Chiplets Wiki

Chiplets are small, functional integrated circuit (IC) blocks that are designed to work together in a modular fashion to form a complete system-on-chip (SoC) or system-in-package (SiP). Instead of building a large, monolithic chip on a single die, chiplet-based design breaks the system into multiple smaller dies that are connected using advanced packaging and interconnect technologies.

This modular approach enhances design flexibility, yields, scalability, and cost efficiency—especially as traditional silicon scaling (Moore’s Law) becomes increasingly complex and expensive.

Overview

Concept: A chiplet is a pre-fabricated silicon die that performs a specific function—such as a CPU core, GPU tile, memory controller, I/O interface, or AI accelerator.
Integration: Multiple chiplets are assembled on an interposer or substrate and connected using high-speed interconnects such as UCIe, EMIB, CoWoS, or Foveros.
Goal: To reduce the cost and complexity of advanced nodes by enabling heterogeneous integration and mix-and-match architectures.

Background and Motivation

Challenges of Monolithic Chips

Cost: Larger dies have exponentially lower yields and higher fabrication costs.
Design Complexity: Scaling to advanced process nodes (e.g., 3nm, 2nm) increases development time and risk.
Feature Integration: Mixing analog, digital, RF, memory, and specialized compute on one die is inefficient.

Chiplet Advantages

Yield Improvement: Smaller dies reduce defect-related losses.
IP Reuse: Proven chiplets can be reused across multiple products and platforms.
Node Optimization: Designers can use different process nodes for different chiplets (e.g., logic at 3nm, I/O at 28nm).
Customization: Easier to configure different product variants from a common chiplet library.

Technology and Interconnect Standards

Several interconnect technologies enable chiplet communication:

UCIe (Universal Chiplet Interconnect Express): Industry-standard open die-to-die interconnect promoted by Intel, AMD, TSMC, ASE, and others.
AMD Infinity Fabric: Proprietary high-bandwidth interconnect used across AMD chiplets.
Intel EMIB (Embedded Multi-Die Interconnect Bridge): Allows side-by-side die placement with high-speed links.
TSMC CoWoS (Chip-on-Wafer-on-Substrate): Advanced 2.5D packaging for high-bandwidth connections.
Intel Foveros: 3D stacking technology for vertical chiplet integration.

Applications

Chiplets are widely used across many semiconductor domains:

High-Performance CPUs and GPUs: AMD’s Ryzen and EPYC processors use chiplets for CPU cores, cache, and I/O.
AI and ML accelerators: NVIDIA, Intel, and startups use chiplets for scalability and memory integration.
Networking: Chiplets integrate high-speed transceivers, DSPs, and control logic.
Heterogeneous Computing: Enables mixing CPUs, GPUs, FPGAs, and custom logic in a single package.
Defense and Aerospace: Facilitates modular upgrades and radiation-hardened designs.

Industry Adoption

Major Companies Using Chiplets

AMD: A pioneer in chiplet-based x86 processors.
Intel: Uses EMIB and Foveros in Xeon, Lakefield, and future designs.
TSMC: Provides CoWoS, InFO, and UCIe-based packaging for customers.
Apple: M-series chips may evolve toward chiplet-style architectures for scalability.
NVIDIA: Leverages advanced packaging in HPC and AI applications.
Tenstorrent, Cerebras, and Esperanto: AI startups using chiplets to scale compute efficiently.

Standards and Ecosystem

UCIe Consortium

Founded in 2022, the Universal Chiplet Interconnect Express (UCIe) Consortium includes major industry players aiming to standardize die-to-die connectivity to enable a broader chiplet ecosystem.

UCIe defines:

Electrical signaling
Protocol stacks
Die-to-die PHY and link layer
System software integration

The vision is to create an open ecosystem where chiplets from different vendors can interoperate like components in a PCB system.

Challenges and Considerations

While chiplets offer many advantages, they also introduce challenges:

Design Complexity: Requires advanced packaging co-design, thermal modeling, and simulation.
Interoperability: Standardization is essential for multi-vendor integration.
Yield Coupling: While small chiplets improve yield, the package is only functional if all dies work.
Thermal Management: Denser packages need effective cooling strategies.
Software and System Integration: Ensuring seamless OS, driver, and application support for multi-die systems.

Future Outlook

Chiplets are seen as a foundational element for the post-Moore’s Law era. As scaling slows, architects are increasingly turning to system-level innovation, where chiplet-based SoCs provide:

Better performance per watt
Faster time to market
More flexible customization

The future may see an open marketplace of chiplets, where SoC designers can mix and match IPs from different vendors, much like assembling LEGO blocks, enabling faster and cheaper innovation across industries.

https://semiwiki.com/category/chiplet/

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