Feature · 10 November 2026

TSMC now builds the logic layer inside SK hynix's AI memory

One part of TSMC's role in memory is confirmed, another rests on a single report, and Taiwan's own memory makers reported revenue up 347.9% on a year earlier.

For five generations of high-bandwidth memory, SK hynix made the stack's base die itself. With HBM4, it handed that job to TSMC. The company told reporters at TSMC's April symposium in San Jose that it produced the base die with its own process up to the fifth generation, and that for HBM4 it plans to use TSMC's advanced leading-edge logic process. The base die connects the stack to a GPU and controls it. "A key obstacle for AI technology today is a memory bottleneck," said Ahn Hyun, SK hynix's chief development officer. This part of the story is confirmed by the company. ³

The reason is that the base die stopped being a simple part. According to Korea's Herald Business, as relayed by TrendForce, SK hynix turned to TSMC because the dies took on greater logic and performance demands. Its HBM4, now in mass production, uses base dies made on TSMC's 12nm-class process. At TSMC's European forum, as reported by Tom's Hardware, HBM4E was described as using customizable base dies. Others are reported to be following. Micron's logic dies for HBM4E are expected to be made by TSMC, while Samsung makes its HBM4 base dies in-house on its 4nm foundry process. ⁴⁶

The arrangement has a price. Herald Business estimated that TSMC's HBM4 base dies could already cost 3–4 times more than SK hynix's core dies built on its 1b process. It added that passing the cost on to customers could prove difficult because long-term supply agreements account for a high share of HBM sales. It reported that SK hynix is considering Intel Foundry for part of its HBM4E base-die output. SK hynix said it was difficult to confirm details of its roadmap and that "some of the reports are not true." ⁴

The second strand is a single report and is not confirmed. The Information reported on November 6, 2026, citing two people familiar with the plans, that TSMC has begun drafting plans to make 3D DRAM at the request of Nvidia, its biggest customer. It also said TSMC is exploring buying a plant and converting it for memory production. TSMC did not address memory specifically. It said in a statement that it is focused "on our core business at all times" and described its mission as being "the trusted technology and capacity provider" of logic chips. Reuters could not independently verify the report, and Nvidia did not immediately respond to a request for comment. ¹⁷

Taiwan's own memory makers supply the same market. The four companies Taipei Ledger tracks in the group, Nanya Technology (2408), Winbond (2344), Phison (8299), Macronix (2337), filed combined revenue of NT$115.8bn for October 2026. That was +347.9% on a year earlier and +3.1% on the previous month, and the highest month in our data. None of the four appears in the reports above.

The year-to-date total makes the same point over a longer span. Combined revenue for January to October 2026 reached NT$810.3bn, a rise of +313.1% on the same months a year earlier. For the whole of 2025, the group's revenue was NT$257.5bn. Next on the calendar is the HBM4 family itself: Tom's Hardware reported that HBM4, HBM4E and C-HBM4E are on track to reach the market in 2026 and 2027. SK hynix has said it plans to begin mass production of HBM4 in 2026. ³⁶

Sources: 1. TSMC mulls making advanced AI memory chips: report - Taipei Times · 3. SK hynix unveils HBM4 roadmap at TSMC symposium - Aju Press · 4. SK hynix Reportedly Weighs Intel for HBM4E Base Dies amid TSMC Cost Pressure - TrendForce · 6. TSMC and GUC detail HBM4, HBM4E and C-HBM4E base dies - Tom's Hardware · 7. TSMC considers entering 3D DRAM at NVIDIA's request - Igor's Lab