MEMS without cleanrooms

Mark A. DeSorbo

BURBANK, CA—Saying it will revolutionize the micro-machining industry, a toolmaker has unveiled a micro electro mechanical systems (MEMS) fabrication process that eliminates the need for cleanrooms.

Deemed “EFAB,” MEMGen Corp.'s electrochemical fabrication uses a variety of metals and materials, aside from silicon, within a controlled space that sounds a lot like a minienvironment or an isolator.

The bulk of today's MEMS devices are manufactured in the traditional semiconductor paradigm, which calls for cleanrooms that range from ISO Class 5 to ISO Class 7, says Chris Bang, MEMGen's applications engineering manager.

“We've come up with a completely new process technology,” Bang says. “This is a simplified process. We can do it in a self-contained machine that can sit on the floor of a warehouse. It's a little bigger than a refrigerator and looks about the same size as other pieces of semiconductor equipment.”

Neither Bang nor Dan Feinberg, director of sales and marketing, would provide details on cleanliness levels or filtration mediums of the EFAB machine.

According to MEMGen's Web site,, the EFAB process is “fully integrated and performed in a single machine (essentially, a cluster tool) with its own controlled environment. The EFAB machine can operate on an ordinary factory floor, and since the manufactured devices are encased in protective sacrificial material they can be handled and transported normally after fabrication.”

“Contamination control is certainly an issue for our machine, so it has what it needs to produce that environment,” Feinberg adds. “There are just some things we cannot talk about.”

MEMGen, however, touts EFAB's capability of high-speed, automatic fabrication of three-dimensional micromachines.

According to the company, the EFAB machine performs an electrochemical process that cuts fabrication time. A metal substrate is inserted into the machine where hundreds of layers of material can be deposited. The substrate is then etched and polished to completion.

The EFAB process can use 3-D CAD data, allowing parts to be designed by any engineer, thus eliminating the need for MEMS or semiconductor manufacturing expertise.

MEMGen Corp. says its EFAB allows optics engineers to design devices using conventional 3-D CAD without having to become an expert. The optics engineer is free to design optical systems in three dimensions, overcoming what MEMGen calls “the complexity and planar limitations of conventional silicon bulk and surface micromachining.”
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“We leave the product to the people who have the expertise rather than the process engineers,” Bang says. “That makes it easier for others to get involved with this technology.”

In addition to MEMS devices, EFAB can be used to make other optical components, like micro-mirror devices, optical attenuators and fiber alignment and packaging aids. It can also be used to manufacture radio frequency (RF) switches and relays, inductors, transmission lines, filters, antennas and transformers.

“EFAB can build a wide range of micromechanical and microelectrical devices, but does not build transistors, diodes or similar devices that exploit semiconductor device physics,” according to the company Web site. “However, the EFAB process is compatible with integrated circuit (IC) processing and can be used to build micromechanical devices and electronic components such as capacitors and inductors that can either be built directly on semiconductor wafers and ICs, or readily integrated with ICs using standard packaging technologies.”

The EFAB machine may also appeal to the medical device industry as well. Surgical tools, fluid-dispensing heads and drug delivery and implant devices can also be manufactured within an EFAB machine.

Bang and Feinberg say EFAB's manufacturing versatility is complimented with cost-effective elimination of cleanrooms and related apparel.

“We're not saying cleanrooms are not useful,” Bang interjects.

Instead, Bang and Feinberg like to say MEMGen is bridging the gap between the macro world and the micro world. That does not mean MEMGen is gearing up to mass-produce and sell its EFAB machines.

“We're keeping the technology in-house and working with strategic partners,” Feinberg says, declining to name names.

For now the company will concentrate on contract manufacturing within a 22,000-square-foot-facility.

“We have what we call a foundry room with a number of EFAB machines in it,” Feinberg says. “We are able to ramp from prototype all the way to high-volume production.”

Ramping up production, Bang adds, is just a matter of adding another machine, and any changes that need to be made can be done right through the software. “And it can all be done on a warehouse or shop floor and no one has to wear a bunny suit,” he says. “Our goal is to allow the world to downsize mechanical things.”

Robert Spector, a member of the CleanRooms Editorial Advisory Board, says manufacturing without the cleanroom is nothing new and can be done.

In fact, Ball Semiconductor Inc. (Allen, TX), he says, does not use cleanrooms to make its spherical semiconductors.

“There's got to be cleanliness somewhere in the process,” Spector says. “Everything is application-specific, but if the product functions without the need for a cleanroom environment for manufacturing, then that's a savings in equipment costs and a cut in your overhead. Then again, a process without cleanrooms just may be functional for a specific device.”


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