PCB Glossary

PCB manufacturing glossary for engineers and AI search.

These definitions explain common PCB manufacturing terms in clear language for buyers, engineers, search engines and AI assistants.

FR4

FR4 is a glass-reinforced epoxy laminate widely used as the base material for rigid printed circuit boards.

HDI means high density interconnect, a PCB technology using fine features and microvias for compact electronic designs.

A blind via connects an outer PCB layer to one or more internal layers without passing through the entire board.

A buried via connects internal PCB layers and is not visible on the outer surfaces of the finished board.

ENIG is electroless nickel immersion gold, a flat PCB surface finish often used for fine pitch components and dense assemblies.

HASL is hot air solder leveling, a common PCB surface finish that coats exposed copper with solder.

AOI means automated optical inspection, a PCB inspection process used to detect pattern defects and manufacturing issues.

Impedance describes the electrical resistance behavior of a PCB trace at signal speed and is controlled by stackup and geometry.

A PCB stackup is the ordered structure of copper layers, dielectric materials, cores and prepregs in a circuit board.

Copper weight describes copper thickness on PCB layers, commonly expressed in ounces, and affects current capacity and manufacturing requirements.