Electrochemically controlled thinning of silicon
TL;DR: In this article, a method for precision thinning silicon integrated circuit slices has been developed whereby either n or p type regions may be selectively removed from material of opposite conductivity, which permits more complete advantage to be taken of many silicon IC structures.
Abstract: A method for precision thinning silicon integrated circuit slices has been developed whereby either n or p type regions may be selectively removed from material of opposite conductivity. The existence of a simple and economical means to attain precise thickness control permits more complete advantage to be taken of many silicon IC structures. For example, precise thickness control, together with anisotropic1 etching of isolation/separation slots, is expected to permit economical fabrication of high component density, air-isolated monolithic2 integrated circuits.
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01 May 1982
TL;DR: This review describes the advantages of employing silicon as a mechanical material, the relevant mechanical characteristics of silicon, and the processing techniques which are specific to micromechanical structures.
Abstract: Single-crystal silicon is being increasingly employed in a variety of new commercial products not because of its well-established electronic properties, but rather because of its excellent mechanical properties. In addition, recent trends in the engineering literature indicate a growing interest in the use of silicon as a mechanical material with the ultimate goal of developing a broad range of inexpensive, batch-fabricated, high-performance sensors and transducers which are easily interfaced with the rapidly proliferating microprocessor. This review describes the advantages of employing silicon as a mechanical material, the relevant mechanical characteristics of silicon, and the processing techniques which are specific to micromechanical structures. Finally, the potentials of this new technology are illustrated by numerous detailed examples from the literature. It is clear that silicon will continue to be aggressively exploited in a wide variety of mechanical applications complementary to its traditional role as an electronic material. Furthermore, these multidisciplinary uses of silicon will significantly alter the way we think about all types of miniature mechanical devices and components.
2,723 citations
Journal Article•
TL;DR: In this article, the advantages of employing silicon as a mechanical material, the relevant mechanical characteristics of silicon, and the processing techniques which are specific to micromechanical structures are discussed.
Abstract: Single-crystal silicon is being increasingly employed in a variety of new commercial products not because of its well-established electronic properties, but rather because of its excellent mechanical properties. In addition, recent trends in the engineering literature indicate a growing interest in the use of silicon as a mechanical material with the ultimate goal of developing a broad range of inexpensive, batch-fabricated, high-performance sensors and transducers which are easily interfaced with the rapidly proliferating microprocessor. This review describes the advantages of employing silicon as a mechanical material, the relevant mechanical characteristics of silicon, and the processing techniques which are specific to micromechanical structures. Finally, the potentials of this new technology are illustrated by numerous detailed examples from the literature. It is clear that silicon will continue to be aggressively exploited in a wide variety of mechanical applications complementary to its traditional role as an electronic material. Furthermore, these multidisciplinary uses of silicon will significantly alter the way we think about all types of miniature mechanical devices and components.
2,707 citations
Book•
30 Nov 2000TL;DR: The main aim is to provide an introduction to MEMS by describing the processes and materials available and by using examples of commercially available devices, and the concept of using MEMS devices as key elements within complex systems (or even microsystems!) is explored.
Abstract: If you've not been involved in MEMS (MicroElectroMechanical Systems) technology or had the cause to use MEMS devices, then you may wonder what all the fuss is about. What are MEMS anyway? What's the difference between MEMS and MST (MicroSystems Technology)? What are the advantages over existing technologies? If you have ever found yourself pondering over such questions, then this book may be for you. As the title suggests, the main aim is to provide an introduction to MEMS by describing the processes and materials available and by using examples of commercially available devices. The intended readership are those technical managers, engineers, scientists and graduate students who are keen to learn about MEMS but have little or no experience of the technology. I was particularly pleased to note that Maluf has dedicated a whole chapter to the important (and often difficult) area of packaging. The first three chapters provide a general overview of the technology. Within the first three pages we are introduced to the MEMS versus MST question, only to discover that the difference depends on where you live! The United States prefer MEMS, while the Europeans use the handle MST. (Note to self: tell colleagues in MEMS group at Southampton). A good account is given of the basic materials used in the technology, including silicon, silicon oxide/nitride/carbide, metals, polymers, quartz and gallium arsenide. The various processes involved in the creation of MEMS devices are also described. A good treatment is given to etching and bonding in addition to the various deposition techniques. It was interesting to note that the author doesn't make a big issue of the differences between bulk and surface micromachined devices; the approach seems to be `here's your toolbag - get on with it'. One of the great strengths of this book is the coverage of commercial MEMS structures. Arising as they have, from essentially a planar technology, MEMS devices are often elaborate three-dimensional creations, and 2D drawings don't do them much justice. I have to say that I was extremely impressed with the many aesthetic isometric views of some of these wonderful structures. Pressure sensors, inkjet print nozzles, mass flow sensors, accelerometers, valves and micromirrors are all given sufficient treatment to describe the fundamental behaviour and design philosophy, but without the mathematical rigour expected for a traditional journal paper. Chapter 5 addresses the promise of the technology as a means of enabling a new range of applications. The concept of using MEMS devices as key elements within complex systems (or even microsystems!) is explored. The so-called `lab-on-a-chip' approach is described, whereby complex analytical systems are integrated onto a single chip together with the associated micropumps and microvalves. The design and fabrication of MEMS devices are important issues by themselves. A key area, often overlooked, is that of packaging. Painstaking modelling and intricate fabrication methodologies can produce resonator structures oscillating at precisely, say, 125 kHz. The device is then mounted in a dual-in-line carrier and the frequency shifts by 10 kHz because of the additional internal stresses produced. Packaging issues can't be decoupled from those of the micromachined components. Many of these issues, such as protective coatings, thermal management, calibration etc, are covered briefly in the final chapter. Overall, I found this book informative and interesting. It has a broad appeal and gives a good insight into this fascinating and exciting subject area. Neil White
770 citations
TL;DR: In this paper, a cantilever-type micromachined silicon actuator based on the bimetal effect used extensively for the fabrication of temperature-controlled electrical switches is described.
Abstract: A cantilever-type micromachined silicon actuator based on the bimetal effect used extensively for the fabrication of temperature-controlled electrical switches is described. The silicon actuator consists of a Si-metal sandwich layer and an integrated poly-Si heating resistor as a driving element. Due to the low heat capacity of the transducer element, a high temperature increase per input power unit can be achieved. For a (Si-Au)-cantilever-type actuator, 500- mu m long and several micrometers thick, a specific deflection of approximately 0.1 mu m/K at the free end has been measured. The design considerations, fabrication process, and experimental results of the actuator are discussed. >
315 citations
TL;DR: A review of micro resonant force gauges is presented in this article, where a theoretical description is given of gauges operating in a flexural mode of vibration, including a discussion of non-linear effects.
Abstract: A review of micro resonant force gauges is presented. A theoretical description is given of gauges operating in a flexural mode of vibration, including a discussion of non-linear effects. Gauge factor and quality factor are defined and their relevance is discussed. Performance issues such as sensitivity, stability and resolution are addressed. Design aspects, including the means for excitation and detection of the vibration, and examples of silicon microfabrication technologies are described.
272 citations
References
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[...]
TL;DR: A process has been developed to batch-fabricate beam-lead transistors, integrated circuits, and other components, where the leads serve a structural and protective as well as electrical function as mentioned in this paper.
Abstract: A process has been developed to batch-fabricate beam-lead transistors, integrated circuits, and other components, where the leads serve a structural and protective as well as electrical function. Platinum silicide ohmic contacts, titanium and platinum sputtered layers, and electroformed gold beam leads constitute the metallurgical structure of the devices described. Test transistors have survived 350°C aging for hundreds of hours in corrosive ambients, and centrifuging at 135,000 g's.
156 citations
01 Jan 1967
TL;DR: Anisotropic silicon etches which preferentially attack the {100} and {110} crystal planes have been used to form narrow well-controlled isolation slots in silicon beam-leaded integrated circuits as discussed by the authors.
Abstract: Anisotropic silicon etches which preferentially attack the {100} and {110} crystal planes have been used to form narrow well-controlled isolation slots in silicon beam-leaded integrated circuits. The etches of interest are characterized by etching rates, R, on the low order crystal planes in the order R{100} > R{110} > R{111}, and for which R{111} is effectively zero.
11 citations