An influence of substrate thickness on electrical conductivity of dip-soldered copper joints

Abstract

Tin (Sn) metal is used as a major ingredient in various levels of solders (both lead bearing and lead free) to join electronic components whereas, copper is the most common substrate material to be in direct contact with electronic solders. In this regard, study on the reaction between tin and copper (Cu) is of great practical interest. Copper substrates of two thicknesses (0.3 and 3 mm) were immersed in liquid tin (maintained at 350°C) for the duration of 3mins. An immersion and redrawn speed maintained was 2.5mm/s. An interfacial reaction between substrate metals of different thickness and liquid tin vice versa was investigated. Effect of substrate thickness on electrical resistivity and electrical conductivity was accessed. It was observed that as the thickness of Cu substrate increases both electrical conductivity decreases.