The use of the Pb-contained solder in electronics has been a growing environmental concern. Legislation dealing with hazardous materials such as Pb is being drafted in Europe. Meanwhile, Japan and Korea, especially, have concentrated on producing Pb-free products. Pb-free solder bump for the flip chip package is also needed now, and there will be more need for a low cost bumping process. Two kinds of Pb-free solder bumps, such as SnAg and SnAgCu, by using stencil printing were compared with the eutectic and high Pb solder bump on electroless Ni under bump metallurgies. The bump shear values were measured after temperature cycling, pressure cooker test, and high temperature storage. Even though the deviation of the shear value of the Pb-free solder bump in initial state was high, the average value was higher than that of Pb-contained solder bump. Among Pb-free solder bumps and Pb-contained solder bumps, the SnAg bump has the highest shear value, but the value decreases with time more rapidly than those of other types of bumps. This rapid decrease may be due to the thicker intermetallic compound of the SnAg bump.
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