Near-field infrared nanoscopic study of EUV- and e-beam-exposed hydrogen silsesquioxane photoresist

Abstract

This article presents a technique of scattering-type scanning near-field optical microscopy (s-SNOM) based on scanning probe microscopy as a nanoscale-resolution chemical visualization technique of the structural changes in photoresist thin films. Chemical investigations were conducted in the nanometer regime by highly concentrated near-field infrared on the sharp apex of the metal-coated atomic force microscopy (AFM) tip. When s-SNOM was applied along with Fourier transform infrared spectroscopy to characterize the extreme UV- and electron-beam (e-beam)-exposed hydrogen silsesquioxane films, line and space patterns of half-pitch 100, 200, 300, and 500 nm could be successfully visualized prior to pattern development in the chemical solutions. The linewidth and line edge roughness values of the exposed domains obtained by s-SNOM were comparable to those extracted from the AFM and scanning electron microscopy images after development. The chemical analysis capabilities provided by s-SNOM provide new analytical opportunities that are not possible with traditional e-beam-based photoresist measurement, thus allowing information to be obtained without interference from non-photoreaction processes such as wet development.

Progress in Polyhedral Oligomeric Silsesquioxane (POSS) Photoresists: A Comprehensive Review across Lithographic Systems

“…With the rapid advancement of integrated circuits, there is a continual reduction in the characteristic size of semiconductor chips. As depicted in Figure 1 , the characteristic size has been reduced from 436 nm (G-line) to 365 nm (UV), to 248 nm (deep ultraviolet (DUV) KrF, 193 nm (ArF excimer lasers), and to even smaller sizes of 13.5 nm and 3–5 nm (extreme ultraviolet (EUV) [ 1 ]. The photoresist, a pivotal material affecting the characteristic size of chips, is subject to increasingly stringent demands regarding its sensitivity, resolution, and line edge roughness, among other properties [ 2 , 3 ].…”

Si-Containing Reverse-Gradient Block Copolymer for Inorganic Pattern Amplification in EUV Lithography

“…This innovation facilitates the production of high-resolution patterns beyond the capabilities of other scalable and reliable patterning technologies, positioning EUVL at the forefront of next-generation semiconductor manufacturing. − However, the practical realization of high-NA (numerical aperture) EUVL currently faces a number of technical challenges. One of the most critical challenges is the requirement for a thin photoresist (PR) layer, which leads to low aspect ratios (AR) in the PR etch-mask and, consequently, poor etching performance due to the insufficient endurance of the resist. − Recent studies have focused on mitigating the limitations in pattern resolution and AR encountered in EUVL. These efforts include the development of inorganic-based PRs and the integration of robust hard-mask underlayers to enhance pattern fidelity. − Despite these advancements, the patterns realized under EUV exposure have achieved an AR of only about 2.1, which is suboptimal for reliable pattern transfer during subsequent etching processes …”