Data
analysis sheet for residual strain
measurements
Figure
RS.1.1.
Top view of fixed-fixed beam used to
measure residual strain.
To obtain the
following measurements, consult ASTM
standard test method E 2245 entitled
"Standard Test Method for Residual
Strain Measurements of Thin,
Reflecting Films
Using an Optical Interferometer."
date data taken (optional)
=
/
/
identifying
words
(optional) =
instrument
used
(optional) =
fabrication
facility/process
(optional) =
test
chip name/number
(optional) =
filename of 3-D data set
(optional) =
filename of 2-D data traces
(optional) =
Table 1 - Preliminary
ESTIMATES
Description
1
material =
material
2
t =
µm
beam thickness
3
design length =
µm
design
length
4
which beam?
Third
which fixed-fixed beam on the
test chip ?
5
magnification =
×
magnification
6
orientation =
0
90
Other
orientation of the fixed-fixed beam on
the chip
7
calx =
x-calibration factor
(for the given magnification)
8
interx
=
µm
maximum field of view (for the given magnification)
9
σxcal =
µm
one sigma uncertainty in a ruler
measurement (for the given magnification)
10
xres
=
µm
resolution of the interferometer
in the x-direction
11
calz =
z-calibration factor
(for the given magnification)
12
cert =
µm
certified value of physical step height
used for calibration
13
σzcal
=
µm
standard deviation of step height measurements (on
double-sided physical step height)
14
zres
=
µm
resolution of the interferometer
in the z-direction
15
Rtave
=
µm
peak-to-valley roughness of a flat and leveled surface of
the sample material calculated to be the average of three or
more measurements, each measurement of which is taken from a
different 2-D data trace
16
aligned?
alignment ensured ?
17
leveled?
data leveled ?
18
stiction?
Is this fixed-fixed beam
exhibiting stiction ?
(If it is exhibiting stiction, do
not fill out the remainder of
this form.)
Table 2 -
INPUTS
(uncalibrated values from Trace
"a" or "e")
Notes
19
x1max
(i.e., x1upper)
=
µm
20
x1min
(i.e., x1lower)
=
µm
(x1min > x1max)
21
x2min
(i.e., x2lower)
=
µm
(x2min > x1min)
22
x2max
(i.e., x2upper)
=
µm
(x2max > x2min)
Table 3 -
INPUTS
(uncalibrated values from Trace
"b")
Notes
23
x1F
=
µm
z1F =
µm
(x1ave
< x1F * calx)
24
x2F
=
µm
z2F
=
µm
(inflection point)
( x1F <
x2F
< x3F )
25
x3F
=
µm
z3F
=
µm
(most deflected point) (
x1S = x3F
; z1S
= z3F
)
26
x2S
=
µm
z2S
=
µm
(inflection point)
27
x3S
=
µm
z3S
=
µm
(
x3S * calx <
x2ave
)(
x1S < x2S
< x3S )
Table 4 -
INPUTS
(uncalibrated values from Trace
"c")
Notes
28
x1F
=
µm
z1F
=
µm
(x1ave
< x1F *
calx)
29
x2F
=
µm
z2F
=
µm
(inflection point)(
x1F < x2F
< x3F )
30
x3F
=
µm
z3F
=
µm
(most deflected point)(
x1S = x3F
; z1S =
z3F )
31
x2S
=
µm
z2S
=
µm
(inflection point)
32
x3S
=
µm
z3S
=
µm
(
x3S * calx
< x2ave )(
x1S < x2S
< x3S )
Table 5 -
INPUTS
(uncalibrated values from Trace
"d")
AF= µm from Trace "b" w1F= from
Trace "b"
AS=
µm
from Trace "b"
w3S=from Trace "b"
xeF=
µm
from Trace "b"
xeS=
µm
from Trace "b"
εr0
=
× 10-6
from Trace "b"
εr
=× 10-6
from Trace "b"
AF=
µm from Trace "c"
w1F= from Trace "c"
AS=
µm
from Trace "c"
w3S= from Trace "c"
xeF= µm
from Trace "c"
xeS= µm
from Trace "c"
εr0=
× 10-6 from
Trace "c" εr=× 10-6 from
Trace "c"(USE THIS VALUE)
usamp=× 10-6 from
Trace "c"
uW =× 10-6 from two or three traces
uxcal= × 10-6 from
Trace "c" uL=× 10-6
from Trace "c"
uzcal=× 10-6 from
Trace "c"
uzres =× 10-6 from
Trace "c"
uxres =× 10-6 from
Trace "c"
uxresL =× 10-6 from
Trace "c"
uc= SQRT[usamp2
+ uW2
+ uxcal2
+ uL2
+ uzcal2
+ uzres2
+ uxres2
+ uxresL2] uc =× 10-6 from
two or three traces
AF=
µm from Trace "d"
w1F= from
Trace "d"
AS=
µm
from Trace "d"
w3S= from Trace "d"
xeF=
µm
from Trace "d"
xeS= µm
from Trace "d"
εr0
=
× 10-6
from Trace "d"
εr
=× 10-6 from
Trace "d"
Report the results as follows: Since it can be assumed that the
possible estimated values are either approximately uniformly
distributed or Gaussian with approximate standard deviation
uc, the residual strain is believed to lie in the
interval er ±
uc with a level of
confidence of approximately 68 % assuming a Gaussian distribution.
Modify the
input data, given the
information supplied in any
flagged statement below, if
applicable, then recalculate:
1.
Please fill
out the entire form.
2.
The value
for
t should be between
0.000
µm
and 10.000
µm.
3.
The value
for the design length
should be between
0
µm
and 1000
µm.
4.
The measured
value for
L is more than 3ucL
from the design length.
5.
Is the
magnification
appropriate given the
design length ?
6.
Magnifications at or
less than
2.5× shall not be used.
7.
Is 0.95 < calx < 1.05 but
not equal to "1"? If not,
recheck your
x-calibration.
8.
The value for interxshould be
between 0
µm
and 1500
µm.
9.
The value for σxcal should be
between 0
µm
and 4
µm.
10.
The value for xres should be between 0
µm
and 2.00
µm.
11.
Is 0.95 <
calz < 1.05 but
not equal to "1" ? If not,
recheck your
z-calibration.
12.
The value
for cert should be
greater than 0 µm and
less than 25 µm.
13.
The value for
σzcalshould be between 0
µm
and 0.050
µm.
14.
The value
for
zresshould be greater than 0 µm and
less than or equal to 0.005 µm.
15.
The value for
Rtave should be
between 0
µm
and 0.100
µm.
16.
Alignment
has not been ensured.
17.
Data has not
been leveled.
18.
x1minshould be
greater than x1max.
19.
x2minshould be
greater than
x1min.
20.
x2maxshould be
greater than
x2min.
21.
The calibrated values for
x1minand
x1maxare
greater than 10 µm apart.
22.
The calibrated values for
x2minand
x2max
are
greater than 10 µm apart.
23.
In Traces
"b," "c," and "d," the
value for
s is not the same.
24.
x1ave
should be < (x1F
* calx) in all traces.
25.
(x3S * calx)
should be <
x2ave
in all traces.
26.
In
all traces, make sure (
x1F
< x2F < x3F ).
27.
In
all traces, make sure (
x1S
< x2S < x3S ).
28.
For Trace "b," | [(x2F*calx)
− xeF] | =µm. This should be
< 5 µm. If it is not, choose (x2F,
z2F)
such that (x2F
* calx) is closer to
xeF
=
µm.
29.
For Trace "b," | [(x2S*calx)
− xeS] |
=
µm. This should be
< 5 µm. If it is not, choose (x2S,
z2S)
such that (x2S
* calx) is closer to
xeS
=
µm.
30.
For Trace "c," | [(x2F*calx)
− xeF] | =µm. This should be
< 5 µm. If it is not, choose (x2F,
z2F)
such that (x2F
* calx) is closer to
xeF
=
µm.
31.
For Trace "c," | [(x2S*calx)
− xeS] | =µm. This should be
< 5 µm. If it is not, choose (x2S,
z2S)
such that (x2S
* calx) is closer to
xeS
=
µm.
32.
For Trace "d," | [(x2F*calx)
− xeF] | =
µm. This should be
< 5 µm. If it is not, choose (x2F,
z2F)
such that (x2F* calx) is closer to xeF
=
µm.
33.
For Trace "d," | [(x2S*calx)
− xeS] | =
µm. This should be
< 5 µm. If it is not, choose (x2S,
z2S)
such that (x2S
* calx) is closer to xeS
=
µm.