Micro Electro-Mechanical Systems
Micro Electro-Mechanical Systems (MEMS) is the integration of mechanical elements, sensors, actuators and electronics on a common silicon substrate using microfabrication techniques. MEMS are a hot area of research because they integrate sensing, analyzing and responding on the same silicon substrate hence promising realization of complete systems-on-a-chip. As MEMS are manufactured using batch fabrication techniques similar to IC technology, MEMS are expected to deliver high functionality at low prices.
Current systems are limited by the capability of sensors and actuators, as these are bulkier and less reliable than the microelectronic circuit. In a MEM system the sensors act as the ‘eyes’ and gather data about the environment. The microelectronic circuit, which is the ‘brain’, processes the data and accordingly controls the mechanical systems, the ‘arms’ of the MEMS, to modify the environment suitably. The electronics on the MEMS are manufactured using IC techniques while micro machining techniques are used to produce the mechanical and electromechanical parts.
MEMS Fabrication:
There are number of methods to fabricate MEMS like silicon surface micromachining, silicon bulk machining, electro discharge machining, LIGA (in German, Lithographie, Galvanoformung(Electro Plating), Abformung(Injection Moulding)) .Only silicon surface micromachining is discussed here.
Silicon Surface Micromachining
Silicon surface micromachining uses the same equipment and processes as the electronics semiconductor industry. There are three basic building blocks in this technology, which are the ability to deposit thin films of material on a substrate, to apply a patterned mask on top of the films by photolithographic imaging, and to etch the films selectively to the mask. A MEMS process is usually a structured sequence of these operations to form actual devices.
1. Deposition Processes: One of the basic building blocks in MEMS processing is the ability to deposit thin films of material. This is achieved either through the processes like PVD or CVD.
2. Lithography: Lithography in the MEMS context is typically the transfer of a pattern to a photosensitive material by selective exposure to a radiation source such as light. In lithography for micromachining, the photosensitive material used is typically a photoresist. When resist is exposed to a radiation source of a specific a wavelength, the chemical resistance of the resist to developer solution changes.
3. Etching: If the resist is placed in a developer solution after selective exposure to a light source, it will etch away one of the two regions (exposed or unexposed). Then another layer of material is deposited and the first layer selectively etched away as shown in the figure resulting in the required MEMS.
Microelectromechanical Systems (MEMS) are systems that are designed on a micro metre scale and have become more popular as the demand for devices to get smaller has increased. The main uses of these systems are for sensors, such as accelerometers and gyroscopes and other such devices like microscopy and inkjet nozzles for example. There are many materials that can be used for MEMS as the cost of the material is almost eradicated due to the micro size of the systems being produced. This brings materials such as gold, platinum and diamond can be used, as these materials have some properties which are very desirable for a MEM systems. The most common material that is currently used in MEMS is silicon and silicon based compounds as they possess many good properties for MEMS production. Most of the materials chosen for MEMS are semiconductor materials Figure 1 shows the properties of commonly used materials.
Everyone has violated either moral or religious law at least once in his or her entire lifetime. On the outside, they might be "looking pure as new-fallen snow; while their hearts are all speckled and spotted with iniquity of which they cannot rid themselves."(p.116) Some walk secretly with this heavy sin in their heart, while others get shamed in public because their sin is displayed openly. Since these sins are all different, the consequences and the significance may also vary in importance. In The Scarlet Letter by Nathaniel Hawthorne, Hester Prynne, Arthur Dimmesdale and Roger Chillingworth sins and all of the wrongdoings vary in significance.
This tool has a thin metal sheet or ribbon attached to the handle. The ribbon carves into the material.
3D printing has the potential to revolutionize the way we make almost everything. 3D printing was invented in the mid 1980s and was initially known as additive manufacturing. It consists of the fabrication of products through the use of printers which either employ lasers to burn materials (sintering) or place layer upon layer of material (known as stereolithography), eventually resulting in a finished item. Unlike the traditional manufacturing process, which involves milling, drilling, grinding or forging molded items to make the final product, 3D printing “forms” the product layer by layer. There are many different technological variants but almost every existing, 3D printing machine functions in a similar way: a 3D computer-aided engineering (CAD) file is sliced into a series of 2D planar sections and these are deposited by the printer, one above the other, to construct the part.
A change in resistance is observed by changing the current (or voltage), keeping the voltage (or current) constant. Each taxel contains a pressure sensitive crystal in the form of conductive rubber, elastomer or conductive ink. Measuring change in resistance requires a simple circuitry and hence, these are simpler to manufacture. Applied for touch sensing in anthropomorphic hands (Weiss & Worn 2004), piezoresistive tactile sensing, has become popular among the MEMS and silicon type tactile sensors (Woffenbuttel & Regtien 1991; Beebe, Hsieh et al.
Santa Clara Valley, California, better known as Silicon Valley, is the birthplace and reigning capital of the largest and fastest growing manufacturing industry in the world, microelectronics (Hossfeld 405). Microelectronics is defined as a branch of electronics that deals with the miniaturization of electric circuits and components. This involves computers, processor, cell phones, and many other electronic devices. Cell phones are becoming a part of the microelec...
Describe the design on the machine and how their component parts work to produce an image.
Rapid prototyping is the realization of an idea into a physical object in order to provide a representative of a finished product using rapid prototyping technologies to allow for appraisal and design modifications. The First rapid prototyping machine was first made available to markets in late 1987 meaning it is a relatively recent development. Rapid prototyping began as an expensive tool for manufacturing a physical model for design engineers to use to visualize their component designs. However in recent years the technology has advance so much that it is becoming cheaper to produce a component. (1)
Zatzick, Moliterno, and Fang (2012) write that Total Quality Management “TQM primarily focuses on increasing inefficiencies and improving processes, particularly when implemented in manufacturing organizations” (p.1322). Deming (1988) writes that American companies do not work steadily towards process improvement. He feels that management should be consistent with its efforts to improve upon the quality of its products. Beer (2003) views TQM as an ongoing process in order to ensure product excellence. TQM has the ability to change the companies’ culture and work processes. Quality management is a long term process. These changes usually require new initiatives. Deming (1998) explains how the Japanese are at an advantage because they are not beholden to stakeholders. Japanese companies are able to concentrate on their employees. This type of environment encourages trust between workers and management. Beer (2003) feels that TQM involves “multiple stakeholder philosophy that equally values community, customers, and employees (p.624). Team work and collaboration are a big part of the TQM philosophy.
I envision a future where all the physical objects in our living spaces are mapped to the digital world. Technology has advanced to an extent where hardware and software can be embedded into anything. Circuits have become smaller and smaller over the years. Sensors and micro-computers have shrunk in s...
As a graduate student, I will undertake research and coursework in Electrical Engineering to enhance my competencies in this field. I intend to complete my master's degree in order to pursue my doctorate. The research that I am most interested in pursuing at Northeastern University surrounds the optical properties of MEMS devices, and the development of substrate-based fast electro-optical interfaces. My interest in this area stems from my undergraduate study in MEMs development for tri-axial accelerometers.
Also, micro machining was performed on the substrate to improve the part’s feature resolution (cavities for electrical components and channels for the inks).
The microprocessor has changed our lives in so many ways that it is difficult to recall how different things were before its invention. During the 1960's, computers filled many rooms. Their expensive processing power was available only to a few government labs, research universities, and large corporations. Intel was founded on July 18,1968 by engineers, Gordon Moore, Robert Noyce, Andrew Grove, and Arthur Rock. Rock became Chairman, Moore was President, Noyce was Executive Vice President in charge of product development and worked with Moore on long range planning, and Grove headed manufacturing. The purpose of the new company was to design and manufacture very complex silicon chips using large-scale integration (LSI) technology. Moore and Grove's vision was to make Intel the leader in developing even more powerful microprocessors and to make Intel-designed chips the industry standard in powering personal computers. Moore and Noyce wanted to seek Intel because they wanted to regain the satisfaction of research and development in a small growing company. Although the production of memory chips was starting to become a commodity business in the late 1960's, Moore and Noyce believed they could produce chip versions of their own design that would perform more functions at less cost for the customer and thus offer a premium price. Intel's unique challenge was to make semiconductor memory functional. Semiconductor memory is smaller in size, provides great performance, and reduces energy consumption. This first started when Japanese manufacturer Busicom asked Intel to design a set of chips for a family of high-performance programming calculators. Intel's engineer, Ted Hoff, rejected the proposal and i...
...patches which gave better results. All of the fabrication was done by me using the method of chemical etching. The results of the fabricated model were compared experimentally by using vector network analyzer to those obtained from simulations using the simulation software.
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