A wiring board includes a photosensitive insulating layer and a first wiring layer. The photosensitive insulating layer has a hole, a first surface and a second surface opposite to each other. The hole has a first end opening formed in the first surface, a second end opening formed in the second surface, an axis, and a sidewall surrounding the axis. Part of the sidewall extends toward the axis to form at least one annular flange. The first wiring layer is disposed on the first surface and includes a first pad, in which the hole exposes the first pad. There is at least one recessed cavity between the annular flange and the first pad. The minimum width of the annular flange is smaller than the maximum width of the recessed cavity.

The resin composition of the present invention is a resin composition containing: a bismaleimide compound (A) containing a constituent unit represented by the following formula (1) and maleimide groups at both ends of the molecular chain; a compound (B) containing one or more carboxy groups; and a photo initiator (C). ##STR00001##
In the formula (1), R.sub.1 represents a linear or branched alkylene group having 1 to 16 carbon atoms, or a linear or branched alkenylene group having 2 to 16 carbon atoms. R.sub.2 represents a linear or branched alkylene group having 1 to 16 carbon atoms, or a linear or branched alkenylene group having 2 to 16 carbon atoms. Each R.sub.3 independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 16 carbon atoms, or a linear or branched alkenyl group having 2 to 16 carbon atoms. Each n independently represents an integer of 1 to 10.

A printed circuit board according to an embodiment includes a first insulating layer; a second insulating layer disposed on the first insulating layer; and a cavity formed in the first and second insulating layers; wherein the cavity includes a first portion formed in the second insulating layer; and a second portion formed in the first insulating layer; wherein the first portion has a first cross-sectional shape, and wherein the second part has a second cross-sectional shape different from the first cross-sectional shape.

To provide a negative photosensitive resin composition which exhibits satisfactory resolution even when shifts occur in focus depth, and which has satisfactory adhesion to a mold resin and exhibits a low dielectric constant; a method for producing a polyimide using the photosensitive resin composition; a method for producing a cured relief pattern; and a semiconductor device including the cured relief pattern.

Disclosed is a negative photosensitive resin composition including a polyimide precursor having a structure represented by general formula (A1), (B) a photopolymerization initiator, and (C) a solvent.

##STR00001##

By interposing a hard mask between a dielectric and photo-sensitive material it is possible to form fine via in the dielectric by dry etching without damaging the remaining surface of the dielectric.

A method for preparing a PCB product having highly dense conductors, the method including providing a PCB substrate including a conductive layer, employing an inkjet printer to selectively print unexposed photosensitive patterns on the PCB substrate, the unexposed photosensitive patterns having a thickness of less than 5 pm, exposing the photosensitive patterns to radiation thereby to define exposed patterns, the exposed patterns having a pitch less than 20 pm and wet etching the conductive layer in accordance with a pattern defined by the exposed patterns thereby to define the highly dense conductors having a pitch of less than 30 pm.

A circuit board includes a substrate, a first circuit layer, a second circuit layer, and a third circuit layer. The substrate includes a base layer, a first metal layer formed on the base layer, and a seed layer formed on the first metal layer. The first circuit layer is located on the substrate and includes the first metal layer and a signal layer formed on a surface of the first metal layer. The second circuit layer is coupled to the first circuit layer and includes the first metal layer, the seed layer, and a connection pillar formed on a surface of the first metal layer and the seed layer. The third circuit layer is coupled to the second circuit layer and includes the seed layer and a coil formed on a surface of the seed layer.

The present disclosure provides a photosensitive dry film enabling a photocured film being excellent in insulation reliability and resolution and having a frosted appearance to be obtained. A photosensitive dry film including a support film having a first main surface and a second main surface opposite to the first main surface, and a photosensitive resin layer provided on the first main surface, in which the first main surface has an irregular surface formed by chemical etching.

An aliphatic polycarbonate resin for forming a partition containing a constituent unit represented by the formula (1): ##STR00001##
wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are each independently a hydrogen atom, an alkyl group having one or more carbon atoms, an alkoxyalkyl group having two or more carbon atoms, an aryl group, or an aryloxyalkyl group; at least one of R.sup.1, R.sup.2, R.sup.3, and R.sup.4 is an alkyl group having two or more carbon atoms, an alkoxyalkyl group having two or more carbon atoms, an aryl group, or an aryloxyalkyl group; and R.sup.1, R.sup.2, R.sup.3, and R.sup.4 may be the same or different; and the aliphatic polycarbonate resin has a contact angle against water of 75° or more. Also disclosed is a partition material including the aliphatic polycarbonate resin, a substrate, a method of producing the substrate, a method for producing a wiring substrate, and a wiring forming method.

A method for producing a wired circuit board, the method including the steps of: a first step of providing an insulating layer having an opening penetrating in the thickness direction at one side surface in the thickness direction of the metal plate, a second step of providing a first barrier layer at one side surface in the thickness direction of the metal plate exposed from the opening by plating, a third step of providing a second barrier layer continuously at one side in the thickness direction of the first barrier layer and an inner surface of the insulating layer facing the opening, a fourth step of providing a conductor layer so as to contact the second barrier layer, and a fifth step of removing the metal plate by etching.