Micro Electro Mechanical Systems

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Micro-Electro-MechanicalSystems

• An Introduction to MEMS Technology
• Paul Bowling
• Texas Tech University

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Huh?
What do all those words mean?!
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Lets Define

• Micro Really Small
• HOW SMALL??? One millionth of a meter!
• Width of Human Hair (100 micro-meters)
• __________________________________________________
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• Size of MEMS features (1 micro-meter)

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Lets Define

• Electro Uses electricity
• Mechanical Involves motion
• How does it do both?
• Uses electricity to cause motion!
• Uses motion to change electricity!

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Lets Define

• System - A group of things acting together as a
  whole
• Some MEMS devices have millions of parts acting
  together!

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So Lets See It!
Alright, I think Im getting it. You say theyre
small, huh? So show me!
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Examples

• MEMS motor
• The straight arms push the gear around
• The arms are controlled by electricity

That spins? Cool!
1 micro-meter
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Examples

• A gear can turn another gear
• Just build it right next door!

This looks familiar! Ive got gears on my bike!
Theyre a lot bigger, though
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Examples

• These start the movement
• Electricity causes them to move!
• The two sides are attracted to each other when
  they have different voltages

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Voltage
0 Volts
Attractive Force!
9 Volts
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Wow, thats neat! But how in the world do you
build something THAT small??
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Layers is the key!

• Everything is built one layer at a time
• First, a layer of material is formed on top of a
  silicon wafer this will be removed later

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Building a MEMS Device

• Second, that layer is cut to the right shape
  using a process called photolithography

Mask
Put on light-sensitive layer
Expose layer to light using mask
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Building a MEMS Device
Hole in light-sensitive layer
Now the lower layer is cut to size
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Building a MEMS Device

• Third, a layer of metal is put down on top of the
  removable layer

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Building a MEMS Device

• Now, we cut the metal the same way that we cut
  the removable layer

Light sensitive material
Cut away the metal not covered
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Building a MEMS Device

• Last, we take off everything except the metal,
  and there we have it!

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Building a MEMS Device

• More layers can be added in the same way!
• With more layers, the little pieces can be made
  to move, or bend, or just stay put!
• Some devices put over 5 layers of metal!
• Lots of moving parts!
• Something that complex has layers like this

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Now I know everything! So where do I get my
hands on one?
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Where are they?

• MEMS devices are everywhere!
• Theyre in stuff people use every day!
• Stuff like Cars and TVs

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A Cool Example

• A lot of new TV sets use a cool MEMS device
• Its called DLP, and its made by Texas
  Instruments, Inc.
• They made a bunch of tiny mirrors that swivel
  back and forth
• The mirrors reflect light onto the TV screen to
  make a pretty picture!

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DLP
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DLP
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Conclusion

• MEMS is everywhere, and its really useful!
• Its a growing technology, and people like YOU
  can be involved in making awesome new devices and
  applications for them