1. HDI Technology Upgrade: In NVIDIA’s AI servers, to meet the demand for massive data transmission, the number of PCB layers has increased from the traditional 8 layers to 20 – 30 layers, and the materials have been replaced with high-speed, low-loss specialty substrates. The upgrade of the 1.6T switch has driven the upgrade of PCB materials and the development of high-layer count PCBs, significantly increasing their value, with growth during the prototyping phase reaching over 50%.
2. Reasons for High PCB Usage by ASIC Manufacturers: ASIC manufacturers use higher layer counts and higher-grade materials to compensate for the high power consumption and losses of their chips.
3. Specific PCB Requirements for OAM/UBB: OAM boards interconnect with core chips like GPUs and have high requirements for HDI technology. NVIDIA’s latest products use HDI with more than 5 layers and may evolve to 7 layers; AMD’s products typically use around 3 layers of HDI; ASIC manufacturers generally use 2 to 3 layers of HDI. For example, the PCB of NVIDIA’s GB200 server uses a 6-layer 24-layer HDI process, with a usage amount 5 times that of traditional servers; UBB is mainly used to connect OAM boards with other components, does not directly carry chips, and usually does not require HDI technology, often using through-hole designs, primarily responsible for high-speed signal transmission. Its layer count is generally above 16 layers, and to ensure low-loss signal transmission, high-performance resin materials such as PPO need to be selected.
4. Cooperation Status of Domestic Manufacturers: Amazon mainly collaborates with Shengyi Electronics, Google tends to work with Shenzhen Circuits, and companies like Guanghe are involved in the production of some small boards.
5. Differences in HDI Value Among Different Manufacturers: The five-layer HDI on NVIDIA’s OAM is approximately 700 – 800 yuan per square meter, while the two to three-layer HDI used by Amazon and Google is about 200 yuan per square meter, with a potential shift towards higher-layer HDI in the future.
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