buffer

Buffers are temporary wafer storage locations inside processing tools to optimize wafer flow and tool utilization. **Purpose**: Decouple wafer feeding from processing, enable parallel operations, store wafers during recipe changes or tool recovery. **Location**: Within EFEM, transfer chamber, or dedicated buffer modules. **Capacity**: Few wafers (2-10 typical) - not long-term storage. **Use cases**: Hold next wafer ready while current processes, store wafers during chamber conditioning, queue wafers for multi-chamber tools. **Cooling stations**: Some buffers include cooling for post-process wafer cooldown before returning to FOUP. **Environment**: Match environment (vacuum, N2, clean air) to adjacent areas. **Management**: Tool controller optimizes buffer usage for throughput. **Pre-heating**: Some tools use buffer stations for wafer pre-heating before process. **Mechanical design**: Slots or pedestals for wafer storage. Minimal contact design. **Throughput impact**: Buffers reduce idle time - robot can fetch next wafer while process runs.