The effect of isopropyl alcohol concentration on the etching process of Si-substrates in KOH solutions

Zubel, Irena; Rola, Krzysztof; Kramkowska, M.

doi:10.1016/j.sna.2011.09.005

Cited by 71 publications

(46 citation statements)

References 22 publications

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“…Similar anisotropy of the etch rate reduction was also observed in KOH solutions saturated with alcohols [11], [13]- [16] and in TMAH solutions containing nonionic surfactants (including Triton) [8], [24], [26], [28], [34]. The existence of the thicker layer of surfactant on the (110) surface has been confirmed experimentally [29], [34].…”

Section: Discussionsupporting

confidence: 71%

“…The (110) surfaces exhibit the typical zigzag pattern [37], [40], whereas the (100) surfaces are covered with hillocks bounded by {111} vicinal planes, which differ a little from more pyramidal hillocks appearing in the KOH solutions with alcohols [12], [13]- [16]. In the pure KOH solutions, the (100) surface roughness is decreased when the hydroxide concentration is increased [12], [37].…”

Section: Discussionmentioning

confidence: 99%

“…Saturation of the solution with butyl alcohols not only yields striped {110} planes, but also roughens the (100) surface [13]- [15]. Although the smoothness of (110) surface is improved at low alcohols concentrations (below the saturation level), the (100) surface is covered with pyramidal hillocks [16], [17]. Furthermore, controlling the composition of the non-saturated solution is difficult due to the evaporation of alcohol at elevated temperatures during the etching process.…”

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confidence: 99%

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Triton Surfactant as an Additive to KOH Silicon Etchant

Rola

Zubel

2013

J. Microelectromech. Syst.

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Anisotropic etching of Si (100) and (110) planes in alkaline solutions containing the nonionic surfactant is studied in this paper. Triton X-100 surfactant, normally used for the modification of TMAH (tetramethylammonium hydroxide) etchant, is added to KOH (potassium hydroxide) solution. As a result, the (100) and (110) etch rates are significantly reduced and the etch rate ratio R(100)/R(110) >1 is obtained. The influence of KOH concentration (at 10 and 100 ppm (v/v) of the surfactant) on the etching process is also investigated. Low roughness of (110) surface is achieved in the 2 M KOH solution containing Triton. The smooth {110} sidewall planes inclined at 45°toward the (100) substrate are fabricated by etching in the KOH + Triton solution. The 45°{110} sidewalls are potentially attractive as MEMS micromirrors for optical beam reflection at an angle of 90°. The low etch rate of (100) plane is kind of a disadvantage of the fabrication method, but it can be fairly overcome by elevating the process temperature and stirring the etching solution.[ 2012-0371]Index Terms-Anisotropic etching, potassium hydroxide (KOH), silicon, surfactant, Triton X-100.

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Section: Discussionsupporting

confidence: 71%

Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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Triton Surfactant as an Additive to KOH Silicon Etchant

Rola

Zubel

2013

J. Microelectromech. Syst.

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“…Addition of tensioactive compounds to these solutions makes this process much more complex. In the literature there are some considerations concerning the behavior of Triton in TMAH solutions [12][13][14] and the performance of alcohols with one hydroxyl group during etching in KOH 15 . A method of an assessment of the effect of tensioactive compounds on the properties of etching solutions is a measurement of their surface tension.…”

Section: Introductionmentioning

confidence: 99%

Behavior of tensioactive compounds in the solutions for silicon anisotropic etching

2013

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In this work, results of measurements of surface tension of KOH and TMAH solutions containing alcohol additives were used to assess the behavior of the alcohols during silicon anisotropic etching. Surface tension of KOH and TMAH solutions containing additives of alcohols with one or more hydroxyl groups as well as etching rates and surface roughness of Si(100) and Si(110) surfaces etched in these solutions were analyzed. An improvement in roughness of both the planes was observed after addition of the alcohols to the KOH and TMAH solutions, however reduction of etching rates of Si(110) planes occurred only in KOH solutions. Based on surface tension measurements, it was stated that reduction of etching rates results from selective adsorption of the surface active compound on Si surfaces, which is possible due to adsorption layer formed on the solution surface of KOH etchant. The adsorption layer does not appear in TMAH + alcohols solutions, which accounts for a different behavior of TMAH-based etchants.

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“…KOH/2-propanol etching was not applied to CMOS chips and Si (100) wafers because these smaller surfaces could be efficiently cleaned and activated by UV irradiation as discussed in II.2.1 and described in V.3.1.1. However, if no UV equipment is available, homogenous etching of Si(100) wafers should be possible with 3 M KOH + 2 M 2-propanol or 5 M KOH + 1 M 2-propanol in water as reported by ZUBEL et al [126][127] Throughout this work, all polymeric films synthesized on CMOS chips or Si(100) wafers were stable independent of their subsequent use. The polymer coatings typically reached a thickness of 50 nm and did not exceed a thickness of 80 nm.…”

Section: Iii11 Improved Cleaning and Activationmentioning

confidence: 93%

Purification of Peptides in High-Complexity Arrays

Schirwitz

2013

Springer Theses

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Compared to the human genome, which is formed by approximately 25,000 genes, the human proteome comprises over a million functional proteins and thus represents a much higher diversity. Although genetic research provides valuable information on the proteins which can be translated, a great task in the future will be the exploration of the entire protein interaction network. Understanding protein interactions will greatly help scientists to identify the mechanisms behind fatal diseases such as cancer, AIDS, and tuberculosis and, hopefully, provide new

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The effect of isopropyl alcohol concentration on the etching process of Si-substrates in KOH solutions

Cited by 71 publications

References 22 publications

Triton Surfactant as an Additive to KOH Silicon Etchant

Triton Surfactant as an Additive to KOH Silicon Etchant

Behavior of tensioactive compounds in the solutions for silicon anisotropic etching

Purification of Peptides in High-Complexity Arrays

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