Micro-Electronic Mechanical Systems (MEMS): How is Technology Change Creating New Opportunities in Them?

How is Technological Change Creating New Opportunities in Micro-Electronic

Mechanical Systems (MEMS) 5th Session of MT5009

A/Prof Jeffrey Funk

Division of Engineering and Technology Management

National University of Singapore

Sources: Clark Ngyuen’s lectures at UC Berkeley and others

Objectives

• What has and is driving improvements in cost and performance of MEMS?

• Can we use such information to

– identify new types of MEMS and applications for them?

– analyze potential for improvements in these new technologies?

– compare new and old technologies now and in future?

– better understand when the new technologies might become technically and economically feasible?

– analyze the opportunities created by these new technologies?

– understand technology change in general

Session Technology

1 Objectives and overview of course

2 Four methods of achieving improvements in performance and cost: 1)

improving efficiency; 2) radical new processes; 3) geometric scaling; 4)

improvements in “key” components (e.g., ICs)

3 Semiconductors, ICs, new forms of transistors, electronic systems

4 Bio-electronics, tissue engineering, and health care

5 MEMS, nano-technology and programmable matter

6 Telecommunications and Internet

7 Human-computer interfaces, virtual and augmented reality

8 Lighting and displays

9 Energy and transportation

10 Solar cells and wind turbines

This is Part of the Fifth Session in MT5009

Outline

• What is MEMS and what are the applications?

• MEMS and Moore’s Law (Benefits of scaling)

• Example of MEMS for filters and other components for mobile phone chips

• Example of micro-gas analyzers

• Example of MEMS for Ink Jet Printer

• Design tools for MEMS

Increasingly Detailed View of a Micro-Engine Source: http://www.memx.com/

Micro-engine Gear Train Multi-level springs that that are part of Micro-Engine

Side view of springs

http://www.memx.com/images/transmission.jpg

http://www.memx.com/images/gear-train.jpg

http://www.memx.com/images/surface-mems.jpg

http://www.memx.com/images/multi-level-mems.jpg

Ratchet Mechanism Actuator Torsional Acutator Early Optical Switch Clutch Mechanism Anti-reverse mechanism

http://www.memx.com/

http://www.memx.com/images/mems-thermal-actuator-pic.gif

http://www.memx.com/images/mirror.jpg

http://www.memx.com/images/torsional-actuator.jpg

http://www.memx.com/images/clutch.jpg

http://www.memx.com/images/mems-gears.jpg

Accelerometer less detail more detail Inertial Sensor (includes accelerometer and gyroscope) less detail more detail

Another List of Applications (1)

• Accelerometer – cause airbag deployment in automobile collisions – control handheld games (Wii) or mobile phones – in PCs to stop hard disk head when free-fall is detected – Seismic imaging – Infrastructure monitoring (HP, sensing as a service, $150 B

USD)

• Gyroscopes (includes accelerometer and inertial sensor) – maintain orientation in mobile phones, automobiles

• Pressure sensors – car tires, manifold, blood pressure

• Fluid acceleration – micro-cooling of ICs, including bio-electronic ICs

Another List of Applications (2)

• Inkjet printing

– piezoelectrics or thermal bubble ejection to deposit ink on paper

• Optical switching technology (Photonics)

• Micro-mirrors

– For various types of displays

– Add a projector to your mobile phone

• Interferometric modulator display

– Used to create various colors in a display

Source: http://www.isuppli.com/MEMS-and-Sensors/MarketWatch/Pages/MEMS-Market-Rebounds-in-2010-Following-Two-Year-Decline.aspx

Outline


• MEMS and Moore’s Law





Figure 2. Declining Feature Size

0.001

0.01

0.1

1

10

100

1960 1965 1970 1975 1980 1985 1990 1995 2000

Year

Mic

rom

ete

rs (

Mic

rons)

Gate Oxide

Thickness

Junction Depth

Feature length

Source: (O'Neil, 2003)

In 1990s emphasis on both mechanical components and transistors

Source: Clark Ngyuen, August and September 2011 Berkeley lectures

Accelerometer


Limitations of Scaling for Accelerometers

• Since displacement is proportional to size of mass in accelerometer – Smaller mass leads to weaker sensitivity to

displacement – Thus smaller features (e.g., springs) are bad

• Solution for MEMS-based accelerometers – Integrate transistors with MEMS device to

compensate for the poor sensitivity of MEMS-based accelerometers

– put transistors close to the MEMS device in order to reduce parasitic capacitance

• This led to pessimistic view towards MEMS


Nevertheless, improvements were made to accelerometers in the form of smaller size chips. Source: Trends and frontiers of MEMS, Wen H. Ko; Cs: sensing capacitance

But then other Applications Began to Emerge

• Gyroscopes

• Micro-fluidics

• Digital mirror device

• Optical switches

• These applications benefited from smaller sizes! Emphasis changed – from “adding transistors” to “reducing feature size”

– from “integration of transistors and mechanical functions” to chips with only mechanical functions/devices

Source: Ngyuen, Berkeley lecture



Benefits of Size Reduction: MEMS (2)

• Feature sizes are currently much larger than those on ICs – MEMS: around or less than one micron

– ICs: 22 nanometers (0.02 microns)

• Partly because – devices are different (e.g., much overlap of layers)

– processes (e.g., wet vs. plasma etching) are slightly different……

• The improvements and thus the opportunities are probably limitless – We just need to find the applications that will benefit from

smaller sizes and to develop those applications

Source: Nyugen’s Berkeley lectures and http://www.boucherlensch.com/bla/IMG/pdf/BLA_MEMS_Q4_010.pdf


Accelerometer

Smaller feature sizes also lead to more mechanical & electronic components

Outline








Mass is function of length (L), width (W), and h (height); Q is amplification factor, V is voltage; d is distance between bottom of beam and underlying material

Scaling of Mechanical Resonator

• Operates slightly different from guitar string • Calculations show that frequency rises as 1/L2

• Replacing anchored beam with free-free beam and reducing L (length) to 2 microns, W and H to nano-dimensions, causes frequency to rise to above 1 GHz – Inexpensive mechanical resonators can replace electrical

filters – Which also enables the use of multiple filters and thus

communication at many frequency bands (and thus cognitive radio)

• There is no theoretical limit to reducing sizes and thus increasing frequencies

Source: EE C245/ME C218: Introduction to MEMS, Lecture 2m: Benefits of Scaling I

Making Resonators with semiconductor processes/equipment


But actually calculations show that disks scale better than do beams or springs

(t = inner radius)


Build a filter with multiple disks

Source: Clark Ngyuen, August and September 2011 Berkeley lectures; RF BPF: radio frequency bypass filter

Source: Clark Ngyuen, August and September 2011 Berkeley lectures RF = radio frequency; SAW = surface acoustic wave: VCO: voltage controlled oscillators




Another application for MEMs in phones, GPS, and other devices

Outline







Source: Clark Ngyuen, August and September 2011 Berkeley lectures; ppb: parts per billion; ppt: parts per trillion


Chromatography is collective term for set of laboratory techniques for separation of mixtures


(1)


(2)

Outline







Outline







MEMS design tools

• Create individual 2-D layers, stack them on top of each other, and create complex 3-D devices

• Design tools (e.g., 3D process simulator) enable designers to visualize their creations before they are built • Similar to CAD tools for ICs • Improvements in ICs lead to better CAD tools

• Design libraries have been developed which enable designers to create complex designs from multiple standard components – Similar to standard cell libraries with ICs

Source: http://www.memx.com/design_tools.htm

Design Library Process simulator

Conclusions (1)

• There appears to be many benefits from

– reducing the scale of features in MEMS

– adding more transistors to MEMS

• These benefits depend on the application and the way in which the application is implemented

• These benefits are causing many types of MEMS to experience exponential improvements in cost and performance

• This degree of change will probably create many types of entrepreneurial opportunities

Conclusions (2)

• For your presentations,

– How will an existing new application diffuse to a broader market as this scaling proceeds?

– When will a new application become technically and economically feasible as this scaling proceeds?

– To what extent will this create entrepreneurial opportunities and what kinds of opportunities?

Business

Micro-Electronic Mechanical Systems (MEMS): How is Technology Change Creating New Opportunities in Them?