Blind vias and buried vias are two advanced via technologies in multilayer PCBs, designed to solve the problem of limited wiring space in high-density designs, but they differ significantly in structure, manufacturing process, and application scenarios. Both types avoid the space waste caused by through vias that penetrate the entire board, but their connection modes and visibility distinguish them fundamentally, making them suitable for different product requirements.

A blind via is a hole that connects the outermost layer of the PCB to one or more inner layers without penetrating the entire board thickness, visible only from one side of the board—hence the name "blind". Its key characteristic is that it links the external layer (where surface-mounted components are soldered) to the inner layers, which helps save board space and reduce signal path length, thereby improving signal integrity. The aspect ratio (drill diameter to hole depth) of blind vias is usually required to be 1:1 or larger to ensure plating reliability. Manufacturing blind vias requires specialized processes such as laser drilling or controlled-depth mechanical drilling, with strict control over hole depth to avoid damaging the non-target inner layers. They are widely used in high-density designs such as mobile phones and tablet PCs, where compact size is a priority.

In contrast, a buried via is a hole that connects two or more inner layers without reaching the outermost layers, making it completely invisible from both sides of the board. It is located entirely inside the PCB, which maximizes the utilization of surface space and further improves wiring density. Buried vias require a more complex manufacturing process: inner layers are first drilled and plated, then laminated with other layers, so precise alignment of inner layers is critical to avoid via misalignment. Unlike blind vias, buried vias do not involve the outermost layers, making them ideal for PCBs with high layer counts and complex inner-layer connections, such as industrial control boards and high-end communication equipment. In terms of cost, buried vias are more expensive than blind vias due to their more complex lamination and alignment requirements, while both are more costly than traditional through vias.