Chapter 22 Materials Selection and Design Considerations
Chapter 22 Materials Selection and Design Considerations
Chapter 22 Materials Selection and Design Considerations
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
W1<strong>22</strong> • <strong>Chapter</strong> <strong>22</strong> / <strong>Materials</strong> <strong>Selection</strong> <strong>and</strong> <strong>Design</strong> <strong>Considerations</strong><br />
Table <strong>22</strong>.6 <strong>Design</strong>ations, Compositions, Electrical <strong>and</strong> Thermal Conductivities, <strong>and</strong> Coefficients of Thermal Expansion for Common<br />
IC Leadframe Alloys<br />
Coefficient of<br />
Electrical Thermal Thermal<br />
Conductivity Conductivity Expansion a<br />
Composition (wt%)<br />
Alloy <strong>Design</strong>ation Fe Ni Co Cu Other [10 6 (�-m) �1 ] (W/m-K) [10 �6 (�C) �1 ]<br />
C19400 2.35 Balance 0.03 P, 0.12 Zn, 39.4 260 16.3<br />
0.03 Pb (max)<br />
C19500 1.5 0.8 Balance 0.6 Sn, 0.03 P 29.1 200 16.9<br />
Kovar (ASTM F15) 54 29 17 2.0 17 5.1<br />
Alloy 42 (ASTM F30) 58 42 1.4 12 4.9<br />
a<br />
Coefficient of thermal expansion values are averages measured between 20�C<br />
<strong>and</strong> 300�C.