A wiring substrate includes a first build-up part including an insulating layer and a conductor layer, and a second build-up part laminated on the first build-up part and including an insulating layer and a conductor layer. The minimum width and minimum inter-wiring distance of wirings in the first build-up part are smaller than the minimum width and minimum inter-wiring distance of wirings in the second build-up part. The insulating layer in the first build-up part includes resin and inorganic particles including first inorganic particles partially embedded in the resin and second inorganic particles completely embedded in the resin such that the first inorganic particles have first portions protruding from the resin and second portions embedded in the resin, respectively. The insulating layer of the first build-up part has a surface covered by the conductor layer and including a surface of the resin and exposed surfaces of the first portions.

A catalytic resin is formed by mixing a resin and either homogeneous or heterogeneous catalytic particles, the resin infused into a woven glass fabric to form an A-stage pre-preg, the A-stage pre-preg cured into a B-stage pre-preg, thereafter held in a vacuum and between pressure plates at a gel point temperature for a duration of time sufficient for the catalytic particles to migrate away from the resin rich surfaces of the pre-preg, thereby forming a C-stage pre-preg after cooling. The C-stage pre-preg subsequently has trenches formed by removing the resin rich surface, the trenches extending into the depth of the catalytic particles, optionally including drilled holes to form vias, and the C-stage pre-preg with trenches and holes placed in an electroless bath, whereby traces form in the trenches and holes where the surface of the cured pre-preg has been removed.

A catalytic resin is formed by mixing a resin and either homogeneous or heterogeneous catalytic particles, the resin infused into a woven glass fabric to form an A-stage pre-preg, the A-stage pre-preg cured into a B-stage pre-preg, thereafter held in a vacuum and between pressure plates at a gel point temperature for a duration of time sufficient for the catalytic particles to migrate away from the resin rich surfaces of the pre-preg, thereby forming a C-stage pre-preg after cooling. The C-stage pre-preg subsequently has trenches formed by removing the resin rich surface, the trenches extending into the depth of the catalytic particles, optionally including drilled holes to form vias, and the C-stage pre-preg with trenches and holes placed in an electroless bath, whereby traces form in the trenches and holes where the surface of the cured pre-preg has been removed.

A catalytic resin is formed by mixing a resin and either homogeneous or heterogeneous catalytic particles, the resin infused into a woven glass fabric to form an A-stage pre-preg, the A-stage pre-preg cured into a B-stage pre-preg, thereafter held in a vacuum and between pressure plates at a gel point temperature for a duration of time sufficient for the catalytic particles to migrate away from the resin rich surfaces of the pre-preg, thereby forming a C-stage pre-preg after cooling. The C-stage pre-preg subsequently has trenches formed by removing the resin rich surface, the trenches extending into the depth of the catalytic particles, optionally including drilled holes to form vias, and the C-stage pre-preg with trenches and holes placed in an electroless bath, whereby traces form in the trenches and holes where the surface of the cured pre-preg has been removed.

A wiring board includes an insulation layer made of ceramic, and a via conductor extending through the insulation layer in a thickness direction. The via conductor includes a metal portion and a ceramic portion. The metal portion includes a continuous phase disposed along the thickness direction of the insulation layer in a vertical cross-sectional view.

To provide a ceramic wiring board that may be thin, but have higher toughness, and have high connection strength to a wiring, an electronic device, and an electronic module. A ceramic wiring board (21) includes a ceramic sinter (211) containing an alumina crystal phase and a zirconia crystal phase as main components and containing manganese oxide and silica as auxiliary components, and a wiring (212) positioned in at least one of a surface or an inside of the ceramic sinter (211) and containing molybdenum as a main component. The zirconia crystal phase includes first crystal grains (211a) and second crystal grains (211b) having a larger grain size than the first crystal grains (211a), and the second crystal grains (211b) positioned at an interface between the ceramic sinter (211) and the wiring (212) include the second crystal grains entering a recess of the wiring (212).

The wiring board includes an insulation layer made of ceramic and a conductor layer extending in a planar direction inside the insulation layer. The conductor layer is constituted by a sintered body of a plurality of crystallites containing a metal as a main component, and has a layered structure in which a dense layer, a non-dense layer, and a dense layer are layered in layers in this order in a thickness direction.

A method for manufacturing a printed wiring board includes forming a resin insulating layer on a first conductor layer, forming a protective film on a surface of the insulating layer, forming an opening through the film and the resin insulating layer, removing the film, treating the surface of the insulating layer, forming a second conductor layer on the surface of the resin insulating layer, and forming a via conductor connecting the first and second conductor layers. The insulating layer includes resin and inorganic particles including first and second particles. The surface of the insulating layer includes a surface of the resin and substantially flat exposed portions of the first particles, and the forming the second conductor layer includes forming a seed layer by sputtering, forming a plating resist using DI exposure, forming an electrolytic plating layer, removing the resist, and removing the seed layer exposed from the electrolytic plating layer.

A coreless component carrier includes (a) a stack with at least one electrically conductive layer structure and at least one electrically insulating layer structure; and (b) a component embedded in the stack. At least one electrically insulating layer structure includes a reinforced layer structure, which is arranged at an outer main surface of the stack. Further described is a method for manufacturing such a coreless component carrier and preferably simultaneously a further coreless component carrier of the same type.

A printed wiring board includes a first conductor layer, a resin insulating layer including inorganic particles and resin, a second conductor layer including a seed layer and an electrolytic plating layer, and a via conductor connecting the first conductor layer and second conductor layer and including the seed layer and electrolytic plating layer extending from the second conductor layer. The inorganic particles include first particles, second particles, third particles and fourth particles formed such that the first and second particles are solid particles, the third and fourth particles are hollow particles, the first and third particles form an inner wall surface of the opening in the resin insulating layer, the second and fourth particles are embedded in the resin insulating layer, the first particles have shapes that are different from shapes of the second particles, and the third particles have shapes that are different from shapes of the fourth particles.