HBM stacking - TSV and mass reflow/thermocompression bonding
CHOKEPOINTThree firms control HBM stacking through proprietary TSV and bonding, and CoWoS integration requirements lock out new entrants for years.
DRAM die stacking with through-silicon vias; assembled via mass reflow or thermocompression bonding. Base die integrates into CoWoS interposer package for AI GPUs and accelerators. Samsung, SK Hynix, and Micron oligopoly; HBM4 commands 8-10x commodity DRAM premium.
What the evidence shows
SK Hynix uses MR-MUF; Samsung and Micron use TC-NCF, splitting HBM3E into two bonding approaches.
photoncap.netHanmi focused on TC bonders for HBM, a segment ignored by market leaders Besi and ASMPT.
newsletter.semianalysis.comHanmi Semi was the dominant supplier of mass reflow bonders to SK Hynix, the leading HBM player.
techinvestments.ioWho controls it
Where it sits in the stack
Takes in: Individual DRAM die (from HBM fab), TSV reveal CMP, TCB bonding tool, NCP underfill
Sends on: HBM memory stack (4-12 die high) with interposer base die
Related nodes
Full scorecard, owner shares, supply edges and the full tracked roster are in the desk letter.
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