Simulation of Self-Heating of Printed Interconnects for Thermal Design

Self-heating of electric components is an important design criterion for electronic circuits. Using additive manufacturing processes like low temperature printing of interconnects to replace conventional cables, is beneficial in terms of customizability and flexibility. However, the materials used to print interconnects often have lower conductivities than conventional bulk-metal leads. This causes an increase of temperature for interconnects with equal cross-section due to the higher power density. Using a heat spreading substrate can be advantageous for cooling the interconnects and therefore saving material which otherwise would be needed to compensate the higher resistivity. In this work, an analytical model is used to calculate the temperature of printed interconnects based on their cross-section profile and the free space on the substrate. The model allows to vary the cross-section geometry by adding up multiple profiles in order to emulate interconnects printed with multiple dispense cycles on top or next to each other. Therefore, it can be used to find suitable print configurations for different power requirements. The results are verified by comparison with FEM simulations and experimentally obtained data.