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Institut fr
Produktionsmesstechnik,
Werkstoffe und O tik
pa a y eso ve e erm na on o ressin Thin Films and Devices
from X-ray Curvature Measurements
Nikolaus Herres
Interstaatliche Hochschule fr Technik Buchs NTBWerdenbergstrasse 4, CH-9471 Buchs (SG), Switzerland
. .
Denver X-ray Conference
Colorado Springs (USA), 31 July 2009
1
Session on High Resolution XRD
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8n
ion
]x
4
6sapphireInN
GaN
AlN
alexpans
i
x10-3]
alexpan
s
[x10-3]
ex
Si1
-x[nm
2
lativ
ether
a/a
elat
ivether
a/a
ckn
essof
0 200 400 600 800 1000re
temperature T [C]
temperature T [C]
r
Germanium fraction x
thi
2
( ... ) impaired thermal and mechanical contacts and cracks ( ... )
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F
... in thick films: F = (1 / R) [(ES h3 - EF t
3) / (6t (t + h))]
with F = film stress (in-plane)R = radius of substrate curvature
h
t S, F
where ES = ESubstrate / (1-Substrate)
= Poisson ratios (direction dependent)
R2R1
= c ness o e su s ra e
t = thickness of the film
... in thin films: F = (1 / R) [ES h2/ (6 t)] (Stoney equation)
3
Film stress is calculated from sample curvature and material parameters
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samplesample
HRXRDprimary beammonochromator
mirror
(translation stage)
sx
primary beammonochomator
mirror
n = 2d sin d/d =
X
X-ray source
slitslit
X-ray source
Bragg peak of film is scanned (,2)
x
2
R s /
s
/R x detectordetector
= g - eso u on -ray rac ome ry
XRCA = X-ray Curvature Analysis Bragg peak of substrate is
4
,
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- HRXRD - - XRCA -
compressive tensile
compressive
I
tensile
s mmx mm e .SFFilm
Subst
[]
= 0.001; = 33 = 3 x 10-5
= 0.001; x = 35 mm R = 2000 m
-
5
ESilicon, =130 GPa = 4 MPa h = 500 m; t = 1 m; ESi, = 4 MPa
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3 4
22,660
22,665 after deposition
before deposition[]
500 m GaAs
190 nm Si3N4
22 650
22,655
imum
22,645
film is under compressive straina
kmax
0,010
wa er curva ure: = m
film strain: = 64 MPaOPJ/980723
-NH
raggpe
-25 -20 -15 -10 -5 0 5 10 15 20 25
0,000
,
X0807T
.
B
6
position x [mm]
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35,2
34,8peak position
measurementngle[
]
1 m AlNpea pos t on
,
polynomial fita
30
curvature radius[m]
curvature radius
0
10
radiusR
1,0
1,5
2,0
in-plane film stress (compressive)
[GPa]
process optimizationreduced stress :
in-plane (compressive) film stress
-70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70
0,0
0,5
stres .
to < 0.2 GPa
7
position x [mm]position x [mm]
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104 GaAs
]
Scan direction20 nm InGaP
100 nm AlGaAs
70 nm GaAs:Si
2
103
co
unts/
small flat20 nm AlGaAs:Si
90 nm GaAs:C
700 nm GaAs:Si
101
tensity[
measurement spot
6 mm x 0.5 mmlarge flat
500 m GaAs
200 nm AlGaAs
100
/980217-NH
X-ray
i
32 7 32 8 32 9 33 0 33 1 33 2 33 3
10-1
X0247TD.O
PJ
8
incidence angle [deg.]
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x = 75 mm
0.0633,02
33,04
33,06 shift of peak maximum
ax
imum
deg.]
32,98
33,00
pea
k
600
s
Radii:
at center: 50 m1-980212-NH
200
300
400
500 oca ra us o curvature
turera
di
R
[m]
X0658D
-40 -30 -20 -10 0 10 20 30 400
100
cu
rv
Epitaxial Film Structure
9
3 Wafer GaAs(001) Substrate
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before
nominally
unstrained surface to be
checked
10
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after
deformation
x = 100 m
.
strained surface to be
checked
11force
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Measuring-
Y
XIncidence
Angle Chi
X
Lead Frame
incidence angle
versus position31.532.0
32.5
33.0
position[]
small stresslarge stress
31.0
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00
position X [mm]
1.50
curvature radius
versus position0.50
1.00
a
diusR[m]
12
0.00
0.00 1.00 2.00 3.00 4.00
position X [mm]Siemens CT, M. Schuster
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bad chip15.35
le
with micro-crack
15.20
15.25
15.30
nceAn
g
sition[]
15.10
15.15
0 2 4 6 8 10 12
Incid
p
good chip curved,15.20
le]
position X [mm]
u w ou crac
negative slope concave15.00
15.10
nceA
n
sition
[
measurement through
the package using MoK114.80
14.90
0 5 10
Incid
p
13
position X [mm]
Siemens CT, M. Schuster
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1
1,2
X-Ray Reflection10
Curvature Cius
0,4
0,6
0,8
Intensity
5
7,5
Curvature Radius R=1/C
atureRa
d
urvature
0
0,2
48 50 52 54 56
0
2,5
0 1 2 3 4 5 6 7 8dxd
Curv
53,5 1,2
le
Position x
52,0
52,5
53,0
0,6
0,8
1
rmatio
n
enceA
ng
50,5
51,0
51,5
0 1 2 3 4 5 6 7 8
x dx
0
0,2
0,4
0 1 2 3 4 5 6 7 8
convexDef
eakIncid
14
Position x Position x
Siemens CT, M. Schuster
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-
plug-in module with TC 500 CPE (ADC)chip size: 3.5 mm x 3.0 mm
concave curvature, no crackRadius Rx: -1.9 ... -2.6 m
Radius R : -2.1 ... -2.8 m
parallel beam X-ray diffractometer withmultilayer optics and sub-mm spot size
max. deformation (z): 1 m us ng o o pene ra e pac age
XRCA enables the visualization of deformations in 2 dimensions
15AXO Dresden, T. Holz
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-
Sample: Power Device for Automotive Applications
Temperature range: -55 C to +150 C
z[
m]
mation
De
fo
16
Position x [mm]
Siemens CT, M. Schuster / Infineon, P. Alpern
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-
[
m]
ation
Defor
17
Position x [mm]
Siemens CT, M. Schuster / Infineon, P. Alpern
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Comparison of Leadframe Technology
800
]
600
tio
nz[n
200deform
00.0 0.2 0.4 0.6 0.8 1.0 1.2
pos on x mm
X-Ray Curvature Analysis of a chip of size: 0.8 mm x 0.8 mm
Cu leadframe max. deformation: 565 nm
18
NiFe leadframe max. deformation: 74 nm
Siemens CT, M. Schuster
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-
- uses single crystalline substrates as sensors
- shows very high strain sensitivity (d/d < 3 x 10- )
- can be performed with a lateral resolution < 50 m
- does not require measurements prior to film deposition
- will determine stresses in amorphous films (even if the surface is corroded)
- will examine chips through package or module ( cracks, deformations)using MoK or AgK radiation (in combination with multilayer optics)
- can be used to monitor degradation of soldering between chip and
lead frame due to thermal cycling or package effects
19
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Lutz Kirste
Klaus Khler Fraunhofer Institut IAF Freibur D
Ram Ekwal Sah
, ,
Rainer Tilgner Infineon Technologies, Neubiberg (D)
omas o z res en, e enau
August Enzler NTB, Buchs/SG (CH)
20
an you very muc or your a en on
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