Mechanical and electrical characterization of a dendrite connector

A dendrite connector has a taller asperity field than conventional connectors. The surface texture of dendrites on 322 pads has been measured using a WYKO RST Plus/sup TM/ 3D optical profilometer. The measurements were used to build statistical distributions of the dendrite height and bearing area functions for the force and resistance models. Mechanical and electrical characteristics of a dendrite pad mating with a smooth surface have been studied using two separate experimental techniques. The first set of experiments was done using a computer controlled micro-mechanical tester. A dendrite pad was pushed by a steel rod against a smooth gold plated steel block. The rod was moved in 1 /spl mu/m steps and the resulting force and resistance at 13 current levels were recorded. In the second set of experiments, a dendrite pad was pushed against a glass microscope slide and the contacting dendrites were observed by placing the entire fixture on a Metallograph microscope. The force was applied using a differential screw and the resulting load was measured using a small load cell attached to the screw. Thus the loading process was directly observed, and images were digitized and processed to determine the contact spots and contact area. Following the mechanical loading, the dendrite samples were again scanned using the WYKO profilometer to determine the permanent deformation of the dendrites. With measured statistical data for the dendrite pads, a Greenwood and Williamson type model was used to predict the contact force and resistance. The results from the model are compared with the experimental results and observations.