Ball bond lifting, or simply ball lifting, is the detachment of a ball bond from the bond pad.   It can be due to a variety of factors.  Poor wirebonder set-up and bond pad surface contamination are primary causes of ball lifting.  Poor set-up includes improper parameter settings, unstable workpiece holders, and worn-out tools.  These result in poor initial welding and inadequate intermetallic  formation between the bond pad and the ball.

Ball lifting can also be due to contaminants on the bond pad, which act as barriers between the ball and the bond pad.  Common contaminants that inhibit good bonding include unetched glass, unremoved photoresist, and Si saw dust.  Resin bleed-out from the die attach material can also impede good bonding and result in ball lifting. Halides such as Cl on the bond pad can trigger corrosion, which is again another source of ball lifting. Silicon nodules on the surface of bond pads with no barrier metallization underneath can also result in poor ball bonding.

Lifted balls may also result from excessive interdiffusion between the bond pad and ball bond metals. Kirkendall voiding, which is the formation of voids underneath the ball bond due to excessive diffusion of Al from the bond pad to the Au ball bond to form purple plague, is an example of this mechanism.  The reflow of thermoplastic die attach material at the bonding temperature also results in ball lifting, because it allows movement of the die during the thermosonic bonding itself. 

Cratering, which is considered to be a different failure mechanism, can also manifest as a lifted ball, with the Si underneath the bond pad coming off with the bond.  Similarly, bond pad peel-off from the barrier metal can result in ball lifting. Studies have likewise shown that excessive probing damage or deep probe marks on the bond pad can lead to ball lifting.