Effect of electroplating parameters on electroplated Cu film and microvoid formation of solder joints

The influences of electroplating parameters on electroplated Cu (EPC) film and void formation at the Sn3.0Ag0.5Cu (SAC305)/Cu interface were investigated. It is found that the size of Cu particles increased with the increase of current density or deposit thickness. The surface roughness of Cu films also increased with increasing current density. And the surface roughness of EPC films demonstrated decrement at first and then increment with the increase of deposit thickness. It is observed that the electrodeposition with higher current density or thicker Cu film tended to inhibit the growth of Cu(111) and favor the growth of Cu(220). After reflowing and thermal aging, the voiding level increased greatly as the current density and deposit thickness increased, and that total microvoid area increased gradually with increasing aging time for all electroplating conditions. Additionally, the variation in the current density and deposit thickness did not influence the intermetallic compound growth rate.