Modified M-Loop Wire Formation: An Innovative Solution in Wire Bond Process to Relieve Stress on Ball Neck Causing Broken Wire

Abstract

The extent of this paper covers thin package with thicker die. In a thin package design with thick frame, low loop height requirement is expected. This condition is set to avoid exposed wire after Mold process and damage wire after Laser Mark process for pin identification. In Wire Bond process the assessment of low loop formation is critical. Low loop formation is susceptible to stress at ball neck and is known to be the foremost cause of broken wire issue. Normal loop profiles on thick die insist of having stress on ball neck and broken wire issue due to limited clearance to form the wire loop. The modified M-Ioop wire formation is the innovative solution for thicker die to meet the package loop height requirement and criteria with no sign of stress at ball neck and zero reject of broken wire.