**EVALUATION OF FLEXIBLE LAMINATE**

**PRINTED CIRCUIT BOARDS UNDER**

**WIDE TEMPERATURE CYCLING**

Test Report

Richard Patterson

NASA Glenn Research Center

&

Ahmad Hammoud

QSS Group, Inc.

&

Scott Gerber

ZIN Technologies

NASA Glenn Research Center

Cleveland, Ohio

August 8, 2001

**Evaluation of Flexible Laminate Printed Circuit Boards Under**

**Wide Temperature Cycling**

**Background**

Flexible printed circuit boards constitute one of the key technology
elements required by NASA for successful development of advanced power
and control systems for space applications. The boards have to be
lightweight, reliable, and be able to withstand operation in harsh
environments. Temperature swings, which are typically experienced in
planetary exploration such as Mars, comprise one of such stresses in
these missions.

In a collaborative effort between NASA GRC, LaRC, and JPL under the NASA
Electronic and Packaging Program (NEPP), two different flexible printed
circuit boards were designed and built by NASA LaRC. Each board had a
three-layer structure of insulating material with seven serpentine-like
copper traces sandwiched between them. The first printed circuit board
(board #1) had only polyimide as the main insulation media, while the
insulating material of the other printed circuit board (board #2)
consisted of a mix of polyimide and boron nitride. These boards were
delivered to NASA GRC for in-house evaluation under wide temperature
cycling. Photographs of board #1 and board #2 are shown in Figures 1 and
2, respectively. It is anticipated that the results of these
investigations will help to understand the effects of extreme
temperature exposure on the integrity and the functionality of these
boards, and thereby steps can be taken in the design and construction of
reliable printed circuit boards for operation under wide temperature
ranges.

![](media/image1.jpeg){width="5.997222222222222in"
height="3.997916666666667in"}

Figure 1. Photograph of Board #1.

![](media/image2.jpeg){width="5.997222222222222in"
height="4.007638888888889in"}

Figure 2. Photograph of Board #2.

**Test Procedure and Setup**

The two boards were tested separately as each was subjected to a
different sequence of thermal cycling that was specified by the two NASA
Centers and JPL. The thermal cycle sequence for both boards is listed in
Table I. One complete thermal cycle is defined as exposing the board
under test between +100 °C and --125 °C at a temperature rate of change
of 10 °C/min. A soak time of 10 minutes was allowed at the extreme
temperatures. Prior to any thermal cycling activity, the capacitance and
dissipation factor of all seven serpentine traces of each board were
measured at room temperature (pre-cycling). These dielectric properties
were measured in the frequency range of 200 Hz to 500 kHz. During the
first cycle, these properties were also obtained in‑situ at the extreme
temperatures, i.e. +100 °C and --125 °C. After completion of the first
thermal cycle, the board was checked for changes in physical integrity,
such as delamination, warping, discoloration; and its capacitance and
dissipation factor were measured again (post-cycling). If the board
under test survived the first cycle without any significant changes,
then it was subjected to further cycling according to the sequence
listed in Table I.

Table I. Test sequence for flexible printed circuit boards.

+-----------------------------------+-----------------------------------+
| Board #1                          | Board #2                          |
+-----------------------------------+-----------------------------------+
| Measure capacitance & dissipation | Measure capacitance & dissipation |
| factor (pre-cycling)              | factor (pre-cycling)              |
+-----------------------------------+-----------------------------------+
| Do 1 cycle                        | Do 1 cycle                        |
+-----------------------------------+-----------------------------------+
| > Measure capacitance &           | > Measure capacitance &           |
| > dissipation factor (in-situ);   | > dissipation factor (in-situ);   |
| >                                 | >                                 |
| > Measure capacitance &           | > Measure capacitance &           |
| > dissipation factor              | > dissipation factor              |
| > (post-cycling);                 | > (post-cycling);                 |
| >                                 | >                                 |
| > Check for physical damage       | > Check for physical damage       |
+-----------------------------------+-----------------------------------+
| If intact; do 2 more cycles       | If intact; do 2 more cycles       |
+-----------------------------------+-----------------------------------+
| > Measure capacitance             | > Measure capacitance             |
| > (post-cycling);                 | > (post-cycling);                 |
| >                                 | >                                 |
| > Check for physical damage       | > Check for physical damage       |
+-----------------------------------+-----------------------------------+
| If intact; do 2 more cycles       | If intact; do 1 more cycle        |
+-----------------------------------+-----------------------------------+
| > Measure capacitance             | > Measure capacitance &           |
| > (post-cycling);                 | > dissipation factor (in-situ);   |
| >                                 | >                                 |
| > Check for physical damage       | > Measure capacitance &           |
|                                   | > dissipation factor              |
|                                   | > (post-cycling);                 |
+-----------------------------------+-----------------------------------+
| If intact; do 5 more cycles       | > Check for physical damage       |
+-----------------------------------+-----------------------------------+
| > Measure capacitance             |                                   |
| > (post-cycling);                 |                                   |
| >                                 |                                   |
| > Check for physical damage       |                                   |
+-----------------------------------+-----------------------------------+
| If intact; do 10 more cycles      |                                   |
+-----------------------------------+-----------------------------------+
| > Measure capacitance             |                                   |
| > (post-cycling);                 |                                   |
| >                                 |                                   |
| > Check for physical damage       |                                   |
+-----------------------------------+-----------------------------------+
| If intact; do 1 more cycle        |                                   |
+-----------------------------------+-----------------------------------+
| > Measure capacitance &           |                                   |
| > dissipation factor (in-situ);   |                                   |
| >                                 |                                   |
| > Measure capacitance &           |                                   |
| > dissipation factor              |                                   |
| > (post-cycling);                 |                                   |
| >                                 |                                   |
| > Check for physical damage       |                                   |
+-----------------------------------+-----------------------------------+

Test Results of Board #1

Changes in the capacitance with temperature of the seven serpentine
traces of board #1, which had only polyimide as the insulating material,
during the first thermal cycle are listed in Figures 3 through 9. These
results represent data taken at room temperature, as well as, at 100 °C
and --125 °C. For simplicity, the capacitance values measured at only 1
kHz are reported in these figures. The investigated dielectric
properties, which included both the capacitance and dissipation factor,
were actually obtained in the frequency range of 200 Hz to 500 kHz.
Detailed plots of these data as a function of frequency at different
temperatures are given in Appendix A.

A close examination of Figure 3, which depicts capacitance of trace 1 as
a function of temperature during the first cycle, shows that the
capacitance exhibited an increase as temperature was increased from room
temperature to 100 °C. When the test temperature was lowered to --125
°C, the capacitance decreased to a level below its room temperature
value. There seems to be a somewhat linear relationship between the
capacitance of the metallic trace and the temperature. For example,
while the capacitance increased by about 5 % at 100 °C, it lost about 7
% of its room temperature value when measured at --125 °C. Similar to
trace 1, the other six traces of board #1 have displayed almost an exact
behavior in their capacitance with temperature as can be seen in Figures
4 through 9. The changes experienced in the capacitance of all seven
traces with temperature seem, however, to be transitory in nature as the
capacitance of each trace recovered to its respective room temperature
value after thermal cycling was completed. In addition, no structural
damage was incurred by the board due to this first cycle as no
delamination, breakage, warping, or other physical alteration was
observed.

The board was then subjected to two additional cycles followed by
measurements of its dielectric properties and a full examination of its
physical integrity. Once again, no permanent changes were observed in
its electrical or physical characteristics. In fact, such was the case
even after the additional cycling sequence (a total of 20 cycles) was
completed. The pre-cycling data along with the measured results obtained
in between these cycling runs for the capacitance of all seven traces
are shown in Tables II, III, and IV at a frequency of 1 kHz, 10 kHz, and
100 kHz, respectively. While some variations appear in the measurements
for a given trace, as listed in these tables, they are very minimal and
occur infrequently. These changes are mainly attributed to the parasitic
effects introduced by the wire leads that connect the flexible circuit
board inside the environmental chamber to the external instrumentation.
Instrument accuracy at the very low frequencies and change in the
humidity level, although controlled, might have also played a factor.

At the end of the thermal cycle sequence as listed in Table I, the board
was then subjected to one additional cycle and capacitance measurements
of all seven serpentine traces were taken at 25 °C, 100 °C and --125 °C.
The data obtained during this 21^st^ cycle are plotted and compared to
those of the first cycle in Figures 10 through 16 for trace 1 through
trace 7, respectively. It can be clearly seen that each and every trace
has displayed the same trend in capacitance change with temperature. It
appears that this limited thermal cycling activity, a total of 21 cycles
in the temperature range of 100 °C to --125 °C, produced no effect on
the electrical or physical characteristics of the flexible printed
circuit board #1.

![](media/image3.wmf){width="3.2506944444444446in"
height="2.433333333333333in"}

Figure 3. Capacitance versus temperature for trace 1 of board #1 @ 1
kHz.

![](media/image4.wmf){width="3.2506944444444446in"
height="2.433333333333333in"}

Figure 4. Capacitance versus temperature for trace 2 of board #1 @ 1
kHz.

![](media/image5.wmf){width="3.2506944444444446in"
height="2.433333333333333in"}

Figure 5. Capacitance versus temperature for trace 3 of board #1 @ 1
kHz.

![](media/image6.wmf){width="3.2506944444444446in"
height="2.433333333333333in"}

Figure 6. Capacitance versus temperature for trace 4 of board #1 @ 1
kHz.

![](media/image7.wmf){width="3.2506944444444446in"
height="2.433333333333333in"}

Figure 7. Capacitance versus temperature for trace 5 of board #1 @ 1
kHz.

![](media/image8.wmf){width="3.2506944444444446in"
height="2.433333333333333in"}

Figure 8. Capacitance versus temperature for trace 6 of board #1 @ 1
kHz.

![](media/image9.wmf){width="3.2506944444444446in"
height="2.433333333333333in"}

Figure 9. Capacitance versus temperature for trace 7 of board #1 @ 1
kHz.

Table II. Capacitance (pF) for board #1 at 1 kHz as a function of
thermal cycling.

  ---------- ---------- ------------- ---------- ---------- ---------- ----------
             original   values after                                   
                        consecutive                                    

             value      1 cycle       2 cycles   2 cycles   5 cycles   10 cycles

  Trace 1    105.06     104.92        104.32     105.10     103.73     105.19

  Trace 2    109.94     110.30        108.82     110.15     107.03     110.19

  Trace 3    108.50     108.51        107.90     108.24     106.24     108.09

  Trace 4    119.83     119.69        119.04     118.94     116.95     119.48

  Trace 5    116.94     117.20        117.29     115.95     114.28     115.9

  Trace 6    118.39     117.78        117.39     116.70     114.58     117.07

  Trace 7    110.06     109.55        109.55     108.81     106.35     109.75
  ---------- ---------- ------------- ---------- ---------- ---------- ----------

Table III. Capacitance (pF) for board #1 at 10 kHz as a function of
thermal cycling.

  ---------- ---------- ------------- ---------- ---------- ---------- ----------
             Original   values after                                   
                        consecutive                                    

             value      1 cycle       2 cycles   2 cycles   5 cycles   10 cycles

  Trace 1    103.17     102.84        102.07     102.88     101.35     103.19

  Trace 2    107.77     107.99        106.52     107.94     104.90     108.03

  Trace 3    106.23     106.24        105.39     106.00     103.72     106.07

  Trace 4    117.55     117.47        116.41     116.76     114.70     117.5

  Trace 5    114.97     115.16        114.65     114.01     112.20     114.28

  Trace 6    116.50     115.87        115.17     114.84     112.54     115.43

  Trace 7    108.10     107.50        107.31     106.83     104.48     107.92
  ---------- ---------- ------------- ---------- ---------- ---------- ----------

Table IV. Capacitance (pF) for board #1 at 100 kHz as a function of
thermal cycling.

  ---------- ---------- ------------- ---------- ---------- ---------- ----------
             Original   values after                                   
                        consecutive                                    

             value      1 cycle       2 cycles   2 cycles   5 cycles   10 cycles

  Trace 1    100.98     100.52        99.70      100.56     98.73      100.86

  Trace 2    105.47     105.52        104.10     105.46     102.58     105.6

  Trace 3    103.83     103.77        102.88     103.47     101.06     103.7

  Trace 4    115.16     114.97        113.80     114.25     112.18     115.05

  Trace 5    112.71     112.81        112.04     111.69     109.90     112.09

  Trace 6    114.26     113.59        112.56     112.59     110.12     113.29

  Trace 7    105.78     105.15        104.86     104.53     102.23     105.69
  ---------- ---------- ------------- ---------- ---------- ---------- ----------

![](media/image10.wmf){width="6.697916666666667in"
height="2.5840277777777776in"}

Figure 10. Capacitance versus temperature for trace 1 of board #1 during
initial cycle (a), and after 21 cycles (b).

![](media/image11.wmf){width="6.697916666666667in"
height="2.5840277777777776in"}

Figure 11. Capacitance versus temperature for trace 2 of board #1 during
initial cycle (a), and after 21 cycles (b).

![](media/image12.wmf){width="6.697916666666667in"
height="2.5840277777777776in"}

Figure 12. Capacitance versus temperature for trace 3 of board #1 during
initial cycle (a), and after 21 cycles (b).

![](media/image13.wmf){width="6.697916666666667in"
height="2.5840277777777776in"}

Figure 13. Capacitance versus temperature for trace 4 of board #1 during
initial cycle (a), and after 21 cycles (b).

![](media/image14.wmf){width="6.697916666666667in"
height="2.5840277777777776in"}

Figure 14. Capacitance versus temperature for trace 5 of board #1 during
initial cycle (a), and after 21 cycles (b).

![](media/image15.wmf){width="6.697916666666667in"
height="2.5840277777777776in"}

Figure 15. Capacitance versus temperature for trace 6 of board #1 during
initial cycle (a), and after 21 cycles (b).

![](media/image16.wmf){width="6.697916666666667in"
height="2.5840277777777776in"}

Figure 16. Capacitance versus temperature for trace 7 of board #1 during
initial cycle (a), and after 21 cycles (b).

**Test Results of Board #2**

Changes in the capacitance with temperature of the seven serpentine
traces of board #2, which had polyimide insulation with boron nitride
additive, during the first thermal cycle are listed in Figures 17
through 23. These results represent data taken at room temperature, as
well as, at 100 °C and --125 °C. For simplicity, the capacitance values
measured at only 1 kHz are reported in these figures. As with board #1,
the investigated dielectric properties were obtained in the frequency
range of 200 Hz to 500 kHz. Detailed plots of these data as a function
of frequency at different temperatures are also given in Appendix A.

A close examination of Figure 17, which depicts capacitance of trace 1
as a function of temperature during the first cycle, shows that the
capacitance exhibited an increase of about 3% as temperature was
increased from room temperature to 100 °C. When the test temperature was
lowered to --125 °C, the capacitance decreased by about 8.5% of its room
temperature value. Similar to board #1, there seems to be a somewhat
linear relationship between the capacitance of the metallic trace and
the temperature. All changes in the dielectric properties of this trace
seem to be transitory in nature as they recovered to their original
values after thermal cycling was completed. In addition, the board
experienced no observable damage such as delamination, breakage,
warping, or other physical alteration due to this first thermal cycle.

Similar to trace 1, traces 2, 3 and 4 have displayed almost an exact
behavior in capacitance with temperature as can be seen in Figures 18,
19 and 20, respectively. The remaining three traces; i.e. traces 5-7,
exhibited similar behavior in the dielectric properties with temperature
except their capacitance characteristics at 100 °C, as shown in Figures
21 through 23. Unlike the other traces, the values of their capacitance
did not undergo any appreciable increase when temperature was increased
to 100 °C. It is not really understood why such a trend is observed in
these traces. It is important however to point out that the section of
this board comprising these traces is different from the remainder of
the board containing the other traces. Upon careful examination of the
board as pictured in Figure 2, this section seems to be more cloudy and
opaque. These features, which were apparent on the board prior to any
testing, did not undergo any changes due to thermal cycling.

Board #2 was then subjected to two additional cycles followed by full
examination of its physical integrity and measurements of its
capacitance. Once again, no permanent changes were observed in its
electrical or physical characteristics. The pre-cycling data along with
the measured results obtained after the two thermal cycling runs for the
capacitance of all seven traces are shown in Tables V, VI, and VII at a
frequency of 1 kHz, 10 kHz, and 100 kHz, respectively. Similar to board
#1 results, some variations appear in the reported measurements, but
these variations are very minimal and occur infrequently. As mentioned
before, these changes are mainly attributed to the parasitic effects
introduced by the wire leads, which connect the flexible circuit board
inside the environmental chamber to the external instrumentation, and to
instrument inaccuracy at the very low frequencies.

At the end of the thermal cycle sequence as listed in Table I, the board
was then subjected to one additional cycle and capacitance measurements
of all seven serpentine traces were taken at 25 °C, 100 °C and --125 °C.
The data obtained during this 4^th^ cycle are plotted and compared to
those of the first cycle in Figures 24 through 30 for trace 1 through
trace 7, respectively. It appears that all traces display similar trend
in capacitance with temperature as before. This limited thermal cycling
activity, which comprised of a total of 4 cycles in the temperature
range of 100 °C to --125 °C, produced no effect on the electrical or
physical characteristics of the flexible printed circuit board #2.

![](media/image17.wmf){width="3.247916666666667in" height="2.43125in"}

Figure 17. Capacitance versus temperature for trace 1 of board #2 @ 1
kHz.

![](media/image18.wmf){width="3.247916666666667in" height="2.43125in"}

Figure 18. Capacitance versus temperature for trace 2 of board #2 @ 1
kHz.

![](media/image19.wmf){width="3.247916666666667in" height="2.43125in"}

Figure 19. Capacitance versus temperature for trace 3 of board #2 @ 1
kHz.

![](media/image20.wmf){width="3.247916666666667in" height="2.43125in"}

Figure 20. Capacitance versus temperature for trace 4 of board #2 @ 1
kHz.

![](media/image21.wmf){width="3.247916666666667in" height="2.43125in"}

Figure 21. Capacitance versus temperature for trace 5 of board #2 @ 1
kHz.

![](media/image22.wmf){width="3.247916666666667in" height="2.43125in"}

Figure 22. Capacitance versus temperature for trace 6 of board #2 @ 1
kHz.

![](media/image23.wmf){width="3.247916666666667in" height="2.43125in"}

Figure 23. Capacitance versus temperature for trace 7 of board #2 @ 1
kHz.

Table V. Capacitance (pF) for board #2 at 1 kHz as a function of thermal
cycling.

  ----------------- ----------------- ----------------- -----------------
                    original          values after      
                                      consecutive       

                    value             1 cycle           2 cycles

  Trace 1           99.98             100.55            99.47

  Trace 2           104.24            104.59            102.08

  Trace 3           98.82             99.05             96.60

  Trace 4           87.74             87.90             85.81

  Trace 5           105.97            107.47            102.54

  Trace 6           103.93            105.39            102.15

  Trace 7           92.66             93.44             91.46
  ----------------- ----------------- ----------------- -----------------

Table VI. Capacitance (pF) for board #2 at 10 kHz as a function of
thermal cycling.

  ----------------- ----------------- ----------------- -----------------
                    original          values after      
                                      consecutive       

                    value             1 cycle           2 cycles

  Trace 1           98.19             98.54             97.85

  Trace 2           102.21            102.49            100.50

  Trace 3           96.90             97.12             95.13

  Trace 4           85.82             85.94             84.11

  Trace 5           104.10            104.82            101.00

  Trace 6           102.09            102.92            100.40

  Trace 7           90.77             91.19             89.57
  ----------------- ----------------- ----------------- -----------------

Table VII. Capacitance (pF) for board #2 at 100 kHz as a function of
thermal cycling.

  ----------------- ----------------- ----------------- -----------------
                    Original          values after      
                                      consecutive       

                    value             1 cycle           2 cycles

  Trace 1           95.98             96.34             95.88

  Trace 2           99.49             100.12            98.48

  Trace 3           94.55             94.82             93.08

  Trace 4           83.54             83.71             82.03

  Trace 5           101.80            102.15            98.99

  Trace 6           99.87             100.40            98.23

  Trace 7           88.56             88.87             87.38
  ----------------- ----------------- ----------------- -----------------

![](media/image24.wmf){width="6.697916666666667in"
height="2.5840277777777776in"}

Figure 24. Capacitance versus temperature for trace 1 of board #2 during
initial cycle (a), and after 4 cycles (b).

![](media/image25.wmf){width="6.697916666666667in"
height="2.5840277777777776in"}

Figure 25. Capacitance versus temperature for trace 2 of board #2 during
initial cycle (a), and after 4 cycles (b).

![](media/image26.wmf){width="6.697916666666667in"
height="2.5840277777777776in"}

Figure 26. Capacitance versus temperature for trace 3 of board #2 during
initial cycle (a), and after 4 cycles (b).

![](media/image27.wmf){width="6.697916666666667in"
height="2.5840277777777776in"}

Figure 27. Capacitance versus temperature for trace 4 of board #2 during
initial cycle (a), and after 4 cycles (b).

![](media/image28.wmf){width="6.697916666666667in"
height="2.5840277777777776in"}

Figure 28. Capacitance versus temperature for trace 5 of board #2 during
initial cycle (a), and after 4 cycles (b).

![](media/image29.wmf){width="6.697916666666667in"
height="2.5840277777777776in"}

Figure 29. Capacitance versus temperature for trace 6 of board #2 during
initial cycle (a), and after 4 cycles (b).

![](media/image30.wmf){width="6.697916666666667in"
height="2.5840277777777776in"}

Figure 30. Capacitance versus temperature for trace 7 of board #2 during
initial cycle (a), and after 4 cycles (b).

**Conclusion**

Two flexible printed circuit boards were characterized in terms of their
dielectric properties and physical structure under thermal cycling in
the temperature range between +100 °C and --125 °C. Each board had a
three-layer structure of insulating material with seven serpentine-like
copper traces sandwiched between them. One board had only polyimide
insulation, while the other contained polyimide/boron nitride. The
results obtained indicate that this limited thermal cycling produced no
permanent effect on the physical integrity and the dielectric properties
of either board. Only temporary changes occur in the capacitance and
dissipation factor of the boards at the extreme temperatures. While the
addition of boron nitride to the polyimide does not have any effect on
the dielectric loss of the insulation; it tends, however, to stabilize
the capacitance at high temperatures. Long term thermal cycling and
aging as well as comprehensive testing are required to fully understand
the behavior of these flexible printed circuit boards under multi‑stress
conditions to determine their suitability for use in extreme temperature
environments.

**Acknowledgments**

This work was performed under the NASA Glenn Research Center GESS
Contract \# NAS3-00145 and the NASA Electronic Parts and Packaging
Program (NEPP).

**Appendix**

Detailed experimental data obtained on the two flexible printed circuit
boards are listed in this appendix. Pre-cycling, in-situ, and
post-cycling measurements of the capacitance and dissipation factor in
the frequency range of 200 Hz to 500 kHz are presented. Measurements of
these properties during the first cycle and the last cycle of the
testing sequence are also shown.

Data pertaining to the seven traces of board #1 are shown for
pre-cycling, in-situ, and post-cycling conditions in Figures A1-A7 for
traces 1-7, respectively. The capacitances as well as the dissipation
factors under these conditions during the first cycle are depicted as a
function of frequency.

Changes in the capacitance and dissipation factor for board #1 as a
function of frequency during the first cycle and the 21^st^ cycle are
plotted in Figures A8-A14 for trace 1-7, respectively. Included are the
measurements taken at room temperature, 100 °C and --125 °C.

Data pertaining to the seven traces of board #2 are shown for
pre-cycling, in-situ, and post-cycling conditions in Figures A15-A21 for
traces 1-7, respectively. The capacitances as well as the dissipation
factors under these conditions during the first cycle are depicted as a
function of frequency.

Changes in the capacitance and dissipation factor for board #2 as a
function of frequency during the first cycle and the 4^th^ cycle are
plotted in Figures A22-A28 for trace 1-7, respectively. Included are the
measurements taken at room temperature, 100 °C and --125 °C.

![](media/image31.wmf){width="6.786111111111111in"
height="2.4319444444444445in"}

Figure A1. Capacitance and dissipation factor of trace 1 of board #1 as
a function of frequency.

![](media/image32.wmf){width="6.786111111111111in"
height="2.4319444444444445in"}

Figure A2. Capacitance and dissipation factor of trace 2 of board #1 as
a function of frequency.

![](media/image33.wmf){width="6.786111111111111in"
height="2.4319444444444445in"}

Figure A3. Capacitance and dissipation factor of trace 3 of board #1 as
a function of frequency.

![](media/image34.wmf){width="6.786111111111111in"
height="2.4319444444444445in"}

Figure A4. Capacitance and dissipation factor of trace 4 of board #1 as
a function of frequency.

![](media/image35.wmf){width="6.786111111111111in"
height="2.4319444444444445in"}

Figure A5. Capacitance and dissipation factor of trace 5 of board #1 as
a function of frequency.

![](media/image36.wmf){width="6.786111111111111in"
height="2.4319444444444445in"}

Figure A6. Capacitance and dissipation factor of trace 6 of board #1 as
a function of frequency.

![](media/image37.wmf){width="6.786111111111111in"
height="2.4319444444444445in"}

Figure A7. Capacitance and dissipation factor of trace 7 of board #1 as
a function of frequency.

![](media/image38.wmf){width="6.786111111111111in"
height="5.231944444444444in"}

> \(a\) (b)

Figure A8. Dielectric properties of trace 1 of board #1 during initial
cycle (a), and after 21 cycles (b).

![](media/image39.wmf){width="6.786111111111111in"
height="5.231944444444444in"}

> \(a\) (b)

Figure A9. Dielectric properties of trace 2 of board #1 during initial
cycle (a), and after 21 cycles (b).

![](media/image40.wmf){width="6.786111111111111in"
height="5.231944444444444in"}

> \(a\) (b)

Figure A10. Dielectric properties of trace 3 of board #1 during initial
cycle (a), and after 21 cycles (b).

![](media/image41.wmf){width="6.786111111111111in"
height="5.231944444444444in"}

> \(a\) (b)

Figure A11. Dielectric properties of trace 4 of board #1 during initial
cycle (a), and after 21 cycles (b).

![](media/image42.wmf){width="6.786111111111111in"
height="5.231944444444444in"}

> \(a\) (b)

Figure A12. Dielectric properties of trace 5 of board #1 during initial
cycle (a), and after 21 cycles (b).

![](media/image43.wmf){width="6.786111111111111in"
height="5.231944444444444in"}

> \(a\) (b)

Figure A13. Dielectric properties of trace 6 of board #1 during initial
cycle (a), and after 21 cycles (b).

![](media/image44.wmf){width="6.786111111111111in"
height="5.231944444444444in"}

> \(a\) (b)

Figure A14. Dielectric properties of trace 7 of board #1 during initial
cycle (a), and after 21 cycles (b).

![](media/image45.wmf){width="6.786111111111111in"
height="2.4319444444444445in"}

Figure A15. Capacitance and dissipation factor of trace 1 of board #2 as
a function of frequency.

![](media/image46.wmf){width="6.786111111111111in"
height="2.4319444444444445in"}

Figure A16. Capacitance and dissipation factor of trace 2 of board #2 as
a function of frequency.

![](media/image47.wmf){width="6.786111111111111in"
height="2.4319444444444445in"}

Figure A17. Capacitance and dissipation factor of trace 3 of board #2 as
a function of frequency.

![](media/image48.wmf){width="6.786111111111111in"
height="2.4319444444444445in"}

Figure A18. Capacitance and dissipation factor of trace 4 of board #2 as
a function of frequency.

![](media/image49.wmf){width="6.786111111111111in"
height="2.4319444444444445in"}

Figure A19. Capacitance and dissipation factor of trace 5 of board #2 as
a function of frequency.

![](media/image50.wmf){width="6.786111111111111in"
height="2.4319444444444445in"}

Figure A20. Capacitance and dissipation factor of trace 6 of board #2 as
a function of frequency.

![](media/image51.wmf){width="6.784027777777778in"
height="2.4319444444444445in"}

Figure A21. Capacitance and dissipation factor of trace 7 of board #2 as
a function of frequency.

![](media/image52.wmf){width="6.786111111111111in"
height="5.231944444444444in"}

> \(a\) (b)

Figure A22. Dielectric properties of trace 1 of board #2 during initial
cycle (a), and after 4 cycles (b).

![](media/image53.wmf){width="6.786111111111111in"
height="5.231944444444444in"}

> \(a\) (b)

Figure A23. Dielectric properties of trace 2 of board #2 during initial
cycle (a), and after 4 cycles (b).

![](media/image54.wmf){width="6.786111111111111in"
height="5.231944444444444in"}

> \(a\) (b)

Figure A24. Dielectric properties of trace 3 of board #2 during initial
cycle (a), and after 4 cycles (b).

![](media/image55.wmf){width="6.786111111111111in"
height="5.231944444444444in"}

> \(a\) (b)

Figure A25. Dielectric properties of trace 4 of board #2 during initial
cycle (a), and after 4 cycles (b).

![](media/image56.wmf){width="6.786111111111111in"
height="5.231944444444444in"}

> \(a\) (b)

Figure A26. Dielectric properties of trace 5 of board #2 during initial
cycle (a), and after 4 cycles (b).

![](media/image57.wmf){width="6.786111111111111in"
height="5.231944444444444in"}

> \(a\) (b)

Figure A27. Dielectric properties of trace 6 of board #2 during initial
cycle (a), and after 4 cycles (b).

![](media/image58.wmf){width="6.786111111111111in"
height="5.231944444444444in"}

> \(a\) (b)

Figure A28. Dielectric properties of trace 7 of board #2 during initial
cycle (a), and after 4 cycles (b).