MEMS fabrication process

Besides, high-performance polymer electrets, sueh as Parylene HT and certain types of CYTOP, were introduced to the family of electret materials. They exhibit not only excellent electret properties (high surfaee charge density with exceptional long-term and thermal stability) but also good compatibility with MEMS fabrication process. 

Typically each new MEMS device requires the development of a new MEMS fabrication process, so controlling the thin-film properties in one process does not necessarily help with control of the thin-film properties... 

MEMS (microelectromechanical systems) are systems with small device sizes of 1-100 pm. They are typically driven by electrical signals. To fabricate such systems materials like semiconductors, metals, and polymers are commonly used. MEMS technology fabrication is very cost-efficient. The structures are transferred by processes, which are applied to many systems on one substrate or even many of them simultaneously. The most important fabrication processes are physical vapor deposition (PVD), chemical vapor deposition (CVD), lithography, wet chemical etching, and dry etching. Typical examples for MEMS are pressure, acceleration, and gyro sensors [28,29], DLPs [30], ink jets [31], compasses [32], and also (bio)medical devices. 

The fabrication of the PIMMS-chips is based only on MEMS standard processes. 

Moy AL, Hetherington DL. CMP processing issues for MEMS fabrication technology. Proceedings of the 11th CMP-MIC 2006. p335-342. 

Oxide CMP for MEMS fabrication represents the most recent oxide CMP application. It deals with very thick oxide films and large step heights. Typically, PMD or ILD CMP would remove 0.1 1 pm of oxide. In MEMS applications the amount of oxide to be removed is on the order of 1-10 pm. The step height to be eliminated is in the same range and the structure size ranges from a micrometers few to millimeters. Most MEMS CMPs use processes similar to ILD CMP. As these tools and consumables were originally developed for conventional CMP, it usually takes much longer time to process MEMS wafers (see Chapter for details). 

The processability of certain CEPs has been utilized in the construction of microsystems, particularly miniature sensor systems. For example, simply dip-coating connecting platinum wires with a polyaniline formulation produces a useful humidity sensor.133 CEPs can also be screen-printed or ink-jet-printed to produce the complex shapes needed for various devices. Electrodeposition of CEPs is also a popular processing method, and this technique is compatible with conventional MEMS fabrication, where lithography and etching can be used to prepattern metal electrodes. Subsequent deposition of CEP by electrochemical polymerization produces the CEP microdevice.129... 

C. Stokes and P. Palmer, 3D micro-fabrication processes A review. Proceedings of the Seminar on MEMS Sensors and Actuators, Institution of Engineering and Technology, London, U.K., pp. 289—298,... 

The anisotropic wet etching of silicon is a unique fabrication process in the MEMS field. The need to develop new processes to fabricate functional 3D microstructures in various materials is urgent for progress in microfluidic systems, microsensors, micro-actuators, and microinstrumentation. At present, to integrate surface micromachined devices and standard IC devices with bulk micromachined structures to demonstrate a new functional MEMS application is still a challenge for researchers who work in this field. The cooperation of multidisciplinary researchers will be required to develop miniature systems with the most appropriate building philosophy and the best operation performance. 

Auciello O, et al. Materials science and fabrication processes for a new MEMS technology based on ultrananocrystaUine diamond thin films. J Phys Condens Matter 2004. 

The fluid control MEMS is composed of a microdiaphragm and micro-channel. Figure 5.31 shows the fabrication process of a multilayer diaphragm structure. 

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