Pattern formation material, pattern formation method, and exposure mask fabrication method

An exposure mask fabrication method using a pattern formation material for electron beam lithography, said pattern formation material comprising an alkali-soluble resin and a photoacid generator which generates an acid when irradiated with an electron beam, said pattern formation material further comprising first and second dissolution inhibiting groups each of which has a capacity of inhibiting dissolution of said alkali-soluble resin in an alkali solution and loses the capacity upon application of an acid, said first dissolution inhibiting group increasing a sensitivity of said pattern formation material when left to stand in a vacuum after irradiation with an electron beam, and said second dissolution inhibiting group decreasing the sensitivity of said pattern formation material when left to stand in a vacuum after irradiation with an electron beam, comprising:

• determining a ratio of said first dissolution inhibiting group to said second dissolution inhibiting group such that a size of an alkali-soluble portion, which is a portion made soluble in said alkali solution when said pattern formation material is irradiated with an electron beam, is substantially held constant independently of a standing time in a vacuum;
• forming a light-shielding film on one principal surface of a transparent substrate;
• forming a photosensitive film by coating the surface of said light-shielding film with said pattern formation material containing said first and second dissolution inhibiting groups at the determined ratio;
• performing electron beam writing on said photosensitive film in a vacuum;
• forming a patterned film by developing said photosensitive film subjected to the electron beam writing;
• and
• etching said light-shielding film by using said patterned film as an etching mask.