Package to printed circuit board (PCB) transitions are described. In one aspect, a multi-layer PCB includes an external layer having a transition region configured to receive an electrical component and a clear routing region outside of the transition region. The PCB includes first via(s) that extend from the transition region to an inner trace routing layer. The trace routing layer is disposed between the external layer and the second inner trace routing layer. The first inner trace routing layer includes a transition area disposed under the transition region of the external layer, a clear routing area outside of the transition region, and a transmission line that connects a given first via to a second via for a second electrical component. The transmission line includes conductive trace(s) that each have a first width in the transition area and a second width, greater than the first width, in the clear routing area.

A method of manufacturing a circuit substrate includes forming, in an insulating substrate and circuit patterns that are provided on a first surface and a second surface of the insulating substrate, a through-hole penetrating the insulating substrate and the circuit patterns, where the circuit patterns contain Cu as a main component. The method includes filling, in the through-hole, an electrically conductive paste that is a melting-point shift electrically conductive paste including SnBi solder powder, Cu powder, and resin, and forming a protrusion obtained by causing the electrically conductive paste to protrude from the through-hole. The method further includes performing pressure treatment on the protrusion near the through-hole; and performing heat treatment on the insulating substrate whose protrusion is subjected to the pressure treatment and causing the circuit patterns and the electrically conductive paste to be electrically connected with each other.

A wiring board includes: a wiring-board body including a first surface and a second surface opposite to the first surface, and including at least one insulator layer; pads formed at at least one of an internal layer boundary plane and the first surface and the second surface defining a first plane; and via conductors connected to corresponding ones of the pads, and arranged in parallel to extend in a thickness direction of the wiring-board body. Each of first and second ones of the pads adjacent to each other in planar view at the first plane is connected to corresponding ones of the via conductors. The via conductors corresponding to the first pad are arranged differently from the via conductors corresponding to the second pad, in planar view.

A method of manufacturing a circuit substrate including forming, in an insulating substrate and circuit patterns that are provided on a first surface and a second surface of the insulating substrate, a through-hole penetrating the insulating substrate and the circuit patterns, where the circuit patterns contain Cu as a main component. The method including filling, in the through-hole, an electrically conductive paste that is a melting-point shift electrically conductive paste including SnBi solder powder, Cu powder, and resin, and forming a protrusion obtained by causing the electrically conductive paste to protrude from the through-hole. The method further including performing pressure treatment on the protrusion near the through-hole; and performing heat treatment on the insulating substrate whose protrusion is subjected to the pressure treatment and causing the circuit patterns and the electrically conductive paste to be electrically connected with each other.

A multi-layer PCB has conductive vias (134) passing through multiple layers. A layer may have a conductive non-functional feature (710) physically contacting a via but not surrounding the via, to make the PCB more resistant to thermal stresses while, at the same time, reducing the parasitic capacitance compared to a prior art non-functional pad (310n).

A printed circuit board includes: an insulating layer having a via hole formed therein; a single layer metal pad disposed in the insulating layer and having a center portion that is exposed by the via hole, the center portion of the pad having a higher roughness than peripheral portions of the pad; and a via formed in the via hole and connected to the center portion of the pad.

A multi-layer PCB has conductive vias (134) passing through multiple layers. A layer may have a conductive non-functional feature (710) physically contacting a via but not surrounding the via, to make the PCB more resistant to thermal stresses while, at the same time, reducing the parasitic capacitance compared to a prior art non-functional pad (310n).

An electric device is provided. The electric device includes a first housing, a second housing, a touch panel, a flexible printed circuit board, a control chip, and a main circuit board. The touch panel is disposed in the first housing. The flexible printed circuit board includes a substrate, a plurality of first connecting lines, a plurality of second connecting lines and a plurality of third connecting lines. The substrate has a first surface and a second surface. The first connecting lines are connected to a first peripheral line on the first surface. The second connecting lines are connected to a second peripheral line on the first surface. The third connecting lines are connected to a third peripheral line on the second surface, and are arranged from the second surface to the first surface through a plurality of first through holes.

An electronic device may be provided with a transceiver, a substrate, and antennas mounted to the substrate. The transceiver and antennas may convey signals between 10 GHz and 300 GHz. A radio-frequency connector may be mounted to the substrate. A coaxial cable may couple the transceiver to the connector. A stripline in the substrate may couple the connector to the antennas. Impedance matching structures may be embedded in the substrate for matching an impedance of the stripline to an impedance of the coaxial cable. The impedance matching structures may include a fence of conductive vias, landing pads, and a volume of the dielectric substrate defined by the fence of conductive vias and the landing pads. The impedance matching structures may be configured to perform impedance matching over a relatively wide bandwidth that includes the frequency band of operation for the antennas.

Flexible fingers for flexible printed circuits improve the crack resistance of prior art designs. The crack resistance can be improved by encapsulating the trace inside additional layers such that the outer two layers include only the lands of the through-hole, and all other copper is etched away. The crack resistance can also be improved with strategically adding copper on layers other than the trace layer including attaching is to the land of the through-hole as a stub. These two designs can be combined to include a stub trace into a four-layered design.