Provided are a metal-clad laminate, a printed circuit board, and a semiconductor package, wherein the warps therein are effectively suppressed. Specifically the metal-clad laminate comprises a prepreg, wherein the prepreg has a resin composition attached to a fiber base material and satisfies a following formula (1) as well as a Mowing formula (2), provided that in the formulae, a1 represents an average thickness of the resin composition after being cured which is present on one surface of the fiber base material; a2 represents an average thickness of the resin composition after being cured which is present on other surface of the fiber base material; and B represents an average thickness of the fiber base material.
0.12<{(a1+a2)/2}/B  (1)
0.8≤a1/a2≤1.25  (2)

A nitride-based ceramics resin composite body having thermal conductivity, electrical insulation, and adhesion to adherends equal to conventional products, and having improved heat resistance reliability during the reflow process, and a thermal conductive insulating adhesive sheet using the same are provided. A nitride-based ceramics resin composite body in which a thermosetting resin composition is impregnated in a porous nitride-based ceramics sintered body is provided. The thermosetting resin composition includes a specific epoxy resin and a bismaleimide triazine resin, and a water absorption of the thermosetting resin composition in a completely cured state measured in accordance with method A in JIS K7209 (2000) is 1% by mass or less.

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, as well as an active ester resin that provides the epoxy resin composition. An active ester resin having a polyaryloxy unit containing a dicyclopentenyl group and represented by the following formula (1), and a polyarylcarbonyl unit. Here, R.sup.1 represents a hydrocarbon group having 1 to 8 carbon atoms, R.sup.2 represents a hydrogen atom, or formula (1a) or formula (1b), and at least one R.sup.2 is formula (1a) or formula (1b); and n represents a number of repetitions of 1 to 5.

##STR00001##

Provided is a resin composition having excellent low water absorption, as well as a cured product, a prepreg, a metal foil-clad laminate, a resin sheet, and a printed wiring board. The resin composition contains a compound (A) represented by Formula (M1) and a compound (B) containing two or more unsaturated carbon-carbon double bonds, and in Formula (M1), A is a four- to six-membered alicyclic group:

##STR00001##

A metal-clad laminate includes: an insulating layer; and a metal layer stacked on the insulating layer. The insulating layer includes: a first layer; and a second layer interposed between the first layer and the metal layer. The first layer contains a cured product of a first resin composition containing composite particles. The second layer contains a cured product of a second resin composition. The first resin composition contains composite particles, each having a core containing a fluororesin and a shell containing a silicon oxide that coats the core at least partially. The second resin composition may or may not contain composite particles. When the second resin composition contains the composite particles, a ratio of the composite particles in the second resin composition to solid content of the second resin composition is lower than a ratio of the composite particles in the first resin composition to solid content of the first resin composition.

Provided are a surface-treated glass cloth that enables the reliability of a printed wiring board to be improved, a prepreg, and a printed wiring board. In the surface-treated glass cloth, a surface-treated layer contains a silane coupling agent, the amount of carbon attached of an adhering component of the surface-treated layer is in the range of 0.030 to 0.060% by mass, the arithmetic average height of the surface of the adhering component of the surface-treated layer is in the range of 1.0 to 3.0 nm, and the product of the amount of carbon attached of the adhering component and the arithmetic average height of the surface of the adhering component is in the range of 0.060 to 0.100.

Provided is copper foil with a resin layer, the resin layer having excellent adhesion, the copper foil exhibiting low dielectric characteristics, which is suitable for high-frequency applications, the copper foil being capable of exhibiting excellent characteristics of reducing transmission loss. More specifically, a laminate of copper foil and an epoxy resin composition layer is provided, the epoxy resin composition layer being present on at least one surface of the foil, the epoxy resin composition containing an epoxy resin and an acid-modified polyolefin, wherein a test piece composed of the laminate and a prepreg has 90-degree peel strength between the copper foil and the prepreg of 0.6 N/mm or more as measured in accordance with JISC6481, and has a reduction rate of the 90-degree peel strength between the copper foil and the prepreg of 20% or less after immersion of the test piece in boiling water for 2 hours.

A coreless component carrier includes (a) a stack with at least one electrically conductive layer structure and at least one electrically insulating layer structure; and (b) a component embedded in the stack. At least one electrically insulating layer structure includes a reinforced layer structure, which is arranged at an outer main surface of the stack. Further described is a method for manufacturing such a coreless component carrier and preferably simultaneously a further coreless component carrier of the same type.

A metal-clad laminate includes: an insulating layer; and a metal foil being in contact with at least one surface of the insulating layer. The insulating layer contains a cured product of a resin composition containing a polyphenylene ether copolymer having an intrinsic viscosity of 0.03 to 0.12 dl/g measured in methylene chloride at 25° C. and having an average of 1.5 to 3 specific groups per molecule at its molecular terminal, a thermosetting curing agent having two or more carbon-carbon unsaturated double bonds at its molecular terminal, and a thermoplastic elastomer. The metal foil includes a metal substrate, and a cobalt-containing barrier layer provided on at least a contact surface of the metal substrate, the contact surface being in contact with the insulating layer. The contact surface has a ten-point average roughness Rz of 2 μm or less as a surface roughness.

A metal-clad laminate includes: an insulating layer; and a metal layer stacked on the insulating layer. The insulating layer includes: a first layer; and a second layer interposed between the first layer and the metal layer. The first layer contains a cured product of a first resin composition containing composite particles. The second layer contains a cured product of a second resin composition. The first resin composition contains composite particles, each having a core containing a fluororesin and a shell containing a silicon oxide that coats the core at least partially. The second resin composition may or may not contain composite particles. When the second resin composition contains the composite particles, a ratio of the composite particles in the second resin composition to solid content of the second resin composition is lower than a ratio of the composite particles in the first resin composition to solid content of the first resin composition.