Provided are a film including a matrix material, and a particle having an elastic modulus at 25° C. which is higher than an elastic modulus of the matrix material, in which the film has a region A at at least a part between the matrix material and the particle, and the region A contains a compound having a loss tangent of 0.1 or greater at 25° C.; and a laminate formed of the film.

A flexible wiring board that includes a flexible substrate; a flexible wiring over the flexible substrate; and a protective layer over the flexible substrate, where the protective layer includes: a first region that overlaps with the flexible wiring and a second region that does not overlap with the flexible wiring as viewed from a thickness direction of the flexible substrate, and a low flexibility part that is higher in flexibility ratio than the first region and is disposed along an extending direction of the flexible wiring in the second region.

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.

Provided is a resin composition having excellent dielectric characteristics, i.e., low dielectric characteristics, in the high-frequency region, and excellent dielectric characteristics, i.e., low dielectric characteristics, under high humidity, and having practical adhesion to metal and resin substrates. More specifically, provided is a resin composition comprising an acid-modified polyolefin, an epoxy resin, and an inorganic filler, wherein a cured product of the resin composition has a dielectric loss tangent of 0.003 or less at a frequency of 10 GHz at 25° C. after storage for 168 hours under conditions of 85° C. and 85% RH (relative humidity).

A circuit board according to an embodiments includes an insulating portion comprising a plurality of insulating layers, wherein the insulating portion includes: a first insulating portion; a second insulating portion disposed on the first insulating portion and having a coefficient of thermal expansion corresponding to the first insulating portion; and a third insulating portion disposed under the first insulating portion and having a coefficient of thermal expansion corresponding to the first insulating portion; wherein the first insulating portion includes a prepreg including glass fibers, and wherein the second and third insulating portions include a resin coated copper (RCC) with a coefficient of thermal expansion in the range of 10 to 65 (10.sup.−6 m/m.Math.k).

A curable composition is provided that includes an alkenyl phenol A, an epoxy-modified silicone B, an epoxy compound C other than the epoxy-modified silicone B, and a thermosetting resin E, in which the thermosetting resin E contains one or more selected from the group consisting of a maleimide compound, a cyanate ester compound, a phenolic compound, an alkenyl-substituted nadimide compound, and an epoxy compound.

An organic board of the present disclosure has a resin component comprising at least one resin selected from the group consisting of an epoxy resin, a polyimide resin, a phenolic resin, an amino resin, a polyester resin, a polyphenylene resin, a cyclic olefin resin, and a Teflon (registered trademark) resin as the main component, and a non-resin component including at least one of an inorganic filler and a flame retardant, in which the non-resin component is dispersed in the resin component, at least a part of the non-resin component is agglomerated to form an aggregate, a part of the resin component forms a resin material part having a particle shape, the resin material part exists within the aggregate, or the resin component forms a matrix phase surrounding the aggregate, and there are voids at some interfaces between the resin component and the aggregate.

A method of manufacturing a package unit, comprising: preparing a circuit board having a first region, a second region surrounding the first region, and a third region between the first and the second region; preparing a mold having a frame-shaped protruding portion surrounding a first cavity, the frame-shaped protruding portion partitioning the first cavity and a second cavity surrounding the first cavity; arranging the circuit board and the mold such that the first region of the circuit board faces the first cavity, the second region of the circuit board faces the second cavity, and a gap which communicates the first cavity and the second cavity with each other is formed between the frame-shaped protruding portion and the third region of the circuit board; and forming a frame-shaped resin member on top of the second region of the circuit board by pouring a resin into the second cavity.

The present disclosure relates to a dielectric substrate that may include a polyimide layer and a first filled polymer layer overlying the polyimide layer. The first filled polymer layer may include a resin matrix component, and a first ceramic filler component. The first ceramic filler component may include a first filler material. The first filler material may further have a mean particle size of at not greater than about 10 microns.