Single-wafer processing tools handle one wafer at a time (per chamber), providing superior process control and uniformity compared to batch tools. Most advanced semiconductor equipment uses single-wafer architecture.

Why Single-Wafer?

Uniformity: Each wafer receives identical process conditions with no wafer-to-wafer variation within a batch. Control: Real-time feedback and endpoint detection per wafer (e.g., optical emission in etch, reflectometry in CMP). Flexibility: Quick recipe changes between wafers with no need to fill a full batch before processing. Contamination: Cross-contamination between wafers is minimized.

Single-Wafer vs. Batch

Single-wafer: 1 wafer per chamber, 15-60 WPH per chamber. Used for etch, CVD, PVD, CMP, litho track, implant. Batch: 25-150 wafers simultaneously, longer process times. Used for diffusion furnaces, wet benches, LPCVD. Industry trend: Shifted from batch to single-wafer for most steps at advanced nodes.

Multi-Chamber Platforms

Modern single-wafer tools use cluster platforms (e.g., Applied Endura, Centura; LAM Flex) with 2-6 process chambers around a central vacuum transfer robot. Throughput equals chambers multiplied by per-chamber WPH. Different chambers can run different processes (e.g., pre-clean + barrier + seed in a PVD cluster). Vacuum transfer between chambers eliminates air exposure between sequential steps.