PCB散热垫中的散热孔通常用于将热量从器件传导出去，并有效地将热量从PCB的顶部铜层传递到内部或底部铜层或外部环境。

Thermal vias in the PCB thermal pad are typically used to conduct the heat away from the device and to transfer effectively the heat from the top copper layer of the PCB to the inner or bottom copper layer or to the outside environment.

相关文章： THE IMPACT OF VIA AND PAD DESIGN ON QFN ASSEMBLY

This paper discusses our study on the impact of the via size and the via design on QFN voiding and solder protrusion. Do small vias prevent the solder from flowing onto the other side? How should via be designed? Which via type will have less voiding issue? A comprehensive experiment was designed in trying to answer these questions. Different QFN types, via design, via sizes, via pitches and stencil design were studied using three different board thicknesses: 1.6mm, 2.4mm and 3.2 mil thick.