Ibiden Company Limited

Masaki Ohno

Masanori Tamaki

A semiconductor mounting boardis prepared by electrically joining an IC chipvia an interposerof high rigidity to external padsand internal pads, which are formed on the uppermost surface of a build-up layer. When the IC chipgenerates heat, since padsare positioned away from the center, a large shearing stress is applied to the portions at which padsare joined to the interposerin comparison to the portions at which padsare joined to the interposer. Here, padsare formed at substantially flat wiring portions and thus when joined to the interposerby means of solder bumps, voids and angled portions, at which stress tends to concentrate, are not formed in the interiors of solder bumps. The joining reliability is thus high.

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Gifu, Japan

Masaki Ohno