Summary of Key Points
Intel and Lens Technology, a company that produces smartphone glass, have joined forces to explore the use of glass substrates for chip packaging. This move is driven by the increasing size and complexity of AI chips, which traditional packaging materials (organic substrates) can no longer handle effectively. Organic substrates are prone to deformation and lack the necessary circuit density. Glass substrates, on the other hand, are flatter, more stable, and can accommodate larger sizes, making them a perfect solution for these issues. However, glass substrate technology is still in its early stages, with key processes such as drilling and copper plating not yet fully matured. Industry leaders like Intel, Samsung, and SK are making early investments, but mass production is at least 3-5 years away, starting with high-value products like AI chips.
1. Growing AI Chips and the Limitations of Traditional Packaging Materials
AI chips have become increasingly complex, consisting of multiple computing cores, HBM memory, and various power components. The density of circuits has risen significantly, leading to larger packaging sizes (some AI chips require several times the area of regular CPUs).
Traditional organic substrates (made from resin and glass fiber) face several challenges:
- Deformation due to thermal expansion and contraction: Changes in temperature cause organic materials to expand and contract, leading to substrate warping. This can affect chip placement, welding, and signal transmission.
- Size limitations: Larger organic substrates are more prone to deformation, making them unsuitable for the large-scale packaging required by AI chips.
Glass substrates offer superior flatness and stability, with a thermal expansion coefficient that is closer to that of silicon, reducing the risk of deformation.
2. The Advantages of Glass Substrates: A Complementary Solution
Glass substrates are not intended to replace both organic substrates and silicon interlayers; rather, they aim to fill the gap between them:
- Advantages over organic substrates: They are flatter and more stable, capable of supporting larger packages and handling high-frequency, high-speed signals (essential for data transmission in AI chips).
- Advantages over silicon interlayers: While silicon interlayers have high circuit density, they are costly (produced using silicon wafers) and limited in size (up to 300 millimeters). Glass substrates can be made into larger panels, potentially at lower costs.
In summary, organic substrates will continue to be used for regular chips, while silicon interlayers will handle the most delicate connections between components. Glass substrates will be dedicated to the packaging of large, complex AI chips.
3. Lens Technology's Cross-Industry Transition: From Smartphone Glass to Chip Glass
Lens Technology’s transition to chip glass packaging is facilitated by its expertise in glass processing and its ability to produce high-precision glass in large quantities. However, it faces significant challenges:
- Quality requirements for chip glass: There must be no cracks, precise holes (as small as a few micrometers), and a strong copper layer that does not delaminate during thermal cycling.
- High standards: The failure of chip glass can result in the complete destruction of the expensive AI chip.
4. Key Challenges in Glass Substrate Technology
The core challenge is the TGV (Glass Through-Via) process, which involves drilling tiny holes in glass and depositing copper to enable electrical signal transmission. This process is extremely difficult:
- Drilling: Holes must be very small (5-10 micrometers in diameter) with a high aspect ratio (depth to diameter ratio of over 10), and the drilling must be precise to avoid cracks.
- Copper plating: Glass does not conduct electricity, so an adhesive layer must be applied before copper plating. Poor adhesion or issues with the plating process can lead to defects.
- Low yield: Producing defect-free glass substrates in large quantities is a major challenge, especially considering the high cost and complexity of the process.
5. Industry Progress and Mass Production Timelines
Industry players are actively developing glass substrate technology:
- Intel: Has been researching for 10 years and plans to introduce solutions in the second half of the 2020s.
- Samsung Electro-Mechanics: Has built a pilot line with the goal of mass production by 2027.
- SK Group’s Absolics: Received $100 million in funding from the U.S. government to establish manufacturing capacity.
However, mass production is still several years away, likely starting in 2026-2027. Glass substrates will not immediately replace all existing packaging materials; they will first be used in high-value, large-package products like AI chips and advanced GPUs.
In conclusion, glass substrates represent a new option for packaging technology in the AI era. Their success depends on overcoming technical challenges, achieving stable yields, and maintaining competitive costs. The collaboration between Intel and Lens Technology signals the expansion of semiconductor packaging into the fields of materials science and precision manufacturing. Future chip performance will depend not only on wafer technology but also on packaging materials and processes.