Resist-Free E-beam Lithography for Patterning Nanoscale Thick Films on Flexible Substrates

Resist-based lithographic tools, such as electron beam (e beam) and photolithography, drive today's state-of-the-art nanoscale fabrication. However, the multistep nature of these processes, expensive resists, and multiple other consumables limit their potential for costeffective nanotechnology. Here, we report a one-step, resist-free, and scalable methodology for directly structuring thin metallic films on flexible polymeric substrates via e-beam patterning. Controlling e-beam dose results in nanostructures as small as 5 nm in height with a sub micrometer lateral resolution. We structure nanoscale thick films (100 nm) of Al, TiN, and Au on standard Kapton tape to highlight the universal use of our nanopatterning methodology. Further, we utilize direct e-beam writing to create various high-resolution biomimetic surfaces directly onto ceramic thin films. In addition, we assemble architectured mechanical metamaterials comprising crack traps, which confine cracks and prevent overall material/device failure. Such a resist-free lithographic tool can reduce fabrication cost dramatically and may be used for different applications varying from biomimetic and architectured metamaterials to strain-resilient flexible electronics and wearable devices.

Automated summary

This study reports a resist-free and scalable method for directly structuring thin metallic films on flexible polymeric substrates via e-beam patterning. Nanostructures as small as 5 nm in height with a sub micrometer lateral resolution can be achieved by controlling e-beam dose. The resist-free lithographic tool can dramatically reduce fabrication cost and be used for different applications including biomimetic surfaces, architectured metamaterials, strain-resilient flexible electronics, and wearable devices.