Fundamentals based approach to predict socket stack performance

The field performance of a separable socket/connector is governed by its ability to maintain the target contact resistance throughout its life. Contact resistance stability and protection against field degradation mechanisms is achieved by maintaining a critical normal force on the contact. With growing socket contact pin counts and package complexities there are challenges with achieving and maintaining this critical contact normal force across the array of contacts in the socket. In this effort, the authors characterized the key mechanical and resistance relationship (Force-Deflection-Resistance)through single contact resistance measurements. An analytical model of a socket stack was developed to better capture the contact normal force distribution across the contact array. The contact forces extracted from the analytical model were then converted to contact resistances through the Force-Deflection-Resistance relationship obtained from single contact resistance measurements. Force-Resistance variation from contact to contact was comprehended through a Bootstrapping technique. This fundamental based approach of using finite element, single contact data and statistics was then validated against fully enabled socket measurements using electrically daisy chained test vehicles.