thermoreflectance microscopy and spectroscopy on integrated circuits m. bardoux, c. boué, c....
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Thermoreflectance microscopy and spectroscopy on integrated circuits
M. Bardoux, C. Boué, C. Filloy, D. Fournier, G. Tessier
UPR A005 CNRS, ESPCI, 10 Rue Vauquelin, 75005 Paris
1
Thermoreflectance under visible illumination
Microscope
White lamp
Pow.1: f
CCD
Circuit
4f < 40 Hz
Filter
CCD thermoreflectance imaging
T
R
R= T
Optical measurement of R(at virtually any wavelength)
measurement of T
oR
oRamb
t
oR
I1 I2 I3 I4
I1
I2
I3
I4
Microscope
White lamp
Pow.1: f
CCD
Circuit
4f < 40 Hz
Filter
2 2
1 3 2 40 4
I I I IR
Amplitude
CCD thermoreflectance imaging
R around 10-5
T around 0.1 KResolution 300 nm
Not leaky structures:
125 m
Transistor arrays (ST Microelectronics)
IDS = 0 - 60 mA, F=1 Hz
=518 nm
leaky structures:
13
m125 m
Vertical Cavity Surface Emission Lasers (VCSELs)
Vertical temperature distribution
M Bardoux, ESPCI, S. Bouchoule, A. Bousseksou, LPN
Laser emission(1.5 m)
VCSEL Cleavage
Top view (emission facet) T (°C)Side view (substrate, mirror, active layers)
Bragg mirror
Substrate
Active layers
T (°C)
90 m 250 m
Numerical circuit180 nm technology(TIMA Grenoble)
ThermoreflectanceResolution : 350 nm
80 m
T(K)
• Clock frequency 225 MHz• Lock-in at the repetition frequency of the test vectors (7.5 Hz)
Backside imaging ?
2
Near Infrared thermoreflectance
InGaAsCCD
Thermoreflectance with an InGaAs cameraSi Transparency region
Microscope
White lamp
Pow.1: f
4f < 40 Hz
Non coherent sourceseliminate interference in the substrate
position (microns)50 100 150 200 250
50
100
150
200
250
300
85 90 95 100 105 110 115 120-250
-200
-150
-100
-50
0
50
100
150
200
250
position (microns)
85 90 95 100 105 110 115 120
1400
1500
1600
1700
1800
1900
position (microns)
X50, 0.6N.A. objective Resolution 2 m (Diffraction limit : 1.7 m)
Dissipated power : 500 mW
Near Infrared back side imaging
position (microns)50 100 150 200 250
50
100
150
200
250
300
0.5
1
1.5
2
2.5
x 10-3
R/R
Position (microns)0 10 20 30 40 50 60
10
20
30
40
50
60
70
2
4
6
8
10
12
14
x 10-4
0 10 20 30 40 50 600
0.5
1
1.5x 10
-3
Re
lati
ve
am
pli
tud
e
0 10 20 30 40 50 60
-2
-1
0
1
2
x 10-4
position (microns)
de
riv
ati
ve
Resolution difficult to assess (noisy image)
Average of FWHM : 650 nmEffective N.A. : 1.55
Diffraction limit with a 0.42 N.A. objective: 2.4 m
10 20 30 40 50 60
10
20
30
40
50
60
70
R/R
3
Thermoreflectance and photoreflectance spectroscopy
Circuit
Microscope
Filter
P. Supply 1: F
WhiteLampP. Supply 2:
4F
CCDspectrometer
T
R
Thermo-/photo- reflectance spectroscopy
R and vary sharplydue to interference
Spatial selectivity : a few m Spectral resolution : 1 nm typ.Sensitivity : R/R~ 3.10-5 in 1 min
Compact fibered spectrometer+ focusing lens
Photoreflectance spectroscopy on passive materials
SiO2 (glass)
Heating=10.6 m
Measurement=615 nm
Amplitude R/R
F=0.5 Hz
F=1 Hz
F=3Hz
F=7.5 Hz
1850 m
Sample
Modulated CO2 laser
Microscope
Filter
P. Supply 1: F
WhiteLampP. Supply 2:
4F
CCDspectrometer
Si substrate
SiO2 + gold nanospheres (≈ 4 nm)
Heating=10.6 m
Gold nanospheres in silica (preliminary results)M. Rashidi, B. Palpant, INSP
450 500 550 600 650 700 750-20
-15
-10
-5
0
5x 10
-4
wavelength (nm)
450 500 550 600 650 700 750-20
-15
-10
-5
0
5x 10
-3
wavelength (nm)
Model T=50 KMajid Rashidi, INSP
R/R
R/R
t= 68 nm MeasurementT ≈ 3 K
x10-4
x10-3
Conclusions1 ) Visible thermoreflectance
resolution ≈ 300 nmprecision of calibrated measurement ≈ 5%
2 ) NIR imaging with Solid Immersion Lenses- Resolution : 650 nm at 1.65 nm, effective N.A.: 1.55 - Resolution improvement :
use narrow band illuminationbetter contact SIL / substrate
3) SpectroscopyFast and sensitive R/R~ 3.10-5 in 1 minGood spectral resolution (1 nm)Performance spectrometer dependentR/R~ 5.10-7 should be achievable in 1 min with a 1.5 108 e- well depth.