Prevention of Microroughness Generation on the Silicon Wafer Surface in Buffered Hydrogen Fluoride by a Surfactant Addition

Miyamoto, Makoto; Kita, Nozomu; Ishida, S.; Tatsuno, T.

doi:10.1149/1.2059253

Cited by 16 publications

(9 citation statements)

References 3 publications

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“…Lober et al [44] reported an attack of poly-Si in BHF and vapor HF. Corrosion of bulk silicon immersed for 24 to 48 hours in BHF can be suppressed by addition of a hydrocarbon anionic surfactant [45].…”

Section: Selectivity Against Siliconmentioning

confidence: 99%

Silicon dioxide sacrificial layer etching in surface micromachining

Bühler

Steiner

Baltes

1997

J. Micromech. Microeng.

151

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Silicon dioxide sacrificial layer etching has become a major surface micromachining method to fabricate microsensors and microactuators often made of polycrystalline silicon. An overview of the SiO 2 materials available in integrated circuit manufacturing is given, and the SiO 2 etch mechanism and sacrificial layer etch kinetics are reviewed. Selectivity issues important for the proper choice of layers and etchants are addressed discussing the chemical attack of aluminum during long sacrificial SiO 2 layer etching, as an example. Various etchants known from other studies are compared: concentrated and dilute HF, buffered HF (BHF), nitric acid (HNO 3 ) based etchants known as P-etch, R-etch, S-etch, as well as mixtures of HF and HCl, and vapor HF. 'Pad-etch', an acetic acid/ammonium fluoride/ethyleneglycole solution is shown to have an enhanced selectivity against aluminum. Some device examples such as arrays of deflectable micromirrors demonstrate the versatile application of sacrificial oxide etching in surface micromachining.

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Section: Selectivity Against Siliconmentioning

confidence: 99%

Silicon dioxide sacrificial layer etching in surface micromachining

Bühler

Steiner

Baltes

1997

J. Micromech. Microeng.

151

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“…However, attack by buffered HF on poly-silicon, leading to surface roughening, has been reported under various conditions, and has been correlated with the presence of contaminants, such as metals, as well as the deposition conditions or structure of the poly-silicon 24–27 . Microroughening of single-crystal silicon during immersion in buffered HF solutions for very long times (1–5 days) has also been described 28 . An infrared spectroscopy study of Si (111) surfaces exposed to buffered HF solutions of various p H values showed that the etch rate of these surfaces increased with OH − concentration and suggested that oxidation of the surface Si-H species is an important and probably rate limiting step for etching 29 .…”

Section: Resultsmentioning

confidence: 99%

“… 24–27 Microroughening of single-crystal silicon during immersion in buffered HF solutions for very long times (1–5 days) has also been described. 28 An infrared spectroscopy study of Si (111) surfaces exposed to buffered HF solutions of various p H values showed that the etch rate of these surfaces increased with OH − concentration and suggested that oxidation of the surface Si-H species is an important and probably rate limiting step for etching. 29 It is therefore likely that the device degradation observed here is caused by cyclic oxidation of silicon followed by etching of the resulting oxide.…”

Section: Resultsmentioning

confidence: 99%

Optimized process for fabrication of free-standing silicon nanophotonic devices

Seidler

2017

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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A detailed procedure is presented for fabrication of free-standing silicon photonic devices that accurately reproduces design dimensions while minimizing surface roughness. By reducing charging effects during inductively coupled-plasma reactive ion etching, undercutting in small, high-aspect ratio openings is reduced. Slot structures with a width as small as 40 nm and an aspect ratio of 5.5:1 can be produced with a nearly straight, vertical sidewall profile. Subsequent removal of an underlying sacrificial silicon dioxide layer by wet-etching to create free-standing devices is performed under conditions which suppress attack of the silicon. Slotted one-dimensional photonic crystal cavities are used as sensitive test structures to demonstrate that performance specifications can be reached without iteratively adapting design dimensions; optical resonance frequencies are within 1% of the simulated values and quality factors on the order of 105 are routinely attained.

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“…In HF solution, Si dissolution can occur through direct dissolution reactions: It has been reported [40] that the addition of surfactant in buffered HF etching reduces the Si dissolution because the oxidation process of Si (reactions 4 and 5) is suppressed by the adsorption of the surfactant molecules on the Si surface. Moreover, it is well known that IPA reduces the etching of SiO 2 in HF [41] because the HF dissociation decreases.…”

Section: Ipa Effect On Macetch Processmentioning

confidence: 99%

Effect of isopropanol on gold assisted chemical etching of silicon microstructures

Romano

Vila‐Comamala

Jefimovs

et al. 2017

Microelectronic Engineering

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Wet etching is an essential and complex step in semiconductor device processing. Metal-Assisted Chemical Etching (MacEtch) is fundamentally a wet but anisotropic etching method. In the MacEtch technique, there are still a number of unresolved challenges preventing the optimal fabrication of highaspect-ratio semiconductor micro-and nanostructures, such as undesired etching, uncontrolled catalyst movement, non-uniformity and micro-porosity in the metal-free areas. Here, an optimized MacEtch process using with a nanostructured Au catalyst is proposed for fabrication of Si high aspect ratio microstructures. The addition of isopropanol as surfactant in the HF-H 2 O 2 water solution improves the uniformity and the control of the H 2 gas release. An additional KOH etching removes eventually the unwanted nanowires left by the MacEtch through the nanoporous catalyst film. We demonstrate the benefits of the isopropanol addition for reducing the etching rate and the nanoporosity of etched structures with a monothonical decrease as a function of the isopropanol concentration.

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Prevention of Microroughness Generation on the Silicon Wafer Surface in Buffered Hydrogen Fluoride by a Surfactant Addition

Cited by 16 publications

References 3 publications

Silicon dioxide sacrificial layer etching in surface micromachining

Silicon dioxide sacrificial layer etching in surface micromachining

Optimized process for fabrication of free-standing silicon nanophotonic devices

Effect of isopropanol on gold assisted chemical etching of silicon microstructures

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