A composite circuit board includes an insulation layer, an inner circuit layer, a first conductive layer and a second conductive layer embedded in the insulation layer, a third conductive layer and a fourth conductive layer formed on opposite surfaces of the insulation layer. The third conductive layer electrically connects with the first conductive layer. The fourth conductive layer electrically connects with the second conductive layer. The inner circuit layer is in a middle portion of the insulation layer. The first conductive layer and the second conductive layer respectively forms on opposite sides of the inner circuit layer. The insulation layer forms a plurality of first through holes between the first conductive layer and the inner circuit layer, a plurality of second through holes between the second conductive layer and the inner circuit layer.

A method for manufacturing a multilayer wiring board includes a step (1) and a step (2). The step (1) disposes a hole for through-hole, a squirt of metal foils, and a lower space. The squirt of the metal foils on both the sides of the insulating layer is formed at an opening of the hole for through-hole. The lower space is formed between the squirt of the metal foils and an inner wall of the hole for through-hole. The step (2) plugs up the hole for through-hole by forming an electrolytic filled plating layer at an inside of the hole for through-hole and on the metal foils on both the sides of the insulating layer. The plugging of the hole for through-hole in the step (2) is performed by once decreasing a current density of an electrolytic filled plating in a middle of the electrolytic filled plating and then increasing the current density again.

Method for electroplating a metal onto a flat substrate P. Surfaces are electrically polarized for metal deposition by feeding thereto at least one first and second forward-reverse pulse current sequences. The first forward-reverse pulse current sequence includes a first forward pulse generating a first cathodic current during a first forward pulse duration t.sub.f1 and having a first forward pulse peak current i.sub.f1, and a first reverse pulse generating a first anodic current during a first reverse pulse duration t.sub.r1 and having a first reverse pulse peak current i.sub.r1, the second forward-reverse pulse current sequence including a second forward pulse generating a second cathodic current during a second forward pulse duration t.sub.f2 and having a second forward pulse peak current i.sub.f2, and a second reverse pulse generating a second anodic current during a second reverse pulse duration t.sub.r2, the second reverse pulse having a second reverse pulse peak current i.sub.r2.

A method of making printed circuit board vias using a double drilling and plating method is disclosed. A first hole is drilled in a core, the first hole having a first diameter. The first hole is filled and/or plated with an electrically conductive material. A circuit pattern may be formed on one or two conductive layers of the core. A multilayer structure may then be formed including a plurality of cores that also include pre-drilled and plated via holes, wherein at least some of the pre-drilled and plated via holes are aligned with the first hole. A second hole is then drilled within the first hole and the aligned pre-drilled and plated holes, the second hole having a second diameter where the second diameter is smaller than the first diameter. A conductive material is then plated to an inner surface of the second hole.

The object of the invention is to provide a double-sided circuit non-oxide-based ceramic substrate excellent in radiation property and low in cost, and a method for manufacturing the same. A double-sided circuit non-oxide-based ceramic substrate related to the present invention includes a high heat-conductive non-oxide-based ceramic substrate that includes a through hole, a holding layer that is formed on a wall surface of the through hole, and an electro-conductive metal section that is held inside the through hole by the holding layer and does not include an active metal. The double-sided circuit non-oxide-based ceramic substrate related to the present invention preferably includes electrodes (thin film electrodes) that shield end surfaces of the holding layer and end surfaces of the electro-conductive metal section which are exposed to front and back surfaces of the ceramic substrate.

A multilayer wiring board having a high degree of freedom of wiring design and realizing high-density wiring, and a method to simply manufacture the multilayer wiring board is provided. A core substrate with two or more wiring layers provided thereon through an electrical insulating layer. The core substrate has a plurality of throughholes filled with an electroconductive material, and the front side and back side of the core substrate have been electrically connected to each other by the electroconductive material. The throughholes have an opening diameter in the range of 10 to 100 m. An insulation layer and an electroconductive material diffusion barrier layer are also provided, and the electroconductive material is filled into the throughholes through the insulation layer. A first wiring layer provided through an electrical insulating layer on the core substrate is connected to the electroconductive material filled into the throughhole through via.

A method for producing a via-filled substrate includes a metal film forming step of forming a metal film containing an active metal on a hole part wall surface of an insulating substrate having a hole part, a filling step of filling a conductor paste having a volume change rate before and after firing of 10 to 20% in the hole part in which the metal film is formed, and a firing step of firing the insulating substrate in which the conductor paste is filled.

A method for manufacturing a transparent circuit board includes the following steps. A composite substrate including a conductive layer and a transparent insulating layer on the conductive layer is provided. A wiring groove is formed on the transparent insulating layer by laser ablation and a carbon black layer is formed on an inner wall of the wiring groove. The wiring groove penetrates the transparent insulating layer, the wiring groove extends toward the conductive layer to pass through a part of the conductive layer. A conductive wiring corresponding to the wiring groove is formed and fully fills the wiring groove. A black oxide treatment is performed on a surface of the conductive wiring facing away from the conductive layer to form a blackened layer. A transparent cover film is pressed on a side of the transparent insulating layer facing away from the conductive layer. The conductive layer is removed.

Method for electroplating a metal onto a flat substrate P. Surfaces are electrically polarized for metal deposition by feeding thereto at least one first and second forward-reverse pulse current sequences. The first forward-reverse pulse current sequence includes a first forward pulse generating a first cathodic current during a first forward pulse duration t.sub.f1 and having a first forward pulse peak current i.sub.f1, and a first reverse pulse generating a first anodic current during a first reverse pulse duration t.sub.r1 and having a first reverse pulse peak current i.sub.r1, the second forward-reverse pulse current sequence including a second forward pulse generating a second cathodic current during a second forward pulse duration t.sub.f2 and having a second forward pulse peak current i.sub.f2, and a second reverse pulse generating a second anodic current during a second reverse pulse duration t.sub.r2, the second reverse pulse having a second reverse pulse peak current i.sub.r2.

A multilayer wiring board having a high degree of freedom of wiring design and realizing high-density wiring, and a method to simply manufacture the multilayer wiring board is provided. A core substrate with two or more wiring layers provided thereon through an electrical insulating layer. The core substrate has a plurality of throughholes filled with an electroconductive material, and the front side and back side of the core substrate have been electrically connected to each other by the electroconductive material. The throughholes have an opening diameter in the range of 10 to 100 m. An insulation layer and an electroconductive material diffusion barrier layer are also provided, and the electroconductive material is filled into the throughholes through the insulation layer. A first wiring layer provided through an electrical insulating layer on the core substrate is connected to the electroconductive material filled into the throughhole through via.