quality rate

**Quality rate** is the **OEE component that measures the proportion of good output versus total output started during production** - it captures value-creating yield after accounting for scrap, rework, and startup losses. **What Is Quality rate?** - **Definition**: Ratio of conforming units to total units processed in the measured interval. - **Manufacturing Context**: In semiconductor operations, quality rate is tightly linked to electrical yield and defect density. - **Loss Components**: Includes process defects, handling damage, and nonconforming startup wafers. - **OEE Position**: Multiplies with availability and performance, so quality losses directly reduce overall equipment effectiveness. **Why Quality rate Matters** - **Revenue Protection**: Only good wafers create shippable value, so quality rate has direct financial impact. - **Hidden Cost Signal**: Scrap consumes full process cost before value is lost at final test or metrology gates. - **Process Stability Indicator**: Degrading quality rate often reveals drift in equipment, recipe, or materials. - **Improvement Prioritization**: Quality losses help identify where defect prevention gives highest return. - **Customer Confidence**: Stable quality rate supports predictable output and delivery commitments. **How It Is Used in Practice** - **Metric Governance**: Standardize defect and rework classification so quality rate is comparable across tools. - **Loss Segmentation**: Separate chronic defects from startup and maintenance-related quality losses. - **Action Tracking**: Tie quality-rate changes to corrective actions in process control and maintenance programs. Quality rate is **the value-realization factor of equipment performance** - high throughput only matters when the resulting wafers consistently meet quality requirements.