A flexible circuit structure includes: a flexible substrate having a surface; a plurality of first pads disposed on the surface; and an insulating layer disposed on the surface and between two adjacent first pads of the plurality of first pads, wherein the insulating layer has a first maximum height in a normal direction of the surface, one of the plurality of first pads has a second maximum height in the normal direction of the surface, and the first maximum height is less than or equal to the second maximum height.

An extremely thin copper foil is provided that enables formation of highly fine different wiring patterns with a line/space (L/S) of 10 μm or less/10 μm or less on two sides of the copper foil and is thus usable as an inexpensive and readily processable substitution for silicon and glass interposers. The extremely thin copper foil includes, in sequence, a first extremely thin copper layer, an etching stopper layer, and the second extremely thin copper layer. Two sides of the extremely thin copper foil each have an arithmetic average roughness Ra of 20 nm or less.

Disclosed in a reel-to-reel surface press apparatus. The reel-to-reel surface press apparatus includes an uncoiler and a recoiler, both transferring a component in a reel-to-reel method, a press disposed between the uncoiler and the recoiler, comprising a press plate pressing the component, and having a plurality of reference holes at an equal pitch along an edge of the press plate, a feeder disposed at the rear of the uncoiler and moving the component, and a controller configured to control the component to be transferred based on at least any one of the plurality of reference holes.

According to one embodiment, a metal base circuit board includes a metal base substrate, a first circuit pattern, and a first insulating layer between the metal base substrate and the first circuit pattern. The first insulating layer covers a lower surface of the first circuit pattern and at least part of a side surface of the first circuit pattern, the lower surface facing the metal base substrate, the at least part of the side surface being adjacent to the lower surface.

According to one embodiment, a metal base circuit board includes a metal base substrate, a first circuit pattern, and a first insulating layer between the metal base substrate and the first circuit pattern. The first insulating layer covers a lower surface of the first circuit pattern and at least part of a side surface of the first circuit pattern, the lower surface facing the metal base substrate, the at least part of the side surface being adjacent to the lower surface.

An apparatus is disclosed for transferring a pattern of a composition containing particles of an electrically conductive material and a thermally activated adhesive from a surface of a flexible web to a surface of a substrate. The apparatus comprises: respective drive mechanisms for advancing the web and the substrate to a nip through which the web and the substrate pass at the same time and where a pressure roller acts to press the surfaces of the web and the substrate against one another, a heating station for heating at least one of the web and the substrate prior to, or during, passage through the nip, to a temperature at which the adhesive in the composition is activated, a cooling station for cooling the web after passage through the nip, and a separating device for peeling the web away from the substrate after passage through the cooling station, to leave the pattern of composition adhered to the surface of the substrate.

A printed circuit board according to an embodiment includes a first insulating layer; a first circuit pattern disposed on a lower surface or inside the first insulating layer; a second circuit pattern disposed on an upper surface of the first insulating layer; a second insulating layer disposed on the upper surface of the first insulating layer and surrounding the second circuit pattern; and a protective layer disposed on an upper surface of the second insulating layer, wherein the second insulating layer has at least one recess formed on its upper surface, and wherein the protective layer is disposed in the recess formed on the upper surface of the second insulating layer.

A printed circuit board according to an embodiment includes a first insulating layer; a first circuit pattern disposed on a lower surface or inside the first insulating layer; a second circuit pattern disposed on an upper surface of the first insulating layer; a second insulating layer disposed on the upper surface of the first insulating layer and surrounding the second circuit pattern; and a protective layer disposed on an upper surface of the second insulating layer, wherein the second insulating layer has at least one recess formed on its upper surface, and wherein the protective layer is disposed in the recess formed on the upper surface of the second insulating layer.

An insulated circuit substrate manufacturing method of the present invention includes a metal piece disposing step of disposing the metal piece in a circuit pattern shape on a resin material serving as the insulating resin layer and a bonding step of bonding the insulating resin layer and the metal piece by pressurizing and heating the resin material and the metal piece at least in a laminating direction. In the bonding step, the metal piece and the resin material are pressurized in the laminating direction by a pressurizing jig that includes a cushion material disposed on a side of the metal piece and a guide wall portion disposed at a position facing a peripheral portion of the cushion material, and the peripheral portion of the cushion material is brought into contact with the guide wall portion during pressurization.

A method is disclosed for applying an electrical conductor to a solar cell, which comprises providing a flexible membrane with a pattern of groove formed on a first surface thereof, and loading the grooves with a composition comprising conductive particles. The composition is, or may be made, electrically conductive. Once the membrane is loaded, the grooved first surface of the membrane is brought into contact with a front or/and back of a solar cell. A pressure is then applied between the solar cell and the membrane(s) so that the composition loaded to the grooves adheres to the solar cell. The membrane(s) and the solar cell are separated and the composition in the groove is left on the solar cell surface. The electrically conductive particles in the composition are then sintered or otherwise fused to form a pattern of electrical conductor on the solar cell, the pattern corresponding to the pattern formed in the membrane(s).