Samsung said on Wednesday that it has manufactured a sample of a 16-stack high bandwidth memory (HBM).
During a local conference hosted by The Korean Microelectronics and Packaging Society, Samsung vice president Kim Dae-woo said the tech giant manufactured the chip with hybrid bonding around a week ago.
While it will take time for the 16-stack HBM to go into mass production, Samsung confirmed that it operated normally, he said.
The chip was made as HBM3 but Samsung plans to use a HBM4 to improve productivity, the vice president also added.
The tech giant was expected to only use hybrid bonding for one or two stacks of the chip due to alignment issues but applied the technique for all the stacks, sources said. The sample was made using equipment from Semes, Samsung’s fab equipment subsidiary.
Kim also said Samsung was mulling between using hybrid bonding or thermal compression non-conductive film for HBM4, which it will launch a sample for in 2025 and start mass production in 2026. The newly unveiled HBM3E uses TC-NCF.
Hybrid bonding can be more advantageous as they can add more stacks compactly without the need for through-silicon-via (TSV) which uses filler bumps to connect. The core die DRAM on the HBM can also become thicker with the same technique.
Chip standard setter JEDEC but HBM4’s size at 775 micrometers however so hybrid bonding may not be yet needed for the HBM4 form factor.
Kim also said mass reflow molded underfill was more productive than TC-NCF up to eight stacks but the latter had more advantages once stacks go 12 or above.
Customizing requests are expected to increase when HBM4 launches, the vice president also noted.
The buffer die will change to logic, so the die can come from Samsung or TSMC, he added.