Ligand-modified filter and methods for reducing metals from liquid compositions

Abstract

To provide filter materials for removing metals or metal ions from fluid.SOLUTION: A filter material comprises a porous polymeric filter material having a crosslinked coating, the coating comprising a polycarboxyl ligand having at least two carboxylic acid groups, wherein the polycarboxyl ligand has the following partial structure [where x represents an integer from 1 to 6, n is equal to 2 or 3, and z represents a valence of 0 or +1].SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The following description relates to ligand-modified articles, such as filter membranes, and methods of using the articles to remove metals from liquid compositions. [Background technology]

[0002] Filters are used to remove unwanted materials from useful fluid streams and have become an important feature in a wide variety of industrial technologies. Fluids that are treated to remove unwanted materials include water, liquid industrial solvents and process fluids, industrial gases used in manufacturing or processing, and liquids for medical or pharmaceutical applications. Unwanted materials removed from fluids include impurities and contaminants, such as particles, microorganisms, and dissolved chemical species. Specific examples of filter applications include their use with liquid materials for semiconductor and microelectronic device manufacturing.

[0003] Filters can remove unwanted materials by a variety of different methods, such as size exclusion, or chemical and / or physical interactions with materials. Some filters are defined by structural materials that provide a porous architecture to the filter, and the filter can capture particles of a size that cannot pass through the pores. Some filters are defined by the ability of the structural materials of the filter, or the chemistry associated with the structural materials, to bind and interact with materials passing through the filter. For example, the chemical characteristics of the filter can allow it to bind unwanted materials from the stream passing through the filter, capturing these unwanted materials, such as through ionic, coordination, chelation, or hydrogen bonding interactions. Some filters can utilize both size exclusion and chemical interaction characteristics to remove materials from the stream being filtered.

[0004] In some cases, to perform the filtering function, the filter includes a filter membrane, which is responsible for removing unwanted materials from the fluid passing through it. The filter membrane may be in the form of a flat sheet, which may be wound (e.g., spirally), flat, pleated, or disk-shaped, as desired. The filter membrane may alternatively be in the form of hollow fibers. The filter membrane may be housed or otherwise supported within a housing such that the fluid being filtered enters through the filter inlet and must pass through the filter membrane before passing through the filter outlet.

[0005] The removal of ionic materials, e.g., dissolved anions and cations, from solutions is important in many industries, e.g., the microelectronics industry, where very low 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 materials, e.g., metal ions, from liquid compositions used in device fabrication. Metal-containing materials can be found in different types of liquids used in microelectronics fabrication.

[0006] Various unsolved technical challenges remain for the removal of metal-containing materials from fluids. In the case of purification of photochemicals, particularly complex multi-component compositions containing solvents, resist polymers, quenchers, surfactants, and photoacid generators (PAGs), there is a demand for greater selectivity for removing specific metal contaminants in the presence of such other components in the formulation. Summary of the Invention

[0007] The present disclosure provides various inventive embodiments directed to the removal of metal contaminants from fluids, as well as ligand-modified filter materials useful for carrying out such methods. The filters and methods of the present disclosure are particularly effective in removing metals from liquid compositions. The filtered liquid compositions having significantly reduced metal content can be used in microelectronics manufacturing processes, for example as liquids for removing photoresist or liquids used in acid etching. The ligand-modified filters, such as ligand-modified porous membranes, can be configured for use in microelectronics manufacturing systems and can be utilized within the systems as a point of use function for metal removal of liquids entering the systems.

[0008] Accordingly, one aspect of the present disclosure provides a method for removing one or more metals or metal ions from a liquid composition, comprising: contacting a filter material having at least one polycarboxyl ligand covalently bonded to the filter material via a bond other than a carboxyl bond with a liquid composition comprising one or more metals or metal ions; Reducing the amount of one or more metals or metal ions in the liquid composition; In other words, the polycarboxyl pendant groups or ligands are not attached to the filter material, for example, via ester, amide, or imide bonds. Upon contact, the filter reduces the amount of one or more metals or metal ions in the liquid composition.

[0009] In one embodiment, the polycarboxyl ligand is derived from iminodiacetic acid, ethylenediaminetetraacetic acid, 1,2-cyclohexanediamine-N,N,N',N'-tetraacetic acid, nitrilotriacetic acid, or iminodisuccinic acid.

[0010] A "polycarboxyl ligand" in this disclosure refers to a chemical entity having at least two carboxylic acid groups. In one embodiment, such a compound also has at least one secondary or tertiary amine moiety. In one embodiment, such a ligand has the following moiety: TIFF2025072377000002.tif23170 [wherein x is an integer from 1 to 6, n is equal to 2 or 3, and z represents either a valence of 0 or +1] In another embodiment, such a ligand has the following substructure: TIFF2025072377000003.tif23170. Specific examples of such polycarboxyl ligand compounds include those derived from iminodiacetic acid, ethylenediaminetetraacetic acid, iminodisuccinic acid, nitriloacetic acid, etc. In certain embodiments, this type of ligand is derived from iminodiacetic acid.

[0011] Thus, in another embodiment, the present invention provides a method for manufacturing a microelectronic device, the method comprising carrying out filtration of a liquid composition with a filter material comprising a polycarboxyl ligand as described herein, the metal or metal ion depleted liquid composition being subsequently contacted with a microelectronic article in the manufacturing process of the microelectronic device.

[0012] In another embodiment, the present disclosure provides a porous polymeric filter membrane having polycarboxyl ligands, the membrane being configured for use in conjunction with a microelectronics manufacturing system for providing a metal or metal ion depleted liquid composition to a microelectronic device. The porous polymeric filter membrane can be disposed within a housing, such as a cartridge, and in fluid communication with a fluid source used in semiconductor manufacturing, such as a supply vessel containing a basic or acidic aqueous composition. In certain embodiments, the porous polymeric filter membrane is a component of the microelectronics manufacturing system.

[0013] Experimental studies related to the present disclosure have revealed that, compared to conventional ion exchange ligands, filter materials having immobilized or pendant polycarboxyl ligands as described herein provide superior reduction of metal and / or metal ion contaminants in fluid process streams. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is an exemplary cross-sectional view of a filter having a single porous membrane with a ligand of the present disclosure. [Diagram 2] Metal reduction in photoactive generator (PAG) solutions comparing Purasol™ SN filters, Purasol™ SP filters (both from Entegris, Inc.), and 0.2 μM UPE membrane modified with iminodiacetic acid derivatives. [Diagram 3] FIG. 1 shows the sensitivity shift of photoresist formulations containing PAG solutions comparing Purasol™ SN filters, Purasol™ SP filters (both from Entegris, Inc.), and 0.2 μM UPE membrane modified with iminodiacetic acid derivatives. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The present disclosure describes various embodiments of a method for removing metal contaminants from a fluid, in which the ligand of the filter material has a polycarboxyl ligand. A fluid composition can be passed through the ligand-modified filter material to effectively remove metal contaminants to a level suitable for a desired application. One application in which the ligand-modified filter material of the present disclosure can be used is semiconductor manufacturing, for example, for the purification of metals from solutions used in etching and cleaning semiconductor materials. Given the selectivity of their purification capabilities, the ligand-modified filter materials are particularly useful in photolithography in general, and in extreme ultraviolet lithography (EUV) practices, as well as immersion, in particular.

[0016] The filter material to which the polycarboxyl ligand is attached can be made of any suitable material or combination of materials. For example, exemplary filter materials can include one or more polymers, metals, ceramics, or natural products. Furthermore, in some embodiments, the material of the filter can have a suitable chemistry for attachment to the polycarboxyl ligand. Alternatively, the surface of the filter material can be modified to chemically react with the polycarboxyl ligand or their derivatives.

[0017] "Filter" refers to an article having a structure that includes a filter material. For example, filters can take any form useful in filtration processes, including in the form of porous membranes, beads, tubes, etc., and can be made from one or more filter materials, such as polymers, including synthetic and natural polymers, such as alloys, natural products, ceramics, metal-containing materials such as carbon fibers, etc. In some embodiments, polycarboxyl ligands can be attached to the filter material.

[0018] The filter may take any desired form suitable for the filtration application. The material forming the filter may be a structural component of the filter itself, providing the filter with a desired architecture. The filter may be porous or non-porous and may be of any desired shape or configuration. The filter itself may be a unitary article or may be represented by a plurality of individual articles, such as particles (e.g., resin beads).

[0019] In some embodiments, the filter material is formed from polymeric materials, a mixture of different polymeric materials, or polymeric and non-polymeric materials. The polymeric materials forming the filter may be crosslinked together to provide a desired degree of integrity to the structure of the filter.

[0020] Polymeric materials that may be used to form the filter material of the disclosed filters include hydrophobic polymers. In some embodiments, the filter material includes a polyolefin or a halogenated polymer. 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 more specific embodiments, the filter material includes ultra-high molecular weight polyethylene (UPE). UPE filter materials, such as UPE membranes, have a molecular weight of, for example, about 1×10 6 ~9×10 6 Da, or 1.5 × 10 6 -9×10 6 such as in the Da range, about 1 × 10 6 Typically formed from resins having a molecular weight (weight average molecular weight) greater than Da. Crosslinking between polyolefin polymers such as 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 azoester compounds (e.g., 2,2'-azo-bis(2-acetoxy-propane)). Exemplary halogenated polymers include polytetrafluoroethylene (PTFE), polychlorotrifluoro-ethylene (PCTFE), fluorinated ethylene polymer (FEP), polyhexafluoropropylene, and polyvinylidene fluoride (PVDF).

[0021] In other embodiments, the filter material comprises a polymer selected from the group consisting of polyamide, polyimide, polysulfone, polyethersulfone, polyarylsulfone polyamide, polyacrylate, polyester, nylon, cellulose, cellulose ester, polycarbonate, or combinations thereof.

[0022] In some implementations, the polymeric material can be modified to facilitate the modification of the filter material with polycarboxyl ligands. In certain embodiments, the polycarboxyl ligands contain at least one secondary or tertiary amine group that can facilitate attachment to the polymeric filter material. If the polymeric material is not inherently amine-reactive, the polymeric material can be modified, such as by halogenation or haloalkylation, to provide a surface reactive chemistry for attachment of the polycarboxyl ligand. As described herein, however, the polycarboxyl ligands are covalently attached to the filter material via bonds other than carboxyl bonds, such as ester bonds, amide bonds, and imide bonds.

[0023] In some modes of implementation, the polymeric material of the filter is halogenated to provide amine reactive sites. For example, polyethylene can be chlorinated by reacting chlorine gas, which may be diluted with an inert gas, with solid polyethylene powder at temperatures above 50° C. (see, e.g., U.S. Pat. No. 2,928,819, incorporated herein by reference).

[0024] In another embodiment, the polymer of the filter material can be haloalkylated, for example, chloromethylated. Chloromethylation is known as a technique used to modify polymers, and generally uses chloromethylation reagents (e.g., bischloromethyl ether (BCME); chloromethyl methyl ether (CMME); formaldehyde / methanol / hydrogen chloride / chlorosulfonic acid). To modify the polymer, Lewis acids and Friedel-Crafts catalysts, such as zinc chloride, zinc oxide, or iron(III) chloride, can be used with chloromethylation reagents at high temperatures (see, for example, US2003 / 0018091 (Pafford et al.) and WO2008 / 144115 (Harris et al.)). To provide the ligand of the present disclosure on the filter, the haloalkyl group of the haloalkyl-modified filter material can be reacted with polycarboxyl, thereby covalently binding the ligand to the surface of the filter material.

[0025] In another mode of implementation, polycarboxyl ligands can be attached to the filter material via attachment with a reactive crosslinking coating. For example, the filter material can be coated with a composition that includes a monomeric, oligomeric, or polymeric material that reacts with amines; such amine-reactive polymers include poly(vinylbenzyl chloride), poly(epichlorohydrin), and epoxy resins. Other examples of reactive monomers include N,N'-methylenebis(acrylamide), triethylene glycol dimethacrylate, triethylene glycol diacrylate, and ethylene glycol divinyl ether. The coated filter material can then be crosslinked, and the remaining reactive sites can be used to attach the desired ligand. For example, poly(vinylbenzyl chloride) can be dissolved in a suitable solvent, dried onto a porous membrane, and crosslinked with a diamine, polyamine, or any other multifunctional reactive crosslinker, followed by attachment of the polycarboxyl ligand. Using a similar method, crosslinking and ligand attachment can occur simultaneously. Alternatively, amine reactive polymers can be crosslinked (free radically) via irradiation or through the use of crosslinking photoinitiators, followed by attachment of amine-containing ligands.

[0026] In another mode of implementation, ligand attachment can occur prior to coating onto the filter material. For example, a polycarboxyl-functionalized polymer can be prepared by reacting a polycarboxyl ligand or a reactive derivative thereof with a polymeric material having functional groups reactive with the amines of the ligand, such as poly(vinylbenzyl chloride). The filter material can then be coated with the resulting polycarboxyl ligand-modified polymer and dried. Any cross-linking technique can also be used.

[0027] In another mode of implementation, the filter material can be coated with the desired polycarboxyl ligand through cross-linking of the monomer. For example, the desired polycarboxyl ligand can be present in the form of a reactive monomer having an acrylamide, vinyl or other suitable unsaturated group with epoxy functionality suitable for reacting with amines. Such compounds can be prepared, for example, by the reaction of iminodiacetic acid with glycidyl acrylate, glycidyl methacrylate or allyl glycidyl ether. Thus, in the case of the reaction of iminodiacetic acid with allyl glycidyl ether, the resulting compound has both two free carboxyl groups and a pendant allyl group. The polycarboxyl group-containing monomer can be added to a monomer blend containing a bifunctional monomer, such as N,N'-methylenebisacrylamide. These monomer formulations may also contain a photoinitiator, such as, for example, OMNIRAD2959 (1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one). Once the film is immersed in the resulting monomer solution, the film can be irradiated (UV light, e-beam, gamma radiation, etc.) to form a crosslinked coating with the desired polycarboxyl ligands incorporated into the coating (see, for example, WO 2017 / 205722 (Jaber et al.)).

[0028] In another mode of implementation, the desired polycarboxyl ligand can be attached to the filter material via grafting from a membrane. "Grafting" in this context can be achieved by irradiation of the filter material in the presence of a photoinitiator and an unsaturated monomer containing the desired polycarboxyl ligand (see, for example, WO 2016 / 081729 A1 (Jaber et al.)). In another mode of implementation, the filter material can be attached to the desired polycarboxyl ligand via grafting from a membrane using irradiation with electron beam or gamma radiation. Grafting using irradiation with electron beam or gamma radiation can be achieved using a technique known as pre-irradiation grafting or simultaneous irradiation grafting.

[0029] In another implementation mode, filter material can be embedded in resin particles to form hybrid particle / membrane filter material. For example, porous poly(styrene-co-divinylbenzene) resin particles with desired polycarboxyl ligands attached can be introduced into the polymer mixture used for membrane extrusion or membrane casting. Using this method, the resulting porous polymer membrane will have embedded porous particles with desired polycarboxyl ligands attached. In some embodiments, the resulting membrane can have a fixed particle-retaining membrane located downstream of the porous particle-containing membrane (see, for example, US 2009 / 0039019A1 (Raman)).

[0030] The concentration of the polycarboxyl ligand can be sufficient to allow the ligand to be immobilized 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 useful technique, such as, for example, spraying, dipping, immersing, etc., of the filter material solution. Desirably, the entire surface of the filter can be contacted with the solution, such as, for example, all the internal surfaces of a porous filter membrane. If necessary, the applying step can include manipulation of the filter material, such as, for example, rolling or squeezing the porous filter medium to wet the entire surface of the porous filter.

[0031] In various examples of the methods and devices described herein, the filter comprises a porous filter membrane having polycarboxyl ligands attached to the material forming the membrane. As used herein, a "porous filter membrane" is a porous solid that includes porous (e.g., microporous) interconnecting passages that extend from one surface of the membrane to the opposite surface of the membrane. The passages generally provide a tortuous tunnel or passage through which the liquid to be filtered must pass. Metal species that are small enough in size to pass through the pores of the membrane can be trapped on the membrane by interaction with the polycarboxyl ligands, e.g., chelating interactions between the ligand and the metal. This is referred to as a non-sieving filtration mechanism.

[0032] The filter may also function to prevent any particles (e.g., metal-containing particles) present in the liquid that are larger than the pores from entering the microporous membrane, or may function to trap the particles within the pores of the microporous membrane (i.e., in this case, they are removed by a sieving filtration mechanism). The liquid to be treated passes through the membrane and may become a flow-through fraction having a reduced amount of metal, e.g., a reduced amount of ionic metal species, a reduced amount of metal-containing particulates, or both.

[0033] Thus, porous polymeric membranes having polycarboxyl ligands attached thereto can remove metal and metal ion contaminants in a solution passing through the membrane, as well as any material whose size is too large to pass through the pores of the membrane.

[0034] The porous membrane of the present disclosure can be described by referring to one or more membrane properties.The exemplary porous polymeric filter membrane as described herein is characterized by physical characteristics including pore size, bubble point and porosity.For example, the membrane can be described by considering bubble point, which is commonly used to reflect pore size.

[0035] The bubble point method is based on the premise that for a particular fluid and pore size with constant wetting, the pressure required to force a bubble into 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 method for measuring bubble point includes wetting the membrane, applying pressure to the membrane, and then measuring the pressure point at which a bubble is released from the top surface of the membrane. A standard method for bubble point is published in American Society for Testing and Materials Standard (ASMT) Method F316. In certain embodiments of the present disclosure, the porous polymeric membrane can have a bubble point at a temperature of 20 to 25 degrees Celsius in the range of about 2 psi to about 400 psi, about 4 psi to about 200 psi, or about 4 psi to about 160 psi, when ethoxy-nonafluorobutane (HFE-7200) is used as the wetting solvent.

[0036] Alternatively, pore size may be measured by known techniques, such as, for example, Mercury Porosimetry (MP), Scanning Electron Microscopy (SEM), Liquid Displacement (LLDP), or Atomic Force Microscopy (AFM).

[0037] The porous polymeric filter membrane may have any pore size that makes the filter membrane effective to function as a filter membrane. The pore size may be correlated with bubble point measurements. In some embodiments, the porous membrane may have an average pore size ranging from about 0.001 microns to about 5 or 10 microns, such as 0.01 microns to 0.8 microns. The average pore size may be selected based on one or more factors, including fluid flow rate, pressure, pressure drop considerations, viscosity considerations, impurities (e.g., amount of metal impurities) in the liquid to be treated, and particle size of any impurities.

[0038] Additionally, the present disclosure contemplates the use of polymeric membranes with near-uniform pore sizes resulting from higher pore symmetry, as well as membranes with non-uniform pore sizes (variable pore diameters) resulting from pore asymmetry. The pores can be isotropic or anisotropic, stripped or unstripped, symmetric or asymmetric, and any combination thereof.

[0039] The porous polymeric filter layer as described may have any porosity that allows the porous polymeric filter layer to be effective as described herein.Exemplary porous polymeric filter layers may have relatively high porosity, for example, at least 60, 70 or 80%.As used herein, and in the art of porous bodies, the "porosity" of a porous body (sometimes also called porosity) is a measure of the void (i.e., "empty") space within the body as a percentage of the total volume of the body, and is calculated as the ratio of the void volume of the body to the total volume of the body.An object with 0% porosity is completely solid.

[0040] The filter membranes described herein may be useful in any type of industrial process that requires high purity liquid materials as inputs. Non-limiting examples of such processes include processes for preparing microelectronic or semiconductor devices, and a specific example is a method for filtering liquid processing materials used in semiconductor photolithography. The filters of the present disclosure may remove metal ions and metal-containing particles from processing liquids or solvents used in preparing microelectronics or semiconductors, and may remove other non-metallic particulate materials by the sieving action of the membrane. The filters of the present disclosure are surprisingly selective in removing undesired metal ions from such liquid materials, while not affecting other materials typically found in more complex photoresist compositions, such as solvents, resist polymers, quenchers, surfactants, and photoacid generators (PAGs). This selectivity property may be expressed as a "sensitivity shift." The benefit observed with the filter media described herein is that there is little sensitivity shift, i.e., no change in width of features on silicon wafers, when comparing features formed from resist formulations containing PAGs that have been filtered through the metal removal filters described herein with those formed from resist formulations containing unfiltered PAGs. TM Filtration systems may remove metal contaminants, but may also bind PAG molecules, resulting in a sensitivity shift. The ligand-modified filter media described herein exhibit greater selectivity in the extent to which they remove metal contaminants without binding PAG molecules, thereby resulting in a cleaner solution (i.e., a solution with reduced metal contaminants) with a greatly reduced sensitivity shift.

[0041] The porous membrane of the present disclosure can be of any desired geometric configuration suitable for use in a system for reducing metal or metal ion contaminants in a fluid stream. 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 in the form of a flat sheet, a corrugated sheet, a pleated sheet, and a hollow fiber, among others.

[0042] The described porous polymeric membranes can be in the form of sheets or hollow fibers having any useful thickness, such as, for example, thicknesses ranging from 20 microns to 400 microns (eg, 40 or 80 microns to 100 or 200 microns).

[0043] The polycarboxyl ligands can also be immobilized on a filter material in the form of filter particles. The filter particles are called "resins" or "polymeric resins" and can be formed by precipitation, grinding or milling to form resin particles having a particle size ranging from about 5 microns to about 600 microns, or from about 8 microns to about 75 microns, or from about 8 microns to about 20 microns. However, the particle size distribution can vary, and in some embodiments, it can be less than about ±25%, and in other embodiments, it can be less than about ±10%.

[0044] 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, brackets, clips, webs, nets, cages, etc. In some structures, at least a portion of the support structure may be a housing as described herein.

[0045] The porous membrane may be provided as part of a filter assembly that includes a housing. For example, the housing is configured to be fluid-sealed (apart from the inlet and outlet ports), to hold a volume of liquid, and to allow liquid to pass through the membrane. The housing may be used to form a larger filter structure, such as a filter assembly (single or multi-layer) or a filter cartridge for use in a filtration system. The filtration system places the filter membrane in the filter housing, for example as part of a filter assembly or as part of a filter cartridge, such that the filter membrane is exposed to the flow path of the liquid chemical so that at least a portion of the liquid chemical flow passes through the filter membrane, thereby removing an amount of impurities or contaminants from the liquid chemical. The structure of the filter assembly or filter cartridge may include one or more various additional materials and structures that support the filter membrane within the filter assembly or filter cartridge to allow fluid to flow from the filter inlet through the filter material (e.g., filter membrane) and through the filter outlet. The filter membrane supported by the filter assembly or filter cartridge can be of any useful shape, such as, for example, a pleated cylinder, a cylindrical pad, one or more non-pleated (flat) cylindrical sheets, a pleated sheet, among others.

[0046] Embodiments of the present disclosure include methods and filter devices for removing metal contaminants from a liquid, such as a base-containing or acid-containing liquid, which is passed through a porous polymeric membrane having polycarboxyl ligands. As shown in FIG. 1, the present disclosure provides a filter 100 including a porous polymeric membrane 102. The porous polymeric membrane 102 includes polycarboxyl ligands immobilized on the surface of the membrane. The filter 100 can have a housing 104 that provides structure to the filter 100 and seals the interior portion of the filter against fluid. The housing 104 can be of any shape and size, for example, cylindrical, polygonal, etc.

[0047] A portion of the filter may include an inlet port 106 for receiving the metal / metal ion-containing fluid composition to be filtered. The inlet port 106 may be configured to be connected to a fluid supply line. In that case, the inlet port 106 may include a valve, gasket, etc. (not shown) to facilitate connection to the fluid supply. The metal / metal ion-containing fluid composition to be filtered may flow through the inlet port 106 in the direction indicated by arrow 116 and into a headspace 114 within the filter 100 defined by the input-facing surface 124 of the porous polymeric membrane 102, the interior surface of the housing 104, and the input port 106. In an embodiment, the filter may be constructed such that the headspace has a volume that is a desired percentage of the total internal volume of the filter.

[0048] The interior of the filter may include a porous membrane in any suitable configuration or arrangement, with FIG. 1 depicting a porous polymeric membrane 102 having a disk-like architecture (cross-section shown). A side 122 of the porous polymeric membrane 102, such as the periphery of the membrane, may be in contact with the interior surface of the housing 104. The porous polymeric membrane 102 may also have an input-facing side 124 that initially contacts the metal / metal ion-containing fluid, and an output-facing side 126 through which the treated fluid with reduced amounts of metal / metal ions flows out. Embodiments of the filter may optionally be described in terms of a range of ratios of the surface area of ​​the input-facing side 124 to the volume of the porous polymeric membrane 102, or the ratio of the surface area to the thickness of the filter.

[0049] The filter 100 also includes one or more features that support the porous polymeric membrane 102 within the filter. Any arrangement for supporting the filter may be used, including one or more separate structural features such as frames, brackets, clips, webs, nets, cages, and the like, or a material such as adhesive may be used to support the membrane. A combination of adhesive and structural support features may be used. In an embodiment, referring to FIG. 1, the filter includes a frame having frame portions 110 and 112, where frame portion 110 contacts the inner surface of the housing 104 and is attached to portion 112. Portion 112 may contact the output-facing surface 124 of the porous polymeric membrane 102 and provide support to the membrane during filtration. Frame portion 112 may have a lattice-like structure to allow the liquid to be filtered to pass freely into the backspace 120 of the filter, providing structural support to the polymeric porous membrane even under increased fluid pressure.

[0050] In use, liquid enters the filter through inlet port 106 in the direction indicated by arrow 116 and then fills the headspace 114 within filter 100. Sufficient fluid pressure is applied to cause the fluid to pass through the porous polymeric membrane at a desired flow rate.

[0051] Exemplary flow rates for porous membranes range from about 0.1 L / min to about 40 L / min, or more preferably from about 5 L / min to about 20 L / min. Alternatively, flow rates for porous membranes can be expressed as the amount of liquid passed per filter area per hour (e.g., liters / m 2 / h=LMH), for example from about 100 LMH / bar to about 30,000 LMH / bar, or more preferably from about 5,000 LMH / bar to about 15,000 LMH / bar.

[0052] In some embodiments, the filter of the present disclosure includes a composite membrane arrangement. For example, a filter with a composite membrane can include two or more filter materials, such as two or more filter articles. For example, a filter can include a first porous polymeric membrane that includes one of the polycarboxyl ligands, and a second filter material that does not include the ligand present in the first porous polymeric membrane (e.g., a different polycarboxyl ligand or some other ligand) or that is different in some way from the first porous polymeric membrane. The second filter material can be in the form of a porous membrane, or it can be in a different form, such as a non-porous form. The second filter material can be made of the same or different polymeric material as the first membrane, and can be either modified or unmodified, such as modified with a ligand (e.g., a polycarboxyl ligand) that is not present in the first membrane.

[0053] In some embodiments, the filter comprises a first porous polymeric membrane comprising a polycarboxyl ligand and a second porous polymeric membrane comprising a different polycarboxyl ligand. In another embodiment, the filter comprises a first porous polymeric membrane comprising a polycarboxyl ligand and a second porous polymeric membrane either without a polycarboxyl ligand or with a different polycarboxyl ligand. In an embodiment, the first and second porous polymeric membranes are constructed from the same or similar polymeric materials and have the same or similar pore sizes. In another embodiment, the first and second porous polymeric membranes are constructed from different polymeric materials and / or have different pore sizes.

[0054] In some embodiments, the porous resin particles having the desired polycarboxyl ligands attached thereto can be in the form of a packed bed and placed upstream of the retention filter. The packed resin bed can be in the form of a mixed particle bed. For example, the porous poly(styrene-co-divinylbenzene) resin particles having the desired polycarboxyl ligands attached thereto can be mixed with the porous poly(styrene-co-divinylbenzene) resin particles having the desired polycarboxyl ligands attached thereto, and the mixture of resin particles can be placed in the upstream packed resin bed if a retention filter. In some embodiments, the downstream retention filter can be a membrane that is surface-modified, hydrophilic, or has ligands attached thereto. In some embodiments, the retention filter can be pleated, spirally wound, or layered, and the porous resin particles can be packed in the flow path upstream of the retention filter.

[0055] The filters of the present disclosure as described may be useful for filtering liquids to remove undesired metal-containing materials (e.g., contaminants or impurities) from the liquid to produce high purity liquids that can be used as materials for industrial processes. In particular, the porous polymeric filter membrane may be useful for removing dissolved and / or suspended metal-containing contaminants from liquids flowing through the membrane using a combination of sieving mechanisms and ligand binding of metal ions. That is, larger metal-containing particles may be captured by the filter due to size restriction according to pore size, and metal ions that may otherwise migrate through the pores are captured by interaction with polycarboxyl ligands immobilized on the membrane.

[0056] Filter materials containing polycarboxyl ligands can be used to remove metals or metal ions from fluids that have levels of those substances that are too high for the desired process.

[0057] Exemplary metals that may be removed from fluids using the ligand-modified filter materials of the present disclosure include alkali metals, which are chemical elements of Group 1 of the periodic table: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs). Another exemplary metal that may be removed from fluids using the ligand-modified filter materials of the present disclosure includes alkaline earth metals, which are chemical elements of Group 2 of the periodic table: beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). Other exemplary metals that may be removed from fluids using the ligand-modified filter material of the present disclosure include transition metals that are elements of Groups 3 to 12 of the periodic table, including, but not limited to, the d-block of the periodic table, including 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 (Pd), silver (Au), cadmium (Cd), tungsten (W) and mercury (Hg). Other exemplary metals that may be removed from fluids using the ligand-modified filter material of the present disclosure include post-transition metals (Groups 13-15), including aluminum (Al), gallium (Ga), indium (In), tin (Sn), thallium (Tl), lead (Pb) and bismuth (Bi). In certain embodiments, the polycarboxyl ligand modified filters described herein preferentially remove substantially all of the iron and zinc from such solutions.

[0058] Metal contaminants may refer to neutral, negatively charged or positively charged metal species and combinations thereof that may exist in equilibrium. The metals may exist in liquids in the form of dissolved ions, suspended charged particles, colloids or other aggregates, and any of these metal forms may be removed from fluids using the ligand-modified filter materials included in the present disclosure. Some metal ions, such as Fe and Al, may exist as oxides in water. These types of ions may form amphoteric colloidal particles or complexes. In basic conditions, such as the basic cleaning solution (SC1), some of the metal ions may exist as hydroxides, oxides, oxyhydroxides and other anions, or any combination thereof. In some fluids, the metal ions may form amphoteric species, which may include one or more of these groups, and which may exist as either cationic or anionic complexes depending on the conditions (pH, temperature, ionic strength) of the fluid.

[0059] Metal ion impurities in various fluids may be detected using ion chromatography, and removal of metal materials from fluids treated with the filters of the present disclosure may also be determined using inductively coupled plasma mass spectrometry (ICP-MS).

[0060] The filter membranes of the present disclosure may be useful in any type of industrial process that requires high purity liquid materials as input. Non-limiting examples of such processes include processes for preparing microelectronic or semiconductor devices, processes for preparing pharmaceutical compositions, and diagnostic (e.g., medical diagnostic) compositions and methods. The methods and filters of the present disclosure may be used in any of these fields.

[0061] A specific example is a method for filtering liquid processing materials used in semiconductor photolithography. Examples of contaminants present in processing liquids or used to prepare microelectronic or semiconductor devices may include metal ions dissolved in the liquid, solid particles suspended in the liquid, and gelled or solidified materials in the liquid (e.g., generated during photolithography). In embodiments, the disclosed methods and filters are used to provide purified, low metal content liquid compositions for front-end cleaning tools used to fabricate the basis of integrated circuits. For example, the disclosed filters can be used to purify cleaning and etching agents, minimize product contamination, and improve process efficiency (such as etch rate). In chemical-mechanical polishing processes, water is used in addition to reagents and abrasive particles.

[0062] In another embodiment, the ligand-modified filter is used to remove metal and metal ion contaminants from organic solvents. Some specific non-limiting examples of solvents that can be filtered using the filter membrane as described include n-butyl acetate (nBA), isopropyl alcohol (IPA), 2-ethoxyethyl acetate (2EEA), xylene, cyclohexanone, ethyl lactate, isopentyl ether, methyl-2-hydroxyisobutyrate, methyl isobutyl carbinol (MIBC), methyl isobutyl ketone (MIBK), isoamyl acetate, undecane, propylene glycol methyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), and a mixture of propylene glycol monomethyl ether (PGME) and PGMEA (7:3 mixture ratio, surface tension of 27.7 mN / m).

[0063] For example, in some embodiments, a solvent is obtained having a greater amount of metal ions and / or metal-containing impurities than is desired for the intended application for forming integrated circuits, such as a cleaning solvent or a solvent for resist stripping in lithography. For example, metal impurities may be present in the solvent in a total amount of greater than 0.001 μg / L (1,000 parts per trillion (ppt)), greater than 0.005 μg / L (5,000 ppt), greater than 0.01 μg / L (10,000 ppt), or greater than 0.05 μg / L (50,000 ppt). The solvent is then passed through a filter containing a polycarboxyl ligand to remove the metal contaminants and provide a filtered solvent having a lower amount of metal than that in the starting solvent. In modes of operation, the filters of the present disclosure may remove any one or more metals in an amount of about 25% (wt) or more, about 30% (wt) or more, about 35% (wt) or more, about 40% (wt) or more, about 45% (wt) or more, about 50% (wt) or more, about 55% (wt) or more, about 60% (wt) or more, about 65% (wt) or more, about 70% (wt) or more, about 75% (wt) or more, about 80% (wt) or more, about 85% (wt) or more, about 90% (wt) or more, or about 95% (wt) or more from the starting solvent.

[0064] The solvent being treated to remove metal contaminants may be filtered under desired conditions, such as to enhance removal of metal contaminants from the fluid stream. In some modes of implementation, the solvent is filtered at a temperature of about 160° C. or less, 120° C. or less, or 80° C. or less.

[0065] Passing the solvent through the porous membrane containing the polycarboxyl ligand is not limited to any particular flow rate, so long as essentially flux-independent removal of metal impurities is achieved and a pressure drop useful for the application is provided. The area of ​​the porous membrane used can be selected to provide the device with an acceptable pressure drop and essentially flux-independent ligand binding for the flow rate and process requirements of the application. In various embodiments, the membrane area is about 0.25 cm 2or more, and each membrane may be of a specific or fixed area that is used to determine the pressure drop to meet the needs of the application.

[0066] In some implementations, a filter including the porous membrane of the present disclosure may remove metal-containing or other particles from a fluid stream. Particle retention may be assessed by measuring the number of test particles removed from the fluid stream by a membrane placed in the fluid stream. In one method, a 0.1% Triton containing 8 ppm polystyrene particles (Fluoro-Max, 0.025 μm green fluorescent polymeric microparticles available from ThermoFisher Scientific) in an amount sufficient to achieve 0.5, 1, and 2% monolayer coverage is used. TM Particle retention can be measured by passing an aqueous feed solution of X-100 (available from Dow) through the membrane at a constant flow rate of 7 milliliters per minute and collecting the permeate. The polystyrene particle concentration in the permeate can be calculated from the absorbance of the permeate. Particle retention is then calculated using the following equation: TIFF2025072377000004.tif21170

[0067] Furthermore, the filter membrane as described may be characterized by the flow rate or flux of liquid flow through the filter membrane. The flow rate must be high enough so that the filter membrane is efficient and effective in filtering the flow of fluid through the filter membrane. The flow rate, or alternatively considered, the resistance to liquid flow through the filter membrane, may be measured by considering the flow rate or residence time (which is the reciprocal of the flow rate). The filter membrane as described herein, including polycarboxyl ligands, may have, in certain embodiments, a relatively short residence time, e.g., in combination with a relatively high bubble point, and have good filtration performance (e.g., as measured by particle retention). Examples of useful or preferred residence times may be less than about 8,000 sec / 500 mL, e.g., less than about 4,000 sec / 500 mL, less than about 2,000 sec / 500 mL, less than about 1,000 sec / 500 mL, less than about 500 sec / 500 mL, or less than about 200 sec / 500 mL.

[0068] The water retention time of the membrane can be determined by cutting the membrane into a 47 mm disk, wetting it with water, and then placing the disk in a filter holder attached to a reservoir for holding a fixed amount of water. The reservoir is connected to a pressure regulator. Water flows through the membrane under a differential pressure of 14.2 psi (pounds per square inch). After equilibrium is reached, the time for 500 mL of water to flow through the membrane is recorded. EXAMPLES

[0069] Example 1 Preparation of 0.2 μm pore size UPE membrane with IDA ligand

[0070] A monomer solution was prepared by combining 3.5% IDA (iminodiacetic acid), 3% allyl glycidyl ether, 5% sodium hydroxide, and 88.5% deionized water. The monomer solution was heated at 45°C overnight with gentle stirring to obtain a solution containing vinyl iminodiacetic acid monomer. A UV-active IDA coating solution was then prepared by adding 0.22% photoinitiator IRGACURE® 2959, and 1.45% crosslinker N,N´-methylenebis(acrylamide) to the vinyl IDA monomer-containing solution and mixing at room temperature until a homogenous solution was obtained.

[0071] A 47 mm disk of 0.2 μm pore size UPE (ultra high molecular weight) membrane, available from Entegris, was wetted with an IPA solution for 25 seconds, exchanged into deionized water, and submerged in the UV-activated IDA coating solution. The membrane disk was removed and placed between polyethylene sheets, and excess liquid and air were expelled by applying pressure with a rubber roller. The polyethylene sheets containing the 0.2 μm pore size UPE membrane imbibed with the UV-activated IDA coating solution were exposed to UV by transporting them through a Fusion UV Systems broadband UV at 10 ft per minute. After emerging from the UV unit, the resulting IDA ligand-coated membrane was removed from the polyethylene sheet and immediately washed with deionized water. The IDA ligand-coated membrane was then further washed by submerging it in methanol for 5 minutes, and finally, dried on a restraining holder in an oven at 65°C for 10 minutes.

[0072] Example 2 A membrane disk prepared according to Example 1 was cleaned using the following process. First, a 47 mm membrane disk was placed in a clean 30 ml PTFE vial (Savillex) and the membrane was wetted with 20 mL of IPA (isopropanol Gigabit®, KMG) for 1 minute and the IPA was decanted off. Next, the membrane was exposed to 20 mL of a 70% IPA / 10% HCl (hydrochloric acid 37% Gigabit®, KMG) mixed solution and gently agitated for 1 hour. After 1 hour, the 70% IPA / 10% HCl solution was decanted off. Next, the membrane was washed and exchanged into deionized water (DIW) multiple times and the DIW was decanted off. Next, the membrane was exposed to an additional 20 mL of 70% IPA / 10% HCl solution and gently agitated for 16 hours. After 16 hours, the 70% IPA / 10% HCl solution was decanted off. The membrane was then washed and exchanged multiple times with DIW, which was then decanted off. The membrane was then washed with 20 mL of 2% NH 4OH (ammonium hydroxide 29% Cleanroom® MB, KMG) and gently stirred for 1 hour. Finally, the membrane was exchanged into DIW multiple times, then into IPA and placed in a convection oven at 70° C. until dry. The cleaned membrane was placed into a fresh clean PTFE bottle.

[0073] Example 3 The IDA-modified UPE membrane disks prepared according to Example 1 and cleaned according to the method described in Example 3 were tested to determine the ability of the membranes to reduce metal concentrations in PGMEA organic liquid (propylene glycol monomethyl ether acetate) under static immersion conditions. The results show that the membranes were effective in removing the metals Al, B, Cr, Fe, Ni, and Zn in PGMEA. Solutions were prepared by adding to PGMEA target metal concentrations of 3000 ppt each of Al, B, Cr, Fe, Ni, and Zn (PlasmaCAL single element calibration standard, SCP Science, Inc. 1000 ppm) as an addition to the metals already present in the solution. 20 mL of the metal-added PGMEA organic liquid was then added to the PTFE bottle containing the IDA-modified UPE membrane disks prepared according to Example 1 and cleaned according to the method described in Example 3. The bottle was capped and rotated for 16 hours. After 16 h, the liquid was decanted into a clean PTFE vial for analysis. The metal concentrations of the metal-spiked PGME organic liquid were measured by ICP-MS before and after exposure to the membrane and used to calculate the metal removal efficiency of the membrane as shown in Table 1. TIFF2025072377000005.tif82170

[0074] Example 4 Purasol TM SN, Purasol TM Metal reduction rates and resulting sensitivity shifts of PAG-containing mixed solvents after filtration using UPE membranes with SP and IDA ligands

[0075] To ensure any contaminating metals are removed, Purasol TMSN, Purasol TM Membrane coupons of 0.2 μm pore size UPE (Example 1) modified with SP and IDA were cleaned. A PGMEA / ethyl lactate mixed solvent containing a photoacid generator (PAG) was obtained and the metal concentration was determined to be 1.2 ppb total metals. Each individual membrane coupon was challenged with the PAG-containing mixed solvent and the filtrate was collected. The metal concentration of the filtrate was measured and the results show that all three membranes were able to remove 100% of the Fe. Purasol was ineffective in removing Zn. TM SN and Purasol TM SP, whereas the 0.2 μm pore size UPE modified with IDA removed 100% of Zn. The 0.2 μm pore size UPE modified with IDA removed >90% of all other metals, whereas Purasol TM SN and Purasol TM SP removed 68.3% and 65.0% of all other metals, respectively. The metal removal results are depicted in Figure 2.

[0076] Each filtered PAG solution was then reconstituted with polymer, quencher, and surfactant and used to coat a silicon wafer that was exposed to UV light and developed to form a pattern. The shift in the critical dimensions of the resulting features relative to patterns generated by a similar formulation of the components but using unfiltered PAG was used to ascertain the effect of filtration on photoacid generation efficiency. As depicted in Figure 3, Purasol TM Filtration of the PAG solution through the SN and SP membranes resulted in measurable changes in pattern size, resulting in sensitivity shifts (%) of 1.6 and -2.8, respectively. Furthermore, as depicted in Figure 3, filtration using an IDA-modified 0.2 μm pore size UPE produced a sensitivity shift of only -0.2%, indicating that filtration using this membrane had minimal impact on the formulation's performance.

[0077] In a first aspect, a filter material comprises a polycarboxyl ligand, the filter material is configured for use in conjunction with a microelectronics manufacturing system to provide a metal or metal ion depleted liquid composition, and the polycarboxyl ligand is covalently bonded to the filter material via at least one bond other than a bond via a carboxyl group.

[0078] In a second embodiment according to the first embodiment, the polycarboxyl ligand has the moiety: TIFF2025072377000006.tif23170 [wherein x is an integer from 1 to 6, n is equal to 2 or 3, and z represents either a valence of 0 or +1] has.

[0079] In a third embodiment according to the first embodiment, the polycarboxyl ligand is derived from iminodiacetic acid, ethylenediaminetetraacetic acid, 1,2-cyclohexanediamine-N,N,N',N'-tetraacetic acid, nitriloacetic acid, or iminodisuccinic acid.

[0080] In a fourth aspect according to any of the first, second or third aspects, the polycarboxyl ligand has the moiety: TIFF2025072377000007.tif23170.

[0081] In a fifth aspect according to any of the first to fourth aspects, the filter material is a porous polymeric filter membrane comprising a polymeric material selected from polyamide, polyimide, polysulfone, polyethersulfone, polyolefin, halogenated polymers, and combinations thereof.

[0082] In a sixth embodiment according to the fifth embodiment, the polymeric material is ultra-high molecular weight polyethylene.

[0083] In a seventh embodiment according to the sixth embodiment, the polymeric material is polytetrafluoroethylene.

[0084] In an eighth aspect, a method of removing one or more metals or metal ions from a liquid composition is disclosed, comprising: contacting a filter material having at least one polycarboxyl ligand covalently bonded to the filter material via a bond other than a carboxyl bond, with a liquid composition comprising one or more metals or metal ions, and reducing the amount of the one or more metals or metal ions in the liquid composition.

[0085] In a ninth embodiment according to the eighth embodiment, the polycarboxyl ligand has the moiety: TIFF2025072377000008.tif23170 [wherein x is an integer from 1 to 6, n is equal to 2 or 3, and z represents either a valence of 0 or +1] has.

[0086] In a tenth embodiment according to the eighth embodiment, the polycarboxyl ligand has the moiety: TIFF2025072377000009.tif23170.

[0087] In an eleventh embodiment according to the eighth embodiment, the polycarboxyl ligand is derived from iminodiacetic acid, ethylenediaminetetraacetic acid, nitriloacetic acid, or iminodisuccinic acid.

[0088] In a twelfth embodiment according to any one of the eighth to eleventh embodiments, the filter material is a porous polymeric filter membrane comprising a polymeric material selected from polyamide, polyimide, polysulfone, polyethersulfone, polyolefin, halogenated polymers, and combinations thereof.

[0089] In a thirteenth aspect according to the twelfth aspect, the polymeric material is ultra-high molecular weight polyethylene.

[0090] In a fourteenth aspect according to the twelfth aspect, the polymeric material is polytetrafluoroethylene.

[0091] In a fifteenth aspect, disclosed herein is a composite membrane comprising a first filter material and a second filter material: an output facing surface of the first filter material is in contact with an input facing surface of the second filter material, and the first filter material or the second filter material has at least one polycarboxyl ligand covalently bonded to the filter material via a bond other than a bond via a carboxyl group; the second filter material is different from the first filter material, and the composite membrane is configured for use in conjunction with a microelectronics manufacturing system to provide a metal or metal ion depleted liquid composition.

[0092] In a sixteenth aspect according to the fifteenth aspect, the polycarboxyl ligand has the moiety: TIFF2025072377000010.tif23170 [wherein x is an integer from 1 to 6, n is equal to 2 or 3, and z represents either a valence of 0 or +1] has.

[0093] In a seventeenth embodiment according to the fifteenth embodiment, the polycarboxyl ligand has the moiety: I have TIFF2025072377000011.tif23170.

[0094] In an eighteenth embodiment according to any one of the fifteenth, sixteenth or seventeenth embodiments, the first filter material, the second filter material, or both, is a porous polymeric filter membrane comprising a polymeric material selected from the group consisting of polyamide, polyimide, polysulfone, polyethersulfone, polyolefin, halogenated polymers, and combinations thereof.

[0095] In a nineteenth embodiment according to the fifteenth embodiment, the first filter material is a porous polymeric filter membrane and the second filter material is polymeric resin particles.

[0096] In a twentieth aspect, disclosed herein is a filter material comprising a porous filter material comprising ultra high molecular weight polyethylene surface coated with a composition comprising a free radical reaction product of (i) a polycarboxyl compound having olefinic groups, and (ii) a monomeric, oligomeric, or polymeric compound having at least one olefinically unsaturated bond.

[0097] In a twenty-first embodiment according to the twentieth embodiment, the polycarboxyl compound is covalently bound to the filter via at least one bond other than via a carboxyl group.

[0098] In a twenty-second embodiment according to the twenty-first embodiment, the polycarboxyl compound having an olefin group is represented by the formula The compound is TIFF2025072377000012.tif39170.

[0099] In a twenty-third embodiment according to the twentieth, twenty-first or twenty-second embodiment, the monomeric, oligomeric or polymeric compound having at least one olefinically unsaturated bond is selected from N,N'-methylenebis(acrylamide), triethylene glycol dimethacrylate, triethylene glycol diacrylate, and ethylene glycol divinyl ether.

Claims

1. 1. A filter material comprising a polycarboxyl ligand, The filter material is configured for use in conjunction with a microelectronics manufacturing system to provide a metal or metal ion depleted liquid composition; and The polycarboxyl ligand is covalently bonded to the filter material via at least one bond other than a bond via a carboxyl group; Filter material.

2. The polycarboxyl ligand has the partial structure: wherein x is an integer from 1 to 6, n is equal to 2 or 3, and z represents a valence of either 0 or +1.

2. The filter material of claim 1 having the following structure:

3. 2. The filter material of claim 1, wherein the polycarboxyl ligand is derived from iminodiacetic acid, ethylenediaminetetraacetic acid, 1,2-cyclohexanediamine-N,N,N',N'-tetraacetic acid, nitriloacetic acid, or iminodisuccinic acid.

4. The polycarboxyl ligand has the partial structure:

4. The filter material of claim 1, 2, or 3, having the following structure:

5. 5. The filter material of any one of claims 1 to 4, wherein the filter material is a porous polymeric filter membrane comprising a polymeric material selected from the group consisting of polyamides, polyimides, polysulfones, polyethersulfones, polyolefins, halogenated polymers, and combinations thereof.

6. 6. The filter material of claim 5, wherein the polymeric material is ultra-high molecular weight polyethylene.

7. 6. The filter material of claim 5, wherein the polymeric material is polytetrafluoroethylene.

8. 1. A method for removing one or more metals or metal ions from a liquid composition, comprising: contacting a filter material comprising at least one polycarboxyl ligand covalently bonded to the filter material via a bond other than a bond via a carboxyl group with a liquid composition comprising one or more metals or metal ions; reducing the amount of one or more metals or metal ions in the liquid composition; The method includes:

9. The polycarboxyl ligand has the partial structure: wherein x is an integer from 1 to 6, n is equal to 2 or 3, and z represents a valence of either 0 or +1.

9. The method of claim 8, comprising:

10. The polycarboxyl ligand has the partial structure:

9. The method of claim 8, comprising:

11. 9. The method of claim 8, wherein the polycarboxyl ligand is derived from iminodiacetic acid, ethylenediaminetetraacetic acid, nitriloacetic acid, or iminodisuccinic acid.

12. 12. The method of any one of claims 8 to 11, wherein the filter material is a porous polymeric filter membrane comprising a polymeric material selected from the group consisting of polyamides, polyimides, polysulfones, polyethersulfones, polyolefins, halogenated polymers, and combinations thereof.

13. The method of claim 12, wherein the polymeric material is ultra-high molecular weight polyethylene.

14. The method of claim 12, wherein the polymeric material is polytetrafluoroethylene.

15. A composite membrane comprising a first filter material and a second filter material, an output facing surface of the first filter material in contact with an input facing surface of the second filter material; the first filter material or the second filter material comprises at least one polycarboxyl ligand covalently bonded to the filter via a bond other than a bond via a carboxyl group; the second filter material is different from the first filter material; and The composite membrane is configured for use in conjunction with a microelectronics manufacturing system to provide a metal or metal ion depleted liquid composition.

16. The polycarboxyl ligand has the partial structure: wherein x is an integer from 1 to 6, n is equal to 2 or 3, and z represents a valence of either 0 or +1.

16. The composite membrane of claim 15, having

17. The polycarboxyl ligand has the partial structure:

16. The composite membrane of claim 15, having

18. 18. The composite membrane of claims 15-17, wherein the first filter material, the second filter material, or both are porous polymeric filter membranes comprising a polymeric material selected from the group consisting of polyamides, polyimides, polysulfones, polyethersulfones, polyolefins, halogenated polymers, and combinations thereof.

19. 16. The composite membrane of claim 15, wherein the first filter material is a porous polymeric filter membrane and the second filter material is polymeric resin particles.

20. (i) a polycarboxyl compound having an olefin group, and (ii) a monomeric, oligomeric, or polymeric compound having at least one olefinically unsaturated bond; a porous polymeric filter material comprising ultra-high molecular weight polyethylene having a surface coated with a composition comprising a free radical reaction product of

21. 21. The filter material of claim 20, wherein the polycarboxyl compound is covalently attached to the filter via at least one bond other than through a carboxyl group.

22. The polycarboxyl compound having an olefin group is represented by the formula 22. The filter material of claim 20 or 21, which is a compound of

23. 23. The filter of claim 20, 21, or 22, wherein the at least one monomeric, oligomeric, or polymeric compound having an olefinically unsaturated bond is selected from N,N'-methylenebis(acrylamide), triethylene glycol dimethacrylate, triethylene glycol diacrylate, and ethylene glycol divinyl ether.

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