18
COVER STORY
are equally important to develop accurate MEMS devices while become viable thanks to the micro scale. As foundry companies’
achieving highest yields possible ensuring a better return on volumes increase, their competitiveness is strengthened compared
investment and improved profitability. to product manufacturers with captive MEMS production. Silex
believes that there is considerable potential for foundries to
Profitability is another area the company has had to find the increase their volumes and gain market share and the company
right balance. Starting a foundry at a relatively early stage of have begun expanding their manufacturing capacity with the
the MEMS industry was a great risk but Silex has steadily introduction of a state of the art 8” MEMS facility.
grown and the company’s operations have shown a profit since
the end of 2006 and they are very optimistic that this will Silex estimates that the existing 6” manufacturing plant will be
continue to be the case. In 2007, Silex increased sales by 77 able to accommodate production volumes until 2009. The 8” fab
percent to SEK 167.1 million (USD 27.2 million), with is being built adjacent to the current plant. By introducing 8”
operating profit improving to SEK 11.3 million (USD 1.8 wafers Silex will be able to introduce high volume efficient tool
million). Despite the differences between MEMS and sets. The company will be able to offer wafer level integration of
semiconductor manufacturing, Silex happily acknowledges that mainstream CMOS with the increased wafer size. The improved
their business model is based on the successful CMOS based scale is not just about number of die per wafer but the improved
foundries in how they attract customers and develop propriety usage of the wafer surface. You can fit nine 1x3 chips on a 6”
processes. The company has built their customer base with a mix but up to 21on an 8” wafer improving manufacturing large size
of high and low volume customers enabling Silex to add MEMS. The technology and manufacturing equipment is well
manufacturing capacity based on customer needs and successes. tried and proven in the semiconductor industry providing another
benefit to the MEMS industry from the semiconductor industry.
The company has issued new shares worth SEK 150 million
(USD 25 million) to fund the expansion. The equipment list is
not yet disclosed but the company has stated that the upcoming
purchases will constitute unparalleled MEMS capability. The
new issue is being subscribed to by Priveq Investment and
Northzone, both thereby becoming new owners in Silex.
CapMan, currently the company’s principal owner, is also
participating in the new share issue.
Despite the learning curves contributed by the semiconductor
Schematic cross section of via substrate features. industry there are again major differences in facility
requirements between MEMS and CMOS. If you look at fab
Today there is a solid customer base with more than 70 infrastructure in terms of clean room and toolset a CMOS
customers, which is large for this industry. The company foundry has more stringent rules and requirements when it
manufactures MEMS products in volumes for ten of these comes to particle requirements and containment of
customers. This broad customer base gives Silex the potential for contamination. These requirements may pose some barriers as
a major increase in volume production. Silex estimates that opposed to the more versatile approach required for true MEMS
around half of the 60 or so customers at the development phase processing. The stringent requirements required by the CMOS
today will require larger volumes in the near future. processing also come at a cost and constitute unnecessary
overheads in the eventual pricing of MEMS parts.
An issue that MEMS pure players feel is misunderstood is the
relative size of the business between the two sectors. A number Discovering MEMS process for CMOS
of CMOS foundries have recently announced intentions to enter Having used CMOS based foundries as the benchmark for
the MEMS business and there is a perception that there is a development, Silex has followed another trend of the IC
similar sized industry waiting. This may become true in terms of foundries and is continuously working on developing proprietary
device units but is vastly different from wafer output. A large MEMS foundry processes, leveraging on intellectual property
pure play CMOS foundry manufactures close to the order of 10 and know how to complement the foundry manufacturing offer.
Million 8” wafer equivalent per year whereas the MEMS This development is as essential to the company’s future as the
foundry will be manufacturing wafer volume equivalents that are expansion of manufacturing capability. In the IC foundry world
almost 1000 times smaller. If you include the number of average four companies control around 85% of the market and all have
mask layers exposed per wafer, the difference is more dramatic proprietary processes that they also licence and develop an
as a MEMS process in general will have much fewer masks per important company revenue stream for the future.
wafer. There is a potential that large CMOS foundries that are
announcing their entry into the MEMS foundry business may When the pros and cons of MEMS technology are debated in
have overestimated the available wafer volumes in MEMS. general, the argument brought forth is that the main hurdles
relating to commercial implementation are packaging and
Expanding capabilities interconnect. Silex realised this early on and began work on a
At present Silex Microsystems offers MEMS foundry wafer level packaging solution with proprietary processes. On the
manufacturing services in a fully equipped 1500 m
2
clean room way they discovered that the solution they developed had more
6” wafer fab. The company has always understood the need to applications than imagined.
expand slightly ahead of the industry needs so they can be
prepared as their customers reach high volume capacities. Via technologies are not a brand new concept in the MEMS
Utilisation of MEMS chips is growing steadily as companies and community but have so far had modest success in terms of
industries identify systems that can advantageously be commercial viability. To be more precise, the various approaches
accommodated on a microchip and discover new applications have been struggling to a large extent with inherent
www.euroasiasemiconductor.com October 2008
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