tool capacity planning

**Tool capacity planning** is the **process of determining required equipment count and utilization targets to meet forecast wafer demand with reliability headroom** - it aligns production goals with realistic tool performance and downtime assumptions. **What Is Tool capacity planning?** - **Definition**: Capacity modeling that translates demand forecasts into tool-hour and equipment-quantity requirements. - **Key Inputs**: Demand mix, process time, yield assumptions, uptime, setup losses, and qualification overhead. - **Planning Horizon**: Supports near-term dispatch planning and long-range capital expenditure decisions. - **Output Metrics**: Required tool count, loading profile, and risk-adjusted spare capacity. **Why Tool capacity planning Matters** - **Throughput Assurance**: Underestimation causes chronic bottlenecks and missed delivery commitments. - **Capital Efficiency**: Overestimation ties up capital in underutilized assets. - **Resilience Planning**: Headroom is needed for PM windows, engineering time, and failure events. - **Ramp Execution**: Accurate planning supports smoother node transitions and demand surges. - **Cost-to-Serve Control**: Capacity right-sizing improves margin and operational predictability. **How It Is Used in Practice** - **Model Construction**: Build tool-level capacity equations with realistic cycle losses and downtime factors. - **Scenario Analysis**: Stress-test plans for demand spikes, yield shifts, and maintenance variability. - **Review Cadence**: Reforecast monthly and adjust purchase or transfer decisions proactively. Tool capacity planning is **a strategic operations function for fab performance** - accurate planning prevents both capacity shortfalls and expensive overbuild.