Abstract: There is provided a wiring substrate whose mechanical strength, water resistance, humidity resistance, and product yield can be improved. This wiring substrate includes a device region in which a main wiring pattern composed of a metal layer is embedded in an insulating layer; a peripheral region which surrounds a periphery of the device region and in which a dummy wiring pattern composed of a metal layer is embedded in an insulating layer; and an insulating boundary region interposed between the device region and the peripheral region, composed of an insulating layer. The insulating boundary region has a winding shape in which it is possible to draw a virtual straight line alternately traversing the metal layer constituting the dummy wiring pattern and the insulating layer constituting the insulating boundary region, parallel to an inscribed line of at least one side of an outer edge of the device region.

Abstract: There is provided a carrier-attached metal foil in which the metal layer is less likely to be released at the ends of the carrier-attached metal foil or in the cutting place(s) of a downsized carrier-attached metal foil, and moreover a decrease in the strength of the carrier is effectively suppressed. This carrier-attached metal foil includes a carrier; a release layer provided on the carrier; and a metal layer having a thickness of 0.01 ?m or more and 4.0 ?m or less provided on the release layer. The carrier has a flat region having a developed interfacial area ratio Sdr of less than 5%, and an uneven region having a developed interfacial area ratio Sdr of 5% or more and 39% or less, on at least a surface on the metal layer side, and the uneven region is provided in a linear pattern surrounding the flat region.

Abstract: Provided is a carrier-attached metal foil which has excellent carrier-releasability and excellent selective metal layer-etchability, and can achieve a reduction in transmission loss and resistance in a semiconductor package (for example, a millimeter-wave antenna substrate) manufactured using the same. The carrier-attached metal foil includes: (a) a carrier; (b) a release functional layer on the carrier and including (b1) an adhesion layer disposed closer to the carrier and having a thickness of more than 10 nm and less than 200 nm and (b2) a release assistance layer disposed farther from the carrier and having a thickness of 50 nm or more and 500 nm or less; and (c) a composite metal layer on the release functional layer and including (c1) a carbon layer disposed closer to the release assistance layer, and (c2) a first metal layer disposed farther from the release assistance layer and mainly composed of Au or Pt.

Abstract: Provided is a carrier-attached metal foil which has excellent carrier-releasability and excellent selective metal layer-etchability, and can achieve a reduction in transmission loss and resistance in a semiconductor package (for example, a millimeter-wave antenna substrate) manufactured using the same. The carrier-attached metal foil includes: (a) a carrier; (b) a release functional layer on the carrier and including (b1) an adhesion layer disposed closer to the carrier and having a thickness of more than 10 nm and less than 200 nm and (b2) a release assistance layer disposed farther from the carrier and having a thickness of 50 nm or more and 500 nm or less; and (c) a composite metal layer on the release functional layer and including (c1) a carbon layer disposed closer to the release assistance layer, and (c2) a first metal layer disposed farther from the release assistance layer and mainly composed of Au or Pt.