An Introduction to mems (Micro-electromechanical Systems)

Despite the many similarities between IC and MEMS fabrication, MEMS makers, or 

foundries, are still in their adolescence.  The widening variety and increasing complexity of 

MEMS products make the MEMS foundry business extremely problematic.  Although the 

fabrication technology is similar, the technology is on a different scale.  MEMS are 3D 

products in comparison to the 2D level of IC’s.  Furthermore, unlike a standard IC foundry, 

which performs one or two standard processes, a MEMS foundry performs a wide variety of 

processes.  

From an economic standpoint MEMS foundries share a common characteristic with 

manufacturing.  This is because there is an enormous economy of scale as MEMS foundries 

can leverage the cumulative volume from multiple products from multiple companies to 

achieve high equipment utilization rates.  The most important difference though is that 

MEMS produces a mechanical structure that moves and that is significantly more complex 

and sensitive than traditional ‘stationery’ IC structures. 

Expansion of the MEMS market has been restricted by the need for specialized MEMS 

investment has been limited to only a few MEMS foundries.  A couple of years ago Cronos 

Integrated Microsystems of North Carolina was seen as the leading MEMS foundry in the 

field.  A spin-off from MCNC and sponsored heavily by DARPA, it developed MUMPS, 

offering low-cost manufacturing solutions for prototype and small-series MEMS applications.  

Other pioneering foundries that were able to leverage the large scale investment already made 

in silicon semiconductor fabrication include the Metal Oxide Implementation Service 

(MOSIS), operated by the Information Sciences Institute at University of Southern California; 

and Sandia National Laboratories, USA, with their SUMMiT technology.  Smaller original 

foundries still exist but in technology specific areas: MEMSCAP (France) – IC based; 

SensorNor (Norway) – bulk micromachining and fusion bonding; GEMAC (Germany) – bulk 

micromachining; and Bosch (Germany) – DRIE process.  But of these labs, none are able to 

handle mass production, certainly on the scale usually associated with the IC chip industry.  

The lack of market demand for MEMS devices is one of the factors holding the technology 

back; the devices can not be manufactured in numbers high enough to bring the price of 

MEMS chips down to the point where they make economic sense. 

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