Martin,

TCE of FR-4 would depend on whether it was difunctional, or multifunctional.
 Your laminate supplier should be able to give you specifics for your
laminate.

Here is something from my reference works.

>From "Surface Mount Technology for PC Board Design", James K. Holloman, Jr:

Properties of epoxy-glass:
Glass transition temperature:  125C
TCE and Y axis: 15 ppm/degreeC
TCE Z axis:  48 ppm/degreeC
Thermal conductance:  0.15 W/M*degreesC at 25 degrees C
Dielectric contant at 1 MH:  4.8

>From "Printed Circuits Handbook", Clyde F. Coombs, Jr:

Table 8.12  Coefficient of Thermal expansion - in inches/degree C x 1E-5
                Lengthwise    Crosswise
FR-2              1.2                2.5
FR-3              1.3                2.5
CEM-1           1.1                1.7
CEM-3           1.0                1.5
FR-6              1.0                1.0
G-10              1.0                1.5
FR-4              1.0                1.5
G-11              1.0                1.5
FR-5              1.0                1.5
GI                  1.0                1.2

This is based on the ASTM D696 test method.  TCE is the change in length per
degree change in temperature.  The coefficient may vary in different
temperature ranges, so the temperature range must be specified.

Doug Pauls
CSL
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