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US 8,263,878 B2Granted
Printed wiring board
AssigneeIbiden Co., Ltd.
InventorsYoshinori Takenaka, Takeshi Nakamura, Takamitsu Hattori
Life of this patent
Estimating the term…
Abstract
A printed wiring board disperses stress throughout an inner conductor layer, ensuring the flatness of a substrate. Embedding wires into the outermost insulating layer and forming the wires in a tapered shape that widens downward reduces the amount of stress applied on the edge of the inner conductor layer. This also prevents cracks from forming within the insulating layer, while maintaining favorable yield rates. Via diameters may also be reduced to increase circuit density.
Claims19
A printed wiring board, comprising:
- a first insulating layer having a first surface and a second surface on an opposite side of the first surface, the first insulating layer having a concave portion formed in the first surface and an aperture extending from the first surface to the second surface;
- a first conductor circuit formed in the concave portion of the first insulating layer, the first conductor circuit comprising a wiring having a width tapered from the first surface of the first insulating layer toward the second surface of the first insulating layer;
- a conductive pad formed on the second surface of the first insulating layer and configured to connect to an electronic device;
- a first via conductor formed in the aperture of the first insulating layer and connecting the conductive pad on the second surface of the first insulating layer to the first conductor circuit formed in the concave portion of the first insulating layer in the first surface of the first insulating layer;
- a second insulating layer having a first surface and a second surface on an opposite side of the first surface of the second insulating layer, the second insulating layer having a concave portion formed in the first surface of the second insulating layer and an aperture extending from the first surface of the second insulating layer to the second surface of the second insulating layer;
- a second conductor circuit formed in the concave portion of the second insulating layer, the second conductor circuit comprising a wiring having a width tapered from the first surface of the second insulating layer toward the second surface of the second insulating layer;
- and
- a second via conductor formed in the aperture of the second insulating layer and connecting the second conductor circuit formed in the concave portion of the second insulating layer in the first surface of the second insulating layer to the first conductor circuit formed in the concave portion of the first insulating layer in the first surface of the first insulating layer,
- wherein the second insulating layer is laminated to the first surface of the first insulating layer.
6 more elements
A printed wiring board, comprising:
- a first insulating layer having a first surface and a second surface on an opposite side of the first surface of the first insulating layer, the first insulating layer having a first concave portion in the first surface, a second concave portion in the second surface and an aperture extending from the first surface to the second surface;
- a first conductive circuit formed in the first concave portion of the first insulating layer, the first conductive circuit comprising a wiring having a width tapered from the first surface of the first insulating layer toward the second surface of the first insulating layer;
- a conductive pad formed in the second concave portion and configured to connect to an electronic device;
- and
- a first via conductor formed in the aperture of the first insulating layer and connecting the conductive pad formed in the second concave portion in the second surface of the first insulating layer to the first conductive circuit formed in the first concave portion in the first surface of the first insulating layer.
2 more elements
A printed wiring board, comprising:
- a first insulating layer having a first surface and a second surface on an opposite side of the first surface, the first insulating layer having a concave portion formed in the first surface and an aperture extending from the first surface to the second surface;
- a first conductor circuit formed in the concave portion of the first insulating layer, the first conductor circuit comprising a wiring having a width tapered from the first surface of the first insulating layer toward the second surface of the first insulating layer;
- a conductive pad formed on the second surface of the first insulating layer and configured to connect to an electronic device;
- and
- a first via conductor formed in the aperture of the first insulating layer and connecting the conductive pad on the second surface of the first insulating layer to the first conductor circuit formed in the concave portion of the first insulating layer in the first surface of the first insulating layer,
- wherein the conductive pad includes a protective film formed on an exposed surface of the conductive pad, and a solder member formed over the protective film.
3 more elements
Dependencies are inferred from the claim text.