At the AI Semiconductor Forum in Seoul, Samsung Electronics detailed its plan to introduce hybrid bonding technology in its forthcoming HBM4 memory stacks. This innovative approach is designed to significantly reduce thermal resistance and enable a much wider memory interface, both of which are becoming increasingly vital as Artificial Intelligence and high-performance computing workloads drive demand for higher bandwidth and greater efficiency. Unlike existing methods that stack DRAM dies using microbumps and underfill materials, hybrid bonding enables direct copper-to-copper and oxide-to-oxide connections. The result is a thinner, more thermally efficient 3D memory stack that better dissipates heat and maintains signal quality at high data rates.
Traditional high-bandwidth memory arrangements stack DRAM dies atop a base logic die using through-silicon vias for vertical signal passage, with microbumps allowing horizontal connections between dies. However, as stack heights increase and data rates climb, microbumps become an electrical and thermal bottleneck. Hybrid bonding directly addresses these limitations by allowing interconnect pitches below 10 micrometers. Reducing pitch decreases resistance and capacitance, thereby boosting overall signal integrity and supporting faster, cooler operation. This promises substantial advantages in thermals and bandwidth, especially for computation-heavy fields like Artificial Intelligence and supercomputing.
While Samsung pursues hybrid bonding, SK hynix is developing an enhanced molded reflow underfill (MR-MUF) process for its own HBM4 stacks. This method aims to meet JEDEC´s stringent height requirements without the significant capital expenditure required for true 3D copper bonding equipment. By refining its MR-MUF process, SK hynix hopes to achieve performance comparable to hybrid bonding while avoiding the extra cost and clean-room space consumed by specialized lithography and alignment tools. Samsung could potentially mitigate these equipment expenses by leveraging Semes, its own equipment subsidiary, though it remains uncertain whether Semes will have production-ready hybrid bonding tools prepared for Samsung’s target manufacturing launch in 2026. If successful, Samsung´s adoption of hybrid bonding could secure a technological edge over competitors SK hynix and Micron in the cutting-edge HBM4 market.
