A magnetoresistive random access memory (MRAM), including multiple cell array regions, multiple MRAM cells disposed in the cell array region, a silicon nitride liner conformally covering on the MRAM cells, an atomic layer deposition dielectric layer covering on the silicon nitride liner in the cell array region, wherein the surface of atomic layer deposition dielectric layer is a curved surface concave downward to the silicon nitride liner at the boundary of MRAM cells, and an ultra low-k dielectric layer covering on the atomic layer deposition dielectric layer.