Modeling method of phase shift mask in photolithographic process

The invention belongs to the field of integrate circuit photolithography, relating to a modeling method for processing phase shift mask in parallel. In the method, the mask is divided into N numbered vertical reticle mask structures along the longitudinal direction on the vertical juncture of the metal and the quartz of the mask to cause the dielectric constant of the adjacent vertical reticle mask structure to have different distributions on the vertical direction. The characteristic function and the characteristic value of the electric field of the characteristic vertical reticle mask structure are calculated with a spectral element method based on non-continuous Galerkin, and serve as the electric component of the vertical reticle mask structure represented by the primary function; in the horizontal direction, Schwartz iteration is adopted to solve the electric field equation and the boundary condition of N numbered vertical reticle mask structures; in each iteration, the electric field calculation task of N numbered vertical reticle mask structures is distributed to a plurality of calculation nodes to be finished in parallel; and the left and right boundary conditions of each vertical reticle mask structure adopt the solution of the adjacent vertical reticle mask structure in the previous step. The invention has the characteristics of high precision and parallel calculation and can handle the modeling of the practical large-scale phase shift mask of any structure.