A substrate for mounting a semiconductor element thereon includes a metal plate and columnar terminal portions composed only of plating layers and formed on one-side surface of the metal plate. The columnar terminal portions include, as an outermost plating layer, a roughened silver plating layer having acicular projections. The roughened silver plating layer has a crystal structure in which the crystal direction <101> occupies a largest proportion among the crystal directions <001>, <111> and <101>. The substrate for mounting a semiconductor element thereon can be manufactured with improved productivity owing to reduction in cost and operation time, and achieves remarkably high adhesion to sealing resin while keeping the total thickness of plating layers including the silver plating layer, which are to serve as terminals and the like, to be thin.

A circuit board pad resonance control system includes a board. A signal transmission line is included on the board. A plurality of connector pads are positioned on the board. A first connector pad receives the signal transmission line adjacent a first end of that connector pad. The first connector pad includes a mounting surface that mounts directly to a coupling element that is configured to couple a subsystem to the board, and reduces a resonance that is produced by an open portion of a signal transmission path that is created when the coupling element is directly mounted to the mounting surface of the first connector pad in a first orientation. In a specific example, the mounting surface may include a plurality of protrusions, a plated surface, and/or a mask that reduces the conductivity of the connector pad which reduces signal integrity issues due to resonance.

Surface-treated copper foils that exhibit a material volume (Vm) less than 1.90 m.sup.3/m.sup.2. Where the surface-treated copper foil is treated on the drum side and includes a treatment layer comprising a nodule layer. Such surface-treated copper foils can be used as a conductive material having low transmission loss, for example in circuit boards.

Surface-treated copper foils that exhibit a material volume (Vm) in a range of 0.05 to 0.6 m.sup.3/m.sup.2 and a yellowness index (YI) in a range of 17 to 52 are reported. Where the surface-treated copper foil is treated on the deposited side and includes a treatment layer comprising a nodule layer. Such surface-treated copper foils can be used as a conductive material having low transmission loss, for example in circuit boards.

Surface-treated copper foils comprising an electrodeposited copper foil including a drum side and a deposited side are reported. The treatment layer is disposed on one of the drum side and the deposited side and provides a surface-treated side. The treatment layer comprises a nodule layer and the surface-treated side exhibits a void volume (Vv) in a range of 0.1 to 0.9 m.sup.3/m.sup.2. The surface-treated copper foil also has a combined hydrogen and oxygen content of less than or equal to 300 ppm.

Surface-treated copper foils exhibiting a void volume (Vv) in a range of 0.4 to 2.2 m.sup.3/m.sup.2 and an arithmetic mean waviness (Wa) lower than or equal to 0.4 m are reported. Where the surface-treated copper foil is treated on the drum side and includes a treatment layer comprising a nodule layer. Such surface-treated copper foils can be used as a conductive material having low transmission loss, for example in circuit boards.

Surface-treated copper foils that exhibit a material volume (Vm) less than 1.90 m.sup.3/m.sup.2. Where the surface-treated copper foil is treated on the drum side and includes a treatment layer comprising a nodule layer. Such surface-treated copper foils can be used as a conductive material having low transmission loss, for example in circuit boards.

Surface-treated copper foils that exhibit a material volume (Vm) in a range of 0.05 to 0.6 m.sup.3/m.sup.2 and a yellowness index (YI) in a range of 17 to 52 are reported. Where the surface-treated copper foil is treated on the deposited side and includes a treatment layer comprising a nodule layer. Such surface-treated copper foils can be used as a conductive material having low transmission loss, for example in circuit boards.

A surface-treated copper foil of the present disclosure includes a copper foil substrate, at least one surface of which has a surface treatment coat including at least a roughening-treated surface on which roughening particles are formed. Observation of a cross-section of the surface-treated copper foil with a scanning electron microscope shows that on a surface of the surface treatment coat, a standard deviation of the particle height of the roughening particles is 0.16 m or more and 0.30 m or less, and an average value of the ratio of the particle height to the particle width (particle height/particle width) of the roughening particles is 2.30 or more and 4.00 or less.

A circuit board of the present disclosure includes a substrate, a conductor layer located on the substrate, a reflective layer located on the conductor layer, and a resin layer located on the substrate to be in contact with the conductor layer and the reflective layer. In a surface of the reflective layer, arithmetic mean roughness Ra obtained from a roughness profile is less than 0.2 m, and a ratio of kurtosis Rku obtained from a roughness profile to skewness Rsk obtained from a roughness profile is 5 or more and 15 or less.