Silicon Programming--Introduction to MEMS 1 Introduction to MEMS; energy domains; mechanical and fluidic devices

Silicon Programming--Introduction to MEMS

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Introduction to MEMS;

energy domains; mechanical and fluidic devices


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MEMS (Microelectromechanical systems)

(Other commonly used terms: Microsystems (Europe); Microfluidics;Mechatronics (Japan) )

All these terms refer to "systems" incorporating electrical elements and elements from other domains into a "chip" or "integrated circuit". Both miniaturization and integration are usually implied.

Another term commonly used is "SOC", which stands for "system on a chip".


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Motivations for MEMS:

-----space (area) savings

-----power reduction (can we use batteries?)

-----portability (reduced weight / power)

-----reliability--because of integration

-----economic savings--"mass produce" elements as VLSI chips are

currently produced

-----application of well-understood VLSI processing techniques to other domains


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Application areas (a sampling)--

-----automotive systems

-----environmental control / monitoring

-----health care

-----defense systems

----- automated manufacturing

Example applications (see, e.g., Analog Devices website, www.analog.com)::

--airbags: change in acceleration (force) is translated into signal to deploy airbag --navigation and stabilization: micro gyroscopes provide a frame of reference in navigation and stabilization systems in cars, planes, etc.--”lab on a chip”: biological / chemical procedures can be carried out on one integrated chip (Lab on a Chip journal: http://www.rsc.org/is/journals/current/loc/locpub.htm)


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Area is INHERENTLY MULTIDISCIPLINARY (based on today's "disciplines")

How old is this area? (~ 30 years)

basic reference:K. Petersen, Silicon as a mechanical material, IEEE Proceedings 70 (5), May 1982, 420-457.


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Basic idea: IC's perform (electronic) calculations extremely well; I/O is NOT generally in the electrical domain--how can I/O elements (“sensors” and “actuators”, or "transducers")be integrated?


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Energy Domains:

1. thermal--temperature, heat, heat flow, etc.

2. mechanical--force, pressure, ve;ocity, acceleration, position, etc.

3. chemical--concentration, material composition, reaction rate, etc.

4. magnetic--magnetic field intensity, flux density, magnetization, etc.

5. radiant--intensity, wavelength, polarizaion, phase, etc.

6. electrical--voltage, current, charge, etc.


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Relation to IC's:

Typical IC is built up of "layers" of material. These layers can be used to make other devices, e.g., cantilever beams for sensing and actuating

Techniques for "machining" are those used in IC fabrication--how

can they be used / modified to make devices usable in other domains?


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Devices are generally divided into two classes according to processing required:

a. "surface micromachining" (2.5D devices)

uses “layers”

b. "bulk micromachining"

(true 3D devices)


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examples:

beams

cantilever beams

membranes

ducts

motors, movable partshttp://www.sfu.ca/immr/projects/ensc494-01/acoppin/designs.html


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How can MEMS development make use of well-understood IC CAD capabilities?What extensions are needed for CAD for MEMS?

Recall:

1. Predicting IC performance requires input from fabrication, design, and environment.

2. Tools for incorporating information from each of these domainsare necessary for "rapid prototyping" which make manyIC designs economically feasible.


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Comparisons of Mechanical Properties (Petersen)Property Si SiO2 Steel Al

Yield(1010 dyne/cm2) 7.0 8.4 4.2 0.17

Hardness(kg/mm2) 850 820 1500 130

Young's mod(1012dyne/cm2) 1.9 0.73 4.9 0.7

Density(gr/cm3) 2.3 2.5 7.9 2.7

Therm. cond(W/cmoC) 1.57 .014 0.97 2.36

Thermal exp(10-6/oC) 2.33 0.55 12 25


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Tasks: Specify-Design-Simulate-Fab-Test-Maintain=====================================================================================LEVELS|| VIEWS || Behavioral Structural Physical=====================================================================================4 || Specifications, CPUs,Memory, Partitions || Systems Switches, Complex || MEMS------------------------------------------------------------------------------------------------------------------------------------------------3 || Algorithms Data Structures Clusters------------------------------------------------------------------------------------------------------------------------------------------------2 || Register Transfers ALUs, Registers, Floorplans || Electromechanical || Components----------------------------------------------------------------------------------------------------------------------------------------------- 1 || Boolean Equations,

Gates, Flip-flops, Cells, || FSMs, Mechanical Sensors, Actuators Modules || Behavior -----------------------------------------------------------------------------------------------------------------------------------------------0 || Transfer Functions Transistors, Wires, Layout || Contacts, Vias, Geometry || Beams, Membranes, || Holes, Grooves, || Joints====================================================================================

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Silicon Programming--Introduction to MEMS 1 Introduction to MEMS; energy domains; mechanical and fluidic devices