Definition

Copper weight describes copper foil thickness using the weight of copper in one square foot. Standard weights are 0.5 oz (18 µm), 1 oz (35 µm), and 2 oz (70 µm). Heavier copper carries more current and dissipates heat better but limits fine-feature resolution. Plating adds ~25 µm to the finished copper thickness. High-current applications may use 3-10 oz copper, requiring special processing. Trace width tables for current capacity are based on copper weight and temperature rise.