0185] wherein Q is selected from -CH2-, -N(R)- or CH(N)-, and wherein R is C1-C 20 Hydrocarbyl group.

[0186] In a second aspect, the present disclosure provides a membrane according to the first aspect, wherein the moiety is a guanidine moiety.

[0187] In a third aspect, the present disclosure provides a membrane according to the first aspect, wherein the moiety is an amidine moiety.

[0188] In a fourth aspect, the present disclosure provides the film according to the first aspect, wherein the portion has the following structure:

[0189]

[0190] In a fifth aspect, the present disclosure provides a membrane according to the first or second aspect, wherein the ligand comprises a guanidine moiety linked by a benzyl group having the following structure:

[0191]

[0192] wherein each R is independently selected from hydrogen, C1-C4 alkyl, cyclohexyl and phenyl.

[0193] In a sixth aspect, the present disclosure provides the membrane according to the first aspect, wherein the ligand is a compound having the following structure:

[0194]

[0195] In a seventh aspect, the present disclosure provides a membrane according to the first or second aspect, wherein the ligand is a compound having the following structure:

[0196]

[0197] In an eighth aspect, the present disclosure provides a membrane according to the first or third aspect, wherein the ligand comprises an amidine moiety having the following structure:

[0198]

[0199] In a ninth aspect, the present disclosure provides a membrane according to the first aspect, wherein the ligand is selected from compounds having the following structure:

[0200]

[0201]

[0202] In an eleventh aspect, the present disclosure provides a membrane according to the first aspect, wherein the ligand is selected from the following structures:

[0203]

[0204]

[0205] In a twelfth aspect, the present disclosure provides the membrane according to the first aspect, wherein the ligand comprises the following structure:

[0206]

[0207] In a thirteenth aspect, the present disclosure provides the membrane according to the first aspect, wherein the ligand is selected from polyguanidine.

[0208] In a fourteenth aspect, the present disclosure provides a membrane according to the first aspect, wherein the membrane comprises a porous polymer filtration membrane comprising a polymer material selected from polyamide, polyimide, polysulfone, polyethersulfone, polyolefin, halogenated polymer, or a combination thereof.

[0209] In a fifteenth aspect, the present disclosure provides the membrane of the fourteenth aspect, wherein the polymer material is selected from ultra-high molecular weight polyethylene and poly(tetrafluoroethylene).

[0210] In a sixteenth aspect, the present disclosure provides the membrane according to the first aspect, wherein the filter is capable of reducing the amount of Fe in the aqueous amine solution by at least 50%.

[0211] In a seventeenth aspect, the present disclosure provides a membrane according to the first aspect, wherein the filter is capable of reducing the amount of Fe in the amine by at least 90%

[0212] In an eighteenth aspect, the present disclosure provides a membrane according to the first aspect, wherein the filter is capable of reducing the amount of metals selected from Na, K, Mg, Mn, Cr, Al, Ni, Zn, Ba and Pb present in an aqueous amine solution by at least 50%.

[0213] In a nineteenth aspect, the present disclosure provides a method of removing impurities from a liquid, wherein the liquid comprises at least one amine, the method comprising contacting the liquid with the membrane according to any one of aspects one to eighteen.

[0214] In a twentieth aspect, the present disclosure provides a filter comprising the filtration membrane according to any one of the first to eighteenth aspects.

[0215] In a twenty-first aspect, the present disclosure provides a liquid composition comprising at least one amine and having less than about 1 ppb iron.

[0216] In a twenty-second aspect, the present disclosure provides the liquid composition according to the twenty-first aspect, comprising hydroxylamine having less than 1 ppb iron.

[0217] In a twenty-third aspect, the present disclosure provides the liquid composition of aspect twenty-second, having less than 0.5 ppb iron.

[0218] While several illustrative embodiments of the present disclosure have thus been described, those skilled in the art will readily appreciate that other embodiments may be made and used within the scope of the appended claims. The many advantages of the present disclosure encompassed by this document have been set forth in the foregoing description. However, it should be understood that the present disclosure is in many respects merely illustrative. Of course, the scope of the present disclosure is defined in the language in which the appended claims are expressed.

Claims

1. A porous polymer membrane having attached thereto a ligand, said ligand comprising a moiety selected from the group consisting of: (i) a cyclic guanidine moiety, and (ii) a cyclic amidine moiety.

2. The porous polymer membrane of claim 1, wherein the moiety is a cyclic guanidine moiety.

3. The porous polymer membrane of claim 1, wherein the moiety is a cyclic amidine moiety.

4. The porous polymer membrane according to claim 1, wherein the ligand is a compound having the following structure:

5. The porous polymer membrane according to claim 1, wherein the ligand is selected from compounds having the following structures:

6. The porous polymer membrane according to claim 1, wherein the ligand is selected from the following structures:

7. The porous polymer membrane of claim 1, comprising a polymer material selected from the group consisting of polyamide, polyimide, polysulfone, polyethersulfone, polyolefin, halogenated polymer, or combinations thereof.

8. The porous polymer membrane of claim 1, wherein the polymer material is selected from ultra-high molecular weight polyethylene and poly(tetrafluoroethylene).

9. The porous polymer membrane of claim 1, wherein the filter is capable of reducing the amount of Fe in an aqueous amine solution by at least 50%.

10. The porous polymer membrane of claim 1, wherein the filter is capable of reducing the amount of Fe in the amine by at least 90%.

11. The porous polymer membrane of claim 1 , wherein the filter is capable of reducing the amount of a metal selected from the group consisting of Na, K, Mg, Mn, Cr, Al, Ni, Zn, Ba, and Pb present in an aqueous amine solution by at least 50%.

12. A method of removing impurities from a liquid, wherein the liquid comprises at least one amine, the method comprising contacting the liquid with the porous polymer membrane according to claim 1.

13. A filter comprising the porous polymer membrane according to claim 1.

14. The porous polymer membrane of claim 1, wherein the ligand is attached to the porous polymer membrane via a benzyl group.

15. The porous polymer membrane of claim 1, wherein the ligand is attached to the porous polymer membrane by (i) cross-linking a coating or (ii) grafting from the porous polymer membrane.

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