Chiplet Actuary: A Quantitative Cost Model and Multi-Chiplet Architecture Exploration

Core Concepts

Multi-chip integration can provide cost benefits through yield improvement, chiplet and package reuse, and heterogeneity, but the advantages depend on various factors and require careful evaluation.

Abstract

The paper presents the Chiplet Actuary model, a quantitative cost model for comparing the recurring engineering (RE) and non-recurring engineering (NRE) costs between monolithic system-on-chip (SoC) and multi-chip integration.
The key insights are:

Multi-chip architecture begins to pay off when the cost of die defects exceeds the total cost resulting from packaging. The closer to the Moore Limit (the largest area at the most advanced technology) the system is, the higher the cost-benefit from multi-chip architecture.
For a single system, monolithic SoC is a better choice unless the production quantity is large enough to amortize the NRE overhead of multiple chiplets.
Whether to reuse packaging depends on whether the RE or the amortized NRE cost is dominant.
The paper explores three chiplet reuse schemes (SCMS, OCME, FSMC) and shows how they can achieve cost benefits through different approaches.
Despite the benefits, advanced packaging technologies like InFO and 2.5D still suffer from poor yield and area limits, limiting the fundamental extension of Moore's Law.

Stats

The cost of raw chips accounts for a significant portion of the total recurring engineering (RE) cost, especially for advanced process technologies.
The cost of packaging, including the cost of raw packages, package defects, and wasted known good dies, can be a major contributor to the total RE cost, especially for advanced packaging technologies.

Quotes

"Multi-chip architecture begins to pay off when the cost of die defects exceeds the total cost resulting from packaging."
"For a single system, monolithic SoC is a better choice unless the production quantity is large enough to amortize the NRE overhead of multiple chiplets."
"The basic principle is building more systems by fewer chiplets, and the cost benefits of chiplet reuse are more evident for finely segmented demands."

Key Insights Distilled From

Chiplet Actuary

by Yinxiao Feng... at arxiv.org 04-10-2024

https://arxiv.org/pdf/2203.12268.pdf

Deeper Inquiries

How can the Chiplet Actuary model be extended to incorporate performance, power, and other non-cost factors in the decision-making process for multi-chip architectures

To extend the Chiplet Actuary model to incorporate performance, power, and other non-cost factors in the decision-making process for multi-chip architectures, several adjustments and additions can be made. Firstly, performance metrics such as throughput, latency, and bandwidth can be integrated into the model to evaluate the impact of different chiplet configurations on system performance. Power consumption analysis can also be included to assess the energy efficiency of the architecture.
Incorporating these factors would require developing performance and power models for each chiplet and the overall system. Performance models could consider factors like inter-chiplet communication latency, data transfer rates, and processing capabilities. Power models would need to account for the power consumption of individual chiplets, interconnects, and the overall system.
Furthermore, non-cost factors such as reliability, scalability, and thermal management should be considered. Reliability models can predict the failure rates of chiplets and their impact on system operation. Scalability analysis can determine how well the architecture can adapt to changing requirements. Thermal management models can assess the heat dissipation capabilities of the system.
By integrating these performance, power, and non-cost factors into the Chiplet Actuary model, designers can make more informed decisions about multi-chip architectures based on a comprehensive evaluation of various aspects beyond just cost.

What are the potential challenges and limitations of the chiplet reuse schemes (SCMS, OCME, FSMC) in real-world scenarios, and how can they be addressed

The potential challenges and limitations of chiplet reuse schemes like SCMS, OCME, and FSMC in real-world scenarios stem from several factors. One challenge is the complexity of managing multiple chiplets with different functionalities, interfaces, and technologies. Coordinating the design, testing, and integration of diverse chiplets can be challenging and may lead to compatibility issues.
Another limitation is the scalability of chiplet reuse schemes. As the number of chiplets and systems increases, the complexity of managing interactions, dependencies, and optimizations also grows. This can result in diminishing returns in terms of cost savings and efficiency.
Addressing these challenges requires robust design methodologies, standardized interfaces, and efficient communication protocols. Design automation tools can help streamline the integration process and ensure compatibility between chiplets. Additionally, establishing clear guidelines for chiplet selection, verification, and validation can mitigate risks associated with chiplet reuse.
Furthermore, in real-world scenarios, ensuring adequate testing and validation of chiplets and systems is crucial to identify and resolve any issues early in the design process. Continuous monitoring and optimization of the chiplet reuse schemes are essential to adapt to changing requirements and technologies.

Given the limitations of advanced packaging technologies, what alternative approaches or innovations could be explored to further extend the benefits of multi-chip integration beyond the current constraints

Given the limitations of advanced packaging technologies such as InFO and 2.5D, alternative approaches and innovations can be explored to further extend the benefits of multi-chip integration. One approach is to investigate novel packaging techniques like chip stacking, 3D integration, or wafer-level packaging. These methods can offer higher interconnect density, improved signal integrity, and better thermal management compared to traditional packaging technologies.
Moreover, exploring advanced interconnect technologies such as silicon photonics, optical interconnects, or on-chip networks can enhance the communication efficiency between chiplets. By leveraging these technologies, the bandwidth, latency, and power efficiency of inter-chiplet communication can be significantly improved.
Additionally, focusing on system-level optimization through architectural innovations like domain-specific accelerators, heterogeneous computing, and reconfigurable architectures can maximize the benefits of multi-chip integration. By tailoring the system architecture to specific workloads and applications, designers can achieve higher performance, energy efficiency, and scalability.
Furthermore, investing in research and development of new materials, manufacturing processes, and design methodologies can lead to breakthroughs in multi-chip integration. Collaborations with industry partners, academia, and research institutions can drive innovation in chiplet technologies and pave the way for the next generation of high-performance computing systems.