The internal configuration of a single wafer process chamber within the cluster tool depends on the intended process to be performed within the chamber. Figure 3 shows a schematic of a representative single wafer CVD chamber. Precursor is fed to the chamber using a showerhead arrangement that ensures a uniform concentration of precursor over the entire wafer face. The showerhead and chamber walls are cooled to temperatures below which deposition should not occur in order to minimize any potential for particle production by the spalling of deposits on these surfaces. The substrate is heated using resistive or optical heating of the wafer chuck. The gas exits the chamber via exhaust ports below the wafer. The geometries within the chamber are precisely designed to optimize process performance for zero particle generation, even film uniformity and desirable film properties.
Figure 4 shows a schematic for a cluster tool configuration. Wafers are introduced into a transfer station using a load-lock arrangement and FOUP protocols. Once the transfer station has been pumped to vacuum conditions, a robotic wafer handler (in the central chamber) picks up the wafer and transfers it to a process chamber. The process chamber is sealed and the wafer undergoes the intended process, in this discussion thin film deposition by CVD. When the process is complete, the wafer is extracted from the process module and transferred either to another process module (i.e., gate stack processing, annealing, etc) or to a cooling module then to the transfer station that is brought back to atmospheric pressure so that the processed wafer can be removed from the system.
Thin Film Deposition