Abstract: A printed wiring board has a substrate having a first surface and a second surface on both sides of the substrate. A cavity is provided on the first surface. The cavity caves in towards the second surface. Several bumps are formed in the cavity as protruding towards the first surface. An insulation layer is filled in the cavity. The bumps are isolated from one another by the insulation layer. The top of each bump that protrudes towards the first surface and a zone in the cavity and close to the top are exposed in the cavity without being covered by the insulation layer.

Abstract: The present invention provides a multilayer print circuit board having at least an inner print circuit pattern and an outer print circuit pattern which are laminated on a substrate through an insulation layer and being electrically connected to each other through a blind hole provided in the insulation layer. The insulation layer is composed of a resin insoluble in an oxidization agent and inorganic powder dispersed in the resin. The inorganic powder is soluble in the oxidization agent. The surface of insulation layer and the wall of the blind hole are roughed by the oxidization agent before the outer print circuit pattern is formed on the surface of the insulation layer by plating, whereby the inorganic powder exposed to the oxidization agent is melted therein, resulting in the roughed surface of the insulation layer and the wall of the blind hole.

Abstract: The present invention provides a multilayer print circuit board having at least an inner print circuit pattern and an outer print circuit pattern which are laminated on a substrate through an insulation layer and being electrically connected to each other through a blind hole provided in the insulation layer. The insulation layer is composed of a resin insoluble in an oxidization agent and inorganic powder dispersed in the resin. The inorganic powder is soluble in the oxidization agent. The surface of insulation layer and the wall of the blind hole are roughed by the oxidization agent before the outer print circuit pattern is formed on the surface of the insulation layer by plating, whereby the inorganic powder exposed to the oxidization agent is melted therein, resulting in the roughed surface of the insulation layer and the wall of the blind hole.

Abstract: The present invention provides a multilayer print circuit board having at least an inner print circuit pattern and an outer print circuit pattern which are laminated on a substrate through an insulation layer and being electrically connected to each other through a blind hole provided in the insulation layer. The insulation layer is composed of a resin insoluble in an oxidization agent and inorganic powder dispersed in the resin. The inorganic powder is soluble in the oxidization agent. The surface of insulation layer and the wall of the blind hole are roughed by the oxidization agent before the outer print circuit pattern is formed on the surface of the insulation layer by plating, whereby the inorganic powder exposed to the oxidization agent is melted therein, resulting in the roughed surface of the insulation layer and the wall of the blind hole.