Baolab Claims CMOS MEMS Breakthrough – 2010-03-08 07:07:00 | Semiconductor International.
David Lammers, News Editor — Semiconductor International, 3/8/2010
Baolab Microsystems, S.L. (Barcelona, Spain) said it has developed etching techniques that allow MEMS devices to be built within the metallization layers of standard CMOS wafers, with significant cost savings over today’s MEMS manufacturing techniques.
Dave Doyle, CEO, BaolabCEO David Doyle said over the past decade the company has perfected a way to “repeatably and reliably etch away the layers of inter metal dielectrics.” The approach uses vapor hydrofluoric (HF) etching, Doyle said, adding that “while we can’t detail how we do it, it avoids any uncontrolled reactions by altering the gas flow, ending up with water as a byproduct.”
Baolab founder and CTO Josep Montanya worked on the MEMS approach while gaining his doctorate from UPC-Barcelona Tech, near Barcelona, which has a strong MEMS program.
Doyle said some MEMS companies that claim they use a CMOS process are building the MEMS device on top of a standard CMOS wafer. A MEMS-on-CMOS process adds cost. Baolab claims that it can build MEMS devices within the thin aluminum interconnect layers.
The strategy is to demonstrate several high-volume MEMS products used in RF switches, accelerometers, sensors and other products. The company has developed products on a 180 nm process with four or more metal layers, with minimum feature sizes as small as 200 nm. The process, called NanoEMS MEMS, integrates the MEMS function with the active CMOS control circuitry.
The NanoEMS process is capable of MEMS devices with 200 nm feature sizes. (Source: Baolab)
While many companies have tried to build MEMS devices within a CMOS wafer, those attempts have failed, largely due to reliability problems. “Nobody has been able to do it successfully. Then, when companies build the MEMS on top of the CMOS wafer, they don’t get the cost advantages. They end up using a special process flow,” Doyle said.
Baolab has developed prototypes, and plans to deliver engineering samples to customers by the end of the third quarter. It has worked with smaller foundries to develop its manufacturing flow, and has relationships with two of the largest Asian foundries for high-volume manufacturing. While startups have a difficult time getting qualified by the major handset manufacturers, Baolab’s business plan is to supply the module manufacturers that supply the cellphone manufacturers, for example, he said.
“We believe we will have a significant cost advantage when we get to economies of scale,” he said. “This is one tweak to a standard CMOS flow — one 30-second gas flow change.”
While some companies build MEMS on top of a standard CMOS wafer, Baolab builds MEMS within the metallization layers.