ALPHABOOST™THE NEXT GENERATION OF

ULTRA-CLEAN AIR IONIZATION

Transforming Technologies Presents

Outline

Microcontamination, Electrostatics and High Tech Manufacturing

Corona Ionizers and their Contamination Mechanisms collide with the 25nm node

Alphaboost® The Advantages of Corona without the Tradeoffs

Summary

Micro-Contamination in High Technology Manufacturing

Particle attraction & bonding to

charged surfaces

Damage to product

Robotic lockup

Effects of Static Charge on High Technology Manufacturing

5

Contamination Study

Wafer at 0 Vclass 1 mini environment for 6 weeks

Wafer at 2000 Vclass 1 mini environment for 6 weeks

200 mm wafer in a Class 1 Mini-Environment

Data from Frank Curran, MS thesis, "The Effects of Static Charge on Silicon Wafers in the Semiconductor Industry," The Engineering Council of England, Nov. 1997

A Particle Contamination Study

Electrostatic Attraction Defeated by Mini-Environment Ionizers

“Implementing a Static Control Program to Increase the Efficiency of Wet Cleaning Tools” Micro Magazine June 2001. Long, CW, Peterman, J and Levit, L.B. http://www.micromagazine.com/archive/06/01/long.html

In 1990 Corona Ionization Was the State of the Art

Corona Ion Bars were available with Sub Class 1 Cleanliness

This was absolutely acceptable for semiconductor manufacturing

Fed Std 209E Class 1 requires less than one 500 nm particle/cubic foot of fab air.

The CD Compared to 500 nm Particles

500 nm

1995

2000

200520

2010

CD circa 1990

• Ionizer Performance can no longer be judged by Fed Std 209E.

• Ionizer performance must be related to KILLER Particles!

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2009 ITRS Roadmap

DRAM stagger-contacted Metal 1 (M1) ½Pitch (nm)Flash Uncontacted Poly Si ½ Pitch (nm)

Year

Criti

cal D

imen

sion

(nm

)

Semiconductor Front End Processing

2009 ITRS Roadmap

Semiconductor Fab: What Particle Size Causes Yield Loss?

For the present 45 nm node (DRAM 1st Level Metal ½ Pitch)*

Metal 1

* 2009 Intl. Technology Roadmap for Semiconductors Update, http://www.itrs.net/

90 nm45 nm

45 nm

Either of these contaminating particles can kill the die!

Define killer particle size as a ≥ ½ * 45 nm

for this 45 nm technology (allow for uneven pitch)

How Small is 22 nm?

dol-lar bill

hair germ

virus

killer

DNA

Size (um)

110 60 3 0.1 0.022

0.00200000000000001

0.003162277660168380.0316227766016838

0.3162277660168383.1622776601683831.6227766016838316.227766016838

Size of Small Ob-jects

Siz

e (

um

)

110 mm 60 mm 3 mm 100 nm 22 nm 2 nm

The invisible contaminant

Corona Ionizers and their Contamination Mechanisms

Corona Ionizers Use Sharp Points to Generate an Intense Electric Field

In time the plasma at the tips erodes the points.

Where did the material go?

This erosion is the main source of large particles and you pay extra to get points that do not erode easily.

But they still erode.

Even silicon points must be replaced every two years due to erosion.

Photograhs from http://www.ion.com/documents/technical/EmitterMaintenance.pdf

Beyond Erosion, All Corona Ionizers Turn AMC gasses into Solid Particles

This is Called Agglomeration

Range of Agglomerated Particle Emissions from High Technology Air Ionizers

0.01 0.1 10.1

1

10

100

1000

10000

Particle Size (Microns)

Part

icle

s P

er

Cu

bic

Foot

Data based upon a survey or readily available published results. E.G. see www.simco.com, www.ion.com, www.desco.com, www.meech.com

Specifying a Corona Ionizer at 0.5 mm Made Sense in 1990 but NOT in 2011!

0 0.1 0.2 0.3 0.4 0.5 0.60.1

1

10

100

Corona Ionizer 1

Particle Size (Microns)

Part

icle

s P

er

Cu

bic

Foot

Extrapolation based upon normalized 1/x3 distribution accepted by the industry

What is the Impact of These Tiny Particles? For Particles from the Cleanest Corona Ionizer…

Particle Density, (r r)=12 particles/ft3 @ 22.5 nm or greaterLaminar flow rate in Mini-environment, v= 60 ft/minWafer Residence Time in EFEM, t= 1 minute

The Number of Particles moving over a wafer :Take d=300 mm, N=(12part/ft3) (p d/2)2vt=267 particles 22.5 nm or greater!

Particles from Ionizers are Charged so Most (~50%) Will Stick!

For a 45 nm process with 22.5 nm as a killer particle size,

Particle Load/wafer~2700/2=267 particles @22.5 nm orgreater.

Assume 2% actually kill a die.Assume 500 die per wafer, 400 process steps.

Particle Limited Yield=98.67%Particle Limited Yield (1000 die/wafer)=99.27%

What Happens at the 25 nm Node?

For a 25 nm process with 10 nm as a killer particle size,

Particle Load/wafer~2700/2=1350 particles.

Assume 2% actually kill a die.Assume 500 die per wafer, 400 process steps.

Particle Limited Yield=94%!Particle Limited Yield (1000 die/wafer)=96%!

This yield loss cannot be tolerated!

1994

1996

1998

2000

2002

2004

2006

2008

2010

2012

2014

-3

-2

-1

0

1

2

3

4

5

6

7

Effect of Particle Load on Yield

yield enhancement from electrostatic micro contam-ination controlyield degradation from corona ionizer particlesNet Yield Improvement

Year

% Y

ield

Loss

Are You an Adrenaline Junkie?

Which do You Want?

Fab Contamination Particle Load Ionizer Contamination Load? Neither?

We have found a way to allow neither!It’s Called AlphaBoost®

To Understand the Advantages of AlphaBoost®, Examine how these Particles are Made:

 Cyclohexasiloxane

These chemicals are “cooked” by corona ionizers.

There are lots of organic vapors in a semiconductor cleanroom.

ANY Corona Ionizer in Fab Air will be Effected by these AMCs.

W=iV =5 mA*10kV =50 mW of heat750oC500oC100oC

25oC

The corona process generates heat at the very tip of the emitter

The heat disassembles the AMCs into radicals and cooks the “soup”.

A Free Radical Soup in an Electric Field will Grow Particles!

High Voltage On Point Creates Strong Electric Fields

Particle is drawn in by dielectrophoretic force

Particle picks up charge from emitter point

Particle is repelled from emitter point

+ -

+ -

+ -

As the Tiny Particle Crosses the Plasma (Twice) it Picks up Free Radicals from the Soup

Agglomeration: Molecules to Nano-Clusters to Micro-Clusters

Agglomeration in the Macro World:

Watch water droplets slide down the outside side of a cold glass of beer

Hail Falling From the clouds

Maintenance of Corona Ionizers Dealing with the Fuzz

Emitter points must be cleaned every few months and the ionizer must be rebalanced with a CPM

Summary:

Corona Ionizers ALL Make Sub Micron Particles

Most also make larger ParticlesCorona Ionizers all Must be Cleaned

and Re-Balanced every 1-3 months – this is expensive and time consuming.AlphaBoost® Eliminates all of these Issues

The invisible contaminant

AlphaBoost – the Advantages of Corona Without the Tradeoffs

Alpha Emitter Technology – the Engine in AlphaBoost ®

Alpha Technology Uses No High Voltage (kV) No Emitter Points No Electrical Power

Alpha Technology Requires No Cleaning No Adjusting

Alpha particles move up to 4 cm from the source and stop

They become Helium atoms and drift away harmlessly

As they Travel, each one makes ~250,000 ion Pairs`

No electricity is required to make ions

Ion output is automatically balanced with no adjustments.

Alpha Emitter Technology Employs Po210, a 5.3 MeV Alpha Source

The Alphas Collide with Air Atoms and Ionize Them

ionion

ion

ion

ion

ion ion

ion

ion ion

The process continues as long as the source is active ((1-2 years)

Is the Alpha Source Safe?

Yes! Safety Rules:

Alpha particles are stopped by a sheet of paper or by the dead skin

covering your body

Once they stop, Alpha particles become harmless helium atoms

Don’t eat alpha sources

Don’t smoke alpha sources!

Return them after they are spent They convert into lead

Ordinary Alpha Ionizers In Laminar Airflow may not Discharge an Entire EFEM

ULPA

No Ions Here!

Ions Recombine Before they Reach the Target

Alphaboost™ Separates Ion Polarities and Push Ions down Electrostatically in Waves

±300 - 500 V

Height of EFEM

Laminar Flow VelocityHalf Cycle ~

Ions move 1+ m!

The Product is Compact and Easy to Mount in an EFEM

The ionizing element is the size of a coin

AlphaBoost Has

No KiloVolt voltages No Need for Balance Adjustment No Corona No Sharp Points to Wear Out No Fuzz Ball Creation Mechanism No Gas to Particle Agglomeration

Mechanism

Ionizer LPC Cleanliness Study *

94.2±4 particles/ft3 with ionizer ON and 95.5±3 particles/ft3 with ionizer OFF

*Robert Wilson, ESDA Symposium 1987, A Novel Nuclear Ionization Source Employing a Pulsed Electric Field

Ionizer CNC Cleanliness Study *

*Robert Wilson, ESDA Symposium 1987, A Novel Nuclear Ionization Source Employing a Pulsed Electric Field

1.25.2±0.9 particles/ft3 with ionizer ON and 3.3±0.15 particles/ft3 with ionizer OFF

AlphaBoost® Discharge Performance

Operation of AlphaBoost® in an EFEM

ULPA

80 fpm air flow Typical Discharge Performance 1 m below the ionizer :

Discharge times ± 25 seconds

Voltage Swing +15 V

Set to ±500 V Bias Swing

Frequency 2.0 Hz

Operation of AlphaBoost® Adjacent to a Wafer Aligner

ULPA80 fpm air flow

75 cm

25 cm

Typical Discharge Performance 25 cm below the ionizer :

Discharge times ± 7 seconds

Voltage Swing +5 V

Set to ±300V Bias Swing

Frequency 4.0 Hz

AlphaBoost® Benefits

Fast Discharge time Balanced by Physics, not by

Adjustment Inherently Stable No Fuzzball to Clean Off No points to Replace No CPM Balance Adjustment Same Delivery Efficiency as Corona

Technology

AlphaBoost – Conclusions

Conclusions

Records went from the phonograph cylinder to 78 RPM hard plastic to Vinyl High Fidelity Recordings and Underwent Constant Improvement of the Same Technology But they Eventually they Became Obsolete – limited life, sensitivity to

handling & to dust

Cameras went from the pin-hole to lens to multi element lenses but it took digital photography to satisfy today’s photographers.

Corona Ionizers underwent Technology boosts from Tungsten to Titanium to Silicon points and from AC to DC to Pulsed DC to Complex Waveforms But Technology has passed them by

Electricity was Generated by Burning Dirty Coal in 1900. Now Clean Solar Electrical Power is Coming on Line rapidly!

Semiconductors at the 25 nm Node and Beyond Require Alphaboost® to Fab Chips Cleanly and Economically

2008 2010 2012 2014 2016 2018 2020 2022 2024 20260

10

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40

50

60

Year

Criti

cal D

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(nan

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