A substrate having single patterned metal layer includes a patterned base having at least a plurality of apertures, the patterned metal layer disposed on the patterned base, and a first surface finish layer. Parts of the lower surface of the patterned metal layer are exposed by the apertures of the patterned base to form a plurality of first contact pads for downward electrical connection externally, and parts of the upper surface of the patterned metal layer function as a plurality of second contact pads for upward electrical connection externally. The first surface finish layer is disposed at least on one or more surfaces of the second contact pads, and the first surface finish layer is wider than the second contact pad beneath. A package applied with the substrate disclosed herein further comprises at least a die conductively connected to the second contact pads of the substrate.