A printed circuit board (PCB) includes an insulating layer with an upper surface and a lower surface opposite to the upper surface; a first conductive pattern on the upper surface of the insulating layer; a second conductive pattern on the lower surface of the insulating layer; an aluminum pattern that covers at least a portion of an upper surface of the first conductive pattern; and a first passivation layer that covers at least a portion of sides of the first conductive pattern and that prevents diffusion into the first conductive pattern.