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 (optional)
=
test chip 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
design width =
µm
design width (needed for test
structure identification purposes only)
5
which beam?
which fixed-fixed beam on the test
chip, where "first" corresponds to the topmost fixed-fixed
beam in the column or array that has the specified length?
6
magnification =
×
magnification
7
orientation =
0°
90°
other
orientation of the fixed-fixed beam on
the chip
8
calx =
x-calibration factor (for the given magnification)
9
interx
=
µm
maximum field of view (for the given
magnification)
10
σxcal =
µm
one sigma
uncertainty in a ruler
measurement (for the given
magnification)
11
xres
=
µm
resolution
of the interferometer in the
x-direction
12
calz =
z-calibration factor (for the given magnification)
13
cert =
µm
certified value of physical step
height used for calibration
14
σzcal
=
µm
standard deviation of step height
measurements (on double-sided physical step height)
15
zres
=
µm
resolution
of the interferometer in the
z-direction
16
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
17
aligned?
alignment ensured ?
18
leveled?
data leveled ?
19
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
20
x1max
(i.e., x1upper)
=
µm
21
x1min
(i.e., x1lower)
=
µm
(x1min > x1max)
22
x2min
(i.e., x2lower)
=
µm
(x2min > x1min)
23
x2max
(i.e., x2upper)
=
µm
(x2max > x2min)
Table 3 -
INPUTS
(uncalibrated values from Trace
"b")
Notes
24
x1F
=
µm
z1F =
µm
(x1ave
< x1F * calx)
25
x2F
=
µm
z2F
=
µm
(inflection point)
( x1F <
x2F
< x3F )
26
x3F
=
µm
z3F
=
µm
(most deflected point) (
x1S = x3F
; z1S
= z3F
)
27
x2S
=
µm
z2S
=
µm
(inflection point)
28
x3S
=
µm
z3S
=
µm
(
x3S * calx <
x2ave
)(
x1S < x2S
< x3S )
Table 4 -
INPUTS
(uncalibrated values from Trace
"c")
Notes
29
x1F
=
µm
z1F
=
µm
(x1ave
< x1F * calx)
30
x2F
=
µm
z2F
=
µm
(inflection point)(
x1F < x2F
< x3F )
31
x3F
=
µm
z3F
=
µm
(most deflected point)(
x1S = x3F
; z1S = z3F
)
32
x2S
=
µm
z2S
=
µm
(inflection point)
33
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]
(Each of the standard
uncertainty components is
obtained using a Type B
analysis.) 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.
The value
for the design width should be
between 0
µm
and 60
µm.
6.
Is the
magnification appropriate given
the design length ?
7.
Magnifications at or
less than
2.5× shall not be used.
8.
Is 0.95 < calx <
1.05 but not equal to
"1"? If not,
recheck your
x-calibration.
9.
The value for
interxshould be between 0
µm
and 1500
µm.
10.
The value for
σxcal should be between 0
µm
and 4
µm.
11.
The value for
xres should be between 0
µm
and 2.00
µm.
12.
Is 0.95 <
calz < 1.05 but not
equal to "1" ? If not,
recheck your
z-calibration.
13.
The value
for cert should be
greater than 0 µm and less than
25 µm.
14.
The value for
σzcal
should be between 0
µm
and 0.050
µm.
15.
The value
for
zresshould be greater than 0 µm
and less than or equal to 0.005
µm.
16.
The value for
Rtave
should be between 0
µm
and 0.100
µm.
17.
Alignment
has not been ensured.
18.
Data has not
been leveled.
19.
x1minshould be greater
than x1max.
20.
x2minshould be greater
than
x1min.
21.
x2maxshould be greater
than
x2min.
22.
The
calibrated values for
x1minand
x1maxare
greater than 10 µm apart.
23.
The
calibrated values for
x2minand
x2max
are greater
than 10 µm apart.
24.
In Traces
"b," "c," and "d," the value for
s is not the same.
25.
x1ave
should be
< (x1F
* calx) in all
traces.
26.
(x3S
* calx) should be <
x2ave
in all
traces.
27.
In
all traces, make sure (
x1F
< x2F < x3F ).
28.
In
all traces, make sure (
x1S
< x2S < x3S
).
29.
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.
30.
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.
31.
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.
32.
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.
33.
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.
34.
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.