Today’s semiconductor market is highly competitive. Mobile application processors (APs) must continue to improve performance, even as devices get slimmer and more powerful. As on-device AI becomes more common, power use in smaller spaces increases, leading to higher power density and more heat. People still want longer battery life and thinner, lighter phones. Because of this, mobile APs need more than small performance upgrades; they need new designs that use space efficiently.
To address these issues, mobile AP packaging is evolving. It now does more than just protect the chip; it also manages heat and maximizes space. By improving package architecture and thermal dissipation, packaging maintains performance and reliability. It enables slimmer designs and larger batteries, making packaging increasingly critical for mobile APs.
When APs use more power to boost performance, temperature rises. Cooling them requires reducing power, which stops the chip from reaching its full potential. Now, controlling thermal resistance is key to a stable mobile AP design. Traditional solutions use heat-conductive materials or a thicker silicon die. As devices shrink, these methods alone are not enough to solve the heat problem.
The Shortcomings of Conventional PoP Designs
For high-end APs and SoCs, Package-on-Package (PoP) design is common to improve performance. In this design, DRAM sits on top of the AP chip. As mobile devices get thinner, so does the package, including the AP die. This reduces the path for heat to escape. Heat builds up faster, and the chip reaches its thermal limit sooner, which limits sustained peak performance.
When the AP is in operation, the heat generated by the silicon die inside the AP package must be quickly dissipated to reduce chip temperature. Lower thermal resistance improves heat dissipation efficiency, helping preserve stable performance even under high watt loads. To achieve this, device makers use heat-dissipation components, such as heat spreaders and vapor chambers, to transfer the heat generated by the AP to external cooling structures. However, in conventional POP structures, the DRAM package is positioned above the AP chip, limiting direct heat transfer between the AP and the heat dissipation components. This structural characteristic reduces heat transfer efficiency and acts as a basic limitation on performance improvements at both the package and system levels.
Samsung’s HPB addresses the need for steady performance improvements among mobile APs.
Samsung has improved thermal management by placing the heat path block (HPB) on top of the AP chip. This is the first time HPB has been used with Fan-Out Wafer-Level Packaging in the industry. It reduces thermal resistance within the package and maintains stable performance under heavy use.
This method creates a new package that moves heat from the AP die to the phone’s cooling parts more effectively. The DRAM package is now away from the main heat source, unlike in previous PoP designs. The HBM is placed directly above the heat source, helping heat escape more quickly and efficiently.
The HPB’s Core Benefits
Samsung created the HPB to efficiently remove heat from the AP die, maintain stable performance, and retain structural strength. They also introduced a new thermal interface material (TIM) with high thermal conductivity and strong bonding. This combination improves both heat dissipation and package reliability.
In a POP (package-on-package) structure, heat from the bottom AP (application processor) die must be transferred upward through the intermediate DRAM (dynamic random access memory) package. The heat transfer path passes sequentially through:
- the DRAM packages
- the bottom solder balls
- the substrate
- the DRAM die
- the EMC (epoxy molding compound)
Along this path, the solder balls, which have relatively high thermal conductivity, are distributed only in a limited region. The substrate dielectric layer, D-AF, used for die-stacking and EMC is composed entirely of low-thermal-conductivity materials. DRAM packages are inherently inefficient, limiting effective heat transfer to mobile device cooling components such as vapor chambers.
Unlike these materials, the HPB used in the Exynos 2600 is made of copper, which has a thermal conductivity of about 400 W/m·K. This is 500 to 1000 times better at transferring heat than the polymer materials used in substrates, DAF, or EMC. As a result, heat from the AP die quickly dissipates from the package, keeping temperatures lower at the source and helping maintain strong performance. This performance improvement is shaped not only by the materials but also by the evolution of the package’s design and development.
From Challenges to Breakthroughs: The Development Journey Shaping the Future of Samsung’s Mobile Packaging
To improve heat transfer from the AP die to the HPB, the new package design cut the DRAM package size by about half. It also adjusted both the overall package height and AP package thickness. These changes are intended to improve the thermal path without significantly increasing the package size.
Because of the asymmetric placement of the DRAM, Samsung reconfigured the AP DRAM interface. The overall chip and package architectures were also redesigned for performance and reliability. They pre-validated HPB thermal reduction through multi-perspective simulations. Target performance was achieved and sustained using root cause analysis and progressive optimization across materials, processes, and product stages. This progress was supported by close teamwork among departments.
Mobile processors must perform better while staying small. As a result, designing packages to manage heat will become even more important for stable AP performance. The HPB-based package shows how changing the heat transfer path can solve these problems.
By developing the HPB, Samsung Electronics has gained important technical know-how, testing methods, and a solid approach to team collaboration. With this foundation, the company plans to keep improving AP Packaging to deliver better performance, thermal stability, and spatial optimization in future mobile devices.
- Tags:Samsung
- Samsung Semiconductor
- Exynos 2600
- Samsung 2nm
- Mobile Processors
