15.6 A 36GB 3.3TB/S HBM4 DRAM with Per-Channel TSV RDQS Auto Calibration and Fully-Programmable MBIST

LLM-based generative AI requires high-capacity and high-bandwidth memory. We propose an HBM4 with 2048 I/Os, 3.3TB/s bandwidth, and 36GB cube density. Core die uses the 6thgen. DRAM and the base die uses a 4nm Fin-FET process. TSV count and data window are doubled for high-frequency margin. tCCDRis improved via per-channel TSV-RDQS auto calibration, enhancing rank-to-rank access. PMBIST enables at-speed testing in CoW and SiP. The on-die WDQS skew cancellation ensures robust timing, enabling reliable highspeed operation and improved yield.