For those who came in late, glass substrates, made from materials like borosilicate, quartz, and fused silica, offer notable benefits over traditional organic materials. They feature exceptional flatness, dimensional stability, and superior thermal and mechanical stability.
Superior flatness and dimensional stability can improve lithography focus for ultra-dense interconnects in advanced system-in-packages, while superior thermal and mechanical stability makes them more reliable for high-temperature, heavy-duty applications like data centre processors.
According to Tom’s Hardware glass substrates are set to replace traditional organic substrates for multi-chiplet processors in the coming years.
The patent ensures the company can use glass substrates in the future without the risk of being sued by patent trolls or competitors.
Most chipmakers, including Intel and Samsung, are exploring glass substrates for future processors. Although AMD no longer produces its own chips, instead subcontracting them out to TSMC, it still maintains silicon and chip production research and development operations, customising process technologies offered by its partners to build its products.
One of the challenges when working with glass substrates is the implementation of Through Glass Vias (TGVs), according to the AMD patent. TGVs are vertical pathways created within the glass core to transmit data signals and power. Techniques such as laser drilling, wet etching, and magnetic self-assembly are used to produce these vias, but for now, laser drilling and magnetic self-assembly are novel technologies.
Redistribution layers, which route signals and power between the chip and external components using high-density interconnections, are another integral component of advanced chip packages.
Unlike main glass core substrates, these will continue to use organic dielectric materials and copper; only this time, they will be constructed on one side of the glass wafer, requiring a new production method.
The patent describes a method for bonding multiple glass substrates using copper-based bonding (instead of traditional solder bumps) to ensure strong, gap-free connections. This approach enhances reliability and eliminates the need for underfill materials, making it suitable for stacking multiple substrates.
AMD's patents state that glass substrates offer benefits such as better thermal management, mechanical strength, and improved signal routing capabilities, which are advantages for data centre processors.
The patent implies that glass substrates could be applied to a variety of applications requiring high-density interconnections, including data centres, mobile devices, computing systems, and advanced sensors.
