Abstract
This paper presents the experimental results concerning the effects of packaging density to the thermal performance of a PBGA package model mounted on a printed circuit board in a thin compact casing. The casing exit was linked with an exhaust duct, which has an orifice plate for flow measurement in the middle, and an exhaust fan at the end. The thermal resistance values of the package were plotted against the ratio of the obstacle volume to the casing volume and the ratio of obstacle sectional area to the inlet. The results demonstrate that there exist different temperature rise distributions even when both the ratio of the obstacle sectional area to the inlet area and the ratio of the obstacle volume to the casing volume are the same.
