To accelerate prototyping designs, we propose a new Symmetric and Programmable MCM (SPMCM) substrate, which consists of 'a symmetrical array of slots for bare-chip attachment and Field Programmable Interconnect Chips (FPICs) for substrate routing. Especially, the FPIC that we developed contains two kinds of polygonal routing modules and some virtual-wires to reduce the number of routing switches and pin count. For a bare-chip slot with 2n pads, the number of switches used in the polygonal routing module is less than the conventional routing module by m J 4 times, where the flexibility ratio T F~ is close to 1. 0-7803-5650-0/99/$10.00 0 1999 IEEE