Tail breaking forces (TBFs) are measured for various process conditions to understand phenomena such as short tail formation. TBFs obtained with several Cu wires are compared to find the most suitable Cu wire type that improves consistent tail formation. In situ online TBF measurement method is developed. The highest TBF obtained is 61.59 + 9.10mN. The highest Cpk value obtained is 2.97 + 0.33 when lower specification limit of 10 mN is assumed.