This paper proposes a three-face utilized heat sink design for a 3-D integrated SiC-based 75 kVA Intelligent Power Stage (IPS). The structure enables maximum utilization of the heat sink where all three faces of the heat sink are utilized to hold the power devices. For loss estimation from power devices, Model Based Optimization (MBO), an efficiency calculation algorithm, is developed to estimate power loss at 75 kVA for the IPS, which needs to be dissipated efficiently by the heat sink. Further for simplified and cost-effective heat sink fabrication, cylindrical holes are considered to replace conventional fins. A parametric analysis is performed using SOLIDWORKS to determine optimum number of holes for efficient heat spreading and airflow. The simulation results show that heat sink based on cylindrical holes is effective in keeping the MOSFET die temperature under 120 °C in continuous operation, with 35% reduction heat sink volume compared with the conventional single-sided cooled design.