buried vias are used to connect internal layers of a PCB

Buried vias are a common specialized hole structure in multilayer printed circuit boards. They exist solely between the internal layers of the PCB and do not extend to the board’s surface. In other words, buried vias connect only two or more internal layers within a multilayer board, with no visible openings to the outer layer surfaces.

Key Characteristics of Buried Vias

1. Connection method: Connects only internal layers to internal layers. no visible openings to outer layers.
2. Visual Characteristics: Buried vias are invisible from the PCB’s exterior surface as they are entirely enclosed within the board’s interior.
3. Manufacturing Complexity: The fabrication process is more intricate than standard through-holes or blind vias, requiring layer-by-layer drilling and plating of inner layers prior to lamination.

Applications of Buried Vias

1. Enhance PCB routing density and conserve surface layer space.
2. Meets miniaturization and high-performance demands for premium electronics like servers, communication equipment, and smart terminals.
3. Commonly used in HDI, High-Density Interconnect board designs, combined with blind vias and through-holes to enhance design flexibility.