Unmasking the Resolution–Throughput Tradespace of Focused‐Ion‐Beam Machining

Abstract

Focused‐ion‐beam machining is a powerful process to fabricate complex nanostructures, often through a sacrificial mask that enables milling beyond the resolution limit of the ion beam. However, current understanding of this super‐resolution effect is empirical in the spatial domain and nonexistent in the temporal domain. This article reports the primary study of this fundamental tradespace of resolution and throughput. Chromia functions well as a masking material due to its smooth, uniform, and amorphous structure. An efficient method of in‐line metrology enables characterization of ion‐beam focus by scanning electron microscopy. Fabrication and characterization of complex test structures through chromia and into silica probe the response of the bilayer to a focused beam of gallium cations, demonstrating super‐resolution factors of up to 6 ± 2 and improvements to volume throughput of at least factors of 42 ± 2, with uncertainties denoting 95% coverage intervals. Tractable theory models the essential aspects of the super‐resolution effect for various nanostructures. Application of the new tradespace increases the volume throughput of machining Fresnel lenses by a factor of 75, enabling the introduction of projection standards for optical microscopy. These results enable paradigm shifts of sacrificial masking from empirical to engineering design and from prototyping to manufacturing.

Nano Hotplate Fabrication for Metal Oxide-Based Gas Sensors by Combining Electron Beam and Focused Ion Beam Lithography

“…The AFM images in Figure 7a prove that the single-loop patterning process results in a deeper milling but a higher re-sputtering rate and consequently higher roughness. On the contrary, Figure 7b proves that the multi-loop milling strategy leads to a clean removal of the Pt layer, limiting the chances of redeposited Pt atoms on the milled area [28,38,39]. Figure 8 highlights the exact milling depths and roughness of the area obtained from AFM data.…”

Level set simulation of focused ion beam sputtering of a multilayer substrate

“…Examples that rely on ion milling include patterning of magnetic multilayers [ 11 ], fabrication of optical metamaterials [ 12 ], and modification of semiconductor heterostructures [ 13 ]. Metal and dielectric layers can be used as hard masks for achieving high resolution and throughput of the FIB nanofabrication process [ 14 ]. Modification of integrated circuits [ 15 ] is an industrially relevant application of multilayer structure processing.…”

Моделирование Распыления Многослойных Подложек Фокусированным Ионным Пучком

“…Распыление (травление) многослойных структур методом ФИП необходимо для решения ряда задач. Так, слои металлов и диэлектриков могут использоваться в качестве твердых масок, обеспечивающих высокое разрешение и производительность процесса формирования наноструктур с помощью ФИП [1]. Практически значимым примером воздействия ФИП на многослойные структуры является, в частности, модификация интегральных микросхем [2] и волноводов полупроводниковых лазеров [3].…”