An Introduction to mems (Micro-electromechanical Systems)

An Introduction to MEMS 

 

 

Prime Faraday Technology Watch – January 2002 

15

 

 

 

Product Types 

1996 

Units 

(millions) 

$ 

(millions)  

2002 Units 

(millions)  

$ (millions)  

Drug delivery systems 

1 

10 

100 

1000 

Optical switches 

1 

50 

40 

1000 

Lab on ship 

0 

0 

100 

1000 

Magneto optical heads 

0.01 

1 

100 

500 

Projection valves 

0.1 

10 

1 

300 

Coil on chip 

20 

10 

600 

100 

Micro relays 

 

0.1 

50 

100 

Micromotors 0.1 

5 

2 

80 

Inclinometers 1 

10 

20 

70 

Injection nozzles 

10 

10 

30 

30 

Anti-collision sensors 

0.01 

0.5 

2 

20 

Electronic noses 

0.001 

0.1 

0.05 

5 

TOTAL__33__$107__1045__$4,205'>TOTAL 

33 

$107 

1045 

$4,205 

 

 

A more recent market study by NEXUS/Roger Grace Associates, shown in Table 5, estimated 

the M

3

 market to be $14.2 billion in 2000, increasing to $30.4 billion by 2004.  This 

corresponds to a compounded annual growth rate (CAGR) of 21%.  Telecommunications is 

forecast to be the major growth area, comprised of both optical MEMS and RF MEMS-based 

devices. 

 

 

Application Sector 

2000 

2004 

CAGR(%) 

IT/Peripheral 

$ 8,700 

$13,400 

11.5 

Medical/Biochemical 

2,400 

7,400 

32.5 

Industrial/Automation 

1,190 

1,850 

11.6 

Telecommunications 

130 

3,650 

128.1 

Automotive 

1,260 

2,350 

16.9 

Environmental Monitoring 

520 

1,750 

35.4 

TOTAL 

$14,200 

$30,400 

21.0% 

 

 

2.6  Miniaturization Issues 

 

As previously stated, MEMS is not about miniaturization; it is a manufacturing technology 

used to create tiny integrated microdevices and systems using IC batch fabrication techniques.  

Similarly, miniaturization is not just about shrinking down existing devices (although there 

have been some classic examples, namely the DENSO Micro-Car as shown in Figure 14); it’s 

about completely rethinking the structure of a microsystem. 

 

Table 4.  Worldwide M

3

 market size in 1996 and 2002 for emerging MEMS product types 

in $US millions [23]. 

Table 5.  Worldwide shipment of M

3

 products by application sector for 

2000-2004 in $US millions [23,26]. 

An Introduction to MEMS 

 

 

Prime Faraday Technology Watch – January 2002 

16

 

 

 

 

In order to manufacture a successful MEMS device basic physics and operating principles 

including scaling laws need to be fully understood and appreciated at both a macro and 

microlevel.  Sometimes no advantages in terms of performance, size/weight, reliability and 

cost can be gained with a MEMS device.  Increased surface area (S) to volume (V) ratios at 

microscales have both considerable advantages and disadvantages (Figure 15). 

 

 

Figure 15.  Effect of miniaturization on surface area and volume. 

 

Some of these microlevel issues include: 

 

•

  Friction is greater than inertia.  Capillary, electrostatic and atomic forces as well as 

stiction at a micro-level can be significant. 

 

•

  Heat dissipation is greater than heat storage and consequently thermal transport 

properties could be a problem or, conversely, a great benefit. 

 

•

  Fluidic or mass transport properties are extremely important.  Tiny flow spaces are 

prone to blockages but can conversely regulate fluid movement. 

 

•

  Material properties (Young’s modulus, Poisson’s ratio, grain structure) and 

mechanical theory (residual stress, wear and fatigue etc.) may be size dependent. 

 

•

  Integration with on-chip circuitry is complex and device/domain specific.  Lab-on-a-

chip systems components may not scale down comparably. 

 

•

  Miniature device packaging and testing is not straightforward.  Certain MEMS sensors 

require environmental access as well as protection from other external influences.  

Testing is not rapid and is expensive in comparison with conventional IC devices. 

 

•

  Cost – for the success of a MEMS device, it needs to leverage its IC batch fabrication 

resources and be mass-produced.  Hence mass-market drivers must be found to 

generate the high volume production.  

Figure 14.  The DENSO Micro-Car is a miniature version of Toyota’s first passenger car.  Fabricated 

using MEMS, at 1/1000

th

 the size of the original, it consists of a 0.67 mm magnetic-type working 

motor and when supplied with 3 V 20 mA of alternating current through a 18 µm copper wire, the 

engine runs at 600 rpm equivalent to 5-6 mm/s [27]. 

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