[Problem] To achieve a wiring board capable of suppressing the difference in the amount of delay between two signal wirings constituting differential signal wirings, while securing flexibility in design.

[Solution] A wiring board is configured to include a first insulating layer 1, a first signal wiring 2 and a second signal wiring 3. The first insulating layer 1 includes fibers 4 having the long axis in a first direction and aligned approximately parallel to each other at a first interval and an insulating material 5 filling gaps between the fibers 4 of the first direction. The first signal wiring 2 is formed approximately parallel to the first direction on the first insulating layer 1. The second signal wiring 3 is formed parallel to the first signal wiring 2 such that the interval between the first and second signal wirings 2 and 3 be approximately an integral multiple of the first interval, and the second signal wiring 3 transmits a differential signal of a signal transmitted on the first signal wiring 2.

A board main body includes first and second resin layers contacting each other and including thermoplastic resin, a first signal conductor layer on an upper main surface of the second resin layer, an overlapping region in which the first and second resin layers are present when viewed in an up-down direction, and a non-overlapping region in which the first resin layer is not present and the second resin layer is present when viewed in the up-down direction. The first signal conductor layer includes a first curved portion in which the first signal conductor layer is curved in the up-down direction such that the first signal conductor layer in the first non-overlapping region is above the first signal conductor layer in the overlapping region. The first signal conductor layer is electrically connectable to an element on the board main body in the first non-overlapping region.

Provided is a novel resin composition for a metal-clad laminate, with which a metal-clad laminate having excellent adhesion with a metal foil, solder heat resistance, insulation and the like can be produced. A terminally modified polybutadiene contained in the resin composition for a metal-clad laminate according to the present invention has a structure of formula (III) on each of both terminals of a polybutadiene comprising a repeating unit of formula (I) and a repeating unit of formula (II), wherein a proportion of the repeating unit of formula (I) in all the repeating units is 70 to 99% by mol.

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A resin sheet is provided having low dielectric properties, and a circuit board material using such a sheet. The resin sheet includes a resin layer containing a cyclic polyolefin resin copolymer having a crystal melting peak temperature of less than 100° C., the resin sheet having a dielectric loss tangent at 12 GHz of less than 0.005.

Printed wiring board manufacturing method, and printed wiring board. The method includes preparing sheet material including cloth-like material woven of reinforced fiber with a 90 degree between warp thread and a weft thread; arranging the sheet material on a cutting-out apparatus so that the sheet material is tilted 5 to 30 degrees with respect to threads configuring the cloth-like material and cutting a portion to cross the cloth-like-material configuration threads aligned on a cutting blade at 5 to 30 degrees; cutting the sheet material from the tilted sheet material with the cut portion crossing the cloth-like-material configuration threads aligned on the cutting blade to form the sheet material with a circumferential edge of the sheet material crossing the cloth-like material configuration threads at 5 to 30 degrees; creating a mother laminate configured with the sheet material as an inner-layer board or an insulating board; and providing a conductor pattern on a metal layer of the mother laminate along a circumferential edge portion of the mother laminate.

A substrate for a printed wiring board includes a base layer, and a copper foil directly or indirectly stacked on at least a part of one or both surfaces of the base layer. The base layer includes a matrix containing a fluororesin as a main component and one or more reinforcing material layers included in the matrix, and a ratio B/A is 0.003 to 0.37, where A is an average thickness of the base layer, and B is an average distance between a surface of the copper foil facing the matrix and a surface of a reinforcing material layer closest to the surface of the copper foil facing the copper foil.

This invention provides a material having a low dissipation factor that is suitable for use as an insulating material for a printed wiring board and the like; a resin composition used for the production of the material; and an application using the material. The present invention relates to a resin composition comprising a mono(C.sub.6-C.sub.20 alkyl)diallyl isocyanurate and a polyphenylene ether resin; a cured product of the resin composition; and use of the cured product.

A circuit board according to an embodiment includes an insulating layer including an upper surface and a lower surface, and having a via hole passing through the upper surface and the lower surface in a thickness direction from the upper surface to the lower surface, wherein the via hole includes: a first via part adjacent to the upper surface and having a constant inclination angle along the thickness direction; a second via part adjacent to the lower surface and having a constant inclination angle along the vertical direction; and a third via part disposed between the first via part and the second via part and having an inclination angle different from an inclination angle of the first via part and an inclination angle of the second via part.

A resin composition for wiring board material contains a thermosetting resin and a thermally expandable microcapsule, in which the relative dielectric constant (10 GHz) of a cured product of the resin composition is more than 1.0 and 2.2 or less.

The present invention relates to a resin composition including an acrylic polymer (A) and a thermosetting resin (B), wherein a phase separation structure of a first phase containing the acrylic polymer (A) and a second phase containing the thermosetting resin (B) is formed, and an average domain size of the second phase is 20 μm or less.