noun
copper foil
Thin sheet of copper, often used in electroplating, shielding, or crafting.
プリント基板には銅箔が使われている。
Copper foil is used in printed circuit boards.
noun
copper layer
Specifically the copper conductive layer in printed circuit boards.
この基板の銅箔は厚さが35ミクロンだ。
The copper layer on this board is 35 microns thick.