Metrology system and lithography system

A metrology system is disclosed, the metrology system comprising: a pre-alignment metrology tool operable to measure a plurality of targets on a substrate to obtain measurement data; and a processing unit. The processing unit is operable to: process the measurement data to determine, for each target, at least one location distribution describing a change in the location value over at least a portion of the target; and determining a measurement correction from the at least one position distribution, the measurement correction correcting an intra-target variation in each of the targets, the measurement correction being used to correct a measurement performed by the alignment sensor. 公开了一种量测系统，该量测系统包括：可操作以测量衬底上的多个目标以获取测量数据的预对准量测工具；以及处理单元。处理单元可操作以：处理所述测量数据以针对每个目标确定至少一个位置分布，该位置分布描述所述位置值在所述目标的至少部分之上的变化；以及根据所述至少一个位置分布确定测量校正，该测量校正校正所述目标中的每个目标中的目标内变化，所述测量校正用于校正由对准传感器执行的测量。