Apparatus and method for generting physical unclonable function by modifiying photo mask of semiconductor process

Causing unpredictable part process failure in the semiconductor process is a method of generating the PUF is provided. If it does not violate the semiconductor design rule in the design stage, even, it is possible to print a first at least a second mask pattern distort the size and / or shape of the mask window with the first mask pattern designed. And it may be generated by the PUF using a photomask including a mask pattern for the print second photolithography to perform.