Adsorbent-based storage and delivery vessels with high purity delivery of gases and related methods - Patents.com

Abstract

A storage and dispensing system and associated method are described for storing and selectively dispensing germane (reagent gas) from a container in which the reagent gas is held in adsorptive relationship to a solid sorbent medium within the storage container, the method and dispensing system providing for dispensing of the reagent gas from the storage container with reduced levels of atmospheric impurities contained in the dispensed reagent gas.

Description

[Technical field]

[0001] The present invention relates to a storage and dispensing system, and associated method, for storing and selectively dispensing a high purity reagent gas from a storage vessel in which the reagent gas is held in adsorptive relationship to a solid sorbent medium. [Background technology]

[0002] Gaseous sources (sometimes called "reagent gases") are used in a variety of industries and industrial applications. Some examples of industrial applications include those used in the processing of semiconductor materials or microelectronic devices, such as ion implantation, epitaxial growth, plasma etching, reactive ion etching, metallization, physical vapor deposition, chemical vapor deposition, atomic layer deposition, plasma deposition, photolithography, cleaning, and doping, among others, in the manufacturing processes of semiconductor, microelectronic, photovoltaic, and flat panel display devices and products.

[0003] There remains a need for reliable sources of high purity reagent gases in the manufacture of semiconductor materials and devices and various other industrial processes and applications. Examples of reagent gases include silane, germane (GeH4), ammonia, phosphine (PH3), arsine (AsH3), diborane, stibine, hydrogen sulfide, hydrogen selenide, hydrogen telluride, halide (chlorine, bromine, iodine, fluorine) compounds, among others. Many of these gases must be stored, transported, handled, and used with great care and many safety precautions, including storage vessels that optionally contain the reagent gases at subatmospheric pressure.

[0004] A variety of different types of containers are used to contain, store, transport, and dispense reagent gases for industrial applications. Some containers, referred to herein as "sorbent-based containers," contain gases using a porous sorbent material contained within the container, where the reagent gas is stored by being adsorbed onto the sorbent material. The adsorbed reagent gas may be contained within the container at subatmospheric or superatmospheric pressures and in equilibrium with an added amount of reagent gas that is also present in the container in condensed or gaseous form.

[0005] Gaseous feedstocks must be delivered for use in a concentrated, substantially pure form and must be available in a packaged form that provides a reliable supply of gas for efficient use of the gas in the production system.

[0006] Various process steps and techniques are described to generally reduce the amount of impurities contained within a sorbent-based storage system when preparing the system for use, see International Patent Publication No. WO 2017 / 079550.

[0007] Current commercially available sorbent-based storage systems accommodate many types of high purity reagent gases for selective delivery from a container. These storage systems can deliver reagent gases that contain relatively low levels of impurities, such as atmospheric impurities (nitrogen (N2), carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), and water vapor (H2O)) in amounts less than 10,000 ppmv (ppmv by volume), measured as the total of nitrogen (N2), carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), and water vapor (H2O). For some reagent gases, the total amount of these atmospheric impurities may be as low as 5,000 ppmv, and for other reagent gases, the amount may be as low as 500 ppmv. However, there remains a need for improved sorbent-based storage systems that deliver reagent gases with lower levels of impurities.

[0008] Based on current and previous commercial methods of preparing sorbent-based storage and delivery systems, suppliers of these products have not developed methods and technologies for processing and assembling commercially available storage systems that achieve significantly lower levels of air impurities, including levels of total air impurities well below 500 ppmv (where "total air impurities" is measured as the total (combined) amounts of nitrogen (N2), carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), and water vapor (H2O)). Summary of the Invention

[0009] In one aspect, the present invention relates to a sorbent-based storage system that contains a reagent gas and a sorbent. The system includes a storage vessel that includes an interior, a sorbent therein, and a reagent gas sorbed on the sorbent. The system is capable of dispensing the reagent gas from the vessel, the dispensed reagent gas containing less than 150, 50, 25, or 10 parts per million by volume (ppmv) of total impurities selected from CO, CO2, N2, CH4, and HO, and combinations thereof.

[0010] In another aspect, the invention relates to a process for storing a reagent gas in a vessel containing a sorbent. The process includes providing a sorbent, disposing the sorbent inside the vessel and exposing the sorbent inside the vessel to elevated temperature and reduced pressure to remove residual moisture and volatile impurities. After exposing the sorbent inside the vessel to elevated temperature and reduced pressure, a reagent gas is added inside the vessel. The reagent gas is adsorbed by the sorbent and contained within the vessel at a pressure less than atmospheric pressure. The reagent gas is stored in the vessel and can be selectively dispensed from the vessel, the dispensed reagent gas comprising less than 150 ppm of total impurities selected from CO, CO2, N2, CH4, and H2O, and combinations thereof. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 illustrates a multi-reagent gas system for injecting a number of different reagent gases into a reservoir. [Diagram 2] 1 illustrates an exemplary storage system of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The drawings are schematic, illustrative, non-limiting and not necessarily to scale.

[0013] The present disclosure relates to a storage system for storing a reagent gas in a sorbent material in a sealed container for selectively dispensing the reagent gas from the container. The system is useful as a reversible storage and dispensing system for reagent gas that allows the reagent gas stored in the sorbent in the container to be selectively desorbed (delivered) from the container under fluid dispensing conditions. The system can dispense any of a variety of reagent gases from the container, with the delivered reagent gas containing relatively small amounts of atmospheric impurities, e.g., small amounts of one or more of nitrogen (N2), carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), and water vapor (H2O), and low total amounts (sum) of these impurities measured individually and together.

[0014] This disclosure also describes various steps or techniques that can be used to prepare and assemble the described storage systems, including reagent gas stored in a sorbent contained in a container. Useful steps for preparing and assembling a storage system to accommodate a sorbent and reagent gas stored in a container reduce the amount of impurities present (as compared to a comparable non-inventive storage system) in the container that contains the sorbent and adsorbed reagent gas, and subsequently reduce the amount of impurities present in the reagent gas when it is delivered from the storage container.

[0015] In general, the exemplary method described relates to a process for storing a reagent gas in a vessel containing a sorbent. The exemplary process includes providing a sorbent, disposing the sorbent within the vessel, and exposing the sorbent within the vessel to elevated temperatures and reduced pressures to desorb and remove trace atmospheric impurities that may have been sorbed onto or within the porous sorbent media during handling and packaging.

[0016] Various other optional treatments of the sorbent may be performed in situ (within the vessel) prior to adding the reagent gas to the sorbent inlet vessel to reduce the amount of atmospheric impurities present in the reagent when the reagent gas is vented from the vessel after storage. For example, a useful optional step may be to chemically passivate the porous sorbent of active surface sites that may react with the particular reagent gas being stored. The details of such treatments will depend on the particular sorbent used, as well as the particular type of reagent gas being adsorbed, stored, transported and delivered using the vessel and sorbent. Such treatments may include physical or chemical means to neutralize Lewis acid or base sites.

[0017] More generally, after exposing the sorbent inside the vessel to elevated temperature and reduced pressure, or after any additional or alternative in situ treatment, a reagent gas is added to the vessel interior such that it is adsorbed onto the sorbent and contained within the vessel for storage and selective delivery (exhaust) from the vessel. The reagent gas may be added and contained within the vessel at any pressure, such as superatmospheric or subatmospheric.

[0018] The reagent gas can be stored in a container for a useful period of time and selectively dispensed (evacuated and delivered) from the container for use, the dispensed reagent gas containing less than 150 ppm (by volume) of total impurities selected from, for example, CO, CO2, N2, CH4, and HO, and combinations thereof; for example, the dispensed reagent gas can contain less than 50, 25, 15, or 10 ppmv of total impurities of these impurities.

[0019] Alternatively or additionally, the dispensed reagent gas may contain small amounts of one or more of the individual impurities selected from CO, CO2, N2, CH4, and H2O, and combinations thereof. For example, the dispensed reagent gas may contain less than 25, 20, 15, 10, or 5 ppmv of any of these impurities. Alternatively or additionally, the dispensed reagent gas may contain a combination of two or more different components, each individually measured at less than 25, 20, 15, 10, or 5 ppmv, for example, two or more combinations of CO, CO2, N2, CH4, and H2O, each individually measured at less than 25, 20, 15, 10, or 5 ppmv.

[0020] Traditionally, the purity of reagent gas contained in a sorbent-based storage system has been measured, monitored, and described in terms of the purity of the reagent gas as it is first added to the container for storage, i.e., before the reagent gas is loaded into the storage container for storage in the container. However, depending on the type of storage container, sorbent, and their preparation and assembly, this purity measurement may not be representative of the purity of the reagent gas stored and delivered from the container.

[0021] Zeolites contain metals and oxides that can also interact with a variety of reagent gases and are also known to have a high affinity for atmospheric moisture and contaminants. Metal-organic frameworks (MOFs) by definition incorporate metal ions and clusters, primarily transition metals, that can irreversibly interact with the adsorbed reagent gas species. The synthesis of these specialized adsorbents also uses reactive organic ligands and solvents that can be left at low levels within the pore structure of the crystalline MOF structure, to subsequently react or interact with the adsorbed reagent gas. Thus, defining the purity of the delivered reagent gas by purity analysis of the source gas after adsorption, storage, and transport into the porous storage medium is becoming less and less representative.

[0022] Additionally, users of stored reagent gases continue to require ever-increasing levels of reagent gas purity, including lower levels of atmospheric impurities that may be introduced into the storage vessel as part of a storage vessel component (e.g., a sorbent or vessel), or that may be introduced during assembly, injection, or handling of the vessel or vessel components.

[0023] This specification relates to a method for controlling or reducing the amount of impurities, particularly (but not exclusively) atmospheric impurities, present in a sorbent-based storage system or in systems and devices used to supply reagent gas to a sorbent-based storage system and that may be transferred to the reagent gas stored in and delivered from the sorbent-based storage system. According to this specification, the purity of a reagent gas stored in a sorbent-containing vessel cannot be measured at the time the reagent gas is initially added to the storage vessel for injection (filling) into the storage vessel, but instead can be measured as the reagent gas is delivered (dispensed, exhausted) from the vessel.

[0024] According to this specification, steps and techniques that can be used in the preparation, handling, and assembly of the components of a sorbent-based storage system are performed in a manner that removes atmospheric impurities from the storage system components or reduces or prevents exposure of the storage system components (particularly the sorbent) to atmospheric gases ("atmospheric impurities") such as nitrogen (N2), carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), and water vapor (H2O). A useful method is to reduce the amount of these atmospheric impurities present in the storage vessel (including the sorbent), the system that adds the reagent gas to the storage vessel, or both, to desirably reduce the amount of these atmospheric impurities present in the reagent gas when it is ultimately dispensed from the storage vessel.

[0025] The described storage system includes a container that contains a sorbent material therein. The sorbent material is effective to contain, store, and deliver the reagent gas from the storage container. The reagent gas is adsorbed to the sorbent and exists as a gas inside the container, with a portion of the reagent gas being adsorbed to the sorbent and another portion being in gaseous or condensed gaseous form and in equilibrium with the adsorbed portion. The reagent gas can be initially filled into the container to a desired (e.g., maximum) volume of reagent gas relative to the sorbent based on a desired initial storage pressure in the container, which may be subatmospheric (less than 760 Torr) or superatmospheric pressure (the initial storage pressure is referred to as the "use pressure" or "target pressure" of the injection step after equilibration of the initial amount of reagent gas, see below). The reagent gas is adsorbed to the sorbent for storage and exists in gaseous or condensed form in equilibrium with the adsorbed reagent gas. The gas can then be selectively delivered (dispensed) from the container for use by exposing the sorbent and adsorbed reagent gas inside the container to dispensing conditions.

[0026] As used herein, the term "dispense conditions" means one or more conditions effective to desorb a reagent gas held in a vessel having a sorbent such that the reagent gas disengaged from the sorbent to which it was adsorbed is dispensed from the sorbent and vessel for use. Useful dispense conditions may include conditions of temperature and pressure that cause the reagent gas to be desorbed and released by the sorbent, such as, for example, heating the sorbent (and the vessel housing the sorbent) to effect thermally mediated desorption of the reagent gas, exposing the sorbent to reduced pressure conditions to effect pressure-mediated desorption of the reagent gas, combinations of these, and other effective conditions.

[0027] The pressure inside the vessel (initial "use" pressure) may be subatmospheric, meaning less than about 760 Torr (absolute), or may be superatmospheric. For subatmospheric pressure storage, during storage of the vessel or during use of the vessel to store and dispense reagent gas, the pressure inside the vessel may be less than 760 Torr, e.g., less than 700, 600, 400, 200, 100, 50, 20 Torr, or even lower. For superatmospheric pressure storage, during storage of the vessel or during use of the vessel to store and dispense reagent gas, the pressure inside the vessel may range from about 760 to 50,000 Torr, e.g., from about 1,000 to about 30,000 Torr.

[0028] The described vessels and methods may be useful for storing, handling, and delivering any reagent gas that may be stored as described in equilibrium between an adsorbed portion and a condensed or gaseous portion. The described vessels may be particularly desirable for storing hazardous, toxic, or otherwise dangerous reagent gases. Illustrative examples of reagent gases for which the described vessels and methods are useful include, by way of non-limiting example, silane, methylsilane, trimethylsilane, hydrogen, methane, nitrogen, carbon monoxide, arsine, phosphine, phosgene, chlorine, BCI3, BF3 (including isotopically enriched materials), diborane (B2H6 (including its deuterium analogue)), tungsten hexafluoride, hydrogen fluoride, hydrogen chloride, hydrogen iodide, hydrogen bromide, germane, ammonia, stibine, hydrogen sulfide, hydrogen cyanide, hydrogen selenide, hydrogen telluride, hydrogen deuteride, trimethylstibine, halides (chlorine, bromine, iodine, fluorine), NF3, CIF3, (including isotopically enriched materials), fluorine, iodine, fluor ... These include gaseous compounds such as eF4, SiF4, AsF3, PF3, organic compounds, organometallic compounds, hydrocarbons, organometallic Group V compounds such as (CF3)3Sb, and other halogenated compounds including boron halides (e.g., boron triiodide, boron tribromide, boron trichloride), germanium halides (e.g., germanium tetrabromide, germanium tetrachloride), silicon halides (e.g., silicon tetrabromide, silicon tetrachloride), phosphorus halides (e.g., phosphorus trichloride, phosphorus tribromide, phosphorus triiodide), arsenic halides (e.g., arsenic pentachloride), and nitrogen halides (e.g., nitrogen trichloride, nitrogen tribromide, nitrogen triiodide). Reagent gases contained in a container and adsorbed on a sorbent can also include combinations of two or more gases, for example, a combination of hydrogen gas and a fluorine-containing gas such as boron trifluoride or germanium tetrafluoride. All isotopes of each of these compounds are contemplated.

[0029] The methods and techniques for reducing the levels of impurities in sorbent-based storage systems may be effective in reducing impurities contained in various types of sorbent materials and are not dependent on the particular type or composition of the sorbent. Any of the various types of sorbent materials may be useful with and benefit from the methods described herein to reduce impurities present in sorbent-based storage systems and to reduce the amount of atmospheric impurities present in reagent gases stored using the sorbents.

[0030] Exemplary adsorbents include adsorbent materials selected from carbon-based materials (e.g., activated carbon), silicalite, metal-organic framework (MOF) materials (including zeolitic imidazolate frameworks), polymeric framework (PF) materials, zeolites, porous organic polymers (POPs), covalent organic frameworks (COFs), etc. The adsorbents may be of any size, shape, or form, such as granules, particulates, beads, pellets, or shaped monoliths.

[0031] Specific examples of adsorbent materials are referenced in U.S. Pat. No. 5,704,967, U.S. Pat. No. 6,132,492, and PCT International Patent Publication Nos. 2017 / 008039 and 2017 / 079550, each of which is incorporated by reference herein in its entirety.

[0032] Metal-organic frameworks generally include highly porous materials made from organic linkers coordinated to metal ions or metal oxide clusters in a crystal structure. Various classes of MOFs are known, including ZIF-like MOFs (zeolitic imidazole frameworks), MILs (Materials Institute Lavoisier), MOF materials (e.g., MIL-100), IRMOF-like materials (e.g., IRMOF-1), M-MOF-74 / CPO-27-M-like paddlewheel MOFs (where M can be Zn, Fe, Co, Mg, Ni, Mn, or Cu), Zn-oxide node frameworks, and DMOF-like MOF materials (e.g., DMOF-1).

[0033] One class of MOFs useful or preferred as adsorbents is that of zeolitic imidazolate frameworks or "ZIFs". Zeolitic imidazolate frameworks are a type of MOF that contain tetrahedrally coordinated transition metals, such as iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), magnesium (Mg), manganese (Mn) or zinc (Zn), connected by imidazolate linkers, which may be the same or different within a particular ZIF composition or for single transition metal atoms of the ZIF structure. ZIF structures contain tetrahedrally coordinated transition metals linked via imidazolate units to produce extended structures based on tetrahedral topology. ZIFs are said to form structural topologies equivalent to those found in zeolites and other inorganic microporous oxide materials.

[0034] A variety of carbon materials are useful as adsorbents, including carbons formed by pyrolysis of synthetic hydrocarbon resins such as polyacrylonitrile, sulfonated polystyrene-divinylbenzene, and polyvinylidene chloride, activated carbons formed from natural source materials such as cellulose char, charcoal, coconut shells, pitch, wood, petroleum, and coal, nanoporous carbons, and the like.

[0035] One particular example of a carbon adsorbent (nanoporous carbon) has pore (slit) sizes between 0.5 and about 1 nm, a large micropore volume (>40%, with macropores (>5 nm) and void volume only about 10%) and a large surface area (e.g., about 1,100 m). 2 A typical example of nanoporous carbon material is a carbon pyrolysate of polyvinylidene chloride (PVCD) polymers or copolymers that can be formed into pyrolysates that can have high densities (e.g., on the order of about 1.1 g / cc) with a density of 1.0 g / cc (1.0 g / g). Microscopically, such nanoporous carbon materials consist of graphene sheets (sp2 hybridized graphitic planes) that are folded and interleaved in a somewhat random orientation, resulting in relatively high electrical and thermal conductivity. See International Patent Publication No. WO 2017 / 079550, which is incorporated herein by reference in its entirety.

[0036] Useful or preferred carbon sorbents may be of a type and character that is substantially pure prior to being placed in a vessel as a sorbent in a system as described. The purity of an effective carbon sorbent material may be characterized in terms of the ash content of the carbon. For example, useful or preferred carbon sorbents may contain 0.01% by weight or less ash as measured by standard tests, e.g., ASTM D2866-83 or ASTM D2866.99. Carbon purity may preferably be at least 99.99% as measured by particle induced x-ray emission techniques (PIXE).

[0037] In accordance with the present disclosure, one or more of various steps may be performed on the sorbent, on the container to house the sorbent as part of the storage system, or during assembly of the storage system (including injecting the reagent gas into the container) to reduce the amount of atmospheric impurities present in the container, sorbent, and reagent gas during storage and delivery of the reagent gas. After a typical storage period of the reagent gas in the container, the amount of atmospheric impurities in the reagent gas is reduced as the reagent gas is stored in and delivered from the container. A typical storage period (at ambient temperature, 25° C.) of the described system including the container containing the sorbent and reagent gas may be for a period of several weeks (e.g., 1, 2, 6, or 8 weeks) or several months (e.g., 3, 6, 9, or 12 months), during and after which a useful or preferred system can deliver a reagent gas containing the described relatively low levels of atmospheric impurities, e.g., as compared to alternative storage systems.

[0038] As one technique for reducing impurities in a storage system, particularly impurities present in the sorbent, the sorbent may be treated by a pyrolysis step that reduces the amount of impurities present in the sorbent. The pyrolysis step may be performed before the sorbent is added to the vessel and may be performed on any sorbent that is thermally stable enough to withstand the heating conditions of the pyrolysis step. Examples of sorbents that can withstand pyrolysis include carbon-based sorbents.

[0039] The pyrolysis step generally refers to pyrolysis in an oxygen-free environment. Pyrolysis may be performed by exposing the sorbent to any suitable pyrolysis conditions, and may be performed in a gradual manner, including increasing the temperature from an ambient starting temperature to a desired high-temperature pyrolysis temperature, for example, in the temperature range of 600°C to 1000°C, if desired or useful. The time of the pyrolysis process step may be any effective time, for example, a total time ranging from 1 to 7 days, or longer, as desired. The atmosphere in which the pyrolysis step may be performed may be an inert atmosphere free of oxygen, carbon monoxide, carbon dioxide, and moisture. Exemplary atmospheres include nitrogen, argon, and forming gas (a mixture of 5% hydrogen in nitrogen). See International Patent Publication No. 2017 / 079550, U.S. Patent Application Publication No. 2020 / 0206717, which are incorporated herein by reference in their entireties.

[0040] Following the pyrolysis step, the sorbent treated by pyrolysis may contain levels of atmospheric impurities of less than about 50, 40, or 20 ppmv for each of nitrogen (N2), carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), and water vapor (H2O), measured individually. The sorbent may contain less than 70, 60, or 50 ppm of the total amount of nitrogen (N2), carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), and water vapor (H2O), combined (in total) for all of these impurities.

[0041] Useful methods of preparing storage systems as described having reduced levels of atmospheric impurities following pyrolysis of a sorbent that can withstand pyrolysis temperatures, or following another step of preparing other types of sorbents, can include steps and techniques for handling the sorbent in a manner that prevents exposure of the sorbent to atmospheric gases before and when it is placed in the storage vessel (e.g., following pyrolysis).

[0042] As an example, the sorbent subject to pyrolysis (e.g., pyrolyzed carbon-type sorbent) may be placed in a storage container immediately after the pyrolysis step to reduce or prevent exposure of the sorbent to atmospheric impurities after the pyrolysis step and before placing the pyrolyzed sorbent in a storage container. For example, the pyrolyzed sorbent may be directly packaged or loaded into a container (a storage system container) (or alternatively a prepackage such as a gas-impermeable bag) without exposure to the ambient environment via direct injection in a dry, inert (e.g., nitrogen atmosphere) purged containment system. The sorbent material may be transferred directly from the pyrolysis furnace through an insulating gate into a package (e.g., a container, cylinder, or gas-impermeable bag in a controlled environment). The medium may be in a controlled atmosphere (e.g., dry nitrogen, optionally cooling the ambient environment to reduce atmospheric moisture content), not exposed to the ambient atmosphere (i.e., air), and loaded into the package within a short period of time after the pyrolysis step, such as within 30 minutes after the end of the pyrolysis step. Because the adsorption capacity of the adsorbent is reduced at elevated temperatures, the adsorbent media may be transferred from the pyrolysis step to the package for a short period of time (e.g., less than 30, 20, or 10 minutes) at elevated temperatures between 40° C. and 65° C., optionally in a dry, low-oxygen (e.g., containing less than 1, 0.5, or 0.1% oxygen by volume) environment (e.g., enriched nitrogen). In various exemplary methods using the same atmosphere and timing, the media may be loaded directly into a different package, such as a storage vessel (e.g., a cylinder) or a gas-impermeable package (e.g., a "gas-impermeable bag") (see International Patent Publication No. WO 2017 / 079550). If a temporary gas-impermeable package is used, the package may also include optional desiccant materials, oxygen scavengers, or both, to further protect the media until it is transferred to the storage vessel.

[0043] According to such steps, the pyrolyzable sorbent may be subjected to a pyrolysis step in a pyrolysis furnace to form a pyrolyzed sorbent. The pyrolyzed sorbent may be discharged from the pyrolysis furnace at a discharge location, or the pyrolyzed sorbent may be placed directly in a storage vessel at the discharge location, for example, delivered inside a gas storage dispensing vessel. See International Patent Publication No. 2017 / 079550, US Patent Publication No. 2020 / 0206717. These steps may be performed in a manufacturing facility that includes an enclosure that houses the pyrolysis furnace. The enclosure may further house (enclose) a sorbent injection station at the discharge location of the pyrolysis furnace, the sorbent injection station configured to place the pyrolysate sorbent in a package (e.g., a gas storage vessel, a gas-impermeable bag, or another package). The enclosure may be supplied with an inert (optionally and preferably low-oxygen) gas environment, such as nitrogen, or one or more additive gases that facilitate the manufacturing process. The enclosure may also include an active getter to control moisture, oxygen, or another atmospheric impurity. The carbon pyrolysate sorbent may be placed in the package under a concentrated inert atmosphere (e.g., containing at least 99 or 99.9% (by volume) of one or more of nitrogen, helium, argon, xenon and krypton), or under a reducing atmosphere of hydrogen, hydrogen sulfide, or other suitable gas, or a combination of an inert gas and a reducing gas.

[0044] According to another technique for reducing the presence of atmospheric impurities in the storage system, particularly in the material of the container, the container, particularly the container interior, may be prepared from a material that reduces the presence of atmospheric impurities inside the container during use of the container. The container or other components of the storage system (e.g., valves) may be made of materials such as metals, metal alloys, coated metals, plastics, polymers, or combinations thereof that can be selected or treated to reduce the introduction of impurities into the storage container interior. Polished smooth and low surface roughness surfaces, such as container walls, may be less reactive with the reagent gas contained inside the container and less likely to adsorb gas or moisture from its surroundings, and therefore may be preferred as the interior surface of the storage container as described. See, e.g., paragraphs

[0029] and

[0030] of International Patent Publication No. 2017 / 079550. Specific examples of useful or preferred materials for the storage container interior may be selected based on the type of adsorbent or reagent gas contained in the container. High nickel metal alloys or highly polished (low surface roughness) or coated metals or high performance plastics can be helpful to minimize interactions and impurities, especially with halide gases as stored reagent gases.

[0045] Alternatively or additionally, to further reduce the presence of atmospheric impurities in the storage system, particularly those contained in the material of the container, the container (of any material) may be exposed to heating and an optional vacuum step prior to adding the sorbent to reduce the amount of impurities adsorbed in trace amounts that may be contained within the material of the container, e.g., in the sidewalls and bottom of the container, or in other components of the storage system such as the container or valves. The container or other components of the system may be made of materials such as metals, metal alloys, coated metals, polished metals, plastics, polymers, or combinations thereof. Any of these materials may contain very small or trace amounts of adsorbed impurities such as moisture, another atmospheric impurity, or organic volatile materials.

[0046] The steps of cleaning, drying, passivating, purging, or heating the container before a sorbent is added and contained within the container may be performed while the container does not contain a sorbent by exposing the container or other components of the storage system to any suitable conditions that release (degas) or otherwise remove impurities that may be contained in the material, e.g., by high temperature, reduced pressure, chemical or physical mechanisms, etc. One or more of these steps may be performed prior to adding any sorbent within the container.

[0047] The step of heating the vessel, optionally at reduced pressure, to remove adsorbed impurities from the vessel or system materials may be carried out in any effective manner at useful temperatures and pressures, including temperatures at which the vessel or system materials are thermally stable. Certain materials used in the vessel or storage system are less stable than others, and the temperature used during the heating step is one at which the particular material remains stable and does not decompose. The heating step may be carried out in a gradual manner, including increasing the temperature from an ambient starting temperature to a desired elevated temperature, higher than temperatures the vessel will encounter during storage, transport, and use, at temperatures ranging from, for example, 110°C to 300°C, and the heating step may be carried out for a range of times, as desired and effective, from 8 hours to 40 hours. A preferred heating step may also be carried out in a vacuum atmosphere, such as at pressures below 650 Torr, for example, below 3 Torr, or at pressures below 1×10 -4 Less than Torr or 1×10 -5 It may be carried out at pressures below Torr.

[0048] As another particular technique for reducing the presence of atmospheric impurities in a storage system, particularly as contained in a sorbent, the sorbent may be subjected to a heating and depressurization step after placement in a storage vessel to reduce the amount of impurities present in the sorbent. The heating step may be performed on the sorbent contained in the vessel by exposing the sorbent and the vessel containing the sorbent to any suitable heating and pressure conditions capable of removing the amount of atmospheric impurities that may be contained in the sorbent after placement in the vessel, without causing undue detrimental thermal effects to the sorbent. The heating step is performed prior to the addition of reagent gas to the sorbent and inside the vessel.

[0049] The step of heating the sorbent in the vessel to remove atmospheric impurities may be carried out in any effective manner at useful temperatures and pressures, including temperatures at which the sorbent is thermally stable. Certain sorbent materials are less stable than others, and the temperature used during the heating step is one at which the particular sorbent remains stable and does not decompose. The heating step may be carried out in a gradual manner, including increasing the temperature from an ambient starting temperature to a desired elevated temperature, for example in the temperature range of 110°C to 300°C, and the heating step may be carried out for a variety of periods ranging from 8 hours to 40 hours, or longer, as desired and effective. A preferred heating step is at a pressure of less than 5 Torr, for example 1×10 -5 or 1×10 -6 It may be performed in a vacuum atmosphere, such as a pressure below Torr.

[0050] The described methods may also include a step of chemically passivating the adsorbent before or after it is placed in the container. The chemical passivation step may include exposing the surface sites of the adsorbent to a chemical in the form of a gas (a passivation gas) to remove residual adsorbed impurities (e.g., atmospheric impurities) or to neutralize or inactivate the active surface sites of the adsorbent. The amount and type of passivation gas in the passivation step, as well as the exposure time of the passivation gas to the adsorbent, may depend on the type of adsorbent and the type of reagent gas stored by adsorption on the adsorbent.

[0051] As a single example, the step of chemically passivating the adsorbent may be performed in a vessel housing the adsorbent by exposing the adsorbent to a reagent gas that is the same reagent gas that will be charged to the vessel in a subsequent charging step. That is, the reagent gas stored in the vessel is used as the passivating gas in the step of passivating the adsorbent. The adsorbent may be exposed to the reagent gas at any pressure and for any time that will chemically passivate the adsorbent by reacting with and passivating active surface sites on the adsorbent prior to charging the vessel with the same reagent gas for the purpose of storing the reagent gas in the vessel. Optionally, the adsorbent may be exposed to a high pressure but low concentration of the reagent gas as the passivating gas in an inert, non-reactive gas, such as diluted to a concentration of 2, 5, or 10% (by volume) and pressurized to 1,000, 2,000, or 5,000 Torr.

[0052] For example, in the chemical passivation step, the adsorbent may be exposed to the reagent gas at a relatively low pressure, e.g., less than 760 Torr, e.g., pressures ranging from 1, 2, 5, or 10 Torr, up to 50, 100, 200, or 500 Torr, etc. The time for exposing the adsorbent to the passivation gas may be any useful time, e.g., a time ranging from 15 to 2500 minutes, e.g., 60 to 1000 minutes. The passivation step may be carried out at ambient temperature or at an elevated temperature, e.g., a temperature ranging from 60° C. to 300° C., e.g., 85° C. to 250° C. After exposing the adsorbent to the passivation gas for the desired time, the passivation gas is then passed through a vacuum, e.g., pressures less than 3 Torr, e.g., pressures ranging from 1×10 -5 or 1×10 -6 It is removed from the adsorbent by exposure to a pressure of less than 1 Torr.

[0053] According to another optional step of treating the adsorbent to reduce the amount of atmospheric impurities present in the adsorbent, the adsorbent may be contacted with a "displacement gas", optionally at elevated pressure and temperature, optionally through multiple cycles of exposure, to remove the impurities from the adsorbent into the displacement gas. This step contacts the adsorbent with the displacement gas in a manner effective to displace the impurities from the adsorbent, and the displacement gas is then removed from the adsorbent to obtain an adsorbent with reduced amounts of atmospheric impurities. The pressure and temperature may be controlled and may be increased and optionally regulated, i.e., cycled between higher and lower pressures or higher and lower temperatures.

[0054] The replacement gas may be an inert gas, such as one or a combination of nitrogen, helium, argon, xenon, or krypton. Alternatively, the replacement gas may be a reducing gas, such as hydrogen or hydrogen sulfide, or a combination of an inert gas and a reducing gas, for example, a mixture of about 5% (by volume) hydrogen in the remaining nitrogen.

[0055] After the desired steps of preparing the sorbent and disposing it inside the storage vessel, the vessel can be primed with a reagent gas ("loaded" or "filled") to a desired pressure and the reagent gas can be introduced inside the vessel to adsorb onto the sorbent, while the sorbent is treated as described to reduce or minimize the amount of atmospheric impurities to which it is exposed or contains.

[0056] In order to reduce or control the amount of atmospheric impurities that become present in the vessel, i.e., that may be added to the vessel or reagent gas during the step of filling the vessel with the reagent gas, various steps may be performed on the vessel and sorbent during the filling step, and specific injection devices may be used during the injection step. These generally include any one or more of the following: use of the highest purity reagent gas possible, or purification of the reagent gas prior to introduction into the storage vessel; use of injection devices that are processed, handled, and used in a manner that reduces exposure of the apparatus (particularly the interior space) to the atmospheric gas or gases; and steps of the injection process that may be effective to remove atmospheric impurities from the injection device and vessel during or after addition of the reagent gas to the vessel, any of which may be useful alone or in combination of two or more of these.

[0057] 1 shows a non-limiting example of a system 100 including individual injection stations 110a, 110b, 110c, and 110d, each having its own reagent gas source (112a, 112b, 112c, 112d) and conduits (114a, 114b, 114c, 114d) (including multiple valves as shown). In use, each reagent gas source contains a different reagent gas (122, 124, 126, 128), and each individual conduit 114 (a, b, c, or d) is used to flow only a single type of reagent gas for injection into a receiving vessel (116a, 116b, 116c, or 116d).

[0058] Each injection station also includes a temperature monitoring and control system (e.g., jacket) 132a, 132b, 132c, and 132d effective to accurately monitor and control the temperature of the receiving vessel and its contents during the injection step. Each injection station also includes a pressure monitoring and control system effective to accurately monitor and control the internal pressure of the receiving vessel during the injection step. An exemplary injection station can include a temperature control system that can monitor and control the temperature of the receiving vessel, the reagent gas entering the receiving vessel during the injection step, or the contents of the receiving vessel during the injection step (reagent gas, sorbent, or both) to a desired set point temperature, to a temperature within a range of not more than 3° C. above or below the set point temperature, for example, not more than 1° C. or not more than 0.5° C. above or below the set point temperature.

[0059] Each station may be dedicated for at least a useful or large number of injection cycles (one cycle injects one container 116), e.g., at least 100, 500 or 1000 injection steps (a single injection step injects reagent gas into one storage container), and injects only one particular type of reagent gas into the receiving container. Use of an injection station with a single reagent source, i.e., use of the injection station to inject only one type of reagent gas into the storage container, rather than long-term use of the injection station, may be effective to avoid excessive exposure of the station and associated conduits to environmental impurities during switchover from one reagent gas to a different reagent gas. Dedicated injection stations also reduce the possibility of cross-contamination of different types of reagent gas between the storage containers injected by the station.

[0060] Similarly, to prevent the possibility of cross-contamination between receiving vessels, each injection station may optionally include (as shown) only a single reagent gas source 112 (a, b, c, or d) and only a single outlet 134 (a, b, c, or d) to which a receiving vessel (116a, b, c, or d) can be connected for flowing reagent gas (122, 124, 126, or 128) from the gas source to the receiving vessel using the injection station.

[0061] Optionally, for each or all of the injection stations 110a, 110b, 110c, and 110d independently, the inner surface of the conduit 114a, 114b, 114c, or 114d, or any surface that contacts the reagent gas during the injection step, can be made of a material such as a metal, a metal alloy, a coated metal, a plastic, a polymer, or a combination thereof, and can be selected or treated to avoid the introduction of impurities from the surface to the reagent gas during the flow of the reagent gas through the surface. A polished, smooth, low surface roughness surface of the conduit is less reactive with the reagent gas flowing through the conduit and less adsorbs gas or moisture from the surroundings, and may be preferred as an inner surface. See, e.g., paragraphs

[0029] and

[0030] of International Patent Publication No. 2017 / 079550. Specific examples of useful or preferred materials for the interior of the conduit may be selected based on the type of adsorbent or reagent gas contained in the vessel. High nickel metal alloys or highly polished (low surface roughness) or coated metals or high performance plastics can help minimize interactions with halide gases and impurities.

[0062] To further remove environmental impurities, purge valves (130a, 130b, 130c, 130d) are present in the conduits of each injection station. The purge valves may be useful to purge the conduits during an injection cycle, before an injection cycle, or after a period of non-use (e.g., at least 2, 4, 6, or 8 hours) during which a certain amount of reagent gas has not flowed through the conduit, e.g., the conduit has been held in place without flowing through the conduit.

[0063] The purge valve may optionally be directly connected to a scrubber or other type of reagent gas waste container and may be opened immediately prior to the injection step to purge (send to the scrubber or waste container) the amount of reagent gas present in the conduit, so that the reagent gas to be added to the receiving container (116a, b, c, or d) is the reagent gas stored in the reagent gas source (112a, 112b, 112c, or 112d) that has not been present (or stationary) in the conduit (114a, 114b, 114c, or 114d) for a period of time. The amount of reagent gas released from the conduit during this purge step may be at least a volume of reagent gas approximately equal to the volume of the conduit extending between the reagent gas source (112a, 112b, 112c, or 112d) and the purge valve (130a, 130b, 130c, or 130d).

[0064] Alternatively or additionally, to further remove environmental impurities, the reagent gas may flow through the injection station's conduits at a relatively low gas pressure, velocity, or both.

[0065] Low reagent gas pressure in the conduits and flow paths of the injection system can be effective to minimize or slow reactions between the reagent gas flowing through the conduit or system and any reaction sites available on the interior surface of the conduit or system. Exemplary pressures of reagent gas in the conduits can be less than 50 pounds per square inch (gauge) (psig), such as less than 25 or 15 psig.

[0066] Additionally or alternatively, to reduce the presence of environmental impurities that become present in the reagent gas stored in and delivered from the container, the injection step may be performed using a relatively slow rate of reagent gas entering the container through the injection system (e.g., its conduit), and a relatively slow increase in gas pressure in the receiving container can be achieved while the container is being injected with reagent gas.

[0067] An example of a useful velocity of the reagent gas through the injection system, e.g., its conduits, and into the receiving vessel can be a velocity of less than 1000 standard cubic centimeters per minute (sccm), e.g., less than 500 sccm or less than 250 sccm, which may be the flow of the reagent gas at the outlet of the injection system as it leaves the injection station and enters the reservoir.

[0068] Examples of useful pressure rise rates for reagent gas flowing into the storage vessel can be pressure rises within the vessel of less than 100 Torr / hour, such as less than 1 Torr / minute, or less than 0.5 Torr / minute.

[0069] A slow injection rate or a slow pressure rise rate can theoretically reduce impurities generated during the injection step that may be introduced into the reagent gas during the injection step, because it is believed that a slow and controlled injection rate prevents spikes in pressure and temperature of the system or individual components of the system (vessel, reagent gas, and sorbent media) due to adsorption heat that may increase reaction rates or reactivity. More specifically, directly injecting the storage vessel with a given maximum injection volume of reagent gas will cause significant adsorption heating of the sorbent and reagent gas, resulting in a fairly rapid increase in the vessel's internal pressure that is much higher than the target, which eventually drops as the sorbent cools and the adsorption capacity returns. By using a low injection rate and a slow rate of injection of the storage vessel, rapid increases (spikes) in temperature, pressure, or both in the storage vessel can be avoided or minimized. By avoiding excessive increases in temperature, pressure, or both of the sorbent and reagent gas in the vessel, the extent of reaction between the reagent gas, vessel, and media (sorbent) while the reagent gas is being added inside the storage vessel can be controlled or reduced.

[0070] The injection step of flowing reagent gas into a receiving vessel using a system such as system 100 of Figure 1 or using an individual injection station (e.g., 110a) shown in Figure 1 may be performed in a cycle that includes adding reagent gas to the vessel (up to a desired internal pressure), allowing the vessel to come to equilibrium (by the reagent gas adsorbing onto or desorbing from a sorbent) at the desired pressure after the flow of reagent gas into the vessel is stopped, and after achieving equilibrium, reducing the pressure inside the vessel by removing (purging) an amount of reagent gas from inside the vessel, for example from the headspace inside the vessel. After purging, the vessel is allowed to come to a second (adjusted) equilibrium with a reduced amount and pressure of reagent gas inside.

[0071] 1, a conduit (e.g., 114a) of an injection station (e.g., 110a) may be first purged by releasing reagent gas through valve 130a in an amount (by volume) equal to or greater than the volume of the space defined within conduit 114a, with the conduit initially containing reagent gas from a reagent gas source and with the valve (140a, 140b, 140c, or 140d) to the reagent gas source open. Reagent gas (e.g., 122) then flows slowly at low pressure from the reagent gas source (e.g., 112a) through the conduit (e.g., 114a) into a receiving vessel (e.g., 116a) that contains a sorbent and is precisely maintained at a desired set point temperature, e.g., within 1° C. above or below the set point temperature. An injection rate (velocity of reagent gas into the receiving vessel) with a slow rate of pressure rise inside the vessel may result in less atmospheric impurities being released into the receiving vessel, as the level of reactivity between the reagent gas, vessel, and sorbent medium may be reduced by avoiding a rapid increase in temperature and pressure inside the vessel (i.e., a temperature or pressure "spike") during the injection step.

[0072] In an exemplary method, reagent gas is added to a receiving vessel in an amount that exceeds the use pressure of the storage vessel (also known as the "target pressure" or "final fill pressure"), i.e., the initial pressure of the vessel when the vessel contains an amount of reagent gas for use of the vessel and stores, transports, and selectively releases the reagent gas from the vessel for use. The internal pressure of the vessel, which may be greater than the use pressure at this initial stage of the fill process, may be the maximum pressure that the vessel will encounter during storage, transport, and use of the vessel when filled with reagent gas, or a pressure lower than that pressure and higher than the use pressure that is expected to be present. For a vessel designed to contain a reagent gas at sub-atmospheric pressure, examples of internal pressures of a vessel with excess amounts of reagent gas added as described may be pressures of at least 760, 1000, or 1200 Torr. For example, at a target pressure (final fill pressure) of 650 Torr, the vessel may be initially filled at a range of 700 Torr to 1000 Torr, e.g., greater than 760 Torr, or greater than 800 Torr, and allowed to equilibrate before pumping back to the target 650 Torr.

[0073] Measured another way, as described, an example internal pressure of a vessel (designed for subatmospheric storage of reagent gas) to which an excess amount of reagent gas has been added can be at least 10, 20, or 50% greater than the target pressure ("operating pressure"). For example, if the vessel contains reagent gas at a pressure of 760 Torr during use ("operating pressure" means the pressure of the vessel when it is filled with reagent gas for storage, transport, and selective delivery of reagent gas), the vessel can be primed with excess reagent gas in this step to achieve an internal pressure that is 10, 20, or 50% greater than the "operating pressure" of 760 Torr, i.e., 836 Torr, 912 Torr, or 1,140 Torr, respectively.

[0074] After the excess amount of reagent gas is added, the container is equilibrated, meaning that the amount of reagent gas adsorbed on the sorbent and the amount of gaseous reagent gas present as a gas in the headspace volume of the container are in thermodynamic equilibrium. After the excess amount of reagent gas is added, the container is held (e.g., at a constant temperature) for a sufficient time to achieve equilibrium, and the gaseous reagent gas contained as a gas in the headspace potentially contains a certain amount of atmospheric impurities that have migrated from the sorbent to the gaseous reagent gas in the headspace. The reagent gas in the headspace, along with any impurities contained therein, can then be released from the container to remove the impurities and bring the container to a lower reagent gas content and a lower pressure, e.g., the reagent gas content and initial pressure as intended for the purpose of transporting and storing the reagent gas in the container, e.g., the "target pressure" or "working pressure".

[0075] The time required to reach the described equilibrium after adding an excess amount of reagent gas may vary depending on factors such as the type of sorbent, the type of reagent gas, the amount of sorbent relative to the total volume of the vessel and the volume of the headspace in the vessel, the amount of reagent gas added to the vessel, the pressure inside the vessel, etc. Exemplary times after adding reagent gas to the described excess pressure and releasing an amount of reagent gas along with impurities may range from 30 minutes to 1000 hours, such as 1 hour to 500 hours, such as 2 hours to 100 hours, etc.

[0076] Still other alternative or additional means may be useful to control the amount of atmospheric contaminants that may be introduced into the reagent gas during injection by controlling the exposure of the gas handling and injection equipment (e.g., gas handling injection manifold) to atmospheric gases, such as the ambient atmosphere (the "room air" present in the system's immediate environment). These means may include check valves located at the outlets (e.g., outlets 134a, b, c, or d) of the system of FIG. 1. The check valves may effectively prevent reverse flow (or "backflow") of the ambient atmosphere (room air) into the lines of the injection system when a reservoir is removed or replaced (engaged or disengaged from the system) at the outlet.

[0077] Alternatively or additionally, maintaining a low level flow ("trickle purge") of inert gas through conduits or other components of the injection system can be maintained whenever a seal is broken within the gas handling system, e.g., whenever an interior space (e.g., conduits) of the system is fluidly exposed to ambient or "room air". In this way, the inert gas continuously sweeps through the conduits and other flow control structures of the system, minimizing diffusion of atmosphere (room air) back into the conduits at any openings. For example, a flow of ultra-high purity nitrogen of 50 sccm or more, or a flow of pure helium of 25 sccm can be used to minimize air ingress into the interior locations of the system.

[0078] Optionally or additionally, the reagent gas handled by the gas injection system and delivery manifold (outlet) can pass through an in-line gas purifier just prior to entering the adsorbent-injected receiving storage vessel. In this manner, contaminants (atmospheric impurities) that may have been introduced into the system (e.g., conduits, controls, etc.) can be removed down to ppb (parts per billion) levels before the reagent gas enters the vessel. Such point-of-use purifiers can be designed for the particular reagent gas being handled by one of skill in the art. Such purifiers can be infused with highly selective adsorbents or molecular sieve materials to selectively remove contaminants, e.g., atmospheric impurities, at the point of injection.

[0079] When the reagent gas is added to the container or when it is introduced into the injection station, the reagent gas may be in a high purity state, including possibly containing very small amounts of atmospheric gases as impurities.

[0080] An example of a hydride reagent gas, when initially loaded into a storage vessel (containing a sorbent) or included as a feedstock for an injection station (e.g., as contained in reagent gas source 112a of FIG. 1), may contain atmospheric impurities at levels less than about 2 ppmv for each of nitrogen (N2), carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), and water vapor (H2O), measured individually. The reagent gas may contain less than 5 ppmv total of nitrogen (N2), carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), and water vapor (H2O). A preferred hydride gas source may contain a maximum amount of each of the individual listed impurities that is lower than each of these individual atmospheric impurities, e.g., less than 1 ppmv, or less than 0.5 ppmv or 0.2 ppmv. Preferred hydride gas sources may contain a total amount (combined) of these impurities that is less than 1 ppmv, or less than 0.5 ppmv or 0.2 ppmv.

[0081] The useful, acceptable, or preferred amounts of these impurities may vary for fluoride gas as a reagent gas, either individually or collectively. For fluoride reagent gas, when loaded into a sorbent contained in a storage vessel or as a reagent source for an injection station (e.g., 112 in FIG. 1), the maximum amount of each of the individual atmospheric impurities may preferably be less than about 10 ppmv for each of nitrogen (N2), carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), and water vapor (H2O), measured individually. The reagent gas may contain less than 50 ppmv total of nitrogen (N2), carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), and water vapor (H2O). A preferred fluoride gas source may contain a maximum amount of each of the listed individual impurities that is lower than each of these individual atmospheric impurities, e.g., less than 2 ppmv, e.g., less than 1 ppmv. Preferred fluoride gas sources may contain a total amount (combined) of these atmospheric impurities of less than 4 ppmv, or less than 3 ppmv or 2.5 ppmv.

[0082] The amount of each individual atmospheric impurity and the amount of all (total) atmospheric impurities in the reagent gas before the reagent gas is added to the container or when the reagent gas is introduced to an injection station (e.g., as contained in reagent gas source 112) for loading into the container will be lower than the amount present in the reagent gas after adsorption and desorption on the sorbent in the container and upon delivery of the reagent gas from the storage container. During the processes of handling, processing, transporting, and packaging the reagent gas, additional atmospheric impurities are introduced into the reagent gas to produce a packaged supply of reagent gas.

[0083] The methods, techniques, and apparatus herein attempt to reduce or minimize the amount of atmospheric impurities to which the reagent gas is exposed during an injection step, such as from the time at or before the reagent gas is added to a storage vessel (e.g., after the reagent gas is contained in the reagent gas source 112a of injection station 110a in FIG. 1) to the time the reagent gas is contained in the vessel (for storage) and selectively delivered from the vessel for use. It is recognized herein that the amount of atmospheric impurities contained in the reagent gas selectively delivered from a storage vessel can be reduced by using techniques and apparatus designed to present reduced or minimal amounts of these impurities to the reagent gas after storage in the vessel, from the vessel itself, from adsorbents, and from the equipment and handling techniques used to transfer the reagent gas from a bulk gas source of reagent gas (e.g., sources 112a, b, c, or d in FIG. 1) to individual storage vessels from which the reagent gas can be stored, transported, and then selectively released for use.

[0084] FIG. 2 is a perspective cutaway view of a fluid delivery system (package) of the present disclosure in which the sorbent is contained in a container for reversibly storing a fluid (reagent gas) thereon.

[0085] As shown, the fluid delivery system 210 includes a container 212 having a cylindrical sidewall 214 and a floor at the bottom of the sidewall. The sidewall and floor enclose an interior volume 216 of the container in which a sorbent 218 is disposed. The sorbent 218 is of a type that has an adsorptive affinity for a desired reagent gas and is capable of desorbing the reagent gas under dispensing conditions for discharge from the container. The container 212 is joined at its upper end portion to a cap 220, which may have a flat feature at its periphery and may circumscribe an upwardly extending boss 228 at its upper surface. The cap 220 has a central threaded opening that receives a corresponding threaded lower portion 226 of a fluid dispensing system. While these particular structures are suitable and useful for the container as described and the delivery system as described, other alternative structures of the container and associated structures of the delivery system are known and useful as alternatives to those shown in FIG. 2.

[0086] Fluid dispensing system 210 includes a valve head 222 in which a fluid dispensing valve element (not shown in FIG. 2 ) is disposed, the fluid dispensing valve element being translatable between a fully open and a fully closed position by operation of a manually operated hand wheel 230 coupled thereto. The fluid dispensing system includes an outlet port 224 for dispensing fluid from a container when the valve is opened by operation of the hand wheel 230. In lieu of the hand wheel 230, the fluid dispensing system may include an automated valve actuator, such as a pneumatic valve actuator pneumatically actuable to translate a valve in the fluid dispensing system between a fully open and a fully closed valve position.

[0087] Outlet port 224 is defined by an open end of a corresponding tubular extension that communicates with a valve chamber in valve head 222 that contains a translatable valve element. Such a tubular extension may be threaded onto its exterior surface to accommodate coupling of the fluid dispensing system to a flow circuit for delivering dispensed fluid to a downstream point of use, such as, for example, a reagent gas-utilizing tool adapted for manufacturing semiconductor manufacturing products such as integrated circuits or other microelectronic devices, or a reagent gas-utilizing tool adapted for manufacturing solar panels or flat panel displays. Instead of a threaded feature, the tubular extension may be configured with other coupling structures, such as a quick coupling, or adapted for dispensing fluid to a point of use.

[0088] The sorbent 218 in the interior volume 216 of the container 212 may be of any suitable type as described herein, e.g., may be or include a sorbent in a powder, particulate, pellet, bead, monolith, tablet, or other suitable or useful form. The sorbent is selected to have an adsorption affinity for the reagent gas to be stored in the container during storage and transport conditions and selectively dispensed from the container under dispensing conditions. Such dispensing conditions may include, e.g., opening of a valve element in the valve head 222 to accommodate desorption of the fluid (reagent gas) stored in a form adsorbed on the sorbent and discharge of the fluid (reagent gas) from the container through the fluid dispensing system to an outlet port 224 and associated flow circuitry, where pressure at the outlet port 224 causes pressure-mediated desorption and discharge of the fluid from the fluid supply package. For example, the dispensing assembly may be coupled to a flow circuit at a pressure lower than the pressure inside the container for such pressure-mediated desorption and dispensing, e.g., a subatmospheric pressure suitable for a downstream reagent gas-utilizing tool coupled to the fluid supply package by the flow circuitry described above.

[0089] Alternatively, the dispense conditions may include opening a valve element in valve head 222 in conjunction with heating of sorbent 218 to cause thermally mediated desorption of the fluid (reagent gas) for discharge from the fluid supply package. Any other alternative or additional desorption mediated conditions and techniques, or any combination of such conditions and techniques, may also be used as desired.

[0090] The fluid supply package 210 (sorbent-based storage system) may be filled with fluid for storage on the sorbent to a desired pressure, which may be subatmospheric or superatmospheric, by any filling method. Fluid may be filled internally through outlet port 224. Alternatively, the valve head 222 may be provided with a separate fluid inlet port for filling the vessel.

[0091] The fluid (reagent gas) in the container may be stored at any suitable pressure condition. An advantage of using a sorbent as the fluid storage medium is that the fluid may optionally be stored at low pressure, for example sub-atmospheric or low super-atmospheric pressure, thereby enhancing the safety of the fluid supply package relative to fluid supply packages that store reagent gas at high pressure, similar to high pressure gas cylinders.

[0092] The fluid supply package of Figure 2 may be used with any of the sorbents described herein to provide an effective storage medium for the packaged reagent gas, from which the reagent gas may be selectively desorbed under dispensing conditions for delivery to a specific point of use or to a specific reagent gas utilization device. The reagent gas may be delivered from a container for use under dispensing conditions for use of the reagent gas in a manufacturing process. The process may be for processing semiconductor materials or microelectronic devices, with exemplary processes including, among others, ion implantation, epitaxial growth, plasma etching, reactive ion etching, metallization, physical vapor deposition, chemical vapor deposition, atomic layer deposition, plasma deposition, photolithography, cleaning, and doping.

[0093] The reagent gas may be one that is delivered for use in the manufacturing process of semiconductor products, flat panel displays, solar panels, or components or subassemblies thereof. The reagent gas may be any type of reagent gas useful as a feedstock for one of these processes, such as silane, disilane, germane, boron trifluoride, phosphine, arsine, diborane, acetylene, germanium tetrafluoride, silicon tetrafluoride, or another useful reagent gas. The reagent gas may also include a combination of two or more different gases, such as germanium tetrafluoride and hydrogen gas (H2), boron trifluoride and hydrogen gas, among others.

[0094] According to the useful and preferred storage systems described, as well as the methods and apparatus used to prepare the described storage systems, containers prepared to contain reagent gas by the described techniques can dispense reagent gases containing substantially less atmospheric impurities than previous commercially available sorbent-type storage systems. For example, the useful storage systems described can deliver reagent gases containing less than 150 ppmv, e.g., less than 50 ppmv, or less than 25, 15, or 10 ppmv of total atmospheric impurities, measured as the total (sum) of nitrogen (N2), carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), and water vapor (H2O). Useful and preferred storage systems are capable of delivering reagent gas that also has low levels of each of these atmospheric impurities measured individually, for example, reagent gas containing less than 25, 20, 15, 20, or 5 ppmv each of nitrogen (N2), carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), and water vapor (H2O) (measured individually).

[0095] Reagent gases stored in containers as described, which can be delivered containing relatively small amounts of atmospheric impurities compared to other storage systems, can improve the performance of semiconductor processing equipment ("tools") based on their lower levels of impurities.

[0096] Certain types of impurities in the reagent gas delivered to the tool can result in cross-contamination due to minimal or inadvertent communication between sources of reagent gas within the tool. The described systems and methods can control or minimize cross-contamination between reagent gases between storage vessels that are processed and injected using the described injection systems, including, for example, dedicated injection stations as shown in FIG. 1. Such systems are effective in reducing the likelihood of cross-contamination of different types of reagent gases between injected storage vessels. Controlling or reducing cross-contamination in this manner improves the performance of systems that use reagent gases injected and stored in storage vessels in the manner described herein.

[0097] As an example of the detrimental effects of cross-contamination of reagent gases between injected storage vessels, cross-contamination of one reagent gas in a storage vessel of the desired (different) reagent gas used for ion implantation can have a detrimental effect on the process, particularly the production of the ion beam produced, as evidenced by beam spectrum analysis. The beamline of an ion implanter separates ion species in atomic mass units (amu) via magnetic acceleration through a curved path to the tool. The beam is controlled to deliver a specific atomic mass unit species to the wafer surface for implantation. If a contaminant in the reagent gas (a cross-contaminant from another storage vessel injected using the storage system) is too close in atomic mass units to the desired species, the contaminant isotopic species (e.g., Carbon-12, 12 C) is the desired isotope species (e.g., boron-11, 11 B), the contaminating isotope species will be present in the ion beam along with the desired isotope species and will then be unintentionally implanted into the wafer. Carbon, which has an atomic mass unit of 12, can be a problematic contaminant for a beam tuned to deliver boron, which has an atomic mass unit of 11.

Claims

1. 1. A sorbent-based storage system for containing a reagent gas and a sorbent, the storage system comprising: a storage vessel containing an interior, a sorbent within the interior, and the reagent gas sorbed by the sorbent, the storage system comprising: Providing a sorbent; disposing an adsorbent within a vessel; exposing the adsorbent within the vessel to elevated temperatures and reduced pressures to remove residual moisture and volatile impurities; adding a reagent gas into the container at a low flow rate of less than 1000 sccm after exposing the adsorbent inside the container to high temperature and reduced pressure, whereby the reagent gas is adsorbed by the adsorbent; The device is configured to: A storage system is capable of dispensing reagent gas from a container, the dispensed reagent gas being CO, CO ２ , N ２ , C.H. ４ , and H ２ 2. A storage system comprising less than 150 ppm (by volume, ppmv) total impurities selected from:

2. A reagent gas can be dispensed from the container, the dispensed reagent gas being less than 25 ppm CO (by volume), less than 25 ppm CO (by volume), ２ , less than 25 ppm (by volume) N ２ , less than 25 ppm (by volume) ４ and less than 25 ppm (by volume) H ２ The storage system of claim 1 , further comprising one or more of:

3. A reagent gas can be dispensed from the container, the dispensed reagent gas being less than 10 ppm (by volume) CO, less than 10 ppm (by volume) CO ２ , less than 10 ppm (by volume) N ２ , less than 10 ppm (by volume) ４ and less than 10 ppm (by volume) H ２ The storage system of claim 1 , comprising two or more of O.

4. A reagent gas can be dispensed from the container, the dispensed reagent gas being less than 25 ppm CO, less than 25 ppm CO ２ , less than 25 ppm N ２ , less than 25 ppm CH ４ and less than 25 ppm H ２ The storage system of claim 1 , further comprising:

5. 10. The storage system of claim 1, wherein the adsorbent is a carbon-based adsorbent, a metal organic framework, or a zeolite.

6. 10. The storage system of claim 1, wherein the sorbent is in the form of granules, beads, pellets, or shaped monoliths.

7. 10. The storage system of claim 1, wherein the internal pressure of the vessel is less than 760 Torr.

8. 2. The storage system of claim 1, wherein the reagent gas is a hydride or a halide.

9. the hydride is selected from arsine, silane, germane, methane, and phosphine; The halide is BF ３ , SiF ４ , P.F. ３ , P.F. ５ , GeF ４ , and N.F. ３ Selected from: The storage system of claim 8.

10. 10. The storage system of claim 1, wherein the sorbent is in the form of particulates.

11. 1. A process for storing a reagent gas in a vessel containing a sorbent, comprising: Providing a sorbent; disposing an adsorbent within a vessel; exposing the adsorbent within the vessel to elevated temperatures and reduced pressures to remove residual moisture and volatile impurities; adding a reagent gas into the container at a low flow rate of less than 1000 sccm after exposing the adsorbent inside the container to high temperature and reduced pressure, whereby the reagent gas is adsorbed by the adsorbent; Including, A storage system is capable of dispensing reagent gas from a container, the dispensed reagent gas being CO, CO ２ , N ２ , C.H. ４ , and H ２ O, and combinations thereof in a total amount of less than 150 ppm.

12. storing a reagent gas in a container; and dispensing a reagent gas from a container, the dispensed reagent gas being CO, CO ２ , N ２ , C.H. ４ , and H ２ O, and combinations thereof, in a total amount of less than 50 ppm (by volume); 12. The process of claim 11.

13. Dispensing a reagent gas from a container, the dispensed reagent gas comprising less than 25 ppm CO (by volume), less than 25 ppm CO (by volume), ２ , less than 25 ppm (by volume) N ２ , less than 25 ppm (by volume) ４ and less than 25 ppm (by volume) H ２ The process of claim 11 , further comprising one or more of:

14. Dispensing a reagent gas from a container, the dispensed reagent gas comprising less than 25 ppm CO (by volume), less than 25 ppm CO (by volume), ２ , less than 25 ppm (by volume) N ２ , less than 25 ppm (by volume) ４ and less than 25 ppm (by volume) H ２ The process of claim 11 , comprising:

15. Before adding the reagent gas into the container, passivating the adsorbent by contacting the adsorbent with a passivating gas that includes a reagent gas; removing the passivating gas from the adsorbent after a period of time effective to passivate the adsorbent of from 15 to 2500 minutes; The process of claim 11 further comprising:

16. The method of claim 15, further comprising pyrolyzing the sorbent prior to disposing the sorbent within the vessel; 12. The process of claim 11, wherein placing the adsorbent inside the vessel is performed under an inert atmosphere within 30 minutes of completion of pyrolysis of the adsorbent while the adsorbent is at a temperature between 40° C. and 65° C. without exposing the pyrolyzed adsorbent to the ambient atmosphere.

17. Adding the reagent gas to the interior of the vessel in an amount sufficient to generate a pressure (Torr, absolute pressure) within the vessel that is at least 10% greater than the target pressure; The process is allowing the reagent gas to equilibrate at said pressure between the adsorbed reagent gas adsorbed on the adsorbent and the gaseous reagent gas contained in the headspace of the vessel; allowing the reagent gas to equilibrate and then removing a portion of the reagent gas to reduce the pressure therein to a target pressure; The process of claim 11 further comprising:

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