mean time between cleaning

**Mean time between cleaning** is the **average run duration between required cleaning interventions to keep equipment within contamination and process-control limits** - it reflects chamber fouling behavior and directly affects uptime and yield stability. **What Is Mean time between cleaning?** - **Definition**: Operating time or wafer count between planned chamber or subsystem cleaning events. - **Primary Drivers**: Process chemistry, deposition byproducts, polymer buildup, and particulate generation. - **Metric Forms**: RF hours, wafer passes, or elapsed process time depending on tool type. - **Control Objective**: Maximize cleaning interval without crossing quality-risk thresholds. **Why Mean time between cleaning Matters** - **Throughput Impact**: Short cleaning intervals reduce available production time. - **Yield Protection**: Excessive extension of intervals can cause particles, drift, and defect excursions. - **Cost Optimization**: Cleaning frequency drives labor, consumables, and downtime burden. - **Process Stability**: Consistent MTBC supports predictable chamber behavior across lots. - **Improvement Opportunity**: Chemistry and hardware tuning can materially increase interval length. **How It Is Used in Practice** - **Interval Baseline**: Establish MTBC by process family using yield and particle performance limits. - **Condition Monitoring**: Use sensor and metrology trends to adjust cleaning timing before excursion. - **Optimization Loop**: Test in-situ clean recipes or hardware changes and track MTBC shift. Mean time between cleaning is **a key availability and contamination-control metric** - balanced MTBC settings protect both output capacity and process quality.