View
215
Download
1
Tags:
Embed Size (px)
Citation preview
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.