Towards the Fabrication of High-Aspect-Ratio Silicon Gratings by Deep Reactive Ion Etching
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Date
2020-09
Publication Type
Journal Article
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yes
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Abstract
The key optical components of X-ray grating interferometry are gratings, whose profile requirements play the most critical role in acquiring high quality images. The difficulty of etching grating lines with high aspect ratios when the pitch is in the range of a few micrometers has greatly limited imaging applications based on X-ray grating interferometry. A high etching rate with low aspect ratio dependence is crucial for higher X-ray energy applications and good profile control by deep reactive ion etching of grating patterns. To achieve this goal, a modified Coburn–Winters model was applied in order to study the influence of key etching parameters, such as chamber pressure and etching power. The recipe for deep reactive ion etching was carefully fine-tuned based on the experimental results. Silicon gratings with an area of 70 × 70 mm2, pitch size of 1.2 and 2 μm were fabricated using the optimized process with aspect ratio α of ~67 and 77, respectively.
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published
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Volume
11 (9)
Pages / Article No.
864
Publisher
MDPI
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Subject
X-ray grating interferometry; Aspect ratio dependent etching (ARDE); X-ray energy range
Organisational unit
03817 - Stampanoni, Marco F.M. / Stampanoni, Marco F.M.
Notes
Funding
183568 - GI-BCT - Clinical Grating Interferometry Breast Computed Tomography (SNF)
727246 - Metal Assisted chemical etching of Gratings for x-ray InterferometriC systems (EC)
727246 - Metal Assisted chemical etching of Gratings for x-ray InterferometriC systems (EC)