The invention relates to an apparatus, a device and a method for determining local alignment errors which have occurred due to strain and/or distortion of a first substrate relative to a second substrate when the first substrate is joined to the second substrate and for alignment of two wafers by means of position maps, strain maps and/or stress maps of wafers which are recorded during and/or after alignment of the wafers, especially through at least one transparent region of at least one of the wafers, optionally the relative position of the two wafers to one another being corrected especially in-situ.