Laminate circuit board with a multi-layer circuit structure

摘要

A laminate circuit board with a multi-layer circuit structure which includes a substrate, a first circuit metal layer, a second circuit metal layer, a first nanometer plating layer, a second nanometer plating layer and a cover layer is disclosed. The first circuit metal layer is embedded in the substrate or formed on at least one surface of the substrate which is smooth. The first nanometer plating layer with a smooth surface covers the first circuit metal layer. The second nanometer plating layer is formed on the other surface of the substrate and fills up the opening in the cover layer to electrically connect the first circuit metal layer. The junction adhesion is improved by the chemical bonding between the nanometer plating layer and the cover layer/the substrate. Therefore, the circuit metal layer does not need to be roughened and the density of the circuit increases.

主权项

1. A laminate circuit board with a multi-layer circuit structure, comprising:
a substrate, one of upper and lower surfaces of the substrate is a smooth surface; a first circuit metal layer, formed on the lower surface of the substrate; a second circuit metal layer, formed on the upper surface of the substrate; a first nanometer plating layer having a thickness between 5 to 40 nm, covering the first circuit metal layer which is enclosed between the first nanometer plating layer and the substrate; a second nanometer plating layer having a thickness between 5 to 40 nm, covering the second circuit metal layer which is enclosed between the second nanometer plating layer and the substrate; and a cover layer, formed on the substrate to cover the first nanometer plating layer on the first circuit metal layer and the second nanometer plating layer on the second circuit metal layer, wherein each of the first circuit metal layer, the second circuit metal layer, the first nanometer plating layer and the second nanometer plating layer has a smooth surface which has a roughness defined by Ra (Arithmetical mean roughness)<0.35 μm and Rz (Ten-point mean roughness)<3 μm and not recognizable by cross-sectional examination through an optical microscope of 1,000 magnifications.