There is provided a manufacturing method for an insulating resin circuit substrate, which is a manufacturing method for an insulating resin circuit substrate which includes an insulating resin layer composed of a polyimide resin and a circuit layer consisting of metal pieces disposed in a circuit pattern shape on one surface of the insulating resin layer. The manufacturing method includes a temporary fixing step of pressurizing the metal pieces toward the resin sheet material while heating the metal pieces to temporarily fix the metal pieces and a joining step of disposing a cushion material on a side of the metal pieces which are temporarily fixed and pressurizing the metal pieces and the resin sheet material in a laminating direction, while heating the metal pieces and the resin sheet material, to join the resin sheet material and the metal pieces.

A circuit board includes an inner circuit substrate and an outer circuit substrate electrically connected to the inner circuit substrate. The outer circuit substrate includes an outer dielectric layer and an outer circuit layer facing the inner circuit substrate embedded in the outer dielectric layer. A portion of the outer circuit layer facing away from the inner circuit substrate protruding from the outer dielectric layer. The circuit board can increase contact area between the outer circuit layer and the outer dielectric layer, improving adhesion between the outer circuit layer and the outer dielectric layer, and reducing a thickness of the outer circuit substrate, thereby reducing the overall thickness of the circuit board.

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.

Provided is a surface-treated copper foil excellent in laser processability. The surface-treated copper foil includes a roughened surface formed by subjecting a surface to a roughening treatment, in which when measured using a three-dimensional roughness meter, the roughened surface has a surface skewness Ssk within a range of from −0.300 to less than 0 and an arithmetic mean summit curvature Ssc within a range of from 0.0220 nm.sup.−1 to less than 0.0300 nm.sup.−1.

In a method for producing a wired circuit board includes a step (1), in which the insulating layer having an inclination face is provided; a step (2), in which a metal thin film is provided on the surface of the insulating layer including the inclination face; a step (3), in which a photoresist is provided on the surface of the metal thin film; a step (4), in which a photomask is disposed so that a first light exposure portion and a second light exposure portion in the photoresist are exposed to light, and the photoresist is exposed to light; a step (5), in which the first light exposure portion and the second light exposure portion are removed; and a step (6), in which the first wire and the second wire are provided on the surface of the metal thin film.

An insulated metal substrate (IMS) and a method for manufacturing the same are disclosed. The IMS includes an electrically conductive line pattern layer, an encapsulation layer, a first adhesive layer, a second adhesive layer, and a heat sink element. The encapsulation layer fills a gap between a plurality of electrically conductive lines of the electrically conductive line pattern layer. An upper surface of the encapsulation layer is flush with an upper surface of the electrically conductive line pattern layer. The first and second adhesive layer are disposed between the electrically conductive line pattern layer and the heat sink element. A bonding strength between the first adhesive layer and the second adhesive layer is greater than 80 kg/cm.sup.2.

Provided are a thermoplastic polymer capable of reducing a dielectric dissipation factor in high frequency bands and a film thereof. The thermoplastic liquid crystal polymer includes repeating units represented by the following formulae (I), (II), (III) and (IV), in which a molar ratio of a total amount of the repeating units represented by formulae (I) and (II) to a total amount of all the repeating units in the thermoplastic liquid crystal polymer is 50 to 90 mol %, and a molar ratio of the repeating unit represented by formula (III) to the repeating unit represented by formula (IV) is the former/the latter=23/77 to 77/23.

A resin composition capable of achieving a printed wiring board or the like excellent in heat dissipation properties, water absorption properties, copper foil peel strength, and heat resistance after moisture absorption is provided. A prepreg, a laminate, a metal foil clad laminate, a printed wiring board and the like, which use the resin composition are also provided. The resin composition of the present invention having at least an epoxy resin, a cyanate ester compound, and an inorganic filler, wherein the inorganic filler includes at least a surface-treated silicon carbide of a silicon carbide powder having at least a part of the surface treated with an inorganic oxide.

A component (A1) thereof includes an epoxy resin having at least one of a naphthalene skeleton or a biphenyl skeleton. A component (A2) thereof includes a phenolic resin having at least one of the naphthalene skeleton or the biphenyl skeleton. A component (B) thereof includes a high molecular weight substance having structures expressed by at least formulae (b2) and (b3) out of formulae (b1), (b2), and (b3) and having a weight average molecular weight equal to or greater than 200,000 and equal to or less than 850,000. A component (C1) thereof includes a first filler obtained by subjecting a first inorganic filler to surface treatment using a first silane coupling agent expressed by formula (c1). A component (C2) thereof includes a second filler obtained by subjecting a second inorganic filler to surface treatment using a second silane coupling agent expressed by formula (c2).

A power electronic substrate includes a metallic baseplate having a first and second surface opposing each other. An electrically insulative layer also has first and second surfaces opposing each other, its first surface coupled to the second surface of the metallic baseplate. A plurality of metallic traces each include first and second surfaces opposing each other, their first surfaces coupled to the second surface of the electrically insulative layer. At least one of the metallic traces has a thickness measured along a direction perpendicular to the second surface of the metallic baseplate that is greater than a thickness of another one of the metallic traces also measured along a direction perpendicular to the second surface of the metallic baseplate. In implementations the electrically insulative layer is an epoxy or a ceramic material. In implementations the metallic traces are copper and are plated with a nickel layer at their second surfaces.