A wiring substrate includes an insulating layer, a pad in a via hole piercing through the insulating layer and exposed at a first surface of the insulating layer, a via conductor on the pad in the via hole, and a wiring part on a second surface of the insulating layer facing away from the first surface. The wiring part is connected to the pad through the via conductor in the via hole.

An LTCC integrated circuit mold unit includes an integrated mold formed by multiple circuit mold units which are superposed, electrodes sheathed in the integrated mold and conductive wire sections sheathed in the integrated mold. Each circuit mold unit is formed by a ceramic base with an electrode pattern recess and a through hole. A denting depth of the electrode pattern recess is between 0.5 μm and 5000 μm. The through hole penetrates through the ceramic base. An inner diameter of the through hole is above 10 μm. The electrode pattern recess is filled with a conductive material to form one of the electrodes. Each through hole is filled with the conductive material to form one of the conductive wire sections. The conductive wire sections which are vertically adjacent are connected to form a conductive path. The conductive path electrically connects to at least one of the electrodes.

A component-embedded substrate includes: insulating layers each including a wiring pattern; an embedded component including a connection terminal; a plurality of vias that electrically connect the connection terminal to the wiring patterns adjacent to each other in a lamination direction. Each of the vias is composed of a via hole in the insulating layer and a conductive material in the via hole. One of the vias is a connection via connected to the connection terminal, and another of the vias is an adjacent via adjacent to the connection via in the lamination direction. The connection via and adjacent via overlap in a plan view. S1/A1≤0.61 and S1/A2≤0.61 are satisfied, where A1 is an average cross-sectional area of the connection via, A2 is an average cross-sectional area of the adjacent via, and S1 is an overlapping area of the connection via and adjacent via in the plan view.

Systems and methods for applying solder to a pin. The methods comprising: disposing a given amount of solder on a non-wetable surface of a planar substrate; aligning the pin with the solder disposed on the non-wetable surface of the planar substrate; inserting the pin in the solder; and/or performing a reflow process to cause the solder to transfer from the planar substrate to the pin.

A circuit board according to an embodiments includes an insulating portion comprising a plurality of insulating layers, wherein the insulating portion includes: a first insulating portion; a second insulating portion disposed on the first insulating portion and having a coefficient of thermal expansion corresponding to the first insulating portion; and a third insulating portion disposed under the first insulating portion and having a coefficient of thermal expansion corresponding to the first insulating portion; wherein the first insulating portion includes a prepreg including glass fibers, and wherein the second and third insulating portions include a resin coated copper (RCC) with a coefficient of thermal expansion in the range of 10 to 65 (10.sup.−6 m/m.Math.k).

A circuit board according to an embodiment includes an insulating layer; and a via portion disposed in a via hole formed in the insulating layer; wherein the via portion includes: a first pad disposed on a lower surface of the insulating layer; a second pad disposed on an upper surface of the insulating layer; a third pad disposed in the via hole and disposed on the first pad; and a connection portion disposed in the via hole and disposed between the second pad and the third pad.

A wiring board includes a pad configured to make an external electrical connection, and an insulating layer. A portion of a lower surface of the pad is covered with the insulating layer. The pad includes a base portion, and an extending portion formed integrally with the base portion and extending toward an outer periphery of a side surface of the base portion in a plan view at a lower end of the side surface of the base portion. The insulating layer is provided with a groove that is located in a periphery of the pad in the plan view, exposes a side surface of the pad, and opens to an upper surface of the insulating layer.

A printed circuit board includes a first board including a plurality of first insulating layers and a plurality of first wiring layers disposed between the plurality of first insulating layers, respectively; and a second board disposed on one surface of the first board and including a plurality of second insulating layers and a plurality of second wiring layers disposed on or between the plurality of second insulating layers, respectively. At least one of the plurality of first insulating layers has a thickness less than a thickness of at least one of the plurality of second insulating layers. The first board further includes a through-via penetrating each of the plurality of first insulating layers and connected to one of the plurality of second wiring layers.

A method for manufacturing a wiring substrate includes preparing a substrate including an insulating layer and metal foils, forming a through hole in the substrate to penetrate through the insulating layer and foils, forming a first plating film on the substrate such that the first film is formed on the entire surface of each metal foil and the inner wall of the hole, laminating one or more resin sheets on the first film such that the resin sheet or sheets cover the first film on the entire surface of a respective one of the foils, pressing the resin sheet or sheets such that resin is extruded from the resin sheet or sheets into the hole and fills space surrounded by the first film inside the hole, removing the resin sheet or sheets, and forming a second plating film on the substrate to cover surface of the resin in the hole.

A wiring board includes a core layer having a first through hole formed therein, a magnetic resin filled inside the first through hole, a second through hole formed in the magnetic resin, and a plating film covering an inner wall surface of the second through hole. The plating film includes an electroless plating film, and an electrolytic plating film. The electroless plating film makes direct contact with an inner wall surface of the second through hole.