A composite circuit board includes an insulation layer, an inner circuit layer, a first conductive layer and a second conductive layer embedded in the insulation layer, a third conductive layer and a fourth conductive layer formed on opposite surfaces of the insulation layer. The third conductive layer electrically connects with the first conductive layer. The fourth conductive layer electrically connects with the second conductive layer. The inner circuit layer is in a middle portion of the insulation layer. The first conductive layer and the second conductive layer respectively forms on opposite sides of the inner circuit layer. The insulation layer forms a plurality of first through holes between the first conductive layer and the inner circuit layer, a plurality of second through holes between the second conductive layer and the inner circuit layer.

An electronic module on a flexible planar circuit substrate with a conductor configuration on a first substrate surface and a plurality of electronic components on the opposite, second substrate surface, wherein the components have component contacts, which are electrically connected selectively by way of vias in the circuit substrate and the conductor configuration, wherein the circuit substrate is a thermoplastic polymer and the component contacts are melted or thermally pressed into the second substrate surface in the region of the vias.

A wiring substrate includes a first wiring layer on a surface of a first insulating layer; a via interconnect including a first portion connected to the first wiring layer and a second portion formed monolithically with the first portion and extending from an end of the first portion in a direction away from the first wiring layer; a second insulating layer on the first insulating layer; and a second wiring layer on the second insulating layer, contacting a first surface of the second portion. The area of a cross section of the first portion, parallel to the surface of the first insulating layer, increases as the position of the cross section approaches the first wiring layer from the second portion. The second portion includes a second surface that is opposite from its first surface and extends horizontally from the end of the first portion to overhang the first portion.

A printed wiring board includes a first conductor layer, a resin insulating layer formed on the first conductor layer, a second conductor layer formed on a surface of the resin insulating layer, and a via conductor formed in the resin insulating layer such that the via conductor is connecting the first and second conductor layers and has a land portion extending on a boundary part of the resin insulating layer. The via conductor is formed in a via hole formed in the resin insulating layer. The resin insulating layer is formed such that the boundary part has a surface roughness that is larger than a surface roughness of the surface on which the second conductor layer formed and that an inner wall surface in the via hole in the resin insulating layer is equal to or larger than the surface roughness of the boundary part of the resin insulating layer.

A method for producing a via-filled substrate includes a metal film forming step of forming a metal film containing an active metal on a hole part wall surface of an insulating substrate having a hole part, a filling step of filling a conductor paste having a volume change rate before and after firing of 10 to 20% in the hole part in which the metal film is formed, and a firing step of firing the insulating substrate in which the conductor paste is filled.

A composite circuit board includes an insulation layer, an inner circuit layer, a first conductive layer and a second conductive layer embedded in the insulation layer, a third conductive layer and a fourth conductive layer formed on opposite surfaces of the insulation layer. The third conductive layer electrically connects with the first conductive layer. The fourth conductive layer electrically connects with the second conductive layer. The inner circuit layer is in a middle portion of the insulation layer. The first conductive layer and the second conductive layer respectively forms on opposite sides of the inner circuit layer. The insulation layer forms a plurality of first through holes between the first conductive layer and the inner circuit layer, a plurality of second through holes between the second conductive layer and the inner circuit layer.

A manufacturing method of a circuit board includes: performing a first printing process to form a first insulating layer having a first circuit depressed pattern; performing a second printing process to form a first circuit layer in the first circuit depressed pattern; checking whether a real position of the first circuit layer is diverged from a predetermined position; determining whether the shift level of the position of the first circuit layer is more than a predetermined level; performing the first printing process to form the second insulating layer, wherein when the shift level is more than the predetermined level and the thickness of a second insulating layer to be formed on the first insulating layer is not greater than a tolerance thickness, the second insulating layer has a hole at least partially overlapping the real position; and performing the second printing process to form a conductive plug in the hole.

In some embodiments, methods include drilling one or a plurality of PTHs with any industrial grade drill to fabricate holes with positive etch back, flooding the PTHs with a dilute solution of an acrylate monomer/oligomer containing an appropriate level of peroxide initiator, polymerizing the acrylate, and then rising the PTHs with the solvent used in the formulation of the acrylate material. In one embodiment, the printed circuit board may include a substrate comprising a plurality of metal layers separated by a plurality of insulating layers; a plurality of plated through holes formed in the substrate, each plated through hole comprising: recesses formed at each insulating layer, copper lands between the recesses, a polymer coating in each recess, and a metal layer lining the plated through hole.

A method of making printed circuit board vias using a double drilling and plating method is disclosed. A first hole is drilled in a core, the first hole having a first diameter. The first hole is filled and/or plated with an electrically conductive material. A circuit pattern may be formed on one or two conductive layers of the core. A multilayer structure may then be formed including a plurality of cores that also include pre-drilled and plated via holes, wherein at least some of the pre-drilled and plated via holes are aligned with the first hole. A second hole is then drilled within the first hole and the aligned pre-drilled and plated holes, the second hole having a second diameter where the second diameter is smaller than the first diameter. A conductive material is then plated to an inner surface of the second hole.

Fuse assemblies are disclosed. In one implementation, a fuse assembly may be disposed that includes a first portion of the second portion. The first portion may be formed of a first metal. The second portion may be formed of a second metal different from the first metal. The second metal may be copper, and the copper may be tin plated or silver plated.