Arranging I/O in a matrix array over the core circuitry of an IC generally provides 5-10 times more I/O than the traditional method of restricting pads to the periphery. This approach also minimizes overall die size. This method was pioneered by IBM over thirty years ago and has recently become attractive for new designs requiring several hundred I/O. In this paper we describe the development of a new area-array pad router which differs from other approaches in that no additional metal layer is added (unless needed) and no redistribution is required. We describe the design guideline definition, data preparation, pad placement, pad assignment, pad routing, and output padframe generation of this technique. The results of applying this router are shown for sample designs requiring 112, 298 and 485 I/O.