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Transforming Technologies Presents. Outline  Microcontamination, Electrostatics and High Tech Manufacturing  Corona Ionizers and their Contamination.

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Presentation on theme: "Transforming Technologies Presents. Outline  Microcontamination, Electrostatics and High Tech Manufacturing  Corona Ionizers and their Contamination."— Presentation transcript:

1 Transforming Technologies Presents

2 Outline  Microcontamination, Electrostatics and High Tech Manufacturing  Corona Ionizers and their Contamination Mechanisms collide with the 25 nm node  Alphaboost® The Advantages of Corona without the Tradeoffs  Summary

3 Micro-Contamination in High Technology Manufacturing

4 Particle attraction & bonding to charged surfaces Damage to product Robotic lockup Effects of Static Charge on High Technology Manufacturing

5 5 Contamination Study Wafer at 0 V class 1 mini environment for 6 weeks Wafer at 2000 V class 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 A Particle Contamination Study

6 Electrostatic Attraction Defeated by Mini-Environment Ionizers “Implementing a Static Control Program to Increase the Efficiency of Wet Cleaning Tools” Micro Magazine June Long, CW, Peterman, J and Levit, L.B.

7 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.

8 The CD Compared to 500 nm Particles 500 nm CD circa 1990 Ionizer Performance can no longer be judged by Fed Std 209E. Ionizer performance must be related to KILLER Particles!

9 Semiconductor Front End Processing 2009 ITRS Roadmap

10 Semiconductor Fab: What Particle Size Causes Yield Loss? For the present 45 nm node (DRAM 1 st Level Metal ½ Pitch)* Metal 1 * 2009 Intl. Technology Roadmap for Semiconductors Update, 90 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)

11 How Small is 22 nm?  m  m  m  nm  nm  nm

12 The invisible contaminant Corona Ionizers and their Contamination Mechanisms

13 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

14 Beyond Erosion, All Corona Ionizers Turn AMC gasses into Solid Particles This is Called Agglomeration

15 Range of Agglomerated Particle Emissions from High Technology Air Ionizers Particle Size (Microns) Particles Per Cubic Foot Data based upon a survey or readily available published results. E.G. see

16 Specifying a Corona Ionizer at 0.5  m Made Sense in 1990 but NOT in 2011! Particle Size (Microns) Particles Per Cubic Foot Extrapolation based upon normalized 1/x 3 distribution accepted by the industry

17 What is the Impact of These Tiny Particles? For Particles from the Cleanest Corona Ionizer…  Particle Density,  r  12 particles/ft 22.5 nm or greater  Laminar flow rate in Mini-environment, v= 60 ft/min  Wafer Residence Time in EFEM, t= 1 minute  The Number of Particles moving over a wafer :  Take d=300 mm, N=(  part/ft 3 )  d/2) 2 vt=  267 particles 22.5 nm or greater!

18 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 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%

19 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!

20

21 Are You an Adrenaline Junkie?

22 Which do You Want?  Fab Contamination Particle Load  Ionizer Contamination Load?  Neither? We have found a way to allow neither! It’s Called AlphaBoost®

23 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.

24 ANY Corona Ionizer in Fab Air will be Effected by these AMCs. W=iV =5  A*10kV =50 mW of heat 750 o C 500 o C 100 o C 25 o C The corona process generates heat at the very tip of the emitter The heat disassembles the AMCs into radicals and cooks the “soup”.

25 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 + -

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

27 Agglomeration: Molecules to Nano-Clusters to Micro-Clusters

28 Agglomeration in the Macro World: Watch water droplets slide down the outside side of a cold glass of beer Hail Falling From the clouds

29 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

30 Summary:  Corona Ionizers ALL Make Sub Micron Particles  Most also make larger Particles  Corona Ionizers all Must be Cleaned and Re- Balanced every 1-3 months – this is expensive and time consuming.  AlphaBoost® Eliminates all of these Issues

31 The invisible contaminant AlphaBoost – the Advantages of Corona Without the Tradeoffs

32 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

33  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 Po 210, a 5.3 MeV Alpha Source

34 The Alphas Collide with Air Atoms and Ionize Them ion The process continues as long as the source is active ((1-2 years)

35 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

36 Ordinary Alpha Ionizers In Laminar Airflow may not Discharge an Entire EFEM ULPA No Ions Here! Ions Recombine Before they Reach the Target

37 Alphaboost™ Separates Ion Polarities and Push Ions down Electrostatically in Waves ± V Height of EFEM Laminar Flow Velocity Half Cycle ~ Ions move 1+ m!

38 The Product is Compact and Easy to Mount in an EFEM The ionizing element is the size of a coin

39 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

40 Ionizer LPC Cleanliness Study * 94.2±4 particles/ft 3 with ionizer ON and 95.5±3 particles/ft 3 with ionizer OFF *Robert Wilson, ESDA Symposium 1987, A Novel Nuclear Ionization Source Employing a Pulsed Electric Field

41 Ionizer CNC Cleanliness Study * *Robert Wilson, ESDA Symposium 1987, A Novel Nuclear Ionization Source Employing a Pulsed Electric Field ±0.9 particles/ft 3 with ionizer ON and 3.3±0.15 particles/ft 3 with ionizer OFF

42 AlphaBoost ® Discharge Performance

43 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

44 Operation of AlphaBoost® Adjacent to a Wafer Aligner ULPA 80 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

45 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

46 AlphaBoost – Conclusions

47 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 Now Clean Solar Electrical Power is Coming on Line rapidly!

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


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