A circuit board according to an embodiment includes an insulating layer including a first via hole; a first via disposed in the first via hole of the insulating layer; wherein the first via includes: a first via part disposed in a first region of the first via hole; and a second via part disposed in a second region other than the first region of the first via hole; wherein the second region is a central region of the first via hole, and the first region is an outer region surrounding the second region; wherein the first via part and the second via part includes: a first surface in contact with each other; and a second surface other than the first surface exposed on the insulating layer; wherein the first surface has a first surface roughness; wherein the second surface has a second surface roughness different from the first surface roughness.

A method may include obtaining a printed circuit board (PCB) that includes a set of vias that include a set of stub regions. The PCB may include a set of layers perpendicular to the set of vias. The set of layers may include a signal layer and a ground layer. The ground layer may be located between the set of stub regions and the signal layer. The method may include drilling to remove at least a portion of a stub region of a via of the set of vias. The method may include performing an electrical test to determine whether a sliver of conductive material is included within the via after drilling to remove the at least a portion of the stub region of the via.

A component carrier with a stack including an electrically insulating layer structure and an electrically insulating structure has a tapering blind hole formed in the stack and an electrically conductive plating layer extending along at least part of a horizontal surface of the stack outside of the blind hole and along at least part of a surface of the blind hole. A minimum thickness of the plating layer at a bottom of the blind hole is at least 8 μm. A demarcation surface of the plating layer in the blind hole and facing away from the stack extends laterally outwardly from the bottom of the blind hole towards a lateral indentation and extends laterally inwardly from the indentation up to an outer end of the blind hole. An electrically conductive structure fills at least part of a volume between the plating layer and an exterior of the blind hole.

According to an aspect of the present disclosures, a method of making a flexible printed circuit board, which includes a base film having an insulating property, a conductive pattern disposed on either one or both surfaces of the base film, and a cover layer covering a conductive-pattern side of a laminated structure inclusive of the base film and the conductive pattern, includes a superimposing step of superimposing a cover film on the conductive-pattern side of the laminated structure, the cover film having a first resin layer and a second resin layer that is laminated to an inner side of the first resin layer and that softens at a lower temperature than does the first resin layer, and a pressure bonding step of vacuum bagging the laminated structure and the cover film at a temperature higher than a softening temperature of the second resin layer.

A component carrier with an electrically insulating layer having a front side and a back side, a first and a second electrically conductive layer covering the front side and the back side of the electrically insulating layer, respectively. A through hole extends through both electrically conductive layers and the electrically insulating layer. An overhang is formed along one of the electrically conductive layers and sidewalls of the electrically insulating layer structure delimiting the through hole. An annular plating layer covers the sidewalls and fills part of the overhang such that a horizontal extension of the overhang after plating is less than 20 μm and/or such that a ratio between a horizontal extension of the overhang after plating and a width of a first window through the first electrically conductive layer and/or a width of a second window through the second electrically conductive layer is smaller than 20%.

An insulating sheet for use in forming an insulating layer of an interconnect substrate includes a semi-cured insulating resin layer, a semi-cured protective resin layer laminated on an upper surface of the insulating resin layer, and a cover layer laminated on an upper surface of the protective resin layer, wherein the protective resin layer has lower resistance to a predetermined solution than the insulating resin layer has, the predetermined solution being capable of dissolving the insulating resin layer and/or the protective resin layer.

A method for forming a circuit board having a dielectric core, a foil top surface, and a thin foil bottom surface with a removable foil backing of sufficient thickness to absorb heat from a laser drilling operation to prevent the penetration of the thin foil bottom surface during laser drilling utilizes a sequence of steps including a laser drilling step, removing the foil backing step, electroless plating step, patterned resist step, electroplating step, resist strip step, tin plate step, and copper etch step, which provide dot vias of fine linewidth and resolution.

A method for manufacturing a circuit board with nickel resistor embedded therein provides a copper substrate, the copper substrate includes a copper foil. A nickel resistance layer is formed on the copper foil. A first dielectric layer and a first copper layer are formed on the nickel resistance layer. The copper foil and the first copper layer are etched to form a first conductive wiring layer and a second conductive wiring layer respectively, the nickel layer not being subjected to an etching process, to obtain the finished circuit board.

Problem: To provide a method for manufacturing a laminate body with excellent heat resistance (solder heat resistance, for example), in which a small diameter via hole can be formed. RESOLUTION MEANS: The provision of a manufacturing method of a laminate body, containing: a step of forming onto a supporting body a curable resin composition layer formed from a thermosetting resin composition to obtain a curable resin composition layer with a supporting body; a step of laminating the aforementioned curable resin composition layer with a supporting body onto a substrate on a curable resin composition layer forming surface side to obtain a pre-curing composite with a supporting body formed from a substrate and a curable resin composition layer with a supporting body; a step of performing a first heating of the aforementioned composite and thermally curing the aforementioned curable resin composition layer to form a cured resin layer to obtain a cured composite with a supporting body formed from a substrate and a cured resin layer with a supporting body; a step of performing hole punching from the aforementioned supporting body side of the aforementioned cured composite with a supporting body to form a via hole in the aforementioned cured resin layer; a step of peeling the aforementioned supporting body from the aforementioned cured composite with a supporting body to obtain a cured composite formed from a substrate and a cured resin layer, a step of performing a second heating of the cured composite; a step of removing resin residue in the via hole of the aforementioned cured composite; and an step of forming a conductor layer on an inner wall surface of the via hole of the aforementioned cured composite and on the aforementioned cured resin layer; wherein the forming of the conductor layer in the via hole is performed via electroless plating or a combination of electroless plating and electrolytic plating.

A method for producing a wiring circuit board includes a first step of preparing a wiring circuit board assembly sheet including a support sheet, a plurality of wiring circuit boards supported by the support sheet, and a joint connecting the support sheet to the plurality of wiring circuit boards, having flat-shaped one surface and the other surface facing one surface at spaced intervals thereto in a thickness direction, and having a thin portion in which the other surface is recessed toward one surface and a second step of forming a burr portion protruding toward the other side in the thickness direction and cutting the thin portion.