Systems and methods for purifying solvents

Abstract

To provide methods of purifying solvents, where the purified solvents can be used for cleaning a semiconductor substrate in a multistep semiconductor manufacturing process.SOLUTION: A method of purifying an organic solvent comprises moving an organic solvent through a first filter to a packaging station in a purification system so as to obtain a purified organic solvent. The first filter comprises a filter housing, and at least one filtration medium within the filter housing. The at least one filtration medium has an average pore size of at most about 5 nm. The purification system comprises the first filter, the packaging station, and a conduit in fluid communication with the first filter and the packaging station. The inner surface of the conduit or filter housing contains a fluoropolymer.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority from U.S. Provisional Application No. 62 / 769,612, filed November 20, 2018, the contents of which are incorporated herein by reference in their entirety.

[0002] Field of Disclosure The present disclosure relates to systems and methods for purifying solvents (e.g., organic solvents), and in particular to systems and methods that can be used to obtain organic solvents having high purity, low on-wafer particle counts, and low on-wafer metal counts. [Background technology]

[0003] Background of the disclosure The semiconductor industry has achieved exponential improvements in the packing density of electronic components, which are due to the continuing reduction in component size, ultimately allowing smaller components to be packed in greater numbers into a given area. These improvements are due in large part to the development of new finer and higher resolution processing technologies.

[0004] In the manufacture of high resolution integrated circuits (ICs), bare or film-coated wafers come into contact with various processing liquids. For example, the fabrication of fine metal interconnects typically involves a procedure in which the substrate is coated with a pre-wetting liquid before being coated with a composite liquid to form a resist film. These processing liquids, which contain unique components and various additives, are known to be a source of contamination of IC wafers.

[0005] It can be assumed that even if only a trace amount of contaminants are mixed into these chemical solutions, such as wafer prewetting solutions or developer solutions, the resulting circuit patterns may have defects. It is known that the presence of metal impurities as little as 1.0 ppt can impair the performance and stability of semiconductor devices. Some types of metal contaminants can deteriorate the oxide properties, cause inaccurate patterns, and impair the electrical performance of semiconductor circuits, which ultimately have a negative impact on the manufacturing yield.

[0006] Impurities, such as metal impurities, particulates, organic impurities, moisture, etc., can be unintentionally introduced into chemical liquids at various stages in the manufacture of the chemical liquids. Examples include impurities present in raw materials, in by-products or residual unreacted reactants produced when the chemical liquids are manufactured, or in foreign matter leached or extracted from the surfaces of manufacturing machines or from containment equipment, reaction vessels, etc. used in transport, storage, or reaction. The reduction or elimination of insoluble and soluble contaminants from these chemical liquids used for the manufacture of high-definition and ultra-fine semiconductor electronic circuits is a fundamental guarantee of the manufacture of defect-free ICs.

[0007] In this regard, it is extremely important to significantly improve and tightly control the standards and quality of chemical liquid manufacturing processes and systems in order to form the high purity chemical liquids necessary for the manufacture of ultra-fine and highly precise semiconductor electronic circuits. Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, the requirement for ultra-high purity chemical liquids and the quality improvement and control of these liquids are very important to form highly detailed integrated circuits. Specific key parameters for quality improvement and control include liquid and on-wafer metal reduction, liquid and on-wafer particle count reduction, on-wafer defect reduction, and organic contaminant reduction. All of these key parameters are shown to be influenced by the necessary provision of a purification system and proper design of the purification process.

[0009] In view of the above, the present disclosure provides a purification system and a method for purifying a solvent (e.g., an organic solvent) using the system, particularly for preparing a solvent intended for semiconductor manufacturing, in which an ultra-high purity solvent is produced by controlling the number of particulates and the amount of metal impurities in the solvent within a predetermined range without producing or introducing unknown and unwanted substances, and thus suppressing the generation of residues and / or particle defects and improving the yield of semiconductor wafers. [Means for solving the problem]

[0010] In one embodiment, the disclosure provides a method for purifying an organic solvent, comprising moving the organic solvent through a first filter in a purification system to a packaging station to obtain a purified organic solvent. The first filter comprises a filter housing and at least one filtration medium within the filter housing, the at least one filtration medium having an average pore size of about 5 nm or less. The purification system comprises the first filter, the packaging station, and a conduit in fluid communication with the first filter and the packaging station, the conduit or an interior surface of the filter housing comprising a fluoropolymer.

[0011] In another aspect, the disclosure provides a method for purifying an organic solvent, comprising passing the organic solvent through a first filter and a second filter to obtain a purified organic solvent, wherein the first filter comprises at least one filtration medium having an average pore size of about 5 nm or less and comprising a polyamide, and the second filter comprises at least one filtration medium having an average pore size of about 5 nm or less and comprising a fluoropolymer.

[0012] In another aspect, the present disclosure provides a system that includes: (1) a first filter including a filter housing and at least one filtration medium within the filter housing, the at least one filtration medium having an average pore size of about 5 nm or less; (2) a reservoir containment station; and (3) a conduit in fluid communication with the first filter and the reservoir containment station, wherein the interior surfaces of the filter housing and the conduit comprise a fluoropolymer.

[0013] In yet another aspect, the disclosure provides a system that includes: (1) a first filter comprising a filter housing and at least one filtration medium within the filter housing, the at least one filtration medium having an average pore size of about 5 nm or less and comprising a polyamide; and (2) a second filter in fluid communication with the first filter, the second filter comprising a filter housing and at least one filtration medium within the filter housing, the at least one filtration medium having an average pore size of about 5 nm or less and comprising a fluoropolymer.

[0014] Implementations may include one or more of the following features.

[0015] In some embodiments, the method of the present disclosure may further include passing the organic solvent through a second filter in fluid communication with the first filter and the vessel containment station and present between the first filter and the vessel containment station, the second filter comprising a filter housing and at least one filtration medium within the filter housing, the at least one filtration medium within the second filter having an average pore size of about 5 nm or less. In some embodiments, the inner surface of the filter housing of the second filter may comprise a fluoropolymer. In some embodiments, the entire second filter may be composed of a fluoropolymer.

[0016] In some embodiments, the at least one filtration medium in the first or second filter comprises a polyamide (e.g., nylon), a polyolefin (e.g., polyethylene), a fluoropolymer (e.g., polytetrafluoroethylene), or copolymers thereof. For example, the at least one filtration medium in the first filter may comprise nylon, and the at least one filtration medium in the second filter may comprise polytetrafluoroethylene.

[0017] In some embodiments, the fluoropolymer in the first filter, the second filter, or the inner surface of the conduit may comprise polytetrafluoroethylene or a copolymer thereof.

[0018] In some embodiments, the first filter may include 1-120 filtration media and the second filter may include 1-30 filtration media.

[0019] In some embodiments, moving the organic solvent through a first filter to a container containment station occurs at a temperature of about 80 degrees Fahrenheit or less.

[0020] In some embodiments, the methods described herein include passing the organic solvent through a heat exchanger to maintain a temperature of the organic solvent at or below about 80 degrees Fahrenheit.

[0021] In some embodiments, the method according to the present disclosure may further include passing the organic solvent through a third filter before passing the organic solvent through the first filter, the third filter comprising at least one filtration medium having an average pore size of about 200 nm or less. In some embodiments, the method according to the present disclosure may further include passing the organic solvent through a fourth filter after passing the organic solvent through the third filter and before passing the organic solvent through the first filter, the fourth filter comprising at least one ion exchange filtration medium. In some embodiments, the method according to the present disclosure may further include passing the organic solvent through a fifth filter after passing the organic solvent through the fourth filter and before passing the organic solvent through the first filter, the fifth filter comprising at least one filtration medium having an average pore size of about 20 nm or less.

[0022] In some embodiments, the method described herein may further include circulating the organic solvent through a recirculation loop that includes a first filter at least twice prior to transferring the organic solvent to a container containment station.

[0023] In some embodiments, the organic solvent comprises cyclohexanone, ethyl lactate, n-butyl acetate, propylene glycol methyl ether, propylene glycol methyl ether acetate, 4-methyl-2-pentanol, or propylene carbonate. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of a purification system employed in a method for purifying an organic solvent according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Detailed Description of the Disclosure As defined in this disclosure, unless otherwise specified, all percentages listed are to be understood as weight percents based on the total weight of the composition. Ambient temperature is defined as a temperature of about 16°C to about 27°C unless otherwise specified. The term "solvent" as used in this disclosure refers to a single solvent or a combination of two or more (e.g., three or four) solvents unless otherwise specified. In this disclosure, "ppm" means "parts per million," "ppb" means "parts per billion," and "ppt" means "parts per trillion."

[0026] Generally, the present disclosure provides systems and methods for purifying solvents (e.g., organic solvents) that may be used as wafer processing solutions (e.g., pre-wetting, developing, rinsing, cleaning, or stripping solutions) or as solvents for semiconductor materials used in semiconductor manufacturing processes.

[0027] Before being subjected to the purification method of the present disclosure, the solvent may contain an undesired amount of contaminants and impurities. After the solvent is treated with the purification method of the present disclosure, a substantial amount of the contaminants and impurities may be removed from the solvent. The solvent before treatment is also referred to as "unpurified solvent" in this disclosure. The solvent before treatment may be synthesized in house or may be commercially available by purchase from a supplier. The solvent after treatment is also referred to as "purified solvent" in this disclosure. The "purified solvent" may contain impurities limited within a predetermined range.

[0028] Generally, the solvent referred to in this disclosure may include at least one (e.g., two, three, or four) organic solvent. Examples of suitable organic solvents include methanol, ethanol, 1-propanol, isopropanol, n-propanol, 2-methyl-1-propanol, n-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, n-hexanol, cyclohexanol, 2-methyl-2-butanol, 3-methyl-2-butanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, and the like. 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 2-ethyl-1-butanol, 2,2-dimethyl-3-pentanol, 2,3-dimethyl-3-pentanol, 2,4-dimethyl-3-pentanol, 4,4-dimethyl-2-pentanol, 3-ethyl-3-heptanol, 1-heptanol, 2-heptanol, 3-heptanol, 2-methyl- 2-Hexanol, 2-Methyl-3-hexanol, 5-Methyl-1-hexanol, 5-Methyl-2-hexanol, 2-Ethyl-1-hexanol, Methylcyclohexanol, Trimethylcyclohexanol, 4-Methyl-3-heptanol, 6-Methyl-2-heptanol, 1-Octanol, 2-Octanol, 3-Octanol, 2-Propyl-1-pentanol, 2,6-Dimethyl-4-heptanol, 2-Nonanol, 3,7-Dimethyl-3-octanol, Ethylene glycol, Propyl Propylene glycol, diethyl ether, dipropyl ether, diisopropyl ether, butyl methyl ether, butyl ethyl ether, butyl propyl ether, dibutyl ether, diisobutyl ether, tert-butyl methyl ether, tert-butyl ethyl ether, tert-butyl propyl ether, di-tert-butyl ether, dipentyl ether, diisoamyl ether, cyclopentyl methyl ether, cyclohexyl methyl ether, bromomethyl methyl ether, α,α-Dichloromethyl methyl ether, chloromethyl ethyl ether, 2-chloroethyl methyl ether, 2-bromoethyl methyl ether, 2,2-dichloroethyl methyl ether, 2-chloroethyl ethyl ether, 2-bromoethyl ethyl ether, (±)-1,2-dichloroethyl ethyl ether, 2,2,2-trifluoroethyl ether, ethyl vinyl ether, butyl vinyl ether, allyl ethyl ether, allyl propyl ether, allyl butyl ether, diallyl ether, 2-methoxypropene, ethyl-1-propenyl ether, cis-1-bromo-2-ethoxyethylene, 2-chloroethyl vinyl ether, allyl-1,1,2,2-tetrafluoroethyl ether, octane, isooctane, nonane, Decane, methylcyclohexane, decalin, xylene, ethylbenzene, diethylbenzene, cumene, sec-butylbenzene, cymene, dipentene, methyl pyruvate, monomethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, methyl methoxypropionate, cyclopentanone, cyclohexanone, n-butyl acetate, γ-butyrolactone, diisoamyl ether, isoamyl acetate, chloroform, dichloromethane, 1,4-dioxane, hexyl alcohol, 2-heptanone, isoamyl acetate, propylene carbonate, and tetrahydrofuran.

[0029] In some embodiments, the solvent is a pre-wetting liquid. Examples of pre-wetting liquids include at least one of cyclopentanone (CyPe), cyclohexanone (CyH), monomethyl ether, propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether (PGEE), propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monopropyl ether (PGPE), and ethyl lactate (EL). In other embodiments, the solvent is a developer solution, such as n-butyl acetate, or a rinse solution, such as 4-methyl-2-pentanol (MIBC).

[0030] In some embodiments, the untreated or unpurified organic solvent may have a purity of about 95% or more (e.g., about 96% or more, about 97% or more, about 98% or more, or about 99% or more). In some embodiments, the treated or purified organic solvent obtained from the method described herein may have a purity of about 99.5% or more (e.g., about 99.9% or more, about 99.95% or more, about 99.99% or more, about 99.995% or more, or about 99.999% or more). "Purity" as referred to in this disclosure refers to the weight percent of the solvent in the total weight of the liquid. The content of the organic solvent in the liquid can be measured using a gas chromatography mass spectrometry (GCMS) instrument.

[0031] In some embodiments, in terms of improving the yield of semiconductor chip manufacturing, the boiling point of the solvents described herein is about 200° C. or less (e.g., about 150° C. or less) or about 50° C. or more (e.g., about 100° C. or more). In this disclosure, boiling point means the boiling point at 1 atmosphere (atm).

[0032] In general, impurities contained in the organic solvent before treatment may include metal impurities, particles, and other impurities such as organic impurities and moisture.

[0033] In the description of the present disclosure, the metal impurities may be in solid form (e.g., metal simplex, particulate metal-containing compounds, etc.). Examples of common metal impurities include heavy metals such as iron (Fe), aluminum (Al), chromium (Cr), lead (Pb), and nickel (Ni), and ionic metals such as sodium (Na), potassium (K), and calcium (Ca). Depending on the type of metal, metal impurities may impair oxide integrity, degrade MOS gate stacks, and reduce device lifetime. In the organic solvent purified by the method described in the present disclosure, the total trace metal content is preferably within a predetermined range of 0 to 300 ppt (e.g., 0 to 150 ppt) by mass.

[0034] In the present disclosure, substances having a size of 0.03 μm or more are referred to as "particles" or "particulates". Examples of particles include dust, dirt, organic solids, and inorganic solids. Particles may also contain impurities consisting of colloidalized metal atoms. The type of metal atom that is easily colloidalized is not particularly limited, and may contain at least one metal atom selected from the group consisting of Na, K, Ca, Fe, Cu, Mg, Mn, Li, Al, Cr, Ni, Zn, and Pb. In the organic solvent purified by the method described in the present disclosure, the total number of particles having a size of 0.03 μm or more is preferably within a predetermined range of 100 or less (e.g., 80 or less, 60 or less, 50 or less, 40 or less, or 20 or less) per ml of solvent. The number of "particles" in a liquid medium should be counted by a light scattering type liquid particle counter, and is called LPC (liquid particle count).

[0035] In the description of this disclosure, organic impurities are different from organic solvents and refer to organic substances contained in an amount of 5000 mass ppm or less based on the total mass of the organic solvent and the liquid containing the organic impurities. Organic impurities may be volatile organic compounds present in the ambient air (even in the atmosphere of a clean room). Some of the organic impurities originate from transportation and storage facilities, and some are present in the raw materials from the beginning. Other examples of organic impurities include by-products and / or unreacted reactants when the organic solvent is synthesized.

[0036] The total content of organic impurities in the purified organic solvent is not particularly limited. From the viewpoint of improving the manufacturing yield of semiconductor devices, the total content of organic impurities in the purified organic solvent may be 0.1 to 5000 ppm by mass (for example, 1 to 2000 ppm by mass, 1 to 1000 ppm by mass, 1 to 500 ppm by mass, or 1 to 100 ppm by mass). The content of organic impurities in the solvent described in the present disclosure can be measured using a gas chromatography mass spectrometry (GCMS) device.

[0037] 1 is a schematic diagram illustrating a purification system configuration according to some embodiments of the present disclosure. As shown in FIG. 1, purification system 10 includes a supply unit 20, a first filtration system 110, a storage tank 130, a second filtration system 120, and a vessel storage station 140, all of which are in fluid communication with each other (e.g., via one or more conduits).

[0038] In general, the supply unit 20 (e.g., a tank) is configured to hold or transport a starting material (e.g., raw or unpurified organic solvent). The starting material can be processed by the purification system 10 to produce or produce a purified organic solvent having a limited number of undesired contaminants (e.g., particulate matter, organic impurities, metal impurities) within a predetermined range. The type of supply unit 20 is not particularly limited, so long as it continuously or intermittently supplies the starting material to other components in the purification system 10. In some embodiments, the supply unit 20 may include a material receiving tank, a sensor such as a level gauge (not shown), a pump (not shown), and / or a valve (not shown) for regulating the flow of the starting material. In FIG. 1, the purification system 10 includes one supply unit 20. However, in some embodiments, multiple supply units 20 may be provided (e.g., in parallel or in series) for each of the various starting materials to be processed by the purification system 10.

[0039] Purification system 10 may include at least one first filtration system 110 and at least one second filtration system 120. Generally, first filtration system 110 performs an initial filtration of the starting material (e.g., crude organic solvent) to remove a majority of impurities and / or particles, and second filtration system 120 performs a subsequent filtration to remove remaining impurities and particulates to obtain an ultra-high purity organic solvent.

[0040] In some embodiments, the purification system 10 may optionally include a temperature control unit 100 for setting or maintaining the temperature of the organic solvent within a particular temperature range so that the organic solvent is maintained at a substantially consistent temperature during the purification process. In the present disclosure, the temperature control unit may include, but is not limited to, a commercially available recirculating heating / cooling unit, a condenser, or a heat exchanger. Also, the commercially available recirculating heating / cooling unit, a condenser, or a heat exchanger may be installed, for example, on the conduit of the purification system 10. The temperature control unit 100 may be configured, for example, between the supply unit 20 and the first filtration system 110. In some embodiments, the temperature control unit 100 may set the temperature of the organic solvent to about 80° F. or less (e.g., about 75° F. or less, about 70° F. or less, about 65° F. or less, or about 60° F. or less) and / or about 30° F. or more (e.g., about 40° F. or more, about 50° F. or more, or about 60° F. or more). In some embodiments, because the pumps used in purification system 10 may generate heat and increase the solvent temperature, purification system 10 may include additional temperature control units (e.g., unit 170 and unit 180 described below) in appropriate locations to maintain the solvent temperature at a predetermined value.

[0041] Referring to FIG. 1, a first filtration system 110 may include an optional temperature control unit 100, a supply port 110a, one or more (e.g., two, three, four, five, or ten) filters 112, an outflow port 110b, an optional recirculation conduit 160h, and one or more optional temperature control units 170 (wherein all of these are in fluid communication with each other (e.g., via one or more conduits)).

[0042] In some embodiments, each filter 112 may include a filter housing and one or more filtration media 114 within the filter housing. For example, the first filtration system 110 shown in FIG. 1 includes three filters (i.e., 112a, 112b, and 112c), each of which includes one or more filtration media 114a, 114b, and 114c. In some embodiments, the filters 112 may not have individual housings, and the one or more filtration media 114 (e.g., 114a, 114b, and 114c) have a non-compartmentalized configuration within the first filtration system 110. In other embodiments, the first filtration system 110 may include other purification modules (not shown) in addition to the one or more filters 112.

[0043] 1, filter 112a may include one or more filtration media 114a, filter 112b may include one or more filtration media 114b, and filter 112c may include one or more filtration media 114c, where filtration media 114a, 114b, and 114c may differ in functionality or characteristics and provide different purification processes. In some embodiments, the particular filtration media 114 (e.g., 114a, 114b, and 114c) contained in each corresponding filter 112 (e.g., 112a, 112b, and 112c) may have the same or similar purification function, physicochemical properties, pore size, and / or materials of construction. In some embodiments, each filter 112 may be independently selected from the group consisting of particle removal filters, ion exchange filters, and ion absorption filters.

[0044] In some embodiments, the filtration medium 114a in the filter 112a may be a particle removal filtration medium for removing relatively large particles from the organic solvent. In some embodiments, the filtration medium 114a may have an average pore size of about 1000 nm or less (e.g., about 800 nm or less, about 600 nm or less, about 500 nm or less, about 400 nm or less, about 200 nm or less, or about 150 nm or less) and / or about 50 nm or more (e.g., about 100 nm or more, about 150 nm or more, about 200 nm or more, or about 250 nm or more). Within the above range, foreign matter such as impurities or aggregates contained in the organic solvent can be reliably removed while preventing clogging of the subsequent filter (e.g., filter 112b, 112c, 122a, or 122b). In some embodiments, the filter 122a may include one, two, three, four, five, six, and seven filtration media 114a.

[0045] Examples of suitable materials for the particle removal filter include fluoropolymers (e.g., polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), or modified polytetrafluoroethylene (MPTFE)), polyamide resins such as nylon (e.g., nylon 6 or nylon 66), and polyolefin resins (including high density and ultrahigh molecular weight) such as polyethylene (PE) and polypropylene (PP). For example, the filtration medium in the particle removal filter may be composed of at least one polymer selected from the group consisting of nylon, polypropylene (including high density polypropylene), polyethylene, polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkylvinylether copolymer, polyimide, and polyamideimide. A filter composed of the above material can efficiently remove foreign matter (e.g., those having high polarity) that is likely to cause residue defects and / or particle defects, and efficiently reduce the content of metal components in the chemical solution.

[0046] In some embodiments, the filtration medium 114b in the filter 112b may be an ion exchange resin membrane to remove charged particles and / or metal ions from the organic solvent. The ion exchange resin membrane used in the present disclosure is not particularly limited, and a filter containing an ion exchange resin having suitable ion exchange groups immobilized on the resin membrane may be used. Examples of such ion exchange resin membranes include strongly acidic cation exchange resins having cation exchange groups (e.g., sulfonic acid groups) chemically modified onto the resin membrane. Examples of suitable resin membranes include resin membranes including cellulose, diatomaceous earth, nylon (resin having amide groups), polyethylene, polypropylene, polystyrene, resin having imide groups, resin having amide and imide groups, fluororesin, or high density polyethylene membrane. In some embodiments, the ion exchange resin membrane may be a membrane having an integral structure of a particle removal membrane and an ion exchange resin membrane. A polyalkylene (e.g., PE or PP) membrane having ion exchange groups chemically modified thereon is preferred. Cation exchange groups are preferred as the ion exchange groups. The filter having an ion exchange resin membrane used in the present disclosure may be a commercially available filter having metal ion removal functionality. These filters can be selected based on ion exchange efficiency, and the estimated pore size of the filters can be as small as about 0.2 μm (200 nm).

[0047] In some embodiments, the filtration medium 114c in the filter 112c may be an ion-absorbing membrane to remove relatively small particles and / or metal ions from the organic solvent. The ion-absorbing membrane may have a porous membrane material and may have an ion-exchange function. Examples of suitable materials that can be used to prepare the ion-absorbing membrane include, but are not limited to, cellulose, diatomaceous earth, film materials of microfiltration membranes, such as nylon (a resin having an amide group), polyethylene (e.g., high-density polyethylene), polypropylene, polystyrene, resins having an imide group, resins having an amide group and an imide group, fluororesins, membrane materials with ion-exchange functional groups introduced therein, and the like. Examples of the shape of the membrane material include pleated type, flat membrane type, hollow fiber type, porous bodies described in JP-A-2003-112060, and the like. As the ion-exchange group introduced into the membrane material, it is preferable to use a combination of at least two of cation exchange groups, chelate exchange groups, and anion exchange groups in order to optimize the elution and selectivity of the components to be removed. Since the ion adsorption membrane has porosity, it is possible to remove some of the fine particles.

[0048] In some embodiments, the filtration medium 114c may have an average pore size of about 100 nm or less (e.g., about 80 nm or less, about 60 nm or less, about 50 nm or less, about 40 nm or less, about 20 nm or less, or about 15 nm or less) and / or about 5 nm or more (e.g., about 10 nm or more, about 15 nm or more, about 20 nm or more, or about 25 nm or more).

[0049] Without wishing to be bound by theory, it is believed that the ability of the first filtration system 110 to remove impurities can be optimized by using multiple filters having different media types and different pore sizes. For example, in such a first filtration system 110, filter 112a can be a filter having one or more polypropylene media with an average pore size of about 200 nm, filter 112b can be an ion exchange filter, and filter 112c can be a filter having one or more nylon media with an average pore size of about 20 nm.

[0050] In some embodiments, the first filtration system 110 may optionally include a recirculation conduit 160h to form a recirculation loop for recirculating the partially purified organic solvent back to the first filtration system 110 to be processed again by the filters in the first filtration system 110. In some embodiments, a temperature control unit 170 (e.g., a heat exchanger) may be disposed along the recirculation conduit 160h. In such embodiments, the temperature control unit 170 may be configured for a temperature of about 80° F. or less (e.g., about 75° F. or less, about 70° F. or less, or about 65° F. or less) and / or about 30° F. or more (e.g., about 40° F. or more, about 50° F. or more, or about 60° F. or more) such that the temperature of the partially purified organic solvent is maintained at about 80° F. or less as it is recirculated to the first filtration system 110. 1, the recirculation conduit 160h is located upstream of the outflow port 110b of the first filtration system 110. In some embodiments, the recirculation conduit 160h may be located downstream of the outflow port 110b. It is understood that pumps and valves may be provided in the various conduits, outlet and supply ports in the first filtration system 110, the supply unit 20, and the temperature control unit 100, as needed.

[0051] As in the example shown in FIG. 1, purification system 110 may optionally include a temperature control unit 170 (e.g., a heat exchanger) disposed between filters 112a and 112b to adjust the temperature of the organic solvent to about 80° F. or less (e.g., about 75° F. or less, about 70° F. or less, or about 65° F. or less) and / or about 30° F. or more (e.g., about 40° F. or more, about 50° F. or more, or about 60° F. or more) before the organic solvent is introduced into filter 112b and processed.

[0052] It should be noted that the location of the temperature control unit 170 is not limited to the examples given above. In some embodiments, the temperature control unit 170 may be located upstream of the filter 112a, between the filters 112b and 112c, or downstream of the filter 112c. In such embodiments, a separate temperature control unit may or may not be located downstream of the filter 112a before entering the subsequent filters (e.g., the filters 112b and / or 112c). It is optional to locate a separate temperature control unit downstream of the filter 112a, provided that no other means or equipment (e.g., a pump) capable of reintroducing thermal energy to the organic solvent is introduced or located between the filter 112a and the subsequent filters (e.g., the filters 112b and / or 112c).

[0053] In some embodiments, the filter 112 in the first filtration system 110 may not include a filter housing, and the one or more filtration media 114 may have a non-compartmental configuration within the first filtration system 110. For example, the first filtration system 110 may be a multi-stage system including replaceable filtration media 114 (e.g., 114a, 114b, and 114c) concatenated together within the first filtration system 110, and the organic solvent may cascade through the filtration media 114 (e.g., 114a, 114b, and 114c). In such embodiments, the temperature control unit 170 may be located anywhere upstream of the first ion exchange or ion adsorption membrane through which the organic solvent passes or flows. For example, if the first filtration system 110 contains, in sequence downstream of its supply port 110a, a particle removal filter A, a particle removal filter B, an ion exchange membrane A, an ion exchange membrane B, and an ion adsorption membrane A, a temperature control unit 170 may be installed between the particle removal filter B and the ion exchange membrane A to adjust and control the temperature of the organic solvent to about 80° F. or less before the organic solvent passes through the ion exchange membrane A and is processed by the ion exchange membrane A, and is further processed through the subsequent ion exchange membrane B and ion adsorption membrane A. The above examples are for illustrative purposes and are not intended to be limiting.

[0054] 1, the purification system 10 also includes a second filtration system 120 between and in fluid communication with the storage tank 130 and the vessel containment station 140. The second filtration system 120 can include a supply port 120a, one or more (e.g., two, three, four, five, or ten) filters 122, an outflow port 120b, a recirculation conduit 160f, and one or more optional temperature control units 180, all of which are in fluid communication with each other (e.g., through one or more conduits). It is understood that pumps and valves can be provided at the various conduits, outlet and supply ports, and temperature control units within the second filtration system 120, as needed.

[0055] In some embodiments, each filter 122 may include a filter housing and one or more filtration media 124 within the filter housing. For example, the second filtration system 120 shown in FIG. 1 includes two filters (i.e., 122a and 122b), each of which includes one or more filtration media 124a and 124b. In some embodiments, the second filtration system 120 may include only one filter (e.g., 122a). In some embodiments, the filter(s) 122 may not have a separate housing, and the one or more filtration media 124 (e.g., 124a and 124b) have a non-compartmentalized configuration within the second filtration system 120. In another embodiment, the second filtration system 120 may include other purification modules (not shown) in addition to the one or more filters 122.

[0056] 1, filter 122a may include one or more filtration media 124a, and filter 122b may include one or more filtration media 124b, where filtration media 124a and filtration media 124b may differ in functionality or characteristics and may provide different purification processes. In some embodiments, filtration media 124 (e.g., 124a and 124b) contained in corresponding filters 122 (e.g., 122a and 112b) may have the same or similar purification function, physicochemical properties, pore size, and / or materials of construction. In some embodiments, each filter 122 may be independently selected from the group consisting of particle removal filters, ion exchange filters, and ion absorption filters.

[0057] In some embodiments, the filtration medium 124a in the filter 122a may be an ion-absorbing membrane (e.g., as described above for the filtration medium 114c) to remove fine charged particles and / or metal ions in the organic solvent to be purified. In some embodiments, the filtration medium 124a may have an average pore size of about 10 nm or less (e.g., about 7 nm or less, about 5 nm or less, about 3 nm or less, or about 1 nm or less) and / or about 1 nm or more (e.g., about 3 nm or more, or about 5 nm or more). It is believed that the filtration medium 124a can perform both a sieving function (e.g., removing fine particles) and an ion exchange function (e.g., removing charged particles and / or metal ions).

[0058] Examples of suitable materials that may be used in the filtration medium 124a or 124b include polyamides (e.g., nylons such as nylon 6 or nylon 66), polyolefins (e.g., polyethylene or polypropylene), fluoropolymers (e.g., polytetrafluoroethylene (PTFE), perfluoroalkoxyalkanes (PFA), or modified polytetrafluoroethylene (MPTFE)), or copolymers thereof. In some embodiments, the filtration medium 124a or 124b may be composed of a non-fluoropolymer, such as a polyamide (e.g., nylon).

[0059] In some embodiments, the filter 122a may include 1 or more (e.g., 2 or more, 3 or more, 5 or more, 10 or more, 20 or more, 30 or more, 50 or more, or 80 or more) and / or 120 or less (e.g., 110 or less, 100 or less, 90 or less, 70 or less, 50 or less, or 25 or less) filtration media 124a.

[0060] In some embodiments, the filtration medium 124b (e.g., ion-absorbing membrane) in filter 122b may have the same characteristics (e.g., the same pore size) as the filtration medium 124a in filter 122a, except that it is composed of a different material. For example, in some embodiments, if the filtration medium 124a in filter 122a is composed of nylon, the filtration medium 124b in filter 122b may be composed of a fluoropolymer (e.g., PTFE). In some embodiments, filter 122b may include 1 or more (e.g., 2 or more, 3 or more, 5 or more, 10 or more, 15 or more, or 20 or more) and / or 30 or less (e.g., 25 or less, 20 or less, 15 or less, 10 or less, or 5 or less) filtration media 124b.

[0061] Without wishing to be bound by theory, it is believed that the use of a combination of filters 122a and 122b, in which filtration media 124a and 124b are made of different materials, can maximize the reduction of impurities, particles, and metal ions, resulting in ultra-pure organic solvents. Furthermore, without wishing to be bound by theory, it is believed that in an embodiment in which filtration media 124a is made of nylon and filtration media 124b is made of a fluoropolymer (e.g., PTFE), or vice versa, filtration media 124a and 124b can have relatively larger pore sizes (e.g., 5 nm) and still have better filtration results than a filtration media made of another material (e.g., polyolefin) having a smaller pore size (e.g., 3 nm).

[0062] 1, the second filtration system 120 may include a recirculation conduit 160f to form a recirculation loop for recirculating the partially purified organic solvent back to the storage tank 130 to be processed again by the filter 122 in the second filtration system 120. In some embodiments, the partially purified organic solvent is recirculated at least twice (e.g., at least three times, at least four times, or at least five times) before the purification process is completed and the organic solvent is transferred to the container storage station 140. In some embodiments, without wishing to be bound by theory, recirculating the partially purified organic solvent through the second filtration system 120 more than twice may not achieve further improvement in impurity removal. In the example shown in FIG. 1, the recirculation conduit 160f is located downstream of the outlet port 120b of the second filtration system 120. In other examples, the recirculation conduit 160f may be located upstream of the outlet port 120b.

[0063] In some embodiments, the second filtration system 120 may include one or more optional temperature control units 180 (e.g., heat exchangers) at any suitable location. For example, the temperature control unit 180 may be disposed along the recirculation conduit 160f. In some embodiments, the temperature control unit 180 may be disposed between the inlet port 120a and the filter 122a, between the filter 122a and the filter 122b, and between the filter 122b and the outlet port 120b. In some embodiments, the temperature control unit 180 may be configured for a temperature of about 80° F. or less (e.g., about 75° F. or less, about 70° F. or less, or about 65° F. or less) and / or about 30° F. or more (e.g., about 40° F. or more, about 50° F. or more, or about 60° F. or more) such that the temperature of the organic solvent in the second filtration system 120 is maintained at about 80° F. or less.

[0064] In some embodiments, each of filters 122a and 122b includes a filter housing having an inner surface that includes a fluoropolymer (e.g., PTFE, PFA, or a combination thereof). For example, the fluoropolymer may be a coating formed on the inner surface of filters 122a and 122b. In some embodiments, if filter 122a or filter 122b includes a filtration medium that is composed of a fluoropolymer, the entire filter 122a or filter 122b may be composed of a fluoropolymer. In some embodiments, the inner surface of all equipment between filter 122a or 122b and container storage station 140 (including conduits and valves, if present) may include a fluoropolymer. Without wishing to be bound by theory, it is believed that the use of such equipment (also known as fluoropolymer-lined equipment) can significantly reduce the reintroduction of impurities (e.g., metal ions or organic impurities) into the purified organic solvent.

[0065] In some embodiments, when purification system 10 includes both filter 122a and filter 122b in second filtration system 120, at least some (e.g., all) of the components (other than the fluoropolymer filtration media) in the equipment used in purification system 10 (e.g., filters, temperature control units, conduits, valves, inlet ports, or outlet ports) may be constructed from fluorine-free materials. Examples of such materials include stainless steel (including electropolished stainless steel and non-electropolished stainless steel). It is believed that such a system can be relatively inexpensive, reducing production costs, while still being capable of producing ultra-high purity organic solvents.

[0066] In some embodiments, the vessel containment station 140 may be a mobile storage tank (e.g., a tank on a tanker) or a fixed storage tank, hi some embodiments, the vessel containment station 140 may be a fluoropolymer lined facility (e.g., the interior surface of which may include a fluoropolymer such as PTFE).

[0067] The present disclosure also provides a method for purifying a solvent (e.g., an organic solvent). The purification method may generally include passing the solvent through one or more (e.g., two or three) filters (e.g., filter 122a and / or filter 122b) in the second filtration system 120. For example, referring to FIG. 1, the purification system 10 may purify the raw or unprocessed solvent (i.e., starting material) by passing the solvent from the supply unit 20 through filter 112 in the first filtration system 110 to be collected in the storage tank 130 and then passing the solvent from the storage tank 130 through filter 122 in the second filtration system 120 to the container storage station 140. In some embodiments, the purification method described in the present disclosure may include recirculating the solvent at least once (e.g., two or three times) through a recirculation loop in the second filtration system 120 (e.g., through the storage tank 130, the filter 122, and the recirculation conduit 160f) before transferring the purified solvent to the container storage station 140. In some embodiments, the purification methods described herein may include recirculating the partially purified solvent at least once (e.g., two or three times) through a recirculation loop in first filtration system 110 (e.g., through filter 112 and recirculation conduit 160h) before transferring the solvent to storage tank 130.

[0068] In some embodiments, the raw or pre-processed solvent may comprise an organic solvent containing a metal element selected from the group consisting of iron (Fe), chromium (Cr), nickel (Ni), and lead (Pb). In some embodiments, the amount of each metal element in the raw solvent is in the range of 0.1 to 1000 ppt by weight (e.g., 200 to 1000 ppt by weight or 500 to 1000 ppt by weight).

[0069] 1, once the raw solvent reaches a temperature control unit (e.g., unit 100, or any subsequent temperature units such as unit 170 and unit 180), the temperature of the solvent can be adjusted to a predetermined optimal temperature range (e.g., 30° F. to 80° F., 30° F. to 70° F., 41° F. to 67° F., or 50° F. to 65° F.). For example, the solvent temperature may be adjusted to 70° F., 68.5° F., or 67.5° F. In general, the temperature control unit may be capable of maintaining or adjusting the temperature of the solvent at a particular location within the purification system 10 (e.g., before entering a filter) or may be capable of maintaining or adjusting the temperature of the solvent throughout the purification system 10.

[0070] When the number of particles and the amount of impurities detected from the purified solvent at the end of the treatment by the first filtration system 110 and the second filtration system 120 are controlled within a predetermined range, an ultra-high purity solvent (e.g., containing 0.1 to 100 ppt by mass of a metal component selected from the group of metal elements consisting of iron (Fe), chromium (Cr), nickel (Ni), and lead (Pb)) is produced. The ultra-high purity solvent may then be transferred to the container storage station 140 or to a production process for making semiconductor articles.

[0071] In some embodiments, the solvent purified by the methods and systems disclosed herein can have a purity of about 99.5% or greater (e.g., about 99.9% or greater, about 99.95% or greater, about 99.99% or greater, about 99.995% or greater, or about 99.999% or greater). In some embodiments, the solvent purified by the methods and systems disclosed herein has an on-wafer particle count of about 500 or less across an entire wafer (e.g., about 450 or less, about 400 or less, about 350 or less, about 300 or less, about 250 or less, about 200 or less, about 150 or less, or about 100 or less). In some embodiments, solvent purified by the methods and systems described herein has an on-wafer metal count (e.g., total on-wafer metal count or on-wafer metal count of a specific metal, such as Fe or Ni) of about 100 or less (e.g., about 90 or less, about 80 or less, about 70 or less, about 60 or less, about 50 or less, about 40 or less, about 30 or less, about 20 or less, or about 10 or less) across the entire wafer.

[0072] The present disclosure will now be described in more detail with reference to the following examples, which are for illustrative purposes and should not be construed as limiting the scope of the present disclosure. EXAMPLES

[0073] General description of OWPC and OWMC measurements A solvent sample was collected and then inserted into a wafer coating tool. A bare wafer was coated with the sample and the wafer was transferred to and interrogated by a laser-based inspection system. Using laser light, the laser-based inspection system detected, counted, and recorded the location and size of each particle on the wafer with a detection limit of 19 nm. More specifically, the count included particles with sizes of 19 nm and above. This data was used to create a wafer map and provide a total on-wafer particle count (OWPC).

[0074] The wafer was then removed and inspected by EDX (energy dispersive X-ray). Each particle reported by the laser-based inspection system was examined by EDX (energy dispersive X-ray) to provide elemental information. Any particle found to produce any metal signal was counted as a metallic particle. The total number of particles with a metallic signature was tallied and reported as OWMP (on-wafer metallic particles).

[0075] General Description of Total and Trace Metals Measurement The total trace metal concentrations in each solvent sample were tested using inductively coupled plasma mass spectrometry (ICP-MS). Using a method developed by Fujifilm, each sample was tested for the presence of 26 metal species. Detection limits were metal specific, but typical detection limits ranged from 0.00010 to 0.030 ppb. The concentrations of each metal species were then summed to produce a value expressed as total trace metals (ppb).

[0076] Example 1 The solvent purified in this example was cyclohexanone. Referring to FIG. 1, cyclohexanone was purified using the following four purification systems (i.e., systems 1-4), each of which included a first filtration system 110 and a second filtration system 120. In all of systems 1-4, the first filtration system 110 included a 200 nm polypropylene filter as filter 112a, an ion exchange filter as filter 112b, and a 20 nm nylon filter as filter 112c, but did not include a recirculation loop. The differences between systems 1-4 are as follows:

[0077] In system 1, the second filtration system 120 included a 5 nm nylon filter (i.e., a filter made of nylon and having multiple filtration media with an average pore size of 5 nm) as filter 122a and a 3 nm PE filter (i.e., a filter made of polyethylene and having multiple filtration media with an average pore size of 3 nm) as filter 122b in the recirculation loop, but did not include a PTFE-lined fixture or a temperature control unit to control the temperature of the solvent.

[0078] In system 2, the second filtration system 120 included a 5 nm nylon filter as the only filter in the recirculation loop (i.e., filter 122a), included PTFE-lined equipment (i.e., a PTFE-lined filter housing and a PTFE-lined conduit between filter 122a and container storage station 140), and included a temperature control unit 180 along the recirculation conduit 160f for controlling the temperature of the solvent at less than 80 degrees Fahrenheit.

[0079] In system 3, the second filtration system 120 included a 5 nm nylon filter as filter 122a, a 5 nm PTFE filter as filter 122b (i.e., a filter having multiple filtration media composed of PTFE and having an average pore size of 5 nm) in the recirculation loop, PTFE-lined equipment (i.e., PTFE-lined filter housings and a PTFE-lined conduit between filter 122a and container storage station 140), and a temperature control unit 180 along recirculation conduit 160f for controlling the temperature of the solvent to below 80 degrees Fahrenheit.

[0080] In system 4, the second filtration system 120 included a 5 nm nylon filter as filter 122a and a 5 nm PTFE filter as filter 122b in the recirculation loop, contained only stainless steel equipment (i.e., all equipment was constructed from stainless steel), and included a temperature control unit 180 along the recirculation conduit 160f for controlling the temperature of the solvent at less than 80 degrees Fahrenheit.

[0081] The properties of cyclohexanone purified by Systems 1-4 above, including on-wafer particle count, on-wafer total metal count, on-wafer iron count, and total trace metal count, were evaluated and are summarized in Table 1 below.

[0082] [Table 1]

[0083] As shown in Table 1, cyclohexanone purified by System 1 exhibited a relatively high on-wafer particle count, a relatively high on-wafer total metal count, a relatively high on-wafer iron count, and a relatively high total trace metal count. Surprisingly, cyclohexanone purified by Systems 2, 3, or 4 exhibited significantly lower on-wafer particle counts, significantly lower on-wafer total metal counts, significantly lower on-wafer iron counts, and significantly lower total trace metal counts than cyclohexanone purified by System 1.

[0084] Example 2 Ethyl lactate was purified using Systems 5-7. System 5 was similar to System 1 described in Example 1, except that the second filtration system 120 contained only one 5 nm nylon filter. System 6 was similar to System 2 described in Example 1. System 7 was similar to System 3 described in Example 1.

[0085] The characteristics of the ethyl acetate purified by Systems 5-7, including on-wafer particulate count, on-wafer total metal count, on-wafer iron count, on-wafer nickel count, and total trace metal count, were evaluated and are summarized in Table 2 below.

[0086] [Table 2]

[0087] As shown in Table 2, ethyl acetate purified by System 5 exhibited a relatively high on-wafer particle count, a relatively high on-wafer total metal count, a relatively high on-wafer iron count, a relatively high on-wafer nickel count, and a relatively high total trace metal count. Surprisingly, ethyl acetate purified by Systems 6 or 7 exhibited significantly lower on-wafer particle counts, significantly lower on-wafer total metal counts, significantly lower on-wafer iron counts, significantly lower on-wafer nickel counts, and significantly lower total trace metal counts than ethyl acetate purified by System 5.

[0088] Although the invention has been described in detail above with reference to specific embodiments thereof, it will be understood that modifications and variations are within the spirit and scope of what has been described and claimed.

Claims

1. moving the organic solvent through a first filter in a purification system to a container containment station to obtain a purified organic solvent, wherein the first filter comprises a filter housing and at least one filtration medium within the filter housing, the at least one filtration medium having an average pore size of about 5 nm or less; Including, the purification system includes the first filter, the vessel containment station, and a conduit in fluid communication with the first filter and the vessel containment station, the conduit or an interior surface of the filter housing comprising a fluoropolymer; A method for purifying organic solvents.

2. passing the organic solvent through a second filter in fluid communication with the first filter and the container containment station and between the first filter and the container containment station, the second filter comprising a filter housing and at least one filtration medium within the filter housing, the at least one filtration medium within the second filter having an average pore size of about 5 nm or less; The method of claim 1 further comprising:

3. 3. The method of claim 2, wherein the at least one filtration media in the first or second filter comprises a polyamide, a polyolefin, a fluoropolymer, or a copolymer thereof.

4. 3. The method of claim 2, wherein the at least one filtration media in the first or second filter comprises nylon, polyethylene, polytetrafluoroethylene, or copolymers thereof.

5. The method of claim 2 , wherein the at least one filtration media in the first filter comprises nylon.

6. The method of claim 2 , wherein the at least one filtration media in the second filter comprises polytetrafluoroethylene.

7. The method of claim 2 , wherein the inner surface of the filter housing of the second filter comprises a fluoropolymer.

8. 8. The method of claim 7, wherein the fluoropolymer in the first filter, the second filter, or the inner surface of the conduit comprises polytetrafluoroethylene or a copolymer thereof.

9. The method of claim 2 , wherein the second filter is constructed entirely of a fluoropolymer.

10. 3. The method of claim 2, wherein the first filter comprises 1 to 120 filtration media and the second filter comprises 1 to 30 filtration media.

11. 10. The method of claim 1, wherein moving the organic solvent through a first filter to a container containment station is performed at a temperature of about 80 degrees Fahrenheit or less, or the method further comprises passing the organic solvent through a heat exchanger to maintain a temperature of the organic solvent at about 80 degrees Fahrenheit or less.

12. Before passing the organic solvent through the first filter, the organic solvent is passed through a third filter. wherein the third filter comprises at least one filtration medium having an average pore size of about 200 nm or less. The method of claim 1 further comprising:

13. after passing the organic solvent through the third filter and before passing the organic solvent through the first filter, passing the organic solvent through a fourth filter, wherein the fourth filter comprises at least one ion exchange filtration medium; The method of claim 12 further comprising:

14. passing the organic solvent through a fifth filter after passing the organic solvent through the fourth filter and before passing the organic solvent through the first filter, wherein the fifth filter comprises at least one filtration medium having an average pore size of about 20 nm or less; The method of claim 13 further comprising:

15. 10. The method of claim 1, further comprising circulating the organic solvent through a recirculation loop that includes the first filter at least twice prior to transferring the organic solvent to the container containment station.

16. 2. The method of claim 1, wherein the organic solvent comprises cyclohexanone, ethyl lactate, n-butyl acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, 4-methyl-2-pentanol, or propylene carbonate.

17. passing the organic solvent through a first filter and a second filter to obtain a purified organic solvent; the first filter comprises at least one filtration medium having an average pore size of about 5 nm or less and comprising a polyamide, and the second filter comprises at least one filtration medium having an average pore size of about 5 nm or less and comprising a fluoropolymer; A method for purifying organic solvents.

18. 20. The method of claim 17, wherein the polyamide comprises nylon and the fluoropolymer comprises polytetrafluoroethylene.

19. 20. The method of claim 17, wherein the second filter is constructed entirely of a fluoropolymer.

20. 20. The method of claim 17, wherein the first filter comprises 1 to 120 filtration media and the second filter comprises 1 to 30 filtration media.

21. 20. The method of claim 17, wherein passing the organic solvent is conducted at a temperature of about 80 degrees Fahrenheit or less, or the method further comprises passing the organic solvent through a heat exchanger to maintain the organic solvent at a temperature of about 80 degrees Fahrenheit or less.

22. 20. The method of claim 17, wherein the first filter comprises a filter housing and at least one filtration medium within the filter housing, and the second filter comprises a filter housing and at least one filtration medium within the filter housing, and an interior surface of the filter housing of the first or second filter comprises a fluoropolymer.

23. 20. The method of claim 17, wherein the first filter and the second filter are present within a purification system; the purification system further comprises a vessel containment station and a conduit in fluid communication with the first filter, the second filter, and the vessel containment station; and an inner surface of the conduit comprises a fluoropolymer.

24. passing the organic solvent through a third filter prior to passing the organic solvent through the first filter and the second filter, wherein the third filter comprises at least one filtration medium having an average pore size of about 200 nm or less; 20. The method of claim 17, further comprising:

25. after passing the organic solvent through the third filter and before passing the organic solvent through the first filter and the second filter, passing the organic solvent through a fourth filter, wherein the fourth filter comprises at least one ion exchange filtration medium; 25. The method of claim 24, further comprising:

26. passing the organic solvent through a fifth filter after passing the organic solvent through the fourth filter and before passing the organic solvent through the first filter and the second filter, wherein the fifth filter comprises at least one filtration medium having an average pore size of about 20 nm or less; 26. The method of claim 25, further comprising:

27. 20. The method of claim 17, further comprising circulating the organic solvent through a recirculation loop including the first filter and the second filter at least twice prior to transferring the organic solvent to a container containment station.

28. 18. The method of claim 17, wherein the organic solvent comprises cyclohexanone, ethyl lactate, n-butyl acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, 4-methyl-2-pentanol, or propylene carbonate.

29. a first filter, the first filter comprising a filter housing and at least one filtration medium within the filter housing, the at least one filtration medium having an average pore size of about 5 nm or less; a container containment station; and a conduit in fluid communication with the first filter and the container containment station; wherein the filter housing and the inner surface of the conduit comprise a fluoropolymer. system.

30. a first filter, the first filter comprising a filter housing and at least one filtration medium within the filter housing, the at least one filtration medium having an average pore size of about 5 nm or less and comprising polyamide; and a second filter in fluid communication with the first filter, the second filter comprising a filter housing and at least one filtration medium within the filter housing, the at least one filtration medium having an average pore size of about 5 nm or less and comprising a fluoropolymer; A system including:

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