The present disclosure relates to a dielectric substrate that may include a polymer based core film, and a fluoropolymer based adhesive layer. The polymer based core film may include a resin matrix component, and a ceramic filler component. The ceramic filler component may include a first filler material. The particle size distribution of the first filler material may have a D.sub.10 of at least about 1.0 microns and not greater than about 1.7, a D.sub.50 of at least about 1.0 microns and not greater than about 3.5 microns, and a D.sub.90 of at least about 2.7 microns and not greater than about 6 microns.

The present disclosure relates to a multilayer circuit board manufacturing apparatus. The present disclosure includes: uncoiler configured to provide a member; a process unit configured to perform a process on the member provided from the uncoiler; a recoiler configured to wind the member on which the process is completed in the process unit; and a tension adjustment unit which is located in at least one of the uncoiler, the recoiler, a region between the uncoiler and the process unit, and a region between the process unit and the recoiler, and adjusts tension of the member.

A sheet material includes a resin layer containing a binder and polypyrrole particles, an electroless plating film provided on the side of one main surface of the resin layer and including first electroless plating films and a second electroless plating film, and a transparent base material provided on the side of the other main surface of the resin layer.

A method for manufacturing a wiring substrate includes forming a second resin insulating layer on a first resin insulating layer such that the second resin insulating layer is in contact with a surface of the first resin insulating layer, irradiating laser upon the second resin insulating layer such that a recess penetrating through the second resin insulating layer and exposing the first resin insulating layer is formed, and forming a conductor layer including conductor material filled in the recess formed through the second resin insulating layer such that the conductor layer is embedded in the second resin insulating layer. The second resin insulating layer are formed on the surface of the first resin insulating layer such that the first resin insulating layer and the second resin insulating layer have different processability with respect to the laser.

A magneto-dielectric material operable between a minimum frequency and a maximum frequency, having: a plurality of layers that alternate between a dielectric material and a ferromagnetic material, lowermost and uppermost layers of the plurality of layers each being a dielectric material; each layer of the plurality of ferromagnetic material layers having a thickness equal to or greater than 1/15.sup.th a skin depth of the respective ferromagnetic material at the maximum frequency, and equal to or less than ⅕.sup.th the skin depth of the respective ferromagnetic material at the maximum frequency; each layer of the plurality of dielectric material layers having a thickness and a dielectric constant that provides a dielectric withstand voltage across the respective thickness of equal to or greater than 150 Volts peak and equal to or less than 1,500 Volts peak; and, the plurality of layers having an overall thickness equal to or less than one wavelength of the minimum frequency in the plurality of layers.

Provided is a composite material that shows a low specific dielectric constant, and that hardly causes an appearance failure or changes in characteristics when exposed to, for example, a treatment liquid to be used in the production of an electronic circuit board. Specifically, a plate-like composite material including polytetrafluoroethylene and a predetermined filler, and satisfying a predetermined condition serves as a composite material that shows a low specific dielectric constant, and that hardly causes an appearance failure or changes in characteristics even when exposed to, for example, a treatment liquid to be used in the production of an electronic circuit board.

In an embodiment the dielectric layer comprises a fluoropolymer, a plurality of boron nitride particles, a plurality of titanium dioxide particles, a plurality of silica particles; and a reinforcing layer. The dielectric layer can comprise at least one of 20 to 45 volume percent of the fluoropolymer, 15 to 35 volume percent of the plurality of boron nitride particles, 1 to 32 volume percent of the plurality of titanium dioxide particles, 10 to 35 volume percent of the plurality of silica particles, and 5 to 15 volume percent of the reinforcing layer; wherein the volume percent values are based on a total volume of the dielectric layer.

A preparation method for a spherical silica powder filler, comprises the following steps: S1, providing spherical polysiloxane comprising T units by means of a hydrolysis condensation reaction of R.sub.1SiX.sub.3, wherein R.sub.1 is hydrogen atom or an independently selectable organic group having 1 to 18 carbon atoms, X is a hydrolyzable group, and the T unit is R.sub.1SiO.sub.3—; and S2, calcining the spherical polysiloxane under the condition of a dry oxidizing gas atmosphere at a calcining temperature between 850° C. and 1200° C., so as to obtain a spherical silica powder filler having a low hydroxyl content. The spherical silica powder filler is composed of at least one selected from Q.sub.1 unit, Q.sub.2 unit, Q.sub.3 unit and Q.sub.4 unit, wherein Q.sub.1 unit is Si(OH).sub.3O—, Q.sub.2 unit is Si(OH).sub.2O.sub.2—,Q.sub.3 unit is SiOHO.sub.3—, Q.sub.4 unit is SiO.sub.4—, and the content of Q.sub.4 unit is greater than or equal to 95%.

In an embodiment, a printed circuit board substrate (12) comprises a polymer matrix; a reinforcing layer (42); and a plurality of coated boron nitride particles (44); wherein the plurality of coated boron nitride particles comprise a coating having an average coating thickness of 1 to 100 nanometers. The polymer matrix can comprise at least one of an epoxy, a polyphenylene ether, polystyrene, an ethylene-propylene dicyclopentadiene copolymer, a polybutadiene, a polyisoprene, a fluoropolymer, or a crosslinked matrix comprising at least one of triallyl cyanurate, triallyl isocyanurate, 1,2,4-trivinyl cyclohexane, trimethylolpropane triacrylate, or trimethylolpropane trimethacrylate.

The wiring board according to the present disclosure includes: a first insulating layer including insulating particles; a plurality of first conductors located on the first insulating layer at an interval of a first distance from each other; a second conductor located on the first insulating layer at an interval of a second distance from the first conductor; and a second insulating layer located on the first insulating layer to cover the first conductor and the second conductors and including the insulating particles. When a boundary portion between the first insulating layer and the second insulating layer is viewed in cross-section in the thickness direction, the ratio of a first area occupied by the insulating particles in a first boundary portion including the first distance is higher than the ratio of a second area occupied by the insulating particles in a second boundary portion including the second distance.