Abstract: The present invention relates to a monitor method for quality of metal Antireflection Coating (ARC) layer and, more particularly, to a fast and accurate monitor method for quality of metal ARC layer. By using of immersing a silicon wafer comprising an ARC layer into an acidic (such as a developer) or an alkalescent solution for about 200-300 seconds, according to the present invention, at weak points of the metal ARC layer there occur voids (defects) due to a Galvanic cell effect enhanced by these chemical solutions and then how many defects can be counted by a wafer defect inspector such as a KLA instrument so that quality of the metal ARC layer can be monitored by this defect number. Besides, Since the silicon wafer used as a sample for the wafer defect inspector simply comes from a production line, i.e. a developing process, rather than from other additional processing, said method allows for fast and accurately monitoring quality of the metal ARC layers.