Showing papers on "Sodium hypophosphite published in 1998"

Method of forming electric pad of semiconductor device and method of forming solder bump

Abstract: Electroless nickel plating and gold plating is performed on an aluminum electrode in order to construct a highly reliable electrode. The steps are: depositing zinc on the aluminum electrode with zincate treatment liquid containing sodium hydroxide and zinc oxide; immersing it in solution which is prepared by dissolving sodium hypophosphite as a reducing agent into de-ionized water, followed by addition of de-ionized water while adjusting for the pH of 9.0 to 12.0 with sodium hydroxide solution, so as to make a total volume of 1000 ml; nickel-plating the aluminum electrode of the semiconductor device by using electroless nickel plating solution of oxidation-reduction reacting type containing sulfur compound as a reaction promoter, under a condition of the pH at 4.0 to 6.8 and a temperature of 80 to 90° C.; electroless gold-plating by substitutional reaction type; and, electroless gold-plating by oxidation-reduction reacting type, so as to form a nickel film containing phosphor and gold plated films on all aluminum electrodes of the semiconductor device. In this way, a nickel plate film of good electrical conductivity and also a gold plate of a thick film on all aluminum electrodes of the semiconductor device are formed, without resulting in corrosion of the passivation film and the aluminum electrodes.

Diffusion barrier properties of electroless Ni for electroless Cu using Cu plating employing hypophosphite as a reducing agent

Abstract: A series of experiments have been conducted into the feasibility of a copper interconnection manufacturing scheme in which a nickel layer is employed as the patterning guide and the cushion to subsequent electroless copper deposition. It was found that with nickel as mediator and sodium hypophosphite as the reducing agent, the copper layer can be selectively deposited on Si wafers by an electroless plating process, which saves the conventional dry etching process to pattern the copper layer. Diagnostics on such copper interconnections, using Auger electron spectroscopy (AES), cross-sectional transmission electron microscopy (XTEM) and energy dispersive spectroscopy (EDS), all indicated no diffusion of the deposited copper into the underlying nickel layer after going through 350 °C, one hour heat treatment. © 1998 Kluwer Academic Publishers

Method for forming electrode of semiconductor element

Abstract: PROBLEM TO BE SOLVED: To provide electroless nickel plating and gold plating methods on an aluminum electrode for forming a highly reliable electrode. SOLUTION: Zinc is deposited 14 on the aluminum electrode 12 with zincate treating liquid containing sodium hydroxide and zinc oxide. Then, sodium hypophosphite being a reducing agent is dissolved in pure water. Pure water is added while it is adjusted to pH 9.0-12.0 with sodium hydroxide solution and it is immersed into solution 15 which is set to be 1000 mL in total. Then, nickel plating is executed with the condition of pH 4.0-6.8 at 80-90°C by using oxidation-reduction reaction electroless nickel plating liquid containing sulfur compound with the aluminum electrode 12 of the semiconductor element as reaction accelerator. Thus, a nickel film 16 containing phosphorus and gold plating films 17 and 18 are obtained in all the aluminum electrodes 12 of the semiconductor element by executing substitution reaction electroless gold plating and oxidation reduction-type electroless plating. COPYRIGHT: (C)1999,JPO

Self-catalytic bath and method for the deposition of a nickel-phosphorus alloy on a substrate

Abstract: Disclosed are a self-catalytic bath and a method for the deposition of Ni-P alloy on a substrate. The bath comprises nickel sulfate, sodium hypophosphite as a reducing agent, acetic acid as a buffer and traces of lead as a stabilizer. It also includes a citrate used as a complexing agent associated with a gluconate used both as a catalyst and a stabilizer. The disclosed bath makes it possible to tolerate large quantities of hypophosphite and is relatively long-lived. Furthermore, it can be used to prepare large quantities of Ni-P alloy per liter of solution.

FORMING METHOD OF ELECTROLESS Ni-P PLATING LAYER ON GLASS SUBSTRATE FOR MAGNETIC DISK

Abstract: PROBLEM TO BE SOLVED: To omit a polishing process before a texturing process by successively subjecting the surface of a glass substrate to degreasing treatment, etching treatment, treatment with warm pure water, treatment with a silane coupling agent, activator treatment and accelerator treatment, and then subjecting to electroless Ni-P plating and to heat treating. SOLUTION: The surface of a glass substrate is subjected to alkali degreasing treatment to remove contaminants and to acid etching to remove remaining oxide films. The purified glass substrate surface is treated with warm pure water at about >=90 deg.C to newly form an oxide film, and then treated with, for example, an amino-based silane coupling agent. Then the surface is subjected to activation (activator treatment) with, for example, a palladium chloride aq. soln., further subjected to reaction acceleration treatment (accelerator treatment) with, for example, a sodium hypophosphite aq. soln., then subjected to electroless Ni-P plating to form a Ni-P plating layer, and then subjected to specified heat treatment.

Oxidation of sodium hypophosphite by alcohol on metallic palladium

Abstract: Sodium hypophosphite NaH 2 PO 2 is rapidly oxidized by MeOH or BuOH in the presence of palladium at 50-80°C to form sodium monoalkylphosphite (RO)(NaO)HPO and H 2 , Kinetics and mechanism of the reaction were studied by the volumetric method, redox potentiometry, 31 P NMR spectroscopy, and gas-liquid chromatography. Optimal conditions of a new reaction were found. It was shown that the reaction occurs on the palladium surface at stationary hydrogen potential that depends on the pH of the medium. The reaction occurs via the following steps: (i) the isomerization of phosphoryl form of hypophosphite (NaO)H 2 PO to hydroxide (NaO)(HO)HP, (ii) the dissociation of a P-H bond of hypophosphite and O-H bond of alcohol, (iii) the adsorption of H-atoms, phosphonyl (NaO)(HO)P, and alkoxy RO radicals, (iv) the recombination of hydrogen atoms, and (v) P-O-coupling of phosphonyl and alkoyl radicals to yield H 2 and sodium monoalkylphosphite (RO)(NaO)HPO. The kinetic and activation parameters of sodium hypophosphite oxidation by alcohols are presented.

Method of making flue gas harmless

Abstract: Formation of dioxins in flue gases is inhibited by contacting the flue gas with at least one of sodium phosphite, calcium phosphate, sodium hypophosphite, and calcium as reducing agents preferably at a temperature in the range of from 150° C. to 850° C. Hydrogen chlorides are also rendered harmless by the contact with the reducing agent. Also, metal ions contained in the fly ash of the flue gas are reduced to metals to reduce the occurrence of dissolution of the metals in subsequent treatment of the fly ash.

Electroless nickel plating liquid and electroless nickel plating method

Abstract: PROBLEM TO BE SOLVED: To obtain an electroless nickel plating method which imparts a smooth Ni-P film to an Al substrate for hard disks by immersing the substrate into a plating liquid which contains nickel ions, their complexing agents and hypophosphorous acid ions and is added with water-soluble sulfur based additives and water-soluble molybdate and/or tungstate in combination. SOLUTION: The sulfur based additives are one or >=2 kinds selected from thiosulfate (sodium thiosulfate, potassium thiosulfate, etc.), thiocyanate (sodium thiocyanate, potassium thiocyanate, etc.), thiourea and thioacetate. The example of the supply source of the nickel ions includes a water-soluble nickel salt, such as nickel sulfate. One or >=2 kinds of monocarboxylic acid, dicarboxylic acid, tricarboxylic acid and carboxylic acids are used in combination as the complexing agents of the nickel ions. The hypophosphorous acid ions are supplied by sodium hypophosphite, etc. The plating liquid is adequately used for the Al substrate for the hard disks by immersing the substrate into the plating liquid after a zinc substitution treatment.

Hypophosphite deoxygenation reactions in the synthesis of erythromycin derivatives

Abstract: A process for the preparation of 4"-deoxyerythromycins, having the formula: ##STR1## wherein R is H or OH, R 1 is H or loweralkyl, and R 2 is H or CH 3 by treatment of the starting material, 2'-O-acetyl-4"-imidazolylthiocarbamoyl-erythromycin, with a hypophosphite reagent, in a water-miscible protic solvent optionally comprising a phase transfer agent. In a preferred embodiment, the water-miscible solvent is an alcohol and the starting material is reacted with sodium hypophosphite, ACVA and tetra-n-butylammonium hydroxide.

Process for producing hypophosphite compounds

Abstract: Methods for the production of nickel or ammonium hypophosphite are disclosed, including combining sodium hypophosphite with nickel or ammonium sulfate to produce sodium sulfate and nickel or ammonium hypophosphite, and lowering the temperature of the solution containing the sodium sulfate to crystallize out the sodium sulfate.

Electroless nickel plating solution

Abstract: PROBLEM TO BE SOLVED: To obtain an electroless nickel plating soln. from which sulfates are not formed and accumulated in plating by mixing the the hydrous nickel hypophosphite as the main chemical for supplying Ni ion and H2 PO2 ion and the hypophosphorous acid, etc., as a molar ratio regulator to prepare the plating soln. SOLUTION: A plating soln. contg. hydrous nickel hypophosphite (nickel hypophosphite hexahydrate is preferable) as the main chemical for supplying metallic ion Ni and hypophosphite ion H2 PO2 as a reducing agent and hypophosphorous acid and/or sodium hypophosphite as the molar ration regulator is prepared. At this time, the plating soln. contains 0.017-0.34mol/l Ni and 0.017-10mol/l H2 PO2 in the stationary state, the molar ratio of H2 PO2 to Ni is controlled to 2.5-4, and the pH is regulated to 4.5-5.5 in an acid bath and to 9-10 in the alkali bath. An electroless nickel plating soln. having a long service life, with the exhausted plating soln. easily discarded and capable of being regenerated and utilized is obtained in this way.

Spherical amorphous co(cobalt)-ni-p ternary alloy powder and its production

Abstract: PROBLEM TO BE SOLVED: To obtain a Co-Ni amorphous alloy by liq. phase reduction by compos ing it of spherical particles in which the average particle size is regulated to specified value or below. SOLUTION: By a liq phase reducing method, spherical amorphous Co-Ni-P ternary allow powder having η3 μm average particle size can be obtd. This liq. phase reduction is executed concretely as follows: an aq. soln. of Co salt such as cobalt chloride, an aq. soln. of nickel salt such as nickel chloride and an aq. soln. in which a reducing agent, a complex agent, a pH regulating agent and a pH buffer are dissolved are stirred at >=353 K and are mixed, the formed precipitates are separated into solids and liquids, and drying is executed by warm wind to obtain a powdery product. As the reducing agent, sodium hypophosphite or the like is used. As the complexing agent, trisodium citrate or the like is used, and they fulfill functions of disturbing the formation of hydroxides caused by the Co ions and Ni ions and assisting the reduction of these ions. As the pH regulating agent, NaOH or the like is used, and regulation to the pH in which the reducing rate is made high is executed. As the pH buffer, boric acid or the like is used.

Treatment of electroless plating bath

Abstract: PROBLEM TO BE SOLVED: To provide a treatment method for an electroless plating bath capable of easily, surely and inexpensively removing phosphorus acid ions from the aged electroless plating bath in which a large amt. of the phosphorus acid ions accumulate without introducing impurities therein, capable of easily recovering nickel sulfate from the formed and separated nickel phosphite and capable of effectively utilizing the plating bath components or the phosphorus acid ions as a reaction medium. SOLUTION: The operations to adding the nickel sulfate to the electroless plating bath which is prepd. by using a water-soluble nickel salt, its complexing agent and sodium hypophosphite as a reducing agent as essential components and in which the phosphite accumulates to form and settle the nickel phosphite, removing the nickel phosphite to regenerate the electroless plating bath and reusing the bath are repeated. Sulfuric acid or the sulfuric acid and sodium sulfate are added to the separated nickel phosphite to form the nickel sulfate and sodium phosphite or sodium hypophosphite from nickel phosphite and the resulted nickel sulfate is recovered.

A Raney Nickel—Sodium Hypophosphite Combination System for Reductive Desulfurization Without Racemization of Optically Active Secondary Alcohol.

Abstract: Sulfides and sulfoxides bearing an optically active secondary alcohol were desulfurized with a Raney nickel (W-2)-sodium hypophosphite combination system to give optically active alcohols in high yields without racemization . However, the combination system was not effective with sulfides which comprise an alkylthio group and the corresponding sulfoxides. This system exhibited the reductive desulfurization of benzylthio or phenylthio ether in the presence of a benzyl ether.

Determination of Trace Tin by Catalytic Reducing Decoloration Spectrophotometry

Abstract: Catalytic effect of trace tin on decolorizing reaction of acid chrome blue K by reducing with sodium hypophosphite in dilute phosphate acid solution has been studied.Based on this study, a kinetic spectrophotometric method for the determination of trace tin has been established.The detection of the method is 0.0062μg/L tin and the linear range is 0 to 4.0μg/L for tin.Combined with chromatographic separation using tributyl phosphate,the method has been realized the determination of trace tin in geological samples and the results obtained are in good agreement with certified values.