A printed circuit board includes: a plurality of insulating layers; a plurality of wiring pattern layers disposed on at least one surface of the plurality of insulating layers; a via connecting wiring pattern layers, among the plurality of wiring pattern layers, disposed on upper and lower surfaces of one of the plurality of insulating layers to each other; a connection pad disposed on a surface of an outermost layer among the plurality of insulating layers; and a solder resist having a hole exposing at least a portion of the connection pad. An external surface of the solder resist has surface roughness.

A printed circuit board includes a substrate and a plurality of pad forming regions disposed thereon. The plurality of pad forming regions are spaced apart from each other by a predetermined distance. A plurality of connection pads are disposed on a portion of the plurality of pad forming regions. The plurality of connection pads are configured to transmit or receive a signal to an external device or from the external device. The printed circuit board includes a path configured for the transportation of moisture therein.

A low dielectric constant (Dk) and dissipation factor (Df) of solder resistant mask composition having excellent photo and thermocurability, and high developability resolution with an alkaline aqueous solution, wherein the dielectric constant is below 3.20 (1 GHz), and the dissipation factor is less than 0.015 (1 GHz); and wherein the composition comprises (A) a photopolymerizable prepolymer; (B) a photopolymerizable vinyl monomer; (C) an epoxy compound; (D) a photopolymerization initiator; (E) an inorganic filler; (F) a catalyst; and (G) an organic solvent.

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.

An electronic device according to an embodiment may include: a Printed Circuit Board (PCB) including a first face and a second face; a semiconductor chip mounted on the second face; a conductive pad disposed on the second face; a solder resist layer disposed on the second face and including an aperture; an arc-shaped opening having an inner diameter and an outer diameter, disposed along an outer periphery of the conductive pad and in the aperture; and at least one external terminal disposed on the semiconductor chip and bonded to the conductive pad. The conductive pad may include: a first region having a smaller diameter than the outer diameter; and at least one second region extending from the first region in a first outer circumferential direction, and located at least in part between both ends of the opening. In addition, various embodiments recognized through the specification may also be possible.

An array of ultraviolet light emitting diodes can cure ultraviolet curable material, such as solder mask or ink, that has been applied to a substrate in connection with fabricating electronic circuit devices. The substrate can be placed in a housing associated with a processing station of a manufacturing operation. A mask or stencil can be positioned adjacent the substrate. The ultraviolet curable material can be applied to the substrate via the mask or stencil, for example using a squeegee. The ultraviolet light emitting diodes can be moved over the substrate to cure the ultraviolet curable material. The substrate with the cured material can be removed from the housing.

A radiation curable composition comprising at least one polymerizable compound and an adhesion promoter, characterized in that the adhesion promoter includes: —a polymerizable group selected from the group consisting of an acrylate, a methacrylate, an acrylamide, a methacrylamide, a styrene, a maleimide, a vinyl ether and a vinyl ester; and—an adhesion promoting group containing at least one nitrogen containing five or six membered heteroaromatic ring.

A circuit board according to an embodiment comprises: an insulating layer including first to third regions; an outer layer circuit pattern disposed on the upper surface of the first to third regions of the insulating layer; and a solder resist including a first part disposed in the first region of the insulating layer, a second part disposed in the second region, and a third part disposed in the third region, wherein the outer layer circuit pattern has a first height, the third part of the solder resist is disposed on the upper surface of the outer layer circuit pattern to have a second height, the first region includes a first sub-region and a second sub-region, the first part includes a first sub-part disposed in the first sub-region and a second sub-part disposed in the second sub-region, the upper surface of the first sub-part is located to be higher than the upper surface of the outer layer circuit pattern and lower than the upper surface of the third part, the upper surface of the second sub-part is located to be lower than the upper surface of the outer layer circuit pattern, and the surface roughness of the third part of the solder resist is different from the surface roughness of the first part of the solder resist.

A composite circuit board includes a composite circuit board unit, a first solder mask formed on a first metal protection layer of the composite circuit board unit, and a second solder mask formed on a second metal protection layer of the composite circuit board unit. Two ends of a first outer conductive circuit are bent back toward each other and spaced apart a predetermined distance to form a first window. Two ends of a second outer conductive circuit are bent back toward each other and spaced apart a predetermined distance to form a second window.

The display device includes: a display panel; a first circuit board having a first portion connected to one portion of the display panel and comprising a connector; and a second circuit board electrically connected to the first circuit board through the connector, wherein the first portion includes a base film, a dummy pad disposed on the base film, and a first solder mask partially covering the dummy pad and exposing a portion of the dummy pad, the dummy pad includes a covered region covered by the first solder mask and an exposed region exposed by the first solder mask, and a solder ball, The exposed region of the dummy pad is connected to the connector through a solder ball.