batch wet bench

Batch wet benches process multiple wafers together in chemical baths, the traditional approach to wet processing. **Capacity**: Typically 25-50 wafers per batch (one or two carrier loads). High throughput. **Process flow**: Wafers in carrier move through sequence of chemical tanks and rinse tanks. **Tank sequence**: Often: chemical treatment, overflow rinse, chemical 2, rinse, dry. Automated transfer between tanks. **Advantages**: High throughput, lower cost per wafer, established technology, good for stable processes. **Disadvantages**: All wafers get identical treatment, chemical aging affects uniformity, particle transfer between wafers, batch-to-batch variation. **Chemical management**: Monitor and replenish bath chemistry. Replace baths on schedule or based on analysis. **Cross-contamination**: Particles or contamination can transfer between wafers in same batch. **Applications**: Standard cleans, oxide etches, metal cleans, processes where tight uniformity is not critical. **Trends**: Single-wafer processing replacing batch for many critical processes at advanced nodes. **Equipment manufacturers**: TEL, Screen/DNS, KEDI, JST.