Via (electronics)
Encyclopedia
A via is a vertical electrical connection between different layers of conductors in a physical electronic 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 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:
In IC
In integrated circuitIntegrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...
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
Printed circuit board
A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring...
. 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
Electroplating
Electroplating is a plating process in which metal ions in a solution are moved by an electric field to coat an electrode. The process uses electrical current to reduce cations of a desired material from a solution and coat a conductive object with a thin layer of the material, such as a metal...
, or is lined with a tube or a rivet
Rivet
A rivet is a permanent mechanical fastener. Before being installed a rivet consists of a smooth cylindrical shaft with a head on one end. The end opposite the head is called the buck-tail. On installation the rivet is placed in a punched or pre-drilled hole, and the tail is upset, or bucked 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:
- Barrel — conductive tube filling the drilled hole
- Pad — connects each end of the barrel to the component, plane or trace
- Antipad — clearance hole between barrel and no-connect metal layer
Gallery
See also
- Printed circuit boardPrinted circuit boardA printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring...
(PCB) - Through-hole technologyThrough-hole technologyThrough-hole technology, also spelled "thru-hole", refers to the mounting scheme used for electronic components that involves the use of leads on the components that are inserted into holes drilled in printed circuit boards and soldered to pads on the opposite side either by manual assembly by...
(THT) - Surface-mount technologySurface-mount technologySurface mount technology is a method for constructing electronic circuits in which the components are mounted directly onto the surface of printed circuit boards . An electronic device so made is called a surface mount device...
(SMT) - Through-silicon viaThrough-silicon viaIn electronic engineering, a through-silicon via is a vertical electrical connection passing completely through a silicon wafer or die...
(TSV)