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Reduced Etch Lag and High Aspect Ratios by Deep Reactive Ion Etching (DRIE)

Gerlt, Michael S LU orcid ; Läubli, Nino F ; Manser, Michel ; Nelson, Bradley J and Dual, Jürg (2021) In Micromachines 12(5).
Abstract

Deep reactive ion etching (DRIE) with the Bosch process is one of the key procedures used to manufacture micron-sized structures for MEMS and microfluidic applications in silicon and, hence, of increasing importance for miniaturisation in biomedical research. While guaranteeing high aspect ratio structures and providing high design flexibility, the etching procedure suffers from reactive ion etching lag and often relies on complex oxide masks to enable deep etching. The reactive ion etching lag, leading to reduced etch depths for features exceeding an aspect ratio of 1:1, typically causes a height difference of above 10% for structures with aspect ratios ranging from 2.5:1 to 10:1, and, therefore, can significantly influence subsequent... (More)

Deep reactive ion etching (DRIE) with the Bosch process is one of the key procedures used to manufacture micron-sized structures for MEMS and microfluidic applications in silicon and, hence, of increasing importance for miniaturisation in biomedical research. While guaranteeing high aspect ratio structures and providing high design flexibility, the etching procedure suffers from reactive ion etching lag and often relies on complex oxide masks to enable deep etching. The reactive ion etching lag, leading to reduced etch depths for features exceeding an aspect ratio of 1:1, typically causes a height difference of above 10% for structures with aspect ratios ranging from 2.5:1 to 10:1, and, therefore, can significantly influence subsequent device functionality. In this work, we introduce an optimised two-step Bosch process that reduces the etch lag to below 1.5%. Furthermore, we demonstrate an improved three-step Bosch process, allowing the fabrication of structures with 6 μm width at depths up to 180 μm while maintaining their stability.

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Please use this url to cite or link to this publication:
author
; ; ; and
publishing date
type
Contribution to journal
publication status
published
subject
in
Micromachines
volume
12
issue
5
article number
542
publisher
MDPI AG
external identifiers
  • pmid:34068670
  • scopus:85106710954
ISSN
2072-666X
DOI
10.3390/mi12050542
language
English
LU publication?
no
id
5bd48460-5ebd-4bf7-ab82-ff4b5e9aeb8c
date added to LUP
2023-04-12 09:17:18
date last changed
2024-06-15 01:49:51
@article{5bd48460-5ebd-4bf7-ab82-ff4b5e9aeb8c,
  abstract     = {{<p>Deep reactive ion etching (DRIE) with the Bosch process is one of the key procedures used to manufacture micron-sized structures for MEMS and microfluidic applications in silicon and, hence, of increasing importance for miniaturisation in biomedical research. While guaranteeing high aspect ratio structures and providing high design flexibility, the etching procedure suffers from reactive ion etching lag and often relies on complex oxide masks to enable deep etching. The reactive ion etching lag, leading to reduced etch depths for features exceeding an aspect ratio of 1:1, typically causes a height difference of above 10% for structures with aspect ratios ranging from 2.5:1 to 10:1, and, therefore, can significantly influence subsequent device functionality. In this work, we introduce an optimised two-step Bosch process that reduces the etch lag to below 1.5%. Furthermore, we demonstrate an improved three-step Bosch process, allowing the fabrication of structures with 6&amp;nbsp;μm width at depths up to 180&amp;nbsp;μm while maintaining their stability.</p>}},
  author       = {{Gerlt, Michael S and Läubli, Nino F and Manser, Michel and Nelson, Bradley J and Dual, Jürg}},
  issn         = {{2072-666X}},
  language     = {{eng}},
  month        = {{05}},
  number       = {{5}},
  publisher    = {{MDPI AG}},
  series       = {{Micromachines}},
  title        = {{Reduced Etch Lag and High Aspect Ratios by Deep Reactive Ion Etching (DRIE)}},
  url          = {{http://dx.doi.org/10.3390/mi12050542}},
  doi          = {{10.3390/mi12050542}},
  volume       = {{12}},
  year         = {{2021}},
}