A system for reducing clock speed and power consumption in a network chip. Each data mark is arranged for modifying a portion of an optical reading beam incident thereon. An NMR signal measuring apparatus amplifies the NMR signal from the probe coil, and executes an AD conversion so as to determine an NMR spectrum signal, and an NMR signal analyzing apparatus compares the NMR spectrum signal. Consequently, the thickness of the lower portion of the plastic layer becomes greater, thereby preventing cracks from occurring on the semiconductor chip.