Thick film paste via fill composition for use in LTCC applications
View Patent ↗The present invention is directed to the use of a thick film paste composition comprising, in weight percent total paste composition, materials selected from mixtures of lead iron tungstate niobate solid solutions 30 to 80%, calcined mixtures of barium titanate, lead oxide and fused silica 20 to 70%, barium titanate 30 to 50%, calcined mixtures of barium titanate 30 to 50%, barium titanate and calcined mixtures of barium titanate 30 to 50%, lead oxide and fused silica 50-80%, and a lead germanate glass 3-20%, as a thick film paste via fill composition for use in the formation of multilayer low temperature cofired ceramic circuits.
1. A method of producing a co-fired ceramic circuit using a thick film via fill paste composition comprising the steps of:
(i) providing a high dielectric sheet with via holes,
(ii) filling said via holes with said thick film via fill paste composition of BaTiO 3 66 wt %, lead germanate glass 4 wt %, and an organic medium 30 wt %, based upon the weight of the total via fill paste composition, and wherein said lead germanate glass comprises, in weight percent glass, 78.5% Pb 3 O 4 and 21.5% GeO 2 ,
(iii) drying said via fill paste composition in said filled via holes by heating at 120° C. to 150° C.,
(iv) applying a layer of conductor paste to said high dielectric sheet with filled via holes to form at least two layers, and
(v) sintering said at least two layers to form a multilayer low temperature cofired ceramic circuit.