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.