Eliminating gold wire bond failure using combined Ishikawa and Taguchi methodology for robust IC packaging

In traditional semiconductor integrated circuit (IC) packaging, the wire bonding process is critical for establishing reliable electrical connections. A major challenge in this process is gold ball detachment, primarily caused by inadequate intermetallic compound (IMC) formation at the gold ball–aluminum pad interface. This issue becomes more severe when aluminum pads contain large probe marks from wafer testing, reducing the effective bonding area and weakening joint strength. This study proposes a systematic optimization of wire-bonding parameters to enhance bonding strength and minimize gold ball detachment. The Taguchi method with an L9 orthogonal array was applied to evaluate 3 key factors: Scrub Cycle, Ultrasonic Generator (USG) Power, and Bond Force. Analysis of variance (ANOVA) and signal-to-noise ratio (S/N) analysis were conducted to determine the optimal parameter combination. The results show that a Scrub Cycle of 2, USG Power of 53 mA, and Bond Force of 13 g significantly improve IMC Coverage and Ball Shear Strength. After implementation in mass production, the gold ball detachment rate decreased from 1112 parts per million to 16 parts per million. These findings confirm the effectiveness of the Taguchi method in improving yield, reliability, and manufacturing performance.