Reduction of long range fogging effect in a high acceleration voltage electron beam mask writing system

We have developed an antireflecting plate with a novel structure to reduce the long-range fogging effect, which is especially serious in mask writing by a high acceleration voltage electron beam mask writing system. This stru cture is characterized by an array of holes whose axes converge to the beam irradiation position. These holes can efficiently absorb the electrons sca ttered at a reticle by avoiding the collision of the electrons with the inn er walls. The reflectance of this structure is about 30% of that of the pla ne structure for 30 keV electrons, whereas that of a parallel hole array st ructure is about 40%. The fogging effect was evaluated in a high accelerati ng voltage (50 kV) electron beam mask writing system equipped with this new antireflecting plate, and nm-level global uniformity in pattern size was a chieved. (C) 1999 American Vacuum Society. [S0734-211X(99)10606-1].