Slide 1: Controlling Temperature of High-Power A.I. Devices
5/1/26 Controlling Temperature of High-Power A.I. Devices Ernest Blanco Systems engineer May 5, 2026 Page 1 Cohu Confidential
Slide 2: A.I devices are built different
A.I devices are built different ❑ Large footprints pushing limits of JEDEC tray size ❑ High power during test measured in multiple kW ❑ Many new challenges for final test Sufficient power to cook a Curry Laksa! May 5, 2026 Page 2 Cohu Confidential
Slide 3: Socketing force
Socketing force ❑ High socketing forces ❑ > 10,000 balls / device today ● >300 [kg] socket force ❑ Redesign TU for higher loads ❑ Roadmap 1 metric ton May 5, 2026 Page 3 Cohu Confidential
Slide 4: Convex devices
Convex devices ❑ Devices are convex, not flat ❑ Heat can flatten devices ❑ Some tests are at ambient & colder temps 0.30mm Die 0 reference Device cross section Substrate Stiffener Measured convex device @ room temp May 5, 2026 Page 4 Cohu Confidential
Slide 5: Convex devices cont.
Convex devices cont. ❑ Geometry imperfection affects thermal contact area ❑ Good contact mandatory to pass tests ❑ Higher proportion of force pushing through heater ● >90% capability vs <20% in older designs Heater force Poor contact Nest force Good contact May 5, 2026 Page 5 Cohu Confidential
Slide 6: Temperature gradient
Temperature gradient ❑ More sensors in device → tougher gradient specifications ❑ Improved design and test methods to optimize heater gradient Test IR image 51mm x 51mm heater Gradient <2[C] @ 90[C] May 5, 2026 Page 6 Cohu Confidential
Slide 7: Multizone
Multizone ❑ Large device → good gradient is not enough ❑ Die zones have different thermal loads during test ❑ Developed multizone TU with independent control May 5, 2026 Page 7 Cohu Confidential
Slide 8: Multizone cont.
Multizone cont. ❑ Customizable TU zones to match die zone dimensions ❑ Enables better overall control of die temp ❑ Testing IR images, 130C and 145C zones May 5, 2026 Page 8 Cohu Confidential
Slide 9: TIM
Good TIM is like good tires TIM ❑ Final test pushes TIM technology past its intended use ❑ Extensive evaluations & testing of next gen TIMs Most capable 4x4 vehicle ● Low thermal resistance, long lasting Still needs good tires otherwise & serviceable in the field performance will suffer! ❑ More cust
Slide 10: Static & dynamic optimization
Static & dynamic optimization Static power test Dynamic power test • >4[kW] device power steady state • Device temp within guard band >500[W] power step uneventful to device temp • Low thermal resistance stack up • Good control of >2[kW] power step! • Tj rise <10[C] • Control system reacts in 1-2 [m
Slide 11: The customer
The customer ❑ Some customers provide limited info on new applications ❑ Best results are with close cooperation with customer ● Detailed test & device specs ● Roadmap & design reviews ❑ Aviation analogy ● 787 → Design based on latest feedback & cooperation ● A380 → Design based on old ideas ● 787 c
Slide 12: Results
Results ❑ When all challenges are solved effectively: Tj rise controlled to good levels ● Beautiful performance graphs Dynamic high-power steps >2[kW] Peak power >4[kW] ● Products passing final test ❑ Enable the A.I revolution to continue to scale May 5, 2026 Page 12 Cohu Confidential
Slide 13: Thank you
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