Study of the Wrinkle Formation in the Heel Zone of Heavy Wire Bonds

This study observes a wrinkling measurement method for non-destructive optical measurements of deformed bondheels. The wire bonds are manufactured by an ultrasonic wedge/wedge bonding process. The wire loops are formed with different bending radii, set by the machine parameters reverse factor and reverse height. The measurement method is based on a modified surface roughness analysis and was transferred from planar surfaces to the bent heel area of Al heavy wire bonds on nickel-plated aluminum. Using this, it is possible to deduce information about damaging and reinforcement processes in the heel.