Enhanced Imager Chip Packaging for Automotive Applications

The development of an automotive qualified packaging technology for CMOS and CCD imager chips is described. A flip-chip-on-flex solution was developed. This package solution was demonstrated using a 1/3 inch optical format imager chip that was designed for use with conventional ceramic leadless chip carrier packaging. Overall package thickness is 1.39mm, with the complete back-side of the silicon substrate exposed and available for chip cooling. The flex is bonded to a glass substrate, which provides the optical access to the imager chip. The use of a transparent underfill material reduces the rate of moisture infiltration and reduces optical reflections within the package structure. The flex may be extended beyond the package to allow surface mounting of additional passive and active components, as well as interconnection to additional circuitry.