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AssigneeMatsushita Electric Works, Ltd.
InventorsHirokazu Yoshioka, Norio Yoshida, Kenichiro Tanaka
Estimating the term…
A multilayer printed wiring board is formed with a plurality of conductor layers laminated as a whole with insulating layers interposed, a non-penetrating via hole provided in the insulating layer as bottomed by the conductor layer exposed, a plated layer provided inside the via hole for electric connection between the conductor layers, the via hole 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, whereby the equipotential surfaces occurring upon plating the plated layer are curved along the continuing zone to unify the density of current for rendering the plated layer uniform in the thickness without being thinned at the continuing zone.
A multilayer printed wiring board in which a plurality of conductor layers are laminated as a whole with insulating layers interposed, a non-penetrating via hole is provided in the insulating layer as bottomed by each conductor layer exposed, and a plated layer is provided inside the via hole for electric connection between the conductor layers, characterized in that the via hole is formed to have, at least at a continuing zone of inner periphery to bottom surface, a concave curved surface of a radius of more than 20 um in axially sectioned view of the via hole.
A method for manufacturing a multilayer printed wiring board in which a plurality of conductor layers are laminated as a whole with insulating layers interposed, a non-penetrating via hole is provided in the insulating layer as bottomed by each conductor layer exposed, and a plated layer is provided inside the via hole for electric connection between the conductor layers, characterized in that the via hole is formed in the insulating layer by irradiating to the insulating layer a carbon dioxide gas laser of a pulse width in a range of 1 to 100 μs, so as to have, at least at a continuing zone of inner periphery to bottom surface, a concave curved surface of a radius of more than 20 μm in axially sectioned view of the via hole.
Dependencies are inferred from the claim text.