"One demonstrated and promising approach is to modify the interface surfaces by implementing hierarchical mini- and micro-channel structures in the solid interface to control the bond line formation during assembly. This technology is called hierarchically nested channels (HNC). "
"Over 20 materials have been characterized by IBM with HNC and BLT reductions from 20 to 90 % have been found. The technology was first developed as a TIM1 (silicon chip to lid) solution, but current work [1] shows greater benefit on larger interfaces like power electronics modules. Particularly interesting for Nanopack is the combination of HNC with an Electrovac TIM material containing carbon nano-fibers to augment heat conduction. The figure on the right shows that HNC has significant effect on the final BLT and squeeze time for low-viscosity screen-printable non-adhesive formulation tested. Final BLT for the tested paste is reduced by 78% and reached 98% faster than the non-HNC case. HNC may be integrated at different packaging levels and for different interface sizes. The simplicity of the HNC designs allows applying different patterning methods to a broad range of materials. "
For more on how HNC relates to heatsinks, see this article on Electronics-cooling. [EUROPA.EU] via [Frostytech.com]