The journey to implementing a 2.5D System-in-Package (SiP) with High Bandwidth Memory (HBM) is complex and multifaceted. It involves defining the architecture, designing a highly reliable interposer channel, and conducting robust testing of the data path, including system-level validation. Each step in the process is critical to achieving high performance and reliability.
Effective system architecture planning is essential, as it lays the groundwork for meeting bandwidth, latency, and power requirements. Disaggregating a monolithic chip into smaller, specialised modules, or chiplets, offers enhanced flexibility, scalability, and efficiency. This approach allows for better handling of specific functions while improving overall yield.
A significant element of HBM implementation lies in designing the interposer, which serves as a dense routing platform between the HBM stacks and the compute die. With HBM4, the challenges intensify as it builds on HBM3E by pushing data rates and energy efficiency while maintaining the same memory shoreline. The increased interface width of 2048 bits requires meticulous routing to manage denser I/O, reduce signal loss, and ensure compliance with HBM4E specifications. Alphawave Semi has taken strides in this area by creating a comprehensive in-house test vehicle to study the full signal integrity of the data path.
Signal integrity (SI) and power integrity (PI) analysis play pivotal roles in mitigating signal degradation at the advanced data rates of HBM4E. Techniques such as impedance matching, shielding, and equalisation are used to maximise the signal’s EYE opening and optimise data transmission. The interposer undergoes rigorous analysis for factors like insertion loss, crosstalk, and impedance to ensure it meets HBM4E requirements. Similarly, the power delivery network is engineered to minimise noise and maintain stability, considering contributions from all system components.
Testing and validation at the system level are critical to confirming performance against design specifications. Decomposing interposer-induced jitter into its components allows for targeted optimisations, ensuring signal clarity and reducing power inefficiencies. Alphawave Semi employs a robust suite of design-for-test (DFT) standards, enabling early diagnostics and high yield, further solidifying the reliability of its solutions.
While HBM4 systems promise significant performance gains and lower latency, they come with inherent technical challenges. From architecture and interposer design to signal and power analysis, each step demands precision and innovation. Alphawave Semi is addressing these challenges head-on, developing high-performance HBM4 solutions that are expected to drive advancements in AI and data centre technologies. The evolution of memory systems underscores the need for custom integrations, enabling computational systems to meet the demands of the data-driven world.
The push for advanced memory technologies like HBM4 reflects the growing need for innovative solutions in the data revolution. By overcoming the complexities of implementation, Alphawave Semi positions itself as a leader in delivering cutting-edge, reliable memory systems that stand as a cornerstone for future computing advancements.
Alphawave IP Group plc (LON:AWE) is a semiconductor IP company focused on providing DSP based, multi-standard connectivity Silicon IP solutions targeting both data processing in the Datacenter and data generation by IoT end devices.
