High‐density 3D packaging sidewall interconnection technology for CCD micro‐camera visual inspection system

Abstract

AbstractThe authors have developed 3D packaging sidewall interconnection technology, which enables a higher packaging density in the 3D stack direction, in order to realize a CCD micro‐camera visual inspection system integrated on the front of an experimental wireless micromachine for a visual inspection robot moving by itself in pipes of diameter 10 mm ϕ in an electric power generation plant. This technology was achieved by exposing the high‐aspect‐ratio circuit wiring layers at the edge of a stack‐unit substrate as sidewall footprint. The sidewall footprint has a high aspect ratio, which is a superior shape for the electrode terminals, by designing the Cu‐filled stacked vias to be laid out directly on the core substrate in a build‐up multilayer wiring substrate. With regard to the alignment between the stack‐unit substrates that determines the relative precision of the sidewall footprint, the process of dividing into the individual 3D packaging modules after multiple‐unit layout stack‐unit substrate lamination was used to improve the precision of sidewall footprint. By using this packaging technology, a prototype 3D packaging module consisting of a CCD video signal transmission circuit and a CCD control signal circuit in a CCD micro‐camera visual inspection system obtained an excellent CCD output signal and confirmed the effectiveness of the technology for high‐density packaging in a microspace. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(8): 67–75, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10063