MEMS the word as micro devices catch on

Once obscure, microelectromechanical systems are poised to enter the consumer products marketplace in force.

13 min read
Microelectromechanical systems are an engineering marvel that mainstream industries such as automaking, medical devices and other high-precision manufacturers have integrated into their products for years.

A 40-year-old technology, MEMS devices by the 1990s became commonplace in airbag sensors and manifold air pressure sensors in cars, inkjet printer heads and blood pressure monitoring devices, just to name just a few.

Each of these many industrial sectors account for hundreds of millions of MEMS devices sold every year in a marketplace now exceeding $10 billion a year in sales. Today, though, the MEMS industry is poised to enter the multibillion-dollar consumer products marketplace in force, led by major specialized semiconductor manufacturers such as Texas Instruments, Analog Devices and Robert Bosch, as well as a host of creative, venture-capital-backed start-ups.

These companies are pushing MEMS devices into increasingly sophisticated display technology, motion detection (to protect cell phones and laptops from breaking during a fall), even microphones. The growing range of MEMS applications may soon encompass most of the massive global consumer electronics marketplace. "No other industry is experiencing such tremendous growth as the consumer electronics industry," says Jorg Schiffer, the marketing director at the new MEMS consumer products sensors division of Robert Bosch, one of the world's largest suppliers of MEMS sensors to the automotive industry.

Some of these consumer-related MEMS applications are already entering the marketplace, others may be only a few years away from commercialization. And if the market develops as analysts expect, the total worldwide market for MEMS will grow from $11.5 billion in 2004 to $24 billion in 2009, according to Guido Tschulena, president of Sgt Sensor Consulting of Wehrheim, Germany. Consumer products will help drive the doubling of those sales figures, especially digital displays in TVs, mobile phones and other handheld devices, laptop computers and digital cameras, microwaves and washing machines.

As impressive as those projections sound, supplying consumer goods manufacturers with new MEMS devices may not be that easy for MEMS companies. The consumer products market is considerably riskier than traditional precision industries; fast time to market and low prices rule supreme. Gaining entry into some high-volume consumer product applications can hinge on pennies in the most price-sensitive applications.

Can these exceedingly complex devices make the grade over already well-established technologies or other, competing technologies? The answer could well determine the direction in which key consumer products evolve and converge over the next decade, in style and performance, power efficiency and endurance. The answer also resides in an understanding of the complexity of the MEMS manufacturing process in different consumer products markets.

A typical MEMS device is indeed an engineering marvel that brings together integrated circuit manufacturing processes with "micromachining" to etch away or build up silicon structures of moving parts.

MEMS technology is an outgrowth of the highly sophisticated semiconductor industry. Microelectromechanical systems integrate moving mechanical elements, sensors and electronics on pieces of silicon. A typical MEMS device is indeed an engineering marvel that brings together integrated circuit manufacturing processes with "micromachining" to etch away or build up silicon structures of moving parts. The result is a microscale device that combines computational ability with the sensing and control functions of exquisitely sensitive sensors.

The first commercial MEMS devices evolved from the mid-1960s, reaching high-volume production in the 1990s, according to Roger Grace, a MEMS marketing consultant in Naples, Fla. Since then, industries that absolutely require high-precision MEMS devices, such as automakers, have continually integrated them into high-priced products, passing the cost onto consumers. Meeting the low price demands of mass production (yet low safety) manufacturers of electronic mobile consumer products at a high volume is a very different challenge for MEMS suppliers.

For starters, few MEMS devices are truly "monolithic," meaning they combine the micromachined silicon structure and electronics on the same chip. More often, the micromachined part and electronics are fabricated separately and then wire bonded together in a single package. George Hsu, president of 1-year-old start-up Sensor Platforms and the inventor of a MEMS sensor-based electromagnectic compass, says creating the electronic circuitry that makes a MEMS device usable in a mobile electronics product can be expensive, time consuming and perhaps outside the core competency of most MEMS producers. How difficult this is depends on the consumer products sector that MEMS companies are targeting--display technologies, sound technologies or sensor technologies.

Tiny light
Digital television displays are the most significant and growing arena for MEMS, courtesy of Texas Instruments, which dominates the optical MEMS market for digital displays with its digital light processing technology, or DLP.

The heart of DLP is an array of up to 2 million hinge-mounted aluminum micromirrors, known as digital micromirror devices, or DMDs. The mirrors--each about 14 microns wide, or one-fifth the width of a human hair--reflect a digital image from a light source onto a screen. The mirrors tilt toward or away from the light source, creating light or dark pixels; white light, such as a florescent light, is projected through a color wheel to create color.

TI began developing its DLP technology in its research lab 16 years ago, according to DMD program manager Mike Mignardi. After demonstrating its reliability in 1990, the company established an internal business unit, selling its first product in 1996. TI developed DLP technology from in-house resources, and it remains a vertically integrated process within TI, from production of the micromirrors and electronics to product testing.

DLP technology today accounts for one in five very large (more than 40-inch diagonal) digital TV displays, where it competes with more established technologies such as the venerable cathode ray tube as well as liquid crystal and plasma displays, and new technologies such as organic light-emitting diodes. And it's an important and growing market. Overall, digital TV sales are projected to grow from about 4.3 million this year to 9 million units in 2007. Other major markets for MEMS displays are DLP front projectors and commercial cinema.

TI's Mignardi argues that DLP technology is price competitive with other digital TV display technologies and also offers extremely sharp images with no burn-in or fading of the screens. TI is launching a new generation of DLP technology in the fourth quarter of this year that uses solid-state, light-emitting diodes instead of conventional white light, enabling displays for portable display uses.

So far, TI's DLP technology faces no competition, Mignardi says. Silicon Light Machines, a subsidiary of Cypress Semiconductor, in 2000, developed a MEMS display technology called Grating Light Valve, which uses ribbonlike reflective elements on the surface of a silicon chip that move up or down to deflect light. Silicon Light licensed its technology to Sony in July 2000, but since then both companies have been silent about any product launches and did not return calls for comment.

Three other U.S. start-ups are developing optical MEMS for displays: 2-year-old Miradia, 7-year-old Reflectivity and 4-year-old Keyotee. Only Reflectivity, however, claims to have working prototypes of its display chips. The others are still in development.

Then there's San Diego's Qualcomm, which is betting that a new MEMS display technology that Iridigm Display is developing will be the next big thing in cell-phone displays. Qualcomm was an early investor in Iridigm Display and acquired it outright in 2004. It was interested in Iridigm's reflective display technology, which consumes much less power than liquid crystal displays and can be viewed in bright sunlight.

Borrowing an idea from nature found in iridescent butterfly wings, which contain microscopic cavities that cause light to interfere with itself, creating shimmering iridescent colors, Iridigm's interferometric modulator, or iMod, display produces light through interference. The display contains special films and mirrors that move up and down, causing light that reflects off the film to interfere with light bouncing off the mirror. The interference between the two produces color.

Today, quartz crystals are combined with timing semiconductor chips to perform timing functions to synchronize signals, which is about a $2.5 billion industry.

Greg Heinzinger, senior vice president and general manager of the Qualcomm MEMS Technology subsidiary, says the iMod technology consumes up to 90 percent less power than LCD displays because it uses ambient light rather than white light. Ambient light reflects light from external light sources, such as the sun or a lamp, consuming much less power than LCD screens, which depend on white light, which is generated as backlight from, say, a fluorescent light behind the screen.

The screen is more akin to paper and is easier for the eye to focus on, he explains. He also expects manufacturing costs to be lower because there are fewer manufacturing steps. Heinzinger says the iMod technology has big potential in cell phone displays because it will allow handheld electronic devices to be used in "always on" mode. The display can be viewed under many light conditions and can operate in a wide temperature range.

Qualcomm signed an agreement with Prime View International of Taiwan to manufacture the displays. PVI is scaling up the manufacturing, a roughly 18-month process, and Qualcomm is negotiating with potential customers to launch the product, Heinzinger says.

Complex sounds
Knowles Acoustics, a division of Knowles Electronics, today produces so-called condenser microphones found in many portable electronic devices, radios and corded telephones--a market of about 1.5 billion units. After 20 years of strides in reducing size and improving reliability, however, condenser microphones by the 1990s were reaching a point of diminishing returns, says Angelo Assimakopoulos, the company's director of new-business development.

So about 12 years ago, Knowles, a "fabless" MEMS company that farms out the micromachined silicon and electronic components and then assembles them in-house, began development of a silicon MEMS microphone, introducing its first commercial product in 2003. The microphone consists of a silicon MEMS device that houses the electronic components and integrates those two applications on a surface-mounted printed circuit board package.

Mike Adell, the company's director of product management, says the silicon microphone is more robust than the condenser microphone, with a wider temperature operating range. It's also easier to manufacture, requiring less floor space and lending itself to automated assembly.

To help reduce manufacturing costs, Knowles invested in a new automated assembly line to boost throughput and consistency and thus gain a much higher yield, Adell says. He adds that its silicon microphones are now price competitive with condenser microphones, which the company still manufactures. He says Knowles is producing "multimillion" units per month and plans to boost production over the next several years. He claims Knowles has gained more than 50 percent market share of its existing microphone business among certain mobile phone manufacturers.

Such numbers attracted a suitor, Dover, a diversified manufacturer based in New York, which in August announced that it was acquiring Knowles for $750 million. Marlene Bourne, senior director of research at Global Crown Capital, an investment firm in San Francisco, says Knowles' silicon microphones are already shipping in significant volumes as a result of their significant size and better quality. She expects to see a price advantage as production volumes begin to ramp up, especially as so far no other competitors have emerged.

Keeping time
SiTime, a MEMS start-up in Sunnyvale, Calif., aims to replace quartz resonators and oscillators--components widely used in the electronics industry to keep time and enhance communications--with silicon MEMS. Kurt Petersen, the company's CEO, in 2004 obtained an exclusive license for the technology from Germany's Robert Bosch, which invented the technology and invested in the start-up alongside venture capital firms New Enterprise Associates, Greylock Partners and CampVentures.

Quartz crystals' most recognizable application is in wristwatches, but they are also used in many types of electronic devices such as cell phones, cameras, camcorders, printers and video screens. Petersen pegs quartz crystals as a $3.5 billion business, accounting for around 10 billion quartz crystals produced every year. He expects the growth of wireless communications to drive that number up.

Today, quartz crystals are combined with timing semiconductor chips to perform timing functions to synchronize signals, which is about a $2.5 billion industry. SiTime's strategy is to replace the quartz crystals and timing chips with a single silicon MEMS device, which together would account for a $6 billion market.

Petersen says the start-up's first application will be a programmable oscillator, which enhances accurate timing in complex electronic products, for wireless devices such as cell phones. Combining the oscillator on the chip itself offers cell phone manufacturers fewer parts, smaller size and lower power consumption, he explains. Two silicon oscillators can be combined on the same chip to combine communications and timing functions, he says.

He expects to launch his first product during first quarter 2006 and plans to follow that with a MEMS device for cell phones that is 20 percent the size of current devices. Future generations of products will target communications functions and, eventually, wristwatches.

MEMS industry consultant Roger Grace believes silicon MEMS will displace quartz oscillators that have been in the marketplace for many years. "This product provides the same functionality as a quartz oscillator but at a much better price and much better size," he says.

Making these types of MEMS devices at their requisite microscale, however, requires precision that is exceedingly difficult with traditional chip and machining fabrication techniques. The need to produce MEMS components that are highly precise, with smooth surfaces, and steep sidewalls has led to the development of exotic fabrication techniques that are reaching into new areas.

These new manufacturing processes enable traditional MEMS manufacturers to crack the consumer products components marketplace. One such manufacturing process is known as LIGA, which uses lithography, electroforming and molding to create three-dimensional microscale parts of metal and plastics. The process was developed at the Karlsruhe Research Center in Germany in the 1980s, but it didn't take hold in the industry until MEMS manufacturers embraced it to attack the consumer products marketplace.

Case in point: Angstromquelle Karlsruhe, known as ANKA, a private company funded by the German government, which uses the LIGA process to make tiny precision components in Swiss watches. ANKA has just signed on to produce a lever and escapement wheel for mechanical watches produced by H. Moser, a Swiss watchmaker.

There is a lot of risk, and sensor companies tend to invest a lot of resources.
--Vic Chatigny, vice president, MSI sensors division

Marcus Arndt, president of ANKA, says he's talking to additional watchmakers, and sees applications for using the process to form precision components in the biotech and aerospace industries. He says the LIGA process is well suited to produce precision optical components to steer light and detect wavelengths.

Sensor subtleties
In July of this year, Robert Bosch, one of the largest producers in the world of MEMS sensors for the automotive market, established a division, Bosch Sensortec, to target MEMS for consumer devices and industrial goods. The division recently introduced its first product, a so-called triaxis accelerometer for consumer electronics applications.

Accelerometers protect sensitive electronic products when they fall by detecting an object in free fall and shutting down the electronics. Samples are available and production is planned for the end of the year, says Jorg Schiffer, the group's marketing director. He points to cell phones and laptop computers as among the key segments his company will target--a new application that only MEMS devices can offer.

According to Bosch Sensortec CEO Frank Melzer, the division will collaborate with the company's automotive division, which is located nearby. Melzer predicts Bosch will hit the 100 million mark in annual production of MEMS sensors this year. He says the new division will be able to leverage off the automotive division's production capacity as well as its design know-how.

Other traditional MEMS makers are pushing in this direction, too. Measurement Specialties in Hampton, Va., is a MEMS supplier now heavily involved in the consumer products business. MSI supplies a range of MEMS accelerometers, pressure sensors, and load cells that go into various consumer products.

"There is a lot of risk, and sensor companies tend to invest a lot of resources," says Vic Chatigny, vice president of MSI's sensors division, before they know a market will materialize. Moreover, consumer products makers demand MEMS sensors for under $2, he says, compared with automotive safety MEMS devices that sell for $5 to $10 apiece. MSI manufactures MEMS chips that go into bathroom scales, consumer tire pressure gauges, home-care blood-pressure pumps, washing machines, dryers and microwave ovens.

But MEMS consultant Guido Tschulena says these types of MEMS temperature sensors or accelerometers are also suited for mobile consumer electronic products to ensure they operate longer. Indeed, Freescale Semiconductor introduced a so-called triaxis low-gravity accelerometer to protect consumer products from damage. Freescale applications engineer Michelle Clifford predicts that more accelerometers will be designed into consumer electronics products as companies better understand their capabilities. She ticked off six new applications: tilt, movement, position, shock, vibration and free-fall detection.

Christophe Lemaire, customer marketing manager for Analog Devices, says his company is counting on consumer products manufacturers to seek out these new features to differentiate their brands. Analog Devices now supplies accelerometers to IBM for drop detection to protect the hard drives on ThinkPad laptop computers. Cell phones, he says, are next on the list.

Similarly ambitious is InvenSense, a 2-year-old, venture-backed start-up that is developing dual-axis MEMS-based gyroscopes for the consumer electronics market. Gyros measure angular acceleration around an axis for image stabilization in digital cameras, camcorders, cell phones and camera phones, according to Dan Goehl, director of business development.

InvenSense, a fabless MEMS company that farms out the work of creating the actual device, has driven down the manufacturing costs, using less expensive bulk silicon technology and wafer bonding that Goehl claims lowers packaging and testing costs. But MEMS sensor makers may soon need to take another approach to help trim costs, argues George Hsu of Sensor Platforms. He says he has created a chip that is flexible enough to be used with a wide variety of MEMS sensors. Hsu says the chip can save MEMS producers significant manufacturing costs by eliminating the need to customize the electronics for each MEMS device.

Now that would do the trick--mass-producing MEMS devices for any consumer products application. That's a bold ambition for a 1-year-old start-up, but then again the chip industry is nothing if not creative and flexible.

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