A method of making a printed circuit board includes a step of providing a double-sided plate that is an insulating substrate having conductive layers on respective surfaces thereof, a first coating step of coating a first surface of the double-sided plate with a first photosensitive resin film, a second coating step of coating a second surface of the double-sided plate with a second photosensitive resin film, a first exposure step of exposing the photosensitive resin film coating the first surface after the first and second coating steps, and a second exposure step of exposing the photosensitive resin film coating the second surface after the first exposure step, wherein a maximum depth of a depression in an outermost surface of the second photosensitive resin film used in the second exposure step is less than 1.0 μm.

A semi-flex component carrier includes a stack having at least one electrically insulating layer structure, at least one electrically conductive layer structure and a stress propagation inhibiting barrier. The stack defines at least one rigid portion and at least one semi-flexible portion. The stress propagation inhibiting barrier includes a plurality of stacked vias filled at least partially with electrically conductive material in an interface region between the at least one rigid portion and the at least one semi-flexible portion and configured to inhibit stress propagation between the at least one rigid portion and the at least one semi-flexible portion during bending.

A composite film for electronic device using high frequency band signals, which is low in dielectric tangent, excellent in embedding properties relative to unevenness of a circuit, etc., and excellent in surface smoothness, and has high adhesion to plated copper is provided; and a printed wiring board containing a cured material of the composite film for electronic device and a method of producing the printed wiring board are also provided. Specifically, the composite film for electronic device is a composite film for electronic device using high frequency band signals, including a layer A having a minimum melt viscosity at 80 to 150° C. of 100 to 4,000 Pa.Math.s; and a layer B having a minimum melt viscosity at 80 to 150° C. of 50,000 Pa.Math.s or more. The composite film for electronic device is low in thermal expansion properties and excellent in handling properties of film.

A resin sheet according to the present disclosure includes an uncured product or semi-cured product of a thermosetting resin composition. A melt viscosity of the resin sheet is equal to or greater than 10 Pa.Math.s and equal to or less than 2000 Pa.Math.s when measured using a Koka flow tester under a measuring condition including 130° C. and 1 MPa and is equal to or greater than 6 Pa.Math.s and equal to or less than 1200 Pa.Math.s when measured using the Koka flow tester under a measuring condition including 130° C. and 4 MPa.

One aspect of the present invention relates to a resin composition containing a polyrotaxane (A), an epoxy resin (B), and a curing agent (C), in which the curing agent (C) contains an acid anhydride (C-1) in an amount of 0.1 parts by mass or more and less than 10 parts by mass based on a total of 100 parts by mass of the polyrotaxane (A), the epoxy resin (B), and the curing agent (C).

A method for manufacturing a package substrate including an insulating layer and a wiring conductor, including: forming, on one or both sides of a core resin layer, a substrate including a peelable first metal layer that has a thickness of 1-70 μm, a first insulating resin layer, and a second metal layer; forming a non-through hole reaching a surface of the first metal layer, performing electrolytic and/or electroless copper plating on its inner wall, and connecting the second and first metal layers; arranging a second insulating resin layer and a third metal layer and heating and pressurizing the first substrate to form a substrate; forming a non-through hole reaching a surface of the second metal layer, performing electrolytic and/or electroless copper plating on its inner wall, and connecting the second and third metal layers; peeling a third substrate; and patterning the first and third metal layers to form the wiring conductor.

A method of making a printed circuit board structure including a closed cavity is provided. The method can include the steps of forming a cavity in a core structure of a core layer, laminating each of a top surface and a bottom surface of the core structure with an adhesive layer and a metal layer to prepare a laminate structure and cover the cavity to define a closed cavity. The method also includes forming vias through the laminate structure, and patterning the metal layers in the laminate structure.

A member for forming a wiring includes an adhesive layer and a metal foil layer. The adhesive layer is formed from an adhesive composition including electrically conductive particles. The metal foil layer is disposed on the adhesive layer. In this member for forming a wiring, a ratio of surface roughness Rz of a first surface of the metal foil layer on a side attached to the adhesive layer with respect to an average particle diameter of the electrically conductive particles is 0.05 to 3.

Provided are a phenoxy resin having excellent heat resistance, low hygroscopicity, and solvent solubility, a resin composition using the same, and a cured object obtained therefrom. The phenoxy resin is represented by Formula (1) below and has an Mw of 10,000 to 200,000: ##STR00001##
where, X represents a divalent group, and includes, essentially, a group having a cyclohexane ring structure and a group having a fluorene ring structure. Y represents a hydrogen atom or a glycidyl group. n is the number of repetitions and an average value thereof is 25 to 500.

A reel-to-reel lamination method to laminate a metal foil or circuitry pattern on the fly. The method includes applying a UV laminate or thermoset laminate to the metal foil or the circuitry pattern reel to reel, and then apply a UV radiation or heat to the laminate. There can be an optional enclosure connected to a suction source. The enclosure can have a flexible bladder that physically compresses the laminate.