US Patent No. 9,992,878

CIRCUIT BOARD AND METHOD OF MANUFACTURING THE SAME


Patent No. 9,992,878
Issue Date June 05, 2018
Title Circuit Board And Method Of Manufacturing The Same
Inventorship Mitsuhiko Sugane, Ichikawa (JP)
Akiko Matsui, Meguro (JP)
Takahide Mukoyama, Kamakura (JP)
Tetsuro Yamada, Kawasaki (JP)
Yoshiyuki Hiroshima, Nakano (JP)
Kohei Choraku, Yokohama (JP)
Assignee FUJITSU LIMITED, Kawasaki (JP)

Claim of US Patent No. 9,992,878

1. A circuit board comprising:two substrates having front surfaces and back surfaces, respectively, the back surfaces opposed to each other;
inter-layer insulating films on the front surfaces of the two substrates, respectively;
a dielectric, a first part of which is interposed between the back surfaces;
a first through hole extending through each of the two substrates from each of the inter-layer insulating films to each of the back surfaces, filled with a second part of the dielectric and facing the first part of the dielectric;
a second through hole extending through the two substrates from one of the inter-layer insulating films to the other one of the inter-layer insulating films;
a first conductor film extending on an inner surface of the first through hole;
a second conductor film covering over the first through hole on each of the front surfaces, the second conductor film connected to the first conductor film on the each of the front surfaces; and
an electro-copper plating film extending on an inner surface of the second through hole, wherein
the dielectric has a higher dielectric constant than that of the inter-layer insulating films,
the first conductor film and the second conductor film of each one of the two substrates are each one of a pair of electrodes for a capacitor, andthe first conductor film has a part exposed to the first part of the dielectric, and the part of the first conductor film is not in connection with any other conductors including the electro-copper plating film.