What is MEMS What is MEMS Technology?Technology?

What is MEMS ?What is MEMS ?

• Micro Electro Mechanical Systems– micro scale dimensions (1mm = 1000 microns)– electrical and mechanical features– systems (features combined to perform a function)

• MEMS fabrication techniques– Originally used IC (computer chip) fabrication techniques

and materials– More MEMS-specific fabrication techniques and materials

are now in use

• MEMS is an enabling technology– Smaller device size– Batch processing for low cost,

uniform production– Distributed device placement– More precise sensing

4000 die per 6 inch wafer

Why is MEMS useful?Why is MEMS useful?

Sensors and Actuators -two classes of MEMS

–Sensors - measure the environment

SMALL => interfere less with the environment it is measuring

SMALL => redundancy, batch fabricated, …

–Actuators - perform work on the environment

SMALL => small motion but very precise

SMALL => can be placed in small spaces

How are MEMS made?How are MEMS made?

• Surface Micromachining - additive process (2-D)– Create device by adding materials on top of a wafer – Easily mixed with IC fabrication techniques– Limited to film thickness less than 4 microns

(human hair 50-75 microns, IC gate ~ 0.15 microns)

– Typically used for high volume, low precision, low cost devices

• Bulk Micromachining - subtractive process (3-D)–Create device by etching material out of a wafer–Distinct processes and materials from IC

fabrication–Flexible for design of diverse device features

sizes–Advantageous for high precision

sensors/actuators