Ceramic micromachining

Nanotechnology involves the manipulation of matter on atomic and molecular scales. This technology combines nanosized materials in order to create entirely new products ranging from computers to micromachines and includes even the quantum level operation of materials. The structural control of materials on the nanometer scale can lead to the realization of new material characteristics that are totally different from those realized by conventional methods, and it is expected to result in technological innovations in a variety of materials including metals, semiconductors, ceramics, and organic materials. 

Excimer Laser Micromachining [132, 133] is a technique based on laser ablation. Currently, this process can routinely ablate vias as small as 6 pm in diameter in polymers, glass, ceramics and metals. The minimum size of the features that this method can produce is limited by diffraction and by heat/mass transport. Commercial instruments and services are available from a number of companies (for example, Resonetics, Itek). 

Substrates The substrates in microelectronics are mainly Si wafers. For mobile applications, silicon-on-insulator (SOI) wafers increasingly replace bulk Si wafers and for very specific high-frequency applications, III-V compound semiconductors (e.g., GaAs) are used. The majority of substrates in microfabrication are Si wafers, but metal, glass, and ceramic substrates are also common. Particularly when using glass, quartz, and ceramic wafers in CMP processes, it has to be taken into account that they are brittle and easy to break. The situation is worse when the material is also under stress induced by deposited layers. For applications where the backside of the wafer has to be structured (e.g., in bulk micromachining), double-side polished substrates are employed. 

Laser ablation is a process in which an intense btast of energy is used to remove a small amount of material fi om the surface [19]. It is the basis for excimer laser micromachining. It can be used with a variety of different materials, ranging from silicon to polymers and ceramics. Feature sizes in the low micrometer range can be realized. The advantage of laser ablation is the... 

Fabrication of 3D Metallic and 3D Ceramic Microstructures Based on Electrochemical Micromachining of A1... 

Microstructured surfaces, as well as micromachined substrates and devices discussed in Sects. II, III, and iy are suitable for a number of applications. They include reflective and absorbing surfaces, wavelength-sensitive filters, multiaperture lens arrays and Fresnel microoptics, field emitter arrays, precision apertures, or molds for microstructured surfaces of other materials. Microstructured alumina ceramics can also be used for tuned broadband infrared emitters. In addition, due to the robustness at high temperatures and well-developed and controlled porosity, the freestanding, heat-treated micromachined anodic alumina substrates can be used for the fabrication of sensors that incorporate a high temperature microheater with low power consumption. 

D. Routkevitch et al., Nano structured Ceramic Platform for Micromachined Devices and Device Arrays, U.S. Patent 6,705,152 (2004). 

The pressure ranges and environmental requirements differ from application to application therefore, various technologies coexist silicon micromachining and ceramic technologies are mostly used in the low-pressure range (1 kPa to 2 Mpa), and steel membranes are often used for higher pressures. 

Other devices such as the Cyrano Sciences, (Smiths Detection, Edgewood, MD), a handheld device using conductive polymer films deposited in an array on a ceramic substrate and the Micromachined Aconstic Chemical Sensor (Sandia National Laboratories, SNL), which is able to detect VOCs, explosives, illicit drngs, and chemical warfare agents, are also commercially available [32],... 

Besides the encouraging results, DTEGs still have great potential for further improvements. The temperature modulation frequency of 0.312 Hz is not sufficient for all applications. For fast responding devices, the temperature modulation has to be in the range of 100 Hz. Manufacturing technology needs to be adjusted in order to achieve this. Micromachined ceramics or... 

K. Kamada, M. Tokutomi, M. Inada, N. Enomoto, J. Hojo, Solid electrochemical micromachining using a tungsten microelectrode coated with polymer electrolyte, J. Ceram. Soc. Jpn. 115 (10) (2007) 672-677. 

A ceramic microreaction device with a microchannel (width 400 pm x depth 400 pm X length 40 cm) was fabricated by micromachining. From two separate inlets, the solutions of active ester in DMF and amino acid with triethylamine (added for deprotonation of amino group of amino acid) in water were loaded separately by syringe pumping (Fig. 6). The resulting solution was collected and directly analyzed by HPLC to estimate the conversion rate. Each peak obtained by HPLC was confirmed by ESI-TOFMS. In the case of reaction between... 

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