IMPORTANT ELEMENTS IN FINE PITCH BONDING APPLICATIONS
BOND PAD PITCH:
The distance between the centers of the bond
BOND PAD SIZE:
May be square, rectangular, or round. The most
important dimension is the size along the pitch, as shown above.
The most important aspect of wire loop height
is the loop height directly adjacent to the capillary, if the capillary is designed to
clear a maximum loop height that occurs away from the capillary, the "T"
dimension will be less than required, resulting in a less than ideal second bond.
The designed clearance between the capillary
angle bottleneck and the adjacent wire tolerances, capillary manufacturing tolerances,
loop control, and desired quality standards can all influence the designed clearance. The
following tables were computed using 0.0005in./13µ wire to angle bottleneck clearance
(critical clearance shown above).