Science Behind the Seals - IEUVIieuvi.org/TWG/Mask/2011/MTG101611/18-EUVL-Mask-TWG... · Ge Mao...
Transcript of Science Behind the Seals - IEUVIieuvi.org/TWG/Mask/2011/MTG101611/18-EUVL-Mask-TWG... · Ge Mao...
Science Behind the Seals
Defect Reduction beyond 32nm
EUV Mask TWG 10/16/2011
Jeff Blouse, Applied Seals NA
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AGENDA
Who is Applied Seals
Evolution of Elastomers in the Semiconductor
Industry
Case studies of current particle issues
Challenges beyond 32nm
Headquarters & Engineering Design Center:
Newark, California USA
Manufacturing Location:
Chang Hua County, Taiwan
Parent Company:
Ge Mao Rubber Industrial Co., Ltd. (GMORS)
S M A R T SEALING™
• Founded in 1981 (Second Largest Seal Producer in Asia)
• FY2011 Revenue est. > 90 million USD
ASNA Vital Stats:
● 55,000 ft2 mfg. facility
● Production & packaging entirely down to Class 100 clean rooms
● ISO3601-1 and ISO 3601-3 o-ring standards, ISO9001/9002 and
AS9100 quality certifications, ISO13485 quality certified
● 100% control of production process, from tooling through final packaging
● One of only a few elite suppliers with FEA capabilities
Metallic and Carbon fillers
are used to enhance
physical properties to handle
higher pressures(>500Psi) -
that is the primary purpose
O-rings were invented in
1896 and are one of the
simplest, yet most
engineered, precise and
useful seal designs ever
produced
O-rings were
originally developed
for Industrial &
Aerospace markets
O-rings & seals were never
developed to meet
semiconductor needs
FACT
Evolutionary advances in sealing
technology have attempted to
keep pace with Semi
requirements
Semiconductor Seal Applications
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What major corporation was
divested due to the misapplication of
an oring?
Morton Thiokol in 1989
Challenger disaster
Jan 28, 1986 –
Incorrect Coefficient of Thermal
Expansion for the operational
temp range.
Process Temperature Range Requirements Applications
Lithography 25-100°C NMP
Solvents
IPA/Acetone
HfO2
Door/lid seals
Drain seals
Chemical container
seals
Fittings
Dispensing valves Etching
Stripping
80-200°C Piranha
Amines
RCA (Acid/Base)
H2O2/NH3/HNO3
Cleaning 25-200°C UPDI
Ozone
Low extractables
Oxidization
Diffusion
150-300°C N2
O2
H2O
HCl
Quartz chamber seal
Fittings
Center ring
KF flanges
LPCVD 150-300°C NH3
SiH2Cl2
HCl
Lamp Anneal 150-300°C Resistance to
IR absorption/
low outgassing
WET
THERMAL
Semiconductor Seal Applications
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Process Temperature Range Requirements Applications
Etching 25-220°C CF4/CHF3
SF6, NF3
BCl3/CCl4/O2
Dynamic:
Gate valve
Door seal
Lip seal
Static:
Chamber lid
Electrode seal
Lamp seal
Exhaust valve
Gas inlet/outlet
Window seal
Center ring
Fittings
Carrier:
Wafer
LCD panel
Conveyor
Ashing 25-250°C O2/O3/H2O
PECVD/
APCVD
25-200°C TEOS/O3
SiH4/O2
HCl/CF3/HBr
NF3/CF4/C2F6
PVD 25-250°C Ar
Metal CVD 25-250°C TEOS/O3
SiH4/O2
HCl/CF3/HBr
NF3/CF4/C2F6
WF6
Transfer Valves
Control Valves
25-150°C Various chemicals Pump
Valve
Vacuum equipment
Ancillary
Vacuum
Equipment
PLASMA DEPOSITION
PLASMA ETCH
Source: Applied Seals North America
Semiconductor Seal Applications
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• NBR
• HNBR
• EPDM
• Silicone – VMQ
• Fluorosilicone – FVMQ
• Chloroprene/Neoprene – CR
• Polyurethane – AU or EU
• Polyacrylate – ACM
• Vamac® – AEM
• Aflas® – Tetrafluoroethylene
• Propylene – TFE/P
• Natural Rubber – NR
• Butyl Rubber – IIR
• Chlorobutyl Rubber – CIIR
• Epichlorohydrin – ECO
• Styrene Butadiene – SBR
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• FKM (a.k.a. Viton®)
• Specialty Hybrid
• PERFLUOROELASTOMER-FFKM
(Perfrez®, Chemraz® & Kalrez®)
Understanding Elastomers Elastomer Families
Evolution of a Perfluoroelastomer How and Why Various Seal Compounds Lineup
N Butile Rubber
(NBR) FKM-
(Viton®) Hybrid FFKM-Perfluoro
% C-F Bonding 0 % 100 %
Compatibility in Harsh Semi Processes Poor Best
COST High Low
Fluorosilicone
(FVMQ)
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What’s in an O-Ring?
• Base Polymer – repeating chain of carbon
monomers
• Fillers – additive to enhance sealing
strength
• Curatives – cross linking agents that
catalyze the vulcanization process
Ausimont
(Solvay) 3M DuPont Daikin NOK
Sealing Considerations Optimal Seal Material
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Ratio of Fillers to Base Polymer
FFKM Compound
Filler
~15%
other
Sealing Considerations Optimal Seal Material (Compound Mixes)
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Reduce Metal Ions
Enhance Purity of Material
Barium Sulphate
Silica
Sealing Considerations Optimal Seal Material and Preparation
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Parameter RL Units Silica FFKM #1 Nano-Silica FFKM #2 Nano-Silica FFKM#2,Revised
Aluminum (Al) 5 ppb (ng/g) 1300 850 350
Barium (Ba) 5 ppb (ng/g) 9000 1200 5
Beryllium (Be) 50 ppb (ng/g) * * *
Bismuth (Bi) 50 ppb (ng/g) * * *
Cadmium (Cd) 5 ppb (ng/g) * * *
Calcium (Ca) 50 ppb (ng/g) 1200 2000 500
Cesium (Cs) 5 ppb (ng/g) * * *
Cobalt (Co) 5 ppb (ng/g) 29 * 1
Gallium (Ga) 5 ppb (ng/g) * * *
Indium (In) 5 ppb (ng/g) * * *
Lead (Pb) 5 ppb (ng/g) 7 8 6
Lithium (Li) 5 ppb (ng/g) * * 3
Magnesium (Mg) 5 ppb (ng/g) 32 200 120
Manganese (Mn) 5 ppb (ng/g) 35 11 10
Molybdenum (Mo) 30 ppb (ng/g) * * *
Nickel (Ni) 5 ppb (ng/g) 250 28 53
Potassium (K) 50 ppb (ng/g) 170 170 60
Rubidium (Rb) 5 ppb (ng/g) * * *
Silver (Ag) 50 ppb (ng/g) * * *
Sodium (Na) 30 ppb (ng/g) 470 5200 1800
Strontium (Sr) 5 ppb (ng/g) * 22 *
Thorium (Th) 50 ppb (ng/g) * * *
Tin (Sn) 50 ppb (ng/g) * * 120
Vanadium (V) 5 ppb (ng/g) * * *
Zinc (Zn) 50 ppb (ng/g) 300 290 500
Zirconium (Zr) 50 ppb (ng/g) * * 20
Sealing Considerations Optimal Seal Material
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Source: Independent lab, 2010
NF3Plasma Test Results - Weight Loss
BaSO4 (Barium Sulphate)
• Provides great ETCH rate
• Not suitable for ULTRA clean
applications
Carbon Black
• Improves strength and toughness
• Lower Etch Rate but Powdering
• Outgassing and Particle concern
Nano-PTFE
• Low Defect Material
• Reduced Sealing Strength
• Seal Design enhancements often
needed
SiO2 (Silica)
• Increased Etch Rate
• Decreased Particulation
TiO2 (Titanium Dioxide)
• Helps shield the base polymer from
plasma
• Whitens the material
Sealing Considerations Optimal Seal Material
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Test # Brand name Filler
30 min 60 min
Weight loss (%) Weight loss (%)
1 Perfrez® 6012 BaSO4 1.14% 1.90%
2 Perfrez® 6011 Carbon Black 1.54% 1.99%
3 Perfrez® 6021 Carbon Black 0.95% 1.19%
4 Perfrez® 6040 Nano-PTFE 3.19% 6.94%
5 *Perfrez® 5033
(Hybrid) Nano-PTFE 2.67% 5.11%
6 Perfrez® 6015 SiO2 + TiO2 4.73% 9.67%
7 Perfrez® 6022 SiO2 + TiO2 5.03% 9.03%
5 Kalrez® 8085 SiO2 + TiO2 4.91% 10.21%
8 Kalrez® 9100 SiO2 + TiO2 4.91% 10.21%
10 Chemraz® E38 SiO2 5.55% 10.99%
*Perfrez 5033 – Hybrid (FKM/PTFE)
What else differentiates a FFKM?
FFKM Compound
Filler
~15%
other
Sealing Considerations Optimal Seal Material (Compound Mixes)
Peroxide
Triazine
Bisphenol
Cure System
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Bisphenol cure system
Triazine cure system
Poor chemical resistance to steam and amines
Good with acids and solvents and higher temperature
Marginal with amines and alkali. Poor in acids and also higher temperature
320°C 260°C 280°C
Triazine Peroxide Bisphenol
Heat Resistance
35%
15%
50%
Triazine Peroxide Bisphenol
Compression Set
Perfluoroelastomers (FFKMs): Cure Systems
Peroxide cure system (iodine)
Best overall chemical resistance
Less “Sticky”
Shown to have a better compression set
Sealing Considerations Optimal Seal Material (Cure System)
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Defect Reduction
The Dirty Truth –
Seals are a contamination source
Materials – Polymers,
Fillers, Curatives
Molding – process and
quality control
Manufacturing Facilities –
Class 100 Clean Rooms
Compound B
RMS 6
Compound A
RMS 32
Compound A demonstrates a much rougher surface
Sealing Considerations Life Time Improvement – Reduced Particulate Generation
Effect Surface Finish
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Source: 2010, Solvay
Compound A
After Plasma
• Tooling
• Deflashing
Methods
What Effects
Surface Finish?
0
2
4
6
8
Weight Loss %
Compound
A
Perc
enta
ge (
%)
O2
NF3
O2
NF3
1.56%
6.28%
0.61%
1.90%
PERFREZ® 6012
Original
Sealing Considerations Life Time Improvement – Reduced Particulate Generation
PERFEZ®
6012
Compound 2
After 20,000 Wafers Degradation on seal. No powder observed on seal
because nanofillers are pumped away
Perfrez 6022
After 30,000 Wafers No signs of seal deterioration, no powdering
Sealing Considerations: Remote Plasma Source Reduced Defect Generation - Life Time Improvement
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Custom shape, correct
compound and proper
installation procedures
allow for particles and leak
rate baseline to be
reached
Compound 3 installed 05/02/08.
Particle & leak checked over 30k wafer count
Changing Compound to a
Silica and TiO2 filled
material
increased wafer
output to 30,000
20,000
30,000
0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
Compound 2 Compound 3
Perfrez 6022 Improvement Increased Wafer Output
Wa
fer
Ou
tpu
t (p
er
PM
)
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Sealing Considerations: Remote Plasma Source Reduced Defect Generation - Life Time Improvement
(Asher)
Microwave – RF system
Chemistries: CF4, N2, O2, H2/N2 3%, water vapor
o Compression of Seal,
due to elevated
temperatures
o Seal severely etched
o White Powder
Residue
o Seal severely etched
o Damaged during Installation
o Dark Residue on Seal
o Seal twisted in Gland
Seal Issues:
• Seal Life unable to meet 10K wafers (per clean)
• Seal Performance Inconsistency
• Failure Mode – Particle Adders past Baseline
• “Problem” Seals in KIT are Chamber Lid and Door Chamber
• Both Seals severely etched (Vacuum Integrity)
Optimizing Seal Design & Material Selection BKM
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• SPC chart of weekly tool qualification
• Excursion on 5/12: chamber was brought back into control with
process response (no physical maintenance intervention)
Blue –Process of Record
Pink – New Seal Design and Perfrez 6015
Acceptable Particle
Limit
New Seal Design
with Perfrez 6015
Process of Record
Optimizing Seal Design & Material Selection BKM – Results (Iridia)
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25 Source: ISS 2011, IC Insight
•Higher purity Components
•Higher purity Elastomers
Below 32nm Ground Rules – the Industry can no
longer ignore Seals as a Contamination Source
S M A R T SEALING™
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Defect Reduction
Where do we go from here?
Materials
Advanced Polymers
Nano- PTFE & PFA Fillers
Ultra Clean Silica Fillers
Filler Deionization
Industry Partnerships
Cryogenic Deflash
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Source: SMC 2011, JSR 100um 50um 200nm 20nm <10nm
Required Elastomer Filler
Sizes
S M A R T SEALING™
Road to Single-Digit Nano-Lithography
Low Defect Materials Nano-Filled Technology
S M A R T SEALING™
High Purity Seals - PTFE / PFA nano-composites
ASNA CONFIDENTIAL
S M A R T SEALING™
SEMATECH’s resist and materials
development center
30 Source: SEMATECH Symposium Taiwan 2011
Provides world-class EUV imaging capabilities
Defect-free EUV masks
--- 24/7 operation (9k wafers/year)
--- EUV research effort concentrating on novel approaches such as new
polymers and underlayers
Worldwide associate member program
--- Added Nissan, Sumitomo, Fujifilm in 2011; total of 10 associate members
And Oct 11, 2011 added
Applied Seals North America
Slit Valve Because of valve’s proximity
to wafers, limiting particle
generation in this region is a
critical component of slit valve
reliability.
Sealing Considerations Bonded Elastomer Technology
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• Lowest defect material for 45nm production
New Clean Silica filled elastomer used in 13.5nm MOCVD
System
S M A R T SEALING™
• New Metrology for sub-32nm processes revealed
unacceptable levels of elastomer contaminants
DRT1101048.14.spe
500 1000 1500 2000
Kinetic Energy (eV)
3
4
5
6
c/s
x 1
05
DRT1101048.16.spe
300 400 500 600 700
Kinetic Energy (eV)
-4
-2
0
2
c/s
x 1
05
Background Defect
Particle sizes 50 to 120 nm
Source: Sematech 2011
Defect Reduction
Ultra Clean Silica Fillers
Cleanest materials are irregular
shapes with a spiked
morphology Trace metals found in finished
product
Abrasion in the molding
process?
Micro abrasion within the seal
Defect Reduction
Deionization of Fillers
Nano filled compounds use
20 – 40 nm particle sizes
During compound mixing and
vulcanization, silica particles
agglomerate into 100nm
defects and larger
Source: Sematech 2011
O-ring parting line
Sealing surface
Sealing surface
The Deflash Process
Cosmetic Surgery?
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Conventional vs Cryogenic Deflash
6022 Sample #1 and #2 Comparison
Conventional Deflash Cryogenic Deflash
Conventional vs Cryogenic Deflash
After Plasma Treatment
6022 Sample #1 and #2 Comparison
Conventional Deflash Cryogenic Deflash
Conventional vs Cryogenic Deflash
After More Aggressive Plasma Treatment
6022 Sample #1 and #2 Comparison
Conventional Deflash Cryogenic Deflash
2010 2014 2011 2012 2015 2013 2016 2009
100% Cleanroom Manufacture and packaging
Base polymer Supply Chain Collaboration
Ultra Clean Filler Development
Filler size management
Filler Ionization Control
Advanced de-Flash Procedures
Surface Finish Engineering
Elastomeric Sealing Standards
Curative Development
FFKM Evolution – atomic level polymers
32 20 28 25 18 23 15 38
Flash ½ Pitch, nm
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Applied Seals Technology Development Roadmap
Summary
Seals are a contamination source
Compound
Seal Design
Hardware
Process
Optimal sealing performance
Be educated – It’s not
just an o-ring
Fillers Stretch
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Advances in Semiconductor
Process Technology, Materials and
Metrology, require revolutionary
advances in sealing technology.