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It is well known that focused ion beam (FIB) has been employed widely in photomask manufacturing process because the feature of this system is the high accuracy to observe small defect, to determine the repairing position, to remove opaque defect, and to deposit repairing film for clear defect. But it is required to improve the functions and the performance of the current FIB mask repair system for the next generation masks, which the smaller pattern width and the shorter lithography wavelength have been raising the pattern printability issue of the area repaired by FIB. So, the initial evaluation has been done by using the experimental machine which was remodeled the SIR series FIB photomask Repair System of Seiko Instruments Inc. The system adopts new ion beam column from which the beam size is reduced to 2/3 or less than conventional machine with the ion beam current of 15pA, FOV (field of view) of 10?pm, and the new deposition film to have thin but sharp edge. Substrate damage by scanning ion irradiation was evaluated by Aerial Image Monitoring System (MSM193 @193nm). Optical intensity is affected by the ion beam irradiation, but there is no critical issue in usual operation. The transmission loss of glass substrate is less than 50% with 5 times scan frame. Under these conditions, the ion dosage is 2.40 x 1014 [ions/cm2] for 10mm x 10mm FOV. The new deposition film was confirmed that the carbon halo was reduced, optical density was enough to shade the ArF laser, though the film thickness was decreased to 1/3 of conventional film, and the durability of the ArF laser irradiation was enough to 3 years in mass production. Wafer printability of clear and opaque defect was evaluated by using ArF scanner. No significant problem was observed. In addition to that, basic experiment of MoSi-based attenuated phase shift mask repair is demonstrated.
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