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Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
Understanding Brewer Science’s
Bottom Anti-Reflective Coatings
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
Overview
• Anti-reflective coating introduction
• Types of anti-reflective coating
• Advantages to anti-reflective coatings
• Advantages to bottom anti-reflective coatings
• Guide to products and compatibility
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
Substrate
ARC
ExposureEnergy
Anti-Reflective Coating Introduction
• Anti-reflective coatings (ARC) can do several things– Absorb light entering the material by light absorbing compounds in material.
– If ARC is the correct thickness can cause destructive interference of reflected light.
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
Types of Anti-reflective Coatings
• Organic– Applied like a photoresist
– Top anti-reflective coating (TARC)
– Applied after the photoresist
– Absorbs light to give little reflection at substrate/resist surface
– Bottom anti-reflective coating (BARC)
– Applied before the photoresist
– Absorbs light and uses destructive interference to give little reflection at theresist/ARC interface
• Inorganic– Deposited on substrate in special deposition chamber
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
Property Organic ARC Inorganic ARCReflectivity and swing ratioreduction - 1st minimum
++ +++
Reflectivity and swing ratioreduction - 2nd and higher minima
+++ 0
Etch rate 0 or + +++Coating conformity 0 ++Thickness tolerance + 0Plasma damage +++ --Refr. index reproducibility +++ 0Throughput ++ +Cost of Ownership + 0Stack issues +++ -Planarization capability ++ --Rework capability +++ --
Organic and Inorganic ARC
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
Advantages of Anti-Reflective Coatings
• Eliminates swing effect and standing waves in
photoresist
• Solves topography related lithography problems
• Provides ultimate critical dimension (CD)
control
• Expands process capabilities.
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
Exposure Energy Exposure Energy
Standing Wave
Reflective Notching
Resist
ResistARC®
Topography Related Lithography Problems
• Light reflecting off underlying substrate reduced or eliminated– Backscattering
– Reflective notching
– Standing Waves
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
Light Light
Unexposedphotoresist
MetalLine
Reflective Notching
Metalline
Photoresist
CrossSection
Reflective Notching
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
0.4µm on 2500Å steps using 1844Å XHRi
Competitor BARC
Reflective Notching
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
Dose to Clear Swing
Resist Thickn ess (nm)
Dos
e (m
J)
5 0
5 5
6 0
6 5
7 0
7 5
8 0
8 5
9 0
9 5
100
850 900 950 1000 1050
No ARC
XHRi
Swing Effects• Dose to clear swing curve defined as the amount of light required
to completely expose photoresist
• Swing curves reduced with application of BARC
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
0 .00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0
ARC®Thickness
AluminumGaAsPolyTungsten
BARC Reflectivity Curve
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
0.4µm with 2500Å Steps with 1844Å ARC XHRi
High Area
Transition Flat Area
Low Area
Resist Profiles on Topography
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
Advantages of organic BARC
• Can apply with existing photoresist application systems
• Do not need expensive deposition chambers
• Prevents chemical interaction between photoresist and substrate– BARC acts as wall to nitrogen poisoning with chemically amplified photoresists
• Increases CD control– Eliminates reflective notching
– Eliminates standing waves and scattered light
• Extends lithography process window– Increases stepper focus latitude
– Maximizes photoresist exposure latitude
– Increases usage life of stepper.
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
0
200
400
600
800
1000
1200
1400
1600
1800
2000
1000 1500 2000 2500 3000 3500 4000 4500 5000
Spin Speed (RPM)
DUV42-6DUV42-8DUV42-11
Example Spin Speed Curve
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
PEK-103 0.20µm L/S Resist on DUV42
Lines With or Without BARC
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
Guide to BSI BARC’s
• Exposure wavelength– G-line, I-line, DUV, 193nm
• Planar or conformal BARC– Worst case step height
– CD tolerances needed
• Wet or dry processing– Depending on equipment availability, CD and wavelength
– Wet process BARC develops away with resist
– Dry process BARC requires a gas etcher
• Choose BARC based on resist chosen– DUV resists have two chemistries
– ACETAL
– ESCAP/TBOC
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
PLANAR BARC
RESIST RESIST RESIST RESIST
CONFORMAL
BARC
EQUALRESIST
THICKNESS THINRESIST
EQUIVALENTBARC
THICKNESS
SUBSTRATE SUBSTRATE
Planar vs Conformal BARC
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
InorganicDeveloper Insoluble
OrganicDeveloper Insoluble
OrganicDeveloper Soluble
Exposure
Development
Etch
Stripping
SubstrateAnti-reflectiveBottom coat Photoresist
Wet or Dry Etch Processing
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
Bake Latitude
CD
Bake Temperature
Stable Lines Spaces Clear
MissingPattern
SpaceResidue
Stepper & Resist Resolution Limit
What is a Bake Window?
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
0.35 µm Dense Lines
177°C Bake 205°C Bake
Wet or Dry Etch Patterning
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
Planar BARC gives superior photo performanceConformal BARC gives superior etch performance
Various viscosities available in each family
BSI BARC Product Families
• G-line (broadband material)– Wet or dry process
– XLT– XLX
• I-line– Wet or dry process
– WiDE– Dry process only
– XHRi– XHRiA
• DUV– Dry Process Only
– ESCAP/TBOC compatable– DUV30 (planar)– DUV42 (conformal)
– ACETAL compatable– DUV32 (planar)– DUV44 (conformal)
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
Etch Capabilities
• Successfully dry etched in various chemistries
– HBr
– O2
– Cl2, HCl
– CF4, C2F2
– N2
– Carrier gases: He, Ar
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
After HBr/O2 etch.∆CD = 0.026µm.Selectivity = 0.85
After He/O2 etch.∆CD = 0.024µm.Selectivity = 1.04
After Cl2/O2 etch.∆CD = 0.013µm.Selectivity = 1.48
DUV42 Etch Performance
Brewer Science Inc., Rolla MO, USAEffective Date: 0X/0X/02 DCIF: MKT00XX Doc. Control#: F.6.6.010X.A
Cleaning/Stripping Capability
• BARC can be removed by common photoresiststripping processes
– Oxidizing plasma or oxidizing solvent strip processes
– Ozone Plasma Strip
– O2 Plasma
– Piranha
– RCA Clean