Ceramic-filled fluoro:polymer composite for circuit board use - contains specific vol. of filler coated with zirconate or titanate to improve flow properties and chemical resistance at high pH

摘要

The improvement in a ceramic-filled fluoropolymer composite are that the ceramic filler (i) forms 26-50 vol.% of the total substrate material; and (ii) is coated with a zirconate or titanate. The filler pref. contains silica and the substrate material is pref. at least partially coated with a layer of electroconductive material. USE/ADVANTAGE - Use of the composite is claimed as an interlayer adhesive for mutlilayer circuit boards and as a filler for the through-holes of such boards. It retains the good thermal, mechical and electrical properties of higher ceramic filler content compsns. of US4849284, 5061548 and 5024871 (and has the additional advantages of improved flow properties (useful in forming through-hole fillers) and improved chemical resistance at high pH values (useful in electroless Cu plating with highly alkaline baths). Improvement in flow properties is obtd. without increasing the Z-axis heat expansion coefft. . fi