A method for fabricating a phase shifting mask suitable for positive photoresist process. The method includes the steps of: (a) forming a plurality of opaque layer patterns (44) in an array at a fixed interval from each other in their width direction on a substrate (41); (b) coating an interlayer (45) on and covering the opaque layer patterns; (c) forming interlayer patterns (45) on the substrate at both longitudinal sides of each opaque layer pattern by etching the interlayer; (d) forming a plurality of insulation films (46) on the substrate between adjacent pairs of the opaque layer patterns on which the interlayer patterns are formed; (e) removing the remaining interlayer under each of the insulation films; and (f) forming a phase shifter (47) having a ninety degree area (47-2) in a region where the interlayer has been removed and a one hundred and eighty degree area (47-1) in the remainder of the region by heating the insulation film.
