Abstract:
In a multilayer printed wiring board, insulating layers and conductor layers are alternately stacked, and the conductor layers are electrically connected through via holes arranged on the insulating layers. The via hole is formed to have a swell at least on a part of it, in a substantially vertical direction to a thickness direction of the insulating layer. External stresses, such as a force of impact when dropped, are suppressed to have an insulating substrate not to easily warp, and cracks, disconnection, and the like of the conductor circuit are prevented. Thus, deterioration of reliability and drop impact resistance of a mounting substrate can be reduced.
Abstract:
A base for multilayer wiring boards in which a conductive layer (112) forming a wiring pattern is provided on one side of an insulating base (insulating resin layer (111)), and an adhesive layer (113) for interlayer adhesion is provided on the other side, and a through hole (114) extending through the conductive layer, the insulating base, and the adhesive layer is filled with a conductive resin composition (115) for interlayer electrical connection. The diameter of the conductive layer portion (114b) of the through hole is smaller than those of the insulating base portion and the adhesive layer portion (114a). The electrical connection between the conductive resin composition and the conductive layer is ensured through the back (112a) of the conductive layer.
Abstract:
A multilayered printed circuit board comprising: a substrate (330) on which a conductive circuit (334) is formed; an interlayer insulating resin layer (350) formed on the conductive circuit (334); an opening (348) for forming a via hole (360) formed in the interlayer insulating resin layer (350); and another conductive circuit (358) including a via hole (360) and formed on the interlayer insulating resin layer (350), wherein the surface of the conductive circuit (334) is subjected to a coarsening process using etching solution containing cupric complex and organic acid, and stripe pits and projections are formed on the inner wall of the opening (348) for forming the via hole (360).
Abstract:
A method of producing a printed wiring board (3) comprising a mounting recess portion (1) for mounting an electronic part, a conductor pattern (7), and a heat-sink plate (6) arranged at the bottom of the mounting recess portion (1), characterized in that a conductor pattern (7) is formed on an insulating substrate (5); a heat-sink plate (6) is adhered to a lower face of a portion of the insulating substrate (5) forming the mounting recess portion; and a laser beam (2) is irradiated to an upper face of the portion (10) forming the mounting recess portion to form a mounting recess portion (1).
Abstract:
An opening is made in a resin (20) with a laser to form a viahole. A copper foil (22) etched into a thin film (3 νm) to lower the heat conductivity is used as a conformal mask, thereby making an opening (20a) in the resin (20) by fewer times of irradiation with a pulse laser beam. This prevents formation of any undercut in the resin (20) on which an interlayer resin-insulating layer is to be formed, enabling improvement in the connection reliability of the viahole.
Abstract:
A multilayer printed wiring board (11) is formed with a plurality of conductor layers laminated as a whole with insulating layers interposed, a non-penetrating via hole (3) provided in the insulating layer (2) as bottomed by the conductor layer (1a) exposed, a plated layer (4) provided inside the via hole (3) for electric connection between the conductor layers (1a,1b), the via hole (3) being formed to be of a concave curved surface of a radius in a range of 20 to 100 µm in axially sectioned view at continuing zone of inner periphery to bottom surface of the via hole (3), whereby the equipotential surfaces occurring upon plating the plated layer (4) are curved along the continuing zone to unify the density of current for rendering the plated layer (4) uniform in the thickness without being thinned at the continuing zone.
Abstract:
A multilayered wiring board using conductive pillars for the interconnection of wiring layers. Since through holes are bored in the via lands of the wiring layers of the multilayered wiring board, the stress applied between the conductive pillars and wiring layers can be released at the time of connecting the conductive pillars to the via lands. Since the external side face of each conductive pillar smoothly continues to the surface of the via land at the contact section between the conductive pillar and the via land, the notch effect is relieved. Therefore, the reliability of the interconnection is secured even when a stress is applied to the connections during the manufacturing of the multilayered wiring board, and the mounting of electronic parts, etc.
Abstract:
PROBLEM TO BE SOLVED: To provide a printed wiring board in which the connection reliability of a through hole conductor is high.SOLUTION: A through hole 28 forming a through hole conductor consists of a first aperture 28f and a second aperture 28s tapered toward the center side. The maximum diameter of a third aperture 28c interconnecting the first aperture and second aperture is larger than the diameter d2 at a minimum diameter portion 28fc of the first aperture, and the diameter d4 at a minimum diameter portion 28sc of the second aperture.