ACHIEVING ACCURATE THERMAL CHARACTERIZATION USING A CFD CODE - A CASE-STUDY OF PLASTIC PACKAGES

Achieving component-level thermal characterization using computational fluid dynamics (CFD) is assessed using a case study approach, A comme rcial CFD code (FLOTHERM(R)(1)) is used to simulate the thermal perfor mance of three plastic-based microelectronic packages (68-lead and 84- lead plastic leaded chip carriers or PLCC's, and a 164-lead plastic qu ad flat pack or PQFP) under forced air cooling conditions, Predictions of junction-to-ambient thermal resistance (theta(j alpha)) are compar ed to experimental measurements, One aspect of the work is to use resu lts from a single situation (84-PLCC and an approach air velocity of 1 .52 m/s) to develop a set of ''modeelng guidelines.'' These modeling g uidelines are then applied to the other components (68-PLCC and 164-PQ FP) and flow conditions (0.76-3.05 m/s) to test their validity, Guidel ine parameters include near component flow field nodalization, geometr ic detail in representing conduction paths and code user options such as turbulent flow models, The average deviation of predicted versus me asured values of theta(j alpha) was 7.5% using the derived guidelines, An additional component design sensitivity investigated was the effec t of the introduction of a heat spreading ''heat post'' in the high te mperature regions of the 164-PQFP.