A circuit may be configured to reduce electrical signal degradation. The circuit may include a first trace and a second trace that may be broadside coupled between a first ground plane and a second ground plane. The first and second traces may be configured to carry first and second signals, respectively, of a differential signal. The circuit may also include a first dielectric material disposed between the first trace and the second trace. Further, the circuit may include a second dielectric material disposed between the first trace and the first ground plane and disposed between the second trace and the second ground plane. A difference between a first dielectric constant of the first dielectric material and a second dielectric constant of the second dielectric material may suppress a mode conversion of the differential signal from a differential mode to a common mode.

A package includes a conductive pad, with a plurality of openings penetrating through the conductive pad. A dielectric layer encircles the conductive pad. The dielectric layer has portions filling the plurality of openings. An Under-Bump Metallurgy (UBM) includes a via portion extending into the dielectric layer to contact the conductive pad. A solder region is overlying and contacting the UBM. An integrated passive device is bonded to the UBM through the solder region.

A wiring substrate includes a core layer having a penetrating hole, a first insulating layer disposed on a first surface of the core layer and having a first opening at a position of the penetrating hole, the first insulating layer containing no filler, a penetrating electrode disposed in the penetrating hole and in the first opening, and a first wiring layer laminated both on the first insulating layer at a first surface thereof facing away from the core layer and on an end face of the penetrating electrode, wherein the first surface of the first insulating layer and the end face of the penetrating electrode are planarized.

In an example, a process for reversibly bonding a conformal coating to a dry film solder mask (DFSM) material is disclosed. The process includes applying a first conformal coating material to a DFSM material. The first conformal coating material includes a first functional group, and the DFSM material includes a second functional group that is different from the first functional group. The process also includes reversibly bonding the first conformal coating material to the DFSM material via a chemical reaction of the first functional group and the second functional group.

In an example, a process for reversibly bonding a conformal coating to a dry film solder mask (DFSM) material is disclosed. The process includes applying a first conformal coating material to a DFSM material. The first conformal coating material includes a first functional group, and the DFSM material includes a second functional group that is different from the first functional group. The process also includes reversibly bonding the first conformal coating material to the DFSM material via a chemical reaction of the first functional group and the second functional group.

A circuit may be configured to reduce electrical signal degradation. The circuit may include a first trace and a second trace that may be broadside coupled between a first ground plane and a second ground plane. The first and second traces may be configured to carry first and second signals, respectively, of a differential signal. The circuit may also include a first dielectric material disposed between the first trace and the second trace. Further, the circuit may include a second dielectric material disposed between the first trace and the first ground plane and disposed between the second trace and the second ground plane. A difference between a first dielectric constant of the first dielectric material and a second dielectric constant of the second dielectric material may suppress a mode conversion of the differential signal from a differential mode to a common mode.

The resin composition according to an exemplary embodiment of the present application comprises: an epoxy-based resin; a curing agent comprising a cyanate ester-based resin and a phenolic resin; inorganic particles comprising silica particles; and a curing accelerator, the weight ratio of the cyanate ester-based resin:the phenolic resin is 95:5 to 40:60, and the curing accelerator comprises both an imidazole-based compound and a metal-based compound.

A provided circuit board includes an embedded capacitor, a substrate, and an insulating layer. The embedded capacitor includes a dielectric layer, a first electrode and a second electrode. The dielectric layer has a first side surface, a second side surface adjacent to the first side surface, a third side surface opposite to the first side surface, and a fourth side surface opposite to the second side surface. The first and second electrodes respectively cover the first and third side surfaces. The substrate surrounds the embedded capacitor and is physically connected to the second and fourth side surfaces. The first electrode is between the first side surface and a sidewall of the substrate. The insulating layer covers the embedded capacitor and the substrate and extends from an upper surface to a lower surface of the substrate along the first electrode and the sidewall of the substrate.

A circuit board structure includes a core, a wiring layer and a buried passive component. The wiring layer and the buried passive component are disposed on the core, and the buried passive component is electrically connected to the wiring layer. The buried passive component includes a first spiral metal layer, a second spiral metal layer and a dielectric interlayer. The first spiral metal layer is intertwined with the second spiral metal layer. The dielectric interlayer is disposed between the first spiral metal layer and the second spiral metal layer. The first spiral metal layer and the second spiral metal layer are spaced apart by the dielectric interlayer at least in the core.

In an example, a process for reversibly bonding a conformal coating to a dry film solder mask (DFSM) material is disclosed. The process includes applying a first conformal coating material to a DFSM material. The first conformal coating material includes a first functional group, and the DFSM material includes a second functional group that is different from the first functional group. The process also includes reversibly bonding the first conformal coating material to the DFSM material via a chemical reaction of the first functional group and the second functional group.