A circuit board according to the embodiment includes a first substrate including a first insulating layer and a first pad disposed on an upper surface of the first insulating layer; a second substrate including a second insulating layer including a via hole and a metal layer formed on upper and lower surfaces of the second insulating layer and an inner wall of the via hole; a third insulating layer disposed between the first substrate and the second substrate and having a first opening in a region overlapping the via hole; a via filling the via hole and disposed on the first pad exposed through the opening of the third insulating layer; and a second pad disposed on the via and the metal layer disposed on an upper surface of the second insulating layer.

A circuit board according to the embodiment includes a first substrate including a first insulating layer and a first pad disposed on an upper surface of the first insulating layer; a second substrate including a second insulating layer including a via hole and a metal layer formed on upper and lower surfaces of the second insulating layer and an inner wall of the via hole; a third insulating layer disposed between the first substrate and the second substrate and having a first opening in a region overlapping the via hole; a via filling the via hole and disposed on the first pad exposed through the opening of the third insulating layer; and a second pad disposed on the via and the metal layer disposed on an upper surface of the second insulating layer.

Provided is a photosensitive resin composition containing: a photopolymerizable compound (A) having an ethylenically unsaturated group; a photopolymerization initiator (B); and an inorganic filler (F), in which the photopolymerizable compound (A) having an ethylenically unsaturated group includes a photopolymerizable compound (A1) having an acidic substituent and an alicyclic structure together with an ethylenically unsaturated group, and the inorganic filler (F) includes an inorganic filler surface-treated with a coupling agent without at least one functional group selected from the group consisting of an amino group and a (meth)acryloyl group. The present disclosure also provides a photosensitive resin composition for photo via formation, and a photosensitive resin composition for interlayer insulating layer. The present disclosure further provides: a photosensitive resin film and a photosensitive resin film for interlayer insulating layer, each of which contains the photosensitive resin composition; a multilayered printed wiring board and a semiconductor package; and a method for producing a multilayered printed wiring board.

Provided is a photosensitive resin composition containing: a photopolymerizable compound (A) having an ethylenically unsaturated group; a photopolymerization initiator (B); and an inorganic filler (F), in which the photopolymerizable compound (A) having an ethylenically unsaturated group includes a photopolymerizable compound (A1) having an acidic substituent and an alicyclic structure together with an ethylenically unsaturated group, and the inorganic filler (F) includes an inorganic filler surface-treated with a coupling agent without at least one functional group selected from the group consisting of an amino group and a (meth)acryloyl group. The present disclosure also provides a photosensitive resin composition for photo via formation, and a photosensitive resin composition for interlayer insulating layer. The present disclosure further provides: a photosensitive resin film and a photosensitive resin film for interlayer insulating layer, each of which contains the photosensitive resin composition; a multilayered printed wiring board and a semiconductor package; and a method for producing a multilayered printed wiring board.

The circuit board according to the present invention includes a wiring portion and a non-wiring portion, the wiring portion having a metal layer and a resin layer, the non-wiring portion having a resin layer, the resin layer at a frequency 10 GHZ having a relative permittivity of from 2 to 3 at 23° C., and the circuit hoard satisfying a relationship: (A−B)/B≤0.1 wherein A is the maximum value of the thickness in the wiring portion (μm) and B is the minimum value of the thickness in the non-wiring portion (μm).

The circuit board according to the present invention includes a wiring portion and a non-wiring portion, the wiring portion having a metal layer and a resin layer, the non-wiring portion having a resin layer, the resin layer at a frequency 10 GHZ having a relative permittivity of from 2 to 3 at 23° C., and the circuit hoard satisfying a relationship: (A−B)/B≤0.1 wherein A is the maximum value of the thickness in the wiring portion (μm) and B is the minimum value of the thickness in the non-wiring portion (μm).

A circuit board with conductive wiring which is precisely shaped and sized includes a two-part conductive element, namely a first conductive wiring layer and a second conductive wiring layer, a first cover film and a second cover film. The first conductive wiring layer and the second conductive wiring layer are in direct contact to each other. A projection of the first conductive wiring layer and a projection of the second conductive wiring layer along a direction perpendicular to the circuit board overlap with each other. The first and the second cover films wrap the first and the second conductive wiring layers, respectively.

A method for manufacturing a flexible circuit board capable of transmitting high frequency signals with reduced attenuation includes providing an inner wiring board including a first conductive wiring layer and a first substrate layer, the first conductive wiring layer including a signal line and two ground lines on both sides of the signal line, the first substrate layer covering a side of the first conductive wiring layer and defining first through holes which expose the signal line; providing two copper clad laminates including a second substrate layer and a copper foil, the second substrate layer having second through hole aligned with the first through holes; laminating the two copper clad laminates onto two sides of the inner wiring board via two adhesive layers, each adhesive layer defining third through holes aligned with the first and second through holes; and forming a second conductive wiring layer from the copper foil.

A method for manufacturing a flexible circuit board capable of transmitting high frequency signals with reduced attenuation includes providing an inner wiring board including a first conductive wiring layer and a first substrate layer, the first conductive wiring layer including a signal line and two ground lines on both sides of the signal line, the first substrate layer covering a side of the first conductive wiring layer and defining first through holes which expose the signal line; providing two copper clad laminates including a second substrate layer and a copper foil, the second substrate layer having second through hole aligned with the first through holes; laminating the two copper clad laminates onto two sides of the inner wiring board via two adhesive layers, each adhesive layer defining third through holes aligned with the first and second through holes; and forming a second conductive wiring layer from the copper foil.

Disclosed herein a thin film capacitor that includes a lower electrode layer, an upper electrode layer, and a dielectric layer disposed between the lower electrode layer and the upper electrode layer. The lower electrode layer includes a first metal layer positioned on a side facing the dielectric layer and a second metal layer positioned on a side facing away from the dielectric layer. The first metal layer has a first surface positioned on a side facing the second metal layer and a second surface positioned on a side facing the dielectric layer. The first surface has a surface roughness higher than that of the second surface. The second metal layer reflects a surface property of the first surface.