Large area metalenses are on the horizon.
In this section, we briefly discuss the presented technique of VSB/CP e-beam writing in comparison with two other contemporary high-resolution lithographic patterning approaches: multibeam e-beam lithography, also known as complementary electron beam lithography (CEBL),16 and optical lithography.
Today’s optical lithography tools are basically well able to address the feature-sizes of the elements presented in the previous section. The exposure in those tools is based on a demagnified imaging of a pattern containing photomask. With this parallel approach, optical lithography is always much faster than any direct-write technique. The central question for making a choice between optical lithography or VSB/CP-based e-beam lithography is, therefore, the effort needed to achieve the required optical performance. For the optical lithography, this is related to the quality of the mask. A high-resolution optical pattern may require a very fine approximation of the mask pattern, leading to large writing times in a mask shop and thus to considerable costs. Consequently, the choice between the different techniques must include considerations on the number of elements required and the price for which the final consumer product can be sold. This cannot be generalized.
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