Why subfab systems are becoming critical in the AI-driven advanced packaging era

As AI drives advanced packaging towards greater complexity and scale, vacuum, exhaust and abatement systems are becoming critical to improving semiconductor manufacturing throughput, yield and sustainability.

BY Rachel Ren, Edwards Vacuum

The semiconductor industry is undergoing a fundamental transition. For decades, performance improvements were largely achieved through transistor scaling, guided by Moore’s Law. Today, that paradigm is no longer sufficient to meet the demands of emerging applications, most notably artificial intelligence (AI).

AI workloads, particularly those associated with large language models and generative systems, are driving unprecedented increases in compute density, memory bandwidth, and system complexity. As a result, the semiconductor market is accelerating toward the trillion-dollar threshold faster than previously anticipated, reflecting not only cyclical recovery but structural transformation.

However, the most significant shift is not simply in demand, but in how performance is delivered. The industry is moving from device-centric scaling to system-level optimization, where integration, interconnect, and infrastructure increasingly define performance limits.

Within this context, advanced packaging has emerged as a critical enabler of AI systems. Yet beneath this visible transformation lies a less discussed but equally important constraint: subfab infrastructure. Vacuum, exhaust, and abatement systems, historically treated as support utilities, are rapidly becoming essential to enabling throughput, yield, and sustainability in advanced manufacturing.

AI and the shift to system-level scaling
AI workloads impose a unique set of requirements on semiconductor systems. Unlike traditional computing applications, they demand simultaneous scaling across multiple dimensions: compute throughput, memory capacity, interconnect bandwidth, and power efficiency. These requirements have exposed the limitations of relying solely on transistor scaling to drive performance.

As a result, the industry has converged on a system-level architecture that integrates advanced logic, high-bandwidth memory (HBM), and advanced packaging technologies such as 2.5D interposers, 3D stacking, and chiplet-based designs.

This approach enables performance gains by optimizing data movement and system integration rather than relying exclusively on device shrink.

Advanced packaging has therefore transitioned from a back-end process to a primary driver of system performance. Heterogeneous integration allows designers to combine logic, memory, and specialized accelerators in close proximity, reducing latency and increasing bandwidth. Industry analysts have highlighted that technologies such as hybrid bonding and wafer-level integration are essential to sustaining performance growth in high-volume manufacturing.

This shift also reflects a broader change in scaling philosophy. Performance is no longer defined by the smallest feature size, but by the efficiency with which components are integrated into a complete system.

Advanced packaging as the “Middle-End”
The evolution of advanced packaging is redefining the traditional boundaries of semiconductor manufacturing. Historically, the industry was divided into front-end processes for transistor fabrication and back-end processes for assembly and packaging. Today, advanced packaging occupies an intermediate domain often described as the “middle-end.”

This middle-end combines elements of both FE and BE. Processes such as through-silicon vias (TSV), redistribution layers (RDL), and hybrid bonding rely on FEOL-class techniques, including etch, chemical vapor deposition (CVD), and atomic layer deposition (ALD). At the same time, these processes are closely tied to system-level integration and final device assembly.

The result is a convergence of process complexity and integration requirements. Advanced packaging is no longer a passive assembly step; it is a yield-critical, performance-defining stage of manufacturing. Increasingly, these processes are being integrated directly into leading-edge wafer fabs, further blurring the distinction between front-end and back-end operations.

The emerging constraint: Subfab infrastructure
While attention has focused on device architectures and packaging technologies, the supporting infrastructure within the subfab is becoming a critical determinant of manufacturing performance. Subfab systems are responsible for maintaining vacuum conditions, managing process exhaust, and ensuring safe and efficient handling of process byproducts. These functions are essential for enabling the advanced processes required in both FEOL and advanced packaging environments.

In modern high-volume manufacturing, subfab environments are highly complex systems. A single fab may contain thousands of vacuum pumps and abatement units. Typically, each process chamber is supported by a dedicated dry vacuum pump, while each multi-chamber process tool shares a common abatement system that treats exhaust from all of its chambers. Failures or inefficiencies in these systems can have immediate and significant impacts on throughput and yield.

As process complexity increases, the role of subfab infrastructure is shifting from passive support to active performance enabler. This shift is driven by several converging challenges.

Advanced packaging processes are characterized by higher material volumes and more complex process flows than traditional back-end operations. Steps such as TSV etch and dielectric deposition require higher gas flow rates, tighter pressure control, and more stringent process stability.

These requirements place new demands on vacuum systems. Pumping speed and stability directly influence process cycle time and uniformity. Faster pump-down times enable higher throughput, while stable vacuum conditions reduce process variation and defect formation. In high-volume manufacturing, even small improvements in these parameters can translate into significant gains in productivity and cost efficiency.

The relationship between vacuum performance and manufacturing output is therefore becoming increasingly direct. Subfab systems are no longer peripheral to productivity; they are integral to it.

Materials innovation and chemical complexity
The introduction of new materials and processes has significantly increased the chemical complexity of semiconductor manufacturing. Advanced packaging and leading-edge FEOL processes involve a wide range of reactive gases, condensable byproducts, and corrosive chemistries.

These conditions present substantial challenges for vacuum and exhaust systems. Condensation of byproducts within pumps or exhaust lines can lead to blockages, increased power consumption, and eventually system failure. At the same time, efforts to prevent condensation, such as increasing operating temperature, can accelerate corrosion and material decomposition.

Balancing these competing effects requires a detailed understanding of process chemistry and careful design of thermal and material systems. Failure to manage these interactions can result in reduced equipment lifetime, increased maintenance requirements, and unplanned downtime.

Thermal management beyond the process chamber
Thermal control has traditionally been focused on the process chamber, where temperature directly affects film deposition and etch performance. However, as process complexity increases, thermal management must extend throughout the entire gas handling pathway, including forelines, pumps, and exhaust systems.

Chemical reactions do not cease at the chamber boundary. Byproducts can continue to react or condense within the vacuum system, influenced by local temperature and pressure conditions. Maintaining an appropriate thermal profile across this extended system is critical to prevent both condensation and decomposition.

This creates a narrow operating window. Temperatures that are too low promote condensation and particle formation, while temperatures that are too high can lead to unwanted chemical reactions and material degradation. Achieving the correct balance is essential for maintaining process stability and yield.

Footprint constraints and equipment density
Another significant challenge arises from the increasing density of process tools within advanced fabs. To maximize productivity and return on capital investment, manufacturers are deploying multi-chamber cluster tools with up to ten or more process modules per platform.

While tool density increases, available subfab space does not. Supporting systems must fit within the footprint of the process tool, often referred to as the tool “shadow.” As a result, vacuum and abatement systems must deliver higher performance within increasingly constrained physical dimensions.

Industry trends indicate a need for substantial reductions in equipment footprint, on the order of 20–30%, while simultaneously increasing capacity.

This creates a fundamental engineering challenge: delivering higher pumping speed and flow capacity without increasing system size. Solutions require innovations in system design, modularization, and integration.

Energy consumption
Energy efficiency has become a central concern in semiconductor manufacturing, driven by both economic and environmental factors. Subfab systems are among the largest consumers of energy within a fab. Estimates suggest that vacuum and abatement systems can account for approximately 20% of total facility energy consumption, and in some process tools, vacuum alone represents more than half of total power usage.

At the same time, the industry is under increasing pressure to reduce greenhouse gas emissions and meet sustainability targets. Analysis of vacuum system lifecycle emissions indicates that the vast majority, approximately 97%, are associated with energy consumption during operation.

This makes energy efficiency a key lever for both cost reduction and environmental impact. Improvements in pump design, system integration, and operational control can significantly reduce energy usage while maintaining or improving performance.

Digitalization and predictive maintenance
The increasing complexity of subfab systems has driven the adoption of digital technologies and data-driven approaches. Modern fabs generate large volumes of data from sensors monitoring pressure, temperature, vibration, and flow. When combined with advanced analytics and domain knowledge, this data can be used to predict equipment failures and optimize system performance.

Predictive maintenance represents a significant advancement over traditional preventive approaches. By identifying early indicators of degradation, maintenance can be scheduled proactively, reducing unplanned downtime and extending equipment life.

Moreover, integrating data across the entire vacuum and abatement system enables a holistic understanding of system behavior. Interdependencies between components can be identified and addressed, improving overall reliability and performance.

Sustainability as a system-level constraint
Sustainability is rapidly emerging as a defining constraint in semiconductor manufacturing. TSMC recently committed to achieving net-zero emissions by 2050, reflecting a broader industry recognition that environmental impact must be addressed alongside performance and cost.

While the semiconductor sector is not a major direct emitter of greenhouse gases, its indirect footprint driven by energy-intensive manufacturing and the rapid growth of AI infrastructure is significant and expanding. The industry increasingly applies the Greenhouse Gas Protocol framework, which categorizes emissions into Scope 1 (direct), Scope 2 (purchased energy), and Scope 3 (value chain), to guide sustainability strategies across operations and supply chains.

Subfab systems play a central role in this effort. Vacuum and abatement infrastructure directly influence all three emission scopes: they consume substantial power, manage process exhausts, and impact downstream efficiency. As a result, sustainability in the subfab is no longer a compliance issue but a system-level engineering challenge.

Advances in abatement and energy-efficient vacuum technologies are already delivering measurable impact. In 2020, Edwards’ abatement systems prevented approximately 17.7 million tons of CO₂-equivalent emissions at customer facilities comparable to the annual emissions of cities such as Madrid and Milan. These results illustrate the scale at which subfab innovation can contribute to industry-wide decarbonization.

Looking ahead, achieving sustainability targets will require tighter integration between process tools and subfab systems, real-time energy optimization, and continued collaboration across the supply chain. Subfab infrastructure is therefore becoming a critical lever, not only for manufacturing performance, but for enabling sustainable scaling in the AI era.

From support function to strategic lever
The cumulative impact of these trends is a fundamental redefinition of the role of subfab infrastructure. No longer confined to a supporting role, subfab systems now directly influence key manufacturing outcomes, including yield, throughput, reliability, and cost of ownership.

This shift reflects a broader transition within the semiconductor industry toward system-level optimization. As processes become more complex and interconnected, performance depends on the coordinated operation of all system components. Subfab infrastructure is an integral part of this system.

Conclusion
The semiconductor industry is entering an era where scaling is no longer defined solely by device dimensions. Instead, it is increasingly determined by the ability to integrate and manufacture complex systems at scale.

Advanced packaging has emerged as a critical enabler of this transition, providing the means to overcome the limitations of traditional scaling. However, the effectiveness of these technologies depends on the performance of the underlying infrastructure.

Subfab systems, vacuum, exhaust, and abatement, are now central to achieving the throughput, yield, and sustainability required for next-generation manufacturing. They are no longer invisible utilities but strategic assets that directly influence competitive performance.

In the AI-driven era, the winners will not only be those who design the most advanced chips, but those who can manufacture them efficiently, reliably, and sustainably. Achieving this will require a holistic approach that integrates device innovation, process development, and infrastructure engineering.

Ultimately, the path forward is clear: scaling is no longer just about the chip, it is about the infrastructure that enables it.