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.

A connection body includes a circuit board terminals arranged into terminal rows, the terminals rows being arranged in parallel to one another in a widthwise direction orthogonal to a direction in which the terminals are arranged, and an electronic component including bumps arranged into bump rows corresponding to the terminal rows, the bumps being arranged in parallel to one another in a widthwise direction orthogonal to a direction in which the bumps are arranged. The electronic component is connected upon the circuit board interposed by an anisotropic conductive adhesive including electrically conductive particles arranged therein. A distance between mutually opposing terminals of the terminals and bumps of the bumps arranged toward the outer sides of the circuit board and the electronic component is greater than a distance between mutually opposing terminals of the terminals and bumps of the bumps arranged toward their inner sides.

A printed wiring board includes a laminated base material including an insulating layer and a conductor layer formed on the insulating layer, and a solder resist layer laminated on the laminated material and including photosensitive resin. The resist layer has surface portion and portion in contact with the laminated material, the conductor layer has pattern including conductor pads in contact with the resist layer such that the pads are positioned in openings in the resist layer, and the resist layer satisfies a first condition that a chemical species derived from a photopolymerization initiator has concentration higher in the portion in contact with the laminated material than concentration in the surface portion and/or a second condition that the chemical species derived from the initiator in the portion in contact with the laminated material has photopolymerization initiating ability higher than a chemical species derived from a photopolymerization initiator in the surface portion.

Provided is an electronic device capable of supplying large current to a circuit pattern, without employing a thick film structure for the circuit pattern. The electronic device includes a substrate, a wiring layer placed on the upper surface of the substrate, an electronic component mounted above the wiring layer, and a bonding layer placed between the electronic component and the wiring layer. The wiring layer and the bonding layer are porous layers containing pores. The bonding layer has higher volume density than the wiring layer except underneath the electronic component.

A first embodiment of a substrate for a high-frequency printed wiring board according to the present disclosure is directed to a substrate for a high-frequency printed wiring board, the substrate including: a dielectric layer including a fluororesin and an inorganic filler; and a copper foil layered on at least one surface of the dielectric layer, wherein a surface of the copper foil at the dielectric layer side has a maximum height roughness (Rz) of less than or equal to 2 ?m, and a ratio of the number of inorganic atoms of the inorganic filler to the number of fluorine atoms of the fluororesin in a superficial region of the dielectric layer at the copper foil side is less than or equal to 0.08.

A wiring substrate includes an insulating layer including a first layer and a second layer, and a conductor layer including a metal film formed on a surface of the second layer of the insulating layer such that the conductor layer includes a conductor pattern. The first layer includes resin and first inorganic particles, the second layer includes resin and second inorganic particles at the content rate that is lower than the content rate of the first inorganic particles in the first layer, and the thickness of the first layer is 90% or more of the thickness of the insulating layer. The second layer of the insulating layer includes a composite layer having the thickness in the range of 0.1 to 0.3 ?m, and the composite layer includes part of the metal film in the conductor layer formed in gaps between the second inorganic particles and resin in the second layer.

Ensure conduction between an electronic component and a circuit substrate having reduced pitches in wiring of the circuit substrate or electrodes of the electronic component and prevent short circuits between electrode terminals of the electronic component. A connection body has an electronic component connected to a circuit substrate via an anisotropic conductive adhesive agent; the anisotropic conductive adhesive agent contains a binder resin layer in which conductive particles are regularly arranged; an inter-particle distance among the conductive particles in a space between connection electrodes formed on the electronic component being greater than the inter-particle distance among the conductive particles trapped between the connection electrodes and substrate electrodes formed on the circuit substrate.

The prepreg includes a first resin layer and a second resin layer disposed on both surfaces of the first resin layer. The first resin layer is a half-cured product of a first resin composition that includes a glass cloth impregnated with the first resin composition and contains no hexagonal boron nitride. The second resin layer is a half-cured product of a second resin composition containing hexagonal boron nitride. The glass cloth has a warp and weft weave density of 54 pieces/25 mm or more. The hexagonal boron nitride has an average particle size ranging from 10 m to 30 m. The hexagonal boron nitride is contained in an amount ranging from 20 parts by mass to 40 parts by mass relative to 100 parts by mass of a residual component other than the hexagonal boron nitride in the second resin composition.

A multilayer ceramic substrate according to the present invention includes a plurality of base layers that are laminated containing a low-temperature co-fired ceramic material, a plurality of first constraint layers which contain a metal oxide not completely sintered at the sintering temperature of the low-temperature co-fired ceramic material and which are located between the base layers, and a protective layer which contains the metal oxide and which is in contact with an outermost base layer of the plurality of base layers in the lamination direction, and wherein X1>X2, where X1 is a content of the metal oxide in a surface section of the protective layer and X2 is a content of the metal oxide in a boundary section of the protective layer that is in contact with the outermost base layer.

A wiring board includes a laminate in which at least one first insulating layer containing first insulating particles and a first insulating resin, and at least one second insulating layer containing second insulating particles having a particle size smaller than a particle size of the first insulating particles and a second insulating resin are alternately positioned; a groove for wiring positioned at least on an upper surface of the laminate and including a side surface and a bottom surface; a via hole positioned in the first insulating layer of the laminate; and a wiring conductor positioned in the groove for wiring and in the via hole. The bottom surface of the groove for wiring is positioned in the second insulating layer.