shows the shear force and the contact area between
the gold bumps and the aluminum pads as a function
of bonding power. The shear force first increases sharply
with increasing bonding power. Beyond a certain value,
any further increase in bonding power only leads to a gradual
increase in shear force. The trend of contact area is similar
to that of shear force, while their rates of increase are
different in the lower range of bonding power.