Wafer-level thermal management that unlocks next-generation semiconductor and photonic performance
CoolSem’s patented WaLTIS® platform replaces the conventional substrate with a high-thermal-conductivity carrier. The result is lower thermal resistance and greater device efficiency and reliability across RF, power, photonic, and high-performance computing applications
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How we redefine semiconductor performance
High heat density
Chips generate moreheat than ever, limiting performance and reliability.
power causes heat buildup
Thermal limits of
conventional substrates
Standard substrates cannot keep up with next-gen demands.
Thermal bottlenecks in substrate
Complex integration
challenges
Multi-layer, multi-material chips require smarter wafer-level thermal solutions.
complex cooling systems
Efficient
heat removal
WaLTIS®’s high-thermal-conductivity carrier delivers up to 15× lower thermal resistance, boosting performance and reliability.
remove thermal barrier
CTE-matched
substrate replacement
Replaces conventional substrates while minimizing mechanical stress from temperature cycling for long-term reliability.
patented WaLTIS® technology
Dielectrically
neutral integration
Integrates seamlessly into multi-material designs without affecting RF performance or signal integrity.
unlocked power and efficiency
mission & vision statements
01
Our mission statement
At CoolSem, we deliver wafer-level thermal management solutions that improve performance, reliability, and energy efficiency in RF, power, photonic, and computing devices.
02
Our vision
We envision a world where innovation outpaces thermal limits — where chips run cooler, systems last longer, and every design pushes efficiency further.
Founding team
04
André van Geelen
ceo
PhDin III-V materials with extensive experience in semiconductors and photonics.Formerly at Philips, NXP, EPCOS, JDSU, and Qualcomm, André had a senior role atThreeFive Photonics (exit ASIP) and led Antenna Tuners (exit Qualcomm). Known for his pragmatic and intuitive approach to technology.
Robbert van der Waal
cso
Seasonedleader in semiconductors and photonics, with different roles including GeneralManagement at Philips MEMS & Micro Devices and Philips Laser Sensors, andin international product marketing management for RF at NXP. Focused on people,business and strategy.
Kees Steenbergen
cOo
PhD in opto-electronics with extensive experience in semiconductors and wireless systems. Co-founder of ThreeFive Photonics (merged with ASIP) and operations lead at GreenPeak (exit Qorvo). Held senior roles at Qorvo and Pharrowtech, known for combining analytical rigor with hands-on execution.
Pieter Heersink
cCo
Experienced entrepreneur and strategic advisor with expertise in high-tech ventures. Founder & CEO of TicTag, HighTechXL start-up coach, and former consultant at IG&H and Capgemini. Experienced in M&A at Achmea, known for creativity, connecting people, ideas, and opportunities.
