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Heavy copper (Cu) wire bonding is dominant in high power Integrated Circuit (IC) devices at various packages known for good mechanical characteristics, better electrical resistivity, and excellent cost. Larger wire diameter has more opportunity to replace Gold (Au) and Aluminum (Al) wire for Quad Flat No-lead (QFN) package. This study used 4 mils diameter Cu wire aimed to develop heavy wire ball bonding process on high IC power technology in QFN package. The experimental trials challenge the current machine capability on heavy ball bonder to meet bonding criteria. Capillary tool dimensions and leadframe clamping design are critical for maximizing the parameters limit of the machine for successful and stable bonding. Important wire bonding steps such Free Air Ball (FAB), Ball Bond, Looping formation and Stitch bond were characterized and examined for the bondability test through Design of Experiment (DOE) and Robust Validation (RV) test. Accelerated High Temperature Storage (HTS) was conducted to verify the bonding integrity with thermal ageing by Destructive Physical Analysis (DPA) through ball shear and wire pull test. In this paper, the wire ball bonding development on 4 mils copper wire showed remarkable results using current auto ball bonder but it requires modification and system upgrade for manufacturability.