Abstract: This invention is related to organometallic precursors and deposition processes for fabricating conformal metal containing films on substrates such as silicon, metal nitrides and other metal layers. The organometallic precursors are N,N?-alkyl-1,1-alkylsilylamino metal complexes represented by the formula: wherein M is a metal selected from Group VIIb, VIII, IX and X, and specific examples include cobalt, iron, nickel, manganese, ruthenium, zinc, copper, palladium, platinum, iridium, rhenium, osmium, and the R1-5 can be same or different selected from hydrogen, alkyl, alkoxy, fluoroalkyl and alkoxy, cycloaliphatic, and aryl.

Abstract: Carbon nanotubes are formed on carbon paper by first depositing a metal catalyst on the carbon paper, and passing a feedstock gas containing a source of carbon over the substrate while applying an electrical current thereto to heat the substrate sufficiently to generate a reaction between the catalyst and the feedstock gas. Alternatively, inert gas under pressure is passed through a tubular metal cathode while passing an electric current through the cathode to produce a plasma of fine catalyst particles which are deposited on a porous carbon substrate, and a feedstock gas containing a source of carbon is passed over the substrate to cause a reaction between the catalyst and the carbon source resulting in the formation of carbon nanotubes.

Abstract: A method of coloring cut gemstones introduces metals or metal oxides into a surface layer by means of heat treatment. During the heat treatment the gemstones are laid on a solid plate and the metals or metal oxides form a substantial constituent of the plate. The surface of the gemstone is protected from direct content with the metals and metal oxides in the plate by a layer containing non-coloring oxides.

Abstract: A single source precursor for depositing ternary I-III-VI2 chalcopyrite materials useful as semiconductors. The single source precursor has the I-III-VI2 stoichiometry “built into” a single precursor molecular structure which degrades on heating or pyrolysis to yield the desired I-III-VI2 ternary chalcopyrite. The single source precursors effectively degrade to yield the ternary chalcopyrite at low temperature, e.g. below 500° C., and are useful to deposit thin film ternary chalcopyrite layers via a spray CVD technique. The ternary single source precursors according to the invention can be used to provide nanocrystallite structures useful as quantum dots. A method of making the ternary single source precursors is also provided.

Abstract: A volatile copper aminoalkoxide complex of formula (I) can form a copper thin film having an improved quality by metal organic chemical vapor deposition (MOCVD): wherein, R1, R2, R3 and R4 are each independently C1-4 alkyl optionally carrying one or more fluorine substituents; and m is an integer in the range of 1 to 3.

Abstract: Disclosed are methods of preparing monoalkyl Group VA metal dihalide compounds in high yield and high purity by the reaction of a Group VA metal trihalide with an organo lithium reagent or a compound of the formula RnM1X3?n, where R is an alkyl, M1 is a Group IIIA metal, X is a halogen and n is an integer fro 1 to 3. Such monoalkyl Group VA metal dihalide compounds are substantially free of oxygenated impurities, ethereal solvents and metallic impurities. Monoalkyl Group VA metal dihydride compounds can be easily produced in high yield and high purity by reducing such monoalkyl Group VA metal dihalide compounds.

Abstract: A method includes forming an as-grown film of a superconductor composed of a MgB2 compound which is made by simultaneous evaporation of magnesium and boron. The as-grown film is superconductive without an annealing process to make the film superconductive. The method can be applied to fabricate an integrated circuit of the superconductor film, because a high temperature annealing process to make the as-grown film superconductive is not needed.

Abstract: Asymmetric, disubstituted metallocene compounds have the general formula CpMCp? where M is a metal selected from the group consisting of Ru, Os and Fe; Cp is a first substituted cyclopentadienyl or indenyl moiety that includes at least one substituent group D1; Cp? is a second substituted cyclopentadienyl or indenyl moiety that includes at least one substituent group D1?. D1 is different from D1?.

Abstract: A composite surface having a thickness from 10 to 5,000 microns comprising a spinel of the formula MnxCr3?xO4 wherein x is from 0.5 to 2 and oxides of Mn, Si selected from the group consisting of MnO, MnSiO3, Mn2SiO4 and mixtures thereof which are not prone to coking and are suitable for hydrocarbyl reactions such as furnace tubes for cracking.

Abstract: A method for producing Group 8 (VIII) metallocene or metallocene-like compounds employs a compound that includes a Cp? anion, such as found, together with a counterion, in a cyclopentadienide or cyclopentadienide-like salt. In one embodiment, the method includes reacting a metal salt, a (Cp) compound, such as a substituted or unsubstituted cyclopentadiene or indene, and a ligand (L) to form an intermediate compound and reacting the intermediate compound with a Cp? compound, eg., a cyclopentadienide or cyclopentadienide-like salt, where the metal salt can be is a ruthenium, an osmium or an iron halide or nitrate and L is an electron pair donor. Unsubstituted, mono-substituted as well as symmetrically or asymmetrically di- or multi-substituted metallocenes or metallocene-like compounds can be produced. In another embodiment, unsubstituted or symmetrically substituted metallocenes are formed by reacting MX2(PPh3)m with a Cp? compound, where m=3 or 4.

Abstract: Nitroxide mediated free radical polymerization of vaporized vinyl monomers, including acrylic acid (AAc), styrene (St), N-2-(hydroxypropyl)methacrylamide (HPMA) and N-isopropyl acrylamide (NIPAAm), on silicon wafers is demonstrated. FTIR, ellipsometry and contact angle goniometry were used to characterize the chemical structures, thickness and hydrophilicity of the films. The growth of film is linearly proportional to its reaction time, leading to the easy and exact control of polymer film thickness from nanometers to submicrons. The capability of polymerizing various monomers allows us to fabricate various functional polymer brushes. The reversible thermo-responsiveness of a 200 nm thick grafted poly(NIPAAm) film in aqueous solution is demonstrated with over 50% change in thickness at its lower critical solution temperature. A tri-block copolymer of poly(AAc)-b-polySt-b-poly(HPMA) is successfully synthesized, proving the renewability of TEMPO-mediated polymerization at vapor phase.

Abstract: This invention provides a process of preparing dihydrocarbylamido metal compounds. This process comprises bringing together, in a liquid reaction medium, at least one metal halide, MX4, where M is titanium, zirconium, or hafnium, and X is a halogen atom, with at least one dihydrocarbylamine, such that a mixture of (i) halometal amides in which the atom ratio of halogen to metal is greater than about 0.1 and less than about 2, and (ii) dihydrocarbylamine hydrohalide is produced. Then (i) and (ii) are separated from each other, and (i) is brought together with an alkali metal amide, ANR2, where A is an alkali metal, and R is a hydrocarbyl group, in a liquid medium, to produce a product comprised of substantially halogen-free dihydrocarbylamido metal compound. This invention further provides for purifying dihydrocarbylamido metal compounds by contact with a nitrile.

Abstract: The present invention is a method for recycling an organometallic compound for MOCVD comprising extracting an unreacted organometallic compound from a used raw material which has undergone a thin film production process, wherein the unreacted organometallic compound is extracted after the used raw material is subjected to a reforming treatment. The method for reforming the used raw material is either a method for contacting the used raw material with a hydrogenation catalyst or a reducing agent or a method for contacting the used raw material with either a halogen, a hydrogen halide, an inorganic acid, an alkene, or a diene. In this case, an organometallic compound of higher purity can be obtained through this recycling method by contacting the used raw material with a decoloring agent comprising activated carbon, silica, or activated clay.

Abstract: Copper precursors of the formula (I): wherein: Cu is Cu(I) or Cu(II); x is an integer having a value of from 0 to 4; each of R, R′ and R″ may be the same as or different from one another and each is independently selected from the group consisting of H, C1-C6 alky), C1-C6 perfluoroalkyl and C6-C10 aryl; when Cu is Cu(I), A is a Lewis base; when Cu is Cu(II), A is: wherein x, R, R′ and R″ are as specified above.

Abstract: This invention is directed to a group of novel homologous eight membered ring compounds having a metal, such as copper, reversibly bound in the ring and containing carbon, nitrogen, silicon and/or other metals. A structural representation of the compounds of this invention is shown below: wherein M and M′ are each a metal such as Cu, Ag, Au and Ir; X and X′ can be N or O; Y and Y′ can be Si, C; Sn, Ge, Al, or B; and Z and Z′ can be C, N, or O. Substituents represented by R1, R2, R3, R4, R5, R6, R1′, R2′, R3′, R4′, R5′, and R6′ will vary depending on the ring atom to which they are attached. This invention is also directed to depositing metal and metal-containing films on a substrate, under ALD or CVD conditions, using the above novel compounds as precursors.

Abstract: A process for producing thin layers in electronic devices such as integrated circuit chips, is provided. The process includes the steps of injecting a precursor fluid into a thermal processing chamber containing a substrate, such as a semiconductor wafer. The precursor fluid is converted into a solid which forms a layer on the substrate. In accordance with the present invention, the precursor fluid is pulsed into the process chamber in a manner such that the fluid is completly exhausted or removed from the chamber in between each pulse. Light energy can be used in forming the solid layers.

Abstract: Thin films of conducting and superconducting materials are formed by a process which combines physical vapor deposition with chemical vapor deposition. Embodiments include forming boride films, such as magnesium diboride, in high purity with superconducting properties on substrates typically used in the semiconductor industry by physically generating magnesium vapor in a deposition chamber and introducing a boron containing precursor into the chamber which combines with the magnesium vapor to form a thin boride film on the substrate.

Abstract: Disclosed are organometallic compounds derived from Groups VIIb, VIII, IX, and X metals useful as precursors for the formation of metal containing powders and for the chemical deposition of the metals on substrates, particularly for the chemical vapor deposition of metal films suitable for the manufacture of electronic devices. Methods for their use are also disclosed.

Abstract: A volatile solid-source novel antimony precursor, Br2SbCH3, that may be utilized in semiconductor processing chambers for depositing antimony on a substrate by deposition methods, e.g., chemical vapor deposition, ion implantation, molecular beam epitaxy, diffusion and rapid thermal processing. The novel antimony compound of the invention is synthesized by combining tribromide antimony with trimethylantimony under heating conditions that form a Br2SbCH3 crystalline product.

Abstract: The present invention relates to a raw material for CVD comprising an organic iridium compound as a main component, said organic iridium compound being tris(2,4-octanedionato)iridium represented by Formula 1. Particularly preferably, the raw material for CVD consists only of the trans isomer of tris(2,4-octanedionato)iridium.

Abstract: A process of producing a strontium titanate, barium titanate or barium strontium titanate thin film by chemical vapor deposition which comprises using a titanium compound represented by formula (I): wherein R1 represents a hydrogen atom or a methyl group; and R2 and R3 each represent a methyl group or an ethyl group, or R2 and R3 are connected together to form a methylene group, a methylmethylene group or a dimethylmethylene group.

Abstract: This invention provides raw material compounds for use in CVD which contain organic ruthenium compounds as a main ingredient, the organic ruthenium compounds having two &bgr;-diketones plus one diene, one diamine or two organic ligands which are coordinated with ruthenium. In this invention, the vapor pressures of the organic ruthenium compounds are made preferable by specifying the number of the carbon atoms contained in the above &bgr;-diketones and the types of the above diene etc.

Abstract: A method of forming polycrystalline silicon for a liquid crystal display device is disclosed in the present invention. The method includes forming an amorphous silicon layer on a substrate, forming a plurality of catalytic metal clusters on the amorphous silicon layer, forming a catalytic metal gettering layer adjacent to the amorphous silicon layer, and heat-treating the substrate including the amorphous silicon layer to transform the amorphous silicon layer into a polycrystalline silicon layer, wherein unreacted catalytic metal clusters migrate to the catalytic metal gettering layer in a direction perpendicular to the substrate.

Abstract: A compound of formula (I) wherein X is aluminium, gallium or indium; each Y, which may be the same or different, is nitrogen or phosphorus; R1 and R2, which may be the same or different, are hydrogen, halogen or alkyl; and R3 to R7, which may be the same or different, are hydrogen or a saturated group, or R3 and R4, or R5 and R6 together represent a saturated divalent link thus completing a ring.

Abstract: Disclosed are trialkylindium compounds containing two bulky alkyl groups that are liquids or easily liquefiable solids and have sufficient vapor pressure for use in vapor deposition processes, as well as methods of depositing indium containing films using such compounds.

Abstract: This invention provides raw material compounds for use in CVD which contain an organic iridium compound as a main ingredient, the organic iridium compound consisting of tris(5-methyl-2,4-hexanedionato)iridium. According to the CVD which uses the above raw material compounds, a pure iridium thin film and an iridium oxide thin film of excellent morphology can be produced effectively.

Abstract: A &bgr;-diketonatocopper(I) complex which contains as a ligand (L) an allene compound and is represented by formula (2) wherein, R6 and R7 may be the same or different and each represents linear or branched C1-4 alkyl, C1-4 alkoxy, or linear or branched C1-4 fluoroalkyl, R8 represents hydrogen or fluorine, and L represents the allene compound, and a process for producing the same. The complex is useful in forming a thin copper film by metal-organic vapor deposition (hereinafter abbreviated as MOCVD) method.

Abstract: A thin film deposition method uses a vacuum confinement cup that employs a dense hot filament and multiple gas inlets. At least one reactant gas is introduced into the confinement cup both near and spaced apart from the heated filament. An electrode inside the confinement cup is used to generate plasma for film deposition. The method is used to deposit advanced thin films (such as silicon based thin films) at a high quality and at a high deposition rate.

Abstract: Nitrogen containing analogs of Copper II &bgr;-diketonates which analogs are more stable source reagents for copper deposition when substantially free of solvents of excess ligands. The nitrogen containing analogs replace —O— with —N(R″)— wherein R″ is an alkyl group having from one to four carbon atoms. Replacement of each —O— is preferred although replacement of one —O— per cyclic ring is sufficient to improve stability of the copper source reagents. The source reagent can be purified by sublimation to remove solvents and excess ligands prior to semiconductor processing.

Abstract: The present invention is a method for recycling an organometallic compound for MOCVD comprising extracting an unreacted organometallic compound from a used raw material which has undergone a thin film production process, wherein the unreacted organometallic compound is extracted after the used raw material is subjected to a reforming treatment. The method for reforming the used raw material is either a method for contacting the used raw material with a hydrogenation catalyst or a reducing agent or a method for contacting the used raw material with either a halogen, a hydrogen halide, an inorganic acid, an alkene, or a diene. In this case, an organometallic compound of higher purity can be obtained through this recycling method by contacting the used raw material with a decoloring agent comprising activated carbon, silica, or activated clay.

Abstract: The present invention provides for a method to reduce the strength of the honeycomb of a jet turbine stator, increasing its machinability, with a resultant reduction in measured peak tooth temperature, while maintaining or even improving its high temperature capability, so as not to limit its operating environment. The air seal functionality is unaffected, and even improved in some instances. The machinability of the honeycomb is increased by using a light element diffused into the honeycomb ribbon to produce the effect of reducing its strength and ductility while maintaining the environmental resistance needed. The present invention also includes the stator honeycomb produced by the foregoing method.

Abstract: A ruthenium-containing thin film is produced by the chemical vapor deposition method etc. with the use of an organometallic ruthenium compound represented by the general formula (1), specific example of which is (2,4-dimethyl-pentadienyl)(ethylcyclopentadienyl)ruthenium: or an organometallic ruthenium compound represented by the general formula (7), specific example of which is carbonylbis(2-methyl-1,3-pentadiene)ruthenium: as the precursor.

Abstract: The invention comprises an organotitanium precursor formed from a &bgr;-ketoester and a titanium glycolate, and dimer precursors formed from a reaction of the above organotitanium precursor with alcohol, which are used as sources of titanium dioxide for metal-organic chemical vapor deposition (MOCVD).

Abstract: Single imido tungsten imido precursors are described for the deposition of tungsten nitride on a substrate by processes such as metal organic chemical vapor deposition. The precursors may be employed to form diffusion barrier layers on microelectronic devices. A method for forming tungsten nitride layers includes the steps of providing a tungsten imido species having the formula LyW(NR)Xn, where R is a carbon containing group, y is an integer between 0 and 5, n is an integer between 0 and 4 and Ly and Xn are selected from the group of non-imido ligands. The single imido tungsten imido species is flowed to a surface of a substrate where the single imido tungsten imido species decomposes to form a tungsten nitride layer.

Abstract: The present invention provides a process for producing cyclopentadiene or a derivative thereof by heating a mixture containing at least one of dicyclopentadiene or a derivative thereof, the process comprising: a first step comprising heating the mixture into vapor; a second step comprising maintaining while heating the vapor at a temperature higher than the boiling point of the desired cyclopentadiene or derivative thereof to condense and remove high-boiling components and simultaneously collect residual vapor; and a third step comprising maintaining while heating the collected vapor at a temperature lower than the boiling point of the desired cyclopentadiene or derivative thereof to condense and collect the cyclopentadiene or derivative thereof. In the third step, the vapor may be contact with nitrogen gas to improve the yield of the cyclopentadiene or derivative thereof.

Abstract: Within a chamber in a vacuum atmosphere, SiO is deposited on a glass substrate so as to form a first layer as a protective film, Al is deposited on the first layer so as to form a second layer as an aluminum reflective film, MgF2 is deposited on the second layer so as to form a third layer as a transparent protective film, and CeO2 is deposited on the third layer so as to form a fourth layer as a transparent protective film. Then, while O2 gas is introduced into the chamber, SiO2 is deposited on the fourth layer so as to form a fifth layer as a transparent protective film.

Abstract: The invention relates to a process for preparing niobium(V) alkoxides and tantalum(V) alkoxides, in particular niobium(V) ethoxide and tantalum(V) ethoxide, by reacting NbCl5 or TaCl5 with an appropriate alcohol in the presence of ammonia, wherein NbCl5 or TaCl5 is dissolved at a temperature of from about 0° C. to −50° C. in the alcohol containing from about 5 to about 7 mol of ammonia per mol of NbCl5 or TaCl5 to be reacted.

Abstract: A hard carbon thin film formed on a substrate has a graded structure in which a ratio of sp2 to sp3 carbon-carbon bonding in the thin film decreases in its thickness direction from a thin film/substrate interface toward a surface of the thin film. A method of forming the thin film involves varying the film-forming ion species over time to produce the composition gradient or structural gradient in the thickness direction of the thin film.

Abstract: A process for forming a coating on a substrate by condensation of a coating material onto the substrate while the substrate is moving through an enclosure under vacuum in which evaporation of the coating material takes place. With the inventive process, deposits with controlled structure and adhesion can be made on moving substrate or support even at very high speeds, so that the process can advantageously be carried out continuously or at variable speed.

Abstract: A hot wire chemical vapor deposition method and apparatus for fabricating high quality amorphous, micro-crystalline, and poly-crystalline thin film silicon, or related materials, devices and large area modules is described. A silane gas impinges upon a hot graphite rod assembly whereas the gas is broken up into its individual constituents, these constituents then depositing on an inert substrate member. The distance between the hot graphite rod assembly and the substrate member is adjustable. A shutter is provided to shield the substrate member as the hot graphite rod assembly is heating up. The hot graphite rod assembly contains a plurality of mutually parallel and coplanar rods that are parallel to the plane of the substrate member, and the hot graphite rod assembly and/or the substrate is oscillated in a direction generally normal to the direction in which the rods extend.

Abstract: A first organometallic compound is an organometallic compound for manufacturing a ruthenium film or a ruthenium compound film by a chemical vapor deposition process, wherein the organometallic compound is alkylcyclopentadienyl(cyclopentadienyl)ruthenium having a substituent of n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group. A second organometallic compound is an organometallic compound for manufacturing an iridium film or an iridium oxide film by a chemical vapor deposition process, wherein the organometallic compound for chemical vapor deposition is alkylcyclopentadienyl(1,5-cyclooctadiene)iridium having a substituent of any alkyl group of n-propyl group, iso-propyl group, or n-butyl group, iso-butyl group, tert-butyl group.

Abstract: Volatile low melting solid Cu(II) metal complexes are provided which are capable of depositing a copper film on various substrates under CVD conditions in the absence of reducing carrier gas H2. These CU(II) metal complexes are represented by the structure formula: Cu(OCCF3R1CH2NHR2)2 wherein R1 is selected from hydrogen, C1-C4 lower-alkyl or perfluorinated C1-C4 lower-alkyl groups, e.g., CH3, and CF3, etc., and wherein R2 is C1-C6 lower-alkyl or C1-C6 lower-alkene, which may be substituted by one or more fluorine atoms, by a C1-C6 lower-alkoxy group or by a C1-C6 di-lower-alkyl amino group, provided that when R1 is CF3, R2 is other than hydrogen or methyl. A process for depositing copper film using these Cu(II) metal complexes is also provided.

Abstract: A process for the continuous production of coated metallic bands obtained by physical phase vapor deposition includes the following steps carried out on a band, eventually coated with zinc or its alloys, in motion and maintained in a vacuum environment: heating the band to be coated; activating the band surface; heat stabilizing the band; depositing a zinc layer on the metallic band; secondary heat stabilizing the band; and depositing one or more elements or compounds on the zinc layer, these elements being able to synergistically interact with the zinc layer to obtain high corrosion resistance, weldability, ductility, and adhesion.

Abstract: In a pigment depositing device for forming a recording layer of an optical recording medium, there is used an organic pigment of powder state, in which the diameter of each of particles of the organic pigment is uniform. In consequence, occurrence of splash is prevented when the organic pigment is heated by an electrical heater so that it is prevented that the particles of the organic pigment adhere to a substrate. Moreover, fluidity of the organic pigment in an organic pigment feeding device is raised so that the organic pigment is smoothly fed.

Abstract: A method and apparatus for nucleation and growth of diamond by hot-filament DC plasma deposition. The apparatus uses a resistively heated filament array for dissociating hydrogen in the reactant gas. For two sided diamond growth, configurations of substrate-hot filament-grid-hot filament-substrate or substrate-hot filament-hot filament-substrate configuration are used. For the latter configuration, two independent arrays of filaments serve as both hot filament and grid, and AC or DC plasma is maintained between the filament arrays. For this and the other electrode configurations, the grid electrode is positively biased with respect to the hot filaments to maintain a plasma. The plasma potential gradient across the grid and the hot-filament draws ions from the plasma towards the filaments. To further increase deposition rates, the filament array is biased negatively with respect to the substrate holder so that a DC plasma is also maintained between the substrate and filament array.

Abstract: A process for forming a metal oxide film by means of a chemical vapor deposition system, which comprises using a complex of a .beta.-diketone compound and a group IV metal glycolate, the complex being represented by formula (I): ##STR1## wherein M represents a metal atom of the group IV; R.sup.1 and R.sup.2 each represent a branched alkyl or cycloalkyl group having 4 to 8 carbon atoms; and R.sup.3 represents a straight-chain or branched alkylene group having 2 to 18 carbon atoms.

Abstract: Enhanced adhesion between a vapor deposited metal and an organic polymer surface is achieved without utilizing any intermediate surface preparatory steps. The morphology of the polymer surface is tailored to produce mounds and dimples on the surface which leads to a mechanically tougher, interdigitated metal/polymer interface. In the preferred embodiment, a solution of a solvent or solvent system and two or more polymer precursors or polymers or combinations thereof are cast in a film on a substrate and heated to spontaneously form a rough surface due to phase separation. The surface topography of such a film consists of characteristic mounds and dimples depending upon the composition of the solution. Direct metal vapor deposition onto the roughened surface results in an enhanced adhesion of the metal to the organic polymer surface. The organic polymer surface or substrate may be, but need not be, attached to yet another underlying substrate such as a ceramic (e.g.

Abstract: The film-forming apparatus includes a gas introduction tube for introducing an inert gas into a vacuum chamber, a vapour source and a target, and forms a thin film by depositing sputtered particles and evaporated particles on the surface of a substrate, the sputtered particles being liberated by sputtering the target using ion energy of plasma generated around the target while the evaporated particles being obtained by evaporating a vapour source by heating and ionising evaporated components using the plasma.

Abstract: The invention relates to a flash TV evaporator for the evaporation coating of cathode ray tubes with aluminium, having a cavity from which the aluminium is evaporated when a current flows through the flash TV evaporator, wherein the width of the cavity tapers from the upper edge of the evaporator to the lower edge of the evaporator.

Abstract: A Cu(hfac) precursor with a substituted ethylene ligand has been provided. The substituted ethylene ligand includes bonds to molecules selected from the group consisting of C.sub.1 to C.sub.8 alkyl, C.sub.1 to C.sub.8 haloalkyl, H, and C.sub.1 to C.sub.8 alkoxyl. One variation, the 2-methyl-1-butene ligand precursor has proved to be stable at room temperature, and extremely volatile at higher temperatures. Copper deposited with this precursor has low resistivity and high adhesive characteristics. Because of the volatility, the deposition rate of copper deposited with this precursor is very high. A synthesis method has been provided which produces a high yield of the above-described precursor.