2 Thermal Vias in Power PCB design

Usually, power PCB designs focus on improving thermal performances by increasing the copper area or adding ground planes in a multilayer boards. Thicker copper planes and wider traces resulting in low resistance and low parasitic inductance also helps to dissipate heat in the same size board area.

However, one of the most effective ways to propagate heat through the PCB is to use vias. Thermal vias are commonly used in PCBs as a mean to dissipate heat vertically from surface mount components to the PCB inner layers. Vias are simple mechanical drillings made to penetrate the PCB and thereby connect multiple layers in the PCB.

Figure 2-1 shows the different type of vias typically used in the PCB industry, they also differ in terms of use and costs.

Through-hole vias are the most used and cheapest to manufacture. There are micro vias called buried vias: which can connect the internal layers without being exposed to outer air, and blind vias: which can connect the internal layers and are exposed on one side of the board. Both buried vias and blind vias provide only a partial connection between the PCB layers and add a degree of complexity to the design which results in a more expensive PCB design.