J. C. Patents
Method for controlling the formation of intermetallic compounds in solder joints
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&#8722;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&#8722;yCuy)3Sn4 layer and a non-continuous (Cu1&#8722;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&#8722;xNix)6Sn5.
National Central University
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Y10T Y10T Y10T B23K H05K H01L H05K
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Cheng-En Cheng-Heng
Ho Kao