ball shear test

**Ball Shear Test** is a **destructive mechanical test that evaluates the bond strength of a ball bond (first bond)** — by applying a lateral force to the bonded ball with a chisel-shaped tool until the ball shears off the bond pad. **What Is the Ball Shear Test?** - **Standard**: JEDEC JESD22-B116. - **Procedure**: A shear tool is positioned next to the ball bond at a height of ~25% of ball diameter. Lateral force is applied until failure. - **Failure Modes**: - **Ball Lift**: Ball separates cleanly from pad (intermetallic failure — bad). - **Ball Shear**: Ball deforms and shears through (bulk material failure — good). - **Cratering**: Pad/oxide/silicon fractures beneath the bond. **Why It Matters** - **Intermetallic Growth**: Au-Al or Cu-Al intermetallic quality directly affects shear strength. - **Process Optimization**: Monitors bonding parameters (force, ultrasonic energy, temperature, time). - **Cu Wire Adoption**: Critical test for validating copper wire bonding on aluminum pads. **Ball Shear Test** is **the quality check for the first bond** — verifying the metallurgical integrity of the connection between wire and chip.