Process Design of Fine Pitch Ball Bonding by Volume Conservation Modelling

Rationally Designing the Trace of Wire Bonder Head for Large-Span-Ratio Wire Bonding in 3D Stacked Packaging

“…The development trend of wire bonding has the following three characteristics: the diameter of wire is continually shrinking towards sub-10 µm when trying to reduce the cost and achieve smaller pitch [15]; an effective pitch of less than 50 µm between bonding pads is the tireless pursuit of packaging industry [16]; the span between the two bonds continuously increases but the wire loop profiles is severely lowered so as to interconnect as many chips as possible in a confined space that is thinner than a standard wafer, the ratio of the distance between the 1st & 2nd bonds and the loop height expected to be larger than 5 [17,18]. In a wire loop, the reasonable distribution of kinks on it not only defines the geometrical shape of the wire loop but also effectively prevents wire sagging and short-circuit defects [19].…”