THERMAL DISSIPATION CHARACTERISTICS OF A TAPE AUTOMATED BONDING ELECTRONIC PACKAGE

Thermal measurements play a very important role in the successful desi gn and thermal management of electronic packages. Accurate measurement s of temperature distribution under different conditions are necessary to characterize the thermal resistance of electronic packages from th e chip junction to the cooling sink. This paper deals with the effects of power dissipation, air velocity and ambient temperature on the the rmal performance of a tape automated bonding (TAB) package. In this st udy, the characteristics of junction temperature (T-J), junction to am bient thermal resistance (theta(J-A)), junction to case thermal resist ance (theta(J-C)), and case to ambient thermal resistance (theta(C-A)) are investigated in detail. The package was placed in a custom-design ed low speed wind tunnel which allows the air velocity to be varied be tween 0.5 m/s and 5 m/s. Package surface temperatures were measured us ing infrared thermography, while chip junction temperatures were indir ectly obtained using the Electrical Test Method (ETM) in accordance to Military Standard 883. The experimental results show that for the TAB package, air velocity significantly affects theta(C-A) and theta(J-A) but has negligible effect on theta(J-C). In contrast, theta(J-C) was found to be dependent on power dissipation. In addition, the ambient t emperature was found to have a strong effect on the thermal performanc e of the TAB :package. For the tested TAB package, it was noted that t he inner lead temperatures are higher than that of the chip epoxy surf ace.