Line width optimization method for mixed arrangement of layers with different pattern densities

The invention relates to mask manufacturing, in particular to a line width optimization method for mixed arrangement of pattern layers with different pattern densities, which comprises the following steps of: photoetching the pattern layers with different pattern densities onto the same test plate, performing developing and etching treatment for the same time, and calculating an initial photoetching energy compensation value corresponding to each pattern layer; respectively photoetching the pattern layers with different pattern densities to the same test plate, carrying out photoetching energy compensation according to the initial photoetching energy compensation value corresponding to each pattern layer, and carrying out developing and etching treatment for the same time; adjusting the photoetching energy compensation value of each layer until an end condition is met, and obtaining an optimal photoetching energy compensation value corresponding to each layer; according to the pattern density and the optimal