Parametric studies of the thermal performance of back-to-back tape ball grid array (TBGA) packages

This paper deals with parametric studies to evaluate the thermal performance of Tape Ball Grid Array (TBGA) packages mounted in back-to-back configurations onto organic printed circuit boards. A cover plate is attached to the back side of the chips to enhance heat transfer from the module. The assembled organic carrier is placed in a vertical channel. A conjugate heat transfer model is used which accounts for conduction in the packages and the card and convection in the surrounding air. The effect of location of the modules on a card with 0, 1 and 2 power planes is evaluated for thermal performance. Four different configurations of the TBGA modules on the card are investigated. Heat dissipation is studied for forced convection (2, 1, and 0.5m/s). The best performance resulted when the modules were placed at an offset. The bottom of the card is very useful for heat dissipation and blocking that heat transfer path by placing another TBGA on the back side is counter productive.