DocumentCode :
3019883
Title :
Wiring statistics and printed wiring board thermal conductivity
Author :
Nelson, Richard D.
Author_Institution :
Teravicta Technol., Austin, TX, USA
fYear :
2001
fDate :
2001
Firstpage :
252
Lastpage :
260
Abstract :
The thermal conductivity of printed wiring boards depends strongly upon the copper content of the signal and power planes. For boards with continuous power and ground planes, it is adequate to use simple lumped conductivities based on the volume percentage of copper. However, nearly order of magnitude errors can occur when this approach is used with boards with discontinuous or significantly perforated power and ground planes. We describe a statistical approach to modeling the copper connectivity in wired signal planes, based on the probability distribution of wire lengths in the X and Y directions. Using this approach, we have constructed finite element models of six-layer printed wiring boards which approximate functional boards with a wide range of wiring density, via density, and power/ground plane perforations. The finite element results show that the connectivity of the wiring, vias, and power/ground planes plays an important role in establishing the board´s average thermal conductivity. Although there is some scatter in the results, due to wiring details, we find that the percentage of copper in the printed wiring board can still be used as an initial indicator of thermal conductivity. We present an empirical fit to the models suitable for design applications
Keywords :
circuit analysis computing; error analysis; finite element analysis; printed circuit design; printed circuits; probability; statistical analysis; thermal conductivity; thermal management (packaging); Cu; Cu volume percentage; average thermal conductivity; continuous ground planes; continuous power planes; copper connectivity; copper content; design applications; discontinuous ground planes; discontinuous power planes; empirical model fit; errors; finite element models; functional boards; lumped conductivities; perforated ground planes; perforated power planes; power planes; power/ground plane connectivity; power/ground plane perforations; printed wiring board thermal conductivity; printed wiring boards; probability distribution; signal planes; six-layer printed wiring boards; statistical modeling; thermal conductivity; via connectivity; via density; wire lengths; wired signal planes; wiring connectivity; wiring density; wiring statistics; Copper; Finite element methods; Heat transfer; Packaging; Probability distribution; Scattering; Statistics; Thermal conductivity; Wire; Wiring;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Semiconductor Thermal Measurement and Management, 2001. Seventeenth Annual IEEE Symposium
Conference_Location :
San Jose, CA
Print_ISBN :
0-7803-6649-2
Type :
conf
DOI :
10.1109/STHERM.2001.915186
Filename :
915186
Link To Document :
بازگشت