As advanced packaging trends such as AI, HPC (High-Performance Computing), and *HBM continue to drive higher memory integration, the importance of semiconductor packaging technologies is growing across both DRAM and NAND manufacturing processes. As semiconductor chips become increasingly thinner and more complex, materials technologies capable of reliably managing heat and stress within the package are emerging as a key competitive advantage.

At the center of this evolution is DAF (Die Attach Film), an adhesive material that securely connects semiconductor chips to other chips, as well as chips to substrates. DAF plays a critical role in stabilizing chip attachment while maintaining semiconductor performance and reliability, making it an essential material in advanced semiconductor packaging.

In this interview, we spoke with LG Chem’s DAF development team to learn more about the role DAF plays in semiconductor packaging, the technological requirements emerging in the AI era, and the unique strengths that differentiate LG Chem’s DAF solutions.

* HBM(High Bandwidth Memory): A high-performance memory semiconductor used in AI semiconductors,
high-performance computing (HPC), and other advanced computing applications.

Hello! Could you briefly introduce your role and the DAF materials your team is developing?

Our team develops DAF (Die Attach Film), an adhesive material used in semiconductor packaging, as well as a variety of advanced process tapes for semiconductor packaging applications, including DCT (Dicing Tape), which is used during the wafer dicing process.

DAF is a key adhesive material that connects semiconductor chips to substrates, or chips to other chips. It must deliver excellent electrical and thermal reliability, making it an essential material in semiconductor packaging alongside *CCL and *EMC.

In addition, LG Chem’s DAF is designed to be integrated with DCT, which is required for the wafer dicing process. The combined solution is used throughout the packaging process—from cutting wafers into individual chips of the desired size to attaching those chips to substrates or other chips after dicing.

*CCL(Copper Clad Laminate): A core material used in semiconductor and PCB substrates
*EMC(Epoxy Molding Compound): An encapsulation material that protects semiconductor chips from external environments

What role does DAF play in semiconductor packaging?

DAF plays an important role in enabling high-density integration and high-performance semiconductor packages by allowing multiple semiconductor chips to be stacked securely during the packaging process.

Because DAF must firmly secure chips in their designated positions and maintain adhesion throughout subsequent thermal processes and reliability testing, it requires a high level of adhesive stability. It also helps relieve stress generated within the package, contributing to a stable package structure.

As DAF is applied in film form, it allows precise and uniform control of the adhesive layer thickness, which helps improve process stability. The DCT used alongside DAF supports the wafer during the dicing process and maintains the position of individual chips until the *Die Pick & Place process. Ultimately, while DAF is not visible within the finished semiconductor package, it serves as a critical material that helps keep semiconductor chips securely in place.

*Die Pick & Place: A process in which diced semiconductor chips are picked up and placed in designated positions

What are the key differences between conventional adhesives and DAF, and what technological changes
are required due to recent AI and high-performance semiconductor trends?

While conventional adhesives simply focus on bonding objects together, DAF (Die Attach Film) is a highly sophisticated adhesive material designed to stack semiconductor chips thinner than a human hair with absolute precision, while withstanding harsh semiconductor manufacturing processes and ensuring long-term reliability.

It must maintain stable pick-up properties to cleanly detach chips at the wafer stage, and form a uniform bonding layer without any micro-voids after attachment. Furthermore, to prevent delamination or cracking at the interface under high-temperature, high-humidity, or rapid thermal cycling conditions post-packaging, it requires advanced design technology that comprehensively controls properties such as Coefficient of Thermal Expansion (CTE) and modulus.

Recently, with the rise of AI servers and the HPC (High-Performance Computing) market, advanced packaging that stacks extremely thin semiconductor chips has become the norm, making DAF specifications far more demanding. As the gap between chips narrows, DAF must maintain perfect adhesion even at an “ultra-thin” thickness of 5μm or less, while “heat dissipation” performance to effectively release the heat generated by increased power consumption has emerged as an essential requirement.

To meet the challenging demands of “ultra-thinness” and “high heat dissipation,”
what unique technologies is the LG Chem DAF R&D team currently focusing on?

LG Chem’s DAF R&D team is focusing its capabilities on securing ultra-thin control technology and high-efficiency heat dissipation technology, which are the core themes of the advanced semiconductor market.

First, in the ultra-thin DAF field, we are advancing our proprietary nano-scale control technology to precisely regulate material viscosity, adhesion, and surface tackiness, ensuring uniform quality during chip stacking even as the film becomes extremely thin.

Second, in the high-heat-dissipation DAF field, we are developing technology to optimally utilize inorganic fillers, which are fine ceramic or metal particles with high thermal conductivity. Simply increasing the filler content to improve thermal conductivity makes the material highly viscous, reducing coatability and causing defects like voids between chips.

To overcome these limitations, LG Chem is integrating ▲our proprietary dispersion technology to mix fillers evenly without agglomeration, ▲a new catalyst system, and ▲our uniquely designed special resins to build customized, high-heat-dissipation DAF solutions that maximize thermal performance while delivering flawless process convenience.

*Filler: Fine particles added to improve the physical properties or functions of a material

What do you consider to be LG Chem’s key competitive advantages in DAF?
Are there any strengths that are particularly valued by customers?

LG Chem’s competitiveness in DAF can be summarized in three key strengths.

The first is our material design expertise. Over the past two decades, LG Chem has developed a wide range of DAF products in collaboration with global memory semiconductor manufacturers. Through this experience, we have accumulated extensive know-how in balancing material properties that often have competing requirements while optimizing performance for specific package structures and process conditions. In addition, by designing and supplying DCT solutions tailored to customer processes, we help reduce trial and error, shorten process optimization periods, and improve mass production yield and reliability.

The second is our film processing and precision coating technology. Through years of experience across various film businesses, LG Chem has built strong capabilities in film converting and precision coating technologies. Supported by automated measurement and inspection systems, we are able to consistently mass-produce films across a wide range of thicknesses, from thick films to ultra-thin films, while maintaining stable quality.

The third is our customer responsiveness. LG Chem maintains close communication with customers, responds quickly to evolving requirements, and collaborates closely from the development stage through mass production implementation. In particular, we have established an internal pre-validation system that replicates customer processes and work closely with our analytical research center as well as DX and simulation teams. This collaborative framework enables us to rapidly analyze technical issues that may arise during development and mass production and provide effective solutions.

LG Chem aims to be more than a supplier of semiconductor packaging materials. We strive to be a trusted partner that works alongside customers to address new development needs and solve process challenges together.

DAF is available in a variety of product types depending on the application and package structure.
What types of semiconductor packages and processes are they used in,
and which areas are seeing the strongest demand growth?

The Normal type is designed for general-purpose semiconductor packages and is widely used in a variety of applications, including DRAM and NAND, based on its balanced adhesion performance and processability. The *FOW (Film on Wafer) and *FOD (Film on Die) product families are applied in package structures that embed NAND controllers or wire connections.

The High-modulus type is a differentiated product category unique to LG Chem and is primarily used in mobile DRAM packages that incorporate thin wafers or *overhang structures. In these package designs, part of the chip extends beyond the chip underneath it. As a result, deformation or cracking can occur during wire bonding processes, where fine metal wires are used to connect semiconductor chips and substrates. To provide stable support for these structures, materials with high stiffness are essential.

As mobile devices continue to become thinner and more highly integrated, the adoption of these package structures is increasing, driving growing demand for High-modulus DAF. In addition, as markets for AI accelerators, servers, and on-device AI semiconductors continue to expand, demand for thermal management DAF solutions is also expected to increase as the industry seeks to address heat dissipation challenges.

*FOW(Film Over Wire): A process in which film is attached at the wafer stage
*FOD(Film Over Die): A process in which film is attached directly onto individual semiconductor dies
*Overhang Structure: A package structure in which part of a chip extends beyond the edge of the substrate or underlying chip

DAF is known to require highly precise process technologies. What are the most critical manufacturing processes,and what factors have the greatest impact on product quality?

As a thin-film material, DAF requires a high level of precision throughout the manufacturing process.

The first critical step is the *milling process, where the uniform dispersion of components such as resins and fillers is essential. Because DAF is applied in extremely thin layers, even slight inconsistencies in material composition can lead to localized variations in material properties. This may result in bonding defects, void formation within the bond line, or reduced reliability. For this reason, precise control of particle dispersion, agglomeration, and viscosity stability is critical to achieving uniform material properties across the entire film.

The coating process is another key factor. Beyond simply achieving the target thickness, it is important to secure both visual quality and processability. Surface defects or thickness variations can lead to failures during subsequent chip attachment processes. As a result, coating conditions, drying parameters, and production speed must be carefully controlled to ensure uniform material application and stable product quality. In particular, optimizing a wide range of process variables is essential to meeting the appearance and quality standards required by customers.

Ultimately, differences in DAF quality are not determined by any single process. Rather, they depend on how consistently quality is maintained throughout the entire manufacturing chain—from material formulation and dispersion to coating. Our team systematically manages and optimizes these process variables to deliver products that can be applied as reliably as possible in customer manufacturing environments.

*Milling: A process that finely disperses and mixes raw materials such as resins and fillers to ensure uniform material quality.

Looking back on the development of DAF, is there a particularly memorable moment that stands out?

One of the most memorable moments was seeing the DAF products we developed successfully reach mass production after LG Chem first entered the semiconductor packaging materials business. We were honored to receive the *Jang Young-sil Award twice for our High-modulus DAF and FOD products.

Throughout the process of developing products that could compete at the highest level in the market, we encountered numerous technical challenges. Working together with colleagues to solve each issue step by step was both highly engaging and deeply rewarding.

One project that remains especially memorable was the development of a DAF solution capable of supporting ultra-thin wafers while preventing breakage during manufacturing processes. At the time, we even drew inspiration from a simple paper backing board used to support thin sheets of paper as we explored potential approaches and development directions.

After many rounds of trial and error, we provided a High-modulus DAF sample to a customer for evaluation. When the product demonstrated excellent performance not only in our internal assessments but also in the customer’s evaluation, it gave us confidence that our development approach was on the right track. More importantly, it was the moment when we felt we had earned the customer’s technical trust, making it one of the most rewarding experiences of the entire development process.

*Jang Young-sil Award: A prestigious Korean award recognizing outstanding technologies and products that contribute to the advancement of industrial technology.

As a developer of DAF, which plays an important role in technologies ranging from AI servers and smartphones to automotive applications,has there been a particularly rewarding moment for you?

One of the most rewarding moments as a developer was seeing a product I helped develop being adopted in a global flagship smartphone.

In particular, I was amazed when I first saw a recently released foldable smartphone. Compared with early-generation models, its thickness had been reduced by nearly half. During the development of our new DAF product, we spent considerable time exploring ways to reduce thickness by a similar margin while maintaining existing performance levels, going through countless rounds of trial and error along the way. Seeing the product successfully applied in mass production was an incredibly rewarding experience.

I believe that new technologies and products are created through the collective efforts of engineers and developers across many different fields, each working to reduce thickness, improve performance, and overcome technical limitations within their own areas of expertise.

What I find most meaningful is knowing that the technologies we develop ultimately contribute to making people’s lives more convenient and creating a better world. That sense of purpose continues to be one of the most rewarding aspects of our work.

Lastly, is there anything you would like to share with our readers?

Although DAF is a material that remains unseen inside semiconductor devices, it plays a critical role in connecting and securing chips while supporting the overall package structure that forms the foundation of semiconductor packaging.

To date, DAF remains one of the most proven adhesive materials used in semiconductor packaging. As advanced package architectures continue to evolve toward higher integration and thinner form factors, the importance of DAF is becoming even greater, as adhesion stability, thermal performance, and long-term reliability have a direct impact on overall device performance. We will continue to advance DAF technologies and contribute to the ongoing evolution of advanced semiconductor packaging, helping enable new technologies and emerging markets in the years ahead.

As the era of AI and high-performance semiconductors continues to accelerate, the importance of packaging materials technologies is expected to grow even further. As semiconductor performance increasingly depends not only on the chip itself but also on package architecture and material innovation, DAF is emerging as a key material that helps determine both semiconductor reliability and performance.

Leveraging its expertise in ultra-thin and high thermal conductivity DAF technologies, as well as advanced material design capabilities, LG Chem is responding to the rapidly evolving semiconductor market. Through close collaboration with customers, LG Chem will continue to contribute to next-generation semiconductor packaging innovations.

[Explore More from LG Chem’s Advanced Materials R&D Interview Series👉]

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