hast test

**HAST** (Highly Accelerated Stress Test) is a **reliability test that combines elevated temperature and humidity under pressure** — to accelerate corrosion and moisture-related failure mechanisms in semiconductor packages at a much faster rate than standard Temperature-Humidity-Bias (THB) testing. **What Is HAST?** - **Conditions**: 130°C, 85% RH (Relative Humidity), under bias voltage, in a pressurized chamber (2 atm). - **Duration**: 96-264 hours (vs. 1000 hours for standard 85/85 THB). - **Acceleration Factor**: ~10x faster than unchamber-corrected 85°C/85% RH test. - **Standard**: JEDEC JESD22-A110. **Why It Matters** - **Corrosion**: Moisture + voltage causes electrochemical migration (metal dendrites shorting adjacent traces). - **Delamination**: Moisture ingress at package interfaces weakens adhesion. - **Time Savings**: Qualifies packages in weeks instead of months compared to THB. **HAST** is **a pressure cooker for chips** — using extreme humidity and heat to expose moisture vulnerability in semiconductor packaging.