engineering lots

**Engineering Lots** are **small quantities of wafers processed through the fab for development, process characterization, or design validation purposes** — not intended for production, engineering lots are used to evaluate new processes, test design changes, debug yield issues, and qualify process modifications. **Engineering Lot Types** - **Process Development**: Test new recipes, materials, or equipment — evaluate process capability before production. - **Design Validation**: First silicon — build a new design to verify functionality. - **DOE (Design of Experiments)**: Systematic variation of process parameters — split lots with different conditions. - **Yield Learning**: Short loops focusing on specific process modules — accelerate learning without full-flow wafers. **Why It Matters** - **Risk Reduction**: Engineering lots validate changes before they affect production — catch problems early. - **Speed**: Small lots (1-5 wafers) move through the fab faster than full production lots (25 wafers). - **Cost**: Engineering lots consume fab capacity — balancing development needs with production throughput is critical. **Engineering Lots** are **the fab's experiments** — small-quantity wafer runs for development, validation, and learning without risking production throughput.