The metal-clad laminate includes an insulating layer and a metal layer that exists in contact with at least one surface of this insulating layer. The insulating layer includes a cured product of a thermosetting resin composition that contains an epoxy compound having a number-average molecular weight of 1000 or less and at least two epoxy groups per molecule, a polyphenylene ether, a cyanate ester compound, a curing catalyst, and a halogen-based flame retardant. The halogen-based flame retardant is a flame retardant incompatible and dispersed in the thermosetting resin composition. The metal layer includes a metal substrate and a cobalt-containing barrier layer provided on at least a contact surface side of this metal substrate with the insulating layer. In the metal-clad laminate, the contact surface has, as surface roughness, a ten-point average roughness Rz of 2 m or less.

A circuit board according to an embodiment includes an insulating layer; and a lead pattern portion disposed on the insulating layer, wherein the lead pattern portion includes: a first portion disposed on the insulating layer; and a second portion extending from one end of the first portion; wherein the first portion is disposed overlapping the insulating layer in a vertical direction, wherein the second portion is disposed in an outer region of the insulating layer and does not overlap the insulating layer; and wherein the lead pattern portion has a centerline average roughness in a range of 0.05 ?m to 0.5 ?m or a 10-point average roughness in a range of 1.0 ?m to 5.0 ?m.

A surface-treated copper foil includes, on at least one surface of an untreated copper foil, a finely roughened layer formed of copper particles in which primary particles have a particle size of 10 nm to 110 nm or less, and a heat-resistant-treatment layer containing nickel and phosphorus, wherein a treated surface has a surface area ratio of 5.1 or more per 1 m.sup.2 of a two-dimensional area, the surface area ratio being calculated from a specific surface area measured by a krypton gas adsorption BET method, and a coating mass of the nickel is 2 mg or more per 1 m.sup.2 of a surface area.

High-speed interconnects for printed circuit boards and methods for forming the high-speed interconnects are described. A high-speed interconnect may comprise a region of a conductive film having a reduced surface roughness and one or more regions that have been treated for improved bonding with an adjacent insulating layer. Regions of reduced roughness may be used to carry high data rate signals within PCBs. Regions treated for bonding may include a roughened surface, adhesion-promoting chemical treatment, and/or material deposited to improve wettability of the surface and/or adhesion to a cured insulator.

The present invention provides a surface treated copper foil in which a dropping of the roughening particles from a roughening treatment layer provided on the surface of the copper foil is favorably suppressed and an occurrence of wrinkles or stripes when bonding with an insulating substrate is favorably suppressed. The surface treated copper foil, comprising a copper foil, and a roughening treatment layer on at least one surface of the copper foil, wherein a surface of the side of the roughening treatment layer of the surface treated copper foil satisfies one or more selected from the following items (1-1) to (1-8), and (1-1) a roughness Ra is 0.08 to 0.20 m, (1-2) a roughness Rz is 1.00 to 2.00 m, (1-3) a roughness Sq is 0.16 to 0.30 m, (1-4) a roughness Ssk is 0.6 to 0.35, (1-5) a roughness Sa is 0.12 to 0.23 m, (1-6) a roughness Sz is 2.20 to 3.50 m, (1-7) a roughness Sku is 3.75 to 4.50, (1-8) a roughness Spk is 0.13 to 0.27 m,
a glossiness of a TD of the surface of the side of the roughening treatment layer of the surface treated copper foil is 70% or less.

The present invention provides a surface treated copper foil in which a dropping of the roughening particles from a roughening treatment layer provided on the surface of the copper foil is favorably suppressed and an occurrence of wrinkles or stripes when bonding with an insulating substrate is favorably suppressed.

The surface treated copper foil comprises a copper foil, and a roughening treatment layer on at least one surface of the copper foil, wherein an aspect ratio of roughening particles of the roughening treatment layer satisfies one or more of the following items (1) and (2), the aspect ratio being a height of the roughening particles/a thickness of the roughening particles: (1) the aspect ratio of the roughening particles is 3 or less, (2) the aspect ratio of the roughening particles satisfies any one of the following items (2-1) or (2-2): (2-1) the aspect ratio of the roughening particles is 10 or less in the case that the height of the roughening particles is more than 500 nm and 1000 nm or less, (2-2) the aspect ratio of the roughening particles is 15 or less in the case that the height of the roughening particles is 500 nm or less; and a glossiness of a TD of the surface of the side of the roughening treatment layer of the surface treated copper foil is 70% or less.

A surface-treated copper foil is capable of imparting the profile shape of the substrate surface after removal of the copper foil, the profile shape maintaining fine wiring formability and achieving satisfactory adhesion of electroless copper plating coating. A resin substrate is provided with a profile shape of the surface maintaining fine wiring formability and achieving satisfactory adhesion of electroless copper plating coating. The surface-treated copper foil has a surface-treated layer formed on a copper foil, and the surface roughness Sz of the surface of the surface-treated layer is 2 to 6 m.

Such a metal foil is provided that a release layer is provided on a metal foil to enable physical release of a resin substrate, to which the metal foil is adhered, and thereby in the step of removing the metal foil from the resin substrate, the metal foil can be removed with good cost without damaging the surface profile of the metal foil transferred to the surface of the resin substrate, and also resins having different resin components can be adhered with good adhesion. A metal foil containing, on at least one surface of the metal foil, surface unevenness having a root mean square height Sq of from 0.25 to 1.6 m.

A substrate for a printed circuit board includes a base film having an insulating property; a first conductive layer formed on at least one of surfaces of the base film by application of a conductive ink containing metal particles; and a second conductive layer formed, by plating, on a surface of the first conductive layer, the surface being on a side opposite to the base film, wherein a region near an interface between the base film and the first conductive layer contains a metal oxide species based on a metal of the metal particles and a metal hydroxide species based on the metal of the metal particles, the metal oxide species in the region near the interface between the base film and the first conductive layer has a mass per unit area of 0.1 g/cm.sup.2 or more and 10 g/cm.sup.2 or less, and a mass ratio of the metal oxide species to the metal hydroxide species is 0.1 or more.

To provide a surface-treated copper foil that is capable of favorably decreasing the transmission loss even used in a high frequency circuit board and has an improved peel strength on adhering to an insulating substrate, such as a resin. A surface-treated copper foil containing a copper foil, and a surface treatment layer containing a roughening treatment layer on at least one surface of the copper foil, wherein on observation of the copper foil from the side of the surface having the roughening treatment layer, the roughening treatment layer has an average length of roughening particles of 0.030 m or more and 0.8 m or less, the roughening treatment layer has an average number of gap portions between the adjacent roughening particles of 20/100 m or more and 1,700/100 m or less, and the roughening treatment layer has a total frequency of an overlap frequency and a contact frequency of roughening particles of 120/100 m or less.