seasoning wafers

**Seasoning Wafers** are **non-product wafers run through process equipment to condition the chamber or tool after maintenance, idle time, or recipe changes** — restoring the tool's process environment to stable operating conditions before processing product wafers. **Seasoning Purpose** - **Chamber Conditioning**: After maintenance (e.g., chamber clean, parts replacement), the chamber walls need to equilibrate — seasoning deposits a stable film on chamber walls. - **Thermal Equilibrium**: Cold starts require thermal stabilization — run seasoning wafers until temperature profiles stabilize. - **Recipe Transition**: Switching between different process recipes — seasoning clears residual chemicals from the previous recipe. - **Idle Recovery**: Tools sitting idle accumulate moisture and contaminants — seasoning purges these before production. **Why It Matters** - **First-Wafer Effect**: The first wafer after maintenance often processes differently — seasoning prevents this from affecting product. - **Stability**: Seasoning establishes a stable process state — reducing wafer-to-wafer variation. - **Cost**: Seasoning wafers are consumed but produce no product — minimizing seasoning count improves productivity. **Seasoning Wafers** are **warming up the equipment** — conditioning process tools to stable operating conditions before entrusting them with valuable product wafers.