A circuit board includes a first dielectric material, a second dielectric material, a third dielectric material, a first external circuit layer, a second external circuit layer, multiple conductive structures, and a conductive via structure. Dielectric constants of the first, the second and the third dielectric materials are different. The first and the second external circuit layers are respectively disposed on the first and the third dielectric materials. The conductive via structure at least penetrates the first and the second dielectric materials and is electrically connected to the first and the second external circuit layers to define a signal path. The conductive structures are electrically connected to each other and surround the first, the second and the third dielectric materials. The conductive structures are electrically connected to the first and the second external circuit layers to define a ground path surrounding the signal path.

A circuit board includes a first dielectric material, a second dielectric material, a third dielectric material, a first external circuit layer, a second external circuit layer, multiple conductive structures, and a conductive via structure. Dielectric constants of the first, the second and the third dielectric materials are different. The first and the second external circuit layers are respectively disposed on the first and the third dielectric materials. The conductive via structure at least penetrates the first and the second dielectric materials and is electrically connected to the first and the second external circuit layers to define a signal path. The conductive structures are electrically connected to each other and surround the first, the second and the third dielectric materials. The conductive structures are electrically connected to the first and the second external circuit layers to define a ground path surrounding the signal path.

Method for providing an electrical connection, comprising connecting a first cable to a first conducting structure on a printed circuit board, connecting a second cable to a second conducting structure on the printed circuit board, comparing a propagation delay of a first signal path comprising the first cable and the first conducting structure on the printed circuit board, and a propagation delay of a second signal path comprising the second cable and the second conducting structure on the printed circuit board; and removing conductive material of the first conducting structure and/or of the second conducting structure, in order to modify an electrical length of the first conducting structure and/or of the second conducting structure, to obtain a first conducting path and a second conducting path, in dependence on a result of the comparison, in order to reduce a difference of the propagation delays between the first signal path and the second signal path.

Provided is a wiring circuit board that allows the electrical connection between the elements and the terminals to be easy and sure. The wiring circuit board includes an insulating base layer, a plurality of wires with different thicknesses from each other, and an insulating cover layer sequentially toward an upper side. The wires include a first wire having the greatest thickness. The wiring circuit board further includes a plurality of terminals disposed on an upper surface of the insulating base layer. The terminals are electrically connected with the wires, respectively. The upper surfaces and of the terminals are each located at an upper side as compared to an upper surface of the insulating cover layer (a wire covering portion) covering the first wire.

A printed circuit board according to an embodiment includes: an insulating layer; and a circuit pattern disposed on the insulating layer, wherein the circuit pattern includes an upper surface, a lower surface, a first side surface, and a second side surface, and surface roughness Ra of at least three surfaces of the upper surface, the lower surface, the first side surface, and the second side surface of the circuit pattern is 0.1 μm to 0.31 μm.

A method for producing a wiring circuit board includes a first step of preparing a wiring circuit board assembly sheet including a support sheet, a plurality of wiring circuit boards supported by the support sheet, and a joint connecting the support sheet to the plurality of wiring circuit boards, having flat-shaped one surface and the other surface facing one surface at spaced intervals thereto in a thickness direction, and having a thin portion in which the other surface is recessed toward one surface and a second step of forming a burr portion protruding toward the other side in the thickness direction and cutting the thin portion.

In a printed wiring board, when a plurality of wiring base bodies are collectively stacked, a constituent material of a first layer of an insulating resin film has a low melting point, so that the first layer is easily melted. Therefore, thermal welding on an upper surface of the wiring base body is reliably performed, and the wiring base bodies are bonded to each other with high reliability.

Techniques and mechanisms for mitigating the effect of signal noise on communication via an interconnect. In an embodiment, a substrate includes an interconnect and a conductor which has a hole formed therein. Portions of the interconnect variously extend over a side of the conductor, wherein another recess portion of the interconnect extends from a plane which includes the side, and further extends at least partially into the hole. The configuration of the recess portion extending within the hole may contribute to an impedance which dampens a transmitter slew rate of the communication. In an embodiment, a total distance along a path formed by the interconnect is equal to or less than 5.5 inches.

A printed wiring board includes a base insulating layer, a conductor layer including first and second pads, a solder resist layer covering the conductor layer and having first opening exposing the first pad and second opening exposing the second pad, a first bump including base plating layer in the first opening and top plating layer on the first base layer, and a second bump including base plating layer in the second opening and top plating layer on the base layer. The second opening has smaller diameter than the first opening, and the second bump has smaller diameter than the first bump. The first base layer has flat upper surface or first recess having depth of 20 μm or less in upper central portion. The second base layer has flat upper surface, raised portion in upper central portion, or second recess shallower than the first recess in the upper central portion.

A wiring board includes: an insulating layer; and a connection terminal formed on the insulating layer. The connection terminal includes a first metal layer laminated on the insulating layer, a second metal layer laminated on the first metal layer, a metal pad laminated on the second metal layer, and a surface treatment layer that covers an upper surface and a side surface of the pad and that is in contact with the upper surface of the insulating layer. An end portion of the second metal layer is in contact with the surface treatment layer, and an end portion of the first metal layer is positioned closer to a center side of the pad than the end portion of the second metal layer is to form a gap between the end portion of the first metal layer and the surface treatment layer.