About this document
Advanced packaging demands a fast reaction at the bond interface while allowing an ever lower thermal budget for the structures around it. The two demands conflict. Instead of heating and cooling the whole assembly, this brief sets out an approach that switches where energy couples in space and time, applied to two processes: HBM bonding and CPO integration.
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Summary
Advanced packaging demands a fast reaction at the bond interface while allowing an ever lower thermal budget for the surrounding structures. Heating and cooling the complete assembly cannot satisfy both. This brief sets out an approach that switches the point of energy coupling in space and time, applied to HBM bonding and CPO integration. It is the Korean edition of the ISMP 2026 abstract, with the English original reproduced at the end of the document.
Conclusion
The Thermal Clutch switches the path along which heat flows; the Optical Clutch switches the path along which light is absorbed. The physical quantity differs but the structure is the same: bonding is redefined as a problem of delivering energy selectively to the interface alone. In HBM thermocompression bonding, the thermal mass coupled to the heater during the heating stage is minimized, and immediately after bonding a high-conductivity AlN thermal receiver is engaged against the back of the heater. From that point cooling occurs by solid conduction rather than air convection. The heat-loaded receiver is then disengaged and regenerated at a separate heat sink, and because that regeneration happens while the next die is being picked and aligned, the time spent shedding heat does not enter the bonding takt time. In a validation run on a modified production TCB heater, ten repeated cycles with an 11mm×11mm HBM3E die brought the bonding cycle from 7.0 seconds to 3.4 seconds, a 51% reduction. In CPO integration the same principle is realised with light. Light in the 1.45-1.60 micrometre band has less energy than the silicon bandgap, so it passes through the Si PIC with almost no loss and is absorbed only when it reaches the thin interfacial layer at the bond line between the EIC and the PIC. With a short optical pulse, heating finishes before heat spreads into the Si PIC body, the waveguides, the electronic die or the surrounding dielectrics. Seen this way, speeding up HBM assembly and all but eliminating the bulk thermal budget in CPO bonding are not two different problems.
Topics
- Thermal control
- HBM
