Analysis of Cooling Performance of Hybrid Heat Sink According to Channel Geometries of Thermo Compression Bonding Heater for HBM Fabrication

High Bandwidth Memory (HBM) fabrication requires highly reliable Thermo Compression (TC) bonding, where rapid heating and cooling of ceramic pulse heaters are critical to bonding quality. While heating characteristics have been widely studied, cooling strategies remain insufficiently explored. This study numerically investigates hybrid cooling channels that combine jet impingement with micro-channel flows to enhance transient cooling performance. Three geometries-Aligned, Staggered, and Zigzag-were modeled using transient computational fluid dynamics with the Realizable k-ε turbulence model. Cooling effectiveness was evaluated through heater temperature, Nusselt number, and heat flux. Flow structures and cross-sectional Nusselt number distributions along the z-axis were also examined to identify mechanisms governing heat transfer. Results showed that the Zigzag configuration with a 30 ° angle (Z30) was the only case reaching the target temperature of 373 K within 10 s, achieving an 8.9 % improvement over the reference design. Although Z30 exhibited the highest total heat removal, Z20 achieved slightly higher area-normalized heat flux due to its smaller cooling area, indicating a trade-off between absolute cooling capacity and surface efficiency. Flow analysis revealed that periodic separation and reattachment in the Zigzag channel continuously disrupted the thermal boundary layer, sustaining higher Nusselt numbers along the z-axis. These findings highlight the importance of channel geometry, with Zigzag layouts offering a promising pathway to improve TC bonding reliability in next-generation HBM packaging.