AT&S Advances Glass Core Substrates for AI, HPC, and Photonics

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AT&S is advancing glass core substrates from research toward industrial use in artificial intelligence, high-performance computing, high-speed communications and photonics. As chips for AI data centers and advanced networks become larger and more complex, conventional substrate materials reach their limits in dimensional stability, signal quality, and energy efficiency. Glass offers a promising alternative: it stays flat, reduces electrical loss and supports highly precise structures, making it well suited for the next generation of advanced microchip packages.

In practical terms, a glass core substrate is the stable inner layer of a chip package. It features fine copper structures that distribute power and transmit data between processor, memory, and the wider system. Because glass is exceptionally planar and electrically stable, it can support smaller structures, cleaner signal transmission, and larger package formats than conventional organic materials. Applications such as AI accelerators and high-bandwidth data centers benefit from more performance, minimal space requirements, lower losses, and better thermal behavior.

Built for next-generation computing

AT&S has been working on glass substrate technology for several years and is in the process of developing the capabilities to bring it to industrial use. This includes through-glass vias for vertical electrical connections, advanced copper patterning, and panel-based manufacturing approaches for future high-volume production. The company’s competence center for R&D and IC Substrate production in Leoben, supported through the European Union’s IPCEI ME/CT framework, plays a central role in this effort and links research and industrialization.

“Glass core substrates are helping shape the systems that will power the AI era. They provide a stable foundation for larger, more capable chip packages and create opportunities for new functionalities, including optical links inside the package itself. At AT&S, progress is always the result of close collaboration across research, engineering, manufacturing, supply chain management and our partner network. Together, we transform a promising idea into a reliable product,” says AT&S CTO Peter Griehsnig.

Clear path to industrial deployment

One of the most important opportunities for glass core substrates lies in co-packaged optics: the integration of optical connections alongside electrical structures directly in the package. Because glass combines dimensional stability with optical transparency, it is a strong candidate for future systems that need to move very large volumes of data with minimal latency and low power consumption. That is particularly relevant for AI infrastructure, where performance gains increasingly depend not only on raw compute, but also on how efficiently data can move through the system.

Glass supports larger multi-die packages for GPUs, CPUs, and memory-rich systems and aligns with the semiconductor industry’s move toward panel-level manufacturing. AT&S is addressing the challenges of large-scale deployment, including handling thinner glass safely, ensuring reliability under thermal stress, and preparing manufacturing and inspection systems for volume production. With the competence center in Leoben and additional manufacturing and research hubs in Europe and Asia, AT&S is well positioned to help customers design, prototype, and scale glass-based systems for the next generation of AI and high-performance computing.