Organic substrate (PCB) slip plane stress deflector for flip chip deivces

摘要

A flip chip integrated circuit package which provides stress relief for the solder bumps of the package. The package includes an integrated circuit that is mounted to a substrate. The integrated circuit is attached to a plurality of bond pads of the substrate by a number of corresponding solder bumps. The substrate has a first layer that is attached to a second layer. An area that is located between the layers and adjacent to the bond pads is left unattached so that a portion of the first layer can move independent of the remaining portion of the substrate. The unattached area allows the integrated circuit to "float" and expand at a different rate than the substrate when the package is thermally cycled.