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Presidio Components. Inc.

Daniel F DeVoe

Alan D Devoe

Alan D DeVoe

Metal, normally gold or platinum, is printed, and is adhered by a glass frit, on the top and/or bottom surfaces of a multi-layer laid-up green ceramic wafers containing typically up to 16 layers and 800+ separate devices, typically 800+ monolithic, buried-substrate, ceramic multiple capacitors. The wafer is diced, and the multiple ceramic capacitors each with its patterned surface metal are co-fired. The integrally formed, top and bottom surface, conduction traces connect similarly formed pads, typically disposed in a 'pin-grid' pattern, to later-added side traces or conductive castellations that connect to the electrodes of multiple buried-substrate capacitors. The pads are precisely located, and extend over such ample areas, to support the stable surface mounting, and the reliable electrical connection of, diverse external electrical circuits and components. The surface mounting may be by and of adhering with conductive adhesive, soldering, reflow soldering, gold wire bonded, aluminum wire bonding, flip-chip mounting, die bonding and like processes, including automated processes. The pads on the bottom surface typically support mounting the ceramic multiple capacitor to a printed circuit board, flexible substrate, alumina substrate, multi-chip module or the like. Meanwhile, pads on the top surface typically support the physical mounting and electrical connection of one or more electrical circuits--including ICs--or components piggyback on top of the multiple capacitor, including in a dense three-dimensional multi-tier, tower, arrangement.

Printing and adhering patterned metal on laid-up multi-layer green wafer

Leaded electrical circuits and components, typically receivers and amplifiers used in micro-miniature hearing aids, are closely physically mounted by their leads extending within laser-drilled through-holes, typically three such holes, to multiple buried-substrate capacitors within a monolithic ceramic multiple capacitor. Electrical connection to the leads does not transpire within the holes, but rather though soldered or like connection to conductive pads surrounding the holes and continuing first as circuit traces on the top of the monolith, and then as electrically-conductive trace or castellations on the sides of the monolith, until reaching electrodes of the buried-substrate capacitors patterned so as to be brought to side surfaces of the monolith. The direct electrical connection is normally to multiple plates of plural buried-substrate capacitors, typically including a relatively large, typically 1.0 .mu.farad, capacitor in electrical parallel with a smaller, typically 100 picofarads, capacitor. Both capacitances jointly serve as an effective filter to noise in two separate frequency bands, typically centered about 100 kHz and about 100 MHz.

Close physical mounting of leaded amplifier/receivers to through holes

A monolithic, buried-substrate, ceramic multiple capacitor is laid up as multiple capacitors that are isolated, one to the next, by a dual-dielectric-constant, three-layer-laminate, isolation layer. Each isolation layer has and presents (i) an innermost layer of a low dielectric constant (low K) material, located between (ii) outer laminate layers of a high dielectric constant (high K) material. By such construction negative effects of the physio-chemical reaction (i) occurring at the boundary between the high-K and low-K layers, (ii) contaminating the high-K dielectric and lowering its K, and (iii) undesirably serving both to lower the capacitance of any (buried substrate) capacitor that makes use of the ('contaminated') high-K dielectric while increasing capacitor leakage current, are mitigated or avoided. This occurs because the physio-chemical reaction zone, or band, located between the high-K dielectric layers (from which each buried-substrate capacitor is formed) and the low-K dielectric isolation layer (between successive capacitors) is moved slightly away from the region of the capacitor itself. Moreover, the ceramic multiple capacitor is strongly and stably fused together in its several layers, which different layers of different dielectric constant have different thermal coefficients of expansion, because the outer (high-K) laminate layers of the isolation layer are preferably of intermediary thickness between the innermost (low-K) layer and the (high-K) dielectric layers of the bordering buried-substrate capacitors.

Monolithic, buried-substrate, ceramic multiple capacitors isolated, one

A monolithic multiple ceramic capacitor is made by interspersing layers of green tape containing ceramic powder in a binder with printed layers of electrical conductors, then compressing the layers and heating them to sinter the ceramic powder. Edge connections link the conducting layers in predetermined patterns to provide external connections to the capacitors. Use of parasitic or stray capacitance between pairs of external terminals provides additional useful values of capacitance. Unwanted stray capacitance between adjacent terminals is reduced by making slots by saw cuts or the like in either the green tape or the sintered material. Unwanted stray capacitance between elements inside the capacitor is reduced by ground planes between layers of capacitors and by layers of ceramic materials having relatively low dielectric constants to separate layers of capacitors, to form exterior layers of insulating material, or both.

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Coronado, CA, United States of America

Daniel F DeVoe