Provided herein are embodiments of a PWB circuit construction material, and its use in flexible PWB circuits. The PWB circuit construction material is made up of temperature resistant fabric bonded to a metal substrate using a bonding agent. The temperature resistant material may include synthetic aromatic polyamide fibers. The fabric may be used as a reinforcement for the standard PWB construction materials for flexible PWB circuits and as a standalone piece that is bonded as a hinge at rigid portions of a rigid or rigid-flexible PWB circuit to reduce the thermal effects.

A method to remove slugs from a circuitry pattern on the fly during the fabrication of a flexible printed circuit, the method includes applying a coverlay reel-to-reel onto one side of the metal foil on the fly and applying a sacrificial liner reel-to-reel onto another side of the metal foil on the fly. Then, after the slugs and circuitry patterns are created from laser ablation, the slug can be removed by applying compressed air to the slugs and/or peeling off the sacrificial liner from the circuitry pattern reel-to-reel.

To provide a circuit board that has excellent smoothness and capable of reducing a transmission loss of a high-frequency electrical signal.

The circuit board according to the present invention includes a wiring portion and a non-wiring portion, the wiring portion having a metal layer and a resin layer, the non-wiring portion having a resin layer, the resin layer at a frequency 10 GHz having a relative permittivity of from 2 to 3 at 23 C., and the circuit board satisfying a relationship: (AB)/B0.1 wherein A is the maximum value of the thickness in the wiring portion (m) and B is the minimum value of the thickness in the non-wiring portion (m).

A wiring board includes core substrate, a first build-up layer on first surface of the substrate and including conductive and insulating resin layers, and a second build-up layer on second surface of the substrate and including conductive and insulating resin layers. The first build-up is formed such that each conductive layer includes a metal foil layer and a plating layer on the foil layer and the foil layer of a conductive layer on an outermost resin layer has thickness greater than thickness of the foil layer of each conductive layer on a non-outermost resin layer, and the second build-up is formed such that each conductive layer includes a metal foil layer and a plating layer on the foil layer and the foil layer of a conductive layer on an outermost resin layer has thickness greater than thickness of the foil layer of each conductive layer on a non-outermost resin layer.

A resin composition comprising at least an organic resin, wherein physical property parameters specified by a storage modulus at a predetermined temperature and a glass transition temperature satisfy their respective predetermined ranges.

A polyimide laminated film containing a thermoplastic polyimide layer that includes a block (A) having a storage elastic modulus of 0.15 GPa or more at 380 C. and a block (B) having a storage elastic modulus of 0.10 GPa or less at 380 C. is used as a polyimide laminated film that has high peel strength and can suppress occurrence of a crack in an alkaline environment.

A multilayer board insulating sheet contains a reducing agent.

A wiring board includes core substrate, a first build-up layer on first surface of the substrate and including conductive and insulating resin layers, and a second build-up layer on second surface of the substrate and including conductive and insulating resin layers. The first build-up is formed such that each conductive layer includes a metal foil layer and a plating layer on the foil layer and the foil layer of a conductive layer on an outermost resin layer has thickness greater than thickness of the foil layer of a conductive layer on a non-outermost resin layer, and the second build-up is formed such that each conductive layer includes a metal foil layer and a plating layer on the foil layer and the foil layer of a conductive layer on an outermost resin layer has thickness greater than thickness of the foil layer of a conductive layer on a non-outermost resin layer.

A resin-clad metal foil which enables a reduction in fluidity of a resin during molding and a reduction in extrusion of the resin while maintaining good adhesiveness, bendability, thermal resistance, and circuit filling property. A first insulating layer includes a polyimide resin layer, a polyamideimide resin layer, a liquid crystal polymer resin layer, a fluororesin layer, or a polyphenylene ether resin layer and a second insulating layer includes a polyolefin resin layer in a semi-cured state are disposed in this order on a metal foil. The polyolefin resin layer contains a component representing a polyolefin-based elastomer and a component representing a thermosetting resin. The percentage by mass of the component in the polyolefin resin layer ranges from 50 wt. % to 95 wt. %.

A component-embedded substrate includes a laminate and first and second components. The laminate includes resin layers each made of thermoplastic that are laminated together. The first and second components are embedded in the laminate. The first component has a length in the lamination direction that is greater than a length of the first component in a first direction orthogonal or substantially orthogonal to the lamination direction. The first and second components are disposed adjacent to each other in the first direction, and are disposed at respective positions overlapping with each other as viewed from the first direction. A distance between the first and second components in the first direction is less than the length of the first component in the lamination direction.