Template Assisted Manufacturing of Low-Temperature Copper-Based Nano solder.

摘要

As a response to new legislation and calls to lead-free technologies, a method is proposed to manufacture nano-copper by means of electroless copper plating on nanofibers templates. Polyacrylonitrile (PAN) nanofibers were prepared by electrospinning solutions of said polymer and dimethylformamide. The fibers were cleaned, etched and activated using chemical solutions for subsequent copper deposition. The coating solution was found to properly reduce copper when maintained at a pH of 11-12.;SEM and optical characterization revealed copper deposited on the fibers making a 250 nm layer around the 500 nm nanofibers. A melting point range for the manufactured nano-copper was determined by heating samples at different temperatures in a high temperature oven. Results showed how first the copper on the nanofiber melts at around 600°C and complete melting of the copper occurs at 800°C. Once the melting temperature range was determined, samples were prepared for mechanical testing. Copper strips were soldered together with the nano-copper in the oven and tested on a tensile strength tester. Specimens failed at loads of 10-60 N, showing to have appropriate mechanical properties for solder applications.