A circuit board according to an embodiment includes an insulating layer including a first via hole; a first via disposed in the first via hole of the insulating layer; wherein the first via includes: a first via part disposed in a first region of the first via hole; and a second via part disposed in a second region other than the first region of the first via hole; wherein the second region is a central region of the first via hole, and the first region is an outer region surrounding the second region; wherein the first via part and the second via part includes: a first surface in contact with each other; and a second surface other than the first surface exposed on the insulating layer; wherein the first surface has a first surface roughness; wherein the second surface has a second surface roughness different from the first surface roughness.

A method for manufacturing a flexible circuit board capable of transmitting high frequency signals with reduced attenuation includes providing an inner wiring board including a first conductive wiring layer and a first substrate layer, the first conductive wiring layer including a signal line and two ground lines on both sides of the signal line, the first substrate layer covering a side of the first conductive wiring layer and defining first through holes which expose the signal line; providing two copper clad laminates including a second substrate layer and a copper foil, the second substrate layer having second through hole aligned with the first through holes; laminating the two copper clad laminates onto two sides of the inner wiring board via two adhesive layers, each adhesive layer defining third through holes aligned with the first and second through holes; and forming a second conductive wiring layer from the copper foil.

A printed circuit board includes a first insulating layer having a through hole, and a via disposed to fill the through hole and to be extended to at least one surface of the first insulating layer, wherein the via includes a plating layer having an inner wall part disposed on an inner wall of the through hole and a land part extended from the inner wall part and disposed on the at least one surface of the first insulating layer, and a metal paste layer including metal particles, and filled in the rest of the through hole and disposed on the plating layer.

The power conversion device includes: a main circuit having first and second wiring layers formed respectively on both surfaces of a base board, mounted parts mounted on the first and second wiring layers, and first and second GND layers formed respectively, between external- and internal-layer portions of the base board and in regions corresponding to the mounted parts each being a mounted part which forms a circuit other than a circuit having an inductance component as a lumped constant, and to the first and second wiring layers; and a cooler attached to the base board by means of fixing screws through a first through-hole created in an end portion of the board; wherein the first and second GND layers are each formed so that creepage distance is created around a second through-hole in which a lead insertion part that mutually connects the first and second wiring layers is inserted.

A printed circuit board stack structure includes a first printed circuit board, a second printed circuit board, and a filling glue layer. The first printed circuit board has at least one overflow groove, and includes first pads and a retaining wall surrounding the first pads. The second printed circuit board is disposed on the first printed circuit board, and includes second pads and conductive pillars located on some of the second pads. The conductive pillars are respectively connected to some of the first pads to electrically connect the second printed circuit board to the first printed circuit board. The filling glue layer fills between the first and the second printed circuit boards, and covers the first pads, the second pads, and the conductive pillars. The retaining wall blocks the filling glue layer so that a portion of the filling glue layer is accommodated in the overflow groove.

The present invention provides a method for detecting and adjusting failed back-drills in PCBs in the process of fabricating a PCB so that the failed back-drill can be screened out or repaired. This is accomplished, by after detecting poor back drills in a PCB, measuring the actual thickness of each PCB board. Next, the measured actual thickness of each PCB board is compared with .the theoretical thickness of each PCB board. The back drill depth for each area of the PCB board is then adjusted for its theoretical thickness and percent variation from the measured thickness.to adjust the poor back drill.

An electromagnetic wave transmission board proofed against internal signal leakage includes an inner plate, a first outer plate, a second outer plate, a first plate bump, a first conductive bump, a second plate bump, and a second conductive bump. The inner plate defines a first through hole with a plated metal layer on the hole wall. The first and second plated bumps are disposed between the first outer and inner plates. The second plate bump and the second conductive bump are disposed between the second outer plate and the inner plate. The plate metal layer, the first plate bump, the first conductive bump, the first outer plate, the second outer plate, the second conductive bump, and the second plated bump jointly form an air-filled chamber. A method for manufacturing the electromagnetic wave transmission board is also provided.

Embodiments of the disclosure provide a via structure, a method for preparing the same and a method for regulating impedance of a via structure. The via structure includes a first via, a second via and a first connecting through hole; and a first metal layer a the second metal layer. The first connecting through hole is located between the first via and the second via, and covers part of the first via and part of the second via. The first metal layer and the second metal layer are respectively located in the first via and the second via. The first metal layer and the second metal layer respectively cover a sidewall of the first via and a sidewall of the second via. The first metal layer is separated from the second metal layer through the first connecting through hole.

The present disclosure relates to systems and methods using thermal vias to increase the current-carrying capacity of conductive traces on a multilayered printed circuit board (PCB). In various embodiments, parameters associated with vias may be selected to control various electrical and thermal properties of the conductive trace. Such parameters include the via diameter, a plating thickness, a number of vias, a placement of the vias, an amount of conductive material to be added or removed from the conductive trace, a change in the resistance of the conductive trace, a change in a fusing measurement of the conductive trace, and the like.

An circuit board assembly includes a first circuit board, a second circuit board stacked with the first circuit board, and a connection plate connected between the first circuit board and the second circuit board. The connection plate includes a signal transmission part and at least one ground part at a spacing to the signal transmission part. The ground part can be used as a reference ground for a signal transmitted by the signal transmission part, so that the characteristic impedance of the signal transmission part is controllable, and the signal transmitted by the signal transmission part has strong continuity, thereby maintaining good matching performance and reducing an insertion loss caused by characteristic impedance mismatch.