Definition

Copper pour (or copper fill) floods unused areas of a PCB layer with copper, typically connected to ground or power nets. Benefits include lower impedance for power distribution, improved thermal dissipation, reduced EMI (ground pours shield signals), and more even copper distribution for manufacturing (prevents warping, improves etching uniformity). Design considerations: set appropriate clearance to other nets (typically 0.2-0.3mm), use thermal relief connections to pads for solderability, and avoid isolated copper islands that can cause antenna effects. For RF designs, continuous ground pours under signal traces are essential for controlled impedance.