Implementing a 2-Gbs 1024-bit ½-rate low-density parity-check code decoder in three-dimensional integrated circuits

A 1024-bit, 1/2-rate fully parallel low-density parity-check (LDPC) code decoder has been designed and implemented using a three-dimensional (3D) 0.18 mum fully depleted silicon-on-insulator (FDSOI) CMOS technology based on wafer bonding. The 3D-IC decoder was implemented with about 8M transistors, placed on three tiers, each with one active layer and three metal layers, using 6.9 mm by 7.0 mm of die area. It was simulated to have a 2 Gbps throughput, and consume only 260 mW. This first large-scale 3D application-specific integrated circuit (ASIC) with fine-grain (5mum) vertical interconnects is made possible by jointly developing a complete automated 3D design flow from a commercial 2-D design flow combined with the needed 3D-design tools. The 3D implementation is estimated to offer more than 10 xpower-delay-area product improvement over its corresponding 2D implementation. The work demonstrated the benefits of fine-grain 3D integration for interconnect-heavy very-large-scale digital ASIC implementation.