Methods for extending working distance using modified photonic crystal for near-field lithography

Abstract

Near-field lithography has evident advantages in fabricating super-resolution nano-patterns. However, the working distance (WD) is limited due to the exponential decay characteristic of the evanescent waves. Here, we proposed a novel photolithography method based on a modified photonic crystal (PC), where a defect layer is embedded into the all-dielectric multilayer structure. It is shown that this design can amend the photonic band gap and enhance the desired high-k waves dramatically, then the WD in air conditions could be extended greatly, which would drastically relax the engineering challenges for introducing the near-field lithography into real-world manufacturing applications. Typically, deep subwavelength patterns with a half-pitch of 32 nm (i.e., λ/6) could be formed in photoresist layer at an air WD of 100 nm. Moreover, it is revealed that diversified two-dimensional patterns could be produced with a single exposure using linear polarized light. The analyses indicate that this improved dielectric PC is applicable for near-field lithography to produce super-resolution periodic patterns with large WD, strong field intensity, and great uniformity.

Advances in lithographic techniques for precision nanostructure fabrication in biomedical applications

“…Maintaining a constant nanometer-scale working distance between presents an engineering challenge, particularly when considering any variations in the roughness of the substrate and the mask, with any deviations in this working distance across the substrate resulting in loss of resolution and fidelity. Overcoming these challenges is crucial for its successful industrial integration [ 161 , 162 ]. However, given the existence of commercially available lithographic systems like EUVL and EBL, which already deliver high-resolution nanostructures cost-effectively for applications such as biosensors and cell studies, the time and cost involved in surmounting these engineering challenges could potentially present a less attractive proposition.…”