The Business of Science®
Oxford Instruments
Plasma Technology
Ion beam processing
– the role of vacuum quality
Vacuum Symposium, 12th October 2016,
Coventry
Dr David Pearson – Senior Ion Beam Technologist
© Oxford Instruments 2016
CONFIDENTIAL
Page 1
The Business of Science®
•
Overview of IB processing and Oxford IBD/IBE tool
•
Types of pumps - pumping speed and process gas flows
•
Vacuum integrity, base pressure and residual gases
•
IB processes and effects of background gases
•
Examples of customer applications
•
Discussion and questions
© Oxford Instruments 2016
CONFIDENTIAL
Page 2
Broad ion beam thin-film processing
The Business of Science®
Oxford DIBS system is coplanar
• also available as deposition only or etch only
Substrate
RF inductivelycoupled plasma
ion sources
Etch
Etching/preclean/assist/
surface mod
Deposition
Target
© Oxford Instruments 2016
CONFIDENTIAL
Page 3
Some advantages of broad ion beam processing
The Business of Science®
General
• Independent control of beam energy and ion flux (50eV – 1500eV)
• Lower pressure processing environment (High E-5 to mid E-4 Torr range)*
Deposition
•
•
•
•
•
Good control of stoichiometry for a wide range of materials*
Precision film thickness control and repeatability*
Excellent control and reproducibility of other physical properties*
Reduced porosity/high density in deposited films (low pressure = reduced
included gas)
Very high quality optical films with super smooth surfaces (~1Ang)*
Etching
• Etches all known materials
• Angled etch beam for profile/sidewall control and feature shaping*
• Precision control of etched depth/etch stop*
* Vacuum quality and residual background species can affect this performance!
© Oxford Instruments 2016
CONFIDENTIAL
Page 4
Process Materials Library
The Business of Science®
Ion Beam Etching
Material
Gas
Material
Gas
Material
Gas
Material
Gas
Au
Ar
SiO2
Ar, SF6,CHF3
SiN
Ar
SOI
Ar, Cl2
Pt
Ar
Al2O3
Ar
TaN
Ar
CaF2
Ar
Pb
Ar
MgO
Ar
TiW
Ar, CHF3
Diamond
Ar
Ti
Ar
CeO2
Ar
TiW:N
Ar
DLC
Ar
Ta
Ar
SrTiO3
Ar
MnIr
Ar
InP
Ar, Cl2
Ni
Ar
LaAlO3
Ar
CoFe
Ar
GaAs
Ar, Cl2
Cu
Ar
LiNbO3
Ar, CF4, CHF3
FeMn
Ar
InGaAsP
Ar, Cl2
Al
Ar
KTaO3
Ar
NiFe
Ar
ZnS
Ar
Ru
Ar
SrTiO3
Ar
NiCr
Ar
HgCdTe
Ar
Ag
Ar
NbSrTiO3
Ar
FeNiCo
Ar
Rh
Ar
YBaCu3O7
Ar
CoFeB
Ar
NiMnGa
Ar
© Oxford Instruments 2016
CONFIDENTIAL
Page 5
OIPT Ionfab300+ DIBS chamber configurations
The Business of Science®
Two different size chamber designs depending on process requirements
Standard Chamber (SC) version
© Oxford Instruments 2016
Ionfab300+ Large Chamber (LC) version
CONFIDENTIAL
Page 6
Product range and configuration
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Ionfab300Plus (S/C) – Standard chamber
• Specifications: etch and/or dep tool
•
•
•
•
15cm etch source for up to 4” sample size
15cm deposition source for up to 8” sample size
Up to 4 x 225mm square target assembly
MESC compatible
© Oxford Instruments 2016
CONFIDENTIAL
Page 7
Product range and configuration
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Ionfab300Plus Opto
• Specifications: High quality precision optical coating tool
•
•
•
•
•
•
15cm etch source for substrate pre-clean or deposition assist
15cm deposition source for up to 8” sample size
Up to 4 x 225mm square target assembly
High speed rotation platen (up to 500 rpm or more) for high uniformity/yield
Patented in situ White Light or laser optical monitor
MESC compatible
Patent: EP1540032B1
© Oxford Instruments 2016
CONFIDENTIAL
Page 8
Product range and configuration
The Business of Science®
Ionfab300Plus (LC) large chamber
• Specifications: Etch and/or dep tool
• 30cm etch source for up to 8” sample size
• 15cm deposition source for up to 8” sample size
• Up to four x 250mm square target assembly
© Oxford Instruments 2016
CONFIDENTIAL
Page 9
Standard chamber configuration
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• S/C substrate holder with shutter open
and closed
• Targets, neutraliser, CAIBE gas ring,
substrate loading slot and OS fibre head
can be seen
© Oxford Instruments 2016
CONFIDENTIAL
Page 10
Large chamber configuration
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Large chamber (L/C)  up to 8in etch/dep applications
• Designed for 30cm etch source  enables good uniformity etch up to 8in
• 15cm deposition source  good deposition uniformity up to 8in
• max target size 250mm sq
Standard chamber (S/C)  up to 4in etch apps, or up to 8in dep at higher rate than L/C
•15cm etch source  good uniformity up to 4in
•15cm deposition source  good deposition uniformity up to 8in {max target – 225mm sq}
• Approx twice the deposition rate of the L/C
© Oxford Instruments 2016
CONFIDENTIAL
Page 11
Ion source design
The Business of Science®
15 cm etch or deposition source
Neutraliser
“Screen”
Decelerator
Gas diffuser
Electrostatic shield
Quartz tube
Accelerator
Two graphite grids set
Helical RF antenna
© Oxford Instruments 2016
CONFIDENTIAL
Page 12
Ion source design
The Business of Science®
30 cm etch source
Neutraliser
“Screen”
Decelerator
Accelerator
Three molybdenum grids set
© Oxford Instruments 2016
CONFIDENTIAL
Page 13
Ion beam formation grids
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Plasma
Screen
Accelerator
Decelerator
Ion beam collimation optics
inside
Source
Positive ions go towards
ground
at beam
Voltage
(screen)
• Triple molybdenum or graphite collimating grid set for broad
ion beam formation
• Screen grid (+ve voltage): determines ion beam energy and
measures beam current
• Accelerator grid (-ve voltage): helps to extract ions and
provides focussing for ion beamlet
• Decelerator grid (grounded): enhances beam collimation,
reduces electron backstreaming and re-deposition in source
 Benefits of three grid configuration:
• Controls divergence of beam better compared with two grid version
• Focussed spot on target minimizes beam overspill and film contamination
• Reduces deposition on active grids and in source so reduces tool downtime
© Oxford Instruments 2016
CONFIDENTIAL
Page 14
Neutralising the ion beam
The Business of Science®
+ -+
+
+
-
+
+
+
Plasma Bridge
Neutraliser (PBN)
Neutralisers – two main purposes:
• Produces electrons for starting the ion source
• Produces electrons for neutralising the beam
• Helps reduce beam divergence
• Filamentless High Power Neutraliser produces up to 1.3A
• Lifetime and maintenance cycle improved > 500 hours
© Oxford Instruments 2016
CONFIDENTIAL
Page 15
Filamentless neutralisers
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© Oxford Instruments 2016
CONFIDENTIAL
Page 16
Chamber pumping and base pressure
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Low Vacuum
Medium Vacuum
High Vacuum
Ultra High Vacuum
Torr or
mBar
Vacuum
Pumps
Vacuum
Gauges
Rotary vane Pump
Diaphragm Pump
Screw Pump
Roots Pump
Diffusion Pump
Turbomolecular Pump
Sputter Ion Getter Pump
Cryo Pump
Pirani gauge
Penning gauge
Ion gauge
Capacitance manometer
Processing
pressure range
Ultimate base
pressure range
~10s cm  1m
MEAN FREE PATH
 Essentially collisionless regime
© Oxford Instruments 2016
CONFIDENTIAL
Page 17
Chamber pumping and base pressure
The Business of Science®
Pumping configurations
Cryo only
– 3000l/s
© Oxford Instruments 2016
Turbo only
– 1600l/s
CONFIDENTIAL
Cryo + turbo
– 4600l/s
Page 18
Chamber pumping and base pressure
The Business of Science®
Which type of pump do you need?
Depends on:
• Process gases to be used at process pressure
• cryo cannot pump H2, He, etc. Heavy gases like Xe are better with cryo.
• Required speed of vacuum recovery (from atmosphere)
• cryopump will recover base pressure faster
• Required ultimate vacuum conditions (residual gases, etc.)
EXAMPLES:
• Etch processes using He back-side cooling  needs turbo for process
pumping as cryopumps cannot condense the very light gases ()
• Processes very sensitive to water vapour require cryopump or turbo +
Meisner coil with Polycold, for example
• Base pressure spec <2 x 10-7 Torr, turbo will suffice
• Base pressure spec <7.5 x 10-8 Torr, typically needs cryopumping
• Base pressure spec <5 x 10-8 Torr, typically needs both cryo and turbo
pump  process can then be run with turbo only (e.g. where He flow is
required)
© Oxford Instruments 2016
CONFIDENTIAL
Page 19
Chamber pumping and base pressure
The Business of Science®
Base pressure after bake out at 80C for 5 hours, then cooling for 9 hours
(Ionfab300+ Large Chamber with turbomolecular pump)
• Maglev turbo ATH1600MT, Dry pump Alcatel 122P
© Oxford Instruments 2016
CONFIDENTIAL
Page 20
Chamber pumping and base pressure
The Business of Science®
© Oxford Instruments 2016
CONFIDENTIAL
Page 21
Chamber pumping and base pressure
The Business of Science®
Ion Beam Gas Flows
He BS cooling
Gas ring (CAIBE, Cl2, etc.)
Ar, Kr, Xe
P1
Deposition
Ion Source
+
neutraliser
Reactive Gases
(e.g., O2, N2, etc.)
© Oxford Instruments 2016
Ar, Kr, Xe
Etch/Pre-clean/Assist
Ion Source +
neutraliser
Reactive Gases
(e.g., O2, N2, etc.)
High vacuum
pump
CONFIDENTIAL
Page 22
Chamber pumping and base pressure
The Business of Science®
Process chamber pressure vs gas flow rate
Ionfab300Plus(L/C) process chamber pressure vs
Ar gas flow
-- Base pressure: 5.0 x 10-7 Torr before gas introduction -(1600l/s maglev turbo backed by a 60 m3/h rotary pump)
1.10E-03
1.00E-03
9.00E-04
Pressure (Torr)
8.00E-04
7.00E-04
6.00E-04
-- Base pressure: 5.0 x 10-7 Torr before gas introduction --
5.00E-04
(1600l/s maglev turbo backed by a 60 m3/h rotary pump
+ CTI-10 3000l/s cryopump)
4.00E-04
3.50E-04
3.00E-04
2.00E-04
3.00E-04
1.00E-04
0
2
4
6
8
2.50E-04
10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42
Ar gas flow rate (sccm)
Pressure (Torr)
0.00E+00
2.00E-04
1.50E-04
1.00E-04
5.00E-05
-4.88E-19
0
2
4
6
8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42
Ar gas flow rate (sccm)
© Oxford Instruments 2016
CONFIDENTIAL
Page 23
Chamber pumping and base pressure
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Sources of residual gases:
• Chamber leaks (air)
• always present to a more or lesser extent
• try to minimize in construction (laser welding, no water fittings
exposed to vacuum, etc.)
• Wall/liner outgassing (H2, H2O, air, N2, CO2, H2 …)
• chamber bakeout after pump down from atmosphere
• heat walls during processing  prevents process heating causing
poor reproducibility
• ‘Trapped volume’ outgassing (air, N2, H2O)
• build components (screws, bolts, etc.) should be appropriately
‘vented’
• MFC/gas valve leaks (gas line gases)
• replace MFC or valve
© Oxford Instruments 2016
CONFIDENTIAL
Page 24
Chamber pumping and base pressure
The Business of Science®
RGA comparison scans
Typical pumping scenario with no leaks – turbomolecular pump only
Just after pump down - water high
After a further hour- water low
Cryogenic pumping scenarios
Base pressure – no leaks
Pumping scenario with a leak
© Oxford Instruments 2016
CONFIDENTIAL
Page 25
Chamber pumping and base pressure
The Business of Science®
Base pressure – effects of residual gases
PHYSICAL:
• Ion beam scattering
• Gas inclusion in deposited films
CHEMICAL:
• Oxidation/Nitridation of depositing material
• Reaction with background H2O
• Effects on etch processes
•Mask selectivity, surface effects on etched material,
etch profiles, effects on later processing steps
PHYSICO-CHEMICAL:
• Interface effects  Adhesion, stress, growth, surface
oxidation/nitridation
© Oxford Instruments 2016
CONFIDENTIAL
Page 26
Chamber pumping and base pressure
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Measures to reduce background gas and water vapour:
• Make sure all furniture, bolts, screws, etc. have no trapped volumes.
Bake all liners, shields, etc. in an oven before installation in the
chamber
• Chamber wall heating  bakeout at 80C, maintain process
temperature, e.g. 40C
• ‘Water pump’  Meisner coil with Polycold, Cold plate, etc.
(Liquid N2 temperatures) in particular for turbo-pumped
chambers. Cryopumps already serve as water pumps
• Potentially, deposit ‘getter’ material on liners  e.g. Ti
© Oxford Instruments 2016
CONFIDENTIAL
Page 27
Chamber pumping and base pressure
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Chamber wall heating for bakeout
• Electrical heater mats:
• Custom design mats to fit the tool wall shape
• Independent wall temperature controlled, 6 areas
© Oxford Instruments 2016
CONFIDENTIAL
Page 28
Ion Beam Etching
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Rotating/tilting
sample holder
Ar, Xe, Kr…
Types of IB etching:
Etch
Ion
Source
• IB Etch/Milling
 Ar, Xe, Kr
• Reactive IBE (RIBE)
 O2, SF6, CHF3, etc.
Pumping
Reactive Gases
(e.g., O2, SF6, CHF3,
etc.)
• Chemical-Assisted IBE (CAIBE)
 BCl3, Cl2, SiCl4, etc.
© Oxford Instruments 2016
BCl3, Cl2, SiCl4
CONFIDENTIAL
Page 29
Ion Beam Etching
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Inert gas IB etching/milling  Physical removal, presence of reactive (H,
OH, O2, N2…) gases can:
• Reduce selectivity to PR mask
• React with etched material reducing etch rate, affecting
sidewalls/profile, and precision of etch control in general
Reactive IB etching (RIBE/CAIBE)  Physical + chemical removal,
presence of reactive gases (H, OH, O2, N2…) can:
• Reduce selectivity to PR mask, and also affect precise control of
selectivity (very important for repeatability in certain applications)
• Change the reaction with etched material modifying etch rate,
affecting sidewalls/profile, and precision of etch control in general
© Oxford Instruments 2016
CONFIDENTIAL
Page 30
Ion Beam (Sputter) Deposition
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Rotating/tilting
sample holder
Sputter gases (Ar,
Xe, Kr)
Types of Deposition:
• IBD or IBSD or DIBS
Assist/Pre
-clean Ion
Source
Deposition
Ion Source
Reactive gases
(e.g., O2, N2, etc.)
• Ion-Assisted IBD
• Reactive IBD
© Oxford Instruments 2016
Assist/Pre-clean
gases (Ar, Xe, Kr)
Reactive gases
(e.g., O2, etc.)
CONFIDENTIAL
Pumping
Rotating/indexable
target holder
Page 31
Ion Beam (Sputter) Deposition
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Film properties to consider for deposition:
•
•
•
•
•
Adhesion  residual gas adsorbed on surfaces
Stress  residual gas adsorbed on surfaces
Stoichiometry  residual gas combines chemically with depositing species
Density  residual gas included in film
Optical properties  residual gas combines chemically with depositing species or
included in film
• Refractive Index
• Absorption
• Electrical/magnetic properties  residual gas combines chemically with depositing
species or included in film
•
•
•
•
Resistivity
Dielectric constant
Permittivity/permeability/coercivity
MR ratio (magneto-resistive sensors, MRAM, HDD read/write heads…)
© Oxford Instruments 2016
CONFIDENTIAL
Page 32
Examples of customer processes
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Comments from a user of IB etch and deposition in opto-electronics:
Vacuum quality strongly influences etch selectivity. Air leaks, water leaks or
oxygen/nitrogen leaks (e.g. gas line valve leaks) increases etch rate of polymers
and reduces rate of many metals during etch
Hence, the effect of lower etch selectivity is generated twice in the case of a poor
vacuum.
As an example, in the case of very high resolution pattern working with thin resist
mask and a few tens of nanometers Cr, pattern transfer with correct critical
dimensions may fail.
Deposition quality also depends on residual gas pressure. For pure reactive metals (Cr,
Al, Ti, W, etc.) the presence of background oxygen or nitrogen may increase electrical
resistance and decrease etch rate. Deposited material contains reaction products with
residual gases which are mostly more resistant to IBE …
Deposition (RIBD) of oxides and nitrides for micro-optics needs stable conditions.
Residual gas may influence refraction index, absorption of light, spectral operation range,
light induced conductivity (plasmonics, etc.)
© Oxford Instruments 2016
CONFIDENTIAL
Page 33
Application examples
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Deposition:
[main effects of poor vacuum quality  stoichiometry, process repeatabiliy]
• Vanadium oxide (VOx) deposition for uncooled bolometer and infrared
sensor applications
• Magnetic multilayers for MRAM and GMR sensor applications
• Highly reflective and/or highly conductive Al films for various applications
• Ti in Ti/Pt/Au contact stack  any O2 can easily oxidize Ti and affect
resistivity, O2 at interface can affect adhesion and stress (this layer is used
as an interface for the Au conducting layer in contacts for semiconductor
diodes
• ITO – and other transparent conductive oxides  very sensitive to
background O2
• sp2/sp3 (graphite/diamond) ratio in amorphous carbon
deposition (dependent on N2 in background). O2 needs to be eliminated as
much as possible
© Oxford Instruments 2016
CONFIDENTIAL
Page 34
Ion beam deposition of VOx
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VOx deposition can use Assist/Pre-clean
Resistivity (Ohm/Sq)
dielectric
Desired resisitivity
High TCR
metal
O2 flow sccm
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Example of
TCR=-2.4%
(for 50nm,
~1M/ film)
Т [C]
20 25 30 35 40 45 50 55 60 65 70
• Requires very accurate control of O2 partial pressure  High-pressure
•
•
•
RGA with closed-loop control of O2 flow
Typical film thickness  50nm – 100nm
Typical targeted sheet resistance  50K/ - >1M/
Background/residual O2/N2 very important for TCR and repeatability
© Oxford Instruments 2016
CONFIDENTIAL
Page 35
GMR sensors or MRAM
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Spin-valve
Current
or
Magnetic Tunnel Junction
Current
Thickness nm
~5.0
~10.0
~2.0
~0.6
~2.0
Cu for spin-valve (~2.5nm) or MgO/Al2O3 for MTJ(1-2nm)
~1.0
~2.0
~3.0
These interfaces
are particularly
sensitive to the
vacuum
environment and
background
species, especially
O2
Requires base pressures in mid 10-8 Torr range with low water vapour
(cryo or water pump)
© Oxford Instruments 2016
CONFIDENTIAL
Page 36
Aluminium deposition - reflectance
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Base pressure
should ideally
be in 10-8 Torr
range
© Oxford Instruments 2016
CONFIDENTIAL
Page 37
Customer applications on Ionfab300
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Etch application examples -
• Control of Ti and Cr metal layer etch in multilayer etches for
•
sensor devices:
• Control of selectivity to PR mask is crucial to stop the etch
in the thin metal layer
• Variable amounts of background O2 can affect the
repeatability of the process in production system
Optical components (lenses, etc.) fabricated by pattern
transfer through differential etching of PR on CaF2
• Control of selectivity to PR mask is crucial for a faithful
transfer of the PR pattern into the CaF2
• As above, variable amounts of background O2 can affect
the repeatability of the process in production system
resulting in diffractive lenses going out of tolerance…
© Oxford Instruments 2016
CONFIDENTIAL
Page 38
Selectivity in PR pattern transfer
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Etch beam
0.80
PR
0.78
CaF2
0.76
Selecetivity CaF2/PR
Selectivity CaF2 /PR vs O2 Flow
Ar etch source flow = 12sccm
0.74
0.72
0.70
1.400
0.68
1.300
0.66
1.200
0.64
1.100
0.62
1.000
0.60
1.0
0.900
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0
0.800
0.700
0.600
0.500
0.400
0.300
0.200
0.100
0.000
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
O2 Flow
© Oxford Instruments 2016
CONFIDENTIAL
Page 39
Application example
– Deposition + Etching in DIBS tool
The Business of Science®
Uses OS endpoint to control Cr etch
• High-resolution patterning of IB deposited Cr:
•
•
•
the depositing Cr can react with residual background gases (O2, N2) producing films
that are harder to etch (lower etch rate)
selectivity to PR is crucial in a fine patterning with a thin PR layer for small CD on IB
deposited Cr (tens of nm thickness)
higher etch rate of PR due to background O2 + lower etch rate of Cr = lower
selectivity and potential failure of patter transfer!
Cr with 200nm period grating
courtesy J. Fuchs, Jena
© Oxford Instruments 2016
CONFIDENTIAL
Page 40
Reactive ion beam etching
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RIBE  reactive gas injected into the source with inert gas
• SiO2, Si3N4, LiNbO3 with CHF3
SiO2 with Cr mask
LiNbO3 with SU8 mask
CF4, CHF3, Cl2… directly into the source
(+Ar or Xe…)
Si3N4 with photoresist mask
© Oxford Instruments 2016
CONFIDENTIAL
Page 41
Chemically-assisted ion beam etching
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CAIBE  reactive gas injected right at the substrate
• GaAs with SiO2 mask with Cl2
• InP with SiO2 mask with hot Cl2 (300oC)
1m
10m
Ex: Cl2 through gas ring
Ar through etch source
© Oxford Instruments 2016
400nm
GaAs ER=86nm.min-1
GaAs ER=61.4nm.min-1
GaAs ER=45nm.min-1
GaAs etched=3.8m
GaAs etched=2.7m
GaAs etched=2m
S=15
S=11
S=8.4
=85
=86.5 average
=84.7 average
GaAs with SiO2 mask
CONFIDENTIAL
Page 42
Ion beam etching with SIMS
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Endpoint detection and etch control
© Oxford Instruments 2016
CONFIDENTIAL
Page 43
Ion beam etching with SIMS
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IBE of MRAM with SIMS probe
Sample:
• 1 by 1 square cm
SEM (C/S)
SIMS detection of a multilayer stack-Min4
400000
350000
300000
250000
200000
150000
100000
50000
0
00:00
4” Si wafer
Sample location
01:26
02:53
Courtesy University TU TWENTE
04:19
05:46
07:12
08:38
Time (min, sec)
Ta(5nm)/Co(15nm)/Al2Ox(2.3nm)/Co(3.5nm)/FeMn(10nm)/Co(5nm)/Ta(5nm) /SiO2(2mm) (substrate)
•
Slow controlled etch that enables thin multilayer stack to be monitored with SIMS
© Oxford Instruments 2016
CONFIDENTIAL
Page 44
Ionfab for optical multilayer coatings
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• Typical laser bar fixture carrier to fit into the highspeed substrate holder with built-in white-light or
laser optical endpoint monitor.
• The pre-clean/assist source illuminating the
substrate is flush with the mounting door in this
configuration
© Oxford Instruments 2016
CONFIDENTIAL
Page 45
Deposition Performance – Ta2O5
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Ta2O5 - Uniformity over 8"
175
Layer Thickness [nm]
174
Run 1
173
Run 2
Run 3
Run 4
172
Run 5
171
170
8" Wafer Diameter
© Oxford Instruments 2016
5 consecutive Runs
Layer Thickness Uniformity
Refractive Index Uniformity
Run 1
± 0,610%
± 0,0460%
Run 2
± 0,609%
± 0,0368%
Run 3
± 0,600%
± 0,0460%
Run 4
± 0,609%
± 0,0322%
Run 5
± 0,650%
± 0,0368%
Repeatability
± 0,158%
± 0,0205%
CONFIDENTIAL
Page 46
Ion beam deposition – ultra-smooth films
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(IBD) laser bar facet coating
• Ion Beam Deposition
• Minimal Surface Roughness / Scattering
• < 0.05 nm RMS
© Oxford Instruments 2016
CONFIDENTIAL
Page 47
CONCLUSION
The Business of Science®
• Ion beam deposition and etching operates at low pressures
compared with other thin film processes
• This allows high-precision and excellent quality films to be
deposited and precision control of etch depth and profiles
• However, in order to achieve this perform, it requires a
relatively high vacuum quality with low levels of residual
gases
• Typical base pressures prior to processing need to be in the
10-7 Torr range with the ultimate base pressure
requirements often in the mid to low 10-8 Torr range
© Oxford Instruments 2016
CONFIDENTIAL
Page 48
Ionfab300 clusterability
The Business of Science®
© Oxford Instruments 2016
CONFIDENTIAL
Page 49