From Always-On to Intelligent
How INFICON is closing the subfab energy gap.
Semiconductor fabs have made significant efficiency gains on the process side over the past decade. The subfab has not kept up.
Vacuum pumps, abatement systems, foreline heaters, and purge gas delivery collectively account for roughly 40% of total fab energy consumption, yet they default to always-on operation, running continuously regardless of whether the process tool above them is doing anything at all. This is not an oversight. It is a safety design choice that made sense when subfab systems had no visibility into tool state, no connection to factory scheduling, and no safe mechanism to do anything different. The result is billions of kilowatt-hours consumed globally each year that produce no wafers.
With the semiconductor industry committing to SEMI SCC targets of 43% Scope 1 emissions reduction from 2019 levels by 2030, that gap can no longer be accepted as the cost of doing business.
Two Types of Control, One Integrated Architecture
INFICON has developed and deployed a production-grade subfab control architecture that addresses this problem at scale. The approach classifies subfab actuators into two tiers based on their physical transition characteristics, then applies the right control logic to each.
Type I systems respond quickly. Abatement burn control, nitrogen purge flows, and pump eco modes can safely transition within seconds when a process tool goes idle. INFICON drives these transitions in real time using process tool state acquired via SECS/GEM and Interface A, delivering multi-level eco mode signals through dry contact I/O or serial and TCP ports depending on equipment capability. Zero wafer risk. Fast payback.
Type II systems require more planning. Foreline heaters and chillers carry significant thermal mass. Transition them too early and you recover energy you immediately spend reheating. Transition them too late and you miss the window entirely, or worse, create a process excursion when the tool comes back online before the foreline reaches temperature. For Type II, WIP scheduling lookahead is not optional, it is the entire point. INFICON integrates directly with factory WIP scheduling to calculate transition timing precisely, capturing substantially larger savings than equipment-level control alone can deliver.
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The Technical Barriers Were Real
Building a production-ready version of this architecture required solving problems that are easy to underestimate from a whiteboard.
Legacy subfab equipment does not communicate on a standard protocol. The reality across most tool fleets is a mix of RS-485 Modbus, hardwired relay I/O, and proprietary OEM protocols. INFICON addressed this with a purpose-built IO integration architecture that combines communication protocol support and relay modules with dry contact I/O, presenting a unified control interface to FabGuard or third-party FDC systems without requiring OEM firmware changes. This matters because it means deployment does not depend on OEM cooperation or extended qualification cycles.
Safety continuity required a hardware-gated solution. INFICON's S2-certified fail-to-safe relay enforces nine defined failsafe conditions with reaction times measured in seconds, ensuring that eco mode transitions are hardware-gated regardless of software state. For processes involving pyrophoric or condensing gases, this is not optional, it is the certification requirement.
Mismatch detection turned out to be one of the hardest production deployment problems. When the commanded state of a relay and the actual state of a piece of equipment diverge, the consequences range from wasted energy to process risk. INFICON implemented automated Current State vs. Command State comparison with built-in alarming, developed in direct response to requirements gathered during advanced-node foundry qualification. Manual analysis of these mismatches, which was the prior approach, does not scale.
What Deployment at Scale Looks Like
This architecture is not a pilot. It is running in production across 5,000+ vacuum pumps, 750+ abatement systems, and 300+ heat trace installations at multiple IDMs and leading-edge logic fabs.
A representative abatement control case study demonstrated 58% reductions in natural gas consumption along with corresponding reductions in CO2, NOx, and CO emissions. Zero process impact. These results were validated and presented at SESHA 2024.
When WIP-integrated Type II control is added to the picture, the savings compound. A scheduler-identified idle window enables simultaneous, coordinated shutdown of the process pump, foreline heat trace, and nitrogen heater across a tool, recovering electricity consumption per idle event across large tool fleets. That compounding effect is precisely what isolated equipment-level optimization misses.
The Roadmap
The control infrastructure and safety architecture now in place create the foundation for the next step: AI-driven optimization. Target KPIs include energy per wafer, chemical usage per run, and emissions per process class. Predictive models can anticipate utility demand peaks and idle inefficiencies before they occur, rather than reacting to them. The path from condition-based to predictive to autonomous subfab operation is a direct extension of what is already running in production today.
The SEMI SCC 2030 targets are achievable. The subfab is where the gap is. Closing it requires the kind of integrated, production-validated architecture that INFICON has built and deployed, not a standalone device at the equipment level.