[News] SK hynix Reportedly Completes 12-High Hybrid Bonding HBM Validation, Raises Yields for Mass Production

SK hynix’s yields for hybrid bonding HBM have reportedly improved, although the company did not disclose specific figures. According to The Elec, Kim Jong-hoon, Technical Leader at SK hynix, said validation of its 12-high HBM using hybrid bonding has been completed, adding that the company is now working to raise yields for mass production. While exact numbers were not provided, he indicated the company is significantly better prepared than it was two years ago.

As the report notes, the industry expects hybrid bonding to be adopted starting with HBM4, with gradual introduction likely from the second half of 2026 or into 2027 as 16-high products are commercialized.

However, the report notes that hybrid bonding still faces economic challenges under current technical conditions. SK hynix plans to further advance its mass reflow–molded underfill (MR-MUF) technology to meet customer demand ahead of fully adopting hybrid bonding, and has secured capabilities to meet height standards for up to 16-high stacks based on HBM3E.

As HBM continues to evolve, the number of stacked layers increases, significantly adding to process complexity. Packaging technologies have advanced in step, progressing from thermal compression non-conductive film (TC-NCF) to MR-MUF and now to hybrid bonding. With each generation, warpage has been reduced and productivity improved, the report notes.

Both TC-NCF and MR-MUF use small metal bumps between DRAM dies, combined with heat and pressure through thermal compression. The report adds that MR-MUF differs by addressing the warpage and damage issues seen in TC-NCF, using a protective material such as flux.

Equipment Orders Signal Hybrid Bonding Progress

Meanwhile, a separate report from The Elec in early April, citing sources, notes that SK hynix ordered a hybrid bonding inline system last month, jointly developed by Applied Materials and Besi. The system is said to cost around KRW 20 billion (approximately USD 15 million) and combines Applied Materials’ chemical mechanical polishing (CMP) and plasma processing tools with Besi’s hybrid bonder. The purchase marks SK hynix’s first acquisition of hybrid bonding equipment intended for mass production.

The report adds that, in addition to the inline system from Applied Materials and Besi, SK hynix plans to soon bring in hybrid bonding equipment developed by Hanwha Semitech for quality testing.

Samsung Electronics has also introduced Besi equipment for development purposes and is reportedly conducting quality tests using additional hybrid bonders from SEMES. However, the report notes that the SEMES tools are considered less mature.

Read more

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(Photo credit: SK hynix)