PURPOSE: To easily form an interconnection to an upper layer and to realize the high density of interconnections in the upper layer by a method wherein an interconnection whose interconnection length is large is alloted to an upper layer away from a terminal layer, the utilization rate in the upper layer is increased by the small number of interconnections and interconnections to be extracted to the upper layer are reduced to a minimum.
CONSTITUTION: First-layer interconnection layers 2 and third-layer interconnections 4 are formed in the transverse direction in such a way that interconnections inside the interconnection layers are not overlapped in their thickness direction; second-layer interconnection layers 3 and fourth-layer interconnection layers 5 are formed in the longitudinal direction in such a way that interconnections inside the interconnection layers are not overlapped in their thickness direction. When the interconnections whose interconnection length is large are alloted to an upper layer away from a terminal layer, the interconnection density of the upper layer can be increased by the small number of interconnections, and the upper layer can be utilized effectively by a smallest bend or the smallest number of through holes. Thereby, when terminals 1 are situated in the lowermost layer, bends are reduced at both end points of a interconnection in order to extract the interconnection from the terminals 1 to the upper layer and the through holes are used little.
ISHII TAKEMOTO
SUZUKI KATSUKI
| JPH02222072A | 1990-09-04 | |||
| JPH01144649A | 1989-06-06 |