Via (electronics)

A via is a vertical electrical connection between different layers of conductors in a physical electronic circuit.

In IC

In integrated circuit design, a via is a small opening in an insulating oxide layer that allows a conductive connection between different layers. A via on an integrated circuit is often called a through-chip via. A via connecting the lowest layer of metal to diffusion or poly is typically called a "contact".

Often, redundant vias are added, where possible, to improve the reliability of the circuit and enhance the manufacturing yield.

In PCB

Different types of vias:
(1) Through hole.
(2) Blind via.
(3) Buried via.
The grey and green layers are non-conducting, while the thin orange layers and vias are conductive.

In printed circuit board. It consists of two pads, in corresponding positions on different layers of the board, that are electrically connected by a hole through the board. The hole is made conductive by electroplating, or is lined with a tube or a rivet. High-density multi-layer PCBs may have microvias: blind vias are exposed only on one side of the board, while buried vias connect internal layers without being exposed on either surface. Thermal vias carry heat away from power devices and are typically used in arrays of about a dozen.

A via consists of:

1. Barrel — conductive tube filling the drilled hole
2. Pad — connects each end of the barrel to the component, plane or trace
3. Antipad — clearance hole between barrel and no-connect metal layer

Gallery

Plated-through holes, in this section there are eight on a multilayer board (hugely magnified)   Double layered plating in CAD. Vias makes EDA placement possible. Bottom layer – Red Top layer – Blue   Plating of plated-through holes: Above – Top layer Down – Bottom layer

Cut section of a multilayer via   The small metallic circles are vias

See also

• Printed circuit board (PCB)
• Through-hole technology (THT)
• Surface-mount technology (SMT)
• Through-silicon via (TSV)