Freestanding Photoresist Film: A Versatile Template for Three‐Dimensional Micro‐ and Nanofabrication

Abstract

Ultrathin freestanding films with well-defined micro/nanostructures and robust mechanical properties are applied in many engineering applications including microelectronics, optics, filtration and separation, biomedical engineering, and nanotechnology. Although considerable efforts have been made toward the fabrication of freestanding thin films, it is still a significant challenge to develop a simple and reliable process for producing freestanding films with ultrathin thickness, well-regulated micro/nanopatterns, robust mechanical properties, macroscopic coverage area, and multi-layered composite structures. Here, a significant advancement is reported in this regard. This study shows a new sacrificial-layer-free (SLF) lifting-off process, integrated with conventional micro-and nanolithography, enabling the release of micro-and nanopatterned photoresist (PR) films from the supporting substrate with unprecedented pattern coverage and structure characteristics. The freestanding PR film is resilient, can withstand significant bending and deformation, and is sufficiently flexible to be transferred onto substrates with 3D topography as a conformal soft stencil for further technological processing and applications. Moreover, the SLF lifting-off process provides a simple approach to prepare single-layered and multi-layered freestanding composite films. The results suggest that the novel SLF lifting-off process can significantly extend the capability of 3D micro-/nanofabrication.

Three‐Dimensional Electrodes for Oxygen Electrocatalysis

“…As is well known, self-assembly is a powerful technique, in which molecules spontaneously achieve ordered phases with well-defined nanoscale periodicity and shapes. [65,66] Yager and co-workers [67] proposed a diverse library of previously unreported 3D morphologies that are manipulated via tuning the soft self-assembling materials and block copolymer thin films (Figure 5d). In self-assembly approach, each polymer layer acts as both a structural component of the final morphology and a template for directing the order of subsequent layers.…”

Instant interfacial self-assembly for homogeneous nanoparticle monolayer enabled conformal “lift-on” thin film technology

“…The lithography-based top-down strategy features high resolution and reliability ( 2 ) but has shortcomings such as high cost, time-consuming, etc. ( 3 ). The bottom-up approach contains diverse technical routes, i.e., template-based processes, laser printing, self-assembly, chemical vapor deposition, etc.…”