lifted bond

**Lifted bond** is the **wire-bond failure mode where the bonded interface separates from the pad or lead surface after bonding or during reliability stress** - it indicates insufficient metallurgical and mechanical attachment strength. **What Is Lifted bond?** - **Definition**: Interconnect defect in which a first or second bond detaches from its intended landing surface. - **Common Locations**: Can occur at die-pad ball bond, stitch bond on leadframe, or both. - **Failure Signatures**: Observed as non-stick, partial lift, intermittent continuity, or open circuit. - **Root Drivers**: Includes poor surface cleanliness, weak intermetallic formation, and off-window bond parameters. **Why Lifted bond Matters** - **Electrical Risk**: Lifted bonds create intermittent or permanent opens that fail functional test. - **Reliability Impact**: Bonds near failure may pass initial test but fail in thermal cycling. - **Yield Loss**: Lift-related defects are high-impact contributors to assembly fallout. - **Process Health Signal**: Rising lift rates often indicate tool wear, contamination, or recipe drift. - **Customer Quality**: Lifted bonds can cause field returns and warranty exposure. **How It Is Used in Practice** - **Failure Analysis**: Use pull and shear testing with microscopy to classify lift mechanism. - **Parameter Optimization**: Retune force, ultrasonic power, and temperature for stable bond formation. - **Surface Control**: Strengthen pad and lead cleaning, oxidation management, and metallurgy qualification. Lifted bond is **a critical wire-bond defect that requires rapid corrective action** - controlling lift mechanisms is essential for assembly yield and long-term reliability.