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Title: Powdered thermal transients modeling to compare AlN substitution for BeO

Conference ·
OSTI ID:535625
;  [1]
  1. Ford Motor Company, Dearborn, MI (United States)

Because of the potential reliability benefits of cooler circuits, highly thermally conducting materials are of interest in temperature-critical electronics. Because they have thermal conductivity ({kappa}) higher than that of BeO, recently developed AlN substrate materials are of special interest. Finite element analyses of thermal transients were run with higher and lower AlN thermal values substituted for those of BeO in a representative case: a heat spreader. As steady state conditions are approached, the 3-D finite element model ranks the two AlN`s and BeO in a manner that is consistent with simple analytical estimates: a higher K leads to a lower transistor temperature. Due to less expansion coefficient mismatch, normal and shear stresses in the solder layer under the die are found to be larger in magnitude for both AlN`s than for the BeO. Qualitatively, the lower {open_quotes}volume specific heat{close_quotes} ({rho}{circ}C{sub p}) of AlN might be expected to provide a faster heating ramp of the transistor than would be estimated from its thermal conductivity alone. Modeled temperature transients for power-on transients are virtually the same -- within 1{degrees} C -- for the BeO and the higher-{kappa} AlN.

OSTI ID:
535625
Report Number(s):
CONF-941199-; TRN: 97:003395-0012
Resource Relation:
Conference: Joint American Ceramic Society (ACS) Electronics Division/ISHM Fall meeting, Boston, MA (United States), 15-17 Nov 1994; Other Information: PBD: 1996; Related Information: Is Part Of Ceramic transactions: Hybrid microelectronic materials. Volume 68; Nair, K.M.; Shukla, V.N. [eds.]; PB: 301 p.
Country of Publication:
United States
Language:
English