EB-X3: New electron-beam x-ray mask writer

The EB-X3 is an electron-beam mask writer designed to pattern x-ray masks w ith minimum feature sizes of 100 nm and below with good beam placement accu racy. The target patterning resolution is 50 nm, and a beam acceleration vo ltage of 100 kV is used to achieve it. This resolution has already been dem onstrated using the previous version of the writer, the EB-X2 (developed la st year), which also employs an acceleration voltage of 100 kV. On the othe r hand, the target placement accuracy for the EB-X3 is less than 10 nm, whi ch is more than three times smaller than that for the EB-X2. To improve the placement accuracy, the resolution of the laser measurement system was cha nged from lambda/128 (=5 nm) to lambda/1024 (=0.6 nm), and the address unit was set to 1 nm, which yields a reproducibility of mark detection of 4 nm (3 sigma) and a calibration accuracy for deflection distortion of 5 nm(\ me an \+3 sigma). In addition, the laser measurement system monitors five axes (X, Y, yaw, and pitch [X,Y]) and the results are fed back to position the beam. Furthermore, the signal fluctuations of the deflection, lens, and ali gner circuits were reduced, so that beam fluctuations are kept under 2 nm. The EB-X3 was delivered to the ASET Super-fine SR Lithography Laboratory in March 1999, and is now being evaluated for use in x-ray mask fabrication. The prospects are good for achievement of a placement accuracy of 10 nm (3 sigma) in the near future. (C) 1999 American Vacuum Society. [S0734-211X(99 )12006-7].