Imaging performance of mesh supported pellicle for extreme ultraviolet lithography

Abstract

Extreme ultraviolet (EUV) lithography is the first candidate for 16 nm half pitch devices and EUV pellicle is needed for mask defect control. In order to check the effect of the pellicle on the EUV patterning, aerial image simulation including the meshed pellicle is performed. We found that the overall transmission drop caused by the pellicle structure might change the line width even though the contrast of the aerial image remained almost the same. The aerial images of 16 nm line and space pattern with various pellicle structures are studied to see the effect of the meshed pellicle variables. Smaller mesh height and width, and larger mesh pitch of the pellicle support are preferred since transmission is better.

Impact of the non-uniform intensity distribution caused by a meshed pellicle of extreme ultraviolet lithography

“…The physical optics model can produce a result as accurate as the rigorous electromagnetic field (EMF) model that uses the pseudo-spectral time-domain (PSTD) method [19,20]. All the non-uniformity simulation results below were obtained from the physical optics simulation.…”

“…Most of the light passing through the mesh is absorbed and diffracted, resulting in an irregular intensity distribution on the mask; this may consequently cause pattern deformation [19]. Nevertheless, the irregular intensity distribution is affected only by the structural characteristics of the mesh, so it can be avoided using suitable mesh parameters.…”