3-D e-Beam Lithography
A growing demand for fabrication of 3D nanostructures like diffractive optical elements or computer generated holograms require a complex data-preparation flow to define the post-development resist thickness at all positions. Since resist thickness is a function of the development process (as described by the contrast curve and the absorbed energy at a given position) and the layout condition, experimental trial & error optimization is not feasible as the number of parameters and interactions is very large.
The BEAMER 3D PEC module makes 3D e-beam lithography very easy. The user can import the experimentally determined contrast curve of the resist development process, the PSF (e.g. from Monte Carlo simulation) and the layout with the target resist thickness encoded as layers. BEAMER will automatically calculate the target absorbed energy and apply PEC for computing the required applied doses. The result is a dose corrected layout, which can be exported to the machine format and exposed.
In addition to 3D lithography for singe layer resists, BEAMER 3D PEC also supports multilayer resist processes for T-Gate or Bridge applications. Multi-layer resist processes will be described in a separate application note.