Semiconductor final test fixture design with microstructure alloy contacts using Finite Element Analysis

In this paper, a novel electrical contact mechanism that serves as a low insertion-force test socket is investigated by finite element analysis. The proposed electrical contact mechanism is made up of three different materials such as polymer, metallic alloy and liquid metal. Due to the uneven stress distribution of the conventional pogo pin systems, large puncture marks occur on the integrated circuit contacts. The proposed design enhances the overall stress distribution performance of the electrical contact with integrated circuit as found from the analysis. Parameters such as the number of microstructure contacts and the pitch size among them give influential impact on the overall stress distribution performance. Generally, the more the microstructure contact, the more the stress distribution gets evenness. However, the stress distribution becomes saturated when the number of microstructure contacts reaches 16 for a total area of 0.25 mm × 0.25 mm. The pitch size of 0.07 mm gives the best performance for the given total contact area. Any pitch above will set the microstructure contacts to the edges of the contact area, which decreases the stress distribution performance. A factor of safety analysis is performed for the proposed design and a value of 4.9 is achieved, which is almost 5 times greater than the minimum requirement of 1.0.