wafer mapping tools bulk microdefect analyzer for imaging of · wafer mapping tools for high speed,...
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1st RD50 Workshop 1
SEMICONDUCTOR CHARACTERIZATIONSYSTEMS
Wafer Mapping Tools for high speed, high resolution whole wafer mapping of defects and/or contaminants
Deep Level Spectrometer for identification of electrically active point defects
Bulk Microdefect Analyzer for imaging of extended defects (from 20nm to several micron)
1st RD50 Workshop 2
WAFER MAPPING TOOLS
WT-2000 Wafer Testermonitoring defects and contamination both in the bulk and in the surface region of silicon wafers
Applied measurement techniques:
µ-PCD for bulk SiCharge-PCD for bare wafers
EpiTest for epi wafers
Temperature dependent µ-PCD:for Si and compound materials
SPV for bulk Si
Kelvin Probe for oxide characterization
Eddy current for resistivity mapping
LBIC for solar cell characterization
1st RD50 Workshop 3
WT-2000 µ-PCD TOOL
µ-PCD (microwave photoconductive decay) technique for mapping crystal growth andprocess induced defects and heavy metal contamination in bulk silicon wafers
APPLICATIONSCRYSTAL GROWTH DEFECTS
PROCESS INDUCED DEFECTS/Fe MAPPING
Laser
Microwave
wafer
I = I0 e-t/τ Slip lines Oxygen striations OSF ring
Contaminated hot chuck Fe detectionBoat contamination
Fe
Fe
Fe
1st RD50 Workshop 4
WT-2000 SPV TOOL
Surface Photovoltage (SPV) technique for mapping heavy metal contamination and crystaldefects in the bulk silicon wafer
IRON CONCENTRATIONMAPPING
FeSPV µ-PCD
oxygen Fe
12
34
1/α
Φ/VSPV
L
ΦVSPV
= C(L+1/α )
Fe AND O2 MONITORING BYCOMBINED µ-PCD AND SPVTECHNIQUES
Life
time,
µs
0.01
0.1
1
Injection level, 1/cm31.E+11 1.E+13 1.E+15 1.E+17
SPV µ-PCD
Fe-B pairO2 prec.NFe = C ( )
1Lafter
21
Lbefore2
-
1st RD50 Workshop 5
WT-2000 Charge-PCD
Laser
Microwave
waferCharging
Charging1
1τmeas
1τbulk
=1
τdiff τsurf++
Semilab’s patented new surface passivation method applying controlled charge deposition on to the wafer surface during lifetime mapping provides a highly efficient, reproducible and homogeneous surface recombination elimination on bare wafers.
without charging with charging
Surface /interface characterization
Interface recombination velocity map of an oxidized wafer calculated from the lifetime map measured with and without charging on the same wafer
τaverage=15.7 µs τaverage=268 µs
Lifetime map measured
1st RD50 Workshop 6
WT-2000 MCTTEMPERATURE DEPENDENT LIFETIME
Temperature dependent carrier lifetime measurements
50 100 150 200 2500.01
0.1
1
sample 1 sample 2
Temperature [K]
Life
time
[µs]
50 100 150 200 250
0.1
0.2
0.3
0.4
0.5
Temperature [K]
Life
time
[µs]
sample #2sample #4
HgCdTe InSb
Monitoring minority carrier lifetime as a function of temperature in narrow band gapsemiconductors (InSb, HgCdTe, etc.)
Two measurement strategies:• whole wafer mapping at a preselected stabilized temperature
between 85K and 300K• single point lifetime plot as a function of temperature
between 85K and 300K
1st RD50 Workshop 7
WT-2000 EPITEST
Improved µ-PCD (microwave photoconductive decay) technique for the characterizationof recombination processes in epi structures.
Light excitation
Oxide or passivation.
Microwave
Green laser532nm
Epi layer
p+ or n+ substrate
Ssurface
Sinterface
τepi
τsubstrate
Lifetime map Fe concentration map
13.8µs 14.8µs 5 E91/cm3
3 E101/cm3
1st RD50 Workshop 8
WT-2000 V-Q TOOL
Plasma damage monitoring and oxide/interface characterization by non-contact V-Q curve measurement using Kelvin Probe with additional high intensity illumination and controlledcorona charging
Charge
.. .........
... . .
Light/Kelvin probe
Plasma damagemonitoring
by oxide charge mapNon-contact V-Q
Charge, nC/cm2
SP
V,
V
0
0.5
1
-0.5
Theoritical
Dark -corrected bright
0100 100
Tox Electrical oxide thickness
Qeff Effective charge
Vfb Flatband voltage
Vt Threshold voltage
Vox Oxide voltage
Dit Density of interface traps
1st RD50 Workshop 9
WT-2000 RESITIVITY MAPPER
Controlelectronics
High frequency coil
Headheightcontrol
Non-contact whole wafer resistivity mapping based on the eddy current technique for thedetermination of bulk resistivity distribution in silicon wafers
Resistivity map
Single crystal8” CZ wafer
Multi-crystallinePV material
1st RD50 Workshop 10
SIRM-300BULK MICRODEFECT ANALYZER
Non-contact, non-destructive method based on reflection mode confocal microscopyfor detection and analysis of bulk microdefects
Dislocations Stacking fault
laser
beamsplitter
Z scanning
X-Y scanning
detector
wafer
Denuded zone determination
depth
1st RD50 Workshop 11
DLS-83DDEEP LEVEL SPECTROMETER
Detection and identification of trace level of impurities in concentrations down to 109 atoms/cm3
CRYOSTATSIN DIFFERENT TEMPERATURE RANGES
• Closed Cycle He-cryostat from 20K to 300K• LN2 cryostats from 77K to 450K:
simple bath type LN2 cryostatautomatic LN2 cryostat with controlled LN2 flow
SAMPLE HOLDERwith motor driven positioning
in n-type FZ silicon
Cs-Sii-Cs Ps-Ci(1)Vac-Vac
Ps-Ci(2)
P-Vac
Vac-O
Vac-Vac
Vac-?
?
Cs-Oi
C-O-V2
or
Ci
in p-type FZ siliconRadiation defects
Influence of annealingon Fe-B pairs
Fe-B pair
Fe-interstitial
Molybdenum
1st RD50 Workshop 12
MICRO-LBIC
Very high, 1µm resolution mapping capability to measure at low temperaturesMajor application: HgCdTe devices
LBIC=Light Beam Induced Current