|Silicon Foundries to Expand into MEMS Business|
|Saturday, 22 October 2011 01:08|
The microelectromechanical systems (MEMS) foundry business is a paradox that is up for grabs — and ripe for consolidation.
For some time, the MEMS foundry business has been dominated by one vendor — STMicroelectronics Inc. — followed by a steep drop in share by the likes of Texas Instruments Inc., Sony Corp. and a plethora of smaller MEMS-only foundry players.
But the balance of power could soon change as several silicon foundry vendors — such as GlobalFoundries, TowerJazz, SMIC, UMC, TSMC and X-Fab — will either enter or expand their efforts in the booming MEMS arena. Silicon foundry vendors are adding 200mm MEMS capacity, devising new MEMS-CMOS processes and moving to accelerate the sluggish development cycles.
As the semiconductor market matures, silicon foundry vendors are looking for new growth drivers and MEMS appears to be an easy market to conquer. After all, the overall MEMS market grew by 25 percent in 2010, but the MEMS foundry sector only saw 10 percent growth, according to Yole Developpement of France, meaning that the trend towards MEMS outsourcing is still in its infancy and ready for the taking.
Also look for a shakeout in the sector. “In MEMS, you will see consolidation,” said Peter Himes, vice president of marketing and strategic alliances for Sweden’s Silex Microsystems AB, the world’s largest pure-play MEMS foundry vendor.
On the other hand, the MEMS-only foundries already have the technologies in place to serve this large but fragmented market. While the silicon foundries are only talking about 3D, the MEMS foundries already offer interposers and through-silicon-via (TSV) platforms.
And MEMS is vastly different than the IC sector, where nearly every integrated device manufacturer (IDM) has ceased building fabs and embraced the foundry model. In MEMS, IDMs are still generally keeping their fabs or holding on to their fab-lite models. Some MEMS IDMs even provide foundry services.
Simply put, MEMS is a paradox. Despite the booming growth in MEMS, the business is tough and requires patience. Unlike the semiconductor arena — where a single process can run a multitude of high-volume parts — the MEMS foundry market is a custom or “one design, one process paradigm,” said Rakesh Kumar, director of the 200mm business unit at GlobalFoundries Inc., during a presentation at the recent Semicon West trade show.
The development cycles are expensive and painfully long, Kumar said. There are “no standard design rules, reusable parameterized cells and component libraries,” Kumar said.
MEMS are hot
MEMS are mechanical and electrical systems, which are built on a chip. There are various categories of MEMS, including sensors, actuators and 3D structures. In total, the MEMS market is expected to jump from $8.7 billion in 2010 to $19.6 billion by 2016, a 15 percent annual compound growth rate, according to Yole.
Amid booming growth in automotive, medical and industrial applications, pressure sensors are projected to become the largest MEMS device by 2014, according to IHS iSuppli. In consumer applications like mobile devices, “the real blockbuster is the 3-axis gyroscope, a standard MEMS device that when used in conjunction with an accelerometer and a digital compass allows for more accurate, smoother and faster motion sensing for applications such as gaming and augmented reality,” according to iSuppli.
“Beyond the 3-axis gyroscopes, accelerometers, microphones and bulk acoustic wave filters already found in tablets and smartphones, a new class of emerging MEMS sensors is stimulating growth,’’ according to iSuppli. “In this category are devices such as thermopiles, varactors, timing devices, pressure sensors for indoor navigation, radio frequency MEMS switches and actuators used for autofocus functions in high-megapixel cameras and pico projectors.”
The MEMS business is maturing as it moves from a fragmented market to fewer larger IDM suppliers. Some 21 IDM players had sales above $100 million in 2010, according to Yole.
With $204 million in sales in 2010, STMicroelectronics dominated the MEMS foundry business. The company makes inkjet printer systems on a foundry basis for Hewlett-Packard. Beyond that, the market is up for grabs. Silex was the second largest player with $37 million in sales in 2010, according to Yole. Nine MEMS foundries had revenues of about $20 million or more, according to the firm.
Yole estimated that TSMC roughly doubled its MEMS revenues last year, to jump from about $10 million to about $20 million in MEMS foundry revenues. X-Fab, TowerJazz and UMC also saw healthy growth. “These foundries may not be seeing the same big growth, but they are making a good, profitable business,” said Jean Christophe Eloy, CEO of Yole.
The silicon foundries may lack the patience to play in the MEMS game, causing them to languish or exit the business, observers said. It also could prompt the silicon foundries to buy a MEMS-only foundry to gain expertise.
In any case, the silicon foundries are expanding into MEMS. In 2010, GlobalFoundries and the Institute of Microelectronics (IME) in Singapore, announced plans to develop a MEMS-based sensor platform. GlobalFoundries has yet to officially announce its MEMS offerings.
In January, Taiwan silicon foundry giant United Microelectronics Corp. (UMC) started production of MEMS sensors. Earlier this year, TSMC rolled out a 0.11-micron MEMS-on-CMOS process.
Germany’s X-Fab Silicon Foundries AG, one of the world’s largest analog/mixed-signal foundries, has participated in the MEMS foundry business for a decade. Thomas Hartung, vice president of marketing for X-Fab, said the MEMS market has finally reached an inflection point, where many MEMS devices from both IDMs and startups are moving from the “engineering phase” towards a “steep ramp.”
“It’s a very diverse business,” Hartung said. “We expect strong growth in the next four to five years.”
For years, the German company offered MEMS foundry services on wafers up to 150mm. Last year, X-Fab expanded its foundry service to include 200mm MEMS capacity as a means to reduce production costs. The company is developing MEMS devices on 200mm wafers in combination with 0.35-micron CMOS technology.
Earlier this year, X-Fab acquired a 25.5 percent stake in MEMS foundry Itzehoe GmbH (MFI) in a move to expand its 200mm capacity. And more recently, X-Fab added IP blocks for acceleration sensors to its MEMS foundry service offerings. The accelerometer IP design blocks are said to shorten design times and reduce customer learning cycles for new product introduction.
MEMS foundry prep TSVs
Unfazed by the silicon foundries, the MEMS-only foundries said the newcomers face some challenges. Generally, the larger silicon foundries are not interested in small volume or “one or two wafer jobs,” said Aria Birang, sales and marketing specialist with Innovative Micro Technology (IMT), a MEMS foundry in Santa Barbara, Calif. Companies like IMT are more specialized and equipped to support both large and small MEMS houses, she said.
IMT only provides MEMS foundry services on 150mm wafers, but it mulling plans to add 200mm capacity. Last year, the company announced the addition of a new geometry point in its TSV roadmap. Joining the copper-filled 15 by 60 micron depth TSV configuration that has been in production for nearly three years, IMT is moving towards 50 by 250-micron copper-filled TSV for RF applications.
Sweden’s Silex has offered its TSV platform since 2006, but there is more to MEMS than just 3D technology. “The reality of MEMS is that it takes a long time to get into the business,” Himes said.
He listed several challenges in the arena. First, the product development cycles are long — sometimes three to four years — because of the proprietary nature of the processes. Second, the investments are relatively high. Third, the product is more of a custom device based on a single process. And finally, the volumes are sometimes low.
Unlike the digital IC world, where there is a plethora of EDA tools, IP and manufacturing tricks, the MEMS world lacks a similar ecosystem, he said. To speed up MEMS designs, Silex has recently licensed its so-called Sil-Via platform, a TSV packaging technology, to Nanoshift, a MEMS design and R&D firm.
Silex has a similar alliance with A.M. Fitzgerald & Associates, a MEMS design firm. “Through Silex Sil-Via license agreements, Silex continues to execute on its strategy to make it easier for customers to conceive of complex MEMS devices, develop prototypes and then rapidly transition those designs into volume production,” Himes said.
Silex offers both 150mm and 200mm MEMS foundry capacity. Its TSV technology is said to be a sub-50-micron pitch for through wafer connections in up to 600-micron thick substrates. The “via first” approach enables building CMOS sensors on top of via substrates, thereby facilitating the integration of MEMS and CMOS.
The company’s TSV process begins with the formation of the trench using a dry reactive ion etch process. Typical trench width is 10 to 20 micron. Then, the wafer is subject to a high temperature filling of the trenches by a dielectric material. Finally, a CMP process is applied to the backside of the wafer.
Despite the challenges and technology, MEMS is still the place to be. “Our business is growing quite strong,” Himes said. “People talk about the explosiveness of MEMS. But most don’t recognize that you are building tens or hundreds of wafers” and not thousands or more.