In some implementations, a substrate comprises a ceramic core, multiple metal-filled vias through the ceramic core, and a first metal layer, on a top side of the ceramic core, including metal traces, over respective metal-filled vias. The substrate comprises a second metal layer, including a first electrical contact over a first metal trace, a second electrical contact over a second metal trace, and a third electrical contact over a third metal trace, where the second metal trace is electrically isolated from the first and third metal traces. The substrate comprises a thin dielectric layer separating the first metal layer and the second metal layer. The dielectric layer between the first metal layer and the second layer provides the substrate with a low parasitic inductance and a low thermal resistance based on a thickness of the dielectric layer and/or a material used for the dielectric layer.

A circuit board structure includes a substrate, a third dielectric layer, a fourth dielectric layer, a first external circuit layer, a second external circuit layer, a conductive through hole electrically connected to the first and second external circuit layers, a first annular retaining wall surrounding the conductive through hole, and a second annular retaining wall surrounding the conductive through hole. The first annular retaining wall is electrically connected to the first external circuit layer and a first inner circuit layer. The second annular retaining wall is electrically connected to the second external circuit layer and a second inner circuit layer. A first ground circuit, the first annular retaining wall, and the first inner circuit layer define a first ground path surrounding a first signal circuit. A second ground circuit, the second annular retaining wall, and the second inner circuit layer define a second ground path surrounding a second signal circuit.

A package substrate has a dielectric layer and a redistribution metal layer. The dielectric layer has a first dielectric material and a second dielectric material. The first dielectric material is different than the second dielectric material. The second dielectric material may have a dielectric constant that is either greater than or less than the dielectric constant of the first dielectric material. The second dielectric may be selected based on a specific target application such as single-ended signal routing or serializer/deserializer (SERDES) routing.

In an embodiment, a structure includes a core substrate, a redistribution structure coupled, the redistribution structure including a plurality of redistribution layers, the plurality of redistribution layers comprising a dielectric layer and a metallization layer, a first local interconnect component embedded in a first redistribution layer of the plurality of redistribution layers, the first local interconnect component comprising conductive connectors, the conductive connectors being bonded to a metallization pattern of the first redistribution layer, the dielectric layer of the first redistribution layer encapsulating the first local interconnect component, a first integrated circuit die coupled to the redistribution structure, a second integrated circuit die coupled to the redistribution structure, an interconnect structure of the first local interconnect component electrically coupling the first integrated circuit die to the second integrated circuit die, and a set of conductive connectors coupled to a second side of the core substrate.

A flexible circuit board includes an electrically insulating cover layer, at least one electrical component arranged on the upper side of the cover layer with electrical contacts, a conducting track structure arranged on the underside of the cover layer and with contact regions, wherein the electrical contacts are each electrically conductively connected to one of the contact regions through one of a plurality of openings in the cover layer, a heat sink which is thermally conductively connected to each electrical component through the cover layer, and a layer with high conductivity. To create an improved cooling capacity of the electrical component, the heat arising in the electrical components is first dissipated effectively within the conducting paths of the conducting path structure and then dissipated out of the conducting paths directly into the heat sink by the layer with high heat conductivity.

A method for manufacturing a circuit board is disclosed. An inner wiring base board with a first opening is provided. A base board is fixed in the first opening, and a first wiring base board and a second wiring base board are pressed on opposite surfaces of the inner wiring base board. The base board is made of ceramic and has a high light reflectivity of 92% to 97%. A first conductor layer and a second conductor layer are formed on opposite surfaces of the laminated structure. The first conductor layer includes a plurality of connecting pads on the base board. A solder mask is formed on an outer side of the first conductor layer, the solder mask has a high light reflectivity of 92% to 95%, and the base board is exposed outside the solder mask.

An electronic circuit including a substrate having a first dielectric characteristic. The substrate can include a first side and a second side. An intermediary material can be disposed within the substrate. For instance, the intermediary material can be located between the first side and the second side. The intermediary material can include a second dielectric characteristic, where the second dielectric characteristic is different than the first dielectric characteristic. A first conductive layer can be disposed on the first side, and a second conductive layer can be disposed on the second side. A conductive path can be electrically coupled between the first conductive layer and the second conductive layer. The conductive path can be in contact with at least a portion of the intermediary material.

Various circuit boards and methods of fabricating and using the same are disclosed. In one aspect, a system is provided that has a circuit board with a pocket and a conductor layer. A chiplet is positioned in the pocket. The chiplet has plural bottom side interconnects electrically connected to the conductor layer and plural top side interconnects adapted to interconnect with two or more semiconductor chips.

The leadframe substrate mainly includes a modulator, a plurality of metal leads, a resin layer and a crack inhibiting structure. The resin layer provides mechanical bonds between the modulator and the metal leads disposed about peripheral sidewalls of the modulator. The crack inhibiting structure includes a continuous interlocking fiber sheet that covers the modulator/resin interfaces, so that the segregation induced along the modulator/resin interfaces or cracks formed within the resin layer can be prevented or restrained from extending to the top surfaces, thereby ensuring the signal integrity of the flip chip assembly.

A multilayer printed circuit board is provided having a first conductive layer and a first plating resist selectively positioned within the first conductive layer. A second plating resist may be selectively positioned within a second conductive layer. A through hole extends through the first plating resist in the first conductive layer and the second plating resist in the second conductive layer. An interior surface of the through hole is plated with a conductive material except along a length between the first plating resist and the second plating resist. This forms a partitioned plated through hole having a first via segment electrically isolated from a second via segment.