METHOD AND APPARATUS TO DETERMINE PATTERNING PROCESS PARAMETER

A metrology target includes: a first structure arranged to be created by a first patterning process; and a second structure arranged to be created by a second patterning process, wherein the first structure and/or second structure is not used to create a functional aspect of a device pattern; the first and second structures together form one or more instances of a unit cell; and the unit cell having geometric symmetry at a nominal physical configuration; the unit cell has a feature that causes, at a different physical configuration than the nominal physical configuration due to a relative shift in pattern placement in the first patterning process, the second patterning process and/or another patterning process, an asymmetry in the unit cell. 种量测目标包括：第结构，被布置为由第图案化工艺创建；和第二结构，被布置为由第二图案化工艺创建，其中所述第结构和/或所述第二结构不被用来创建器件图案的功能方面，其中所述第结构和所述第二结构起形成单位单元的个或多个实例，所述单位单元在标称物理配置下具有几何对称性，并且其中所述单位单元具有特征，所述特征由于所述第图案化工艺、所述第二图案化工艺和/或另图案化工艺中的图案放置的相对偏移而在与所述标称物理配置不同的物理配置下引起所述单位单元中的不对称性。