Spatially Resolved Determination of Stress in Thin Films and Devices from X-ray Curvature...

7/29/2019 Spatially Resolved Determination of Stress in Thin Films and Devices from X-ray Curvature Measurements (DXC 2009)

1/20

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


2/20

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 ( ... )


3/20

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


4/20

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

,


5/20

- 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


6/20

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]


7/20

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]


8/20

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.]


9/20

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


10/20

before

nominally

unstrained surface to be

checked

10


11/20

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


13/20

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


14/20

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



15/20

-

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


16/20

-

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


17/20

-

[

m]

ation

Defor

17

Position x [mm]

Siemens CT, M. Schuster / Infineon, P. Alpern


18/20

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



19/20

-

- 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


20/20

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

Spatially Resolved Determination of Stress in Thin Films and Devices from X-ray Curvature...

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