Substrate selection method for calibration and qualification purposes

摘要

This research disclosure relates to a method for selecting one or more substrates. Especially, it is related to a selection method, wherein substrates are selected for calibration and qualification of an apparatus, for example, a lithographic apparatus. Typically, flat substrates, for example, flat wafers, are used to verify a performance parameter of an apparatus used during a lithography process. For example, the apparatus may be a photolithographic exposure apparatus, an imprint lithographic apparatus, or a metrology apparatus that is used to monitor and qualify processed wafers. However, a flat wafer is only a baseline for any customer to build-up a device. For a manufacturing a device, multiple processing steps have to be followed. These can alter the wafer contribution towards overlay and or focus performance.