A stud bump structure for electrical interconnection between a pair of
members includes a base portion, and a stem portion. The base portion is
affixed to a pad or trace in one of the pair of members to be
interconnected (such as an integrated circuit chip), and the stem end is
configured to contact a metal pad on the other member (such as a printed
circuit board) to complete the interconnect. According to the invention,
the stem end is truncated to form a transverse plane, and the stem is
more compliant than the base. Also, a method for forming a stud bump on a
contact surface, includes forming a bump base portion on the surface,
drawing out a generally conical tail from a top of the base, and
truncating the tail to form a stem portion having a planar transverse top
surface and having a length from the top of the base portion to the top
surface. In some embodiments the tail portion, at least, of the stud bump
is formed using a wire bonding tool. Also, a method for forming an
interconnect between a first member and a second member of an electronic
package includes providing one of the members with the stud bumps of the
invention and then bringing the corresponding bumps and pads together in
a bonding process, the compliance of the stems portions of the bumps
accommodating the variance from coplanarity of the pad surfaces.