Electronic Design

MEMS Gaining Acceptance Despite Technical Challenges

MEMS technology has made significant strides in commercialization. Yet it still faces tough technical hurdles, notably packaging and testing, in reaching the mainstream. That was the message conveyed at the 8th International Conference on the Commercialization of Micro and Nano Systems (COMS 2003), held in Amsterdam, the Netherlands, Sept. 8-11, sponsored by the Micro and Nano Commercialization Education Foundation (MANCEF).

One reason for MEMS' penetration of commercial markets has been the slowly widening pool of foundries that offer low-cost production services. Such services have surfaced due to the greater availability of knowledge about cost-effective manufacturing of MEMS (microelectromechanical-system) devices. While most MEMS design houses prefer to make their own products rather than use outside foundries, market data indicates that a fairly large number of MEMS startups may be ready to start production and could use these foundry services.

Many market forecasts expect MEMS to grow at a compound annual growth rate of 17% to 20% over the next four to five years. MEMS devices can now be found in many consumer sectors like digital and projection TVs, home theaters, video games, and of course, automotive electronics (though many analysts break this area out separately). Another sector with a large MEMS penetration, medical electronics, uses millions of disposable MEMS blood-pressure sensors. Still, futurists see a much larger consumer arena involving DVD and CD players, gyros for stabilizing camcorders, and MEMS microphones and hearing aids.

One projected huge market, "information technology peripherals," is defined by the German firm Wicht Technologie Consulting (www.wtc-consult.de) as the convergence of applications of IT hardware (read/write heads and disks), computer peripherals (printers, keyboards, scanners, displays, and mice), multimedia devices (digital cameras and MPEG players), mobile phones, PDAs, and wearable computers, all interconnected by wireless local-area networks (LANs) and Bluetooth and HomeRF networks.

In a COMS 2003 presentation, Wicht cites data from the European Nexus group predicting that $39 billion of the projected $67 billion 2005 worldwide MEMS and microsystems market will be composed of IT peripherals (Fig. 1). Just one example cited is a 1-Gbyte coin-size optical disk and optical drive under development at Philips (www.philips.nl) for portable storage. This kind of product driver can have broad applications in digital cameras, mobile phones, PDAs, and portable Internet devices, with MEMS and microsystems technologies playing key roles.

MEMS device manufacturers are trying to establish a large market in toys and games as well. Analog Devices (www.analogdevices.com) and MEMSIC (www.memsic.com) have experienced limited success, as they still have to lower costs further from the approximately $2 per sensor to the roughly 50-cent range to replace mechanical switches.

MEMSIC is on that track by lowering production costs. The company reported promising talks with toy maker Hasbro (www.hasbro.com) and is already supplying sensors for a Chinese-made remote-controlled helicopter as well as handheld GPS devices sold by Thales Navigation (www.thalesnavaigation.com). MEMSIC also supplied low-cost sensors for Magic Labs' "Twighlight," a wand that casts "spells" based on specific motions. A more upscale version of this wand, Sephiral, uses MEMS sensors from Analog Devices too.

AIBO, the Sony (www.sony.com) robot dog, is one of the more notable toys using MEMS sensors, some from Analog Devices. Its sensors detect motion, pressure, heat, and angular velocity. A more sophisticated version may very well be on the market by the time this article is published. MEMS accelerometers from Analog Devices are also in Nintendo's (www.nintendo.com) Tilt 'N' Tumble game for Game Boy. Analog Devices' sensors can also be found in Microsoft's (www.microsoft.com) Freestyle Pro game controller.

There's no question that the MEMS industry has established a strong infrastructure, with a healthy and productive R&D effort. But as Roger Grace (president of Roger Grace Associates, MEMS market consultant, and president of MANCEF) cautions in his latest MEMS industry report card, not much formal market research exists to determine customer needs or price points.

One of the largest costs associated with bringing MEMS to the commercial market is device packaging. This can represent up to 80% of a MEMS device's total cost. Add in testing costs, and it can reach 90% or more. While conventional ICs may share some similar processing steps, the packaging issues are totally different for each. Consequently, companies like Amkor (www.amkor.com), Corning Intellisense (www.intellisense.com), IMEC (www.imec.be), MEMSCAP (www.memscap.com), Xanoptix (www.xanoptix.com), and Ziptronix (www.ziptronix.com) have emerged with expertise in the packaging of both conventional and MEMS ICs.

"Micro/nano systems are a new paradigm that requires different thought processes from both business and academic entities," says Robert Mehalso, president of Microtec Associates ([email protected]). "In the past, industry would give academia grants and not expect much in return. While industry does not expect academia to get involved in MEMS commercialization efforts, it looks to it to solve problems like that of packaging."

Mehalso feels that the academic world must deal with science issues as well as develop solutions to practical problems like packaging. "Engineers must have a very good understanding of materials issues, and academia needs a 'machine shop' mentality," he says.

To combat this problem, MEMS IC makers are establishing closer relationships with packaging houses and are reaching out to academic and leading research organizations. The Fraunhofer Institute (www.fraunhofer.de), a German research organization, will use SUSS MicroTec's (www.suss.de) SB6e substrate bonding equipment to lower the costs of wafer-level MEMS package processing and thus increase MEMS' marketability.

The SB6e tool was developed to enable MEMS processes to be easily transformed from the development phase to mass production. It will be used in conjunction with a flux-less, lead-free solder bonding process Fraunhofer developed for wafer-to-wafer bonding. Fraunhofer's move occurs within the context of MELODICT, a European-sponsored project focused on commercially developing RF MEMS transceiver devices for wireless communications.

Kris Baert, vice director of IMEC's Micro-systems Department in Heverlee, Belgium, says a more compact and cost-effective MEMS approach for RF MEMS is possible. He's proposing the integration of RF MEMS devices like switches and resonators with passive RF components in an MCM-D (MultiChip Module, Dielectric) module (Fig. 2).

Baert points out that conventional IC packaging and MEMS/MST packaging processes don't have the same problems. He says that the former devices are isolated from external energy forces like pressure, heat, and vibration while the latter devices are not. This makes them less likely to scale with advances in IC densities, which isn't the case with conventional packaging.

The push to commercialize RF MEMS devices drove DISCERA (www.discera.com) to manufacture its oscillators on Canadian-based DALSA's (www.dalsa.com) low-temperature, high-volume MEMS manufacturing process. DISCERA's MEMS oscillators consist of a bank of resonators that are 20 µm wide, each operating at a different frequency. They can replace multiple quartz-based and surface-acoustic-wave (SAW) devices used extensively in present cellular, GPS, wireless LAN, Bluetooth, and RFID applications.

OEMs are also becoming more innovative in packaging when using MEMS sensors. Denmark-based Grundfos A/S (www.grundfos.be), who makes pressure sensors for water pumps, uses a protective coating on the sensor consisting of amorphous layers of tantalum oxide and tantalum nitride instead of the conventional method of a steel membrane and incompressible silicone oil. In the COMS 2003 presentation "Sensors for Pumps," it reports that this simplifies packaging with no increase in cost for a much more compact package that can still operate in harsh environments at extended lifetimes (Fig. 3).

One recent development has the MEMS industry reaching out to governments worldwide to fund technology centers and clusters for investigating MEMS/nano production issues. Significant levels of MEMS production are occurring in many countries, such as India, China, Mexico, and Taiwan.

Mehalso, David Tolfree of British-based Technopreneur Ltd. ([email protected]
, and others recently proposed that the British Northwest Development Agency set up a high-tech manufacturing site in the northwest region of the U.K. It would have the necessary equipment, facilities, and manpower that will in time become an attractive site for bringing in long-needed industrial manufacturers. That large budget proposal was approved by the agency, which itself has considerable funding from the British government.

In his COMS 2003 presentation "The Pathway of Micro/Nano Commercialization," Mehalso points out that such centers will reduce the time and cost for a product's introduction into the market. According to Tolfree, who expects the proposal to take effect by about 2005, the biggest problem is getting skilled personnel for the center, of which there's a serious shortage in the United Kingdom.

During the first Pan American MEMS conference, held in Puerto Vallarta, Mexico, Sept. 19-20, MEMS industry experts met with representatives of the Mexican government. At the conference, the Mexican government announced its commitment to a national MEMS initiative by establishing a network of education and research in MEMS technology. This network cluster will form the manufacturing basis for further spinoffs of companies in MEMS and microsystems technologies.

"We are pleased with the very high interest by our Ministry of Economy and CONACyT in promoting the commercialization and education of MEMS technology," says the conference's general chairman, Ing. Guillermo Fernandez. Fernandez is also the executive director of FUMEC, the U.S.-Mexico Foundation for Science. FUMEC, a non-governmental organization endowed by the U.S. and Mexico, was established in 1992 through a bi-national agreement to promote and support collaboration and technology between the two governments. CONACyT is Mexico's National Council for Science and Technology.

Also at the Pan American MEMS conference, Alejandro Gonzales Hernandez, the general director for Training and Innovation Technology of the Mexican Economy Ministry, declared that MEMS technology was a strategic focus for his government. He said that the MEMS cluster will be the first in Mexico and will focus on MEMS packaging.

COMS 2004 will be held in Edmonton, Alberta, Canada, Aug. 29 through Sept. 2, 2004. For more information and registration, go to www.mancef.org.

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