Merging focused ion beam patterning and optical lithography in device and circuit fabrication

Combining optical lithography and focused ion beam (FIB) patterning in direct‐write device and circuit fabrication by generating large features optically and small features with the FIB can significantly reduce beam writing time. Our approach to FIB pattern definition is ideally suited for alignment to optically patterned features and takes full advantage of the lithographic and implantation capabilities of the FIB. Optical and FIB patterns are designed simultaneously in the very large scale integrated layout tool magic, [magic, Report No. UCB/CSD 85/225 University of California, Berkley (March 1985)]. We have developed a software package magtofib [James E. Murguia, Christian Musil, Mark Shepard, Sasan Zamani, magtofib, Massachusetts Institute of Technology (1989)] which takes its input from the magic data file and converts it to FIB stage and beam commands. The FIB is aligned by operating in scanning ion microscope mode and finding the centroid of an optically produced die alignment mark. Since the coord...