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.

A metal substrate includes a first insulating substrate, a second insulating substrate, a first metal layer, a second metal layer and a release layer. The first insulating substrate has a first modified surface and a second surface opposite to the first modified surface. The first metal layer faces the second surface. The release layer is bonded on the first modified surface. The second insulating substrate is bonded on a side of the release layer, such that the release layer is between the first modified surface and the second insulating substrate. The second metal layer is disposed on a side of the second insulating substrate, such that the second insulating substrate is between the release layer and the second metal layer. An original surface roughness of the first modified surface has a variation substantially less than 10% after the first modified surface is released from the release layer.

A metal substrate includes a first insulating substrate, a second insulating substrate, a first metal layer, a second metal layer and a release layer. The first insulating substrate has a first modified surface and a second surface opposite to the first modified surface. The first metal layer faces the second surface. The release layer is bonded on the first modified surface. The second insulating substrate is bonded on a side of the release layer, such that the release layer is between the first modified surface and the second insulating substrate. The second metal layer is disposed on a side of the second insulating substrate, such that the second insulating substrate is between the release layer and the second metal layer. An original surface roughness of the first modified surface has a variation substantially less than 10% after the first modified surface is released from the release 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.

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.

According to one aspect of the present disclosure, a cover film for a flexible printed circuit board includes: an adhesive layer; and a protective layer that is layered on a surface of the adhesive layer, wherein a lamination temperature range in which a ratio of a viscosity of the protective layer to a viscosity of the adhesive layer is five times or more is present within a temperature range of 50° C. or more and 150° C. or less.

A device includes an electrically conductive substrate, one or more intermediate layer(s) in contact with the electrically conductive substrate and/or one or more interconnect layer, and a surface mounted electrical component contacting the interconnect layer.

A circuit structure includes a first busbar constituted by a cladding material, a second busbar, an insulating member including an insulating portion located between the first busbar and the second busbar, and an electronic component provided on the first busbar and the second busbar so as to straddle the insulating portion. The electronic component has a connection terminal bonded to the first busbar.

A circuit structure includes a first busbar constituted by a cladding material, a second busbar, an insulating member including an insulating portion located between the first busbar and the second busbar, and an electronic component provided on the first busbar and the second busbar so as to straddle the insulating portion. The electronic component has a connection terminal bonded to the first busbar.