Applications Anodic bonding

The wafers containing the etched trenches are anodically bonded to Pyrex glass to form closed channels. The bond strength thus formed is strong enough to withstand pressures up to 250 bar. At that point a breakdown even takes place in the mono crystalline silicon and not at the bonded interface. Clearly, the indicated structures are useful for HPLC applications. 

An interesting device for application in distillation was fabricated by milling on a silicon substrate [34]. The chamber was closed by a glass plate using anodic bonding. Methanol/water mixtures were used as a model system. In this device wall effects achieve separation of gas and liquid. The liquid is collected near the wall whereas the gas is withdrawn at a central cavity. Liquid moves to the wall by surface forces and gravity. The rectangular separation chamber was equipped with a liquid inlet, and a liquid outlet was located in the lower part of the device whereas the gas phase leaves at the top. 

Labossiere, P.E.W., Dunn, M.L., and Cunningham, S.J., Application of bimaterial interface comer failure mechanics to silicon/glass anodic bonds, Jourruil of the Mechanics and Physics of Solids 2002, 50,405-433. 

Silicon material is normally of standard wafer sizes and thicknesses. As the anode part of the bonding pair, the silicon should be low in resistivity. However, some applications require an insulating layer to prevent electrical leakage in silicon. In this case, a thin layer of silicon dioxide or silicon nitride should be deposited on the silicon surface. The insulating layer does not prevent anodic bonding of silicon with glass. However, a thicker insulating layer... 

Anodic bonding is relatively simple in principle and has been well developed over the last few decades. Research in this area has been very much focused on solving practical and application-specific issues. One of the practi-... 

Henkel et al. [214] demonstrated the application of wet chemical etching of glass (BOROFLOAT 33, Schott Jena, thickness 0.7 mm) to produce a chip module for the manipulation of fluids. The used etch mask was a Ni/Cr layer of 150 nm thickness. The complete chip consists of two sheets with half channels joined by anodic bonding. 

Surface analysis has made enormous contributions to the field of adhesion science. It enabled investigators to probe fundamental aspects of adhesion such as the composition of anodic oxides on metals, the surface composition of polymers that have been pretreated by etching, the nature of reactions occurring at the interface between a primer and a substrate or between a primer and an adhesive, and the orientation of molecules adsorbed onto substrates. Surface analysis has also enabled adhesion scientists to determine the mechanisms responsible for failure of adhesive bonds, especially after exposure to aggressive environments. The objective of this chapter is to review the principals of surface analysis techniques including attenuated total reflection (ATR) and reflection-absorption (RAIR) infrared spectroscopy. X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and secondary ion mass spectrometry (SIMS) and to present examples of the application of each technique to important problems in adhesion science. 

In primer formulations for adhesive bonding of metals, the coupling agents that are most frequently used are those based on epoxy and amine functionalities. Aqueous solutions of aminosilanes have been successfully used for obtaining stable adhesive bonds between epoxy and steel [10] and epoxy and titanium [11,12], while epoxy functional silanes are preferable for applications involving aluminum substrates [13,14], A simple solution of % epoxy functional silane in water is currently used for field repairs of military aircraft [15] where phosphoric acid anodization would be extremely difficult to carry out, and performance is deemed quite acceptable. 

Anodic alumina oxides find steadily growing application in various spheres of technology. Traditionally, they are most popular in civil industrial engineering for producing protective and decorative surface finish in panels and different objects. These applications are well reviewed in the literature.321 Anodic alumina is also widely used in the aircraft and aerospace industry for adhesive bonding of aluminum structures,322-324 composite materials, etc. 

Studies on the electrochemical oxidation of silyl-substituted ethers have uncovered a rich variety of synthetic application in recent years. Since acetals, the products of the anodic oxidation in the presence of alcohols, are readily hydrolyzed to carbonyl compounds, silyl-substituted ethers can be utilized as efficient precursors of carbonyl compounds. If we consider the synthetic application of the electrooxidation of silyl-substituted ethers, the first question which must be solved is how we synthesize ethers having a silyl group at the carbon adjacent to the oxygen. We can consider either the formation of the C-C bond (Scheme 15a) or the formation of the C-O bond (Scheme 15b). The formation of the C Si bond is also effective, but this method does not seem to be useful from a view point of organic synthesis because the required starting materials are carbonyl compounds. 

CH2CI2, sulfolane, THF) in the presence of alkenes, whose oxidation potential is lower than that of the disulfide, results in the addition of the MeS group on the double bond. Since then, the anodic sulfeanylation of multiple bonds received many synthetic applications. 

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