Faster computing, larger data volumes, and higher levels of integration. In the AI era, semiconductors continue to push the limits of performance.

However, high-performance semiconductors are not defined by chips alone. Packaging materials technologies that precisely connect chips to chips and chips to substrates, while protecting them reliably, also play a critical role. Among these materials, PID (Photo Imageable Dielectric) enables ultra-fine circuitry and is expanding what semiconductor packaging can achieve.

In this interview, we spoke with LG Chem’s PID R&D team to learn more about the current state and future direction of PID technology, as well as the team’s ongoing efforts to address the needs of next-generation semiconductor packaging.

Hello! Could you briefly introduce your team and your current role?

Hello. LG Chem’s Patterning Materials Project Team develops materials for *HDFO (High-Density Fan-Out) packaging technologies used in AI, HPC (High-Performance Computing), and 5G and 6G applications.

Our team is currently developing PID (Photo Imageable Dielectric), which is used in the *RDL (Redistribution Layer) within semiconductor packages. PID is a next-generation dielectric material that delivers low-loss performance and high reliability. It also offers excellent lithography performance, enabling extremely fine circuit patterns to be formed with high precision using light.

Specifically, our design efforts are focused on PSPI (Photosensitive Polyimide), a material used to form fine circuitry through light exposure. Thanks to its structural advantages, our PID delivers superior reliability over competing products by offering lower outgassing, lower shrinkage, and a lower curing temperature.

Based on these material design capabilities, the Patterning Materials Project Team is developing PID solutions that can support the increasingly precise and stable structures required for next-generation semiconductor packaging.

* HDFO (High-Density Fan-Out): An advanced packaging technology designed to enable more input/output (I/O) connections around semiconductor chips
* RDL (Redistribution ayer): A wiring layer that redistributes the input/output terminals of a semiconductor chip to desired positions for connection with external circuits
* PSPI (Photosensitive Polyimide): A polyimide material that reacts to light to form desired patterns and is used in semiconductor packaging processes
* PI (Polyimide): A high-performance polymer material with excellent heat and chemical resistance, used across semiconductors, electronic components, and other advanced industries

PID may be unfamiliar to general readers.
Could you explain what it is and what role it plays in semiconductor packaging?

PID is a photosensitive insulating material that undergoes a chemical reaction when exposed to light, allowing it to cure or dissolve. In semiconductor packaging, PID helps create pathways for electrical signals between chips and substrates while protecting circuits from signal interference and external impact.

It is especially important for implementing the ultra-fine circuitry required in high-performance semiconductors. Compared with conventional materials, PID can be cured at lower temperatures and offers strong adhesion to metal surfaces. Today, PID is being developed in two main forms: liquid type and film type. Liquid PID is applied and then cured, while film PID is attached as a thin film layer.

The role of PID becomes even more important in semiconductor packaging. Packaging is the final step that protects completed semiconductor chips and electrically connects them to external systems. In this process, PID serves as a protective insulating layer that prevents the fine electrical pathways connecting chips and substrates from short-circuiting. As a result, electrical signals can travel accurately and reliably through complex circuits without leaking or interfering with one another.

Put simply, PID plays a role similar to tunnels in a railway network connecting major cities. Just as tunnels and protective structures help trains move quickly and safely between cities, PID protects the pathways through which electrical signals travel, enabling accurate and fast signal transmission between chips and substrates.

As AI semiconductors become more advanced, packaging technologies are evolving rapidly. How are customer requirements for PID changing, and what liquid PID technologies is LG Chem developing in response?

As AI semiconductors continue to advance, semiconductor packaging technologies are also evolving quickly. In particular, the industry is shifting from conventional wire bonding, which connects semiconductor chips and substrates using fine metal wires, to flip-chip structures, where the chip is flipped and directly connected to the substrate. This transition is expanding the market for interlayer dielectric materials used in redistribution layers.

These changes are also reshaping the requirements for PID. In the past, precursor-type materials that formed the final polyimide structure through chemical reactions at high temperatures were widely used. However, high heat can place stress on semiconductors, and gases generated during the process can lead to defects.

More recently, pre-imidized polyimide compositions, which generate less gas during processing and can be cured at lower temperatures, are gaining attention for their processability and reliability. They help reduce defects while minimizing stress on semiconductors.

In addition, as AI semiconductors become thinner and more powerful, circuit lines are becoming extremely fine—many thousands of times thinner than a human hair. As a result, the importance of high-resolution PID capable of forming fine patterns continues to grow.

In line with these market changes, LG Chem is working to develop and supply next-generation PID materials that deliver process stability, reliability, and high-resolution patterning performance.

As the AI semiconductor market grows, requirements for packaging technologies and materials are changing rapidly. How are these changes being felt in the R&D field?
What led LG Chem to focus on film PID, and how do you view the future market?

The rapid growth of the AI semiconductor market is fundamentally changing the paradigm of semiconductor packaging. As a key material in this shift, PID is evolving beyond a material that simply insulates and protects circuits. It is now becoming a critical material that influences signal integrity, thermal management, and uniformity across large-area substrates for high-performance chips.

In the R&D field, AI semiconductor packaging is no longer viewed simply as an assembly technology. It is increasingly recognized as an area that requires highly advanced material property design. This is because chips that combine AI accelerators and HBM must withstand high power, high heat, high-frequency signals, and electromagnetic interference at the same time. As a result, customer requirements are becoming significantly more demanding.

[Key Requirements for PID in the AI Semiconductor Era]

• Compliance with environmental regulations: Development of environmentally conscious materials that do not use PFAS or organic solvents such as NMP and toluene, amid increasingly strict global environmental regulations
• Ultra-fine circuit implementation: Fine circuit formation through high-resolution patterning and low-temperature curing
• Process compatibility and yield improvement: Materials that offer strong adhesion and durability while enabling the use of existing lamination equipment

To address these changes, LG Chem has entered the PID market—historically led by Japanese materials companies—based on its proprietary technologies. The company is developing both liquid PID and film PID to target AI and high-performance semiconductor markets.

Liquid PID offers differentiated value in environmental performance and process stability, while film PID provides a solution capable of responding to diverse customer process environments. LG Chem is currently advancing development through collaboration with major global semiconductor companies.

Going forward, the semiconductor packaging market is expected to continue growing at a double-digit annual rate, driven by the expansion of AI infrastructure. As demand grows for advanced packaging technologies such as *CoWoS (Chip-on-Wafer-on-Substrate) and supply chains become more diversified, competition for materials optimized for next-generation packaging platforms such as glass substrates is expected to intensify. LG Chem aims to respond to these changes and strengthen its position in the next-generation semiconductor materials market.

*CoWoS (Chip-on-Wafer-on-Substrate): An advanced packaging technology that connects multiple semiconductor chips at high density on a single substrate to improve data processing speed and power efficiency

Glass substrates have recently become a major topic in the semiconductor substrate industry. Is LG Chem also preparing for this shift in substrate materials through next-generation film PID development?

The shift in semiconductor packaging from plastic-based organic substrates to glass substrates is one of the key factors being considered in next-generation film PID development. LG Chem and other leading materials companies are proactively developing film-type PID technologies that differ from conventional liquid PID in order to meet the physical properties and process requirements of glass substrates, including high flatness and low coefficient of thermal expansion.

As AI semiconductor performance increases, chips are becoming larger and stacked structures are becoming more complex. In these environments, conventional organic substrates can face limitations, including warpage during high-temperature processes and challenges in forming ultra-fine circuits. Glass substrates, by contrast, offer advantages for fine wiring and large-area formats due to their low coefficient of thermal expansion and highly flat surface.

[Key Requirements for Film PID in the Glass Substrate Era]

• Large-area uniformity: Since glass substrates are often produced in large rectangular panel formats rather than circular wafers, materials must maintain uniform thickness and properties across a wide area.
• Mechanical strength and elasticity: Film PID must offer high strength and elasticity to help compensate for the brittle nature of glass substrates and prevent cracking under repeated temperature changes.
• Process compatibility: Materials that can be used with existing lamination equipment without requiring additional equipment changes are preferred.

These requirements align closely with the strengths of film PID. In particular, uniformity in large-area processes and compatibility with existing processes are expected to become increasingly important as glass substrate adoption expands.

Many global companies are currently developing technologies for the commercialization of glass substrates and increasing related investments. If the adoption of glass substrates expands, the ability to respond to large-area processes and implement high-resolution patterning will become key competitive factors in the PID materials market.

Ultimately, LG Chem’s film PID development is not simply about developing a new material. It is a strategic effort to proactively respond to the next-generation packaging paradigm shift from plastic-based substrates to glass substrates. Moving forward, LG Chem plans to address the next-generation semiconductor packaging market with PID technologies that offer large-area uniformity and process compatibility.

LG Chem is developing both liquid PID and film PID. What are the key features and strengths of each product, and what differentiated value do they provide to customers?

LG Chem is building a complementary product portfolio consisting of liquid PID and film PID to address the diverse needs of the advanced semiconductor packaging market.

• Liquid PID: 
  LG Chem’s liquid PID is based on proprietary chemical design technology. It is well suited for forming extremely fine circuit patterns and is applied in a pre-imidized structure, which helps minimize gas generation during processing and reduce defect risks. It is also designed as an environmentally conscious material that excludes harmful substances such as PFAS and organic solvents.
• Film PID: 
  Film PID is applied through lamination, similar to attaching a thin film layer. It helps maintain consistent thickness even across large-area next-generation substrates. Because customers can use their existing equipment, it can reduce the burden of additional facility investment. It also combines strength and flexibility to help prevent cracking under temperature changes.

Based on this liquid PID and film PID portfolio, LG Chem provides optimized solutions tailored to customers’ process scale and production environments. Film PID can be proposed for customers that prioritize the use of existing facilities, while liquid PID can be proposed for customers that require ultra-fine circuit implementation and process stability.

We believe LG Chem’s strength in PID lies in its ability to provide optimal materials solutions aligned with each customer’s process characteristics and development direction.

Advanced semiconductor packaging materials require high precision and reliability. What was the most memorable technical challenge during PID development?

As an advanced semiconductor packaging material, PID must meet multiple requirements simultaneously, including diverse material properties and high reliability. For this reason, the development process involved many technical challenges. In the early stages, one of the greatest challenges was verifying the potential of a new material and securing competitiveness in a market already led by Japanese materials companies.

PID cannot excel in only one specific property. It must secure a balanced set of characteristics, including fine patterning capability, adhesion, heat resistance, process stability, and reliability. To achieve this, we designed the molecular structure of PI resins, applied various additives, repeatedly optimized process conditions, and continued analyzing and improving the root causes of technical issues.

Every stage brought new challenges, but the process of experiencing both small successes and failures became a source of growth for our team. The data and know-how accumulated through this continuous spirit of challenge ultimately became the foundation for securing excellent material properties and reliability in both liquid PID and film PID.

We believe R&D is not simply a process of finding the right answer. It is a process of continuously verifying possibilities and pushing beyond limitations. Based on accumulated technologies and experience, LG Chem will continue to take on the challenge of developing next-generation semiconductor materials that meet customer requirements.

Finally, what kind of future does LG Chem’s PID R&D team aim to build?

The future LG Chem’s PID R&D team aims to build is one in which we move beyond being a materials supplier and become a technology partner that helps drive the evolution of semiconductor packaging.

In response to the increasing integration and performance requirements of next-generation semiconductors such as AI chips and HBM, we will continue developing ultra-precise and highly reliable materials that can help overcome the limitations of existing processes.

Our goal is to combine our dual portfolio of liquid and film PID with AI-based process optimization technologies and new material development capabilities, enabling us to proactively identify and address customers’ customized needs through what we call a “Connecting Solution.”

In line with increasingly strict environmental regulations, we also aim to further advance PFAS-free materials and low-carbon material technologies that exclude harmful chemicals, contributing to a more sustainable semiconductor ecosystem.

Through continuous R&D and innovation, LG Chem will continue growing alongside customers and introducing materials that contribute to the advancement of the next-generation semiconductor industry.

In the AI era, semiconductor competitiveness is increasingly determined not only by the chip itself, but also by how precisely and reliably those chips are connected and implemented.

Based on its liquid PID and film PID technologies, LG Chem’s PID R&D team is expanding the boundaries of next-generation packaging technologies. From ultra-fine circuit implementation to readiness for next-generation glass substrates, the team is creating new possibilities for the future semiconductor industry through continuous research and challenge.

We look forward to the continued efforts of LG Chem’s PID R&D team as they work alongside customers to solve technical challenges and shape the future of next-generation semiconductor packaging.

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

1) CCL R&D Team: Driving Semiconductor Performance in the AI Era: An Interview with LG Chem’s CCL R&D Team

2) DAF R&D Team: The Hidden Enabler of Advanced Semiconductor Packaging: LG Chem’s DAF(Die Attach Film) R&D Team