A high-frequency circuit includes a first electric conductor layer, a first dielectric layer, a circuit layer, a second dielectric layer, a second electric conductor layer arranged in this order, and the circuit layer includes a ground pattern and a transmission line of a high-frequency signal. An electromagnetic wave shield is disposed around the transmission line. The electromagnetic wave shield includes a ground electric conductor on inner surfaces of a plurality of holes extending through the first dielectric layer, the ground pattern, the second dielectric layer, the first electric conductor layer, and the second electric conductor layer. The plurality of holes are a plurality of elongated holes provided at an interval in a direction in which the transmission line is surrounded. In each of the plurality of elongated holes, a longitudinal dimension in the direction in which the transmission line is surrounded is larger than a width dimension.

The invention discloses a circuit board enhancing structure and a manufacture method thereof. The method includes the following steps: providing a substrate; forming a first circuit on the substrate; forming a first dielectric layer enclosing the first circuit on the substrate; forming a first opening on the first dielectric layer; forming a first pattern photoresist layer on the first dielectric layer to divide a surface of the first dielectric layer as a first structure enhancing area and a second circuit area, wherein the first opening is disposed in the first structure enhancing area; forming a second circuit in the second circuit area and a first enhancing structure in the first opening, wherein the first enhancing structure protrudes from the first opening; removing the first pattern photoresist layer; and forming a second dielectric layer enclosing the second circuit and the first enhancing structure on the first dielectric layer.

A flexible circuit board includes liquid crystal polymer (LCP) layers and metal layers including circuit routes. Each of the LCP layers includes via structures. The metal layers and the LCP layers are alternatively stacked to form a multi-layer structure. Adjacent metal layers are electrically connected through the via structures. Some via structures of different LCP layers are substantially aligned with one another to form a stack of via structures. Each of the via structures includes openings filled with conductive material. The size of the opening fulfils the following equation: Vb≥cos(Bh/Vh)*Vt/k*2, where Vb is a diameter of a smaller aperture, Vt is a diameter of a bigger aperture, Vh is a combined thickness of a LCP layer and a metal layer, Bh is a thickness of a LCP layer and k is a tensile modulus.

A method for manufacturing a circuit board is disclosed. An inner wiring base board with a first opening is provided. A base board is fixed in the first opening, and a first wiring base board and a second wiring base board are pressed on opposite surfaces of the inner wiring base board. The base board is made of ceramic and has a high light reflectivity of 92% to 97%. A first conductor layer and a second conductor layer are formed on opposite surfaces of the laminated structure. The first conductor layer includes a plurality of connecting pads on the base board. A solder mask is formed on an outer side of the first conductor layer, the solder mask has a high light reflectivity of 92% to 95%, and the base board is exposed outside the solder mask.

A printed circuit board includes a plurality of layers including attachment layers and routing layers; and via patterns formed in the plurality of layers, each of the via patterns including first and second signal vias forming a differential signal pair, the first and second signal vias extending through at least the attachment layers; ground vias extending through at least the attachment layers, the ground vias including ground conductors; and shadow vias located adjacent to each of the first and second signal vias, wherein the shadow vias are free of conductive material in the attachment layers. The printed circuit board may further include slot vias extending through the attachment layers and located between via patterns.

A printed circuit board includes: a first insulating layer; a first metal layer disposed on one surface of the first insulating layer; a second metal layer disposed on the other surface facing the one surface of the first insulating layer; a via penetrating through the first insulating layer to connect the first and second metal layers to each other; and a heterogeneous metal region disposed in at least one of an area in which the via is adjacent to the first insulating layer and an area in which the via is adjacent to the first metal layer, and including a material different from that of the via, wherein the heterogeneous metal region includes at least one of nickel (Ni), silicon (Si), and titanium (Ti).

A wiring board includes: first and second insulating layers; a first wiring conductor layer located between the first and second insulating layers and including a first via land; a second wiring conductor layer located on the second insulating layer and including a second via land; a via hole penetrating from the upper to lower surfaces of the second insulating layer; and a via conductor located in the via hole and electrically connecting the first second via lands. The via conductor is located on the inner surface of the via hole and on the first via land via a first base layer containing nichrome and a second base layer located on the upper surface of the first base layer and containing the same metal as the via conductor. An alloy layer containing tin and nichrome is located between the first via land and the first base layer.

A circuit board with anti-corrosion properties, a method for manufacturing the circuit board, and an electronic device are provided. The circuit board includes a circuit substrate, a first protective layer, and a second protective layer. The circuit substrate includes a base layer and an outer wiring layer formed on the base layer. The circuit substrate further defines a via hole connected to the outer wiring layer. The first protective layer is formed on the outer wiring layer and an inner sidewall of the via hole, and is made of a white oil. The second protective layer is formed on the first protective layer.

A circuit board includes a metal substrate, a resin layer, an insulating layer, and a first conductive structure. The metal substrate has a first through hole, and the first through hole has a first width. A portion of the resin layer is disposed in the first through hole. The resin layer has a second through hole. The second through hole has a second width. The insulating layer is disposed on at least one surface of the metal substrate, and a portion of the insulating layer contacts the resin layer. The first conductive structure is disposed in the second through hole. The first conductive structure penetrates through the metal substrate. The first width is greater than the second width. A manufacturing method of the circuit board is also provided.

A wiring circuit board includes a porous insulating layer, and a first conductive layer sequentially toward one side in the thickness direction. The first conductive layer includes a first signal wire and first ground wires. Each of the first ground wires is thicker than the first signal wire.