Advanced Implant and Junction Metrology for 45 nm and Beyond · Advanced Implant and Junction...
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Advanced Implant and Junction Metrology for 45 nm and Beyond Alex Salnik Junction Technology Group Meeting, Semicon West 2007, July 19, 2007
Transcript of Advanced Implant and Junction Metrology for 45 nm and Beyond · Advanced Implant and Junction...
Advanced Implant and Junction Metrology for 45 nm and BeyondAlex SalnikJunction Technology Group Meeting, Semicon West 2007, July 19, 2007
2 7/20/2007
Agenda
Therma-Probe®
Advanced Ion Implant Dose Monitoring
USJ Parameter Monitoring
USJ Carrier Depth Profiling
Ion Implant Damage Depth Profiling (concept)
Microscale Imaging
Summary
3 7/20/2007
Therma-Probe®
Intensity modulated “pump” laser beamCW “probe” laser beam
1 µm beam spot size
Carrier plasma- and thermal-waves
∆R/R
Intensity modulated “pump” laser beamCW “probe” laser beam
1 µm beam spot size
Carrier plasma- and thermal-waves
∆R/R
The first non-contact and non-destructive system for ion implant characterization
Thermal Wave unit (TW unit) industry standard for over 20 years
Based on Modulated Optical Reflectance (MOR) technology
Mainstream application is implant dose monitoring
Signal is driven by carrier plasma-and thermal- wave mechanisms
10
100
1000
10000
100000
1E+09 1E+10 1E+11 1E+12 1E+13 1E+14 1E+15 1E+16
1 2 3 4
TW S
igna
l [a.
u]
Dose [ions/cm2]
PlasmaDominated
Plasma-toThermal transition
Thermally dominated
Amorphous Region:
modulatedInterference & self annealing
10
100
1000
10000
100000
1E+09 1E+10 1E+11 1E+12 1E+13 1E+14 1E+15 1E+16
1 2 3 4
10
100
1000
10000
100000
1E+09 1E+10 1E+11 1E+12 1E+13 1E+14 1E+15 1E+16
1 2 3 4
TW S
igna
l [a.
u]
Dose [ions/cm2]
PlasmaDominated
Plasma-toThermal transition
Thermally dominated
Amorphous Region:
modulatedInterference & self annealing
4 7/20/2007
New Performance Capabilities
Monotonic high dose responseGood sensitivity across entire dose range
Unique TW value removes ambiguity
1.1
1.3
1.5
1.7
1.9
2.1
2.3
13.5 14 14.5 15 15.5 16
log (Dose) [cm-2]
log
(TW
Sig
nal)
[a.u
.]As75
+
100 keV
TP630-XP
New Capability
5 7/20/2007
Advanced Ion Implant Dose Monitoring
0.01
0.1
1
10
100
1000
10000
9 10 11 12 13 14 15 16 17 1810 eV
100 eV
1 keV
10 keV
100 keV
1 MeV
10 MeV
Impl
anta
tion
ener
gy
TP-800 Dose Detectability Requirements & Priorities
1
23
45
6
7
8
0.01
0.1
1
10
100
1000
10000
9 10 11 12 13 14 15 16 17 18
Log(Implantation dose), [cm-2]
10 eV
100 eV
1 keV
10 keV
100 keV
1 MeV
10 MeV
Impl
anta
tion
ener
gy
Summary of advanced system performance
Full-dose, full-energy spectrum capability
Wavelength combinations cover dose/energy regions of interest
Radically improved dose detectability (DD)
Flexibility allows for a variety of advanced applications
Advanced Monitoring Range
Key Process spaces
6 7/20/2007
USJ Parameter Monitoring
What is the ideal metrology solution for USJ ?Non-destructive, Non-contact
In-line Product Monitoring (small measurement area)
Fast (high throughput)
Reproducible
Sensitive to Active Dopant
Enables Carrier Depth Profiling
7 7/20/2007
USJ Parameter Monitoring
Junction Depth
• TW signal has cosine dependence on junction depth
• Ambiguity is removed by applying an advanced signal processing algorithm
0 200 400 600 800 1000 1200 1400 1600
0.70
0.75
0.80
0.85
0.90
0.95
1.00
TW s
igna
l [a.
u]
Junction Depth [A]
Experimental data Theoretical
As1E15 cm-2
2-50 keV
0 200 400 600 800 1000 1200 1400 1600
0.70
0.75
0.80
0.85
0.90
0.95
1.00
TW s
igna
l [a.
u]
Junction Depth [A]
Experimental data Theoretical
As1E15 cm-2
2-50 keV
-100 -80 -60 -40 -20 0 20 40 60 80 100-100
-80
-60
-40
-20
0
20
40
60
80
100
X [mm]
Y [m
m]
340
347
354
361
368
374
381
388
395
-100 -80 -60 -40 -20 0 20 40 60 80 100-100
-80
-60
-40
-20
0
20
40
60
80
100
X [mm]
Y [m
m]
-100 -80 -60 -40 -20 0 20 40 60 80 100-100
-80
-60
-40
-20
0
20
40
60
80
100
X [mm]
Y [m
m]
340
347
354
361
368
374
381
388
395
340
347
354
361
368
374
381
388
395
-100 -80 -60 -40 -20 0 20 40 60 80 100-100
-80
-60
-40
-20
0
20
40
60
80
100
X [mm]
Y [m
m]
235
240
245
250
255
260
265
270
275
-100 -80 -60 -40 -20 0 20 40 60 80 100-100
-80
-60
-40
-20
0
20
40
60
80
100
X [mm]
Y [m
m]
-100 -80 -60 -40 -20 0 20 40 60 80 100-100
-80
-60
-40
-20
0
20
40
60
80
100
X [mm]
Y [m
m]
235
240
245
250
255
260
265
270
275
235
240
245
250
255
260
265
270
275
-100 -80 -60 -40 -20 0 20 40 60 80 100-100
-80
-60
-40
-20
0
20
40
60
80
100
X [mm]
Y [m
m]
365
370
375
380
385
390
395
400
405
-100 -80 -60 -40 -20 0 20 40 60 80 100-100
-80
-60
-40
-20
0
20
40
60
80
100
X [mm]
Y [m
m]
-100 -80 -60 -40 -20 0 20 40 60 80 100-100
-80
-60
-40
-20
0
20
40
60
80
100
X [mm]
Y [m
m]
365
370
375
380
385
390
395
400
405
365
370
375
380
385
390
395
400
405
365
370
375
380
385
390
395
400
405
-100 -80 -60 -40 -20 0 20 40 60 80 100-100
-80
-60
-40
-20
0
20
40
60
80
100
X [mm]
Y [m
m]
268
271
274
276
279
282
285
287
290
-100 -80 -60 -40 -20 0 20 40 60 80 100-100
-80
-60
-40
-20
0
20
40
60
80
100
X [mm]
Y [m
m]
-100 -80 -60 -40 -20 0 20 40 60 80 100-100
-80
-60
-40
-20
0
20
40
60
80
100
X [mm]
Y [m
m]
268
271
274
276
279
282
285
287
290
268
271
274
276
279
282
285
287
290
-100 -80 -60 -40 -20 0 20 40 60 80 100-100
-80
-60
-40
-20
0
20
40
60
80
100
X [mm]
Y [m
m]
428
431
434
437
440
443
446
449
452
-100 -80 -60 -40 -20 0 20 40 60 80 100-100
-80
-60
-40
-20
0
20
40
60
80
100
X [mm]
Y [m
m]
-100 -80 -60 -40 -20 0 20 40 60 80 100-100
-80
-60
-40
-20
0
20
40
60
80
100
X [mm]
Y [m
m]
428
431
434
437
440
443
446
449
452
428
431
434
437
440
443
446
449
452
-100 -80 -60 -40 -20 0 20 40 60 80 100-100
-80
-60
-40
-20
0
20
40
60
80
100
X [mm]
Y [m
m]
295
301
308
314
320
326
333
339
345
-100 -80 -60 -40 -20 0 20 40 60 80 100-100
-80
-60
-40
-20
0
20
40
60
80
100
X [mm]
Y [m
m]
-100 -80 -60 -40 -20 0 20 40 60 80 100-100
-80
-60
-40
-20
0
20
40
60
80
100
X [mm]
Y [m
m]
295
301
308
314
320
326
333
339
345
295
301
308
314
320
326
333
339
345
USJ Depth Maps (Å)
8 7/20/2007
USJ Parameter Monitoring
0 100 200 300 400 500 6000
100
200
300
400
500
600
0.2keV - 1e14 0.2keV - 5e14 0.2keV - 1e15 0.5keV - 5e14 R=0.996
SIM
S [A
]
TWI Junction Depth [A]
100 150 200 250 300 350 400 450 500100
150
200
250
300
350
400
450
500
550 0.2keV - 1 x 1014cm-2 0.2keV - 5 x 1014 cm-2 0.2keV - 1 x 1015cm-2 0.5keV - 5 x 1014cm-2
TW S
igna
l [a.
u]
TWI junction depth [A]
• TW signal is correlated to SIMS to obtain USJ depth values
• Good correlation is obtained for all doses and energies.
Junction Depth Correlation
9 7/20/2007
0.064 0.066 0.068 0.070 0.072 0.074
-0.070
-0.068
-0.066
-0.064
-0.062
6.76
6.78
6.80
6.82
6.84
6.86
6.88
6.90
6.92
X [mm]Y
[mm
]
6.76
6.78
6.80
6.82
6.84
6.86
6.88
6.90
6.92
USJ Parameter Monitoring
Junction Abruptness
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
-0.04 -0.02 0 0.02 0.04 0.06 0.08
In-phase, a.u.
Qua
drat
ure,
a.u
.
Sample # 4Abruptness: 10.4 nm/decade
Sample # 3Abruptness: 6.7 nm/decade 6.9
Measurements are performed at two pump-probe beam separations
MOR signal is analyzed in Q-I coordinates
The slope between the two points is calculated
Slope uniquely defines the abruptness
USJ Abruptness Map (nm/dec)
10 7/20/2007
USJ Parameter Monitoring*
Peak Carrier Concentration
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
-0.15 -0.05 0.05 0.15
TW in phase (a.u.)
TW Q
uadr
atur
e (a
.u.)
1E195E19/cm3
3E20
Q
XjXj2Xj1
C1
C2
Q1
Q2
Q
XjXj2Xj1
C1
C2
Q1
Q2
MOR signal is analyzed in Q-I coordinates
Each (Q-I) pair uniquely corresponds to junction depth and a peak carrier concentration (for box-like profiles)
Junction depth and peak carrier concentration values are obtained simultaneously
* In collaboration with IMEC: T. Clarysse, et al. J. Vac. Sci.Techn. B, 24,1139 (2006)
Peak carrier concentration and junction depth are measured simultaneously
11 7/20/2007
USJ Carrier Depth Profiling
Parametric Profile Approximation: USJ Depth (Therma-Probe Measurements)
USJ Abruptness (TP)
Peak Carrier Concentration (TP)
Solving the Forward and Inverse Problems: (in collaboration with T. Clarysse’s group at IMEC)
Experimental Pump-Probe Beam Offset Scans (TP)
Solution to Forward Problem (IMEC)
Inversion of Offset Scans (IMEC, K-T)
12 7/20/2007
USJ Carrier Depth Profiling
1E+17
1E+18
1E+19
1E+20
1E+21
0 100 200 300 400 500
Depth, Å
SIMS
Abruptness
TW
Xj
Npeak
1E+17
1E+18
1E+19
1E+20
1E+21
0 100 200 300 400 500
Depth, Å
SIMS
Abruptness
TW
Xj
Npeak
Approximated Carrier Depth Profile
Three independent USJ parameters define the approximated carrier depth profile
USJ Depth (Xj)
USJ Abruptness
Peak Carrier Concentration (Npeak)
13 7/20/2007
USJ Carrier Depth Profiling*
Relevant dopant depth profile characteristicspeak carrier concentration, junction depth and abruptness
Extension of TP application to completely independent dopant profile measurement (no calibration to SIMS)Begin with simple box-like profiles (CVD layers) to validate approachProceed with more complicated profiles
As junction depth decreases and abruptness increases, profile
approaches that of a single layer
* In collaboration with IMEC: J. Bogdanowicz, INSIGHT 2007 Workshop (Napa, CA)
14 7/20/2007
USJ Carrier Depth Profiling*
box profile model
Depth
actualdopant profile
For box like profiles the signal results from the optical interference of a surface and an interface reflection
The amplitude of the quadrature signal varies cosinusoidally with the junction depth and the cosine amplitude varies with doping
)))(2cos(( int surfsubsurf NNknzNCSignal −+=Simplified Model
* In collaboration with IMEC: J. Bogdanowicz, INSIGHT 2007 Workshop (Napa, CA)
15 7/20/2007
USJ Carrier Depth Profiling*
−0.20 −0.15 −0.10 −0.05 0.00 0.05 0.10 0.15 0.20 0.25 0.300.000
0.005
0.010
0.015
0.020
0.025
0.030
Iso-doping (cm-3)
Iso-Xj (nm)
Plotting Q vs. I demonstrates the ability to directly extract the junction depth and the peak carrier concentration from a single measurement
Unique reconstruction for Xj < 44 nm and N > 5x1018 cm-3.
USJ Depth and Peak Concentration
* In collaboration with IMEC: J. Bogdanowicz, INSIGHT 2007 Workshop (Napa, CA)
16 7/20/2007
USJ Carrier Depth Profiling*
Pump Probe
Simulation of the Excess Carrier Concentration
Measuring signal while separating the pump and probe beams (offset curve) introduces lateral variation of the carrier density
carrier diffusion length increases with decreasing dopant concentration
Extracting arbitrary dopant profile from offset curves using modeling
finite element simulator (FSEM) approach is currently being developed
* In collaboration with IMEC: J. Bogdanowicz, INSIGHT 2007 Workshop (Napa, CA)
17 7/20/2007
Ion Implant Damage Depth Profiling (concept)
Nor
mal
ized
pha
se, d
egre
es
Beam offset, µm
-40
-30
-20
-10
0
10
20
0 0.5 1 1.5 2 2.5
5E112E11
1.1E111.0E112E109E10
5E10-180
-160
-140
-120
-100
-80
-60
-40
-20
0
1.0E+10 1.0E+11 1.0E+12
Dose
(1)
(2)
(3)
(4)(5)
(6)(7)
1
2
3
5
46 7
Phase at zero offset vs dose
Position in insert
Nor
mal
ized
pha
se, d
egre
es
Beam offset, µm
-40
-30
-20
-10
0
10
20
0 0.5 1 1.5 2 2.5
5E112E11
1.1E111.0E112E109E10
5E10-180
-160
-140
-120
-100
-80
-60
-40
-20
0
1.0E+10 1.0E+11 1.0E+12
Dose
(1)
(2)
(3)
(4)(5)
(6)(7)
1
2
3
5
46 7
Phase at zero offset vs dose
Position in insert
Nor
mal
ized
am
plitu
de
Beam offset, µm
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
0 0.5 1 1.5 2 2.5
2E105E11
5E10
2E11
1.1E111.0E119E10
10
100
1000
1.0E+10 1.0E+11 1.0E+12
Dose
(1)
(2)
(3)(4)(5)
(6)
(7)3
4
52
1 67
Amplitude at zero offset vs dose
Position in insert
Nor
mal
ized
am
plitu
de
Beam offset, µm
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
0 0.5 1 1.5 2 2.5
2E105E11
5E10
2E11
1.1E111.0E119E10
10
100
1000
1.0E+10 1.0E+11 1.0E+12
Dose
(1)
(2)
(3)(4)(5)
(6)
(7)3
4
52
1 67
Amplitude at zero offset vs dose
Position in insert
Theoretical model based on the pump-probe offset scans (forward problem)
Plasma- and thermal-wave components
Experimental offset scans performed at different modulation frequencies
Experimental conditions correspond to the maximum of plasma-thermal interference, i.e. highest sensitivity to depth profile variations
Fitting of experimental data and extracting depth profiles
18 7/20/2007
Microscale Imaging
USJ Anneal UniformityB10H14, 1E15 cm-2, 500 eV
716
717
718
719
720
721
722
-150 -100 -50 0 50 100 150Position [mm]
TWin
f Sig
nal
Horizontal
Vertical
Implant UniformityB11, 1E15 cm-2, 500 eV
step and repeat checkerboard signature of laser anneal
signature of spot beam implanter ~ 5 mm features correspond to pitch of raster scanned beam
19 7/20/2007
Summary
Advanced Ion Implant Dose MonitoringFull-dose, full spectrum capability, dose detectability better than 0.1 % (3σ) across the board
USJ Parameters MonitoringSimultaneous measurement of all USJ parameters of interest
Carrier Depth ProfilingReconstruction of active dopant depth profiles, potentially replacing SIMS
Ion Implant Damage Depth Profiling Simultaneous dose/energy and damage depth profiles for implant characterization, microscale imaging
What to Expect From < 45 nm Implant and Junction Metrology ?
