A stub of a via formed in a printed circuit board is backdrilled to a predetermined depth. A capacitance probe is positioned within the via. Then the capacitance probe is used to obtain a test capacitance measurement. The test capacitance measurement is compared to a predetermined baseline capacitance measurement. Residual conductive plating material in the backdrilled stub causes the test capacitance measurement to exceed the predetermined baseline capacitance measurement. An indication is made that the predetermined baseline capacitance measurement has been exceeded.

A wiring substrate includes an insulating layer, a stack including wiring layers and photosensitive-resin insulating layers on a first surface of the insulating layer, a wiring layer on a second surface of the insulating layer, having a lower wiring density than the wiring layers, a metal core plate buried in the insulating layer and positioned on the stack side with respect to the center of the insulating layer in its thickness direction, and a via wiring buried in the insulating layer to have a first end face exposed at the first surface and joined to the lowermost one of the wiring layers, and a second end face joined to the metal core plate. The first surface and the first end face are substantially flush with each other. The wiring layers include a signal line, and a ground line concentrically formed around the signal line, with a predetermined interval therebetween.

Systems and methods for grooved vias are described. For example, a method may include: drilling a via hole in a Printed Circuit Board (PCB), where the PCB comprises a first layer having a first trace and a second layer having a second trace, the via hole includes a first portion between the first layer and the second layer and a second portion between the second layer and a bottom surface of the PCB, and the via hole is configured to couple the first trace to the second trace through the first portion; after drilling the via hole, creating a rough internal surface in at least the second portion of the via hole that is configured to reduce a resonance of a signal transmitted from the first trace to the second trace; and forming a via by filling the first and second portions of the via hole with conductive material.

A trace embedded probe device includes a circuit board including an insulating layer unit whose upper surface has first recesses and a second recess located therebetween, grounding traces and a signal trace whose trace main bodies are disposed in the recesses respectively and flush in elevation with the upper surface, and a grounding layer disposed on a lower surface of the insulating layer unit and connected with the grounding traces by conductive vias penetrating through the first recesses and the lower surface and provided therein with conductive layers. The trace main bodies, grounding layer and conductive layers are made of a same metal material. Probes are disposed on the grounding and signal traces respectively. The probe device is easy in control of distance, width, thickness and surface roughness of the traces, and beneficial to achieve the requirements of thin copper traces, fine pitch and high frequency testing.

A printed circuit board includes a plurality of layers including attachment layers and routing layers; first and second signal vias forming a differential signal pair, the first and second signal vias extending through the attachment layers and connecting to respective signal traces on a breakout layer of the routing layers; an antipad of a first type around and between the first and second signal vias in one or more of the attachment layers; and antipads of a second type around the first and second signal vias in at least one routing layer adjacent to the breakout layer.

Provided are a circuit board, an apparatus and a method for forming a via hole structure. A via hole structure formed on a main body (10) of a circuit board includes a hole (12) enclosed by a conductive layer in the main body (10), the conductive layer constitutes a wall (11) of the hole (12), and a dielectric filling layer (13), which has a dielectric constant smaller than that of the main body (10), is disposed between at least a portion of the wall (11) of the hole (12) and the main body (10), so that the parasitic capacitance of a via hole is decreased, and the impedance of the via hole is increased to become closer to the impedance of a transmission line, thereby effectively improving impedance continuity of a system link.

A multi layer interconnecting substrate has at least two spaced apart metal layers with a conductive pad on each one of the metal layers. Two different types of insulating layers are placed between the metal layers. The placement is such that one of the two different types of insulating layers is placed between the conductive pads and the other type of insulating layer is placed between the two spaced apart metal layers.

An optimized ground (GND) network connection is provided between a Quad Small Form-factor Pluggable (QSFP) connector and a printed circuit board (PCB). The optimized GND network creates a “GND Island” around the signal pads by adding GND cage around the signal pads (at the empty corridor and in front of QSFP pads) and GND TH (ground through hole) vias from both sides of signal pads (at the empty corridor and in front of QSFP pads).

The present invention relates to a microwave signal transition component (1) having a first signal conductor side (2) and a second signal conductor side (3). The signal transition component (1) is arranged for transfer of microwave signals from the first signal conductor side (2) to the second signal conductor side (3). The transfer component (1) comprises at least one, at least partly circumferentially running, electrically conducting frame (4), a dielectric filling (5) positioned at least partly within said conducting frame (4), at least one filling aperture (6; 6a, 6b) miming through the dielectric filling, and, for each filling aperture (6; 6a, 6b), an electrically conducting connection (7; 7a, 7b) that at least partly is positioned within said filling aperture (6; 6a, 6b). The present invention also relates to a method for manufacturing a microwave signal transition component according to the above.

A multi-layer circuit structure includes a differential transmission line pair and at least one conductive pattern. The differential transmission line pair includes first and second transmission lines disposed side by side. Each of the first and second transmission lines includes first and second segments connected to each other. An spacing between the two first segments is non-fixed, and an spacing between the two second segments is fixed. A first zone is located between the two first segments, a second zone is opposite to the first zone and located outside the first segment of the first transmission line, and a third zone is opposite to the first zone and located outside the first segment of the second transmission line. The conductive pattern is coplanar with the differential transmission line pair and disposed on at least one of the first, second and third zones. The conductive pattern is electrically connected to a reference potential and electrically insulated from the differential transmission line pair.