Abstract
This research describes a novel ceramic thin-small-outline package (C-TSOP) to meet the thermal performance and long-term reliability considerations of today's low-pin-counts and high-performance electronic devices, especially for memory devices. To improve the disadvantages of molding compound and simplify fabrication process, molding compound is replaced by ceramic-like stiffener which is adhered to the leadframe by tape or adhesive as shown in Figure (1a) and Figure (1b). The ceramic-like stiffener would overcome the low thermal conductivity problem of molding compound in a conventional LOC-TSOP (Figure 2) and increase the efficiency of thermal dissipation of the LOC-TSOP. In this research, three-dimension (3D) nonlinear finite element models of both the conventional and novel LOC-TSOP have been established. Various heat generation are applied to the 3D nonlinear models under a natural convection condition for evaluating heat dissipation capability and thermal resistance of the packages. Moreover, the materials properties and solder joints reliability of the packages are also investigated. In order to compare the solder joints 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 a thermal loading condition. The thermal fatigue life of the solder joints has been estimated in term of the equivalent plastic strain. The results and extensively compared to the experiments in the literatures in order to demonstrate the accuracy of the finite element models. From the results, it can be conducted that the novel C-TSOP package implies excellent thermal performance and appropriate solder joint reliability.