Thermonat Makes Nanoscale Thermal Prediction Practical for Chip Design

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As microelectronics push far below the 10-nanometer scale, heat has become one of the most significant barriers to next-generation chip performance. Packing billions, or even trillions, of transistors into fingernail-sized chips concentrates heat in ever-smaller structures, where it becomes trapped and degrades performance, accelerates defects, and can ultimately cause device failure.

Chipmakers need tools that can predict these thermally driven failures before investing years and hundreds of millions of dollars in fabrication. But existing commercial modeling tools have not been able to fully capture nanoscale heat flow, while emerging atomistic methods may be accurate but often require weeks or months to run, making them impractical for real-world design cycles.

DARPA’s Microsystems Technology Office launched the Thermal Modeling of Nanoscale Transistors (Thermonat) effort to close this gap. Thermonat aimed to combine the accuracy of atom-level physics with the speed required for industry design timelines, targeting predictions within 1°C of ground truth and reducing computation time by more than 1,000x.

“The Thermonat teams pushed the boundaries of what is possible in chip-scale thermal prediction,” said Dr. Yogendra Joshi, Thermonat’s program manager at DARPA. “By connecting fundamental physics with design-ready tools, they created capabilities that can accelerate innovation for both national-security applications and the broader semiconductor industry.”

The Thermonat performers didn’t stop once they delivered on these ambitious technical goals; they’ve built on their successes and to pursue a range of commercial pathways for their wpork.

Where Physics Meets the Marketplace

One research team, led by the University of Colorado Boulder, formed a startup, AtomTCAD Inc., to bring its high-accuracy thermal modeling tools directly to semiconductor designers. The newly formed company has received funding from the Colorado Office of Economic Development & International Trade, and all four members of AtomTCAD’s research team received fellowships through the University of Colorado Boulder’s Ascent Deep Tech Accelerator.

IBM, another Thermonat performer, has already integrated key elements of its atoms-to-circuits modeling approach into internal product design kit (PDK) processes. With this adoption, IBM has seen that designers can evaluate technology options earlier in development and generate thermally informed layouts more quickly than they could previously.

And DeepSim, a startup working with Stanford University under Thermonat, has gained early commercial traction. The company was selected for Y Combinator, a highly-sought after accelerator program, raised seed funding, and is in active discussions with several semiconductor companies to commercialize its DARPA-enabled modeling capabilities.

Rapid Exploration, Lasting Impact

Thermonat was launched under MTO’s Microsystems Exploration (µE) initiative, a rapid-start mechanism that allows DARPA to quickly probe emerging research directions through short-duration, high-risk, high-reward explorations. Thermonat exemplified this approach by delivering foundational advances in modeling, predicting, and verifying heat flow in advanced semiconductor devices – all in under 18 months – while also positioning new commercial entrants to advance national-security needs and bolster U.S. technological competitiveness.