The invention provides a manufacturing method of a
mask plate, which comprises the following steps: providing a substrate, and forming a main pattern and a
cutting channel forming region arranged at the periphery of a main pattern region on the substrate; and forming an
overlay alignment mark and a redundant graph in a
cutting channel graph region, wherein the redundant graph surrounds the overlayalignment mark. Under the condition that the
overlay alignment mark is arranged, the redundant graph is additionally arranged in the
cutting channel forming region of the
mask plate; the
overlay alignment mark and the redundant graph can be subsequently transferred to the surface of the
wafer together; according to the invention, the
etching stress on the surface of the
wafer when the
wafer is etched to obtain the dense lines corresponding to the overlay alignment marks is dispersed, so that the breakage of the dense lines in the
etching process is avoided, the damage to the overlay alignmentmarks is reduced, the
etching stability is improved, the measurement
noise of overlay alignment is reduced, and the product yield is improved.