WO2007134183A2 - Chemical reagent delivery system utilizing ionic liquid storage medium - Google Patents

Abstract

A system (10) including a reagent supply container (12) in which a vessel (14) holds a composition including a chemical reagent dissolved or dispersed in a storage liquid (18) that is reversibly interactive with the chemical reagent to store the chemical reagent therein, and an ultrasonic energy source (19, 32, 34) adapted to introduce ultrasonic energy into the composition to liberate the chemical reagent therefrom for dispensing from the vessel of the reagent supply container. The ultrasonic energy source can be internally provided in the container, or may be provided as part of an external ultrasonic energy impingement unit (112), in which the stored chemical reagent, e.g., a microelectronic device manufacturing reagent, is extracted from the liquid storage medium for transport to a reagent-utilizing process or facility (38). The liquid storage medium may for example include an ionic liquid with which the chemical reagent is reversibly taken up, and subsequently released under ultrasonic energy exposure dispensing conditions.

Description

CHEMICAL REAGENT DELIVERY SYSTEM UTILIZING IONIC LIQUID

STORAGE MEDIUM

CROSS-REFERENCE TO RELATED APPLICATION

The benefit of priority of U.S. Provisional Patent Application 60/799,877 filed May 13, 2006 is hereby claimed. The disclosure of such priority provisional application is hereby incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

[0001] The present invention relates to material storage and delivery systems and methods, and to liquid storage media in which chemical reagents are reversibly storable.

DESCRIPTION OF THE RELATED ART

[0002] In the manufacture of microelectronic device products, including semiconductor devices and precursor structures, flat panel displays, etc., various materials are utilized as reagents in the manufacturing process.

[0003] Current methods to deliver reagents typically use heat to increase the vapor pressure of the source material and enhance the rate and extent of flux of the reagent to the manufacturing tool. For this purpose, the source material is provided in a supply package, also referred to as an ampoule or a vaporizer. The supply package frequently includes a vessel that is externally heated by wrapping of the vessel in heating tape or a heating blanket or thermal jacket. Alternatively, the package may be introduced into a furnace to supply the necessary heat for delivery of the chemical reagent.

[0004] Examples of such supply packages include the solid source delivery package commercially available from ATMI, Inc. (Danbury, CT, USA) under the trademark ProEvap, conventional bubblers used in the semiconductor manufacturing industry, and ampoules for supplying cluster boron materials for ion implantation. The reagent can be in any of solid, liquid or gaseous forms in specific applications, and may be incorporated in a storage medium from which the reagent is dispensed under appropriate dispensing conditions, for delivery to a process tool or other fluid-utilizing apparatus, process or facility.

[0005] Various of the aforementioned reagent supply packages utilize heating as an operational requirement for reagent delivery. Such heating, however, entails a number of disadvantages. [0006] A primary disadvantage is the time required for the vessel containing the chemical reagent source material to be heated up, along with the associated flow circuitry, including transfer lines, valves, restrictive flow orifice elements, and the like. The supply package therefore has an associated warm-up, heat-up time before the chemical reagent can be dispensed from the package.

[0007] Correspondingly, such heating, once established, creates a thermal ballast effect, as the heat capacity of the vessel, valve head, and other package components creates a thermal load that must be dissipated when the package is exhausted and must be changed out. The resulting cool-down to ambient temperature for change -out of the package may require significant time, which decreases the efficiency of the manufacturing operation. [0008] Another disadvantage entailed in heating of the vessel containing the chemical reagent source material is that the protracted heating of the material may cause thermal decomposition of the material. Such heating may also cause agglomeration of the reagent source material in instances in which the source material is provided in a discontinuous, e.g., finely divided, solid form. As a result, the agglomerated material provides less surface area for volatilization and a reduced delivery rate.

[0009] A further associated deficiency of heating the chemical reagent supply package is that heat tracing the flow circuitry and delivery system from the package to the downstream process tool can be difficult, time-consuming and susceptible to development of cold spots in the flow circuitry and delivery system that produce condensation of the chemical reagent that can lead to reduced delivery rate or even clogging of the process flow passages and inoperability of the system. In the case of pulsed flow atomic layer deposition (ALD), the pulsing sequence requires rapid opening and closing of valves in the flow circuitry, and such valves over time may clog or fail.

[0010] For all these reasons, heating of chemical reagent supply packages is costly, time- consuming, and introduces significant process inefficiencies and associated increased maintenance requirements.

[0011] There is accordingly a need in the art for chemical reagent source packages that avoid the numerous deficiencies associated with heating of the package.

[0012] The art has continued to develop a variety of chemical reagent supply packages in which reagents are stored on and dispensed from storage media. Examples of such storage media include physical adsorbents, such as the chemical reagent source packages commercially available from ATMI, Inc. (Danbury, CT, USA) under the trademarks SDS and VACSorb, and ionic media-based chemical reagent source packages of the type described in U.S. Patent Application Publication No. 20040206241 published October 21, 2004 in the names of Daniel Joseph Tempel, et al. for "Reactive Liquid Based Gas Storage and Dispensing Systems," and U.S. Patent Application Publication No. 20050276733 published December 15, 2005 in the names of Daniel Joseph Tempel, et al. for "Liquid Media Containing Lewis Acidic Reactive Compounds for Storage and Delivery of Lewis Basic Gases."

[0013] Considering ionic liquid storage media in greater detail, the desorption rate of chemical reagent gases dissolved in ionic liquids is typically rather poor, due to the fact that the gases are chemically bound to the fluid media by coordinative or ionic bonds. Chemical bonds are stronger and harder to break as compared to those involved in physical adsorption, and even vacuum desorption of fluid from ionic media may not be sufficient to deliver these fluids at the necessary rates for commercial manufacturing operations. The typical high viscosity of ionic liquid also tends to decrease the desorption rate.

[0014] Additionally, due to the strength of the bonds between the gas and the ionic medium, the use of ionic liquids as storage media for chemical reagents is also susceptible to the problem of high "heels," or residual chemical reagent that remains in the supply vessel, bound to the ionic liquid, when the vessel has reached a state where further removal of chemical reagent becomes uneconomic or impractical, and the supply vessel is regarded as being exhausted.

[0015] The art continues to seek improvements in ionic liquid-based reagent storage and delivery system that overcomes the aforementioned deficiencies.

SUMMARY OF THE INVENTION

[0016] The present invention relates to chemical reagent delivery systems and methods. [0017] In one aspect, the invention relates to a system comprising a reagent supply container including a vessel holding a composition including a chemical reagent dissolved or dispersed in a storage liquid that is reversibly interactive with the chemical reagent to store the chemical reagent therein, and an ultrasonic energy source arranged to introduce ultrasonic energy into said composition to liberate the chemical reagent therefrom for dispensing from the vessel of the reagent supply container.

[0018] In another aspect, the invention relates to a chemical reagent delivery system comprising a chemical reagent package including a vessel to which a dispensing assembly is coupled, wherein the vessel contains an ionic liquid in which the chemical reagent is stored, and from which it is disengaged and dispensed through the dispensing assembly under dispensing conditions involving ultrasonic energy impingement on the ionic liquid, and an ultrasonic energy source adapted to impinge ultrasonic energy on the ionic liquid to disengage the chemical reagent therefrom for dispensing thereof through the dispensing assembly. [0019] A further aspect of the invention relates to a method of chemical reagent delivery, comprising dissolving or dispersing a chemical reagent in a storage liquid to form a composition in which the chemical reagent is reversibly stored, applying ultrasonic energy to the composition to disengage the chemical reagent from the storage liquid in a volatilized form, and delivering the chemical reagent in the volatilized form to a locus of use of said chemical reagent.

[0020] Another aspect of the invention relates to a chemical reagent delivery method comprising providing a chemical reagent package including a vessel to which a dispensing assembly is coupled, wherein the vessel contains an ionic liquid in which the chemical reagent is stored, and from which it is disengaged and dispensed through the dispensing assembly under dispensing conditions involving ultrasonic energy impingement on the ionic liquid, and impinging ultrasonic energy on the ionic liquid to disengage the chemical reagent therefrom, and dispensing the disengaged chemical reagent through the dispensing assembly. [0021] In another aspect, the invention relates to a system comprising a reagent supply container including a vessel holding a composition including a chemical reagent dissolved or dispersed in a storage liquid that is reversibly interactive with the chemical reagent to store the chemical reagent therein in a storage state, and to release the chemical reagent from the storage liquid for dispensing from the vessel of the reagent supply container in a dispensing state, wherein the storage liquid has solid particles therein that are adapted to prevent supersaturation of the storage liquid.

[0022] A further aspect of the invention relates to a method of chemical reagent delivery, comprising dissolving or dispersing a chemical reagent in a storage liquid to form a composition in which the chemical reagent is reversibly stored in a storage mode of operation, releasing the chemical reagent from the storage liquid in a dispensing mode of operation, and delivering the released chemical reagent in a volatilized form to a locus of use of said chemical reagent, wherein the storage liquid has solid particles therein that are adapted to prevent supersaturation of the storage liquid.

[0023] Another aspect of the events relates to a system comprising a reagent supply container including a vessel holding a composition including a chemical reagent dissolved or dispersed in a storage liquid that is reversibly interactive with the chemical reagent to store the chemical reagent therein in a storage state, and to release the chemical reagent from the storage liquid for dispensing from the vessel of the reagent supply container in a dispensing state, wherein the storage liquid has solid particles therein that are adapted to remove impurities from the storage liquid.

[0024] The invention in another aspect relates to a method of chemical reagent delivery, comprising dissolving or dispersing a chemical reagent in a storage liquid to form a composition in which the chemical reagent is reversibly stored in a storage mode of operation, releasing the chemical reagent from the storage liquid in a dispensing mode of operation, and delivering the released chemical reagent in a volatilized form to a locus of use of said chemical reagent, wherein the storage liquid has solid particles therein that are adapted to remove impurities from the storage liquid.

[0025] Other aspects, features and embodiments of the invention will be more fully apparent from the ensuing disclosure and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 is a schematic representation of a chemical reagent delivery system according to one embodiment of the invention.

[0027] FIG. 2 is a schematic representation of a chemical reagent delivery system according to one embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION. AND PREFERRED EMBODIMENTS THEREOF

[0028] The present invention relates to a material storage and dispensing system, involving use of an ionic liquid storage medium.

[0029] In accordance with the present invention, chemical reagent is vaporized or nebulized for delivery, using ultrasonic energy.

[0030] Ultrasonic vaporizers convert electrical energy to rapid-rate mechanical vibrations, typically on the order of thousands to hundreds of thousands of Hertz. The resulting high frequency vibrations produce intense cavitation in fluids exposed to the ultrasonic energy.

Cavitation bubbles develop in the fluid. Such bubbles exhibit high temperature and pressure that produce vaporization or atomization of the fluid.

[0031] An illustrative ultrasonic vaporizer exhibiting the aforementioned characteristics is the Omron Model NE-U22 mesh type nebulizer commercially available from Omron

Healthcare, Inc. (Kyoto, Japan), as utilized for nebulizing liquid therapeutic agents for medical inhalation therapy. Nebulizers of such type generate a high throughput vapor without heating the bulk volume of the source liquid.

[0032] For microelectronic device manufacturing operations, liquid reagents can be readily vaporized by nebulizers. The resulting atomized material can be transported to the microelectronic device manufacturing tool using a carrier gas, or by use of vacuum, involving vacuum pumps, ejectors, eductors or the like. Solids delivery can be correspondingly carried out, by dissolving the solid reagent in a low vapor pressure liquid, such as an ionic liquid, mineral oil, silicon-based oil, fluorocarbon-based oil, etc. When solids are dispersed in the aforementioned media, ultrasonic energy applied to the dispersion will preferentially vaporize the more volatile component, i.e., the chemical reagent dispersed in such medium. [0033] In one aspect, the invention relates to a system comprising a reagent supply container including a vessel holding a composition including a chemical reagent dissolved or dispersed in a storage liquid that is reversibly interactive with the chemical reagent to store the chemical reagent therein, and an ultrasonic energy source arranged to introduce ultrasonic energy into said composition to liberate the chemical reagent therefrom for dispensing from the vessel of the reagent supply container.

[0034] The ultrasonic energy source can include any suitable type of source, such as an ultrasonic nebulizer, a piezoelectric ultrasonic nozzle, etc. The chemical reagent likewise can be of any suitable type, such as a reagent species selected from the group consisting of photoresists, etching agents, organometallic compounds, dielectric materials, and dopants. In one embodiment, the reagent supply container contains the ultrasonic energy source at least partially disposed in an interior volume of the vessel. Alternatively, the ultrasonic energy source can be located exteriorly of the reagent supply container.

[0035] The chemical reagent can be used for manufacturing a microelectronic device, such as a semiconductor structure, flat-panel display, or subassemblies for precursor structures therefor. For such purpose, the reagent supply container can be arranged in chemical reagent feed relationship to a microelectronic device manufacturing tool or other locus of use of the chemical reagent.

[0036] The reagent supply container can be coupled with the locus of use of the chemical reagent by flow circuitry, including typing, conduits, valving, manifolds, and associated process monitoring and control devices. In one embodiment, the reagent supply container is unheated other than by the ultrasonic energy source. The reagent supply container of such type can for example be arranged in chemical reagent feed relationship to a vapor deposition chamber in which the chemical reagent is contacted with a substrate for deposition of a film- forming material thereon, with the ultrasonic energy source being constituted by an ultrasonic vaporizer.

[0037] The chemical reagent delivery system of the convention permits delivery of the chemical reagent from the vessel of the reagent supply container at sub -atmospheric pressure, or other suitable pressure, appropriate to the process and end use of the chemical reagent. In a specific embodiment, the chemical reagent is flowed from the reagent supply container to a locus of use of the chemical reagent, wherein the locus of use comprises a chamber that is maintained at sub -atmospheric pressure.

[0038] In a specifically preferred embodiment, the storage liquid comprises a low vapor pressure liquid, e.g., a liquid selected from among ionic liquids, mineral oils, silicon-based oils and fluorocarbon-based oils. In applications in which the chemical reagent is used for atomic layer deposition, the ultrasonic energy source can be constituted by an ultrasonic vaporizer that is adapted for on-off switched operation for pulsed dispensing of the chemical reagent for atomic layer deposition.

[0039] The storage liquid utilized in the practice of the present invention can for example comprise a Lewis acid or Lewis base. The storage liquid can include a reactive ionic liquid, or any other liquid medium in which the chemical reagent of interest is storable in a reversible manner, including the ability to be stored in the liquid storage medium without degradation or decomposition, and to be extractable from the liquid storage medium under dispensing conditions, including ultrasonic energy exposure of the liquid storage medium containing the stored chemical reagent.

[0040] A further aspect of the invention relates to a method of chemical reagent delivery, comprising dissolving or dispersing a chemical reagent in a storage liquid to form a composition in which the chemical reagent is reversibly stored, applying ultrasonic energy to the composition to disengage the chemical reagent from the storage liquid in a volatilized form, and delivering the chemical reagent in the volatilized form to a locus of use of said chemical reagent.

[0041] Another aspect of the invention relates to a chemical reagent delivery method comprising providing a chemical reagent package including a vessel to which a dispensing assembly is coupled, wherein the vessel contains an ionic liquid in which the chemical reagent is stored, and from which it is disengaged and dispensed through the dispensing assembly under dispensing conditions involving ultrasonic energy impingement on the ionic liquid, and impinging ultrasonic energy on the ionic liquid to disengage the chemical reagent therefrom, and dispensing the disengaged chemical reagent through the dispensing assembly.

[0042] The approach of nebulization delivery of chemical reagents in accordance with the present invention entails the following advantages over the existing state of the art.

[0043] First, there is no need to heat the bulk source material, and on-off sequences for atomic layer deposition applications can be conducted in less than one second, thereby rendering the ALD process highly compact in temporal character, and highly efficient in general character. The pulsing of the material for ALD can be performed by switching the nebulizer on and off, without the need for additional valves.

[0044] Further, the localized vaporization involved in nebulization obviates decomposition issues that occur in conventional reagent delivery in microelectronic device manufacturing operations.

[0045] Additionally, the need to heat trace the entire reagent transport system from the source to the process tool can be eliminated if the atomized material is transferred to the tool at sufficient volumetric flow rate to avoid settling of the nebulized particles. [0046] In general, ultrasonic generation of volatilized reagent for deposition of the deposited species of the reagent is a cleaner and simpler approach to vaporization of the source material than the prior approach of heating the supply vessel containing the source material, and consumes less energy than such heating techniques.

[0047] Ultrasonic generation of volatilized reagent also entails the advantage that material delivery rates can be controlled in a simple and ready manner, by changing the intensity and/or frequency of the ultrasonic vibration.

[0048] Thus, the invention contemplates dissolution of chemical reagent material in an ionic liquid, and the extraction of such chemical reagent from the ionic liquid for dispensing, using ultrasonic energy that is impinged on such liquid to effect disengagement of the chemical reagent from the liquid storage medium.

[0049] The invention in one embodiment relates to a chemical reagent package including a vessel to which a dispensing assembly is coupled, wherein the vessel contains an ionic liquid in which the chemical reagent is stored, and from which it is disengaged and dispensed under dispensing conditions involving ultrasonic energy impingement on the ionic liquid. [0050] The invention also contemplates chemical reagent package arrangements in which an ultrasonic vaporizer is interiorly disposed in the vessel of the package, to generate piezoelectric vibration therein for liberation of the chemical reagent from the ionic liquid storage medium, for discharge from the package through the dispensing assembly. [0051] In another embodiment, the ionic fluid containing the chemical reagent dissolved therein can be transferred from the vessel of the chemical reagent package, into an external ultrasonic device to effect extraction of the chemical reagent from the liquid, so that the thus- separated chemical reagent in fluid form can be flowed to the downstream locus of use. [0052] The ionic liquid in which the chemical reagent is stored, and from which the chemical reagent is liberated under dispensing conditions involving ultrasonic energy impingement on the ionic liquid, may be of any suitable type. Illustrative ionic liquids includes those described in the aforementioned U.S. Patent Application Publication No. 20040206241 published October 21, 2004 in the names of Daniel Joseph Tempel, et al. for "Reactive Liquid Based Gas Storage and Dispensing Systems," and U.S. Patent Application Publication No. 20050276733 published December 15, 2005 in the names of Daniel Joseph Tempel, et al. for "Liquid Media Containing Lewis Acidic Reactive Compounds for Storage and Delivery of Lewis Basic Gases," the disclosures of which hereby are incorporated herein by reference, in their respective entireties.

[0053] The ionic liquid can serve as a reactive liquid, e.g., as a Lewis acid or Lewis base, to effect reversible reaction with the chemical reagent to be stored. Reactive ionic liquids include cationic and anionic components, in which the acidity or basicity of the reactive ionic liquid is governed by the acid or base strength of the cation, the anion, or by a combination of the two. Ionic liquids potentially useful in the broad practice of the present invention include, without limitation, salts of alkylphosphonium, alkylammonium, N-alkylpyridinium and N,N'- dialkylimidazolium cations. Common cations contain d- Ci₈ alkyl groups, and include the ethyl, butyl and hexyl derivatives of N-alkyl-N'-methylimidazolium and N-alkylpyridinium. Other cations include pyridazinium, pyrimidinium, pyrazinium, pyrazolium, triazolium, thiazolium, and oxazolium, as well as ethylammonium and piperidinium. [0054] Also potentially useful in the broad practice of the present invention are "task- specific" ionic liquids bearing reactive functional groups on the cation. Such ionic liquids can be prepared using functionalized cations containing a Lewis base or Lewis acid functional group. Task specific ionic liquids include aminoalkyl, such as aminopropyl; ureidopropyl, and thioureido derivatives of the above cations. Specific examples of task-specific ionic liquids containing functionalized cations include salts of l-alkyl-3-(3-aminopropyl)imidazolium, 1- alkyl-3-(3-ureidopropyl)- imidazolium, l-alkyl-3-(3-thioureidopropyl)imidazolium, l-alkyl-4- (2-diphenylphosphanylethyl)pyridinium, l-alkyl-3-(3-sulfopropyl- )imidazolium, and trialkyl- (3-sulfopropyl)phosphonium. Other groups that can be added in place of alkyl groups include alkoxyalkyl and alkylthioalkyl, e.g., methoxyethyl or ethoxyethyl, and methylthiotethyl or ethylthioethyl. These latter groups provide a mild basic reactivity toward metal compounds, while keeping melting points and viscosities relatively low.

[0055] A wide variety of anions can be matched with the cation component of such ionic liquids for achieving Lewis acidity. One type of anion is derived from a metal halide. The halide most often used is chloride although other halides may also be used. Preferred metals for supplying the anion component, e.g. the metal halide, include copper, aluminum, iron, zinc, tin, antimony, titanium, niobium, tantalum, gallium, and indium. Bismuth halides are also advantageous for providing low melting points combined with mild Lewis acidity. Examples of metal chloride anions include CuCl₂ ^", Cu2Cl₃\ AlCl₄ ^", A12C1₇ ^", ZnCl₃ ^", ZnCl₄ ^2", Zn₂Cl₅ ^", FeCl₃ ^", FeCl₄ ^", Fe₂Cl₇ ^", TiCl₅ ^", TiCl₆ ^2", SnCl₅ ^", SnCl₆ ^2", etc. For fluoride systems with low to moderate volatility, species derived from SbF₅ and SbF₃ are notable, e.g. Sb₂F₁₁ ^" as an acidic entity. In general, bi- or multinuclear halide ions which include halide atoms shared by two metals, e.g., Al- -Cl- -Al or Sb- F-- Sb, have Lewis acid activity.

[0056] As is known in the synthesis of ionic liquids, the type of metal halide and the amount of the metal halide employed has an effect on the acidity of the ionic liquid. For example, when aluminum trichloride is added to a chloride precursor, the resulting anion may be in the form AlCl₄ ^" or Al₂Cl₇ ^". The two anions derived from aluminum trichloride have different acidity characteristics, and these differing acidity characteristics affect the type of gases that can be reactively stored. [0057] Room temperature ionic liquids, or low melting temperature ionic liquids (typically melting below 100⁰C) can be formed by reacting a halide compound of the cation with an anion supplying reactant.

[0058] Examples of halide compounds from which Lewis acidic or Lewis basic ionic liquids can be prepared include:

1 -Ethyl-3-methylimidazolium bromide;

1 -Ethyl-3-methylimidazolium chloride;

1 -Butyl-3-methylimidazolium bromide;

1 -Butyl-3-methylimidazolium chloride;

1 -Hexyl-3-methylimidazolium bromide;

1 -Hexyl-3-methylimidazolium chloride;

1 -Methyl-3 -octylimidazolium bromide;

1 -Methyl-3 -octylimidazolium chloride;

Monomethylamine hydrochloride;

Trimethylamine hydrochloride;

Tetraethylammonium chloride;

Tetramethyl guanidine hydrochloride;

N-Methylpyridinium chloride;

N-Butyl-4-methylpyridinium bromide;

N-Butyl-4-methylpyridinium chloride;

Tetrabutylphosphonium chloride; and

Tetrabutylphosphonium bromide.

[0059] When the system is used for storing phosphine or arsine, a preferred reactive liquid is an ionic liquid and the anion component of the reactive liquid is a cuprate or aluminate and the cation component is derived from a dialkylimidazolium salt. Another anion component that may be useful in connection with phosphine and arsine is Ga₂Cl₇ ^".

[0060] Many low-melting, low vapor pressure reactive liquids having Lewis acid character can also be formed around oxygen-containing functional groups. For instance, mixtures of phosphoric acid with pyrophosphoric or metaphosphoric acid have very low vapor pressure and are highly acidic. Some alkylammonium salts display a moderate acidity through their protonated ammonium entity, e.g., ethylammonium nitrate. Single-charged ions of bi- or multiprotic acids, such as HSCV or H₃P₂O₇ ^", can form relatively low melting salts and have substantial acidic activity due to their remaining protons. Additionally, low-melting salts of organic acids containing a weakly basic anion and a strongly acidic cation can be used as Lewis acids. For instance, many metal salts of 2-ethylhexanoic acid (also known as octoates) have low melting points. By way of example, zinc 2-ethylhexanoate is one of several octoates that are liquids at room temperature, and can be used as a Lewis acid due to the acidity of the zinc ion. Some organic sulfonate and phosphonate salts may be used in similar fashion. [0061] It should be understood that in formulating a liquid phase for the purpose of this application it is not necessary for the "reactive liquid" to be actually liquid at room temperature, or at the actual process temperature. All that is necessary is that its melting point be low enough that, with the addition of another low-melting, low-vapor-pressure compound, the combined formulation will have the desired melting point. The practical limits on designing such mixtures are dictated by the mutual solubility of the compounds, by their melting points and cryoscopic constants, by their chemical compatibility, and by the minimum concentration of the reactive liquid that is deemed practical for achieving the desired capacity of the storage and delivery device.

[0062] Gases having Lewis basicity to be stored in and delivered from Lewis acidic reactive liquids, e.g., ionic liquids, may comprise one or more of phosphine, pentaborane, arsine, stibene, ammonia, hydrogen sulfide, hydrogen selenide, hydrogen telluride, isotopically- enriched analogs, basic organic or organo metallic compounds, etc. In addition to gases, nongaseous materials may be stored in and delivered from the liquid storage medium. For example, the material stored in and delivered from the liquid storage medium can itself be a liquid. Such stored and subsequently delivered liquid may for example be a liquid that under storage conditions is miscible with the liquid storage medium, and that under dispensing conditions is immiscible with the liquid storage medium, e.g., forming a phase-separated liquid volume from which the phase-separated liquid is discharged from the associated storage and dispensing vessel. Alternatively, the material stored in and delivered from the liquid storage medium can be a solid that is solubilized or suspended in the liquid storage medium, and subsequently released from the liquid storage medium under dispensing conditions. [0063] With reference to Lewis basic ionic liquids, which are useful for chemically complexing Lewis acidic gases, the anion or the cation component or both of such ionic liquids can be Lewis basic. In some cases, both the anion and cation are Lewis basic. Examples of Lewis basic anions include carboxylates, e.g., 2-ethylhexanoate, fluorinated carboxylates, sulfonates, fluorinated sulfonates, imides, borates, sulfates, phosphates, chloride, partially protonated ions derived from polyprotic acids, etc. Common anion forms include BF₄ ^", PF₆ ^", AsF₆ ^", SbF₆ ^", CH3COO^", CF3COO^", CF₃SO₃ ^", P-CH₃-C₆H₄SO₃ ^", (CF₃SO₂)₂N\ (NC)₂N^", (CF₃SO₂)₃C\ chloride, and F(HF)_n ^". Other anions include organo metallic compounds such as alkylaluminates, and alkyl- or arylborates. Preferred anions include BF₄ ^", p-CH₃-C₆H₄SO₃ ^", CF₃SO₃ ^", (CF₃SOz)₂N^", (NC)₂N-(CF₃SO₂)₃C\ CH₃COO^" and CF₃COO^". Other useful anions include: R-O-SO₃ ^" (alkyl sulfates), e.g. ethyl sulfate, CH₃CH₂-O-SO₃ ^" (the respective salts are easily made); and (RO)₂P(O)O^" (dialkylphosphate) as moderately weak bases, e.g., dibutylphosphate, and wherein R in the foregoing formulae is alkyl. [0064] Ionic liquids comprising cations that contain Lewis basic groups may also be used in storing gases having Lewis acidity. Examples of Lewis basic cations include rings with multiple heteroatoms. A Lewis basic group may also be part of a substituent on either the anion or cation. Potentially useful Lewis basic substituent groups include amine, phosphine, ether, carbonyl, nitrile, thioether, alcohol, thiol, etc.

[0065] Gases having Lewis acidity to be stored in and delivered from Lewis basic reactive liquids, e.g., ionic liquids, may comprise one or more of diborane, boron trifluoride, boron trichloride, SiF₄, germane, hydrogen cyanide, HF, HCl, Hl, HBr, GeF₄, isotopically-enriched analogs, acidic organic or organometallic compounds, etc. Like borane, several metallic hydrides of interest exhibit Lewis-acid activity and stabilization, including alane, gallane, stibine and indane. Halogens also have Lewis acid activity, specifically with respect to halide anions, and form polyhalide ions of low to moderate stability. The salts of these polyhalide ions often have melting points similar to, or lower than, the simple halide salts from which they are derived. Thus, ionic liquids in halide form can be used for safe storage and controlled delivery of bromine in Br₃ ^" form, of iodine in I₃ ^" or I₅ ^" or I₇ ^" form, and of chlorine in ICl₄ ^" form. [0066] In addition, the two-electron oxidation of some main-group metals and metalloids by halogens from their intermediate to their highest oxidation state (e.g., PbCl₂ to PbCl₄, TlCl to TlCl₃, and AsCl₃ to AsCl₅) can also be viewed as a Lewis acid-base reaction, and some of these oxidation systems are candidates for storage and delivery of halogens through a halide- containing anion.

[0067] Nonvolatile covalent liquids containing Lewis acidic or Lewis basic functional groups are also useful as reactive liquids for chemically complexing gases. Such liquids may include discrete organic or organometallic compounds, oligomers, low molecular weight polymers, branched amorphous polymers, natural and synthetic oils, etc.

[0068] Examples of liquids bearing Lewis acid functional groups include substituted boranes, borates, aluminums, or alumoxanes; protic acids such as carboxylic and sulfonic acids, and complexes of metals such as titanium, nickel, copper, etc.

[0069] Examples of liquids bearing Lewis basic functional groups include ethers, amines, phosphines, ketones, aldehydes, nitrites, thioethers, alcohols, thiols, amides, esters, ureas, carbamates, etc. Specific examples of reactive covalent liquids include tributylborane, tributyl borate, triethylaluminum, methanesulfonic acid, trifluoromethanesulfonic acid, titanium tetrachloride, tetraethyleneglycol dimethylether, trialkylphosphine, trialkylphosphine oxide, polytetramethyleneglycol, polyester, polycaprolactone, poly(olefin-alt-carbon monoxide), oligomers, polymers or copolymers of acrylates, methacrylates, or acrylonitrile, etc. In many cases, these liquids suffer from excessive volatility at elevated temperatures and are not suited for thermal-mediated evolution. However, they may be suited for pressure-mediated evolution. [0070] Solutions of gases in liquid can easily become supersaturated due to pressure and temperature fluctuations. This is true of low- viscosity liquids such as water, and it becomes an even more serious issue for viscous liquids, since the nucleation rate of new phases is a strong inverse function of viscosity. Supersaturation eventually ends with formation and bursting of large bubbles, a process that can lead to undesirable fluctuations in the gas pressure above the liquid.

[0071] Supersaturation can be minimized by promoting gas nucleation. This goal is best achieved by adding to the liquid an amount of high surface area solid particles that are insoluble and inert under the operating conditions. Typical examples include microporous carbon particles, silica particles, ceramic honeycombs, and alumina granules. Preferably the particles are made of a material with relatively high thermal conductivity and low reactivity, such as carbon, alumina or silicon carbide. Optionally, the solid phase and the liquid phase may both be interconnected, with the solid phase in effect serving as a "support" and the liquid being an "affinity medium" in the manner described in U.S. Patent 6,027,547, and with gas bubbles percolating through the liquid between the solid support particles. However, a small amount of solid "boiling chips" may be sufficient.

[0072] The bursting of liquid bubbles due to local supersaturation also poses a filtration problem. The delivery system therefore is preferably designed to filter out any aerosol droplets of the ionic liquid that are formed by the "boiling" process involving the extraction of the chemical reagent from the ionic liquid. The filtration can be accomplished in any suitable manner, e.g., using conventional filtration equipment and techniques applicable to filtering of aerosols.

[0073] While some ionic liquids are in liquid state at room temperature, e.g., 25°C, there are many ionic liquid species that are not. Furthermore, some ionic liquids may freeze during transit. Loading the reactive liquid with gaseous chemical reagent can also increase the melting temperature of the mixture, especially when a stoichiometric composition is approached. The ionic liquid system may therefore often be below its equilibrium freezing point. Nonetheless, whether or not the material inside the supply vessel actually freezes is difficult to predict, because of the tendency of viscous liquids to supercool.

[0074] To ensure that the reactive liquid is completely (or mostly) melted, the system may be maintained for a reasonable period of time above the highest melting point in the relevant part of the phase diagram of the reactive liquid and reactive gas; however, such approach is time-consuming and restricts the operating temperature range. Alternatively, and more desirably, electrode probes can be supplied for impedance measurements, since typically the resistivity of ionic solids is many orders of magnitude above that of the corresponding liquids. The impedance across the canister at several points can then be monitored, e.g., after transit, during refilling, and periodically during use. Such approach has the added benefit that it can also diagnose poorly controlled bubbling, by having a pair of electrodes positioned at the level of the upper layer of the liquid. Yet another approach, which avoids any necessity of inserting electrical leads into the vessel for impedance measurement, is the use of acoustic sensing techniques.

[0075] An intrinsic problem with ionic liquids having very low vapor pressure and low melting point is purity. Such liquids are difficult to purify by distillation techniques, and typically recrystallization purification is not possible or practical. As a result, many reactive liquid useful for the practice of the present invention contain various impurities, some of them volatile, which are hard to remove. Accordingly, reactive liquids should be selected based on their amenability to purification by vacuum evaporation techniques (e.g., by successive freeze- thaw cycles under high vacuum), taking into account vapor pressures, and whether or not a well-defined melting point exists.

[0076] To resolve the problems of bubble nucleation and residual impurities, it may be desirable to incorporate a high surface area solid capable of acting as a strong adsorbent for the impurities in the reactive liquid. For example, microporous carbon beads can be used, both to nucleate gas bubbles as needed and to strongly adsorb residual unsaturated nitrogen compounds such as imidazoles and pyridines which often constitute the main residual impurities in ionic liquids. Alternatively, or additionally, thoroughly dried alumina or silica can be added to the ionic liquid in order to remove residual water and other impurity species having affinity for the alumina or silica.

[0077] In another aspect, the invention relates to a system comprising a reagent supply container including a vessel holding a composition including a chemical reagent dissolved or dispersed in a storage liquid that is reversibly interactive with the chemical reagent to store the chemical reagent therein in a storage state, and to release the chemical reagent from the storage liquid for dispensing from the vessel of the reagent supply container in a dispensing state, wherein the storage liquid has solid particles therein that are adapted to prevent supersaturation of the storage liquid.

[0078] The solid particles may be of any type, e.g., carbon particles, silica particles, ceramic honeycombs, silicon carbide particles and alumina particles. The system optionally can further comprise a phase monitor arranged to monitor storage liquid in the reagent supply container to verify phase state thereof. The phase monitor can include at least one impedance sensor arranged to sense impedance of the storage liquid. In one embodiment, the phase monitor comprises an acoustic sensor.

[0079] In another embodiment, the storage liquid contains porous carbon beads. In yet another embodiment, the reagent supply system is provided as part of a microelectronic device manufacturing facility. The system in a further embodiment includes a storage liquid that comprises an ionic liquid. [0080] A further aspect of the invention relates to a method of chemical reagent delivery, comprising dissolving or dispersing a chemical reagent in a storage liquid to form a composition in which the chemical reagent is reversibly stored in a storage mode of operation, releasing the chemical reagent from the storage liquid in a dispensing mode of operation, and delivering the released chemical reagent in a volatilized form to a locus of use of said chemical reagent, wherein the storage liquid has solid particles therein that are adapted to prevent supersaturation of the storage liquid. Such method may constitute part of a process of microelectronic device manufacturing. The liquid employed as storage liquid in such method may include an ionic liquid.

[0081] Another aspect of the events relates to a system comprising a reagent supply container including a vessel holding a composition including a chemical reagent dissolved or dispersed in a storage liquid that is reversibly interactive with the chemical reagent to store the chemical reagent therein in a storage state, and to release the chemical reagent from the storage liquid for dispensing from the vessel of the reagent supply container in a dispensing state, wherein the storage liquid has solid particles therein that are adapted to remove impurities from the storage liquid.

[0082] The solid particles in such a system can be of any suitable type, e.g., carbon particles, silica particles, ceramic honeycombs, silicon carbide particles and alumina particles. The system may employ solid particles comprising porous carbon beads, and the system may be part of a microelectronic device manufacturing facility. The storage liquid in such system can comprise an ionic liquid.

[0083] The invention in another aspect relates to a method of chemical reagent delivery, comprising dissolving or dispersing a chemical reagent in a storage liquid to form a composition in which the chemical reagent is reversibly stored in a storage mode of operation, releasing the chemical reagent from the storage liquid in a dispensing mode of operation, and delivering the released chemical reagent in a volatilized form to a locus of use of said chemical reagent, wherein the storage liquid has solid particles therein that are adapted to remove impurities from the storage liquid.

[0084] The solid particles can be of any suitable type, including, for example, carbon particles, silica particles, ceramic honeycombs, silicon carbide particles and alumina particles. The foregoing method may be part of a process of microelectronic device manufacturing. The storage liquid in such method can comprise an ionic liquid.

[0085] Referring now to the drawings, FIG. 1 is a schematic representation of a chemical reagent delivery system 10 according to one embodiment of the invention. [0086] The chemical reagent delivery system 10 includes a chemical reagent storage and delivery container 12 including a vessel 14 defining an interior volume 16 therein. In the interior volume 16 is contained a volume of an ionic liquid 18 having a chemical reagent dissolved or dispersed therein.

[0087] The chemical reagent storage and delivery container 12 includes a nebulization and dispensing head assembly 22 coupled to the upper end of the vessel 14, e.g., by welding, brazing, mechanical coupling, or the like. The head assembly 22 includes a fill port 24 for introducing the ionic fluid storage medium and chemical reagent into the interior volume 16 of the vessel 14. The ionic fluid storage medium and the chemical reagent can be introduced into the vessel in sequential fashion, with the ionic liquid being introduced first, followed by introduction of the chemical reagent to the interior volume for solubilization in the ionic liquid therein. Alternatively, the chemical reagent may be mixed with the ionic liquid in a mixing chamber or container, to form the solution or dispersion of the chemical reagent and ionic liquid, and the resulting solution or dispersion can then be introduced into the vessel interior volume through the fill port 24.

[0088] The head assembly 22 further includes a dispensing tube 17 extending downwardly into the interior volume of the vessel, for flow of the chemical reagent vapor 30 through the dispensing tube 17 and an associated interior passage (not shown) in the head assembly main body portion to the discharge line 36 joined in closed flow communication with such interior passage.

[0089] The head assembly 22 also includes an ultrasonic nebulizer 19 disposed at least partially in the interior volume 16 of the vessel 14, and arranged to impinge ultrasonic waves 28 on the ionic liquid 18 containing the chemical reagent, to effect disengagement of the chemical reagent from the ionic liquid, producing the liberated vapor 30. The ultrasonic nebulizer 19 is powered by a power supply 34 coupled with the head assembly 22 by power supply line 32.

[0090] The liberated chemical reagent vapor then flows in discharge line 36 to the process tool 38, which in this illustrative embodiment comprises a vapor deposition chamber defining an interior volume 40 containing wafer 44 mounted on substrate support 46. By this arrangement, the wafer 44 is mounted on the support 46 so that it is contacted by the nebulized vapor 42, to form a film on the wafer from the active deposition species in the chemical reagent.

[0091] The process tool 38 is coupled to pump 50 by exhaust line 48. The pump 50 is arranged to impose a vacuum on the process tool, and thereby to draw the chemical reagent vapor into the process tool chamber. In lieu of a vacuum pump, the system could use another type of fluid driver, such as an eductor, ejector, blower, fan, compressor, or the like. [0092] By the foregoing arrangement, the chemical reagent is able to be dispensed at sub- atmospheric pressure, thereby increasing the safety of the system in relation to a conventional system utilizing high pressure gas cylinders for supply of pressurized gas to the process tool. [0093] In the chemical reagent supply vessel 14, the impingement of ultrasonic waves on the ionic liquid disengages the chemical reagent from the ionic liquid in a highly efficient manner, without the need of heating of the vessel 14 and associated process flow circuitry. [0094] Instead of an ultrasonic wave generator, the chemical reagent delivery system of FIG. 1 may employed a piezoelectric ultrasonic nozzle that is disposed in the interior volume 16 of the vessel 14, and is coupled with a siphon tube or other ionic liquid feed arrangement for feeding to the nozzle the ionic liquid containing the chemical reagent therein. [0095] FIG. 2 is a schematic representation of a chemical reagent delivery system 100 according to another embodiment of the invention.

[0096] The chemical reagent delivery system 100 includes a reactive liquid storage container 102 joined to feed line 104 and feeding pump 106 with reactive liquid containing chemical reagent dispersed or dissolved therein. The pump flows the reactive liquid dispersion or solution to the disengagement chamber 110, in which the liquid dispersion or solution may pass through an ultrasonic nozzle (not shown in FIG. 2). Alternatively, the chamber 110 may be arranged with an ultrasonic energy source 112 that is actuated to generate ultrasonic waves 114 that are impinged on the liquid dispersion or solution, to cause such dispersion or solution to release the chemical reagent therefrom, as a consequence of the input of the ultrasonic energy to the dispersion or solution.

[0097] The chemical reagent thereby is volatilized and flows from the disengagement chamber 110 in line 116 to the process tool 122 or other fluid-utilizing process equipment. [0098] From the process tool 122, the unused volatilized chemical reagent is flowed in effluent line 124 to effluent abatement facility 126, which may for example comprise wet and/or dry scrubbing, neutralization, oxidation treatment, chemical reaction abatement, or the like, serving to abate hazardous gas species in the effluent stream from the process tool 122. [0099] It will therefore be appreciated that the present invention provides a simple and efficient alternative to the prior art approach of bulk heating of the reagent supply vessel and associated piping, valves, manifolds, etc. As a result, the chemical reagent is not exposed to sustained elevated temperature conditions that can degrade and decompose the reagent. Additionally, the ultrasonic volatilization of the chemical reagent in the system of the invention facilitates change-out of chemical reagent containers without the need to await cool- down of a hot vessel before a fresh container can be installed, and avoids the need for warm- up/heat-up of the vessel that is a major deficiency of prior art chemical reagent vapor generation systems. [00100] While the invention has been has been described herein in reference to specific aspects, features and illustrative embodiments of the invention, it will be appreciated that the utility of the invention is not thus limited, but rather extends to and encompasses numerous other variations, modifications and alternative embodiments, as will suggest themselves to those of ordinary skill in the field of the present invention, based on the disclosure herein. Correspondingly, the invention as hereinafter claimed is intended to be broadly construed and interpreted, as including all such variations, modifications and alternative embodiments, within its spirit and scope.

Claims

THE CLAIMS What is claimed is:

1. A system comprising a reagent supply container including a vessel holding a composition including a chemical reagent dissolved or dispersed in a storage liquid that is reversibly interactive with the chemical reagent to store the chemical reagent therein, and an ultrasonic energy source arranged to introduce ultrasonic energy into said composition to liberate the chemical reagent therefrom for dispensing from the vessel of the reagent supply container.

2. The system of claim 1, wherein the storage liquid comprises an ionic liquid.

3. The system of claim 1, wherein the ultrasonic energy source comprises an ultrasonic nebulizer.

4. The system of claim 1, wherein the ultrasonic energy source comprises a piezoelectric ultrasonic nozzle.

5. The system of claim 1, wherein the chemical reagent includes a reagent species selected from the group consisting of photoresists, etching agents, organometallic compounds, dielectric materials, and dopants.

6. The system of claim 1, wherein the reagent supply container contains the ultrasonic energy source at least partially disposed in an interior volume of the vessel.

7. The system of claim 1, wherein the ultrasonic energy source is located exteriorly of the reagent supply container.

8. The system of claim 1, wherein the reagent supply container is arranged in chemical reagent feed relationship to a microelectronic device manufacturing tool.

9. The system of claim 1, wherein the reagent supply container is arranged in chemical reagent feed relationship to a locus of use of said chemical reagent.

10. The system of claim 9, wherein the reagent supply container is coupled with the locus of use of the chemical reagent by flow circuitry.

11. The system of claim 1 , wherein the reagent supply container is unheated other than by the ultrasonic energy source.

12. The system of claim 1, wherein the reagent supply container is arranged in chemical reagent feed relationship to a vapor deposition chamber in which the chemical reagent is contacted with a substrate for deposition of a film-forming material thereon.

13. The system of claim 1, wherein the ultrasonic energy source comprises an ultrasonic vaporizer.

14. The system of claim 1, wherein the chemical reagent is dispensed from the vessel of the reagent supply container at sub -atmospheric pressure.

15. The system of claim 1, wherein the chemical reagent is flowed from the reagent supply container to a locus of use of the chemical reagent and the locus of use comprises a chamber that is maintained at sub -atmospheric pressure.

16. The system of claim 1, wherein the storage liquid comprises an ionic liquid.

17. The system of claim 1, wherein the storage liquid comprises a liquid selected from the group consisting of ionic liquids, mineral oils, silicon-based oils and fluorocarbon-based oils.

18. The system of claim 1, wherein the ultrasonic energy source comprises an ultrasonic vaporizer adapted for on-off switched operation for pulsed dispensing of the chemical reagent for atomic layer deposition.

19. A chemical reagent delivery system comprising a chemical reagent package including a vessel to which a dispensing assembly is coupled, wherein the vessel contains an ionic liquid in which the chemical reagent is stored, and from which it is disengaged and dispensed through the dispensing assembly under dispensing conditions involving ultrasonic energy impingement on the ionic liquid, and an ultrasonic energy source adapted to impinge ultrasonic energy on the ionic liquid to disengage the chemical reagent therefrom for dispensing thereof through the dispensing assembly.

20. The system of claim 19, wherein an ultrasonic vaporizer comprises said ultrasonic energy source, and is interiorly disposed in the vessel of the package.

21. The system of claim 19, wherein an ultrasonic vaporizer comprises said ultrasonic energy source, and is exteriorly disposed in relation to the vessel of the package.

22. The system of claim 19, wherein the ionic liquid is transferred from the vessel to an ultrasonic energy impingement chamber for impingement of ultrasonic energy thereon, to disengage the chemical reagent therefrom for dispensing thereof through the dispensing assembly.

23. The system of claim 1, wherein the storage liquid comprises a Lewis acid or Lewis base.

24. The system of claim 1, wherein the storage liquid comprises a reactive ionic liquid.

25. The system of claim 1, wherein the storage liquid comprises at least one of salts of alkylphosphonium, alkylammonium, N-alkylpyridinium and N,N'-dialkylimidazolium cations.

26. The system of claim 1, wherein the storage liquid comprises a liquid selected from among ethyl, butyl and hexyl derivatives of N-alkyl-N'-methylimidazolium and N-alkylpyridinium.

27. The system of claim 1, wherein the storage liquid comprises a cation selected from among pyridazinium, pyrimidinium, pyrazinium, pyrazolium, triazolium, thiazolium, oxazolium, ethylammonium and piperidinium.

28. The system of claim 1, wherein the storage liquid comprises an ionic liquid selected from the group consisting of salts of l-alkyl-3-(3-aminopropyl)imidazolium, l-alkyl-3-(3- ureidopropyl)- imidazolium, l-alkyl-3-(3-thioureidopropyl)imidazolium, l-alkyl-4-(2- diphenylphosphanylethyl)pyridinium, l-alkyl-3-(3-sulfopropyl- )imidazolium, and trialkyl-(3- sulfopropyl)phosphonium, and corresponding salts wherein at least one alkyl is substituted by alkoxyalkyl or alkyl thio alkyl.

29. The system of claim 28, wherein said alkoxyalkyl comprises methoxyethyl or ethoxyethyl.

30. The system of claim 28, wherein said alkylthio alkyl comprises methylthioethyl or ethylthioethyl.

31. The system of claim 1, wherein the storage liquid comprises an ionic liquid selected from the group consisting of:

1 -Ethyl-3-methylimidazolium bromide; 1 -Ethyl-3-methylimidazolium chloride; 1 -Butyl-3-methylimidazolium bromide; 1 -Butyl-3-methylimidazolium chloride; 1 -Hexyl-3-methylimidazolium bromide; 1 -Hexyl-3-methylimidazolium chloride; 1 -Methyl-3 -octylimidazolium bromide; 1 -Methyl-3 -octylimidazolium chloride; Monomethylamine hydrochloride; Trimethylamine hydrochloride; Tetraethylammonium chloride; Tetramethyl guanidine hydrochloride; N-Methylpyridinium chloride; N-Butyl-4-methylpyridinium bromide; N-Butyl-4-methylpyridinium chloride; Tetrabutylphosphonium chloride; and Tetrabutylphosphonium bromide.

32. The system of claim 1, wherein the chemical reagent comprises one of phosphine, pentaborane and arsine.

33. The system of claim 32, wherein the storage liquid comprises an anion component selected from among cuprate and aluminate, and a cation component derived from a dialkylimidazolium salt.

34. The system of claim 1, wherein the chemical reagent includes a reagent selected from the group consisting of phosphine, pentaborane, arsine, stibene, ammonia, hydrogen sulfide, hydrogen selenide, hydrogen telluride, organometallic compounds, and isotopically-enriched analogs thereof.

35. The system of claim 1, wherein the storage liquid comprises a Lewis basic anion.

36. The system of claim 35, wherein the Lewis basic anion is selected from the group consisting of carboxylates, 2-ethylhexanoate, fluorinated carboxylates, sulfonates, fluorinated sulfonates, imides, borates, sulfates, phosphates, chloride and partially protonated ions derived from polyprotic acids.

37. The system of claim 35, wherein the Lewis basic anion is selected from the group consisting of BF₄ ^", PF₆ ^", AsF₆ ^", SbF₆ ^", CH3COO\ CF3COO\ CF₃SO₃ ^", P-CH₃-C₆H₄SO₃ ^", (CF₃SOz)₂N^", (NC)₂N^", (CF₃SOz)₃C^", chloride, and F(HF)_n ^".

38. The system of claim 35, wherein the Lewis basic anion is selected from the group consisting of alkylaluminates, alkylborates and arylborates.

39. The system of claim 35, wherein the Lewis basic anion is selected from the group consisting of BF₄ ^", p-CH₃-C₆H₄SO₃ ^", CF₃SO₃ ^", (CF₃SO₂)₂N\ (NC)₂N-(CF₃SO₂)₃C\ CH₃COO^" and CF₃COO^".

40. The system of claim 35, wherein the Lewis basic anion is selected from the group consisting of R-O-SO₃ ^" (alkyl sulfates), wherein R is alkyl, ethyl sulfate; CH₃CH₂-O-SO₃ ^"; (RO)₂P(O)O^" (dialkylphosphate); and dibutylphosphate.

41. The system of claim 1, wherein the storage liquid comprises a Lewis basic cation.

42. The system of claim 41, wherein the Lewis basic cation is selected from the group consisting of cyclic moieties optionally including substituents selected from the group consisting of amine, phosphine, ether, carbonyl, nitrile, thioether, alcohol, and thiol.

43. The system of claim 1, wherein the chemical regent comprises a reagent selected from the group consisting of diborane, boron trifluoride, boron trichloride, SiF₄, germane, hydrogen cyanide, HF, HCl, Hl, HBr, GeF₄, alane, gallane, stibine, indane, organometallic compounds, and isotopically-enriched analogs thereof.

44. The system of claim 1, wherein the storage liquid comprises an ionic liquid halide.

45. The system of claim 44, wherein the chemical reagent comprises one of bromine in Br₃ ^" form, iodine in I₃ ^" or I₅ ^" or I₇ ^" form, and chlorine in ICl₄ ^" form.

46. The system of claim 1, wherein the storage liquid includes Lewis acid functional groups and/or Lewis base functional groups.

47. The system of claim 1, wherein the storage liquid is selected from the group consisting of tributylborane, tributyl borate, triethylaluminum, methanesulfonic acid, trifluoromethanesulfonic acid, titanium tetrachloride, tetraethyleneglycol dimethylether, trialkylphosphine, trialkylphosphine oxide, polytetramethyleneglycol, polyester, polycaprolactone, poly(olefin-alt-carbon monoxide), oligomers, polymers and copolymers of acrylates, methacrylates, and acrylonitrile.

48. The system of claim 1, wherein the storage liquid has solid particles therein that are adapted to prevent supersaturation of the storage liquid.

49. The system of claim 48, wherein the solid particles are selected from the group consisting of carbon particles, silica particles, ceramic honeycombs, silicon carbide particles and alumina particles.

50. The system of claim 1, further comprising a phase monitor arranged to monitor storage liquid in the reagent supply container to verify phase state thereof.

51. The system of claim 50, wherein the phase monitor comprises at least one impedance sensor arranged to sense impedance of the storage liquid.

52. The system of claim 50, wherein the phase monitor comprises an acoustic sensor.

53. The system of claim 1, wherein the storage liquid contains porous carbon beads.

54. The system of claim 1, as part of a microelectronic device manufacturing facility.

55. A method of chemical reagent delivery, comprising dissolving or dispersing a chemical reagent in a storage liquid to form a composition in which the chemical reagent is reversibly stored, applying ultrasonic energy to the composition to disengage the chemical reagent from the storage liquid in a volatilized form, and delivering the chemical reagent in the volatilized form to a locus of use of said chemical reagent.

56. The method of claim 55, wherein the storage liquid comprises an ionic liquid.

57. The method of claim 55, wherein the ultrasonic energy is generated by an ultrasonic nebulizer.

58. The method of claim 55, wherein the ultrasonic energy is generated by a piezoelectric ultrasonic nozzle.

59. The method of claim 55, wherein the chemical reagent includes a reagent species selected from the group consisting of photoresists, etching agents, organometallic compounds, dielectric materials, and dopants.

60. The method of claim 55, wherein the chemical reagent and storage liquid are in a reagent supply container containing an ultrasonic energy source at least partially disposed in an interior volume of the container.

61. The method of claim 55, wherein the chemical reagent and storage liquid are in a reagent supply container and the ultrasonic energy is generated by an ultrasonic energy source exterior of the container.

62. The method of claim 55, wherein the chemical reagent is fed to a microelectronic device manufacturing tool.

63. The method of claim 55, wherein the chemical reagent and storage liquid are in a reagent supply container, and the reagent supply container is unheated other than by the ultrasonic energy.

64. The method of claim 55, wherein the chemical reagent is fed to a vapor deposition chamber in which the chemical reagent is contacted with a substrate for deposition of a film-forming material thereon.

65. The method of claim 55, wherein the ultrasonic energy is generated by an ultrasonic vaporizer.

66. The method of claim 55, wherein the chemical reagent is delivered to the locus of use at sub -atmospheric pressure.

67. The method of claim 55, wherein the locus of use comprises a chamber that is maintained at sub-atmospheric pressure.

68. The method of claim 55, wherein the storage liquid comprises an ionic liquid.

69. The method of claim 55, wherein the storage liquid comprises a liquid selected from the group consisting of ionic liquids, mineral oils, silicon-based oils and fluorocarbon-based oils.

70. The method of claim 55, wherein the ultrasonic energy is generated by an ultrasonic vaporizer that adapted for on-off switched operation for pulsed dispensing of the chemical reagent for atomic layer deposition.

71. The method of claim 55, comprising conducting an atomic layer deposition with the chemical reagent at said locus of use.

72. A chemical reagent delivery method comprising providing a chemical reagent package including a vessel to which a dispensing assembly is coupled, wherein the vessel contains an ionic liquid in which the chemical reagent is stored, and from which it is disengaged and dispensed through the dispensing assembly under dispensing conditions involving ultrasonic energy impingement on the ionic liquid, and impinging ultrasonic energy on the ionic liquid to disengage the chemical reagent therefrom, and dispensing the disengaged chemical reagent through the dispensing assembly.

73. The method of claim 72, comprising generating said ultrasonic energy source within the vessel of the package.

74. The method of claim 72, comprising generating said ultrasonic energy source outside the vessel of the package.

75. The method of claim 72, comprising transferring the ionic liquid from the vessel to an ultrasonic energy impingement zone for impingement of ultrasonic energy thereon, to disengage the chemical reagent therefrom for dispensing thereof through the dispensing assembly.

76. The method of claim 55, wherein the storage liquid comprises a Lewis acid or Lewis base.

77. The method of claim 55, wherein the storage liquid comprises a reactive ionic liquid.

78. The method of claim 55, wherein the storage liquid comprises at least one of salts of alkylphosphonium, alkylammonium, N-alkylpyridinium and N,N'-dialkylimidazolium cations.

79. The method of claim 55, wherein the storage liquid comprises a liquid selected from among ethyl, butyl and hexyl derivatives of N-alkyl-N'-methylimidazolium and N-alkylpyridinium.

80. The method of claim 55, wherein the storage liquid comprises a cation selected from among pyridazinium, pyrimidinium, pyrazinium, pyrazolium, triazolium, thiazolium, oxazolium, ethylammonium and piperidinium.

81. The method of claim 55, wherein the storage liquid comprises an ionic liquid selected from the group consisting of salts of l-alkyl-3-(3-aminopropyl)imidazolium, l-alkyl-3-(3- ureidopropyl)- imidazolium, l-alkyl-3-(3-thioureidopropyl)imidazolium, l-alkyl-4-(2- diphenylphosphanylethyl)pyridinium, l-alkyl-3-(3-sulfopropyl- )imidazolium, and trialkyl-(3- sulfopropyl)phosphonium, and corresponding salts wherein at least one alkyl is substituted by alkoxyalkyl or alkyl thio alkyl.

82. The method of claim 81, wherein said alkoxyalkyl comprises methoxyethyl or ethoxyethyl.

83. The method of claim 81, wherein said alkylthio alkyl comprises methylthioethyl or ethylthioethyl.

84. The method of claim 55, wherein the storage liquid comprises an ionic liquid selected from the group consisting of:

1 -Ethyl-3-methylimidazolium bromide; 1 -Ethyl-3-methylimidazolium chloride; 1 -Butyl-3-methylimidazolium bromide; 1 -Butyl-3-methylimidazolium chloride; 1 -Hexyl-3-methylimidazolium bromide; 1 -Hexyl-3-methylimidazolium chloride; 1 -Methyl-3-octylimidazolium bromide; 1 -Methyl-3-octylimidazolium chloride; Monomethylamine hydrochloride; Trimethylamine hydrochloride; Tetraethylammonium chloride; Tetramethyl guanidine hydrochloride; N-Methylpyridinium chloride; N-Butyl-4-methylpyridinium bromide; N-Butyl-4-methylpyridinium chloride; Tetrabutylphosphonium chloride; and Tetrabutylphosphonium bromide.

85. The method of claim 55, wherein the chemical reagent comprises one of phosphine, pentaborane and arsine.

86. The method of claim 85, wherein the storage liquid comprises an anion component selected from among cuprate and aluminate, and a cation component derived from a dialkylimidazolium salt.

87. The method of claim 55, wherein the chemical reagent includes a reagent selected from the group consisting of phosphine, pentaborane, arsine, stibene, ammonia, hydrogen sulfide, hydrogen selenide, hydrogen telluride, organometallic compounds, and isotopically-enriched analogs thereof.

88. The method of claim 55, wherein the storage liquid comprises a Lewis basic anion.

89. The method of claim 88, wherein the Lewis basic anion is selected from the group consisting of carboxylates, 2-ethylhexanoate, fluorinated carboxylates, sulfonates, fluorinated sulfonates, imides, borates, sulfates, phosphates, chloride, and partially protonated ions derived from polyprotic acids.

90. The method of claim 88, wherein the Lewis basic anion is selected from the group consisting of BF₄ ^", PF₆ ^", AsF₆\ SbF₆\ CH3COO , CF3COO , CF₃SO₃ ^", P-CH₃-C₆H₄SO₃ ^", (CF₃SOz)₂N^", (NC)₂N^", (CF₃SOz)₃C^", chloride, and F(HF)_n ^".

91. The method of claim 88, wherein the Lewis basic anion is selected from the group consisting of alkylaluminates, alkylborates and arylborates.

92. The method of claim 88, wherein the Lewis basic anion is selected from the group consisting of BF₄ ^", p-CH₃-C₆H₄SO₃ ^", CF₃SO₃ ^", (CF₃SO₂)₂N\ (NC)₂N-(CF₃SO₂)₃C\ CH₃COO^" and CF₃COO^".

93. The method of claim 88, wherein the Lewis basic anion is selected from the group consisting of R-O-SO₃ ^" (alkyl sulfates), wherein R is alkyl, ethyl sulfate; CH₃CH₂-O-SO₃ ^"; (RO)₂P(O)O^" (dialkylphosphate); and dibutylphosphate.

94. The method of claim 55, wherein the storage liquid comprises a Lewis basic cation.

95. The method of claim 94, wherein the Lewis basic cation is selected from the group consisting of cyclic moieties optionally including substituents selected from the group consisting of amine, phosphine, ether, carbonyl, nitrile, thioether, alcohol, and thiol.

96. The method of claim 55, wherein the chemical regent comprises a reagent selected from the group consisting of diborane, boron trifluoride, boron trichloride, SiF₄, germane, hydrogen cyanide, HF, HCl, Hl, HBr, GeF₄, alane, gallane, stibine, indane, organometallic compounds, and isotopically-enriched analogs thereof.

97. The method of claim 55, wherein the storage liquid comprises an ionic liquid halide.

98. The method of claim 97, wherein the chemical reagent comprises one of bromine in Br₃ ^" form, iodine in I₃ ^" or I₅ ^" or I₇ ^" form, and chlorine in ICl₄ ^" form.

99. The method of claim 55, wherein the storage liquid includes Lewis acid functional groups and/or Lewis base functional groups.

100. The method of claim 55, wherein the storage liquid is selected from the group consisting of tributylborane, tributyl borate, triethylaluminum, methanesulfonic acid, trifluoromethanesulfonic acid, titanium tetrachloride, tetraethyleneglycol dimethylether, trialkylphosphine, trialkylphosphine oxide, polytetramethyleneglycol, polyester, polycaprolactone, poly(olefin-alt-carbon monoxide), oligomers, polymers and copolymers of acrylates, methacrylates, and acrylonitrile.

101. The method of claim 55, wherein the storage liquid has solid particles therein that are adapted to prevent supersaturation of the storage liquid.

102. The method of claim 101, wherein the solid particles are selected from the group consisting of carbon particles, silica particles, ceramic honeycombs, silicon carbide particles and alumina particles.

103. The method of claim 55, further comprising monitoring storage liquid in the reagent supply container to verify phase state thereof.

104. The method of claim 104, wherein the phase monitoring comprises sensing impedance of the storage liquid.

105. The method of claim 104, wherein the phase monitoring comprises acoustic sensing.

106 The method of claim 55, wherein the storage liquid contains porous carbon beads.

107. The method of claim 55, as part of a microelectronic device manufacturing process.

108. The system of claim 1, wherein the chemical reagent comprises a solid material.

109. The system of claim 1, wherein the chemical reagent comprises a liquid material.

110. The system of claim 19, wherein the chemical reagent comprises a solid material.

111. The system of claim 19, wherein the chemical reagent comprises a liquid material.

112. The method of claim 55, wherein the chemical reagent comprises a solid material.

113. The method of claim 55, wherein the chemical reagent comprises a liquid material.

114. The method of claim 72, wherein the chemical reagent comprises a solid material.

115. The method of claim 72, wherein the chemical reagent comprises a liquid material.

116. A system comprising a reagent supply container including a vessel holding a composition including a chemical reagent dissolved or dispersed in a storage liquid that is reversibly interactive with the chemical reagent to store the chemical reagent therein in a storage state, and to release the chemical reagent from the storage liquid for dispensing from the vessel of the reagent supply container in a dispensing state, wherein the storage liquid has solid particles therein that are adapted to prevent supersaturation of the storage liquid.

117. The system of claim 116, wherein the solid particles are selected from the group consisting of carbon particles, silica particles, ceramic honeycombs, silicon carbide particles and alumina particles.

118. The system of claim 116, further comprising a phase monitor arranged to monitor storage liquid in the reagent supply container to verify phase state thereof.

119. The system of claim 118, wherein the phase monitor comprises at least one impedance sensor arranged to sense impedance of the storage liquid.

120. The system of claim 118, wherein the phase monitor comprises an acoustic sensor.

121. The system of claim 116, wherein the storage liquid contains porous carbon beads.

122. The system of claim 116, as part of a microelectronic device manufacturing facility.

123. The system of claim 116, wherein the storage liquid comprises an ionic liquid.

124. A method of chemical reagent delivery, comprising dissolving or dispersing a chemical reagent in a storage liquid to form a composition in which the chemical reagent is reversibly stored in a storage mode of operation, releasing the chemical reagent from the storage liquid in a dispensing mode of operation, and delivering the released chemical reagent in a volatilized form to a locus of use of said chemical reagent, wherein the storage liquid has solid particles therein that are adapted to prevent supersaturation of the storage liquid.

125. The method of claim 124, wherein the solid particles are selected from the group consisting of carbon particles, silica particles, ceramic honeycombs, silicon carbide particles and alumina particles.

126. The method of claim 124, further comprising phase monitoring the storage liquid in the reagent supply container to verify phase state thereof.

127. The method of claim 126, wherein the phase monitoring comprises the use of at least one impedance sensor arranged to sense impedance of the storage liquid.

128. The method of claim 126, wherein the phase monitoring comprises use of an acoustic sensor.

129. The method of claim 124, wherein the storage liquid contains porous carbon beads.

130. The method of claim 124, as part of a process of microelectronic device manufacturing.

131. The method of claim 124, wherein the storage liquid comprises an ionic liquid.

132. A system comprising a reagent supply container including a vessel holding a composition including a chemical reagent dissolved or dispersed in a storage liquid that is reversibly interactive with the chemical reagent to store the chemical reagent therein in a storage state, and to release the chemical reagent from the storage liquid for dispensing from the vessel of the reagent supply container in a dispensing state, wherein the storage liquid has solid particles therein that are adapted to remove impurities from the storage liquid.

133. The system of claim 132, wherein the solid particles are selected from the group consisting of carbon particles, silica particles, ceramic honeycombs, silicon carbide particles and alumina particles.

134. The system of claim 132, wherein the solid particles comprise porous carbon beads.

135. The system of claim 132, as part of a microelectronic device manufacturing facility.

136. The system of claim 132, wherein the storage liquid comprises an ionic liquid.

137. A method of chemical reagent delivery, comprising dissolving or dispersing a chemical reagent in a storage liquid to form a composition in which the chemical reagent is reversibly stored in a storage mode of operation, releasing the chemical reagent from the storage liquid in a dispensing mode of operation, and delivering the released chemical reagent in a volatilized form to a locus of use of said chemical reagent, wherein the storage liquid has solid particles therein that are adapted to remove impurities from the storage liquid.

138. The method of claim 137, wherein the solid particles are selected from the group consisting of carbon particles, silica particles, ceramic honeycombs, silicon carbide particles and alumina particles.

139. The method of claim 137, wherein the storage liquid contains porous carbon beads.

140. The method of claim 137, as part of a process of microelectronic device manufacturing.

141. The method of claim 137, wherein the storage liquid comprises an ionic liquid.