Semilab Technologies for 450mm Wafer Metrology

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.


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


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


History of SemilabHistory of Semilab


History of the Semilab GroupHistory of the Semilab Group1990

2004

2008

2008

2008

2009

2009


Semilab around the WorldSemilab around the World


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


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


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


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


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


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)


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


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


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


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


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


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


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.


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


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

Semilab Technologies for 450mm Wafer Metrology

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