Two-dimensional spatial-phase-locked electron-beam lithography via sparse sampling

We report a new mode of spatial-phase-locked electron-beam lithography base d on alignment of each e-beam deflection field to a fiducial grid on the su bstrate. Before exposing the pattern in a given field, the fiducial grid is sparsely sampled with the electron beam at a subexposure dose. These sampl es form a two-dimensional moire pattern that is analyzed to calculate field shift, scale, rotation, nonorthogonality, and trapezoidal distortion. Expe rimental verification of the approach was carried out with a scintillating fiducial grid quenched by interference lithography. Despite a Door signal-t o-noise ratio, we achieved sub-beamstep field-stitching and pattern-placeme nt accuracy. (C) 2000 American Vacuum Society. [S0734-211X(00)02206-X].