CoolSem Technologies, an Eindhoven-based semiconductor thermal management startup, said it has closed a pre-seed financing round led by High-Tech Gründerfonds (HTGF), with participation from KBC Focus Fund NV, the Brabant Development Agency (BOM), and TTT Green Tech B.V. (managed by SHIFT Invest). The company did not disclose the amount raised, but said the four-investor European syndicate provides a “solid runway” to move its technology from early concept toward customer-validated engineering samples.
The company is developing wafer-level thermal management technology branded as WaLTIS®, which it says is designed to reduce thermal resistance and mechanical stress in advanced semiconductor and photonic devices. CoolSem said the new capital will be used to advance WaLTIS from concept to engineering samples and to support qualification activities with top-tier customers across RF, power, and photonics, as well as to collect real-world performance evidence intended to accelerate adoption.
Thermal performance is increasingly a gating factor for modern chips as device complexity and power density rise. CoolSem is positioning its approach as a way to make chips more energy-efficient and longer-lived while supporting circular-economy goals through reduced waste and the potential reuse of scarce materials. The company says its WaLTIS multilayer stack replaces conventional substrates with an engineered stack intended to improve heat flow, enhance mechanical stability, and increase reliability for next-generation devices.
Founded in 2025 and based in Eindhoven, CoolSem sits at the intersection of semiconductor packaging, materials engineering, and thermal design, areas that have become increasingly strategic as performance gains depend on managing heat as much as improving compute. The investor group highlighted compatibility with existing semiconductor and photonics value chains, as well as the potential for the technology to become a standard element in future chip thermal design.
CoolSem’s leadership team includes CEO and CTO André van Geelen, COO Kees Steenbergen, CCO Pieter Heersink, and CSO Robbert van der Waal.
KEY QUOTES
“Heat is becoming a fundamental limiting factor in semiconductor performance. In RF, photonics, and power, conventional materials and packaging are approaching their physical limits. The pre-seed round enables us to demonstrate our wafer-level technology with early customers and advance towards industry adoption. With HTGF leading the investment and strong partners alongside, we can focus on the next phase of execution.”
André van Geelen, CEO & CTO, CoolSem Technologies
“When I first got in touch with CoolSem Technologies I was immediately intrigued by the simplicity and elegance of the approach driven by an outstanding team. I believe the technology has the potential to become an indispensable ingredient to the future thermal design of chips, an area that is more critical to the performance of semiconductor devices than ever before!”
Olaf Joeressen, Senior Investment Manager, HTGF
“We were attracted to CoolSem Technologies’ proposition because of its pragmatic and highly compatible approach. The technology integrates seamlessly into existing semiconductor and photonics value chains, enabling rapid experimentation and adoption with minor redesigns at lower cost. Their solution is turning thermal management from a limiting constraint into a scalable design advantage.”
Rudi Severijns, Investment Director, KBC Focus Fund
“We are proud to participate in this pre-seed round backed by an international consortium to enable CoolSem Technologies to validate their unique technology further. CoolSem Technologies is offering a solution to tackle thermal bottlenecks in the semiconductor industry that has the potential to unlock new and more powerful electronic chips having higher system performance, better energy efficiency and extended device lifespans. The team builds on the profound knowledge and expertise in semiconductor chip development concentrated between the regions of Eindhoven, Leuven and Aachen.”
Ivana Sersic, Senior Investment Manager, Brabant Development Agency (BOM)
“With its strong impact potential and highly capable and driven team, CoolSem Technologies is well positioned for the road ahead, and we are excited to support them on this journey.”
Julie van den Brink, Investment Associate, SHIFT Invest
