Exploiting Chiplet Integration Technology for Fast High-Capacity DRAM Modules

As the end of Moore’s law approaches, chiplet integration technology (or chiplet technology) has emerged to revolutionize future semiconductor chip design. Chiplet technology provides unique advantages over 3-D-stacking technology, including a more cost-efficient and thermal-friendly integration of heterogeneous technologies. Although chiplet technologies have already begun to be used by the latest commercial chips, they have not been explored for commodity dynamic random access memory (DRAM) design yet. Harnessing its advantages for DRAM for the first time, this article evaluates the feasibility of chiplet-based DRAM architecture, considering various physical and electrical constraints imposed by a standard chiplet interface [i.e., universal chiplet interconnect express (UCIe)]. We further explore the DIMM architectures that simplify module packaging and assembly, leading to reductions in total die size and overall costs. The comprehensive cross-level analysis (i.e., device, circuit, chip, and system levels) shows that chiplet-based DRAM reduces t_RCD + t_CAS, latency-critical DRAM timing parameters, by 1.32×–1.39×, at the same energy consumption. In addition, a 1.39×–2.28× improvement in t_RRD is obtained. The reduced DRAM timing parameters improve the overall system performance by up to 8.8%–24.7% (geomean 3.4%–8.4%) in real-life benchmarks. The chiplet-based heterogeneous integration achieves a 1.27× higher chip-level yield compared with the monolithic chip, along with up to 10% reduction in overall cost compared with traditional DIMMs at emerging process technologies.