Thermal/mechanical analysis of novel Ceramic-TSOP using nonlinear finite element method

This research proposed a novel ceramic thin-small-outline package (Ceramic-TSOP or C-TSOP) to meet the high thermal performance and long-term reliability considerations for today's low-pin-count, highperformance electronic devices. To improve the molding compound and to simplify the fabrication process, molding compound is replaced by ceramic-like stiffener which is adhered to the leadframe by a tape or adhesive as shown in Figs. 1(a) and 1(b). The ceramic-like stiffener will overcome the low thermal conductivity problem of molding compound in a conventional LOC-TSOP (Fig. 2) and increase the efficiency of thermal dissipation in the LOC-TSOP. In this research, three-dimensional (3D) nonlinear finite element models of both the conventional and novel LOC-TSOP have been established. Various heat generation levels are applied to the 3D nonlinear models under natural convection conditions to evaluate heat dissipation capability and thermal resistance of the packages. The material properties and solder joint reliability of the packages are also investigated. In order to compare the solder joint reliability of the novel LOC-TSOP to the conventional LOC-TSOP, a nonlinear finite element method is used to analyze the physical behaviors of packages under thermal loading. The results are compared with experiments reported in the literature in order to demonstrate the accuracy of the finite element models. From the results, it can be concluded that the novel Ceramic-TSOP package implies excellent thermal performance and appropriate solder joint reliability.