Method for controlling the formation of intermetallic compounds in solder joints

摘要

The present invention relates to a method for controlling the formation of the intermetallic compounds in solder joints, The types of the intermetallic compounds between the SnAgCu solders and the Ni-bearing substrate can be controlled by adjusting the copper concentration in the SnAgCu solders. If the SnAgCu solder has a copper concentration higher than or equivalent to 0.6 wt. %, the soldering intermetallic compound includes a continuous (Cu1-xNix)6Sn5 layer. If the copper concentration of the SnAgCu solders is lower than or equivalent to 0.4 wt. %, the soldering intermetallic compound includes a continuous (Ni1-yCuy)3Sn4 layer and a non-continuous (Cu1-xNix)6Sn5 layer. If the copper concentration of the SnAgCu solders is between 0.4 wt. % to 0.6 wt. %, the soldering intermetallic compound includes the continuous (Cu1-xNix)6Sn5.