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High-density three-dimensional (3D) packaging technology for a CCD micro-camera system module has been developed by applying high-density interconnection stack-unit modules that have fine-pitch flip-chip interconnections within copper-column-based solder bumps and high-aspect-ratio sidewall footprints for vertical interconnections. Copper-column-based solder bump design and underfill encapsulation resin characteristics were optimized to reduce the strain in the bump and to achieve fine-pitch flip-chip interconnection with high reliability. High-aspect-ratio sidewall footprints were realized by the copper-filled stacked vias at the edge of the module substrate. High-precision distribution of sidewall footprints was achieved by laminating the multiple stack-unit substrates simultaneously. The fabricated three-dimensional package has operated satisfactorily as the CCD imaging data transmission circuit module. The technology was confirmed to be effective for incorporating many devices of different sizes at far higher packaging density than it is possible to attain using conventional technology.