In Situ Study the Grooving Effect Induced by Ag Particles on Rapid Growth of Cu₆Sn₅ Grain at Sn-xAg/Cu Soldering Interface during the Heat Preservation Stage

Abstract

Synchrotron radiation X-ray imaging technique was applied for in situ observation of Cu6Sn5 intermetallic compounds (IMC) growth in Sn/Cu and Sn-3.5Ag/Cu joints under isothermal temperature conditions of 250/300/350 °C and time duration of 1.5 h. The IMC in Sn-Ag solder was characterized by the formation of grooves during the interfacial reaction, and this can be attributed to the Ag content. Kinetically, the growth rate constants for the height of Cu6Sn5 were observed to increase with temperatures and the presence of Ag in solder. As compared to pure Sn solders, the Sn-3.5Ag solders were observed with interfacial IMC of greater height, smaller base width, and lowered aspect ratio.

Keywords

• reflow soldering
• synchrotron radiation
• intermetallic compounds
• grooves
• growth kinetics