A metal-clad laminate includes an insulating layer, and a metal foil in contact with at least one surface of the insulating layer, in which the insulating layer contains a cured product of a resin composition containing a polyphenylene ether compound, and the metal foil is a metal foil in which a first nickel element amount, on a surface on a side in contact with the insulating layer, measured by X-ray photoelectron spectroscopy is 4.5 at % or less with respect to a total element amount measured by X-ray photoelectron spectroscopy, and a second nickel element amount, on a surface on a side in contact with the insulating layer when the surface is sputtered for 1 minute at a speed of 3 nm/min in terms of SiO2, measured by X-ray photoelectron spectroscopy is 4.5 at % or less with respect to a total element amount measured by X-ray photoelectron spectroscopy.

Provided are flexible hybrid interconnect circuits and methods of forming thereof. A flexible hybrid interconnect circuit comprises multiple conductive layers, stacked and spaced apart along the thickness of the circuit. Each conductive layer comprises one or more conductive elements, one of which is operable as a high frequency (HF) signal line. Other conductive elements, in the same and other conductive layers, form an electromagnetic shield around the HF signal line. Some conductive elements in the same circuit are used for electrical power transmission. All conductive elements are supported by one or more inner dielectric layers and enclosed by outer dielectric layers. The overall stack is thin and flexible and may be conformally attached to a non-planar surface. Each conductive layer may be formed by patterning the same metallic sheet. Multiple pattern sheets are laminated together with inner and outer dielectric layers to form a flexible hybrid interconnect circuit.

A circuit board includes a conductive plate held by a holding member, an insulation sheet provided on one side of the conductive plate, and a circuit component that is placed on the conductive plate and that has a terminal, and a void portion is formed in the insulation sheet, and a conductive material for electrically connecting the conductive plate and the terminal to each other is applied to a region that is exposed from the void portion on the one side of the conductive plate.

A resin composition of the present invention contains: a maleimide compound (A) having a maleimide functional group equivalent of 300 g/eq. or more, and a transmittance of 1% or more at a wavelength of 405 nm (h-line); a maleimide compound (B) having a maleimide functional group equivalent of less than 300 g/eq.; and a photo initiator (C) having an absorbance of 0.1 or more at a wavelength of 405 nm (h-line).

A stretchable laminate to be fixed to a fabric includes a stretchable circuit board including a stretchable insulating layer having an elongation rate of 10% or more, a fabric base material, and an adhesive layer that bonds the stretchable circuit board and the fabric base material together.

A resin composition is provided and includes (A) a modified polyphenylene ether compound terminal-modified with a substituent having a carbon-carbon unsaturated double bond, (B) a maleimide compound containing no phenylmaleimide group and having a hydrocarbon group having 10 or more carbon atoms in the molecule thereof, and (C) at least one selected from a maleimide compound containing a phenylmaleimide group and a maleimide compound having an aliphatic hydrocarbon group having 9 or less carbon atoms in the molecule thereof, in which the content ratio of the component (A) to the component (B) is (A):(B)=20:80 to 90:10 in mass ratio.

A resin composition contains an epoxy compound and a curing agent. The epoxy compound includes a phosphorus-containing epoxy compound having a phosphorus atom in its molecule. The curing agent includes a phosphorus-containing acid anhydride having a phosphorus atom and an acid anhydride group in its molecule.

There is provided a resin composition that can greatly improve voltage endurance while ensuring high capacitance and excellent circuit adhesion, when used as the dielectric layer of a capacitor. This resin composition includes a binder component including bisphenol S, an epoxy resin curing agent having a phenolic hydroxyl group, and an epoxy resin; and a dielectric filler.

A dielectric property-lowering agent is composed of a specific epoxy-modified silicone resin having a low relative permittivity and a low dielectric loss tangent, and has an ionic species content of less than 0.001 wt %.

To provide an epoxy resin composition that exhibits excellent low dielectric properties and that is excellent in copper foil peel strength and interlayer cohesion strength in a printed-wiring board application, a phenol resin and an epoxy resin for providing the composition, and a method for producing such a resin. A phenol resin containing a dicyclopentenyl group and represented by the following general formula (1): wherein each R.sup.1 independently represents a hydrocarbon group having 1 to 8 carbon atoms; each R.sup.2 independently represents a hydrogen atom or a dicyclopentenyl group, and at least one R.sup.2 is a dicyclopentenyl group; i is an integer of 0 to 2; and n represents the number of repetitions and an average value thereof is a number of 10 to 10.

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