A flexible substrate has an insulating base member and a conductive layer that is formed on the base member and includes an electrical connecting portion fixed to a component and electrically connected to the component, and the flexible substrate includes: a main portion on which the electrical connecting portion is formed; and a protruding portion provided so as to protrude from a portion of the main portion in which the electrical connecting portion is formed, wherein the main portion is bent along a first bending line extending in a first direction, and wherein the protruding portion can be bent along a second bending line extending in a second direction intersecting the first direction and is adapted to reduce stress occurring at the electrical connecting portion by the protruding portion being bent along the second bending line.

The present disclosure provides circuits and methods for fabricating circuits. A circuit may include an insulator having a first surface, a second surface, a periphery, a first subset of circuit elements disposed on the first surface, a second subset of circuit elements disposed on the second surface, and at least one conductive sidewall disposed on the periphery, wherein the conductive sidewall electrically couples the first subset of circuit elements to the second subset of circuit elements.

A printed circuit board has multiple stacked layers laminated together. A through hole is formed through the laminated stack, and plating is applied to the side walls of the though hole, thereby forming a plated through hole. Second through holes are then formed through the laminated stack, where each second through hole overlaps an edge of the plated through hole. By aligning the second through holes at the edge of the plated through hole, the plating of the plated through hole coincident with each second through hole is removed, thereby separating the plated through hole into two separate circuit paths. Forming second through holes in this manner effectively splits the circuit path of the plated through hole into multiple separate circuit paths, which increases the circuit density of the printed circuit board.

One embodiment provides a circuit board having a substrate and an electrode portion which is provided on the substrate. The electrode portion includes: a quadrangular land which is provided on a front surface of the substrate; a solder layer which is laminated on the whole of a front surface of the land; and a pad which is joined to a front surface of the solder layer. When the electrode portion is seen from thereabove, an outer circumferential line of the pad touches each of four sides of the land. Exposed portions where the solder layer is exposed are formed individually at four corners of a front surface of the electrode portion. And, the exposed portions are formed to have the same shape.

A passive device packaging structure embedded in a glass medium according to an embodiment of the present disclosures includes a glass substrate and at least one capacitor embedded in the glass substrate. The capacitor includes an upper electrode, a dielectric layer, and a lower electrode. The glass substrate is provided on its upper surface with a cavity, the dielectric layer covers a surface of the cavity and has an area larger than that of the cavity. The upper electrode is provided on the dielectric layer. The dielectric layer and the lower electrode are connected by a metal via pillar passing through the glass substrate.

A support structure located at a bottom of a ball grid array (BGA) is provided. The support structure includes a printed circuit board (PCB) having first positioning pin holes, an interface plate having second positioning pin holes which correspond to the first positioning pin holes arranged on the PCB, a support film arranged on the PCB and having support portions, and positioning components penetrating the first positioning pin holes and the second positioning pin holes corresponding to the first positioning pin holes to assemble the support film on the PCB and the interface plate.

A wiring substrate includes a first conductor layer including wirings, an interlayer insulating layer formed on and covering the first conductor layer, a wiring layer formed in the interlayer insulating layer and including wirings, a second conductor layer formed on the interlayer insulating layer and including wirings, and a via conductor formed in the interlayer insulating layer such that the via conductor is penetrating through the interlayer insulating layer and connecting the first and second conductor layers. The interlayer insulating layer includes first and second insulating layers such that the wiring layer is formed on a surface of the first insulating layer, and the wiring layer is formed such that an aspect ratio of the wirings in the wiring layer is in the range of 2.0 to 6.0 and that aspect ratios of the wirings in the first and second conductor layers are in the range of 1.0 to 2.0.

Back drilling vias of a PCB, including: identifying a particular diameter of a particular via of multiple vias of the PCB; back drilling of the particular via with a first drill bit having a first diameter, the first diameter a first percentage greater than the particular diameter of the particular via; determining whether the first diameter of the first drill bit is a threshold percentage greater than the particular diameter of the particular via; determining that the first diameter of the first drill bit is less than the threshold percentage greater than the particular diameter of the particular via, and in response: back drilling of the particular via with a second drill bit having a second diameter, the second diameter a second percentage greater than the particular diameter of the particular via, the second diameter greater than the first diameter.

A high-frequency device includes: a circuit substrate including dielectric layers that are stacked, wiring patterns located on at least one of the dielectric layers, and a passive element formed of at least one of the wiring patterns, the circuit substrate having a first surface that is a surface of an outermost dielectric layer in a stacking direction of the dielectric layers; a terminal for connecting the high-frequency device to an external circuit, the terminal being located on the first surface and electrically connected to the passive element through a first path in the circuit substrate; and an acoustic wave element located on the first surface and electrically connected to the passive element through a second path in the circuit substrate.

An opto-electric hybrid board includes: an electric circuit board including an insulation layer haying front arid back surfaces, arid electrical interconnect lines formed on the front surface of the insulation layer; and an optical waveguide having a substantially rectangular shape as seen in plan view and provided on the back surface of the insulation layer of the electric circuit board, with a metal layer therebetween. The optical waveguide has at least one end portion disposed in overlapping relation with the metal layer. The at least one end portion of the optical waveguide has corner portions. Each of the corner portions is radiused to have an arcuate shape or has a polygonal shape produced by arranging a plurality of obtuse-angled portions in a substantially arcuate configuration.