Trw Limited

Other

Electro-science Laboratories, Inc.

Richard L Wahlers

Kenneth M Merz

Vernon E Osborne

Michael Alan Stein

Richard B Tait

Sidney J Stein

Joseph A Tentarelli

John G Woods

Alvin H Feingold

Paul W Bless

Cornelius Y D Huang

Merrill R Heinz

Charles Barclay

This invention describes materials system and processing conditions for manufacturing magnetic circuit components such as induction coils and transformers that are non wire-wound, miniature in size and, have a low manufacturing cost. The materials system of this invention is comprised of: (1) Low Temperature Cofire Ceramic (LTCC) tapes or thick film pastes of ferromagnetic ceramics with a 20 to 750 range of magnetic permeability to form the magnetic core of the components, (2) Thick film buried silver conductor paste to form the planar induction coils on individual magnetic layers, (3) Thick film via-fill silver conductor paste to interconnect two or more of the planar induction coils through the thickness of the magnetic layers, (4) Thick film silver solderable top layer conductor paste compatible with the ferrite and, (5) Thick film dielectric paste with low magnetic permeability to redirect the magnetic flux for enhancing the magnetic coupling coefficient and to insulate the silver conductors for enhancing the dielectric breakdown voltage. The key characteristics of the materials system of this invention that facilitate manufacture of low cost non wire-wound, miniature magnetic circuit components are: (1) Mutual compatibility essential for either of the techniques, the cofire technique or the sequential technique, used for manufacturing multilayer hybrid microelectronic components, (2) Complementary thermo-physical properties such as shrinkage and thermal expansion coefficient essential for manufacturing flat multilayer magnetic components, (3) Magnetic components with magnetic coupling coefficients greater than 0.95 under optimal processing conditions and, (4) Magnetic components with dielectric breakdown voltage greater than 500V/mil under optimal processing conditions.

Materials system for low cost, non wire-wound, miniature, multilayer magnetic circuit components

The present invention relates to dielectric materials which may be used in the manufacture of, e.g., low profile heaters. Such dielectric materials comprise at least about 50% of a glass composition having about 35-50% SiO.sub.2, about 30-40% of an alkaline earth metal oxide selected from the group consisting of CaO, MgO, and SrO, about 13--22% Al.sub.2 O.sub.3, and about 0-10% B.sub.2 O.sub.3, the percentages being weight percentages based on the weight of the total glass composition. Certain dielectric compositions of the disclosure have a linear thermal expansion coefficient in the range of about 6.0 to 9.0 ppm/.degree. C.

Dielectric pastes and tapes, and metal substrates coated therewith

A vitreous enamel resistor material comprising a mixture of a vitreous glass frit and fine particles of tin oxide (SnO.sub.2). An electrical resistor is made from the resistor material by applying the material to a substrate and firing the coated substrate to a temperature between about 850.degree. C. and 1150.degree. C. at which the glass melts. Upon cooling, the substrate has on the surface thereof, a film of the glass having the particles of the tin oxide embedded therein and dispersed therethroughout. The resistor material provides a resistor having a resistivity within a wide range and a low temperature coefficient of resistance.

Electrical resistor material, resistor made therefrom and method of

A vitreous enamel resistor material comprising a mixture of a vitreous glass frit and fine particles of tin oxide (SnO.sub.2). An electrical resistor is made from the resistor material by applying the material to a substrate and firing the coated substrate to a temperature at which the glass melts. The tin oxide is preferably heat treated prior to mixing with the glass frit. Upon cooling, the substrate has on the surface thereof, a film of the glass having the particles of the tin oxide embedded therein and dispersed therethroughout. The resistor material provides a resistor having a wide range of resistivity and a low temperature coefficient of resistance.

A vitreous enamel resistor material comprising a mixture of a vitreous glass frit, an insulating material containing an oxide of zirconium, and a conductive phase of fine particles of tin oxide. The insulating material is selected from the group consisting of zirconia (ZrO.sub.2), calcium zirconate (CaZrO.sub.2), barium zirconate (BaZrO.sub.3) and strontium zirconate (SrZrO.sub.3), and the conductive phase may also contain an additive such as tantalum oxide. An electrical resistor is made from the resistor material by applying the material to a substrate and firing the coated substrate to a temperature at which the glass softens. Upon cooling, the substrate has on the surface thereof a film of glass and insulating material having the particles of the conductive phase embedded therein and dispersed therethroughout. The resistor material provides a resistor having relatively high resistivity as well as rugged physical characteristics.

Resistance material, resistor and method of making the same

A method of making a thin nickel film temperature sensitive device with a relatively high positive temperature coefficient of resistance utilizing a film of nickel deposited from a bulk nickel source onto an electrically insulating substrate, and device made thereby including the step of heat treating a resistor element having a thin film of nickel deposited on an electrically insulating substrate by heating in a reducing atmosphere to a peak temperature of at least 550.degree. C., over a heating cycle of at least about 20 minutes. The nickel film of the heat treated resistor element has a selected temperature coefficient of resistance which is at least 60% of the value of the coefficient for the bulk nickel and a sheet resistance of at least one ohm per square which properties are determined by the heat treating temperature and cycle time, and the thickness of the nickel film. The resistor element can be made by vacuum depositing the nickel film to the desired thickness onto the insulating substrate, and affixing terminations to the ends of the resistor element and applying a protective outer coating to the nickel film after the heat treating of the element.

Method of making temperature sensitive device and device made thereby

A vitreous enamel resistor material comprising a mixture of a glass frit, and fine particles of tin oxide (SnO.sub.2), a primary additive of particles of oxides of manganese, nickel, cobalt or zinc, and a supplemental additive of oxides of tantalum, niobium, tungsten or nickel. An electrical resistor is made from the resistor material by applying the material to a substrate and firing the coated substrate to a temperature at which the glass melts. The tin oxide may be heat treated prior to mixing the glass frit. Upon cooling, the substrate has on the surface thereof, a film of the glass having the particles of the mixture embedded therein and dispersed therethroughout. The resistor material provides a resistor having a wide range of resistivities and a low temperature coefficient of resistance.

A vitreous enamel resistor material comprising a mixture of a vitreous glass frit and fine particles of a mixture of tin oxide (SnO.sub.2) and tantalum oxide (Ta.sub.2 O.sub.5). An electrical resistor is made from the resistor material by applying the material to a substrate and firing the coated substrate to a temperature at which the glass melts. The oxide mixture may be heat treated prior to mixing with the glass frit. Upon cooling, the substrate has on the surface thereof a film of the glass having the particles of the oxides embedded therein and dispersed therethroughout. The resistor material provides a resistor having a high resistivity and a low temperature coefficient of resistance.

Growing community of inventors

Churchville, PA, United States of America

Richard L Wahlers