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APPLICATION OF MEMS TECHNOLOGY IN CONSUMER ELECTRONIC PRODUCTS

Today, consumer electronic products are mostly wireless mobile devices such as laptops, iPhones and iPods, and gaming controllers. There are several reasons why companies are pleased with the market pull associated with consumer electronics. First of all, the traditional markets for MEMS technology such as automotive and industrial applications has declined over the last year. And secondly, the potential number of MEMS devices that can be supplied to the consumer market is in the billions. This last point is relevant in more than one ways in that because of this potential high volume of MEMS devices, semiconductor manufacturers such as TSMC are all of a sudden interested in production of MEMS.

Let's look at the potential application of MEMS technology in consumer electronic products. The three MEMS devices that will see a rapid growth are Si microphones, accelerometers and RF MEMS. Nokia gave an excellent presentation during the MEMS Executive Congress in November 2008 (downloadable for MEMS Industry Group Members).

Just a year later, the list of MEMS devices that are designed for cell phones is growing, including; Pressure sensors and Gyroscopes for location based services (think GPS), Micromirrors for image projection (think Pico-Projector which still has not proven itself), Microdisplays for ultra low power displays and better picture in sunlight (think Mirasol), some devices inside which the consumer will never see such as Variable capacitors, RF Switches, FBAR, BAW and Oscillators. And micro fuel cells for longer battery life.

Most of our interaction with computing devices has been through a keyboard, a mouse, and a screen or display. Smart phones have removed the actual mouse and keyboard and introduced the touch sensitive screen but MEMS technology is introducing the next level of interaction, motion sensing. Today seven out of ten games for the iPhone use the built-in MEMS accelerometer as a smart controller that allows users to tilt, shake and otherwise use motion to control games. Read this article about Invensense and their success in MEMS gyroscopes

Image of the Board inside an iPhone pointing out the MEMS accelerometer

Nombre: Lenny D. Ramirez C.
Asignatura: CRF
Dirección http://info.coventor.com/memsahead/bid/34336/APPLICATION-OF-MEMS-TECHNOLOGY-IN-CONSUMER-ELECTRONIC-PRODUCTS
Ver blogg: http://lennyramirez-crf3.blogspot.com/

"PCB-MEMS"

Una tendencia cada vez más presente en la fabricación de dispositivos electrónicos ultra-pequeños es mediante el uso de MEMS con materiales exclusivos para los circuitos impresos.

(EOL/Oswaldo Barajas).- La evolución electrónica a lo largo de la revolución tecnológica industrial ha dado paso a una sub-categoría de aplicación sectorial denominada “Nanotecnología” ó MEMS, donde los componentes que conforman las estructuras llegan a medir milésimas partes de un milímetro.

A través de este artículo analizaremos el uso de algunos materiales empleados en la tecnología de circuitos impresos utilizados para la fabricación de microsistemas y algunas de las ventajas que este uso dispensa durante el proceso de fabricación de PCB más económicos en comparación con la tecnología convencional basada en Silicio.

Para la producción de los microsistemas, los materiales más usados como sustratos de partida son el FR-4, una substancia conformada por fibra de vidrio e impregnada con una resina epóxica resistente a las llamas; asimismo el uso de Teflón especialmente aquellos pertenecientes a los grupos GT y GTX, Poliamida, Poliestireno y Poliestireno Entrecruzado, éstos últimos con propiedades mecánicas más pobres pero con un mayor desempeño eléctrico.

En el caso de las láminas ocupadas para la generación del material, aleatoriamente se utilizarán aquellas que sean finas a base de polímero flexible como Kapton de la firma DuPont, ó bien la LCP, con las cuales se formarán las estructuras multi-layer (poli-capas).

Cabe señalar que la clase de PCB que se obtengan como resultado del uso de los materiales antes mencionados, son también llamadas como circuitos flexibles ó rígidos-flexibles, y aunque son complicados para fabricarlos siendo por consiguiente altamente valorados por sus distintas aplicaciones, pues debido a su capacidad flexible, pueden ahorrar espacio en los mismos circuitos impresos tales como las hallados en cámaras o audífonos.

En esta etapa los ingenieros añaden otros pasos para la fabricación de los circuitos impresos a fin de prepararlos para la creación de las estructuras nanotecnológicas.

Algunas de las ventajas identificadas por parte de algunos investigadores y expertos del tema son:

• Una simplicidad en la elaboración de PCBs y de manera más barata a comparación de aquella tecnología con Silicio.

• Asimismo se ha visto una reducción en el tiempo de prototipado, convirtiéndola en más rápida.

Para la fase de fabricación se requiere de un sustrato de partida, en este caso el FR-4 y láminas de Cobre ya sea de 32, 64 o 128 μm, de esta manera el Cobre sometido a labores químicas para su eliminación producirá los bordes de los lados del canal del fluidito. En este momento se utiliza otra lámina de Cobre para cerrar el canal de forma vertical y a través de otras técnicas de adhesión especial se continúa con el trazo de cerrado. Finalmente se hace uso de la Deposición de Epoxis, cuyas resinas epoxídicas son un tipo de adhesivos llamados estructurales o de ingeniería el grupo incluye el poliuretano, acrílico y cianoacrilato; sirven para pegar gran cantidad de materiales, incluidos algunos plásticos, y se puede conseguir que sean rígidos o flexibles, transparentes o de color, de secado rápido o lento, además pueden servir como profusores en el encapsulado de los circuitos integrados y los transistores.

Cuando se llega a este paso, lo siguiente en la lista es precisar el objetivo estructural que necesitamos para nuestro proyecto, pues cabe señalar que el acomodo de las capas a manera de un sándwich conformado por capas lograremos una variedad de estructuras diversas.

Ensamble de las capas

En este parte del proyecto, el ensamblado tiene que llevarse a cabo con el mayor sentido de cuidado, pues resulta muy delicado en su manufactura.

En la siguiente imagen podemos observar una adecuada manipulación de la técnica de ensamblado para los PCB-MEMS, donde la sección del canal 28 μm x 100 μm y en la imagen inferior se aprecia el espesor inicial de la resina a 4 μm.

En las imágenes anteriores se describe el montado aconsejado de los Nano-PCBs, y en ambos casos se identifica la presencia de Cobre, ya que este metal es multi-funcional al permitir realizar cavidades fluiditas, dar paso a la conductividad de las señales eléctricas, calentamiento en corrientes elevadas y otros factores como la resistencia eléctrica y capacitancia, por mencionar algunos. Asimismo con este método se logra un amplio espectro de aplicaciones como calentadores o sensores de temperatura, detectores de burbujas, sensores de presión capacitivos, microbombas y válvulas eléctricamente controladas y foto-litografía tecnológica de punta que elimina el uso de máscaras.

Nombre: Lenny D. Ramirez C.
Asignatura: CRF
Dirección: http://nanoudla.blogspot.com/2009/10/pcb-mems.html
Ver blogg: http://lennyramirez-crf3.blogspot.com/

MEMS optical switch promises next-gen networks

Multimirror MEMS device can switch up to 80 channels

A prototype multichannel optical switch with a speed of 1 ms promises to provide the fast optical cross-connect required for the development of all-optical communication networks.

With package dimensions of only 150 x 400 x 300 mm, a prototype 80-channel optical communications switch from telecommunications manufacturer Fujitsu (Tokyo, Japan) has a switching speed of 1 ms�the fastest of any multichannel switch available. By eliminating the need to convert light into electricity during the switching process, the 3-D optical MEMS device is expected to enable the development of the optical cross-connect systems essential for next-generation optical transmission networks.

The switching speed is achieved by using a notch filter to eliminate mechanical resonance by removing the resonant frequency of the comb-driven MEMS mirrors from the driving electrical waveform. In addition, a feedback loop with a built-in control function compensates for variations in the power levels of each channel, eliminating the need for external variable optical attenuators and providing an optical power stability of ±0.5 dB.

The device uses a folded-optical-switch configuration in which the input beam is reflected though an angled retro-reflector that halves the optical path and reduces device size. Using a comb-shaped electrode structure to drive the MEMS mirrors results in greater driving power than with a planar structure.

The device is currently being evaluated for the best manner to bring the technology to market. A variety of platforms within the company's product line are expected to contain the device.

A prototype MEMS optical switch promises to allow the creation of next-generation fiber networks

Nombre: Lenny D. Ramirez C.
Asignatura: CRF
Dirección: http://www2.electronicproducts.com/MEMS_optical_switch_promises_next-gen_networks-article-olap-jan2004-html.aspx
Ver blogg: http://lennyramirez-crf3.blogspot.com/

MEMS Technological Developments

MEMS stands for Micro-Electro-Mechanical Systems and if that makes no sense to you, don’t worry—lots of people are just discovering this new technology for themselves.

This unique system combines sensors, actuators, mechanical components, and electronics on one silicon base; essentially it is a type of glorified computer chip.

Typically, microfabrication is used to apply the various elements to their silicon wafer.

The many components that go on the wafer all have their different manufacturing processes: electronics are typically made separately using integrated circuit, or IC, process sequences (this can include BICMOS, CMOS, or Bipolar techniques.) The micromechanical elements, on the other hand, are often micromachined.

This means that a high-tech device, sometimes a laser cutter, etches away parts of the silicon chip, or sometimes areas are added in order to create the end result.With the advent of MEMS technology, the techno-geek dream of having an entire system on one chip has become reality.

Prior to MEMS, two separate components were required to work in tandem: the microelectronics on a silicon chip, and the micromachined mechanical elements in a different format. Combining them into one efficient MEMS system eliminates several steps of production as well as the need for a connector between the two elements.

This allows for the development of “smart” products because microelectronics can perform delicate computational functions which are then enacted by the fine-tuned physical accuracy of microsensors and microactuators. Smart MEMS products with these kinds of capabilities open up a whole new world of applications and technological design possibilities.

Understanding what the different parts of a MEMS chip are all about becomes easy when you think of the microelectronic integrated circuits as the brains of the operation, sending signals to the microsystems that will then act as eyes, arms, legs, etc. to carry out the desired action.

Once the microsensors have received the circuits’ directions they sense their environment, measuring different factors such as thermal readings, biological presence, mechanical functions, chemicals, optical information, and magnetics—this information is then relayed back to the “brain” for more decision-making, and all of these steps take place in a matter of seconds.

The fact that MEMS microchips can to some degree make their own decisions fits in with other innovations in the field of nanotechnology; nanotech scientists have always made it plain that they are working toward an ideal autonomous product (which will perhaps reach its peak expression in the nanorobot, but is nevertheless an integral part of most nanotechnology products.

Decision-making capabilities as well as sensors that allow the MEMS chip to detect its environment are key factors in its superior functioning. The actuators usually perform functions like physically moving their entity, positioning in small increments, regulating data, pumping fluids or air, and filtering various substances.

Typically the functions associated with a device that uses MEMS technology are somehow related to controlling the surrounding environment in order to achieve a desired outcome. Before MEMS technology other devices were capable of doing similar tasks, but to date none has been as efficient as MEMS.

This is because MEMS chips can typically be made using batch fabrication manufacturing in much the same way that integrated circuits are produced, which renders them extremely low in cost as well as more functional, more reliable, and also more sophisticated. And perhaps the best part is that all of these superior features can be combined onto one small silicon chip.

Almost every industry can benefit from having such fine-tuned technology at their disposal. The dual nature of MEMS systems allow them to bridge gaps between previously unassociated subjects, such as microelectronics and biology, for example.

Biotechnology has benefited from MEMS developments like the Polymerase Chain Reaction microsystems which can be used to amplify and identify DNA. MEMS has also given rise to Scanning Tunneling Microscopes, which are made with the micromachining process; biochips that have the ability to scan and detect chemical and biological agents which may be hazardous; and microsystems that render drug screening and selection more effective.

In the communications field, high frequency circuits have been upgraded with MEMS technology so that they can perform better and more cost-efficiently. Electrical elements of these circuits tend to benefit the most, such as their tunable capacitors and their inductors—and best of all, production and installation become a simplified process because no integration is required when MEMS is used.

The mechanical switches used to run these systems also show large improvements when upgraded with MEMS. The only drawback for MEMS communications devices lies in their reliability and packaging; in some cases the same product has had consistency issues across the board and resolving these problems will prompt greater acceptance in the marketplace.

Accelerometers are used for a variety of scientific applications, and MEMS can improve these functions too. MEMS accelerometers are quickly rendering their conventional counterparts obsolete, especially when it comes to airbag deployment in automobiles

MEMS accelerometers can sense not only the fact that an impact has occurred, but they can also judge the speed, intensity, and several other crash-related factors in order to determine the rate at which an airbag system should deploy and also how much of the airbag to release.

This has the potential to save lives, since too much or too little airbag has often resulted in crash deaths. The traditional accelerometer is actually a series of devices integrated together at various points throughout the vehicle, with their attendant electronics positioned near the airbag.

This system is not only clunky and awkward, but allows the system parts to become cut off from each other at several points, possibly resulting in complete lack of accuracy or even a total system malfunction.

This conventional accelerometer package typically costs about $50 per vehicle. MEMS nanotech accelerometers, on the other hand, can integrate all the fundamental parts onto one small silicon chip. Such an approach renders them lighter, more accurate, and less expensive—MEMS accelerometers tend to average about $5 or $10 per vehicle, saving the consumer money many times over.

Nombre: Lenny D. Ramirez C.
Asignatura: CRF
Dirección: http://nanogloss.com/mems/mems-technological-developments/
Ver blogg: http://lennyramirez-crf3.blogspot.com/

New MEMS sensor probe may help clinicians distinguish cardiac emergencies

The researcher reveals that he intends to build a novel tool that should aid clinicians in differentiating between cardiac emergencies. This would allow clinicians to efficiently recognize chronic problems that may require immediate surgery and those that can be taken care of simply with drugs and lifestyle change.

An inside view of the interior surface or the lumen of the arteries that feed the heart are provided by angiograms that are images made by catheters. The images often exhibit deposits of a dangerous fatty substance termed plaque. However plaque is known to occur in various forms.

While some are metabolically stable and may be fixed firmly in the lumen, others are known to be less viscous and have high chances of dislodging and causing heart attacks. The former may be treatable with diet, exercise and medication and the latter seems to need immediate primary coronary intervention (angioplasty) or by-pass surgery. And current angiogram techniques seem to be incapable of distinguish the types of plaque.

“Distinguishing stable from unstable plaque remains an unmet clinical challenge,” said Hsiai, who holds both M.D. and Ph.D. degrees.

The researcher hopes that the innovative Microelectromechanical System (MEMS) sensor helps in altering this situation. The system claims to utilize minute heat perturbations as a proxy for blood flow. It may help in detecting changes in bulk resistance for plaque characteristics. Apparently, it can potentially be part of the same catheters used for angiograms.

Additionally the lab reveals that this sensor can efficiently make the distinction between stable and unstable plaque. In laboratory examinations, it could distinguish between specimens of plaque clogged arteries that had been extracted from rabbits fed a special plaque-producing diet. Besides, another configuration of the same sensors claims to measure the forces on the artery walls produced by blood flows. It may thus aid in recognizing spots where back currents may be promoting plaque formation.

“Coronary artery disease is rising worldwide because of changes in diet in developing nations, and parallel increases in obesity and diabetes in the West,” said Hsiai.

The researcher’s next step is to integrate the MEMS sensors into angiogram catheters. He intends to show that they can accurately make the same distinctions, primarily in animals and then in human subjects.

According to the National Institutes of Health, nearly one million Americans are known to undergo angiograms. Heart attacks claim to be the leading cause of deaths in the United States and seem to account for approximately one-fifth of total annual mortality as per the American Hearth Association.

A plaque whether stable or related to heart attack may be difficult to identify with present anigiogram methods. However a new Microelectromechanical System (MEMS) sensor probe to be developed by Viterbi School biomedical engineer and cardiologist Tzung John Hsiai could be potentially useful in prevalent angiogram catheters

Nombre: Lenny D. Ramirez C.
Asignatura: CRF
Dirección: http://www.healthjockey.com/2009/12/17/new-mems-sensor-probe-may-help-clinicians-distinguish-cardiac-emergencies/
Ver blogg: http://lennyramirez-crf3.blogspot.com/

Dispositivos mecánicos ultra pequeños MEMS

Para fijar ideas podemos decir que en el microprocesador de una computadora actual tenemos unos 50 millones de transistores por cm2, lo que implica una dimensión típica de 1 m2 por transistor, con un detalle de los contornos del orden de los 100 nm. Esta miniaturización ha permitido reducir componentes electrónicos voluminosos dando a lugar a equipos portátiles, que de otra manera no se emplearían (radios personales, notebooks, teléfonos celulares, etc.) con un panorama de aplicaciones increíble.

¿Y qué tal si lográramos reducir máquinas enteras?

Se podrían construir, por ejemplo, pequeños dinamómetros (sensores de fuerza) que colocados en las patas de una cucaracha nos permitirían entender cómo efectúa y distribuye las fuerzas para lograr un desplazamiento tan eficiente en superficies no horizontales. Esta información nos llevaría eventualmente a construir nuevos dispositivos mecánicos en la escala humana para simular las técnicas de desplazamiento de estos insectos. También se podría armar, en dimensiones muy reducidas, un dispositivo ubicado en el cuerpo de un paciente (“lab on chip”), que analizara su sangre y que, en función de los resultados, inyectara fármacos en las dosis adecuadas, y hasta podría enviar una señal de alerta para que el paciente fuera atendido de urgencia. Estas máquinas funcionarían en definitiva como pequeños robots que nos permitirían la realización de un conjunto de tareas hasta hoy inaccesibles en un mundo de escala micrométrica.

La miniaturización de máquinas electromecánicas o MEMS ya es una realidad de nuestros días. Efectivamente, estos microdispositivos ya se emplean para la realización de acelerómetros, presentes en los airbags de los autos para determinar el momento justo en que se produce un choque y disparar así el mecanismo de inflado de las bolsas. Este mismo tipo de MEMS se emplean como elementos de navegación, particularmente en la industria aeroespacial, pero también se prevén aplicaciones como sensores de presión, temperatura y humedad. Se los ha incorporado en marcapasos, para sensar la actividad física del paciente y modificar su ritmo cardíaco. Para evitar falsificaciones de firmas, se ha pensado incorporar estos acelerómetros en lapiceras. De esta manera, no sólo estaría registrado el trazo particular de la firma sino también las velocidades y aceleraciones que le imprimió la mano a la lapicera mientras se firmaba, lo cual haría mucho más difícil su falsificación. También se emplean MEMS en los cabezales de las impresoras de chorro de tinta, produciendo la evaporación controlada de la tinta en el momento justo, y gracias a la entrega localizada de calor. Además de la ventaja del tamaño de estos dispositivos está el hecho de que se los puede fabricar de a miles abaratando notablemente su costo de fabricación.

Esquema del dispositivo que corrige las deformaciones de la imagen producidas por la turbulencia de la atmósfera terrestre. La óptica adaptable, realizada mediante MEMS, permite neutralizar este efecto y obtener una resolución angular adecuada como para distinguir objetos estelares que de otra manera se encontrarían confundidos en una imagen borrosa.

 

Nombre: Lenny D. Ramirez C.
Asignatura: CRF
Dirección: http://aportes.educ.ar/fisica/nucleo-teorico/estado-del-arte/nuevas-herramientas/dispositivos_mecanicos_ultra_p.php
Ver blogg: http://lennyramirez-crf3.blogspot.com/