China
Africa
Explore chapters and articles related to this topic
Interference Microscopy Techniques for Microsystem Characterization
Published in Wolfgang Osten, Optical Inspection of Microsystems, 2019
Alain Bosseboeuf, Philippe Coste, Sylvain Petitgrand
A precise control of etching processes and of stress-induced deformations of released microstructures is a major requirement for the fabrication of MEMS. Because interference microscopy is a noncontact full-field measurement technique having both high lateral and vertical resolutions and a large measurement range, it is very well suited and commonly used for this application. For etching processes, it allows a characterization of etching uniformity, aspect-ratio-dependent etching, microloading effect, and etched surface roughness, even for high-aspect-ratio patterns [29]. As an example, depth of trenches in silicon with a width down to 1 µm and a depth-to-width aspect ratio up to 10 can be measured. Interference microscopy is also well suited to the characterization of other fabrication process issues such as edge effects in electrodeposited patterns, stiction of released parts, and characterization of residues, … [29,49].
Process Simulation
Published in Louis Scheffer, Luciano Lavagno, Grant Martin, EDA for IC Implementation, Circuit Design, and Process Technology, 2018
For the purposes of this chapter it is sufficient to focus on two main etch types which are dominant in the industry, dry etching or plasma related etching (including reactive ion etching), and wet chemical etching. The two types of etch produce different shapes. Dry etching tends to be highly directional and is used to produce nearly square bottom holes, whereas wet chemical etching tends to be more isotropic producing rounded bottom holes and under etching (see Figure 24.8).
Three-Dimensional Molecular Electronics and Integrated Circuits for Signal and Information Processing Platforms
Published in Sergey Edward Lyshevski, Nano and Molecular Electronics Handbook, 2018
To date, some proof-of-concept two-terminal MEdevices have been characterized, and their I−V characteristics are measured [5,8,10,49,51,52]. To fabricate characterization test-beds, conventional microelectronic fabrication techniques, processes and materials are used. Horizontal and vertical gaps with separation between contacts in the range from ~ 1 nm to tens of nm were fabricated using photolithography, deposition, etching, and other processes. High-resolution photolithography defines planar (two-dimensional) patterns and profiles, thereby allowing one to achieve the specified patterns of insulator, metal, and other materials on the silicon wafer. Using photolithography, the mask pattern is transferred to a photoresist which is used to transfer the pattern to the substrate, as well as distinct layers on it, using sequential processes such as deposition and etching. Chemical and physical vapor deposition processes are used to deposit different insulators and conductors, while sputtering and evaporation are used to deposit Au, Pd, Ti, Cr, Al, and other metals. Wet chemical etching and dry etching are used to etch materials. Different etchants ensure desired vertical and lateral etching. Deep trenches and pits can be etched in a variety of materials, including silicon, silicon oxide, silicon nitride, etc. A combination of dry and wet etchings is integrated with materials, ensuring etching selectivity, vertical (planar) and lateral (wall) profile control, etch rate ratio control, uniformity, etc. The anisotropic etching uses etchants (potassium hydroxide, sodium hydroxide, ethylene-diamine-pyrocatecol, etc.) that etch different crystallographic directions at different etch rates. In contrast, the isotropic etching ensures the same (or close) etch rate in all directions. Different etch-stop materials are used, and these etch-stop layers can be sacrificial or structural. Shape, profile, thickness, and other features are controlled. The use of different materials, combined with etching and deposition processes, provides one with the opportunity to fabricate application-specific characterization testbeds. Molecules to be examined must be functionalized, with the metals forming robust contacts.
Hydrophilic and hydrophobic materials and their applications
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2018
Darem Ahmad, Inge van den Boogaert, Jeremey Miller, Roy Presswell, Hussam Jouhara
Chemical etching is a type of surface treatment that is commonly applied to metals. Many researchers have conducted experiments with applying hydrophobic layers onto metals, and most researchers preferred using magnesium alloy (Liu et al. 2013a; Song et al. 2013; Wang et al. 2013, 2010c; Yin et al. 2010). The etching process consists of multiple steps where (I) the sample is cleaned, often ultrasonically, and dried, (II) the material is etched in an aqueous solution, often containing copper, (III) the material is rinsed with water and often with ethanol, (IV) the material will be dried and finally (V) the material will be modified with a silica-containing solution, making the end product SHO (Liu et al. 2013a, 2013b; Song et al. 2013; Wang et al. 2013, 2010c; Yin et al. 2010).
Two-Dimensional Chemical Etching Process Simulation for Printed Circuit Heat Exchanger Channels Based on Cellular Automata Model
Published in Heat Transfer Engineering, 2018
Fei Xin, Ting Ma, Yitung Chen, Qiuwang Wang
To produce the PCHE heat transfer channels, the chemical etching technology [8, 9] is an essential process, which determines whether the high quality of PCHE can be fabricated. The chemical etching is that the substrate without photoresist on the surface is etched by the chemical reaction for certain depth, while the substrate with the photoresist on the surface is protected to obtain the needed features [10]. The main process of the chemical etching technology [11] is shown in Figure 2.