die shear test

**Die Shear Test** is a **destructive mechanical test that measures the adhesion strength of the die to the package substrate** — by applying a lateral (shearing) force to the side of the die until it separates from the die attach material. **What Is the Die Shear Test?** - **Standard**: MIL-STD-883 Method 2019, JEDEC JESD22-B116. - **Procedure**: A flat tool pushes against the side of the die. Force is measured until failure. - **Failure Modes**: - **Adhesive Failure**: Clean separation at the interface (weak bond). - **Cohesive Failure**: Die attach material itself fractures (acceptable — material is strong enough). - **Die Fracture**: Die itself breaks (too much force, over-specification). **Why It Matters** - **Die Attach Quality**: Validates die attach process (epoxy dispense, solder reflow, or eutectic bonding). - **Thermal Performance**: Poor die attach (voids) degrades thermal conductivity. - **Reliability**: Weak die attach can lead to delamination and field failures under thermal stress. **Die Shear Test** is **the foundation strength test** — ensuring the die is firmly anchored to its substrate for the lifetime of the product.