semilab technologies for 450mm wafer metrology
TRANSCRIPT
Sem iconductor Physics Laboratory Co. Ltd. 1
Semilab Technologies for Semilab Technologies for 450mm Wafer Metrology450mm Wafer Metrology
Tibor PavelkaSemilab Semiconductor Physics
Laboratory Co. Ltd.
Sem iconductor Physics Laboratory Co. Ltd. 2
OutlineOutline•
Short introduction to Semilab
•
Technologies with potential for 450mm–
Non-destructive, capable of in-
line process control
•
Contamination monitoring•
Epi layer monitoring•
Implant monitoring•
Dielectric characterization•
Metal layer characterization•
Characterization of etched structures
–
Destructive / analytical tools
Sem iconductor Physics Laboratory Co. Ltd. 3
Short Introduction Short Introduction ––
Semilab FactsSemilab Facts•
Main activity: Development, manufacturing and marketing of metrology equipment for the semiconductor and photovoltaic industries.
•
Revenue exceeds $ 50 million (2008)•
Employees: 258
worldwide, 152
in Hungary •
Laboratory, office and manufacturing space: 11,000 m2,
about 3,000 m2
in the US •
76
physicists employed (43
in Hungary)•
25 employees
holding a
Ph. D.
in physics
(5
in Hungary)
•
Installed
base: more than 2,300 units•
Patents: wholly owned –
90, applications –
8, lincensed –
41•
Listed as 35th
among the 50 fastest growing Central-
East
European
technology companies (Deloitte) in 2008
Sem iconductor Physics Laboratory Co. Ltd. 4
History of SemilabHistory of Semilab
Sem iconductor Physics Laboratory Co. Ltd. 5
History of the Semilab GroupHistory of the Semilab Group1990
2004
2008
2008
2008
2009
2009
Sem iconductor Physics Laboratory Co. Ltd. 6
Semilab around the WorldSemilab around the World
Sem iconductor Physics Laboratory Co. Ltd. 7
Semilab PeopleSemilab People
Hungary59%
UK
Germany1%
SingaporeChina
6%
Japan5%
France6%
USA23%
PhD10%
PhDstudents
3%
University/College
without PhD59%
Other28%
Administrative11%
Engineers35%Physicists
29%
Manufacturing & Assembly
24%
Others1%
Semilab Worldwide Qualifications
Tasks
Sem iconductor Physics Laboratory Co. Ltd. 8
Semilab in European CooperationsSemilab in European Cooperations
•
Successful participation in the SEA-NET project–
MetalMap: lifetime monitoring and metal contamination measurement on bare wafers
–
Lead It: contactless sheet resistance measurement via junction photo-voltage technique
•
Member of the EEMI450•
Participant in other projects under development or evaluation
•
Becoming an active player in European cooperation
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Contamination Monitoring I. Contamination Monitoring I. –– Lifetime Measurement (Lifetime Measurement (μμ--PCD)PCD)
•
Minority charge carrier lifetime: effective parameter
to characterize the purity of semiconductor material
•
μ-PCD method: simple, robust, powerful technique for lifetime monitoring
•
Available in WT wafer testers (from bench-top platform to fully automated 300mm tool)
•
Possible application in 450mm lines
τbulk
Thermal
equilibrium
Excitation
(generation of excess
charge carriers)
Redistribution
of carriers
diffusion of carriers
to the surface
surface
recombination
bulk
recombination
τsurfaceτdiff
surfdiffbulkmeas
111ττττ +
+=
S2d
Dd
pn,2
2
⋅=
⋅=
surf
diff
τ
τπ
D: diffusion constant of minority carriersd: wafer thicknessS: Surface recombination velocity
τmeas
: measured lifetimeτsurface
: surface recombination lifetimeτdiff
: characteristic time for diffusion to the surface from the bulkτbulk
: bulk recombination lifetime
Sem iconductor Physics Laboratory Co. Ltd. 10
Contamination Monitoring II. Contamination Monitoring II. ––
SPV SPV Diffusion Length MeasurementDiffusion Length Measurement
•
Diffusion length: key parameter for semiconductor characterization, especially for metal contamination monitoring
•
Fast, non-contact, non-destructive whole wafer mapping
•
Measurement principle:–
Excess charge carrier pairs are generated by laser pulse → surface photovoltage appears
–
VSPV
~Δn, VSPV
: measured surface photovoltage, Δn: number of excess charge carriers
–
Measurement with different lasers–
The following equation is fulfilled:
–
Φ: photon flux density–
L: diffusion lengtjh–
1/α: penetration depth
1/ [µm]α1/α(1) 1/α(2)L [µm]
VSPV
Φ( )
( )
1
1VSPV
Φ( )
( )
2
2VSPV
SPV Plot
Integrated SPV Measuring Unit
ComputerSPV
electronics
Lock-indetection
Lasers
Capacitive sensor
Silicon wafer
Periodicexcitation
⎟⎠⎞
⎜⎝⎛ +⋅=
Φα1LC
VSPV
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Epi Layer Monitoring I. Epi Layer Monitoring I. ––
Dopant and Dopant and Resistivity Profiling by Airgap CVResistivity Profiling by Airgap CV
•
EPIMET –
real-time, non-contact, non-
destructive production line control for epi processes
•
No need for monitor wafers
•
Pre-treatment is integrated
•
Resistivity and dopant profile plotting
•
Wafer mapping•
Excellent repeatability (<1%) in the range of 1 –
100 Ωcm
LED
bellowsair filter material
guardelectrode
silicon waferwafer vacuum chuck
air bearing
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Epi Layer Monitoring II. Epi Layer Monitoring II. ––
Surface Surface Charge ProfilingCharge Profiling
•
Measurement of n/p, n/n, p/p, p/n epi even over buried layers
•
Measures–
Doping concentration
–
Resistivity–
Depletion layer width–
Surface recombination lifetime
–
Conductivity type•
Based on high frequency AC surface photo-voltage
Illumination
~~~~Wd
δVs ∝ Wd
hν
e
h
Re
Rh
Dark
Bulk
p-type
hν
High frequency surface photo-voltageLow intensity: δ
Vs
< 0.05 kT/qWavelength < 400 nm
δ
Vs
~Wd
~1/Csc
Wd-inv = ƒ(Nsc)
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Epi Layer Monitoring III. Epi Layer Monitoring III. ––
Fast Fast GateGate
•
Non-penetrating Elastic Metal probe for rapid monitoring of epi layers
•
EM-probe: non-
destructive probe for capacitance measurements and IV-profiling
•
Small tip diameter to enable sheet resistance profiling
•
CV profiling
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Implant Monitoring I. Implant Monitoring I. ––
Carrier Carrier IlluminationIllumination
•
In-line, non-contact, pre-anneal monitoring of–
Implant Dose–
PAI depth–
Junction depth•
BX-3000 Carrier Illumination Technology–
Generation laser creates excess carriers
–
Excess carriers gradient forms index of refraction gradient
–
Probe laser reads out index of refraction to determine junction properties
Objective lens
Generation laser(830 nm red)
Probe laser(980 nm IR)
Beam splitter
CognexPatMaxVision system
Detector
Deep
Shallow
BX-10 Xj
measured contour
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Implant Monitoring II. Implant Monitoring II. ––
Junction Junction PhotoPhoto--VoltageVoltage
•
Control the implant and anneal by measuring sheet resistance (Rs
) of the implanted layer after anneal
•
LED generates charge carriers which spread laterally
•
Spreading is detected capacitively, Rs
is calculated
•
Non-contact, non-
destructive
•
Fast, high resolution mapping
•
Good repeatability•
Good correlation with conventional techniques
•
Works from USJs to deep implants
Si substrate
Junction + ++
LED
Pickup electrodes
0
200
400
600
800
1000
0 200 400 600 800 1000
She
et r.
4pp
[O
hm/s
q.]
JPV Sheet resistance [Ohm/sq.]
Vendor 1
Vendor 2
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Dielectric Characterization I. Dielectric Characterization I. –– Spectroscopic EllipsometrySpectroscopic Ellipsometry
•
GES5E: R&D Spectroscopic Ellipsometer
to meet requirements of emerging technologies
/
materials
•
Measures complex reflectance ratio
•
Parameters: •
Spectral range:–
from 190 nm to 2.5 µm high resolution
and/or fast measurement mode•
Unique combination with further
techniques:
–
Grazing X-Ray Reflectance–
FT Infra-Red Spectroscopic Ellipsometry
up to 33 µm
–
Adsorption, EPA: Ellipsometric
Porosimeter
(EP) at atmospheric pressure
( )Tknferr i
s
p ,,tan =Ψ== ΔρΔΨ cos,tan
Δcos
Ψtan
Wavelength
Sem iconductor Physics Laboratory Co. Ltd. 17
Dielectric Characterization II. Dielectric Characterization II. –– NonNon--Contact MOS CV (VQ) for SiOContact MOS CV (VQ) for SiO22
and Highand High--κκ
•
Non-destructive measurement technique to replace traditional C-V measurements for qualifying oxide or other dielectric along with interface properties
in silicon wafers•
Measured parameters–
Tox
: Electrical oxide thickness
–
Vfb
: Flatband
voltage–
Dit
: Interface state density–
Qm
: Mobile charge–
Vox
: Oxide voltage–
Qeff
: Effective charge–
Etunnel
: Tunneling electric field
–
Vs
: Surface potential–
Vsurf
: Surface voltage–
Vtunnel
: Tunnel voltage•
Hight throughput: complete analysis in 15 minutes
Corona discharge Kelvin Probe
Illumination
VQ curve Tox
map
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Dielectric Characterization III. Dielectric Characterization III. ––
Near Field Near Field Scanning Microwave Microscope for Scanning Microwave Microscope for LowLow--κκ
•
Non-contact microwave technique to measure the dielectric constant of low-k
materials on production wafers
•
Potential unique application: sidewall damage monitoring
•
Near field antenna (10μm tip size << wavelength) at 100nm distance from the sample
•
Resonant frequency depends on sample properties
•
With suitable calibration, from resonant frequency measurements, κ-value can be determined
Sem iconductor Physics Laboratory Co. Ltd. 19
LowLow--κκ
and Metal Layer Characterization and Metal Layer Characterization –– Surface Acoustic WaveSurface Acoustic Wave
•
Non-contact, non-
destructive tool to obtain
–
Layer thickness–
Bilayer thickness–
Material properties (resistivity, grain size)
•
Laser excitation generates acoustic waves which propagate
•
Propagation is monitored, waveform and spectrum is analyzed
1. Dark signal before wave excitation.
2. Wave excitation with striped pattern.
3. Wave motion and diffraction of probe beam to detector.
Waveform and frequency spectrum.
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Characterization of 3D Etched Structures and Characterization of 3D Etched Structures and Threnches Threnches ––
Model Based Infrared ReflectometryModel Based Infrared Reflectometry
•
Thickness, depth, CD, and composition
can be determined
•
Sample is illuminated by IR light
•
Reflections & absorptions from trenches and films determine shape of reflectance spectrum
•
Spectrum is analyzed with a model of the sample structure, and parameters are determined by fitting the model spectrum
Reflectance Spectrum
Interference fringes
Absorption bands
Exp. DataModel Fit
Ref
lect
ance
Wavenumber (cm-1)
Layers of Interest
45°Infrared Light
1.4 –
20 microns
wavelength
Detector
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Destructive / Analytical ToolsDestructive / Analytical Tools•
Potential for 450 mm–
DLTS: Deep Level Transient Spectroscopy for contamination analysis
–
LST: Light Scattering Tomography for bulk microdefect characterization
–
SIRM: Scanning Infrared Microscopy for bulk defect characterization
–
SRP: Sheet Resistance Profiling