Ceramics Process Systems Corporation

Roger S Lind

Eric A Barringer

Brian C Foster

James D Hodge

Ellen S Tormey

Charles E Swain

Dense vias may be made with a metallizing composition containing tungsten, alumina, and either nickel or palladium. Further, an infiltration process ensures that vias in ceramic substrates are heremetic. Infiltrating materials, including metals and alloys, are applied to co-fired substrates and the composite is fired. The process may be repeated if necessary. Alternatively, the via holes may be bore-coated prior to infiltrating.

Substrates with dense metal vias

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

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.

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Acton, MA, United States of America

Roger S Lind