AI Semiconductors Heat Up: "Cooling Is Survival"... The Dawn of HBM's War Against Heat [Chip Talk]

The Higher the Stack, the More Heat Trapped in HBM
Focus Shifts from Speed to Thermal and Cooling Technology
Three Major Memory Companies Compete in Low-Power and Cooling Solutions

With the expansion of the artificial intelligence (AI) semiconductor market, the core focus of the high-bandwidth memory (HBM) competition is shifting from speed to thermal management. As graphics processing unit (GPU) performance rises rapidly and the number of HBM layers increases, heat generation has emerged as a key variable in the competitiveness of next-generation HBM technologies.

According to the semiconductor industry on May 30, global memory companies such as Samsung Electronics, SK hynix, and Micron have recently been focusing on securing cooling and power efficiency technologies in the development of next-generation HBM. This is because, beyond simply increasing data processing speeds, the ability to control heat effectively is directly linked to the performance of next-generation AI semiconductors.

In particular, AI semiconductor customers such as Nvidia and AMD have reportedly requested HBM suppliers to strengthen heat management and low-power design. As the performance of AI accelerators increases, both power consumption and heat generation rise; if heat is not properly managed, it can lead to performance degradation and stability issues. HBM, which is structured with stacked DRAM layers, has so far relied on dissipating heat through the core die to the outside.

Industry sources point out that the HBM heat issue is no longer a challenge solely for memory companies but is spreading as an issue across the entire AI semiconductor ecosystem. Recently, Nvidia's next-generation AI server GPUs have begun consuming power reaching around 1,000W per chip. As HBM, which is mounted with the GPU, is required to process more data at higher speeds, the burden of heat generation inevitably grows.

In particular, starting from the fifth-generation HBM (HBM3E), heat generation is expected to become a significant technological limitation. Due to the nature of the stacked structure, the higher the DRAM is stacked, the harder it becomes for internal heat to escape. As the industry moves toward next-generation products such as HBM4E and HBM5, the importance of thermal control is expected to grow even further.

Three Memory Giants Go All-In on Distinctive Thermal Solutions

Accordingly, the HBM competitive landscape is also shifting from conventional memory performance competition to advanced packaging and cooling technology competition. The foremost technology that memory companies are racing to develop for high-performance HBM is 'hybrid bonding.' Unlike traditional thermo-compression (TC) bonding, which uses micro-bumps (small protruding joints) between chips, hybrid bonding directly joins copper and the insulating layer without bumps. This allows for thinner chips and prevents heat from being trapped between the chips, resulting in greater thermal dissipation. Within the industry, it is expected that hybrid bonding will become increasingly preferred as HBM stacking height increases.

Each memory company is concentrating on developing its own low-power and cooling technologies, in addition to hybrid bonding. SK hynix recently unveiled its 'iHBM' cooling technology for next-generation HBM5. This method inserts cooling elements (ICE) inside the HBM package to create an additional heat dissipation pathway. SK hynix aims to respond to high-performance AI semiconductor environments by improving thermal resistance characteristics by more than 30% compared to existing methods.

Samsung Electronics is also applying its proprietary low-power design and hybrid bonding technology to next-generation HBM. The recently announced HBM4E product focused on improving energy efficiency and thermal resistance. Samsung Electronics revealed that, for the HBM4E (7th generation) 12-layer sample supply, "By integrating low-power design and optimized packaging structure technology, energy efficiency was improved by 16% and thermal resistance by more than 1% compared to previous models." According to the company's recently released semiconductor packaging technology roadmap, hybrid bonding may be introduced as early as HBM4E.

Micron is also accelerating its push into the AI server market, leveraging low-power HBM. Its representative technology is the silicon through-silicon via (TSV) trench cooling method. Silicon trench cooling carves fine grooves (trenches) into the silicon die of the AI accelerator chip, circulating cooling fluid through these channels to dissipate heat inside the chip. Micron has filed patents related to this technology and is focusing on securing long-term cooling solutions.

An industry insider said, "Low-power and thermal management technologies will be the core direction of HBM research and development going forward. In the past, boosting data transfer speeds and increasing stacking levels were key competitive factors, but from now on, the ability to efficiently control increased heat generation will determine product performance and yield."

This content was produced with the assistance of AI translation services.