A Beginner’s Guide to Chiplets: 8 Best Practices for Multi-Die Designs

• Chiplet best practices
• Unlocking the benefits of chiplet-based designs

Here are eight best practices for those considering chiplet-based approaches:

1. Start with smart system partitioning
   Begin by breaking down the system design into functional blocks — such as compute, memory, and I/O — and determine which functions should exist as separate chiplets. Select the most advanced process nodes for high-performance components, while opting for proven, cost-effective nodes for less demanding blocks. Throughout this process, carefully balance the tradeoffs between speed, power consumption, and overall system efficiency. Additionally, plan for scalability by choosing standards and interfaces that will allow for future upgrades or changes.
2. Select the best process node for each chiplet
   Not every function benefits equally from the latest technology. For example, memory may not scale as efficiently as logic, so manufacturing a memory chiplet on a less advanced node can reduce costs without compromising performance. When integrating chiplets, consider whether they should be stacked in a 3D configuration for lower latency and power or placed side-by-side in a 2.5D arrangement for ease of implementation.
3. Plan die-to-die connectivity carefully
   Choosing the right interface is crucial for seamless communication between chiplets. Industry standards like UCIe are becoming increasingly popular for die-to-die connectivity. It’s essential to match the bandwidth of the design’s connections to the system’s required data throughput, accounting for both main data and sideband control data. In addition, optimize the physical layout by carefully planning how chiplets will be placed and interconnected within the package, ensuring the design fits within the target size and shape. Depending on the physical layout, the amount of available "beachfront" for die-to-die interfaces may vary, requiring different interface configurations. Don’t forget to prioritize thermal management — multiple chiplets in a single package can create hot spots, so adequate cooling and heat dissipation must be built into the design.
4. Understand advanced packaging options
   Selecting the appropriate packaging technology is key to achieving design goals. Options range from traditional organic substrates to advanced interposers that support higher density and performance. Consider the form factor and overall cost, as advanced packaging solutions typically offer greater capabilities but can also be more expensive and complex to implement. Make sure the development timeline allows for robust testing and yield management. Each chiplet should be tested individually, ensuring only known good dies (KGDs) are selected for final assembly. Including redundancy and repair features in die-to-die interfaces can improve packaging yield during assembly, test, and in-production. Additionally, carefully monitor the supply chain to ensure reliable sourcing for all chiplet components and packaging materials.
5. Design with security in mind
   Security should be a foundational element of all chiplet-based systems. Ensure each chiplet is authenticated and anchored by a Root of Trust (RoT) to prevent unauthorized access and securely manage security keys, particularly in multitenant environments. Protect data in transit between chiplets by using encryption and secure communication protocols. Also, plan for a secure boot process to prevent tampering at both the hardware and software levels.
6. Invest in system-level design and verification
   Early and frequent system-level simulation and hardware-assisted verification can help catch integration issues before hardware is built, saving precious time and resources. Co-design hardware and software in tandem to accelerate development and improve time-to-market. It’s also critical to build robust test plans for both individual chiplets and the final packaged system to ensure reliability and performance. New methodologies, such as hierarchical testing, can help evaluate individual chiplets and verify their performance after assembly in a multi-die design. It’s also important to invest in system-level thermal modeling and crosstalk analysis to accurately assess multi-die interactions in the final product.
7. Focus on the control and management system
   Many chiplets, particularly in data center environments, can benefit from a dedicated control and management system. These systems have a CPU that manage initialization, low-speed peripherals, and security features like RoT. They can also help improve silicon reliability, availability, and serviceability (RAS) by gathering, aggregating, and disseminating telemetry data.
8. Leverage ecosystem partners and expertise
   Because chiplet technologies and approaches are still relatively new and continue to evolve, working with experienced partners is essential. Industry leaders like Synopsys provide design services and packaging guidance in addition to silicon-proven IP solutions. These IP solutions are being integrated with Arm Compute Subsystems (CSS) to further speed chiplet development and reduce risk. Staying informed about the latest chiplet standards is also crucial. Industry groups such as the UCIe Consortium and JEDEC provide valuable updates and resources on new developments in chiplet technology. And organizations like imec and ASRA are developing specialized proposals and chiplet guidelines for the automotive industry.

Chiplet-based designs offer a flexible and scalable path to building next-generation, high-performance systems. By following these best practices, design teams can navigate the complexities and fully realize the benefits of chiplet-based approaches. For guidance throughout the chiplet journey — from concept to product — consider partnering with experts who understand the entire landscape, from silicon to system integration.