Transient Thermal Simulation for Socket Design Evaluation & Characterization

Abstract

With the lead time to market for semiconductor products getting shorter, there is an ever increasing pressure on assembly and testing to reduce their yield time too. Sockets are the interface between the device under test (DUT) and the tester. Also, with the packaging trend towards short form factor and pitch reduction, it is a challenge to design the socket with reduced lead-time and with lesser revisions. Software simulation thus becomes inevitable not only for designing but also socket improvement. An existing socket with non-uniform temperature distribution was evaluated utilising a transient computational fluid dynamics (CFD) and thermal analysis to determine the non-uniform temperature distribution within socket as a function of air flow velocity with respect to time. Air inlet boundary conditions such as flow velocity and temperature and the opening with atmospheric pressure at the outlet were assigned to the cuboid assembly and analyses run for transient boundary conditions. Transient temperature distribution profile at various time instances were visualised to understand the temperature increase in the socket regions. CFD and thermal simulation on the evaluation of air flow helped to understand the air flow variations with the test socket assembly and the resultant rise in temperature at various pins that probe the temperature. Thus, simulation helped to optimise socket design for effective air flow and desired temperature can be achieved by understanding the flow behaviour in the test chamber.