Chiplets and UCIe: why modular processors matter for embedded

In the last ten years the semiconductor industry has seen one of the greatest technological revolutions: the affirmation of model a chiplets. For a long time microprocessors were designed as monolithic blocks, where all the functions – CPU cores, cache memory, graphics accelerators, interfaces of communication – coexisted on the same silicon die. This approach has allowed great progress, but it showed increasingly stringent limits: chips became huge, expensive to produce and difficult to scale.

Today the trend is to break down the processor into smaller and more specialized modules, namely chiplets, capable of be manufactured separately and then integrated into a single package. A modular logic that not only reduces costs production, but paves the way for new, more flexible and customizable architectures.

Why chiplets are changing the paradigm

The transition is not only technological, but also strategic. In a monolithic die, production yield is a critical factor: a microscopic defect is enough to compromise the entire chip, with enormous costs. Chiplets reduce risk, because each block is smaller and independent.

Another advantage is the possibility of combining different technology nodes: the CPU can be manufactured at 5 nm for maximize performance, while analog or I/O modules can remain at 28 nm, where costs are lower and electrical stability is greater. It's a form of engineering optimization which was not practicable before.

The industry has already demonstrated the maturity of the model. AMD has made chiplets a mainstay of its Ryzen and EPYC CPUs, separating the compute cores from the I/O die. Intel took a similar approach with its Meteor Lake tile architectures. ARM and SiFive are also looking at this path with interest, especially in a RISC-V key, where modularity is almost a natural requirement.

Packaging and integration techniques

The real strength of chiplets lies not only in the logical division of functions, but also in the packaging techniques that make their integration possible. The solutions 2.5D, like the TSMC CoWoS, they use a silicon interposer that acts as a high-speed bridge between the various chiplets. The architectures 3D stacking, however, allow you to stack multiple dies vertically, reducing distances physical and increasing the density of interconnections.

Intel has developed technologies such as EMIB (Embedded Multi-die Interconnect Bridge) e Foveros, which allow you to combine chiplets made with different nodes while maintaining performance close to those of monolithic chips. For embedded, where PCB space is often limited, these approaches open up the possibility integrate advanced functions without having to completely redesign the board.

Interconnections and latency

One of the most critical points concerns communication between chiplets. In a monolithic die, signals travel minimal distances, while in a modular package it is necessary to manage longer and more complex connections. This introduces challenges latency, power consumption and signal integrity.

Emerging standards such as UCIe (Universal Chiplet Interconnect Express) they aim to guarantee interoperability and reduced latencies, with bandwidths that can reach hundreds of GB/s. For embedded this aspect is fundamental: in real-time applications, even a few nanoseconds of delay can cause the difference between a reliable system and one that does not meet specifications.

Consumption and thermal management

Thermal design in chiplet systems is radically different. In a monolithic chip the heat is concentrated in a single area, while in modular systems the hot spots can be in different positions of the package. This requires new dissipation strategies, especially in compact devices such as IoT gateways, wearables or automotive systems.

At the same time, the physical separation of the most energy-intensive modules, such as an AI accelerator, allows for better isolation heat sources and apply targeted cooling techniques. This can translate into higher overall efficiency compared to an equivalent monolithic die, as long as the thermal design is optimized from the early design stages.

Embedded: from spectator to protagonist

The question that those who work in embedded fields ask themselves is whether this approach, born in data centers and high-performance PCs, really makes sense in industrial, automotive or IoT devices. The answer is yes, but with a different trajectory.

In the embedded world the constraints are not only related to computing power: low consumption, low costs and availability count guaranteed for 10 or 15 years, reliability in extreme environmental conditions. At first glance, a multi-chiplet packaging can appear more fragile or expensive than a traditional microcontroller. However, the benefits of modularity are being realized road. For example, imagine a medical device manufacturer that wants to update its product with a AI accelerator for real-time analytics: With a chiplet architecture, it can add the AI module to the existing package without redesigning the entire system.

RISC-V and natural modularity

The architecture RISC-V represents particularly fertile ground for chiplets. Its open nature and modular goes perfectly with the possibility of implementing dedicated extensions in separate modules. There are already experimental designs that combine general-purpose RISC-V cores with accelerators for AI or DSP in configurations chiplet, paving the way for customized systems with reduced development time.

For the embedded sector, where product differentiation is often a competitive factor, the possibility of having Custom SoCs built around RISC-V cores could represent a concrete alternative to traditional microcontrollers from vendors such as ARM, NXP or STMicroelectronics.

Academic research and trends

The world of research is already moving in this direction. Universities and research centers are developing tools EDA (Electronic Design Automation) designed for modular architectures, simulators that allow you to model interconnections between chiplets and studies on new materials for low resistance interposers.

The interest is driven above all by two sectors: theAI at the edge and theIndustrial IoT. Both require systems that combine energy efficiency, security and high computing capacity in small spaces. Academic research already provides models to estimate power consumption, delays and scalability of chiplet architectures, assuming the foundations for future mass adoption also in the embedded market.

A silent revolution

Many observers see chiplets as a “luxury” solution for high-end processors. In fact, the path of these technologies follow the same curve we saw with SoCs: first introduced in premium applications, then progressively standardized and finally adopted en masse even in low-cost embedded devices.

Today it still seems like a distant concept, but it is plausible that in five or ten years there will also be mid-range microcontrollers they will integrate modular architectures, with chiplets dedicated to specific functions.

Conclusion

The chiplet revolution is not a phenomenon limited to servers and gaming PCs: it is a paradigm shift that inevitably it will also reach the embedded. Modularity opens up scenarios extreme customization, reduced development time and long-term upgradeability.

The challenge of standardization and software maturity remains to be addressed, but the direction is set. The embedded systems of the future will no longer be thought of as monolithic blocks, but rather as modular ecosystems, capable of adapting and growing together with market needs.

Useful insights:
UCIe – Universal Chiplet Interconnect Express
AMD Infinity Fabric Overview
Intel Foveros Packaging Technology
TSMC CoWoS Technology
SiFive RISC-V Strategy