Shoei Chemical Inc.

Shoei Kagaku Kogyo Kabushiki Kaisha

Eiichi Asada

Yuji Akimoto

Kazuro Nagashima

Toshio Inokuma

Tetsuya Tanaka

Mineto Iwasaki

Mikio Yamazoe

Kazurou Nagashima

Shinichi Ono

Masayuki Maekawa

Hiroshi Yoshida

Fumiyuki Shimizu

Yiyi Ma

Isao Egawa

Hiroyuku Saito

Kenichi Hirano

Masahiro Yata

Kazuo Yokoyama

Shigeru Matsumura

Toshio Matsuhashi

Hiromu Sasaki

A metal powder having a vitreous thin layer on at least a part of the surface thereof wherein the amount of the vitreous thin layer is preferably 0.01 to 50% by weight based on the metal powder without the vitreous thin layer. The metal powder is prepared by a process comprising the steps of: bringing a solution comprising a heat-decomposable metal compound to fine droplets; and heating the droplets to a temperature above the decomposition temperature of the metal compound, wherein a precursor of an oxide, heat-decomposable to produce a vitreous material which, together with the metal, does not form a solid solution, is added to the solution and the vitreous material is deposited, upon the heating, in the vicinity of the surface of the metal powder. The powder is useful for the preparation of a thick film paste used in a multilayer ceramic electronic component or substrate, since it has an excellent oxidation resistance during storage, in a conductor paste, and during firing of the paste.

Metal powder and process for preparing the same

A nickel powder having at at least part of the surface thereof a layer of a composite oxide represented by the formula: A.sub.x B.sub.y O.sub.(x+2y), wherein A stands for at least one element selected from the group consisting of Ca, Sr and Ba; B stands for at least one element selected from the group consisting of Ti and Zr; and x and y represent numbers satisfying the formula: 0.5.ltoreq.y/x.ltoreq.4.5). The nickel powder may further contains at least one selected from among boron oxide, aluminum oxide and silicon oxide. The nickel powder is produced by spray pyrolyzing a solution of thermal decomposable starting compounds of nickel and additive elements and the resultant powder is suitable for use in a thick-film conductor paste having a sintering-starting temperature close to that of ceramic layers and a shrinkage behavior close to that of a ceramic without detriment to the conductivity and electric properties thereof.

Nickel powder and process for preparing the same

A process for preparing a metal powder, comprising the steps of: bringing a solution comprising at least one metal salt to fine droplets; and heating the droplets to a temperature above the decomposition temperature of the metal salt, wherein at least one compound which is heat-decomposable to produce a metal, a semimetal or an oxide of the metal or semimetal capable of remaining unmelted upon heating at the heat temperature is added to the solution and at least one selected from the group consisting of the metal, semimetal and oxide is heat-segregated in the vicinity of the surface of the metal powder. The resultant metal powder has a uniform particle size and good dispersibility without fusing or aggregation and is useful for the preparation of thick film pastes used in electronic circuits or components.

Process for preparing metal powder

A nickel powder having a composite oxide layer comprising lanthanum and nickel and, optionally an oxide of chromium, on at least a part of the surface thereof. The nickel powder is produced by a process comprising the steps of: bringing a solution comprising at least one heat-decomposable nickel compound and at least one heat-decomposable lanthanum compound and, optionally, at least one heat-decomposable chromium compound, to fine droplets; and heating the droplets at a temperature above the decomposition temperatures of these compounds to prepare a nickel powder and, at the same time, to deposit a composite oxide layer comprising lanthanum and nickel and, when present, chromium oxide, in the vicinity of the surface of the nickel powder. The nickel powder is suitable for use in a conductor paste to be co-fired with unfired ceramic green sheets for a multilayer component or the like because the sintering initiation of the powder is effectively delayed to around the sintering initiation temperature of the ceramic green sheets, thereby preventing the problems caused due to excessive sintering.

Nickel powder containing a composite oxide of La and Ni and process for

A lead-free insulating glass composition comprises (A) 50 to 85 wt. % of a glass comprising, on a weight basis, 28 to 38% of SiO.sub.2, 4 to 10% of B.sub.2 O.sub.3, 8 to 16% of Al.sub.2 O.sub.3, 15 to 23% of MgO, 1 to 12% of CaO, 3 to 9% of BaO, 8 to 16% of ZnO, and 3 to 8% of ZrO.sub.2 ; and (B) 50 to 15 wt. % of at least one filler selected from the group consisting of alumina and zircon. When using this glass composition as an insulating layer of a thick-film multilayer circuit board, there can be obtained a highly reliable thick-film multilayer circuit board in which the warpage of the substrate and leakage current are greatly reduced and the withstand voltage is highly improved.

Insulating glass composition

A nontoxic lead-free conductive paste comprising (a) a lead-free glass frit having a crystallization temperature of 700.degree.-870.degree. C. and consisting essentially of, by weight %, 20-38% of SiO.sub.2, 5.5-13.5% of B.sub.2 O.sub.3, 8-15.5% of Al.sub.2 O.sub.3, 4-19% of CaO, 20-29% of ZnO, 0-6% of ZrO.sub.2, 4-16% of TiO.sub.2 and 0.1-3.8% of MoO.sub.3 ; (b) finely divided particles of electrically conductive material; (c) at least one inorganic additive selected from the group consisting of bismuth oxide, zinc oxide-containing containing oxide material, manganese oxide, copper oxide and molybdenum oxide; and (d) an organic medium. The nontoxic conductive paste is free from environmental and health problems and results in conductors having excellent solderability, solder leach resistance, adhesion strength and electrical properties, both on ceramic substrates such as alumina or on dielectric bodies.

Lead-free conductive paste

A multilayered ceramic capacitor having internal electrodes comprising a substantially single-crystal metallic powder as a conductor, the powder having been produced by spraying a solution containing at least one metal salt to form droplets and heating the droplets to a temperature higher than the decomposition temperature of the metal salt and the melting point of the metal. When the metal salt forms an oxide at a temperature not higher than the melting point of the metal, the droplets are heated to a temperature higher than the decomposition temperature of the oxide. The multilayered capacitor is free from generated cracks in the ceramic material.

Multilayered ceramic capacitor

An oxidation-resistant palladium powder containing one or more alkaline earth metal elements in a total amount of at least 0.005% by weight relative to Pd. The palladium powder is useful as a conductive component of a thick-film conductive paste and the resultant conductive paste can provide internal electrodes to a multilayered ceramic capacitor with minimized structural defects such as cracks or delamination. The palladium powder is produced by spraying a palladium salt solution containing one or more alkaline earth metal elements to form droplets and heating the droplets to a temperature of at least 1000.degree. C. The preferred amount of the alkaline earth metal elements in the Pd powder is from 0.005 to 0.1% by weight relative to Pd and the preferred alkaline earth metal elements are one or more elements selected from the group consisting of Mg, Ca, Sr and Ba.

Oxidation-resistant palladium powder, production method thereof and

A resistor composition comprising at least one electrically conductive powder selected from the group consisting of (a) tin oxide power and (b) powder resulting from heat treatment of tin oxide and tantalum oxide, a glass frit and double oxide of tantalum dispersed in an organic vehicle. In the resistor composition, the mixing amount of the double oxide of tantalum is preferably 30 parts by weight or less with respect to 100 parts by weight of the sum of the electrically conductive powder and the glass frit. The resistor composition provides highly reproducible thick film resistors having superior properties and high stability over a wide range of resistance by addition of the tantalum double oxides.

Resistor composition

A bonding wire for use in semiconductor devices which consists essentially of 0.0003 to 0.01 wt. % of barium and the balance gold, the gold purity of said bonding wire being at least 99.99%. The bonding wire may further contain at least one element selected from the group consisting of 0.0005 to 0.005 wt. % of aluminum, 0.0001 to 0.003 wt. % of calcium, 0.0005 to 0.005 wt. % of silver and 0.0005 to 0.005 wt. % of palladium. The total content of the elements and barium in the bonding wire should not exceed 0.01 wt. % based on the weight of the bonding wire so that the gold purity of the bonding wire is at least 99.99%. The use of the additive elements improve the mechanical strength and wire-bondability, making the bonding wire highly suitable for use in wire bonding of semiconductor elements, especially for high-speed bonding.

Bonding wire

A resistor composition comprising conductive particles, a glass frit and a vehicle in which RuO.sub.2 particles coated with a polynary oxide of Bi and/or Pb and Ru are employed and, by using the surface-coated RuO.sub.2, the composition can provide readily a improved resistor having a advantageous combination of properties, particularly a very small absolute TCR and high voltage stability throughout a wide resistance range. The produced resistor can be successfully laser-trimmed without adversely affecting the properties thereof.

Resistor compositions

Resistor compositions are disclosed which comprise: (a) ruthenium oxide; (b) glass; (c) at least one metal oxide selected from the group consisting of lanthanum oxide, neodymium oxide, praseodymium oxide and samarium oxide; and (d) an organic vehicle. Resistors are produced using this composition by firing a resistor film comprising ruthenium oxide, glass and at least one metal oxide selected from the group consisting of lanthanum oxide, neodymium oxide, praseodymium oxide and samarium oxide onto an electrically insulating substrate. The use of the metal oxides in the resistor compositions surprisingly improve the TCR (temperature coefficient of resistance) particularly in high resistance ranges, and brings the TCR close to zero. In addition to the effect of improving the TCR, the metal oxides increase resistance and improve noise and VCR (voltage coefficient of resistance) properties.

Resistor compositions and resistors produced therefrom

A thick film resistor comprising a resistive film element comprising 100 parts by weight of RuO.sub.2 and glass and 0.1 to 15 parts by weight of Au, electrodes containing not less than 50 weight percent of Ag therein connected to the terminal portions of the resistive film element, and an insulating substrate on which the resistive film element and the electrodes are formed.

Thick film resistor

A method and apparatus for preparing uniformly-sized particles wherein a first liquid reactant is chemically reacted with a second liquid reactant to form precipitated particles of substantially uniform particle size which comprises forming substantially uniformly-sized droplets of one of said reactants and directing said droplets against the falling flow of the other of said reactants.

Method and apparatus for preparing uniformly-sized fine particles

A resistor composition and process for making the same which comprises a conductive material, a glass frit and a vehicle therefor or a conductive material, a glass frit, an insulating or semiconductive metal oxide and a vehicle therefor, the weight ratio of said conductive material, said glass frit and said metal oxide, when the latter is present, being maintained substantially constant, wherein the resistance value of said composition is established by varying the total surface area of said conductive material, and said glass frit and, when applicable, said metal oxide, without changing the temperature coefficient of resistance of said composition.

Growing community of inventors

Tokyo, Japan

Eiichi Asada