TOWA Contributes to AI Semiconductor Thermal Management and Productivity with ‘Mold Underfill (MUF)’ Technology via US-JOINT Platform

September 13, 2026

Resonac Japan

Overview

TOWA is accelerating customer concept validation through its ‘US-JOINT’ co-creation platform for next-generation semiconductor packaging technology. Addressing thermal management challenges in AI semiconductors, TOWA proposes Mold Underfill (MUF) technology, which uses compression molding under vacuum conditions to fill and seal gaps within packages with resin. This simplifies manufacturing processes, significantly boosts productivity, and dramatically improves heat dissipation, thereby enhancing the reliability of highly integrated AI semiconductors.

In Depth

Key Findings

TOWA is actively accelerating customer concept validation through its “US-JOINT” co-creation platform for next-generation semiconductor packaging technology. Addressing the critical thermal management challenges prevalent in rapidly evolving AI semiconductors, the company is strongly advocating for its Mold Underfill (MUF) technology. MUF is a process that utilizes compression molding under vacuum conditions to fill and effectively seal minute gaps within the semiconductor package with resin. This innovative approach simultaneously achieves simplification of manufacturing processes, a significant boost in productivity, and, most crucially, a dramatic improvement in heat dissipation, thereby making a substantial contribution to enhancing the reliability of highly integrated AI semiconductors.

Technical / Clinical Details

AI semiconductors, due to their escalating performance, generate heat far in excess of traditional semiconductors. Inefficient thermal management can lead to performance degradation, shortened lifespan, and even catastrophic failure of the chip. Conventional underfill solutions, primarily capillary flow underfill (CUF), rely on liquid resin infiltrating minute gaps via capillary action. This method suffers from limitations in flowability and a propensity for void formation. TOWA’s proposed Mold Underfill (MUF) technology fundamentally resolves these challenges. During the resin filling process between the semiconductor chip and the substrate, MUF applies compressive force in a vacuum environment, ensuring complete resin filling even in the most minute gaps and minimizing void formation to an extreme degree. The resins used in MUF are specially formulated with high thermal conductivity and low coefficients of thermal expansion (CTE), maximizing heat transfer efficiency from the chip to the substrate. This technology substantially reduces the thermal resistance within the package, consequently lowering the chip’s junction temperature and improving the overall reliability and performance of the device. Furthermore, compared to traditional CUF, MUF offers reduced process time and improved manufacturing yield, promising a significant increase in overall productivity.

Background & Context

AI semiconductors are rapidly increasing in importance across all sectors, including data centers, edge devices, and autonomous vehicles, with their performance evolving day by day. Particularly with the widespread adoption of heterogeneous integration packaging with stacked memories like HBM (High Bandwidth Memory), thermal management in packaging has become an element as critical as, if not more important than, chip design itself. Traditional packaging technologies are proving insufficient to meet these new thermal challenges, necessitating urgent development of novel materials and processes. TOWA’s MUF technology bridges this technological gap, reaffirming Japan’s strong technical capabilities in the semiconductor packaging industry. This represents a crucial strategic step for Japanese companies to establish a competitive edge in the AI era semiconductor race.

Strategic Significance & Outlook

TOWA’s Mold Underfill (MUF) technology is expected to find broad application not only in AI semiconductors but also in all high-performance semiconductors with significant heat generation, such as high-performance servers, 5G communication equipment, and Graphics Processing Units (GPUs). Going forward, TOWA will leverage its “US-JOINT” platform to expand collaborations with a wider range of customers, promoting the standardization and widespread adoption of MUF technology. Furthermore, ongoing research and development are anticipated to further enhance MUF resin materials (e.g., ultra-low CTE, ultra-high thermal conductivity) and develop technologies for finer pitch compatibility. This technology is poised to play a central role in resolving semiconductor packaging bottlenecks and accelerating the development of next-generation electronics.

Source: https://www.resonac.com/solution/column/013.html

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