METHOD OF OBTAINING MEASUREMENTS, APPARATUS FOR PERFORMING A PROCESS STEP AND METROLOGY APPARATUS

Measurements are obtained from locations across a substrate (W') before or after performing a lithographic process step. Examples of such measurements include alignment measurements made prior to applying a pattern to the substrate, and measurements of performance parameters such as overlay, after a pattern has been applied. A set of measurement locations (606, 606' or 606") is selected from among all possible measurement locations (302). At least a subset of the selected measurement locations are selected dynamically (202c), in response to measurements obtained using a preliminary selection (610) of measurement locations. Preliminary measurements of height can be used to select measurement locations for alignment. In another aspect of the disclosure, outlier measurements are detected based on supplementary data such as height measurements or historic data. 在执行光刻过程步骤之前或之后，从衬底(W')上的位置获得测量。这种测量的示例包括在将图案应用到衬底之前进行的对准测量，以及在已经应用图案之后诸如套刻之类的性能参数的测量。从所有可能的测量位置(302)之中选择测量位置集合(606、606'或606")。响应于使用初步选择的测量位置(610)所获得的测量，动态