A delamination acts like a high thermal resistance that reduces the ability of an IC package to act like a heat sink, so a delaminated die can overheat. A large or growing delamination worsens this effect and the die may eventually overheat to the point that it fails. When a delamination extends across the entire die-attach surface, the die may remain held in place only by the fragile lead wires, which will break when stressed. A second type of opening, called a void, appears as a large gap in the die-attach material. Also, the lack of sufficient die-attach material applied during manufacturing can create voids.
Voids tend to act as the nucleus for horizontal cracks.
The stresses that result from different coefficients of thermal expansion increase at distances further from the center of die. Thus, the highest stresses occur at the corner of the die, and defects near the corners of a die are more likely to result in device failure. Conversely, a small defect near the center of the die-attach material may never expand into a lethal defect. By carefully examining any defects, these manufacturers can determine their causes and can act to prevent them in the future. An IC manufacturer might correct this by cleaning surfaces more thoroughly to remove contamination.