Heat conduction in printed circuit boards: a mesoscale modeling approach

An analytical model is developed to estimate the heat transfer performance of printed circuit board (PCBs). The PCB under study is the substrate for a ball-grid-array (BGA) package. Under the BGA, the PCB has a belt of densely populated through-vias that penetrate the laminate of horizontal copper and resin; outside the BGA-covered area the board is a copper/resin laminate and its surfaces are exposed to cooling air. Calculations are performed on a sample board having the dimensions 11 x 11 [cm.sup.2] (footprint) x 1.26 mm (thickness). The model of the board has two internal layers of continuous copper (0.03 mm thick) and through-vias under a 4.4 x 4.4 [cm.sup.2] BGA package. The impacts of board design parameters on the temperature and the heat flow are presented; the parameters are the width of the insulation gap around the via, the area of copper coverage at the via bottom, and the population of vias. [DOI: 10.1115l/1.2993126] Keywords: printed circuit board, heat conduction, analytical modeling, through-vias, copper/rein laminate