A 23factorial design was used to develop a nitride etchprocess on a single-wafer plasma etching tool. The designfactors are the gap between the electrodes, the gas flo(C2F6is used as the reactant gas), and the RF powerapplied to the cathode (see Figure 3.1 for a schematic ofthe plasma etch tool). Each factor is run at two levels, andthe design is replicated twice. The response variable is theetch rate for silicon nitride (m). The etch rate data areshown in Table 6.4, and the design is shown geometricallyin Figure 6.6.