The gas film in spark assisted chemical engraving (SACE)—A key element for micro-machining applications

Wüthrich, Rolf; Hof, Lucas A.

doi:10.1016/j.ijmachtools.2005.07.029

Cited by 132 publications

(75 citation statements)

References 19 publications

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“…Indeed, as already mentioned, the main limiting factor is the stability of the gas film [7]. Newest results, which will be published elsewhere, show that it is possible by influencing the wettability of the tool-electrode (by adding surfactants to the electrolyte for example) to reduce this variance to below 5 µm [13].…”

Section: Resultsmentioning

confidence: 86%

Spark assisted chemical engraving (SACE) in microfactory

Wüthrich

Fujisaki

Couthy

et al. 2005

J. Micromech. Microeng.

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Spark assisted chemical engraving (SACE) is a method for 3D microstructuring of glass or other non-conductive materials with high aspect ratio and smooth surface quality. It is applicable for rapid prototyping of microfluidic devices, for MEMS interfacing and similar applications. Typical feature size is in the hundreds of micrometres, down to a few tens of micrometres. It is a table-top technology requiring no clean rooms and no masks and with very modest space usage. It is thus well suited for microfactories. This paper gives a basic introduction to SACE and some machining examples.

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Section: Resultsmentioning

confidence: 86%

Spark assisted chemical engraving (SACE) in microfactory

Wüthrich

Fujisaki

Couthy

et al. 2005

J. Micromech. Microeng.

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“…It may, therefore, be speculated that the critical voltage and the length of the limiting region are indicators of the gas film thickness (decreasing of these values meaning decreasing of gas film thickness). This aspect looks to be a promising method to characterize in a simple way the gas film thickness in SACE and is therefore worth investigating further [17,18].…”

Section: Discussionmentioning

confidence: 99%

Physical principles and miniaturization of spark assisted chemical engraving (SACE)

Wüthrich¹,

Hof²,

Lal³

et al. 2005

J. Micromech. Microeng.

106

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Spark assisted chemical engraving (SACE) is an unconventional micromachining technology based on electrochemical discharge phenomena for glass and various ceramics. The limits of SACE with respect to small dimensions in the particular case of glass are explored. It is found, using a specially developed set-up based on an AFM, that even using extremely sharp tool-electrodes does not allow us to produce a smaller pattern than typically 25 µm. It is concluded that the gas film thickness, in which the electrochemical discharges take place, is the main limiting factor. Further experimental investigations on its formation are investigated. By adding surfactants to the electrolyte, in order to increase the wettability of the tool-electrode and therefore to reduce the gas film thickness, it is observed experimentally that the critical voltage reduces significantly. This observation may lead to a novel method of characterizing the gas film thickness in SACE.

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“…The processing cell was mounted on an XY micro-positioning stage which is arranged underneath the tool electrode. The SACE machining was carried out using a setup similar to the one reported previously (Wüthrich and Hof 2006). A schematic of the sample with micro holes drilled at different places is shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…The workpiece of electrically nonconductive material is immersed in electrolyte. When the voltage applied across the electrodes is higher than a critical value, so that the current density on the tool-electrode is typically above 1 A/mm 2 (for 30wt% NaOH electrolyte), bubbles form vigorously on the tool-electrode and coalesce into a continuous gas film across which electrical discharges take place (Wüthrich et al 2005;Wüthrich and Hof 2006). Bringing the tool-electrode close enough to the workpiece allows machining.…”

Section: Introductionmentioning

confidence: 99%

“…Even though SACE is a low cost process and suitable for high aspect ratio machining, a serious issue which prevents its industrial adaptation is the nonrepeatability of machining rate. As the machining rate of glass is very fast, typically about 100 lm/s down to a drilling depth of around 50 lm (Wüthrich and Hof 2006), precise machining of structures with \50 lm thickness is challenging, requiring precise online measurement of machining depth and fast shutdown of the process. A rapid shutdown of the process is difficult because the machining does not stop quickly as soon as the machining voltage is switched off due to the ongoing chemical etching.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Low resistive silicon substrate as an etch-stop layer for drilling thick SiO2 by spark assisted chemical engraving (SACE)

et al. 2011

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Controlling precisely the depth in glass microdrilling by spark assisted chemical engraving (SACE) remains challenging, particularly for low depths. The possibility of using an electrically conductive material as an etch-stop layer for SACE gravity-feed drilling is investigated in this paper. Micromachining with constant DC and pulsed DC of 30-35 lm thick SiO 2 deposited on low resistive silicon substrate demonstrated the etch-stop function of the conductive silicon. Measurements of etch rates and hole profiles along with scanning electron microscope imaging revealed the mechanism underlying the etch-stop process. Low resistive silicon is demonstrated to be a good etch-stop layer for SACE gravity-feed drilling. Demonstration of machining of SiO 2 layer on silicon as a substrate and an etch-stop layer opens up new possibilities to adapt SACE for developing devices on silicon platform.

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The gas film in spark assisted chemical engraving (SACE)—A key element for micro-machining applications

Cited by 132 publications

References 19 publications

Spark assisted chemical engraving (SACE) in microfactory

Spark assisted chemical engraving (SACE) in microfactory

Physical principles and miniaturization of spark assisted chemical engraving (SACE)

Low resistive silicon substrate as an etch-stop layer for drilling thick SiO2 by spark assisted chemical engraving (SACE)

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