Provided is a device for generating an identification key using a process variation during a manufacturing process of a conductive layer. The device for generating an identification key may include a plurality of conductive layers designed so as to be formed in a first region within a semiconductor chip, the density in which the plurality of conductive layers are disposed in the first region being at least a first threshold value and not more than a second threshold value, the first and second threshold values being less than a minimum density according to the design rules for ensuring that all of the plurality of conductive layers are formed in the first region; and a reader which provides an identification key by identifying if, among the plurality of conductive layers, a previously designated first conductive layer has been formed.