Reactive etching by ClF 3 –Ar neutral cluster beam with scanning

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• The reactive gas cluster injection process is an etching method that uses a neutral cluster beam without plasma. This process can avoid damage caused by energetic ion irradiation and vacuum UV light from plasma. The characteristics of etching by ClF3–Ar gas cluster injection were investigated at various target distances, pattern widths, and sample temperatures. As a result, the relationship between the etching conditions and the aspect ratio was clarified, and an equation that can predict the maximum limit of aspect ratio was derived from the ClF3 flux and pattern widths. Then high aspect etching with an aspect ratio exceeding 20 is realized. And also, 3D lever structure of 6 layers can be fabricated by double-angled etching with neutral cluster injection at the condition for high aspect etching.

Section: Methodsmentioning

confidence: 99%

High aspect (>20) etching with reactive gas cluster injection

SEKI¹,

Yamamoto²,

Koike³

et al. 2022

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“…31) As the vapor pressure of pure ClF 3 is less than 0.2 MPa at 300 K, a ClF 3 -Ar gas mixture was used as the source gas. 30) The source gas was a mixture of ClF 3 (99.995%) and Ar (99.999%) with a volume ratio of 9% ClF 3 that was held at room temperature. The pressure (P 0 ) range at which the ClF 3 -Ar gas mixture was fed into the conical nozzle was 0.5-0.9 MPa and the nozzle diameter was 0.05-0.10 mm.…”

Section: Methodsmentioning

confidence: 99%

“…29) To increase the Si processing area, a reactive gas cluster injection system with a scanning function was developed. 30) When etching was performed with scanning, the aspect ratio decreased because of the etching of the side walls by the gas retained in the trench. The aspect ratio was improved by reducing the source gas pressure, increasing the target distance, and mixing He in the source gas.…”

Section: Introductionmentioning

confidence: 99%

Angled etching of Si by ClF₃–Ar gas cluster injection

Seki

Yamamoto

Kozawa

et al. 2017

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Reactive gas cluster injection is an etching method that uses a neutral cluster beam without ions. This process can avoid damage caused by energetic ion irradiation and vacuum UV light from plasma. ClF 3 -Ar gas cluster injection was performed using a nozzle placed at various angles in the range of 0-78°from the normal to the sample. The Si substrate was anisotropically etched in the direction of the cluster beam, although the incident angle of the cluster beam was oblique. Oblique holes of 100 nm diameter and oblique square pillars of 3 µm width were fabricated with a high aspect ratio by angled cluster injection. It is expected that this process will create unprecedented structures for use in micro-electromechanical systems (MEMSs) or photonic crystals.

“…[74][75][76][77][78][79][80][81][82][83] Recently, angled features were fabricated by a ClF 3 -Ar gas cluster injection system. 84,85) Also, transport and redeposition of neutrals and by-products should be taken into consideration as causes of distortion. Nishikawa et al reported in situ monitoring of etchant and product species in plasma etching using Fourier transform infrared spectroscopy (FT-IR).…”

Section: Har Feature Profile Control: From Two Dimensions To Three Di...mentioning

confidence: 99%

Progress in nanoscale dry processes for fabrication of high-aspect-ratio features: How can we control critical dimension uniformity at the bottom?

Ishikawa

Karahashi

Ishijima

et al. 2018

In this review, we discuss the progress of emerging dry processes for nanoscale fabrication of high-aspect-ratio features, including emerging design technology for manufacturability. Experts in the fields of plasma processing have contributed to addressing the increasingly challenging demands of nanoscale deposition and etching technologies for high-aspect-ratio features. The discussion of our atomic-scale understanding of physicochemical reactions involving ion bombardment and neutral transport presents the major challenges shared across the plasma science and technology community. Focus is placed on advances in fabrication technology that control surface reactions on three-dimensional features, as well as state-of-the-art techniques used in semiconductor manufacturing with a brief summary of future challenges.