A method for forming a semiconductor device package substrate including a fiducial mark is provided. The method of forming the package substrate includes forming a dielectric layer over a lower portion of the package substrate. A metal layer is formed over a fiducial region of the package substrate. The metal layer is etched to form a first signal line in the fiducial region. A passivation layer is formed over the first signal line. The passivation layer is etched over the first signal line to form a fiducial mark.