Anisotropic wetting

The membranes of the microhotplates were released by anisotropic, wet-chemical etching in KOH. In order to fabricate defined Si-islands that serve as heat spreaders of the microhotplate, an electrochemical etch stop (ECE) technique using a 4-electrode configuration was applied [109]. ECE on fully processed CMOS wafers requires, that aU reticles on the wafers are electrically interconnected to provide distributed biasing to the n-well regions and the substrate from two contact pads [1 lOj. The formation of the contact pads and the reticle interconnection requires a special photolithographic process flow in the CMOS process, but no additional non-standard processes. 

The partial wetting of a melt on a low-index plane of its solid has already been predicted - and observed on Cd", Ga , Ge, NaCT and KCl . However, as mentioned earlier, indications of anisotropic wetting have been limited to Ge and icel In the case of Pb, the wetting angle is shown to increase as the surface free energy, or the atomic density of the surface plane, decreases. Germanium was quoted as having a similar behaviouf. 

W.C. Cheng, D. Chatain and P. Wynblatt, Observations of Anisotropic Wetting in Solid-Liquid Pb-Ga... 

Figure 16. Schematic diagram illustrating phase-separated columnar-structure-induced anisotropic wet chemical etching. (Reproduced with...

Tanaka et al. [73] developed another MEMS system for the catalytic combustion of butane. It is composed of a combustion chamber 8 mm wide, 14 mm long and 150 pm deep which was prepared by anisotropic wet etching of a silicon substrate. The substrate was then covered with Pyrex glass applying anodic bonding. Combustion was performed on a platinum/titania catalyst... 

HF-HNOj Unspecified etch rate Anisotropic Wet Etch i... 

What are the differences between isotropic and anisotropic wet etch of silicon (2 marks)... 

Figure 3.44. Schematic representation of anisotropic wet chemical etching of GcxSei x- Reproduced with permission from reference 151. Copyright 1985 Society of Plastics Engineers.)...

Adhesives for integrated circuits, requirements, 14 AgCl-As2S3, 172 Ag2Se-GejSei., resists development of latent image, 174 anisotropic wet chemical etching, 177/ chemical basis, 174... 

Micro-reaction chambers for the thermal cycling of DNA amphfication by the polymerase chain reaction (PCR) in silicon by bulk machining using anisotropic wet etching have been fabricated by Moore and co-workers [40]. The rapid temperature cycling and the small size of the chambers may be combined with an appropriate transducer in a miniaturized analytical system. 

Kudelka, S., Michaelis, A. and Tobben, D. (2002) Bottle Shaped Trench Formation by Anisotropic Wet Etch, US Patent 98-0324. 

D lithography was performed by using the contact mask aligner (Karl Suss, MA6/BA6). The channel formed by anisotropic wet etching was chosen for the channel fabrication of the pDMFC because UV light can be irradiated to the sidewall. The photograph of the fabricated pDMFC is shown in Fig. 5.5. The performance of... 

Neuhaus S, Spencer ND, Padeste C. Anisotropic wetting of microstructured surfaces as a function of surface chemistry. ACS Appl Mater Interfaces 2012 4(1) 123—30. 

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