PROJECT TITLE :

Effect of Capillary Trace on Dynamic Loop Profile Evolution in Thermosonic Wire Bonding

ABSTRACT:

Thermosonic wire bonding remains the foremost commonly used interconnection technology in microelectronic packaging, and looping is a vital side in modern wire bonders. To spot the loop formation mechanism, the impact of capillary trace on the quality wire looping process was studied. Dynamic looping processes with totally different capillary trace parameters and reverse motions of four, eight, and 16 mil were recorded by a high-speed camera. The capillary trace and wire profile evolution were obtained from the looping videos using a digital image processing program, and the link between capillary trace and loop profiles was analyzed. A finite-component model was established to study the strain distribution on wire during looping. Experimental and simulation results show that the wire profile of the standard loop is mainly plagued by capillary position and is not sensitive to capillary velocity. The upward capillary trace mainly affects the loop configuration, as well as the quantity, position, and deformation of kinks and therefore the loop length. The downward capillary trace affects the strain states, loop height, kink deformation, and loop profiles. A kink is that the wire with the most important local curvature, and it is a plastically deformed wire segment with very little elastic core. The kink has 2 functions: 1) shaping the loop and a couple of) isolating the pulling force on the first bond and neck caused by capillary movement. This paper will be of nice facilitate in loop profile optimization within the business and in educational analysis of loop dynamics.