The trends of electronics toward higher power, higher density, and 2.5D/3D integration are making thermal management ever more challenging. Conventional cooling solutions simply based on high thermal conductivity materials or heat exchangers dissipate the heat from a source to a sink in a uniform manner, but they are unable to guide the heat flow in a deterministic manner or optimize the heat transfer paths for complex packaging designs. The slow progress made in the field of heat transfer could be attributed to the relatively limited understanding of thermal transport and the shortcoming of 3D metamaterial designs to control heat transfer. Thermal metamaterials can effectively control heat flux and their unique heat guiding capabilities can lead to optimal solutions for complex packaging scenarios. Although there have been fundamental studies on the possibilities of developing thermal metamaterials and manipulating heat flows in 3D structures, but most of those designs are not given practical considerations for packaging thermal management. Here, we investigate the development of novel 3D architected thermal metamaterials by utilizing state-of-the-art additive manufacturing techniques which would enable breakthroughs in heat guiding and efficient cooling of next-generation electronics. By combining topology optimization and thermal transport models, a numerical algorithm was developed to optimize heat guiding in complex packaging scenarios. We solved the density-based topology optimization problem for 3D copper heat guiding structures. An objective volume fraction of 50% was chosen for our computations which is the representative value for the volume fraction of utilized copper in circuit boards of electronics. For evaluating the performance of the optimized heat guiding structures, a reference design with a 50% volume fraction of the simulation domain was created. Our simulation results demonstrated a maximum of 44% reduction in the thermal resistance of the optimized heat guiding structure compared to its corresponding reference design. This reduction in thermal resistance translates to a 21% reduction in the hotspot temperature of the heat guiding structure designed by the topology optimization approach. Furthermore, we leveraged the additive manufacturing of metallic structures using a Selective Laser Melting (SLM) technique and characterized the thermal properties of 3D manufactured structures to predict the impact of heat guiding in complex packaging scenarios. By utilizing a thermal evaluation method based on infrared thermography, we demonstrated a unique control over thermal conductivity depending on the architecture in 3D manufactured structures. The outcomes of this work will present thermal metamaterials as a novel platform to realize 3D architected packaging structures and as a building block of future thermal management systems.


3d Architected Packaging Structures for Thermal Management

Division / Sponsors: 
Electronic & Photonic Packaging Division (EPPD)

Paper Proceedings: https://asmedigitalcollection.asme.org/InterPACK/InterPACK2020/volume/84041

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