Detection of process equipment induced defects and distortions using scanner inline metrology

摘要

Furnace anneal is a process step that is required to activate dopants after ion implantation. During furnace anneal, many wafers are typically heated-up during processing and the wafers stay at elevated temperature for a fixed time on the order of hours. Local distortions are sometimes observed close to the wafer edge, especially at higher temperatures or when the boat is close to its end-of-lifc. These local distortions appeal at the locations where the wafer is supported inside the boat (a container in which the wafers are placed) and they are referred to as "boat marks". Figure 1 shows an example of localized distortions due to furnace anneal processing at locations that coincide with two support locations, In many cases, the localized distortions are accompanied by the occurrence of slip lines.