With Samsung Electronics set to undergo the final quality test for Nvidia's sixth-generation high-bandwidth memory (HBM4), the foundry (semiconductor contract manufacturing) division that produces the "logic die," which serves as the brain of HBM, is also providing full support. In step with the memory division, which is sharply increasing HBM4 output, the foundry division is expanding logic die wafer input and pushing yield to the maximum to establish a stable production system.
Starting with HBM4, advanced process technology is being introduced to the logic die that serves as the brain of HBM. The logic die of HBM4 is mounted at the bottom of HBM, which is made by stacking multiple DRAMs. The logic die is a key component that connects the stacked DRAM and the graphics processing unit (GPU), which handles computations in artificial intelligence (AI) semiconductors, controlling power delivery and data signals as a controller.
According to industry sources on Oct. 20, the 4-nanometer (nm, one-billionth of a meter) process yield for logic dies produced by the Samsung Electronics foundry division has exceeded 90%. A 90% logic die yield means more than 9 out of 10 logic dies produced with the 4 nm process are good products, indicating the technology is stable enough to begin mass production. As the Samsung Electronics memory division is mass-producing HBM4 samples to supply to customers such as Nvidia and AMD, the foundry division has reportedly increased logic die production to about half of the total capacity of its 4 nm lines and is operating accordingly.
Samsung Electronics uses its foundry division's 4 nm process to manufacture logic dies, while SK hynix uses TSMC's 12 nm-class process. Micron uses its own 12 nm-class DRAM process but applies the company's most advanced node. In general, the finer the semiconductor process, the higher the performance and the better the power efficiency. As each HBM generation requires higher performance than the previous generation and heat issues become more severe, memory semiconductor companies are applying advanced processes to the logic die, the core of HBM, starting with HBM4.
An industry official said, "The Samsung Electronics foundry division's 4 nm process is mature enough that overall process yield exceeds 80%. Logic die yield also exceeded 40% at the initial trial production stage early this year, showing stability," and added, "As the memory division has staked its fate on HBM4, the foundry division, which is responsible for producing the logic die that is central to HBM4, is also providing support."
The stable yield of the Samsung Electronics foundry division is seen as encouraging, as the era of "custom HBM" is expected to blossom starting with seventh-generation HBM (HBM4E). The industry expects that from HBM4E, the business of developing HBM optimized for the application of the AI semiconductor that a customer wants to install—"custom HBM"—will begin in earnest. To do this, it is important to design circuits on the logic die in the form desired by the customer and to have foundry process capabilities that can produce them to meet diversified demand.
An industry official explained, "Samsung Electronics applied a finer process to the HBM4 logic die ahead of competitors to make up for the slump in the previous generation," adding, "Although market validation remains, it is true that the importance of foundry process technology will be highlighted in the coming next-generation HBM market as well."