What’s plugged via on PCB Board?
A plugged via is a via hole in a PCB that is filled with a material—usually conductive or non-conductive epoxy-after the drilling process. This process is used to close the via opening for various technical or performance reasons. Unlike tented vias, which are simply covered with a solder mask, plugged vias are physically filled, providing enhanced protection and functionality.
Why Plugged Vias Are Used?
1.Prevent Solder Wicking: Like tenting, plugging prevents solder from wicking through the via during the assembly process. This is particularly important when the via is placed under a component pad in Surface Mount Technology (SMT).
2.Improved Thermal and Electrical Properties: Conductive-filled vias can enhance heat dissipation and electrical conductivity, making them useful in high-power or high-frequency applications. Non-conductive plugs, on the other hand, improve insulation and structural integrity without altering the electrical properties.
3.Protection from Contaminants: Plugging a via provides a hermetic seal, preventing moisture, dust, or other contaminants from entering the via hole and potentially affecting the board’s performance.
4.Strength and Reliability: Plugged vias help in strengthening the mechanical structure of the PCB, making it more resilient to stress, especially in multi-layer or high-density interconnect (HDI) PCBs, where vias are more numerous and smaller.
5.Facilitate Planar Surface: In applications where a flat surface is required (for example, via-in-pad designs), plugging the via helps ensure that no depressions or cavities are left that could disrupt soldering or lead to other issues during assembly.
What Types of Plugged Vias?
1.Conductive Plugged Vias: Filled with conductive materials such as copper or silver epoxy, these vias improve current carrying capacity and heat dissipation.
2.Non-Conductive Plugged Vias: Filled with non-conductive epoxy, these are used to enhance mechanical strength without affecting electrical characteristics.
3.Via-in-Pad Plated Over (VIPPO): In this technique, vias are plugged and then plated over to create a flat, planar surface, which is often necessary for BGAs (Ball Grid Arrays) and other fine-pitch components.
What Advantages of Plugged Vias?
- Prevents solder migration, making it easier to solder components reliably.
- Enhances thermal management in high-power PCBs.
- Improves board integrity and protects from environmental damage.
- Ideal for high-density boards, allowing designers to place vias under component pads without affecting assembly.
Plugged vias are often used in advanced PCBs, including those for automotive electronics, consumer electronics, medical devices, aerospace, and telecommunications industries. They are especially critical in high-frequency circuits, high-power designs, or HDI boards, where reliability and precision are paramount.
In conclusion, plugged vias offer both mechanical and functional benefits, providing superior reliability and performance in modern, high-density PCBs.
