Ceramics Process Systems Corporation

Massachusetts Institute of Technology

Eric A Barringer

Thomas W Eagar

Sheldon I Lieberman

James D Hodge

Brian C Foster

Roger S Lind

William C Gruber

Mark S Schmidt

Lewis A Walton

George S Pabis

Julius M Ullmann

Donald J Kelley

Anne R Austin

Richard Waack

Martha A Gilliam

Ellen S Tormey

Charles E Swain

Brian W Saxton

M Bruce Fegley, Jr

H Kent Bowen

Jean H Raas

Metallization, applied by the thick film screening technique, utilized herein has glass-ceramic bonding agents designed to promote adhesion yet maintain the desired electrical properties and post-processing characteristics.

Metallic inks for co-sintering process

Bonding additives for refractory metallization compositions allow for circuit traces having good resistivities and adhesion values in excess of 6 kpsi, generally between about 10 and 20 kpsi. The inks are provided in formulations devoid of a glass component, and are suitable for co-sintering circuit traces and vias with 96% alumina substrates, and especially for 99% alumina substrates. Suitable bonding additives are the oxides of molybdenum, tungsten, niobium, manganese, yttrium, and titanium, or mixtures of such oxides.

Bonding additives for refractory metallization inks

Glass-ceramic packages for integrated circuits containing multi-layer, interconnected thick film wiring patterns are obtained by co-sintering a glass-ceramic composite and copper, silver, palladium, gold, based conductors at temperatures not exceeding about 1000.degree. C. The dielectric systems include composites of borosilicate glasses and crystalline fillers which are fabricated by either mixing glass frit and the filler or by a sol-gel coating process. The package is fabricated using a tape specifically designed for clean binder burnout in a reducing atmosphere at low temperatures and also for superior mechanical and thermal properties. Metallization, applied by the thick film screening technique, utilized herein has glass-ceramic bonding agents designed to promote adhesion yet maintain the desired electrical properties and post-processing characteristics.

Co-fired metal-ceramic package

A tungsten paste suitable for co-sintering with 98+% alumina substrate can be produced by adding selected compositions of glass to the paste. Circuit packages produced in accordance with the present invention exhibit superior thermal conductivity, low shrinkage variability, and smoother and more homogeneous surface finish. A preferred embodiment of the invention utilizes a substrate comprising narrow size range alumina powder, thus yielding lower sintering temperature and further improvements in shrinkage variability and surface finish.

Tungsten paste for co-sintering with pure alumina and method for

This invention relates to glass-ceramic packages for integrated circuits containing multi-layer, interconnected thick film wiring patterns obtained by co-sintering a glass-ceramic composite and copper, silver, palladium or gold based conductors at temperatures not exceeding about 1000.degree. C. The dielectric systems disclosed herein contains composites of borosilicate glasses and crystalline fillers which are fabricated by either mixing glass frit and the filler or by a sol-gel coating process.

Method for producing materials for co-sintering

Substrates consisting of at least 98% narrow size distribution ceramic particles are co-sinterable with metallized paste to which selected compositions of glass have been added. Substrates produced in accordance with the present invention exhibit superior thermal conductivity, low shrinkage variability, and smoother and more homogeneous surface finish.

Alumina materials for low temperature co-sintering with refractory

A welding flux binder and welding flux comprising the reaction product of a hydrolyzed and polymerized organometallic compound selected from the group consisting of metal alkoxides including tetraalkylorthosilicate, tetraalkylorthotitanate, tetraalkylorthozirconate and trialkylaluminate, metal esters, and metal oxalates. The organometallic compound is hydrolyzed and then polymerized to form a gel glass phase. Alkali and alkaline earth salts are added to stabilize and reduce the viscosity of the gel. The resulting welding flux binder and flux are non-hygroscopic and have a high fired strength.

Non-hygroscopic welding flux binders

A welding flux binder is provided which comprises an alkali-alkaline earth silicate hydrolyzed and polymerized from tetraalkylorthosilicate, Si(OR).sub.4, wherein R is --CH.sub.3, --C.sub.2 H.sub.5, or --C.sub.3 H.sub.7, and alkali and alkaline earth salts. The reaction product of the tetraalkylorthosilicate and metal salts, M.sub.2 O.M'O.SiO.sub.2, where M is potassium, sodium or lithium, and M' is magnesium, calcium or barium, has several advantages as a welding flux binder. For example, it is not hygroscopic and can be prepared at low temperatures since the alkali ions lower the melting point for viscous sintering of the gel phase. Because of the low temperature processing, a wide variety of solid additives with low thermal stability, such as some metals, carbonates, and fluorides, can be incorporated into the flux. Other dopants may also be readily incorporated into the binder during the gel phase.

Uniform-size, high-purity, spherical oxide powders are formed by hydrolysis of alkoxide precursors in dilute alcoholic solutions. Under controlled conditions (concentrations of 0.03 to 0.2 M alkoxide and 0.2 to 1.5 M water, for example) oxide particles on the order of about 0.05 to 0.7 micron can be produced. Methods of doping such powders and forming sinterable compacts are also disclosed.

Growing community of inventors

Waltham, MA, United States of America

Eric A Barringer