TentorTech

Samsung has announced plans to use hybrid bonding technology for its upcoming HBM4 memory to improve thermal performance and enable a wider memory interface. The company shared this strategy at the AI Semiconductor Forum in Seoul, South Korea. Meanwhile, reports suggest that rival SK hynix might delay adopting hybrid bonding, sticking with its current methods for now. High-bandwidth memory (HBM) stacks multiple memory dies on a base die, connected using microbumps and techniques like mass reflow with molded underfill (MR-MUF) or thermal compression with non-conductive film (TC-NCF). However, as HBM speeds increase and more DRAM devices are added, microbumps become a bottleneck, limiting performance and efficiency. Hybrid bonding offers a solution by directly connecting dies without microbumps, improving density, thermal performance, and reducing resistance. Despite its advantages, hybrid bonding is expensive and requires specialized equipment. While all major HBM manufacturers considered it for HBM3E, only Samsung and Micron opted for TC-NCF, while SK hynix stuck with MR-MUF. For HBM4, Samsung is pushing ahead with hybrid bonding, but SK hynix is developing an advanced MR-MUF technique as a backup. The high cost and space requirements of hybrid bonding tools make SK hynix cautious, especially if its improved MR-MUF can deliver similar performance and yields. Another reason SK hynix may delay hybrid bonding is that its advanced MR-MUF allows thinner HBM stacks, meeting JEDEC's HBM4 height requirements. If the company can comply with these specs using existing methods, hybrid bonding becomes less appealing. Samsung, on the other hand, benefits from having its own equipment supplier, Semes, which could help reduce costs—though it's unclear if Semes can produce the necessary hybrid bonding tools yet. If Samsung successfully qualifies HBM4 with hybrid bonding, it could gain a competitive edge in performance, thermals, and signal density. This might help Samsung reclaim market share from Micron and SK hynix when HBM4 enters mass production in 2026. The industry is watching closely, as hybrid bonding represents the future of memory stacking, and Samsung's move could reshape the HBM landscape.