Wirebond Process Improvement through Silicon Die Polyimide Removal | Journal of Engineering Research
This study aims to develop polyimide etching process on the silicon die after decapsulation to resolve the wire shear issue during ball shear data gatherings. The shear strength of the ball is affected by the presence of polyimide insulator during ball shearing process, due to the polyimide layer of the silicon die being coplanar with the ball height of the wire. Experimentation and statistical analysis were done on units with and without polyimide coating, with Sodium Hydroxide (NaOH) used to remove the excess polyimide. Results revealed that silicon dice without polyimide coating resulted to better reading in terms of ball shear.
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