Why HBM4 Will Redefine AI Compute: Trends, Tech, and Market Outlook

High Bandwidth Memory (HBM) has overcome the traditional "memory wall" by delivering unprecedented bandwidth and capacity, becoming the most powerful auxiliary for AI chips. Current mainstream configurations are HBM3 and HBM3e, and the market is projected to exceed $10 billion in 2024, with a long product cycle that sees increasing per‑chip capacity and stack density.

Today’s HBM stacks use a "TSV+Bumping" approach combined with TCB (Thermal Conductive Bonding) for interconnection. As the number of stacked layers grows, thermal dissipation degrades and TCB can no longer meet performance needs. Samsung’s HBM4 is expected to replace TCB with a hybrid bonding solution that eliminates interconnect bumps and improves heat removal.

Hybrid bonding is the core technology for next‑generation 3D packaging. It can be implemented as wafer‑to‑wafer (W2W) or die‑to‑wafer (D2W). W2W, used in 3D NAND and exemplified by ChangXin Storage’s Xstacking, offers very high yield for large‑area wafers, while D2W is suited for lower‑yield, high‑value dies. The article anticipates that future HBM will adopt the W2W scheme to support the massive I/O counts and data rates required by AI accelerators.

These technological shifts create new opportunities for equipment manufacturers and material suppliers. The transition to hybrid bonding and the anticipated launch of HBM4 in 2026 will drive demand for advanced bonding tools, liquid‑epoxy molding materials with higher thermal conductivity, and supply‑chain support within China, accelerating the domestic ecosystem’s capability to serve AI‑driven workloads.