A wiring circuit board includes a metal support layer, a base insulating layer disposed on one side in a thickness direction of the metal support layer, and a conductive layer disposed on one side in the thickness direction of the base insulating layer, and including a first terminal and a ground lead residual portion electrically connected to the first terminal. The base insulating layer has a through hole penetrating in the thickness direction. The ground lead residual portion has an opening continuous so as to surround the through hole.

A circuit substrate comprising, in the following stacked order, a resin base material 1 having a dielectric loss tangent of 0.015 or lower, a polyaniline layer 2 comprising a substituted or unsubstituted polyaniline, and a metal layer 3, wherein the metal layer 3 has a surface roughness Rz.sub.JIS of 0.5 μm or less at the surface on the side of the polyaniline layer 2.

There is provided a method for manufacturing a printed wiring board that effectively suppresses pattern failure and is also excellent in fine circuit forming properties. This method includes: providing an insulating substrate including a roughened surface; performing electroless plating on the roughened surface of the insulating substrate to form an electroless plating layer less than 1.0 μm thick having a surface having an arithmetic mean waviness Wa of 0.10 μm or more and 0.25 μm or less as measured in accordance with JIS B0601-2001 and a kurtosis Sku of 2.0 or more and 3.5 or less as measured in accordance with ISO 25178; laminating a photoresist on the surface of the electroless plating layer; performing exposure and development to form a resist pattern; applying electroplating to the electroless plating layer; stripping the resist pattern; and etching away an unnecessary portion of the electroless plating layer to form a wiring pattern.

A method for forming a thermal and electrical path in a PCB may include forming a first removable layer over a top surface of a PCB and a second removable layer over a bottom surface of the PCB. The method may also include milling or laser drilling the PCB from the top surface to form a first cavity extending into the PCB, plating the first side panel plating the first side with a second metal to partially fill the first cavity; and milling or laser drilling from the bottom surface to form a second cavity extending into the PCB, the first cavity in a thermal communication and/or an electrical communication with the second cavity. The method may also include panel plating the first side with a second metal to fill the first cavity and the second side with the second metal to fill the second cavity, and removing the first and second removable layers from the PCB to form the PCB with a thermal and/or an electrical path comprising the first cavity and the second cavity filled with the second metal.

A method of forming a multi-layer circuit on a curved substrate includes forming, by a laser direct structuring process, a first layer of the multi-layer circuit on a first surface of the curved substrate. The method includes applying a first layer of paint to the first layer of the multi-layer circuit. The method includes forming, by the laser direct structuring process, a second layer of the multi-layer circuit on the first layer of the paint and electrically coupled to the first layer of the multi-layer circuit. The method includes applying a second layer of paint over the second layer of the multi-layer circuit and forming, by the laser direct structuring process, a third layer of the multi-layer circuit on the second layer of the paint and electrically coupled to the second layer of the multi-layer circuit.

A circuit structure that comprises a substrate and one or more conductive elements disposed on the substrate is provided. The substrate comprises a polymer composition that comprises an electrically conductive filler distributed within a polymer matrix. The polymer matrix contains at least one thermoplastic high performance polymer having a deflection temperature under load of about 40° C. or more as determined in accordance with ISO 75-2:2013 at a load of 1.8 MPa, and the polymer composition exhibits a dielectric constant of about 4 or more and a dissipation factor of about 0.3 or less, as determined at a frequency of 2 GHz.

A flexible printed circuit board (FPCB) including a pattern circuit layer. The pattern circuit layer has a pattern fuse embedded therein, and the pattern fuse includes a first conductive wire made of a metal and having a spiral structure, and a second conductive wire made of a metal and having a spiral structure. The first conductive wire and the second conductive wire have a double helix structure.

Provided is a method for manufacturing a circuit board including: (a) preparing a mixture of a metal powder, an anti-sintering agent, and an activator; (b) immersing a dielectric substrate in the mixture; (c) forming a metal-containing layer on the surface of the dielectric substrate by heating the mixture under an inert atmosphere or under a reducing atmosphere; (d) forming a first metal layer on the metal-containing layer by electroless plating and forming a second metal layer thereon by electroplating; and (e) forming a metal pattern on the dielectric substrate, wherein the first metal layer includes Cu, Ni, Co, Au, Pd, or an alloy thereof, the second metal layer includes Cu, Ni, Fe, Co, Cr, Zn, Au, Ag, Pt, Pd, Rh, or an alloy thereof, and the method further includes performing heat treatment at least once after step (c).

A circuit board has a dielectric core, a foil top surface, and a thin foil bottom surface with a foil backing of sufficient thickness to absorb heat from a laser drilling operation to prevent the penetration of the thin foil bottom surface during laser drilling. A sequence of steps including a laser drilling step, removing the foil backing step, electroless plating step, patterned resist step, electroplating step, resist strip step, tin plate step, and copper etch step are performed, which provide dot vias of fine linewidth and resolution.

A printed circuit board includes an insulating layer and a circuit layer disposed on the insulating layer. The circuit layer includes a first circuit pattern and a second circuit pattern. Each of the first and second circuit patterns has a first side surface, a second side surface opposing the first side surface, and a top surface connected to ends of the first and second side surfaces, when viewed in a cross section direction. The first side surface of the first circuit pattern and the first side surface of the second circuit pattern face each other. A height of the first side surface of the first circuit pattern is greater than a height of the second side surface of the first circuit pattern, and a height of the first side surface of the second circuit pattern is greater than a height of the second side surface of the second circuit pattern.