assembly yield

**Assembly yield** is the **percentage of die surviving the packaging process** — measuring quality of die attach, wire bonding, molding, and other assembly steps, typically 98-99.5%, with failures indicating handling damage, process issues, or equipment problems. **What Is Assembly Yield?** - **Definition**: (Good packages / Die input) × 100%. - **Typical**: 98-99.5% for mature processes. - **Measurement**: From die input to packaged device output. - **Impact**: Determines packaging cost per good unit. **Why Assembly Yield Matters** - **Cost**: Low yield wastes expensive die and packaging materials. - **Throughput**: Yield loss reduces effective capacity. - **Quality**: Assembly defects can cause field failures. - **Process Control**: Yield trends indicate equipment health. **Failure Modes** - **Die Attach**: Voids, delamination, cracking. - **Wire Bonding**: Broken wires, poor bonds, shorts. - **Molding**: Voids, wire sweep, package cracks. - **Handling**: Die breakage, contamination, ESD. **Improvement**: Focus on equipment maintenance, process optimization, and handling procedures to maximize assembly yield. Assembly yield is **the packaging efficiency metric** — high yield means reliable, cost-effective packaging that preserves the value of expensive die.