Lithographic apparatus and device manufacturing method

A lithographic apparatus and method comprise an illumination system arranged to provide a radiation beam, a support structure configured to support a product patterning device and a metrology target patterning device. The product patterning device imparts a radiation beam derived from the illumination system with a product pattern in its cross-section representing features of a product device to be formed. The metrology target patterning device imparts the radiation beam with a metrology target pattern in its cross-section representing at least one metrology target. The product patterning device is separate from the metrology target patterning device. A substrate table holds a substrate. A projection system project the radiation patterned by the product patterning device and the metrology target patterning device onto a target portion of the substrate. A metrology target patterning device controller adjusts the metrology target pattern independently of the product pattern.